Radiation diagnostics has made significant progress in the last three decades, primarily due to the introduction of computed tomography (CT), ultrasound (US), and magnetic resonance imaging (MRI). However, the initial examination of the patient is still based on traditional imaging methods: radiography, fluorography, fluoroscopy.

Traditional radiation research methods are based on the use of X-rays discovered by Wilhelm Conrad Roentgen in 1895. He did not consider it possible to derive material benefit from the results of scientific research, since “... his discoveries and inventions

belong to humanity, and. they shall not be hindered in any way by patents, licenses, contracts, or the control of any group of people.” Traditional X-ray research methods are called projection visualization methods, which, in turn, can be divided into three main groups:

Direct analogue methods;

Indirect analogue methods;

Digital methods.

In direct analogue methods, an image is formed directly in a radiation-receiving medium (X-ray film, fluorescent screen), whose response to radiation is not discrete, but constant. The main analogue research methods are direct radiography and direct fluoroscopy.

Direct radiography- basic method of radiation diagnostics. It consists in the fact that X-rays passing through the patient's body create an image directly on the film. X-ray film is coated with a photographic emulsion containing silver bromide crystals, which are ionized by photon energy (the higher the radiation dose, the more silver ions are formed). This is the so-called latent image. During the developing process, metallic silver forms dark areas on the film, and during the fixing process, the silver bromide crystals are washed out and transparent areas appear on the film.

Direct radiography produces static images with the best possible spatial resolution. This method is used to obtain chest x-rays.

Currently, direct radiography is rarely used to obtain a series of full-format images in cardiac angiographic studies.

Direct fluoroscopy (transillumination) lies in the fact that the radiation passing through the patient’s body, hitting the fluorescent screen, creates a dynamic projection image. Currently, this method is practically not used due to the low brightness of the image and the high radiation dose to the patient.

Indirect fluoroscopy almost completely replaced transillumination. The fluorescent screen is part of the electrical

throne-optical converter, which enhances the image brightness by more than 5000 times. The radiologist was able to work in daylight. The resulting image is reproduced by the monitor and can be recorded on film, video recorder, magnetic or optical disk.

Indirect fluoroscopy is used to study dynamic processes, such as contractile activity of the heart, blood flow through the vessels

Fluoroscopy is also used to identify intracardial calcifications, detect paradoxical pulsation of the left ventricle of the heart, pulsation of vessels located in the roots of the lungs, etc.

In digital methods of radiation diagnostics, primary information (in particular, the intensity of X-ray radiation, echo signal, magnetic properties of tissues) is presented in the form of a matrix (rows and columns of numbers). The digital matrix is ​​transformed into a matrix of pixels (visible image elements), where each number value is assigned a particular shade of the gray scale.

A common advantage of all digital methods of radiation diagnostics compared to analog ones is the ability to process and store data using a computer.

A variant of digital projection radiography is digital (digital) subtraction angiography. First, a native digital radiograph is taken, then a digital radiograph is taken after intravascular administration of a contrast agent, and then the first is subtracted from the second image. As a result, only the vascular bed is imaged.

CT scan- a method of obtaining tomographic images (“slices”) in the axial plane without overlapping images of adjacent structures. Rotating around the patient, the X-ray tube emits finely collimated fan-shaped beams of rays perpendicular to the long axis of the body (axial projection). In the tissues under study, part of the X-ray photons is absorbed or scattered, while the other propagates to special highly sensitive detectors, generating in the latter electrical signals proportional to

intensity of transmitted radiation. When detecting differences in radiation intensity, CT detectors are two orders of magnitude more sensitive than X-ray film. A computer (special processor) working using a special program evaluates the attenuation of the primary beam in various directions and calculates the “X-ray density” indicators for each pixel in the plane of the tomographic slice.

While inferior to full-length radiography in spatial resolution, CT is significantly superior to it in contrast resolution.

Spiral (or helical) CT combines constant rotation of the X-ray tube with translational movement of the table with the patient. As a result of the study, the computer receives (and processes) information about a large array of the patient’s body, and not about one section.

Spiral CT makes it possible to reconstruct two-dimensional images in various planes and allows the creation of three-dimensional virtual images of human organs and tissues.

CT is an effective method for detecting heart tumors, detecting complications of myocardial infarction, and diagnosing pericardial diseases. With the advent of multislice (multi-row) spiral computed tomographs, it is possible to study the condition of coronary arteries and shunts.

Radionuclide diagnostics (radionuclide imaging)

is based on the detection of radiation that is emitted by a radioactive substance located inside the patient's body. Introduced to the patient intravenously (less often by inhalation), radiopharmaceuticals are a carrier molecule (determining the path and nature of distribution of the drug in the patient’s body), which includes a radionuclide - an unstable atom that spontaneously decays with the release of energy. Since radionuclides that emit gamma photons (high-energy electromagnetic radiation) are used for imaging purposes, a gamma camera (scintillation camera) is used as a detector. For radionuclide

Heart studies use various drugs labeled with technetium-99t and thallium-201. The method allows you to obtain data on the functional characteristics of the heart chambers, myocardial perfusion, the existence and volume of intracardiac blood discharge.

Single-photon emission computed tomography (SPECT) is a variant of radionuclide imaging in which a gamma camera rotates around the patient's body. Determining the level of radioactivity from different directions allows you to reconstruct tomographic sections (similar to X-ray CT). This method is currently widely used in cardiac research.

Positron emission tomography (PET) uses the annihilation effect of positrons and electrons. Positron-emitting isotopes (15O, 18F) are produced using a cyclotron. In the patient's body, a free positron reacts with the nearest electron, which leads to the formation of two γ-photons, scattering in strictly diametric directions. Special detectors are available to detect these photons. The method makes it possible to determine the concentration of radionuclides and waste products labeled with them, as a result of which it is possible to study metabolic processes in various stages of diseases.

The advantage of radionuclide imaging is the ability to study physiological functions; the disadvantage is low spatial resolution.

Cardiological ultrasound research techniques Not

carry the potential for radiation damage to organs and tissues of the human body and in our country traditionally relate to functional diagnostics, which dictates the need to describe them in a separate chapter.

Magnetic resonance imaging (MRI)- a diagnostic imaging method in which the information carrier is radio waves. When exposed to a strong uniform magnetic field, protons (hydrogen nuclei) of the patient’s body tissues line up along the lines of this field and begin to rotate around a long axis with a strictly defined frequency. Exposure to lateral electromagnetic radio frequency pulses corresponding to this frequency (resonant frequency) leads to energy accumulation

and deflection of protons. After the pulses stop, the protons return to their original position, releasing the accumulated energy in the form of radio waves. The characteristics of these radio waves depend on the concentration and relative positions of protons and on the relationships of other atoms in the substance under study. The computer analyzes the information that comes from radio antennas located around the patient and builds a diagnostic image on a principle similar to the creation of images in other tomographic methods.

MRI - most violent evolving method assessment of the morphological and functional characteristics of the heart and blood vessels, has a wide variety of applied techniques.

Angiocardiographic method used to study the chambers of the heart and blood vessels (including coronary ones). A catheter is inserted into the vessel (most often the femoral artery) using the puncture method (using the Seldinger method) under fluoroscopy control. Depending on the volume and nature of the study, the catheter is advanced into the aorta, heart chambers, and contrast is performed - the introduction of a certain amount of contrast agent to visualize the structures being studied. The study is filmed with a movie camera or recorded with a video recorder in several projections. The speed of passage and the nature of filling of the vessels and chambers of the heart with a contrast agent make it possible to determine the volumes and parameters of the function of the ventricles and atria of the heart, the consistency of the valves, aneurysms, stenoses and vascular occlusions. At the same time, you can measure blood pressure and oxygen saturation (cardiac probing).

Based on the angiographic method, it is currently actively developing interventional radiology- the totality is small invasive methods and methods of therapy and surgery for a number of human diseases. Thus, balloon angioplasty, mechanical and aspiration recanalization, thrombectomy, thrombolysis (fibrinolysis) make it possible to restore the normal diameter of blood vessels and blood flow through them. Stenting (prosthetics) of vessels improves the results of percutaneous transluminal balloon angioplasty for restenosis and intimal detachments of vessels, and allows strengthening their walls in case of aneurysms. Using balloon catheters

large diameter, valvuloplasty is performed - expansion of stenotic heart valves. Angiographic embolization of vessels allows you to stop internal bleeding and “turn off” the function of an organ (for example, the spleen with hypersplenism). Embolization of a tumor is performed in case of bleeding from its vessels and to reduce blood supply (before surgery).

Interventional radiology, being a complex of minimally invasive methods and techniques, allows for gentle treatment of diseases that previously required surgical intervention.

Today, the level of development of interventional radiology demonstrates the quality of technological and professional development of radiology specialists.

Thus, radiation diagnostics is a complex of various methods and techniques of medical imaging, in which information is received and processed from transmitted, emitted and reflected electromagnetic radiation. In cardiology, radiation diagnostics has undergone significant changes in recent years and has taken a vital place in both the diagnosis and treatment of heart and vascular diseases.

Radiation diagnostics and radiation therapy are components of medical radiology (as this discipline is commonly called abroad).

Radiation diagnostics is a practical discipline that studies the use of various radiations in order to recognize numerous diseases, to study the morphology and function of normal and pathological human organs and systems. Radiation diagnostics includes: radiology, including computed tomography (CT); radionuclide diagnostics, ultrasound diagnostics, magnetic resonance imaging (MRI), medical thermography and interventional radiology associated with the performance of diagnostic and therapeutic procedures under the control of radiation research methods.

The role of radiation diagnostics in general and in dentistry in particular cannot be overestimated. Radiation diagnostics is characterized by a number of features. Firstly, it has widespread use both in somatic diseases and in dentistry. In the Russian Federation, more than 115 million x-ray examinations, more than 70 million ultrasound examinations and more than 3 million radionuclide examinations are performed annually. Secondly, radiation diagnostics is informative. With its help, 70-80% of clinical diagnoses are established or supplemented. Radiation diagnostics is used for 2000 different diseases. Dental examinations account for 21% of all x-ray examinations in the Russian Federation and almost 31% in the Omsk region. Another feature is that the equipment used in radiation diagnostics is expensive, especially computer and magnetic resonance imaging scanners. Their cost exceeds 1 - 2 million dollars. Abroad, due to the high price of equipment, radiation diagnostics (radiology) is the most financially intensive branch of medicine. Another feature of radiation diagnostics is that radiology and radionuclide diagnostics, not to mention radiation therapy, pose a radiation hazard to the personnel of these services and patients. This circumstance obliges doctors of all specialties, including dentists, to take this fact into account when prescribing X-ray examinations.

Radiation therapy is a practical discipline that studies the use of ionizing radiation for therapeutic purposes. Currently, radiation therapy has a large arsenal of sources of quantum and corpuscular radiation used in oncology and in the treatment of non-tumor diseases.

Currently, no medical disciplines can do without radiation diagnostics and radiation therapy. There is practically no clinical specialty in which radiation diagnostics and radiation therapy are not associated with the diagnosis and treatment of various diseases.

Dentistry is one of those clinical disciplines where x-ray examination occupies the main place in the diagnosis of diseases of the dental system.

Radiation diagnostics uses 5 types of radiation, which, based on their ability to cause ionization of the environment, are classified as ionizing or non-ionizing radiation. Ionizing radiation includes X-rays and radionuclide radiation. Non-ionizing radiation includes ultrasonic, magnetic, radio frequency, and infrared radiation. However, when using these radiations, single acts of ionization may occur in atoms and molecules, which, however, do not cause any damage to human organs and tissues and are not dominant in the process of interaction of radiation with matter.

Basic physical characteristics of radiation

X-ray radiation is an electromagnetic vibration artificially created in special tubes of X-ray machines. This radiation was discovered by Wilhelm Conrad Roentgen in November 1895. X-rays belong to the invisible spectrum of electromagnetic waves with wavelengths ranging from 15 to 0.03 angstroms. The energy of the quanta, depending on the power of the equipment, ranges from 10 to 300 or more KeV. The speed of propagation of X-ray quanta is 300,000 km/sec.

X-rays have certain properties that determine their use in medicine for the diagnosis and treatment of various diseases. The first property is penetrating ability, the ability to penetrate solid and opaque bodies. The second property is their absorption in tissues and organs, which depends on the specific gravity and volume of the tissues. The denser and more voluminous the fabric, the greater the absorption of rays. Thus, the specific gravity of air is 0.001, fat 0.9, soft tissue 1.0, bone tissue 1.9. Naturally, bones will have the greatest X-ray absorption. The third property of X-rays is their ability to cause the glow of fluorescent substances, which is used when conducting transillumination behind the screen of an X-ray diagnostic apparatus. The fourth property is photochemical, due to which an image is obtained on X-ray photographic film. The last, fifth property is the biological effect of X-rays on the human body, which will be the subject of a separate lecture.

X-ray research methods are performed using an X-ray machine, the device of which includes 5 main parts:

• - X-ray emitter (X-ray tube with cooling system);
• - power supply device (transformer with electric current rectifier);
• - radiation receiver (fluorescent screen, film cassettes, semiconductor sensors);
• - tripod device and table for positioning the patient;
• - Remote Control.

The main part of any X-ray diagnostic apparatus is the X-ray tube, which consists of two electrodes: the cathode and the anode. A direct electric current is supplied to the cathode, which glows the cathode filament. When a high voltage is applied to the anode, electrons, as a result of a potential difference, fly from the cathode with high kinetic energy and are decelerated at the anode. When electrons are decelerated, X-rays are formed - bremsstrahlung rays emerging from the X-ray tube at a certain angle. Modern X-ray tubes have a rotating anode, the speed of which reaches 3000 revolutions per minute, which significantly reduces the heating of the anode and increases the power and service life of the tube.

The X-ray method in dentistry began to be used shortly after the discovery of X-rays. Moreover, it is believed that the first X-ray photograph in Russia (in Riga) captured the jaws of a sawfish in 1896. In January 1901, an article appeared on the role of radiography in dental practice. In fact, dental radiology is one of the earliest branches of medical radiology. It began to develop in Russia when the first X-ray rooms appeared. The first specialized X-ray room at the Dental Institute in Leningrad was opened in 1921. In Omsk, general purpose X-ray rooms (where dental photographs were also taken) opened in 1924.

The X-ray method includes the following techniques: fluoroscopy, that is, obtaining an image on a fluorescent screen; radiography - obtaining an image on x-ray film placed in a radiolucent cassette, where it is protected from ordinary light. These methods are the main ones. Additional ones include: tomography, fluorography, X-ray densitometry, etc.

Tomography - obtaining layer-by-layer images on X-ray film. Fluorography is the production of a smaller X-ray image (72×72 mm or 110×110 mm) as a result of photographic transfer of the image from a fluorescent screen.

The X-ray method also includes special, radiopaque studies. When conducting these studies, special techniques and devices are used to obtain x-ray images, and they are called radiopaque because the study uses various contrast agents that block x-rays. Contrast techniques include: angio-, lympho-, uro-, cholecystography.

The X-ray method also includes computed tomography (CT, RCT), which was developed by the English engineer G. Hounsfield in 1972. For this discovery, he and another scientist, A. Cormack, received the Nobel Prize in 1979. Computed tomographs are currently available in Omsk: in the Diagnostic Center, Regional clinical hospital, Irtyshka Central Basin Clinical Hospital. The principle of X-ray CT is based on the layer-by-layer examination of organs and tissues with a thin pulsed beam of X-ray radiation in cross section, followed by computer processing of subtle differences in the absorption of X-rays and the secondary acquisition of a tomographic image of the object under study on a monitor or film. Modern X-ray computed tomographs consist of 4 main parts: 1- scanning system (X-ray tube and detectors); 2 - high-voltage generator - power source of 140 kV and current up to 200 mA; 3 - control panel (control keyboard, monitor); 4 - a computer system designed for preliminary processing of information received from detectors and obtaining an image with an estimate of the density of the object. CT has a number of advantages over conventional x-ray examination, primarily its greater sensitivity. It allows you to differentiate individual tissues from each other, differing in density within 1 - 2% and even 0.5%. With radiography, this figure is 10 - 20%. CT provides precise quantitative information about the size of the density of normal and pathological tissues. When using contrast agents, using the so-called intravenous contrast enhancement increases the possibility of more accurate detection pathological formations, carry out differential diagnosis.

In recent years, a new X-ray system for obtaining digital (digital) images has appeared. Each digital image consists of many individual points, which correspond to the numerical intensity of the glow. The brightness level of the dots is captured in special device- an analog-to-digital converter (ADC), in which the electrical signal carrying information about the X-ray image is converted into a series of numbers, that is, digital coding of the signals occurs. To turn digital information into an image on a television screen or film, you need a digital-to-analog converter (DAC), where the digital image is transformed into an analog, visible image. Digital radiography will gradually replace conventional film radiography, since it is characterized by rapid image acquisition, does not require photochemical processing of the film, has greater resolution, allows mathematical image processing, archiving on magnetic storage media, and provides a significantly lower radiation dose to the patient (approximately 10 times), increases the throughput of the office.

The second method of radiation diagnostics is radionuclide diagnostics. Various radioactive isotopes and radionuclides are used as radiation sources.

Natural radioactivity was discovered in 1896 by A. Becquerel, and artificial radioactivity in 1934 by Irène and Joliot Curie. Most often in radionuclide diagnostics, radionuclides (RN) gamma emitters and radiopharmaceuticals (RP) with gamma emitters are used. A radionuclide is an isotope whose physical properties determine its suitability for radiodiagnostic studies. Radiopharmaceuticals are diagnostic and therapeutic agents based on radioactive nuclides - substances of inorganic or organic nature, the structure of which contains a radioactive element.

In dental practice and in radionuclide diagnostics in general, the following radionuclides are widely used: Tc 99 m, In-113 m, I-125, Xe-133, less often I-131, Hg-197. Based on their behavior in the body, radiopharmaceuticals used for radionuclide diagnostics are conventionally divided into 3 groups: organotropic, tropic to the pathological focus, and without pronounced selectivity or tropism. The tropism of radiopharmaceuticals can be directed, when the drug is included in the specific metabolism of the cells of a certain organ in which it accumulates, and indirect, when a temporary concentration of radiopharmaceuticals occurs in the organ along the way of its passage or excretion from the body. In addition, secondary selectivity is also distinguished, when a drug, not having the ability to accumulate, causes chemical transformations in the body that cause the emergence of new compounds that are already accumulated in certain organs or tissues. The most common launch vehicle currently is Tc 99 m, which is a daughter nuclide of radioactive molybdenum Mo 99. Tc 99 m is formed in a generator where Mo-99 decays by beta decay to form long-lived Tc-99 m. The latter, upon decay, emits gamma quanta with an energy of 140 keV (the most technically convenient energy). The half-life of Tc 99 m is 6 hours, which is sufficient for all radionuclide studies. It is excreted from the blood in the urine (30% within 2 hours) and accumulates in the bones. The preparation of radiopharmaceuticals based on the Tc 99 m label is carried out directly in the laboratory using a set of special reagents. The reagents, in accordance with the instructions supplied with the kits, are mixed in a certain way with the technetium eluate (solution) and a radiopharmaceutical is formed within a few minutes. Radiopharmaceutical solutions are sterile and pyrogen-free and can be administered intravenously. Numerous methods of radionuclide diagnostics are divided into 2 groups depending on whether the radiopharmaceutical is introduced into the patient’s body or is used to study isolated samples of biological media (blood plasma, urine and pieces of tissue). In the first case, the methods are combined into a group of in vivo studies, in the second case - in vitro. Both methods have fundamental differences in indications, execution techniques and results obtained. In clinical practice, complex studies are most often used. In vitro radionuclide studies are used to determine the concentration of various biologically active compounds in human blood serum, the number of which currently reaches more than 400 (hormones, drugs, enzymes, vitamins). They are used to diagnose and evaluate pathologies of the reproductive, endocrine, hematopoietic and immunological systems of the body. Most modern reagent kits are based on radioimmunoassay (RIA), which was first proposed by R. Yalow in 1959, for which the author was awarded the Nobel Prize in 1977.

Recently, along with RIA, a new technique of radioreceptor analysis (RRA) has been developed. PRA is also based on the principle of competitive equilibrium of a labeled ligand (labeled antigen) and the test substance in the serum, but not with antibodies, but with receptor bonds of the cell membrane. RRA differs from RIA in the shorter period of time for establishing the technique and even greater specificity.

The basic principles of in vivo radionuclide studies are:

1. Study of the distribution features of the administered radiopharmaceuticals in organs and tissues;

2. Determination of the dynamics of radiopharmaceutical absorption in the patient. Methods based on the first principle characterize the anatomical and topographical state of an organ or system and are called static radionuclide studies. Methods based on the second principle make it possible to assess the state of the functions of the organ or system being studied and are called dynamic radionuclide studies.

There are several methods for measuring the radioactivity of the body or its parts after administration of radiopharmaceuticals.

Radiometry. This is a technique for measuring the intensity of the flow of ionizing radiation per unit of time, expressed in conventional units - pulses per second or minute (imp/sec). For measurements, radiometric equipment (radiometers, complexes) is used. This technique is used to study the accumulation of P 32 in skin tissues, to study the thyroid gland, to study the metabolism of proteins, iron, and vitamins in the body.

Radiography is a method of continuous or discrete recording of the processes of accumulation, redistribution and removal of radiopharmaceuticals from the body or individual organs. For these purposes, radiographs are used, in which a counting rate meter is connected to a recorder that draws a curve. The radiograph may contain one or more detectors, each of which carries out measurements independently of each other. If clinical radiometry is intended for single or several repeated measurements of the radioactivity of the body or its parts, then using radiography it is possible to trace the dynamics of accumulation and its elimination. A typical example of radiography is the study of the accumulation and removal of radiopharmaceuticals from the lungs (xenon), from the kidneys, from the liver. The radiographic function in modern devices is combined in a gamma camera with visualization of organs.

Radionuclide imaging. Methodology for creating a picture of the spatial distribution in organs of radiopharmaceuticals introduced into the body. Radionuclide imaging currently includes the following types:

• a) scanning,
• b) scintigraphy using a gamma camera,
• c) single-photon and two-photon positron emission tomography.

Scanning is a method of visualizing organs and tissues using a scintillation detector moving over the body. The device that conducts the study is called a scanner. The main disadvantage is the long duration of the study.

Scintigraphy is the acquisition of images of organs and tissues by recording on a gamma camera the radiation emanating from radionuclides distributed in organs and tissues and in the body as a whole. Scintigraphy is currently the main method of radionuclide imaging in the clinic. It makes it possible to study the rapidly occurring processes of distribution of radioactive compounds introduced into the body.

Single photon emission tomography (SPET). SPET uses the same radiopharmaceuticals as scintigraphy. In this device, the detectors are located in a rotational tomocamera, which rotates around the patient, making it possible, after computer processing, to obtain an image of the distribution of radionuclides in different layers of the body in space and time.

Two-photon emission tomography (TPET). For DFET, a positron-emitting radionuclide (C 11, N 13, O 15, F 18) is injected into the human body. Positrons emitted by these nuclides annihilate near the nuclei of atoms with electrons. During annihilation, the positron-electron pair disappears, forming two gamma quanta with an energy of 511 keV. These two quanta, scattering in strictly opposite directions, are recorded by two also oppositely located detectors.

Computer signal processing allows you to obtain a three-dimensional and color image of the research object. The spatial resolution of DFET is worse than that of X-ray computed tomography and magnetic resonance imaging, but the sensitivity of the method is fantastic. DFET makes it possible to detect changes in the consumption of glucose, labeled with C 11, in the “eye center” of the brain, when opening the eyes; it is possible to identify changes in the thought process to determine the so-called. "soul", located, as some scientists believe, in the brain. The disadvantage of this method is that its use is only possible if there is a cyclotron, a radiochemical laboratory for obtaining short-lived nuclides, a positron tomograph and a computer for information processing, which is very expensive and cumbersome.

In the last decade, ultrasound diagnostics based on the use of ultrasound radiation has entered healthcare practice on a wide front.

Ultrasound radiation belongs to the invisible spectrum with a wavelength of 0.77-0.08 mm and an oscillation frequency of over 20 kHz. Sound vibrations with a frequency of more than 10 9 Hz are classified as hypersound. Ultrasound has certain properties:

• 1. In a homogeneous medium, ultrasound (US) is distributed rectilinearly at the same speed.
• 2. At the boundary of different media with unequal acoustic density, some of the rays are reflected, another part is refracted, continuing their linear propagation, and the third is attenuated.

Ultrasonic attenuation is determined by the so-called IMPEDANCE - ultrasonic attenuation. Its value depends on the density of the medium and the speed of propagation of the ultrasonic wave in it. The higher the gradient of the difference in the acoustic density of the boundary media, the larger part of the ultrasonic vibrations is reflected. For example, at the boundary of the transition of ultrasound from air to skin, almost 100% of vibrations (99.99%) are reflected. That is why during ultrasound examination it is necessary to lubricate the surface of the patient’s skin with aqueous jelly, which acts as a transition medium that limits the reflection of radiation. Ultrasound is almost completely reflected from calcifications, giving a sharp weakening of echo signals in the form of an acoustic track (distal shadow). On the contrary, when examining cysts and cavities containing fluid, a track appears due to compensatory amplification of signals.

Three methods of ultrasound diagnostics are most widespread in clinical practice: one-dimensional examination (echography), two-dimensional examination (scanning, sonography) and Dopplerography.

1. One-dimensional echography is based on the reflection of U3 pulses, which are recorded on the monitor in the form of vertical bursts (curves) on a straight horizontal line (scan line). The one-dimensional method provides information about the distances between tissue layers along the path of the ultrasound pulse. One-dimensional echography is still used in the diagnosis of diseases of the brain (echoencephalography), the organ of vision, and the heart. In neurosurgery, echoencephalography is used to determine the size of the ventricles and the position of the median diencephalic structures. In ophthalmological practice, this method is used to study the structures of the eyeball, opacities vitreous, retinal or choroidal detachment, to clarify the localization of a foreign body or tumor in the orbit. In a cardiology clinic, echography evaluates the structure of the heart in the form of a curve on a video monitor called an M-echogram (motion).

2. Two-dimensional ultrasound scanning (sonography). Allows you to obtain a two-dimensional image of organs (B-method, brightness - brightness). During sonography, the transducer moves in a direction perpendicular to the line of propagation of the ultrasound beam. The reflected impulses merge in the form of luminous points on the monitor. Since the sensor is in constant motion and the monitor screen has a long glow, the reflected impulses merge, forming a cross-sectional image of the organ being examined. Modern devices have up to 64 degrees of color gradation, called the “gray scale,” which provides differences in the structures of organs and tissues. The display produces an image in two qualities: positive (white background, black image) and negative (black background, white image).

Real-time visualization shows dynamic images of moving structures. It is provided by multidirectional sensors with up to 150 or more elements - linear scanning, or from one, but making rapid oscillatory movements - sectoral scanning. A picture of the organ being examined during ultrasound in real time appears on the video monitor instantly from the moment of the examination. To examine organs adjacent to open cavities (rectum, vagina, oral cavity, esophagus, stomach, colon) - use special intrarectal, intravaginal and other intracavitary sensors.

3.Doppler echolocation - ultrasound method diagnostic study moving objects (blood elements), based on the Doppler effect. The Doppler effect is associated with a change in the frequency of the ultrasonic wave perceived by the sensor, which occurs as a result of the movement of the object under study relative to the sensor: the frequency of the echo signal reflected from the moving object differs from the frequency of the emitted signal. There are two modifications of Doppler ultrasound:

• a) - continuous, which is most effective when measuring high blood flow velocities in places of vascular constriction, however, continuous Dopplerography has a significant drawback - it gives the total speed of the object, and not just the blood flow;
• b) - pulse Dopplerography is free of these disadvantages and allows you to measure low velocities at great depths or high velocities at shallow depths in several small control objects.

Dopplerography is used clinically to study the shape of contours and gaps blood vessels(narrowing, thrombosis, individual sclerotic plaques). In recent years, the combination of sonography and Dopplerography (the so-called duplex sonography) has become important in the ultrasound diagnostic clinic, which makes it possible to identify images of blood vessels (anatomical information) and obtain a record of the blood flow curve in them (physiological information), also in modern ultrasound machines have a system that allows you to color multidirectional blood flows in different colors(blue and red), so-called color Doppler mapping. Duplex sonography and color mapping make it possible to monitor the blood supply to the placenta, heart contractions in the fetus, the direction of blood flow in the chambers of the heart, determine the reverse flow of blood in the portal vein system, calculate the degree of vascular stenosis, etc.

In recent years, some biological effects in personnel during ultrasound examinations have become known. The action of ultrasound through the air primarily affects the critical volume, which is the level of sugar in the blood, electrolyte shifts are noted, fatigue increases, and headache, nausea, tinnitus, irritability. However, in most cases, these signs are nonspecific and have a pronounced subjective coloring. This issue requires further study.

Medical thermography is a method of recording the natural thermal radiation of the human body in the form of invisible infrared radiation. Infrared radiation (IR) is produced by all bodies with a temperature above minus 237 0 C. The wavelength of IIR is from 0.76 to 1 mm. The radiation energy is less than that of visible light quanta. IR is absorbed and weakly scattered, and has both wave and quantum properties. Features of the method:

• 1. Absolutely harmless.
• 2. High research speed (1 - 4 min.).
• 3. Quite accurate - it picks up fluctuations of 0.1 0 C.
• 4. Has the ability to simultaneously assess the functional state of several organs and systems.

Thermographic research methods:

• 1. Contact thermography is based on the use of thermal indicator films on liquid crystals in a color image. By coloring the image using a calorimetric ruler, the temperature of the surface tissues is judged.
• 2. Remote infrared thermography is the most common method of thermography. It provides an image of the thermal relief of the body surface and measurement of temperature in any part of the human body. A remote thermal imager makes it possible to display a person’s thermal field on the device’s screen in the form of a black-and-white or color image. These images can be recorded on photochemical paper and a thermogram can be obtained. Using the so-called active, stress tests: cold, hyperthermic, hyperglycemic, it is possible to identify initial, even hidden violations of thermoregulation of the surface of the human body.

Currently, thermography is used to detect circulatory disorders, inflammatory, tumor and some occupational diseases, especially in dispensary observation. It is believed that this method, while having sufficient sensitivity, does not have high specificity, which makes it difficult to widely use in diagnosing various diseases.

The latest advances in science and technology make it possible to measure temperature internal organs by their own emission of radio waves in the microwave range. These measurements are made using a microwave radiometer. This method has a more promising future than infrared thermography.

A huge event last decade was the introduction into clinical practice a truly revolutionary diagnostic method of nuclear magnetic resonance imaging, currently called magnetic resonance imaging (the word “nuclear” has been removed so as not to cause radiophobia among the population). The magnetic resonance imaging (MRI) method is based on capturing electromagnetic vibrations from certain atoms. The fact is that atomic nuclei containing an odd number of protons and neutrons have their own nuclear magnetic spin, i.e. angular momentum of rotation of the nucleus around its own axis. These atoms include hydrogen, a component of water, which reaches up to 90% in the human body. A similar effect is produced by other atoms containing an odd number of protons and neutrons (carbon, nitrogen, sodium, potassium and others). Therefore, each atom is like a magnet and under normal conditions the axes of angular momentum are located randomly. In a magnetic field of the diagnostic range with a power of the order of 0.35-1.5 T (the unit of measurement of the magnetic field is named after Tesla, a Serbian, Yugoslav scientist with 1000 inventions), atoms are oriented in the direction of the magnetic field parallel or antiparallel. If a radio frequency field (of the order of 6.6-15 MHz) is applied in this state, nuclear magnetic resonance occurs (resonance, as is known, occurs when the excitation frequency coincides with the natural frequency of the system). This radio frequency signal is picked up by detectors and an image is created through a computer system based on proton density (the more protons in the medium, the more intense the signal). The brightest signal gives adipose tissue(high proton density). On the contrary, bone tissue, due to a small amount of water (protons), gives the smallest signal. Each tissue has its own signal.

Magnetic resonance imaging has a number of advantages over other diagnostic imaging methods:

• 1. No radiation exposure,
• 2. There is no need to use contrast agents in most cases of routine diagnostics, since MRI allows you to see With Vessels, especially large and medium ones without contrasting.
• 3. The ability to obtain images in any plane, including three orthoganal anatomical projections, in contrast to X-ray computed tomography, where the study is carried out in an axial projection, and in contrast to ultrasound, where the image is limited (longitudinal, transverse, sectoral).
• 4. High resolution of identifying soft tissue structures.
• 5. There is no need for special preparation of the patient for the study.

In recent years, new methods of radiation diagnostics have appeared: obtaining a three-dimensional image using spiral computed x-ray tomography, a method has emerged using the principle virtual reality with three-dimensional imaging, monoclonal radionuclide diagnostics and some other methods that are at the experimental stage.

Thus, this lecture provides a general description of the methods and techniques of radiation diagnostics; a more detailed description of them will be given in private sections.

GENERAL PRINCIPLES OF RADIATION DIAGNOSTICS

The problems of disease are more complex and difficult than any other that a trained mind has to solve.

A majestic and endless world spreads out around. And every person is also a world, complex and unique. In different ways we strive to explore this world, to understand the basic principles of its structure and regulation, to understand its structure and functions. Scientific knowledge is based on the following research techniques: morphological method, physiological experiment, clinical research, radiation and instrumental methods. However Scientific knowledge is only the first basis for diagnosis. This knowledge is like sheet music for a musician. However, using the same notes, different musicians achieve different effects when performing the same piece. The second basis of diagnosis is art and personal experience doctor“Science and art are as interconnected as the lungs and the heart, so if one organ is perverted, then the other cannot function correctly” (L. Tolstoy).

All this emphasizes the exclusive responsibility of the doctor: after all, every time at the patient’s bedside he makes an important decision. Constantly increasing knowledge and the desire for creativity are the traits of a real doctor. “We love everything - the heat of cold numbers, and the gift of divine visions...” (A. Blok).

Where does any diagnostics begin, including radiation? With deep and solid knowledge about the structure and functions of the systems and organs of a healthy person in all the uniqueness of his gender, age, constitutional and individual characteristics. “For a fruitful analysis of the work of each organ, it is necessary first of all to know its normal activity” (I.P. Pavlov). In this regard, all chapters of Part III of the textbook begin with a brief summary of the radiation anatomy and physiology of the relevant organs.

Dream I.P. Pavlov's concept of capturing the majestic activity of the brain with a system of equations is still far from being realized. In most pathological processes, diagnostic information is so complex and individual that it is not yet possible to express it with a sum of equations. Nevertheless, repeated consideration of similar typical reactions allowed theorists and clinicians to identify typical syndromes of injuries and diseases and to create some images of diseases. This is an important step on the diagnostic path, therefore, in each chapter, after a description of the normal picture of the organs, the symptoms and syndromes of diseases that are most often detected during radiation diagnostics are considered. Let us only add that this is where the doctor’s personal qualities clearly manifest themselves: his observation and ability to discern the leading lesion syndrome in a motley kaleidoscope of symptoms. We can learn from our distant ancestors. We mean the rock paintings of the Neolithic times, which surprisingly accurately reflect the general scheme (image) of the phenomenon.

In addition, each chapter provides a brief description of the clinical picture of a few of the most common and serious illnesses, with which the student should become acquainted both at the department of radiation diagnostics

ki and radiation therapy, and in the process of supervising patients in therapeutic and surgical clinics in senior years.

The actual diagnosis begins with an examination of the patient, and it is very important to choose the right program for its implementation. The leading link in the process of recognizing diseases, of course, remains a qualified clinical examination, but it is no longer limited to examining the patient, but is an organized, purposeful process that begins with an examination and includes the use of special methods, among which radiation occupies a prominent place.

In these conditions, the work of a doctor or group of doctors should be based on a clear program of action, which provides for the order of application of various research methods, i.e. Every doctor should be armed with a set of standard patient examination schemes. These schemes are designed to ensure high diagnostic reliability, savings in effort and money for specialists and patients, priority use of less invasive interventions and reduction in radiation exposure to patients and medical personnel. In this regard, each chapter provides radiation examination schemes for certain clinical and radiological syndromes. This is only a modest attempt to chart a path towards comprehensive X-ray examination in the most common clinical situations. The further task is to move from these limited schemes to genuine diagnostic algorithms that will contain all the data about the patient.

In practice, alas, the implementation of the examination program is associated with certain difficulties: the technical equipment of medical institutions varies, the knowledge and experience of doctors, and the patient’s condition are different. “Wits say that the optimal trajectory is the trajectory along which the rocket never flies” (N.N. Moiseev). Nevertheless, the doctor must choose the best examination path for a particular patient. The noted stages are included in the general scheme of diagnostic examination of the patient.

Anamnesis data and clinical picture diseases

Establishing indications for radiation examination

Choosing a radiation examination method and preparing the patient

Carrying out radiation examination

Analysis of an organ image obtained using radiation methods

Analysis of organ function carried out using radiation methods

Comparison with the results of instrumental and laboratory studies

Conclusion

In order to effectively conduct radiation diagnostics and competently evaluate the results of radiation studies, it is necessary to adhere to strict methodological principles.

First principle: Any radiological examination must be justified. The main argument in favor of performing a radiation procedure should be the clinical need to obtain additional information, without which a complete individual diagnosis cannot be established.

Second principle: when choosing a research method, it is necessary to take into account the radiation (dose) load on the patient. The guidelines of the World Health Organization stipulate that X-ray examination must have undoubted diagnostic and prognostic effectiveness; otherwise, it is a waste of money and poses a health hazard due to the unnecessary use of radiation. If the information content of the methods is equal, preference should be given to the one that does not expose the patient to radiation or is the least significant.

Third principle: When conducting radiation research, you must adhere to the “necessary and sufficient” rule, avoiding unnecessary procedures. The procedure for performing the necessary research- from the most gentle and unburdensome to the more complex and invasive (from simple to complex). However, we must not forget that sometimes it is necessary to immediately perform complex diagnostic interventions due to their high information content and importance for planning the treatment of the patient.

Fourth principle: When organizing a radiation study, you need to take into account economic forces(“cost effectiveness of methods”). When starting to examine a patient, the doctor is obliged to anticipate the costs of its implementation. The cost of some radiation examinations is so high that unwise use of them can affect the budget medical institution. We put the benefit for the patient first, but at the same time we do not have the right to ignore the economics of medical treatment. Not taking it into account means organizing the work of the radiation department incorrectly.

Science is the best modern way of satisfying the curiosity of individuals at the expense of the state.

PREFACE

Medical radiology (radiation diagnostics) is a little over 100 years old. During this historically short period of time, she wrote many bright pages in the chronicle of the development of science - from the discovery of V.K. Roentgen (1895) to the rapid computer processing of medical radiation images.

At the origins of domestic X-ray radiology were M.K. Nemenov, E.S. London, D.G. Rokhlin, D.S. Lindenbraten - outstanding organizers of science and practical healthcare. Such outstanding personalities as S.A. Reinberg, G.A. Zedgenizde, V.Ya. Dyachenko, Yu.N. Sokolov, L.D. Lindenbraten and others made a great contribution to the development of radiation diagnostics.

The main goal of the discipline is to study theoretical and practical issues of general radiation diagnostics (x-ray, radionuclide,

ultrasound, computed tomography, magnetic resonance imaging, etc.) necessary in the future for students to successfully master clinical disciplines.

Today, radiation diagnostics, taking into account clinical and laboratory data, allows 80-85% to recognize the disease.

This guide to radiation diagnostics is compiled in accordance with the State Educational Standard (2000) and the Curriculum approved by VUNMC (1997).

Today, the most common method of radiological diagnosis is traditional x-ray examination. Therefore, when studying radiology, the main attention is paid to methods for studying human organs and systems (fluoroscopy, radiography, ERG, fluorography, etc.), methods for analyzing radiographs and general x-ray semiotics of the most common diseases.

Currently, digital radiography with high image quality is successfully developing. It is distinguished by its speed, the ability to transmit images over a distance, and the convenience of storing information on magnetic media (disks, tapes). An example is X-ray computed tomography (XCT).

The ultrasound method of examination (ultrasound) deserves attention. Due to its simplicity, harmlessness and effectiveness, the method is becoming one of the most common.

CURRENT STATE AND PROSPECTS FOR THE DEVELOPMENT OF RADIOLOGICAL DIAGNOSTICS

Radiation diagnostics (diagnostic radiology) is an independent branch of medicine that combines various methods of obtaining images for diagnostic purposes based on the use of various types of radiation.

Currently, the activities of radiation diagnostics are regulated by the following regulatory documents:

1. Order of the Ministry of Health of the Russian Federation No. 132 dated August 2, 1991 “On improving the radiology diagnostic service.”

2. Order of the Ministry of Health of the Russian Federation No. 253 dated June 18, 1996 “On further improvement of work to reduce radiation doses during medical procedures”

3. Order No. 360 of September 14, 2001. “On approval of the list of radiation research methods.”

Radiation diagnostics includes:

1. Methods based on the use of X-rays.

1). Fluorography

2). Traditional X-ray examination

4). Angiography

2. Methods based on the use of ultrasound radiation 1).Ultrasound

2). Echocardiography

3). Dopplerography

3. Methods based on nuclear magnetic resonance. 1).MRI

2). MP spectroscopy

4. Methods based on the use of radiopharmaceuticals (radiopharmacological drugs):

1). Radionuclide diagnostics

2). Positron emission tomography - PET

3). Radioimmune studies

5.Methods based on infrared radiation (thermophafia)

6.Interventional radiology

Common to all research methods is the use of various radiations (X-rays, gamma rays, ultrasound, radio waves).

The main components of radiation diagnostics are: 1) radiation source, 2) sensing device.

The diagnostic image is usually a combination of different shades of gray color, proportional to the intensity of the radiation hitting the receiving device.

A picture of the internal structure of the study of an object can be:

1) analog (on film or screen)

2) digital (radiation intensity is expressed in the form of numerical values).

All these methods are combined into a common specialty - radiation diagnostics (medical radiology, diagnostic radiology), and the doctors are radiologists (abroad), but for now we have an unofficial “radiology diagnostician”

In the Russian Federation, the term radiology diagnostics is official only to designate a medical specialty (14.00.19); departments also have a similar name. In practical healthcare, the name is conditional and combines 3 independent specialties: radiology, ultrasound diagnostics and radiology (radionuclide diagnostics and radiation therapy).

Medical thermography is a method of recording natural thermal (infrared) radiation. The main factors determining body temperature are: the intensity of blood circulation and the intensity of metabolic processes. Each region has its own “thermal relief”. Using special equipment (thermal imagers), infrared radiation is captured and converted into a visible image.

Patient preparation: discontinuation of medications that affect blood circulation and the level of metabolic processes, prohibition of smoking 4 hours before the examination. There should be no ointments, creams, etc. on the skin.

Hyperthermia is characteristic of inflammatory processes, malignant tumors, thrombophlebitis; hypothermia is observed in case of vasospasms, circulatory disorders in occupational diseases (vibration disease, cerebrovascular accident, etc.).

The method is simple and harmless. However, the diagnostic capabilities of the method are limited.

One of modern methods Ultrasound (ultrasound dowsing) is widely used. The method has become widespread due to its simplicity, accessibility, and high information content. In this case, the frequency of sound vibrations is used from 1 to 20 megahertz (a person hears sound within frequencies from 20 to 20,000 hertz). A beam of ultrasonic vibrations is directed to the area under study, which is partially or completely reflected from all surfaces and inclusions that differ in sound conductivity. The reflected waves are captured by a sensor, processed by an electronic device and converted into a one-dimensional (echography) or two-dimensional (sonography) image.

Based on the difference in the sound density of the picture, one or another diagnostic decision is made. From the scanograms one can judge the topography, shape, size of the organ being studied, as well as pathological changes in it. Being harmless to the body and staff, the method has found wide application in obstetric and gynecological practice, in the study of the liver and biliary tract, retroperitoneal organs and other organs and systems.

Radionuclide methods for imaging various human organs and tissues are rapidly developing. The essence of the method is that radionuclides or radioactive compounds labeled with them are introduced into the body, which selectively accumulate in the corresponding organs. In this case, radionuclides emit gamma quanta, which are detected by sensors and then recorded by special devices (scanners, gamma camera, etc.), which makes it possible to judge the position, shape, size of the organ, distribution of the drug, the speed of its elimination, etc.

Within the framework of radiation diagnostics, a new promising direction is emerging - radiological biochemistry (radioimmune method). At the same time, hormones, enzymes, tumor markers, drugs, etc. are studied. Today, more than 400 biologically active substances are determined in vitro; Methods of activation analysis are being successfully developed - determining the concentration of stable nuclides in biological samples or in the body as a whole (irradiated with fast neutrons).

The leading role in obtaining images of human organs and systems belongs to X-ray examination.

With the discovery of X-rays (1895), the age-old dream of a doctor came true - to look inside a living organism, study its structure, work, and recognize a disease.

Currently, there are a large number of X-ray examination methods (non-contrast and using artificial contrast), which make it possible to examine almost all human organs and systems.

Recently, digital imaging technologies (low-dose digital radiography), flat panels - detectors for REOP, X-ray image detectors based on amorphous silicon, etc. - have been increasingly introduced into practice.

The advantages of digital technologies in radiology: reduction of the radiation dose by 50-100 times, high resolution (objects 0.3 mm in size are visualized), film technology is eliminated, office throughput increases, an electronic archive is formed with quick access, and the ability to transmit images over a distance.

Interventional radiology is closely related to radiology - a combination of diagnostic and therapeutic measures in one procedure.

Main directions: 1) X-ray vascular interventions (expansion of narrowed arteries, blockage of blood vessels with hemangiomas, vascular prosthetics, stopping bleeding, removal of foreign bodies, supply of drugs to the tumor), 2) extravasal interventions (catheterization of the bronchial tree, puncture of the lung, mediastinum, decompression with obstructive jaundice, administration of drugs that dissolve stones, etc.).

CT scan. Until recently, it seemed that the methodological arsenal of radiology was exhausted. However, computed tomography (CT) was born, revolutionizing X-ray diagnostics. Almost 80 years after the Nobel Prize received by Roentgen (1901), in 1979 the same prize was awarded to Hounsfield and Cormack on the same part of the scientific front - for the creation of a computed tomograph. Nobel Prize for creating the device! The phenomenon is quite rare in science. And the whole point is that the capabilities of the method are quite comparable to the revolutionary discovery of Roentgen.

The disadvantage of the x-ray method is the flat image and the overall effect. With CT, the image of an object is mathematically reconstructed from a countless set of its projections. Such an object is a thin slice. At the same time, it is illuminated from all sides and its image is recorded by a huge number of highly sensitive sensors (several hundred). The received information is processed on a computer. CT detectors are very sensitive. They detect differences in the density of structures of less than one percent (with conventional radiography - 15-20%). From here, you can get images of various structures of the brain, liver, pancreas and a number of other organs.

Advantages of CT: 1) high resolution, 2) examination of the thinnest section - 3-5 mm, 3) the ability to quantify density from -1000 to + 1000 Hounsfield units.

Currently, spiral computed tomographs have appeared that provide examination of the entire body and obtain tomograms in normal operating mode in one second and image reconstruction time from 3 to 4 seconds. For the creation of these devices, scientists were awarded the Nobel Prize. Mobile CT scanners have also appeared.

Magnetic resonance imaging is based on nuclear magnetic resonance. Unlike an X-ray machine, a magnetic tomograph does not “examine” the body with rays, but forces the organs themselves to send radio signals, which the computer processes to form an image.

Work principles. The object is placed in a constant magnetic field, which is created by a unique electromagnet in the form of 4 huge rings connected together. On the couch, the patient is moved into this tunnel. A powerful constant electromagnetic field is turned on. In this case, the protons of hydrogen atoms contained in the tissues are oriented strictly along the lines of force (under normal conditions they are randomly oriented in space). Then the high-frequency electromagnetic field is turned on. Now the nuclei, returning to their original state (position), emit tiny radio signals. This is the NMR effect. The computer registers these signals and the distribution of protons and forms an image on a television screen.

Radio signals are not the same and depend on the location of the atom and its environment. Atoms in painful areas emit a radio signal that differs from the radiation of neighboring healthy tissues. The resolution of the devices is extremely high. For example, individual structures of the brain are clearly visible (stem, hemisphere, gray, white matter, ventricular system, etc.). Advantages of MRI over CT:

1) MP tomography is not associated with the risk of tissue damage, unlike X-ray examination.

2) Scanning with radio waves allows you to change the location of the section being studied in the body”; without changing the patient's position.

3) The image is not only transverse, but also in any other sections.

4) Resolution is higher than with CT.

Obstacles to MRI are metal bodies (clips after surgery, cardiac pacemakers, electrical neurostimulators)

Current trends in the development of radiation diagnostics

1. Improving methods based on computer technology

2. Expanding the scope of application of new high-tech methods - ultrasound, MRI, X-ray CT, PET.

4. Replacement of labor-intensive and invasive methods with less dangerous ones.

5. Maximum reduction of radiation exposure to patients and staff.

Comprehensive development of interventional radiology, integration with other medical specialties.

The first direction is a breakthrough in the field of computer technology, which made it possible to create a wide range of devices for digital digital radiography, ultrasound, MRI to the use of three-dimensional images.

One laboratory per 200-300 thousand population. It should preferably be placed in therapeutic clinics.

1. It is necessary to place the laboratory in a separate building, built according to a standard design with a security sanitary zone around it. It is forbidden to build children's institutions and catering units on the territory of the latter.

2. The radionuclide laboratory must have a certain set of premises (radiopharmaceutical storage, packaging, generator, washing, treatment room, sanitary inspection room).

3. Special ventilation is provided (five air changes when using radioactive gases), sewerage with a number of settling tanks in which waste of at least ten half-lives is kept.

4. Daily wet cleaning of the premises must be carried out.

In the coming years, and sometimes even today, the main place of work of a doctor will be a personal computer, on the screen of which information with electronic medical history data will be displayed.

The second direction is associated with the widespread use of CT, MRI, PET, and the development of ever new areas of their use. Not from simple to complex, but the choice of the most effective techniques. For example, detection of tumors, metastases of the brain and spinal cord - MRI, metastases - PET; renal colic - spiral CT.

The third direction is the widespread elimination of invasive methods and methods associated with high radiation exposure. In this regard, today myelography, pneumomediastinography, intravenous cholegraphy, etc. have practically disappeared. Indications for angiography are being reduced.

The fourth direction is the maximum reduction of doses of ionizing radiation due to: I) replacing X-ray emitters MRI, ultrasound, for example, when examining the brain and spinal cord, biliary tract, etc. But this must be done deliberately so that a situation does not happen similar to an X-ray examination of the gastrointestinal tract, where everything shifted to FGS, although for endophytic cancers more information is obtained from X-ray examination. Today, ultrasound cannot replace mammography. 2) maximum reduction of doses during the X-ray examinations themselves by eliminating duplication of images, improving technology, film, etc.

The fifth direction is the rapid development of interventional radiology and the widespread involvement of radiation diagnosticians in this work (angiography, puncture of abscesses, tumors, etc.).

Features of individual diagnostic methods at the present stage

In traditional radiology, the layout of X-ray machines has fundamentally changed - installation on three workstations (images, transillumination and tomography) is replaced by a remote-controlled one workstation. The number of special devices has increased (mammographs, angiography, dentistry, ward, etc.). Devices for digital radiography, URI, subtraction digital angiography, and photostimulating cassettes have become widespread. Digital and computer radiology has emerged and is developing, which leads to a reduction in examination time, the elimination of the darkroom process, the creation of compact digital archives, the development of teleradiology, and the creation of intra- and interhospital radiological networks.

Ultrasound technologies have been enriched with new programs for digital processing of echo signals, and Dopplerography for assessing blood flow is intensively developing. Ultrasound has become the main method in the study of the abdomen, heart, pelvis, and soft tissues of the extremities; the importance of the method in the study of the thyroid gland, mammary glands, and intracavitary studies is increasing.

In the field of angiography, interventional technologies are intensively developing (balloon dilatation, installation of stents, angioplasty, etc.)

In RCT, spiral scanning, multilayer CT, and CT angiography become dominant.

MRI has been enriched with open-type installations with a field strength of 0.3 - 0.5 T and with high intensity (1.7-3 OT), functional methods for studying the brain.

A number of new radiopharmaceuticals have appeared in radionuclide diagnostics, and PET (oncology and cardiology) has established itself in the clinic.

Telemedicine is emerging. Its task is electronic archiving and transmission of patient data over a distance.

The structure of radiation research methods is changing. Traditional X-ray examinations, testing and diagnostic fluorography, ultrasound are methods of primary diagnosis and are mainly focused on studying the organs of the thoracic and abdominal cavity, and the osteo-articular system. Specifying methods include MRI, CT, radionuclide studies, especially when examining bones, dentofacial area, head and spinal cord.

Currently, over 400 compounds of various chemical natures have been developed. The method is an order of magnitude more sensitive than laboratory biochemical studies. Today, radioimmunoassay is widely used in endocrinology (diagnosis diabetes mellitus), in oncology (search for cancer markers), in cardiology (diagnosis of myocardial infarction), in pediatrics (in case of impaired child development), in obstetrics and gynecology (infertility, impaired fetal development), in allergology, in toxicology, etc.

In industrialized countries, the main emphasis is now on organizing positron emission tomography (PET) centers in large cities, which, in addition to a positron emission tomograph, also includes a small-sized cyclotron for the on-site production of positron-emitting ultrashort-lived radionuclides. Where there are no small-sized cyclotrons, the isotope (F-18 with a half-life of about 2 hours) is obtained from their regional radionuclide production centers or generators (Rb-82, Ga-68, Cu-62) are used.

Currently, radionuclide research methods are also used for preventive purposes to identify hidden diseases. Thus, any headache requires a brain study with pertechnetate-Tc-99sh. This type of screening allows us to exclude tumors and areas of hemorrhage. A reduced kidney detected in childhood by scintigraphy should be removed to prevent malignant hypertension. A drop of blood taken from the child's heel allows you to determine the amount of thyroid hormones.

Methods of radionuclide research are divided into: a) research of a living person; b) examination of blood, secretions, excreta and other biological samples.

In vivo methods include:

1. Radiometry (of the whole body or part of it) - determination of the activity of a part of the body or organ. Activity is recorded as numbers. An example is the study of the thyroid gland and its activity.

2. Radiography (gammachronography) - on a radiograph or gamma camera, the dynamics of radioactivity is determined in the form of curves (hepatoradiography, radiorenography).

3. Gammatopography (on a scanner or gamma camera) - the distribution of activity in an organ, which allows one to judge the position, shape, size, and uniformity of drug accumulation.

4. Radioimmunoassay (radiocompetitive) - hormones, enzymes, medicines And so on. In this case, the radiopharmaceutical is introduced into a test tube, for example, with the patient’s blood plasma. The method is based on competition between a substance labeled with a radionuclide and its analogue in a test tube for complexing (combining) with a specific antibody. An antigen is a biochemical substance that needs to be determined (hormone, enzyme, drug). For analysis you must have: 1) the substance under study (hormone, enzyme); 2) its labeled analogue: the label is usually 1-125 with a half-life of 60 days or tritium with a half-life of 12 years; 3) a specific perceptive system, which is the subject of “competition” between the desired substance and its labeled analogue (antibody); 4) a separation system that separates bound radioactive substances from unbound ones (activated carbon, ion exchange resins, etc.).

RADIATION STUDY OF THE LUNG

The lungs are one of the most common objects of radiation research. The important role of x-ray examination in the study of the morphology of the respiratory organs and the recognition of various diseases is evidenced by the fact that the accepted classifications of many pathological processes are based on x-ray data (pneumonia, tuberculosis, lung cancer, sarcoidosis, etc.). Often hidden diseases such as tuberculosis, cancer, etc. are detected during screening fluorographic examinations. With the advent of computed tomography, the importance of X-ray examination of the lungs has increased. An important place in the study of pulmonary blood flow belongs to radionuclide research. Indications for radiation examination of the lungs are very wide (cough, sputum production, shortness of breath, fever, etc.).

Radiation examination allows you to diagnose the disease, clarify the localization and extent of the process, monitor the dynamics, monitor recovery, and detect complications.

The leading role in the study of the lungs belongs to X-ray examination. Among the research methods, fluoroscopy and radiography should be noted, which allow assessing both morphological and functional changes. The methods are simple and not burdensome for the patient, highly informative, and publicly available. Typically, survey images are taken in frontal and lateral projections, targeted images, superexposed (super-rigid, sometimes replacing tomography). To identify fluid accumulation in the pleural cavity, photographs are taken in a later position on the affected side. In order to clarify the details (the nature of the contours, the homogeneity of the shadow, the condition of the surrounding tissues, etc.), tomography is performed. For mass examination of the chest organs, fluorography is used. Contrast methods include bronchography (to detect bronchiectasis), angiopulmonography (to determine the extent of the process, for example in lung cancer, to detect thromboembolism of the branches of the pulmonary artery).

X-ray anatomy. Analysis of X-ray data of the chest organs is carried out in a certain sequence. Evaluated:

1) image quality (correct placement of the patient, degree of film exposure, capture volume, etc.),

2) the condition of the chest as a whole (shape, size, symmetry of the pulmonary fields, position of the mediastinal organs),

3) the condition of the skeleton that forms the chest (shoulder girdle, ribs, spine, collarbones),

4) soft tissues (skin strip over the collarbones, shadow and sternoclavicular muscles, mammary glands),

5) state of the diaphragm (position, shape, contours, sinuses),

6) condition of the roots of the lungs (position, shape, width, condition of the outer skin, structure),

7) state of the pulmonary fields (size, symmetry, pulmonary pattern, transparency),

8) condition of the mediastinal organs. It is necessary to study the bronchopulmonary segments (name, location).

X-ray semiotics of lung diseases is extremely diverse. However, this diversity can be reduced to several groups of characteristics.

1. Morphological characteristics:

1) dimming

2) enlightenment

3) a combination of darkening and brightening

4) changes in pulmonary pattern

5) root pathology

2. Functional characteristics:

1) change in the transparency of the lung tissue in the inhalation and exhalation phases

2) mobility of the diaphragm during breathing

3) paradoxical movements of the diaphragm

4) movement of the median shadow in the inhalation and exhalation phases. Having detected pathological changes, it is necessary to decide what disease they are caused by. It is usually impossible to do this “at first glance” if there are no pathognomonic symptoms (needle, badge, etc.). The task is made easier if you isolate the radiological syndrome. The following syndromes are distinguished:

1. Total or subtotal blackout syndrome:

1) intrapulmonary opacities (pneumonia, atelectasis, cirrhosis, hiatal hernia),

2) extrapulmonary opacities (exudative pleurisy, moorings). The distinction is based on two features: the structure of the darkening and the position of the mediastinal organs.

For example, the shadow is homogeneous, the mediastinum is shifted towards the lesion - atelectasis; the shadow is homogeneous, the heart is shifted to the opposite side - exudative pleurisy.

2. Restricted dimming syndrome:

1) intrapulmonary (lobe, segment, subsegment),

2) extrapulmonary (pleural effusion, changes in the ribs and mediastinal organs, etc.).

Limited darkening is the most difficult way of diagnostic decoding (“oh, not lungs - these lungs!”). They occur in pneumonia, tuberculosis, cancer, atelectasis, thromboembolism of the branches of the pulmonary artery, etc. Consequently, the detected shadow should be assessed in terms of position, shape, size, nature of the contours, intensity and homogeneity, etc.

Round (spherical) darkening syndrome - in the form of one or several foci that have a more or less rounded shape measuring more than one cm. They can be homogeneous or heterogeneous (due to decay and calcification). A rounded shadow must be determined in two projections.

According to localization, rounded shadows can be:

1) intrapulmonary (inflammatory infiltrate, tumor, cysts, etc.) and

2) extrapulmonary, originating from the diaphragm, chest wall, mediastinum.

Today there are about 200 diseases that cause a round shadow in the lungs. Most of them are rare.

Therefore, most often it is necessary to carry out differential diagnosis with the following diseases:

1) peripheral lung cancer,

2) tuberculoma,

3) benign tumor,

5) lung abscess and foci of chronic pneumonia,

6) solid metastasis. These diseases account for up to 95% of rounded shadows.

When analyzing a round shadow, one should take into account the localization, structure, nature of the contours, the state of the lung tissue around, the presence or absence of a “path” to the root, etc.

4.0 focal (focal-like) darkenings are round or irregularly shaped formations with a diameter of 3 mm to 1.5 cm. Their nature is varied (inflammatory, tumor, cicatricial changes, areas of hemorrhage, atelectasis, etc.). They can be single, multiple or disseminated and vary in size, location, intensity, nature of contours, and changes in the pulmonary pattern. So, when localization of foci in the area of ​​the apex of the lung, subclavian space, one should think about tuberculosis. Uneven contours usually characterize inflammatory processes, peripheral cancer, foci of chronic pneumonia, etc. The intensity of the foci is usually compared with the pulmonary pattern, rib, and median shadow. In differential diagnosis, dynamics (increase or decrease in the number of lesions) are also taken into account.

Focal shadows are most often found in tuberculosis, sarcoidosis, pneumonia, metastases of malignant tumors, pneumoconiosis, pneumosclerosis, etc.

5. Dissemination syndrome - spread of multiple focal shadows in the lungs. Today there are over 150 diseases that can cause this syndrome. The main delimiting criteria are:

1) sizes of lesions - miliary (1-2 mm), small (3-4 mm), medium (5-8 mm) and large (9-12 mm),

2) clinical manifestations,

3) preferential localization,

4) dynamics.

Miliary dissemination is characteristic of acute disseminated (miliary) tuberculosis, nodular pneumoconiosis, sarcoidosis, carcinomatosis, hemosiderosis, histiocytosis, etc.

When assessing the X-ray picture, one should take into account the localization, uniformity of dissemination, the state of the pulmonary pattern, etc.

Dissemination with lesions larger than 5 mm reduces the diagnostic task to distinguishing between focal pneumonia, tumor dissemination, and pneumosclerosis.

Diagnostic errors in dissemination syndrome are quite frequent and amount to 70-80%, and therefore adequate therapy is delayed. Currently, disseminated processes are divided into: 1) infectious (tuberculosis, mycoses, parasitic diseases, HIV infection, respiratory distress syndrome), 2) non-infectious (pneumoconiosis, allergic vasculitis, drug changes, radiation consequences, post-transplant changes, etc.).

About half of all disseminated lung diseases are related to processes of unknown etiology. For example, idiopathic fibrosing alveolitis, sarcoidosis, histiocytosis, idiopathic hemosiderosis, vasculitis. In some systemic diseases, dissemination syndrome is also observed (rheumatoid diseases, liver cirrhosis, hemolytic anemia, heart disease, kidney disease, etc.).

Recently, X-ray computed tomography (XCT) has provided great assistance in the differential diagnosis of disseminated processes in the lungs.

6. Clearance syndrome. Clearances in the lungs are divided into limited (cavity formations - ring-shaped shadows) and diffuse. Diffuse, in turn, are divided into structureless (pneumothorax) and structural (pulmonary emphysema).

Ring shadow (clearance) syndrome manifests itself in the form of a closed ring (in two projections). If a ring-shaped clearing is detected, it is necessary to establish the location, wall thickness, and condition of the lung tissue around. Hence, they distinguish:

1) thin-walled cavities, which include bronchial cysts, racemose bronchiectasis, post-pneumonic (false) cysts, sanitized tuberculous cavities, emphysematous bullae, cavities with staphylococcal pneumonia;

2) unevenly thick cavity walls (disintegrating peripheral cancer);

3) uniformly thick walls of the cavity (tuberculous cavities, lung abscess).

7. Pathology of the pulmonary pattern. The pulmonary pattern is formed by the branches of the pulmonary artery and appears as linear shadows located radially and not reaching the costal margin by 1-2 cm. The pathologically altered pulmonary pattern can be enhanced or depleted.

1) Strengthening of the pulmonary pattern manifests itself in the form of coarse additional stringy formations, often randomly located. Often it becomes loopy, cellular, and chaotic.

Strengthening and enrichment of the pulmonary pattern (per unit area of ​​lung tissue there is an increase in the number of elements of the pulmonary pattern) is observed with arterial congestion of the lungs, congestion in the lungs, and pneumosclerosis. Strengthening and deformation of the pulmonary pattern is possible:

a) small-cell type and b) large-cell type (pneumosclerosis, bronchiectasis, cystic lung).

Strengthening of the pulmonary pattern can be limited (pneumofibrosis) and diffuse. The latter occurs in fibrosing alveolitis, sarcoidosis, tuberculosis, pneumoconiosis, histiocytosis X, tumors (cancerous lymphangitis), vasculitis, radiation injuries, etc.

Depletion of the pulmonary pattern. At the same time, there are fewer elements of the pulmonary pattern per unit area of ​​the lung. Depletion of the pulmonary pattern is observed with compensatory emphysema, underdevelopment of the arterial network, valve blockage of the bronchus, progressive pulmonary dystrophy (disappearing lung), etc.

The disappearance of the pulmonary pattern is observed with atelectasis and pneumothorax.

8. Pathology of roots. There are normal roots, infiltrated roots, stagnant roots, roots with enlarged lymph nodes and fibrosis-unchanged roots.

A normal root is located from 2 to 4 ribs, has a clear outer contour, the structure is heterogeneous, the width does not exceed 1.5 cm.

The differential diagnosis of pathologically altered roots takes into account the following points:

1) one or two sided lesions,

2) changes in the lungs,

3) clinical picture (age, ESR, changes in blood, etc.).

The infiltrated root appears expanded, structureless with an unclear outer contour. Occurs in inflammatory lung diseases and tumors.

Stagnant roots look exactly the same. However, the process is two-sided and there are usually changes in the heart.

Roots with enlarged lymph nodes are structureless, expanded, with a clear outer boundary. Sometimes there is polycyclicity, a symptom of “backstage”. Occurs in systemic blood diseases, metastases of malignant tumors, sarcoidosis, tuberculosis, etc.

The fibrously changed root is structural, usually displaced, often has calcified lymph nodes and is usually observed fibrotic changes in the lungs.

9. The combination of darkening and clearing is a syndrome that is observed in the presence of a decay cavity of a purulent, caseous or tumor nature. Most often it occurs in the cavitary form of lung cancer, tuberculosis cavity, disintegrating tuberculosis infiltrate, lung abscess, suppurating cysts, bronchiectasis, etc.

10. Pathology of the bronchi:

1) violation of bronchial obstruction due to tumors and foreign bodies. There are three degrees of bronchial obstruction (hypoventilation, ventilatory obstruction, atelectasis),

2) bronchiectasis (cylindrical, saccular and mixed bronchiectasis),

3) deformation of the bronchi (with pneumosclerosis, tuberculosis and other diseases).

RADIATION STUDY OF THE HEART AND GREAT VESSELS

Radiation diagnostics of diseases of the heart and large vessels has come a long way in its development, full of triumph and drama.

The great diagnostic role of X-ray cardiology has never been in doubt. But this was her youth, a time of loneliness. In the last 15-20 years, there has been a technological revolution in diagnostic radiology. Thus, in the 70s, ultrasound devices were created that made it possible to look inside the cavities of the heart and study the condition of the drip apparatus. Later, dynamic scintigraphy made it possible to judge the contractility of individual segments of the heart and the nature of blood flow. In the 80s, computerized methods of obtaining images entered the practice of cardiology: digital coronary and ventriculography, CT, MRI, cardiac catheterization.

Recently, the opinion has begun to spread that traditional X-ray examination of the heart has become obsolete as a technique for examining cardiac patients, since the main methods for examining the heart are ECG, ultrasound, and MRI. However, in assessing pulmonary hemodynamics, which reflects the functional state of the myocardium, X-ray examination retains its advantages. It not only allows you to identify changes in the vessels of the pulmonary circulation, but also provides an idea of ​​the chambers of the heart that led to these changes.

Thus, radiation examination of the heart and large vessels includes:

non-invasive methods (fluoroscopy and radiography, ultrasound, CT, MRI)

invasive methods (angiocardiography, ventriculography, coronary angiography, aortography, etc.)

Radionuclide methods make it possible to judge hemodynamics. Consequently, today radiology diagnostics in cardiology is experiencing its maturity.

X-ray examination of the heart and great vessels.

Method value. X-ray examination is part of the general clinical examination of the patient. The goal is to establish the diagnosis and nature of hemodynamic disorders (the choice of treatment method depends on this - conservative, surgical). In connection with the use of URI in combination with cardiac catheterization and angiography, broad prospects have opened up in the study of circulatory disorders.

Research methods

1) Fluoroscopy is the technique with which the study begins. It allows you to get an idea of ​​the morphology and give a functional description of the shadow of the heart as a whole and its individual cavities, as well as large vessels.

2) Radiography objectifies the morphological data obtained during fluoroscopy. Its standard projections:

a) front straight

b) right anterior oblique (45°)

c) left anterior oblique (45°)

d) left side

Signs of oblique projections:

1) Right oblique - triangular shape of the heart, gas bubble of the stomach in front, along the posterior contour on top is the ascending aorta, the left atrium, below - the right atrium; along the anterior contour, the aorta is determined from above, then there is the cone of the pulmonary artery and, below, the arch of the left ventricle.

2) Left oblique - oval in shape, the gastric bladder is behind, between the spine and the heart, the bifurcation of the trachea is clearly visible and all parts of the thoracic aorta are identified. All chambers of the heart open onto the circuit - the atrium is on top, the ventricles are below.

3) Examination of the heart with a contrasted esophagus (the esophagus is normally located vertically and is adjacent to the arch of the left atrium for a considerable length, which allows one to determine its condition). With enlargement of the left atrium, there is a displacement of the esophagus along an arc of large or small radius.

4) Tomography - clarifies the morphological features of the heart and large vessels.

5) X-ray kymography, electrokymography - methods of functional study of myocardial contractility.

6) X-ray cinematography - filming the work of the heart.

7) Catheterization of the cavities of the heart (determining blood oxygen saturation, measuring pressure, determining the minute and stroke volume of the heart).

8) Angiocardiography more accurately determines anatomical and hemodynamic disorders in heart defects (especially congenital ones).

X-ray data study plan

1. Study of the skeleton of the chest (attention is drawn to anomalies in the development of the ribs, spine, curvature of the latter, “abnormalities” of the ribs during coarctation of the aorta, signs of pulmonary emphysema, etc.).

2. Study of the diaphragm (position, mobility, fluid accumulation in the sinuses).

3. Study of the hemodynamics of the pulmonary circulation (the degree of bulging of the pulmonary artery cone, the condition of the roots of the lungs and pulmonary pattern, the presence of pleural lines and Kerley lines, focally infiltrative shadows, hemosiderosis).

4. X-ray morphological study of the cardiovascular shadow

a) position of the heart (oblique, vertical and horizontal).

b) heart shape (oval, mitral, triangular, aortic)

c) heart size. On the right, 1-1.5 cm from the edge of the spine, on the left, 1-1.5 cm not reaching the midclavicular line. We judge the upper limit by the so-called waist of the heart.

5. Determination of the functional characteristics of the heart and large vessels (pulsation, “yoke” symptom, systolic displacement of the esophagus, etc.).

Acquired heart defects

Relevance. The introduction of surgical treatment of acquired defects into surgical practice required radiologists to clarify them (stenosis, insufficiency, their predominance, the nature of hemodynamic disturbances).

Causes: almost all acquired defects are a consequence of rheumatism, rarely septic endocarditis; collagenosis, trauma, atherosclerosis, syphilis can also lead to heart disease.

Failure mitral valve occurs more often than stenosis. This causes the valve flaps to shrink. Hemodynamic disturbances are associated with the absence of a period of closed valves. During ventricular systole, part of the blood returns to the left atrium. The latter is expanding. During diastole, a larger amount of blood returns to the left ventricle, which is why the latter has to work harder and hypertrophies. With a significant degree of insufficiency, the left atrium expands sharply, its wall sometimes becomes thinner to a thin sheet through which blood can be seen.

Violation of intracardiac hemodynamics with this defect is observed when 20-30 ml of blood is thrown into the left atrium. For a long time, no significant changes in circulatory disturbances in the pulmonary circle were observed. Congestion in the lungs occurs only in advanced stages - with left ventricular failure.

X-ray semiotics.

The shape of the heart is mitral (the waist is flattened or bulging). The main symptom is an enlargement of the left atrium, sometimes extending onto the right contour in the form of an additional third arch (symptom of “crossover”). The degree of enlargement of the left atrium is determined in the first oblique position in relation to the spine (1-III).

The contrasted esophagus deviates along an arc of large radius (more than 6-7 cm). There is an expansion of the tracheal bifurcation angle (up to 180) and a narrowing of the lumen of the right main bronchus. The third arc along the left contour prevails over the second. The aorta is of normal size and fills well. Among the X-ray functional symptoms, the most noteworthy are the “yoke” symptom (systolic expansion), systolic displacement of the esophagus, and Roesler’s symptom (transfer pulsation of the right root.

After surgery, all changes are eliminated.

Stenosis of the left mitral valve (fusion of the leaflets).

Hemodynamic disturbances are observed with a decrease in the mitral orifice by more than half (about one sq. cm). Normally, the mitral orifice is 4-6 sq. see, pressure in the left atrium cavity is 10 mm Hg. With stenosis, the pressure increases by 1.5-2 times. The narrowing of the mitral orifice prevents the expulsion of blood from the left atrium into the left ventricle, the pressure in which rises to 15-25 mm Hg, which complicates the outflow of blood from the pulmonary circulation. The pressure in the pulmonary artery increases (this is passive hypertension). Later, active hypertension is observed as a result of irritation of the baroreceptors of the endocardium of the left atrium and the mouth of the pulmonary veins. As a result, a reflex spasm of arterioles and larger arteries develops - the Kitaev reflex. This is the second barrier to blood flow (the first is the narrowing of the mitral valve). This increases the load on the right ventricle. Prolonged spasm of the arteries leads to cardiogenic pulmonary fibrosis.

Clinic. Weakness, shortness of breath, cough, hemoptysis. X-ray semiotics. The earliest and most characteristic sign is a violation of the hemodynamics of the pulmonary circulation - congestion in the lungs (expansion of the roots, increased pulmonary pattern, Kerley lines, septal lines, hemosiderosis).

X-ray symptoms. The heart has a mitral configuration due to the sharp bulging of the pulmonary artery cone (the second arch predominates over the third). There is hypertrophy of the left atrium. The coitrasted esophagus is deviated along a small radius arc. There is an upward displacement of the main bronchi (more than the left one), an increase in the angle of tracheal bifurcation. The right ventricle is enlarged, the left one is usually small. The aorta is hypoplastic. Heart contractions are calm. Calcification of the valves is often observed. During catheterization, an increase in pressure is noted (1-2 times higher than normal).

Aortic valve insufficiency

Hemodynamic disturbances with this heart defect are reduced to incomplete closure of the aortic valves, which during diastole leads to the return of 5 to 50% of the blood to the left ventricle. The result is dilation of the left ventricle due to hypertrophy. At the same time, the aorta expands diffusely.

The clinical picture includes palpitations, heart pain, fainting and dizziness. The difference in systolic and diastolic pressures is large (systolic pressure is 160 mm Hg, diastolic pressure is low, sometimes reaching 0). The carotid “dancing” symptom, Mussy’s symptom, and pallor of the skin are observed.

X-ray semiotics. An aortic configuration of the heart (deep, emphasized waist), enlargement of the left ventricle, and rounding of its apex are observed. All parts of the thoracic aorta expand evenly. Of the X-ray functional signs, noteworthy is the increase in the amplitude of heart contractions and increased pulsation of the aorta (pulse celer et altus). The degree of aortic valve insufficiency is determined by angiography (grade 1 - a narrow stream, in stage 4 - the entire cavity of the left ventricle is co-traced in diastole).

Aortic stenosis (narrowing more than 0.5-1 cm 2, normal 3 cm 2).

Hemodynamic disturbances result in obstructed blood outflow from the left ventricle into the aorta, which leads to prolongation of systole and increased pressure in the cavity of the left ventricle. The latter sharply hypertrophies. With decompensation, congestion occurs in the left atrium, and then in the lungs, then in the systemic circulation.

At the clinic, people notice heart pain, dizziness, and fainting. There is systolic tremor, pulse parvus et tardus. The defect remains compensated for a long time.

X-ray semiotics. Left ventricular hypertrophy, rounding and lengthening of its arch, aortic configuration, poststenotic dilation of the aorta (its ascending part). Heart contractions are tense and reflect difficult ejection of blood. Calcification of the aortic valves is quite common. With decompensation, mitralization of the heart develops (the waist is smoothed due to an enlargement of the left atrium). Angiography reveals narrowing of the aortic opening.

Pericarditis

Etiology: rheumatism, tuberculosis, bacterial infections.

1. fibrous pericarditis

2. effusion (exudative) pericarditis Clinic. Pain in the heart, pallor, cyanosis, shortness of breath, swelling of the veins of the neck.

The diagnosis of dry pericarditis is usually made based on clinical findings (pericardial friction rub). When fluid accumulates in the pericardial cavity (the minimum amount that can be detected x-ray is 30-50 ml), a uniform increase in the size of the heart is noted, the latter taking on a trapezoidal shape. The arcs of the heart are smoothed and not differentiated. The heart is widely adjacent to the diaphragm, its diameter prevails over its length. The cardiophrenic angles are sharp, the vascular bundle is shortened, and there is no congestion in the lungs. Displacement of the esophagus is not observed, cardiac pulsation is sharply weakened or absent, but preserved in the aorta.

Adhesive or compressive pericarditis is the result of fusion between both layers of the pericardium, as well as between the pericardium and the mediastinal pleura, which makes it difficult for the heart to contract. With calcification - “shell heart”.

Myocarditis

There are:

1. infectious-allergic

2. toxic-allergic

3. idiopathic myocarditis

Clinic. Pain in the heart, increased pulse rate with weak filling, rhythm disturbance, signs of heart failure. At the apex of the heart there is a systolic murmur, muffled heart sounds. Noticeable congestion in the lungs.

The X-ray picture is due to myogenic dilatation of the heart and signs of decreased contractile function of the myocardium, as well as a decrease in the amplitude of heart contractions and their increase in frequency, which ultimately leads to stagnation in the pulmonary circulation. The main X-ray sign is enlargement of the ventricles of the heart (mainly the left), trapezoidal shape of the heart, the atria are enlarged to a lesser extent than the ventricles. The left atrium may extend onto the right circuit, deviation of the contrasted esophagus is possible, heart contractions are shallow and accelerated. When left ventricular failure occurs, stagnation appears in the lungs due to obstruction of blood outflow from the lungs. With the development of right ventricular failure, the superior vena cava expands and edema appears.

X-RAY STUDY OF THE GASTROINTESTINAL TRACT

Diseases of the digestive system occupy one of the first places in the overall structure of morbidity, admission and hospitalization. Thus, about 30% of the population have complaints from the gastrointestinal tract, 25.5% of patients are admitted to hospitals for emergency care, and pathology of the digestive organs accounts for 15% of overall mortality.

A further increase in diseases is predicted, mainly those in the development of which stress, dyskinetic, immunological and metabolic mechanisms play a role (peptic ulcer, colitis, etc.). The course of the disease becomes more severe. Often diseases of the digestive organs are combined with each other and diseases of other organs and systems; damage to the digestive organs is possible due to systemic diseases (scleroderma, rheumatism, diseases of the hematopoietic system, etc.).

The structure and function of all parts of the digestive canal can be studied using radiation methods. Optimal radiation diagnostic techniques have been developed for each organ. Establishing indications for radiation examination and its planning are carried out on the basis of anamnestic and clinical data. Endoscopic examination data is also taken into account, allowing one to examine the mucous membrane and obtain material for histological examination.

X-ray examination of the digestive canal takes special place in X-ray diagnostics:

1) recognition of diseases of the esophagus, stomach and colon is based on a combination of transillumination and photography. Here the importance of the experience of a radiologist is most clearly demonstrated,

2) examination of the gastrointestinal tract requires preliminary preparation (examination on an empty stomach, use of cleansing enemas, laxatives).

3) the need for artificial contrast (an aqueous suspension of barium sulfate, the introduction of air into the stomach cavity, oxygen into the abdominal cavity, etc.),

4) examination of the esophagus, stomach and colon is carried out mainly “from the inside” from the mucous membrane.

X-ray examination, due to its simplicity, universal accessibility and high efficiency, allows:

1) recognize most diseases of the esophagus, stomach and colon,

2) monitor the results of treatment,

3) carry out dynamic observations for gastritis, peptic ulcer and other diseases,

4) screen patients (fluorography).

Methods for preparing barium suspension. The success of X-ray examination depends, first of all, on the method of preparing the barium suspension. Requirements for an aqueous suspension of barium sulfate: maximum fineness, mass volume, adhesiveness and improvement of organoleptic properties. There are several ways to prepare barium suspension:

1. Boiling at the rate of 1:1 (per 100.0 BaS0 4 100 ml of water) for 2-3 hours.

2. Use of “Voronezh” type mixers, electric mixers, ultrasonic units, micro-pulverizers.

3. Recently, in order to improve conventional and double contrast, they have been trying to increase the mass volume of barium sulfate and its viscosity through various additives, such as distilled glycerin, polyglucin, sodium citrate, starch, etc.

4. Ready-made forms of barium sulfate: sulfobar and other proprietary preparations.

X-ray anatomy

The esophagus is a hollow tube 20-25 cm long, 2-3 cm wide. The contours are smooth and clear. 3 physiological constrictions. Sections of the esophagus: cervical, thoracic, abdominal. Folds - about longitudinal ones in the amount of 3-4. Projections of the study (direct, right and left oblique positions). The speed of movement of barium suspension through the esophagus is 3-4 seconds. Ways to slow down are to study in a horizontal position and take a thick paste-like mass. Research phases: tight filling, study of pneumorelief and mucosal relief.

Stomach. When analyzing the x-ray picture, it is necessary to have an idea of ​​the nomenclature of its various sections (cardiac, subcardial, body of the stomach, sinus, antrum, pyloric section, gastric vault).

The shape and position of the stomach depend on the constitution, gender, age, tone, and position of the person being examined. There is a hook-shaped stomach (vertically located stomach) in asthenics and a horn (horizontally located stomach) in hypersthenic individuals.

The stomach is located mostly in the left hypochondrium, but can move within a very wide range. The most variable position of the lower border (normally 2-4 cm above the crest of the iliac bones, but in thin people it is much lower, often above the entrance to the pelvis). The most fixed sections are the cardiac and pyloric. The width of the retrogastric space is of greater importance. Normally, it should not exceed the width of the lumbar vertebral body. During volumetric processes, this distance increases.

The relief of the gastric mucosa is formed by folds, interfold spaces and gastric fields. Folds are represented by stripes of enlightenment 0.50.8 cm wide. However, their sizes are highly variable and depend on gender, constitution, stomach tone, degree of distension, and mood. Gastric fields are defined as small filling defects on the surface of the folds due to elevations, at the top of which the ducts of the gastric glands open; their sizes normally do not exceed 3 mm and look like a thin mesh (the so-called thin relief of the stomach). With gastritis, it becomes rough, reaching a size of 5-8mm, resembling a “cobblestone street”.

Secretion of the gastric glands on an empty stomach is minimal. Normally, the stomach should be empty.

Stomach tone is the ability to embrace and hold a sip of barium suspension. There are normotonic, hypertonic, hypotonic and atonic stomachs. With normal tone, the barium suspension drops slowly, with low tone it drops quickly.

Peristalsis is the rhythmic contraction of the stomach walls. Attention is paid to rhythm, duration of individual waves, depth and symmetry. There are deep, segmenting, medium, superficial peristalsis and its absence. To stimulate peristalsis, it is sometimes necessary to resort to a morphine test (s.c. 0.5 ml of morphine).

Evacuation. During the first 30 minutes, half of the ingested aqueous suspension of barium sulfate is evacuated from the stomach. The stomach is completely freed from barium suspension within 1.5 hours. In a horizontal position on the back, emptying slows down sharply, while on the right side it accelerates.

Palpation of the stomach is normally painless.

The duodenum has the shape of a horseshoe, its length is from 10 to 30 cm, its width is from 1.5 to 4 cm. It consists of a bulb, upper horizontal, descending and lower horizontal parts. The pattern of the mucous membrane is feathery, inconsistent due to the Kerckring folds. In addition, there are small and

greater curvature, medial and lateral recesses, as well as the anterior and posterior walls of the duodenum.

Research methods:

1) usual classical examination (during examination of the stomach)

2) study under conditions of hypotension (probe and tubeless) using atropine and its derivatives.

Similarly, we study small intestine(ileum and jejunum).

X-ray semiotics of diseases of the esophagus, stomach, colon (main syndromes)

X-ray symptoms of diseases of the digestive tract are extremely diverse. Its main syndromes:

1) change in the position of the organ (dislocation). For example, displacement of the esophagus by enlarged lymph nodes, a tumor, a cyst, the left atrium, displacement due to atelectasis, pleurisy, etc. The stomach and intestines are displaced by an enlarged liver, hiatal hernia, etc.;

2) deformation. Stomach in the form of a pouch, snail, retort, hourglass; duodenum - a trefoil-shaped bulb;

3) change in size: increase (achalasia of the esophagus, stenosis of the pyloroduodenal zone, Hirschsprung’s disease, etc.), decrease (infiltrating form of gastric cancer),

4) narrowing and expansion: diffuse (achalasia of the esophagus, gastric stenosis, intestinal obstruction, etc., local (tumor, scar, etc.);

5) filling defect. Usually determined by tight filling due to a space-occupying formation (exophytically growing tumor, foreign bodies, bezoars, fecal stone, food debris and

6) “niche” symptom - is the result of ulceration of the wall during an ulcer, tumor (cancer). A “niche” is distinguished on the contour in the form of a diverticulum-like formation and on the relief in the form of a “stagnant spot”;

7) changes in the folds of the mucosa (thickening, breakage, rigidity, convergence, etc.);

8) rigidity of the wall during palpation and inflation (the latter does not change);

9) change in peristalsis (deep, segmenting, superficial, lack of peristalsis);

10) pain on palpation).

Diseases of the esophagus

Foreign bodies. Research methodology (candling, survey photographs). The patient takes 2-3 sips of a thick barium suspension, then 2-3 sips of water. If a foreign body is present, traces of barium remain on its upper surface. Pictures are taken.

Achalasia (inability to relax) is a disorder of the innervation of the esophagogastric junction. X-ray semiotics: clear, even contours of narrowing, the “writing pen” symptom, pronounced suprastenotic expansion, elasticity of the walls, periodic “dropping” of barium suspension into the stomach, absence of a gas bubble of the stomach and the duration of the benign course of the disease.

Esophageal carcinoma. In an exophytically growing form of the disease, X-ray semiotics is characterized by 3 classic signs: filling defect, malignant relief, wall rigidity. In the infiltrative form, there is rigidity of the wall, uneven contours, and changes in the relief of the mucous membrane. It should be differentiated from cicatricial changes after burns, varicose veins, and cardiospasm. With all these diseases, peristalsis (elasticity) of the walls of the esophagus is preserved.

Stomach diseases

Stomach cancer. In men it ranks first in the structure of malignant tumors. In Japan it is a national catastrophe; in the USA there is a downward trend in the disease. The predominant age is 40-60 years.

Classification. The most common division of stomach cancer is:

1) exophytic forms (polypoid, mushroom-shaped, cauliflower-shaped, cup-shaped, plaque-shaped form with and without ulceration),

2) endophytic forms (ulcerative-infiltrative). The latter account for up to 60% of all gastric cancers,

3) mixed forms.

Stomach cancer metastasizes to the liver (28%), retroperitoneal lymph nodes (20%), peritoneum (14%), lungs (7%), bones (2%). Most often localized in the antrum (over 60%) and in upper sections stomach (about 30%).

Clinic. Cancer often masquerades as gastritis, peptic ulcers, or cholelithiasis for years. Hence, for any gastric discomfort, X-ray and endoscopic examination is indicated.

X-ray semiotics. There are:

1) general signs (filling defect, malignant or atypical relief of the mucosa, absence of peristoglytics), 2) specific signs (in exophytic forms - a symptom of breakage of folds, flow around, splashing, etc.; in endfit forms - straightening of the lesser curvature, unevenness of the contour, deformation of the stomach; with total damage - a symptom of microgastrium.). In addition, with infiltrative forms, the filling defect is usually poorly expressed or absent, the relief of the mucous membrane almost does not change, the symptom of flat concave arcs (in the form of waves along the lesser curvature), the symptom of Gaudek's steps, is often observed.

X-ray semiotics of gastric cancer also depends on the location. When the tumor is localized in the gastric outlet, the following is noted:

1) elongation of the pyloric region by 2-3 times, 2) conical narrowing of the pyloric region occurs, 3) a symptom of undermining of the base of the pyloric region is observed 4) dilation of the stomach.

With cancer of the upper section (these are cancers with a long “silent” period) the following occur: 1) the presence of an additional shadow against the background of a gas bubble,

2) lengthening of the abdominal esophagus,

3) destruction of the mucosal relief,

4) the presence of edge defects,

5) flow symptom - “deltas”,

6) splashing symptom,

7) blunting of the Hiss angle (normally it is acute).

Cancers of the greater curvature are prone to ulceration - deep in the form of a well. However, any benign tumor in this area is prone to ulceration. Therefore, one must be careful with the conclusion.

Modern radiodiagnosis of gastric cancer. Recently, the number of cancers in the upper parts of the stomach has increased. Among all methods of radiological diagnostics, X-ray examination with tight filling remains the basic one. It is believed that diffuse forms of cancer today account for from 52 to 88%. In this form, cancer spreads predominantly intramural for a long time (from several months to one year or more) with minimal changes on the surface of the mucosa. Hence, endoscopy is often ineffective.

The leading radiological signs of intramural growing cancer should be considered uneven contour of the wall with tight filling (often one portion of barium suspension is not enough) and its thickening at the site of tumor infiltration with double contrast for 1.5 - 2.5 cm.

Due to the small extent of the lesion, peristalsis is often blocked by neighboring areas. Sometimes diffuse cancer manifests itself as a sharp hyperplasia of the folds of the mucosa. Often the folds converge or go around the affected area, resulting in the effect of no folds - (bald space) with the presence of a small barium spot in the center, caused not by ulceration, but by depression of the stomach wall. In these cases, methods such as ultrasound, CT, and MRI are useful.

Gastritis. Recently, in the diagnosis of gastritis, there has been a shift in emphasis towards gastroscopy with biopsy of the gastric mucosa. However, X-ray examination occupies an important place in the diagnosis of gastritis due to its accessibility and simplicity.

Modern recognition of gastritis is based on changes in the subtle relief of the mucous membrane, but double endogastric contrast is necessary to identify it.

Research methodology. 15 minutes before the test, 1 ml of a 0.1% atropine solution is injected subcutaneously or 2-3 aeron tablets are given (under the tongue). Then the stomach is inflated with a gas-forming mixture, followed by the intake of 50 ml of an aqueous suspension of barium sulfate in the form of an infusion with special additives. The patient is placed in a horizontal position and 23 rotational movements are made, followed by taking pictures on the back and in oblique projections. Then the usual examination is carried out.

Taking into account radiological data, several types of changes in the fine relief of the gastric mucosa are distinguished:

1) finely reticulated or granular (areolas 1-3 mm),

2) modular - (areola size 3-5 mm),

3) coarse nodular - (the size of the areolas is more than 5 mm, the relief is in the form of a “cobblestone street”). In addition, in the diagnosis of gastritis, such signs as the presence of fluid on an empty stomach, rough relief of the mucous membrane, diffuse pain on palpation, pyloric spasm, reflux, etc. are taken into account.

Benign tumors. Among them, polyps and leiomyomas are of greatest practical importance. A single polyp with tight filling is usually defined as a round filling defect with clear, even contours measuring 1-2 cm. Folds of the mucosa bypass the filling defect or the polyp is located on the fold. The folds are soft, elastic, palpation is painless, peristalsis is preserved. Leiomyomas differ from the X-ray semiotics of polyps in the preservation of mucosal folds and significant size.

Bezoars. It is necessary to distinguish between stomach stones (bezoars) and foreign bodies (swallowed bones, fruit pits, etc.). The term bezoar is associated with the name of a mountain goat, in whose stomach stones from licked wool were found.

For several millennia, the stone was considered an antidote and was valued higher than gold, as it supposedly brings happiness, health, and youth.

The nature of stomach bezoars is different. The most common:

1) phytobezoars (75%). Formed when eating a large amount of fruits containing a lot of fiber (unripe persimmon, etc.),

2) sebobezoars - occur when eating large amounts of fat with a high melting point (lamb fat),

3) trichobezoars - found in people who have the bad habit of biting off and swallowing hair, as well as in people caring for animals,

4) pixobesoars - the result of chewing resins, gum, gum,

5) shellac-bezoars - when using alcohol substitutes (alcohol varnish, palette, nitro varnish, nitro glue, etc.),

6) bezoars can occur after vagotomies,

7) bezoars consisting of sand, asphalt, starch and rubber are described.

Bezoars usually occur clinically under the guise of a tumor: pain, vomiting, weight loss, palpable swelling.

X-ray bezoars are defined as a filling defect with uneven contours. Unlike cancer, the filling defect shifts during palpation, peristalsis and the relief of the mucous membrane are preserved. Sometimes a bezoar simulates lymphosarcoma, gastric lymphoma.

Peptic ulcer of the stomach and duodenum is extremely common. 7-10% of the planet's population suffers. Annual exacerbations are observed in 80% of patients. In the light of modern concepts, this is a general chronic, cyclical, recurrent disease, which is based on complex etiological and pathological mechanisms of ulcer formation. This is the result of the interaction of aggression and defense factors (too strong aggression factors with weak defense factors). The aggression factor is peptic proteolysis during prolonged hyperchlorhydria. The protective factors include the mucous barrier, i.e. high regenerative ability of the mucosa, stable nervous trophism, good vascularization.

During the course of a peptic ulcer, three stages are distinguished: 1) functional disorders in the form of gastroduodenitis, 2) the stage of a formed ulcerative defect and 3) the stage of complications (penetration, perforation, bleeding, deformation, degeneration into cancer).

X-ray manifestations of gastroduodenitis: hypersecretion, impaired motility, restructuring of the mucosa in the form of coarse expanded cushion-shaped folds, rough microrelief, spasm or gaping of the transvaricus, duodenogastric reflux.

Signs of peptic ulcer disease are reduced to the presence of a direct sign (a niche on the contour or on the relief) and indirect signs. The latter, in turn, are divided into functional and morphological. Functional ones include hypersecretion, pyloric spasm, slower evacuation, local spasm in the form of a “pointing finger” on the opposite wall, local hypermatility, changes in peristalsis (deep, segmented), tone (hypertonicity), duodenogastric reflux, gastroesophageal reflux, etc. Morphological signs are filling defect due to the inflammatory shaft around the niche, convergence of folds (during scarring of the ulcer), cicatricial deformation (stomach in the form of a pouch, hourglass, snail, cascade, duodenal bulb in the form of a trefoil, etc.).

More often, the ulcer is localized in the area of ​​the lesser curvature of the stomach (36-68%) and proceeds relatively favorably. In the antrum, ulcers are also located relatively often (9-15%) and are found, as a rule, in young people, accompanied by signs of duodenal ulcer (late hunger pain, heartburn, vomiting, etc.). X-ray diagnosis is difficult due to pronounced motor activity, rapid passage of barium suspension, and difficulty in removing the ulcer to the contour. Often complicated by penetration, bleeding, perforation. In the cardiac and subcardial region, ulcers are localized in 2-18% of cases. Usually found in older people and present certain difficulties for endoscopic and radiological diagnosis.

The shape and size of the niches in peptic ulcer disease are variable. Often (13-15%) there is a multiplicity of lesions. The frequency of identifying a niche depends on many reasons (location, size, presence of fluid in the stomach, filling of the ulcer with mucus, blood clot, food debris) and ranges from 75 to 93%. Quite often there are giant niches (over 4 cm in diameter), penetrating ulcers (2-3 niches of complexity).

An ulcerative (benign) niche should be differentiated from a cancerous one. Cancer niches have a number of features:

1) the predominance of the longitudinal size over the transverse,

2) ulceration is located closer to the distal edge of the tumor,

3) the niche has an irregular shape with bumpy outlines, usually does not extend beyond the contour, the niche is painless on palpation, plus signs characteristic of a cancerous tumor.

Ulcer niches are usually

1) located near the lesser curvature of the stomach,

2) extend beyond the contours of the stomach,

3) have a cone shape,

4) the diameter is larger than the length,

5) painful on palpation, plus signs of peptic ulcer disease.

RADIATION STUDY OF THE MUSCULOSKETAL SYSTEM

In 1918, the world's first laboratory for studying the anatomy of humans and animals using x-rays was opened at the State X-ray Radiological Institute in Petrograd.

The X-ray method made it possible to obtain new data on the anatomy and physiology of the musculoskeletal system: to study the structure and function of bones and joints intravitally, in the whole organism, when a person is exposed to various environmental factors.

A group of domestic scientists made a great contribution to the development of osteopathology: S.A. Reinberg, D.G. Rokhlin, PA. Dyachenko and others.

The X-ray method is the leading one in the study of the musculoskeletal system. Its main techniques are: radiography (in 2 projections), tomography, fistulography, images with magnified X-ray images, contrast techniques.

An important method in the study of bones and joints is X-ray computed tomography. Magnetic resonance imaging should also be recognized as a valuable method, especially when examining bone marrow. To study metabolic processes in bones and joints, radionuclide diagnostic methods are widely used (bone metastases are detected before X-ray examination by 3-12 months). Sonography opens up new ways to diagnose diseases of the musculoskeletal system, especially in the diagnosis of foreign bodies that weakly absorb X-rays, articular cartilage, muscles, ligaments, tendons, accumulation of blood and pus in the periosseous tissues, periarticular cysts, etc.

Radiation research methods allow:

1. monitor the development and formation of the skeleton,

2. assess the morphology of the bone (shape, outline, internal structure, etc.),

3. recognize traumatic injuries and diagnose various diseases,

4. judge functional and pathological changes (vibration disease, marching foot, etc.),

5. study the physiological processes in bones and joints,

6. evaluate the response to various factors (toxic, mechanical, etc.).

Radiation anatomy.

Maximum structural strength with minimal waste of building material is characterized by the anatomical features of the structure of bones and joints (the femur can withstand a load along the longitudinal axis of 1.5 tons). Bone is a favorable object for x-ray examination, because contains many inorganic substances. Bone consists of bone beams and trabeculae. In the cortical layer they are closely adjacent, forming a uniform shadow, in the epiphyses and metaphyses they are located at some distance, forming a spongy substance, with bone marrow tissue between them. The relationship between the bone beams and the medullary spaces creates the bone structure. Hence, in the bone there are: 1) a dense compact layer, 2) a spongy substance (cellular structure), 3) a medullary canal in the center of the bone in the form of a lightening. There are tubular, short, flat and mixed bones. In each tubular bone, there are epiphysis, metaphysis and diaphysis, as well as apophyses. The epiphysis is an articular part of the bone covered with cartilage. In children it is separated from the metaphysis by the growth cartilage, in adults by the metaphyseal suture. Apophyses are additional points of ossification. These are the attachment points for muscles, ligaments and tendons. The division of bone into epiphysis, metaphysis and diaphysis is of great clinical importance, because some diseases have a favorite localization (osteomyelitis in the metadiaphysis, tuberculosis affects the pineal gland, Ewing's sarcoma is localized in the diaphysis, etc.). Between the connecting ends of the bones there is a light stripe, the so-called x-ray joint space, caused by cartilage tissue. Good photographs show the joint capsule, joint capsule, and tendon.

Development of the human skeleton.

In its development, the bone skeleton goes through membranous, cartilaginous and bone stages. During the first 4-5 weeks, the fetal skeleton is webbed and not visible on photographs. Developmental disorders during this period lead to changes that make up the group of fibrous dysplasias. At the beginning of the 2nd month of uterine life of the fetus, the membranous skeleton is replaced by cartilaginous skeleton, which is also not reflected on radiographs. Developmental disorders lead to cartilaginous dysplasia. Starting from the 2nd month and up to 25 years, the cartilaginous skeleton is replaced by bone. By the end of the prenatal period, most of the skeleton is osseous and the bones of the fetus are clearly visible on photographs of the pregnant abdomen.

The skeleton of newborns has the following features:

1. the bones are small,

2. they are structureless,

3. at the ends of most bones there are no ossification nuclei yet (the epiphyses are not visible),

4. X-ray joint spaces are large,

5. big brain skull and small facial,

6. relatively large orbits,

7. weakly expressed physiological curves of the spine.

The growth of the bone skeleton occurs due to the growth zones in length, in thickness - due to the periosteum and endosteum. At the age of 1-2 years, differentiation of the skeleton begins: ossification points appear, bones synostose, increase in size, and curvatures of the spine appear. The skeleton of the skeleton ends by the age of 20-25. Between 20-25 years and up to 40 years of age, the osteoarticular apparatus is relatively stable. From the age of 40, involutive changes begin (dystrophic changes in articular cartilage), thinning of the bone structure, the appearance of osteoporosis and calcification at the attachment points of ligaments, etc. The growth and development of the osteoarticular system is influenced by all organs and systems, especially the parathyroid glands, pituitary gland and central nervous system.

Plan for studying radiographs of the osteoarticular system. Need to evaluate:

1) shape, position, size of bones and joints,

2) state of the circuits,

3) the state of the bone structure,

4) identify the state of growth zones and ossification nuclei (in children),

5) study the condition of the articular ends of the bones (X-ray joint space),

6) assess the condition of soft tissues.

X-ray semiotics of bone and joint diseases.

The X-ray picture of bone changes in any pathological process consists of 3 components: 1) changes in shape and size, 2) changes in contours, 3) changes in structure. In most cases, the pathological process leads to bone deformation, consisting of lengthening, shortening and curvature, to a change in volume in the form of thickening due to periostitis (hyperostosis), thinning (atrophy) and swelling (cyst, tumor, etc.).

Changes in bone contours: Bone contours are normally characterized by evenness (smoothness) and clarity. Only in the places of attachment of muscles and tendons, in the area of ​​tubercles and tuberosities, the contours are rough. Lack of clarity of contours, their unevenness is often the result of inflammatory or tumor processes. For example, bone destruction as a result of the germination of cancer of the oral mucosa.

All physiological and pathological processes occurring in the bones are accompanied by changes in the bone structure, a decrease or increase in bone beams. A peculiar combination of these phenomena creates in the X-ray image such pictures that are inherent in certain diseases, allowing them to be diagnosed, the phase of development, and complications to be determined.

Structural changes in bone can be in the nature of physiological (functional) and pathological restructuring caused by various reasons (traumatic, inflammatory, tumor, degenerative-dystrophic, etc.).

There are over 100 diseases that are accompanied by changes in the mineral content of the bones. The most common is osteoporosis. This is a decrease in the number of bone beams per unit volume of bone. In this case, the overall volume and shape of the bone usually remain unchanged (if there is no atrophy).

There are: 1) idiopathic osteoporosis, which develops for no apparent reason and 2) with various diseases of internal organs, endocrine glands, as a result of taking medications, etc. In addition, osteoporosis can be caused by nutritional disorders, weightlessness, alcoholism, unfavorable working conditions, prolonged immobilization , exposure to ionizing radiation, etc.

Hence, depending on the causes, osteoporosis is distinguished as physiological (involutive), functional (from inactivity) and pathological (from various diseases). Based on prevalence, osteoporosis is divided into: 1) local, for example, in the area of ​​a jaw fracture after 5-7 days, 2) regional, in particular, involving the area of ​​the lower jaw branch with osteomyelitis 3) widespread, when the area of ​​the body and jaw branches is affected, and 4) systemic, accompanied by damage to the entire bone skeleton.

Depending on the X-ray picture, there are: 1) focal (spotty) and 2) diffuse (uniform) osteoporosis. Spotty osteoporosis is defined as foci of rarefaction of bone tissue ranging in size from 1 to 5 mm (reminiscent of moth-eaten matter). Occurs with osteomyelitis of the jaws in the acute phase of its development. Diffuse (glassy) osteoporosis is more often observed in the jaw bones. In this case, the bone becomes transparent, the structure is broadly looped, the cortical layer becomes thinner in the form of a very narrow dense line. It is observed in old age, with hyperparathyroid osteodystrophy and other systemic diseases.

Osteoporosis can develop within a few days and even hours (with causalgia), with immobilization - in 10-12 days, with tuberculosis it takes several months and even years. Osteoporosis is a reversible process. Once the cause is eliminated, the bone structure is restored.

Hypertrophic osteoporosis is also distinguished. At the same time, against the background of general transparency, individual bone beams appear hypertrophied.

Osteosclerosis is a symptom of bone diseases that are quite common. Accompanied by an increase in the number of bone beams per unit volume of bone and a decrease in interblock bone marrow spaces. At the same time, the bone becomes denser and structureless. The cortex expands, the medullary canal narrows.

There are: 1) physiological (functional) osteosclerosis, 2) idiopathic as a result of developmental anomalies (with marbled disease, myelorheostosis, osteopoikilia) and 3) pathological (post-traumatic, inflammatory, toxic, etc.).

Unlike osteoporosis, osteosclerosis requires quite a long time (months, years) to occur. The process is irreversible.

Destruction is the destruction of bone with its replacement by pathological tissue (granulation, tumor, pus, blood, etc.).

There are: 1) inflammatory destruction (osteomyelitis, tuberculosis, actinomycosis, syphilis), 2) tumor (osteogenic sarcoma, reticulosarcoma, metastases, etc.), 3) degenerative-dystrophic (hyperparathyroid osteodystrophy, osteoarthritis, cysts in deforming osteoarthritis, etc.) .

X-ray, regardless of the reasons, destruction is manifested by clearing. It can appear small or large focal, multifocal and extensive, superficial and central. Therefore, to establish the causes, a thorough analysis of the source of destruction is necessary. It is necessary to determine the location, size, number of lesions, the nature of the contours, the pattern and reaction of the surrounding tissues.

Osteolysis is the complete resorption of bone without its replacement by any pathological tissue. This is the result of deep neurotrophic processes in diseases of the central nervous system, damage to peripheral nerves (tabes dorsalis, syringomyelia, scleroderma, leprosy, lichen planus, etc.). The peripheral (end) parts of the bone (nail phalanges, articular ends of large and small joints) undergo resorption. This process is observed in scleroderma, diabetes mellitus, traumatic injuries, and rheumatoid arthritis.

Osteonecrosis and sequestration are a frequent accompaniment of bone and joint diseases. Osteonecrosis is the necrosis of a section of bone due to malnutrition. At the same time, the amount of liquid elements in the bone decreases (the bone “dries out”) and radiographically such an area is determined in the form of darkening (compaction). There are: 1) aseptic osteonekoosis (with osteochondropathy, thrombosis and embolism of blood vessels), 2) septic (infectious), occurring with osteomyelitis, tuberculosis, actinomycosis and other diseases.

The process of delimiting an area of ​​osteonecrosis is called sequestration, and the rejected area of ​​bone is called sequestration. There are cortical and spongy sequestra, regional, central and total. Sequestration is characteristic of osteomyelitis, tuberculosis, actinomycosis and other diseases.

Changes in bone contours are often associated with periosteal layers (periostitis and periostosis).

4) functional-adaptive periostitis. The last two forms should be called per gostoses.

When identifying periosteal changes, you should pay attention to their localization, extent and nature of the layers. Most often, periostitis is detected in the area of ​​the lower jaw.

According to their shape, linear, layered, fringed, spicule-shaped periostitis (periostosis) and periostitis in the form of a visor are distinguished.

Linear periostitis in the form of a thin strip parallel to the cortical layer of the bone usually occurs in inflammatory diseases, injuries, Ewing's sarcoma and characterizes the initial stages of the disease.

Layered (bulbous) periostitis is radiologically determined in the form of several linear shadows and usually indicates a jerky course of the process (Ewing's sarcoma, chronic osteomyelitis, etc.).

When linear layers are destroyed, fringed (broken) periostitis occurs. In its pattern it resembles pumice and is considered characteristic of syphilis. With tertiary syphilis, the following may be observed: and lace (comb-shaped) periostitis.

Spiculous (needle-shaped) periostitis is considered pathognomonic for malignant tumors. Occurs in osteogenic sarcoma as a result of tumor release into soft tissue.

Changes in X-ray joint space. which is a reflection of articular cartilage and can be in the form of narrowing due to the destruction of cartilage tissue (tuberculosis, purulent arthritis, osteoarthritis), expansion due to an increase in cartilage (osteochondropathia), as well as subluxation. When fluid accumulates in the joint cavity, the X-ray joint space does not widen.

Changes in soft tissues are very diverse and should also be the object of close X-ray examination (tumor, inflammatory, traumatic changes).

Damage to bones and joints.

Objectives of X-ray examination:

1. confirm the diagnosis or reject it,

2. determine the nature and type of fracture,

3. determine the number and degree of displacement of fragments,

4. detect dislocation or subluxation,

5. identify foreign bodies,

6. establish the correctness of medical manipulations,

7. exercise control during the healing process. Signs of a fracture:

1. fracture line (in the form of clearing and compaction) - transverse, longitudinal, oblique, intra-articular, etc. fractures.

2. displacement of fragments: widthwise or lateral, lengthwise or longitudinal (with entry, divergence, wedging of fragments), axially or angularly, along the periphery (spiral-shaped). The displacement is determined by the peripheral fragment.

Features of fractures in children are usually subperiosteal, in the form of a crack and epiphysiolysis. In elderly people, fractures are usually comminuted in nature, with intra-articular localization, with displacement of fragments; healing is slow, often complicated by the development of a pseudarthrosis.

Signs of vertebral body fractures: 1) wedge-shaped deformity with the tip directed anteriorly, compaction of the vertebral body structure, 2) the presence of a shadow of a hematoma around the affected vertebra, 3) posterior displacement of the vertebra.

There are traumatic and pathological fractures (as a result of destruction). Differential diagnosis is often difficult.

Monitoring fracture healing. During the first 7-10 days, the callus is of a connective tissue nature and is not visible on photographs. During this period, there is an expansion of the fracture line and rounding and smoothing of the ends of the broken bones. From 20-21 days, more often after 30-35 days, islands of calcification appear in the callus, clearly visible on radiographs. Complete calcification takes 8 to 24 weeks. Hence, radiographically it is possible to identify: 1) a slowdown in the formation of callus, 2) its excessive development, 3) Normally, the periosteum is not visible on the images. To identify it, compaction (calcification) and detachment are necessary. Periostitis is a response of the periosteum to one or another irritation. In children, radiological signs of periostitis are determined at 7-8 days, in adults - at 12-14 days.

Depending on the cause, they distinguish: 1) aseptic (in case of injury), 2) infectious (osteomyelitis, tuberculosis, syphilis), 3) irritative-toxic (tumors, suppurative processes) and emerging or formed false joint. In this case, there is no callus, the ends of the fragments are rounded and polished, and the medullary canal is closed.

Restructuring of bone tissue under the influence of excessive mechanical force. Bone is an extremely plastic organ that is rebuilt throughout life, adapting to living conditions. This is a physiological change. When the bone is presented with disproportionately increased demands, pathological restructuring develops. This is a breakdown of the adaptive process, disadaptation. Unlike a fracture, in this case there is repeated traumatization - the total effect of frequently repeated blows and shocks (the metal cannot withstand it either). Special zones of temporary disintegration arise - zones of restructuring (Loozerov zones), zones of enlightenment, which are little known to practical doctors and are often accompanied by diagnostic errors. The skeleton is most often affected lower limbs(foot, thigh, lower leg, pelvic bones).

The clinical picture distinguishes 4 periods:

1. within 3-5 weeks (after drill training, jumping, working with a jackhammer, etc.) pain, lameness, and pastiness appear over the site of reconstruction. There are no radiological changes during this period.

2. after 6-8 weeks, lameness, severe pain, swelling and local swelling increase. The images show a tender periosteal reaction (usually spindle-shaped).

3. 8-10 weeks. Severe lameness, pain, severe swelling. X-ray - pronounced periostosis of a spindle-shaped form, in the center of which there is a “fracture” line passing through the diameter of the bone and a poorly traced bone marrow canal.

4. recovery period. Lameness disappears, there is no swelling, radiographically the periosteal zone is reduced, the bone structure is restored. Treatment is first rest, then physiotherapy.

Differential diagnosis: osteogenic sacroma, osteomyelitis, osteodosteoma.

A typical example of pathological restructuring is marching foot (Deutschlander's disease, recruits' fracture, overloaded foot). The diaphysis of the 2nd-3rd metatarsal bone is usually affected. The clinic is described above. X-ray semiotics boils down to the appearance of a clearing line (fracture) and muff-like periostitis. The total duration of the disease is 3-4 months. Other types of pathological restructuring.

1. Multiple Loozer zones in the form of triangular notches along the anteromedial surfaces of the tibia (in schoolchildren during the holidays, athletes during excessive training).

2. Lacunar shadows located subperiosteally in the upper third of the tibia.

3. Bands of osteosclerosis.

4. In the form of an edge defect

Changes in bones during vibration occur under the influence of rhythmically operating pneumatic and vibrating tools (miners, miners, asphalt road repairmen, some branches of the metalworking industry, pianists, typists). The frequency and intensity of changes depends on the length of service (10-15 years). The risk group includes persons under 18 years of age and over 40 years of age. Diagnostic methods: rheovasography, thermography, cappilaroscopy, etc.

Basic radiological signs:

1. Islands of compaction (enostoses) can occur in all bones of the upper limb. The shape is irregular, the contours are uneven, the structure is uneven.

2. racemose formations are more often found in the bones of the hand (wrist) and look like a clearing 0.2-1.2 cm in size, round in shape with a rim of sclerosis around.

3. osteoporosis.

4. osteolysis of the terminal phalanges of the hand.

5. deforming osteoarthritis.

6. changes in soft tissues in the form of paraosseous calcifications and ossifications.

7. deforming spondylosis and osteochondrosis.

8. osteonecrosis (usually the lunate bone).

CONTRAST METHODS OF RESEARCH IN RADIATION DIAGNOSTICS

Obtaining an X-ray image is associated with uneven absorption of rays in the object. For the latter to receive an image, it must have a different structure. Hence, some objects, such as soft tissues and internal organs, are not visible on regular photographs and require the use of contrast media (CM) for their visualization.

Soon after the discovery of X-rays, ideas for obtaining images of various tissues using CS began to develop. One of the first CSs to achieve success were iodine compounds (1896). Subsequently, buroselectan (1930) for liver research, containing one iodine atom, found widespread use in clinical practice. Uroselektan was the prototype of all CS created later for the study of the urinary system. Soon, uroselectan (1931) appeared, which already contained two iodine molecules, which made it possible to improve image contrast while being well tolerated by the body. In 1953, a triiodinated urography drug appeared, which turned out to be useful for angiography.

In modern visualized diagnostics, CS provide a significant increase in the information content of x-ray examination methods, X-ray CT, MRI and ultrasound diagnostics. All CS have one purpose - to increase the difference between different structures in terms of their ability to absorb or reflect electromagnetic radiation or ultrasound. To fulfill their task, CS must reach a certain concentration in tissues and be harmless, which, unfortunately, is impossible, since they often lead to undesirable consequences. Hence, the search for highly effective and harmless CS continues. The urgency of the problem increases with the advent of new methods (CT, MRI, ultrasound).

Modern requirements for KS: 1) good (sufficient) image contrast, i.e. diagnostic effectiveness, 2) physiological validity (organ specificity, elimination along the route from the body), 3) general availability (cost-effectiveness), 4) harmlessness (absence of irritation, toxic damage and reactions), 5) ease of administration and speed of elimination from the body.

The routes of administration of the CS are extremely varied: through natural openings (lacrimal openings, external ear canal, through the mouth, etc.), through postoperative and pathological openings (fistula tracts, anastomosis, etc.), through the walls of the s/s and lymphatic system (puncture, catheterization, section, etc.), through the walls of pathological cavities (cysts, abscesses , caverns, etc.), through the walls of natural cavities, organs, ducts (puncture, trepanation), introduction into the cellular spaces (puncture).

Currently, all CS are divided into:

1. X-ray

2. MRI - contrast agents

3. Ultrasound - contrast agents

4. fluorescent (for mammography).

From a practical point of view, it is advisable to subdivide CS into: 1) traditional X-ray and CT contrast agents, as well as non-traditional ones, in particular, those created on the basis of barium sulfate.

Traditional X-ray contrast agents are divided into: a) negative (air, oxygen, carbon dioxide, etc.), b) positive, absorbing X-rays well. Contrast agents of this group attenuate radiation 50-1000 times compared to soft tissues. Positive CS, in turn, are divided into water-soluble (iodide preparations) and water-insoluble (barium sulfate).

Iodine contrast agents - their tolerance by patients is explained by two factors: 1) osmolarity and 2) chemotoxicity, including ionic exposure. To reduce osmolarity, it was proposed: a) the synthesis of ionic dimeric CS and b) the synthesis of nonionic monomers. For example, ionic dimeric CS were hyperosmolar (2000 m mol/l), while ionic dimers and nonionic monomers already had an osmolarity significantly lower (600-700 m mol/l), and their chemotoxicity also decreased. The nonionic monomer “Omnipak” began to be used in 1982 and its fate has been brilliant. Of the nonionic dimers, Vizipak is the next step in the development of ideal CS. It has isosmolarity, i.e. its osmolarity is equal to blood plasma (290 m mol/l). Nonionic dimers, more than any other CS at this stage of development of science and technology, correspond to the concept of “Ideal contrast agents.”

KS for RKT. In connection with the widespread use of RCT, selective contrast CS began to be developed for various organs and systems, in particular, the kidneys and liver, since modern water-soluble cholecystographic and urographic CS turned out to be insufficient. To a certain extent, Josefanat meets the requirements of the CS for RCT. This CS is selectively concentrated in functional hepatocytes and can be used for tumors and cirrhosis of the liver. Good reviews are also received when using Vizipak, as well as capsulated Iodixanol. All these CT scans are promising for visualizing liver megastases, liver carcinomas, and hemangiomas.

Both ionic and non-ionic (to a lesser extent) can cause reactions and complications. Side effects of iodine-containing CS are a serious problem. According to international statistics, kidney damage by the CS remains one of the main types of iatrogenic renal failure, accounting for about 12% of hospital-acquired acute renal failure. Vascular pain with intravenous administration of the drug, a feeling of heat in the mouth, a bitter taste, chills, redness, nausea, vomiting, abdominal pain, increased heart rate, a feeling of heaviness in the chest - this is not a complete list of the irritating effects of the CS. There may be cardiac and respiratory arrest, and in some cases death occurs. Hence, there are three degrees of severity of adverse reactions and complications:

1) mild reactions (“hot waves”, skin hyperemia, nausea, slight tachycardia). No drug therapy is required;

2) moderate degree (vomiting, rash, collapse). S/s and antiallergic drugs are prescribed;

3) severe reactions (anuria, transverse myelitis, respiratory and cardiac arrest). It is impossible to predict reactions in advance. All proposed prevention methods turned out to be ineffective. Recently, a test “at the tip of a needle” has been proposed. In some cases, premedication is recommended, in particular with prednisone and its derivatives.

Currently, the quality leaders among CS are “Omnipak” and “Ultravist”, which have high local tolerability, overall low toxicity, minimal hemodynamic effects and high image quality. Used for urography, angiography, myelography, gastrointestinal tract examination, etc.

X-ray contrast agents based on barium sulfate. The first reports on the use of an aqueous suspension of barium sulfate as a CS belong to R. Krause (1912). Barium sulfate absorbs X-rays well, mixes easily in various liquids, does not dissolve and does not form various compounds with the secretions of the digestive canal, is easily crushed and allows you to obtain a suspension of the required viscosity, and adheres well to the mucous membrane. For more than 80 years, the method of preparing an aqueous suspension of barium sulfate has been improved. Its main requirements boil down to maximum concentration, fineness and adhesiveness. In this regard, several methods have been proposed for preparing an aqueous suspension of barium sulfate:

1) Boiling (1 kg of barium is dried, sifted, 800 ml of water is added and boiled for 10-15 minutes. Then passed through cheesecloth. This suspension can be stored for 3-4 days);

2) To achieve high dispersion, concentration and viscosity, high-speed mixers are currently widely used;

3) Viscosity and contrast are greatly influenced by various stabilizing additives (gelatin, carboxymethylcellulose, flax seed mucilage, starch, etc.);

4) Use of ultrasonic installations. In this case, the suspension remains homogeneous and practically barium sulfate does not settle for a long time;

5) The use of patented domestic and foreign drugs with various stabilizing substances, astringents, and flavoring additives. Among them, barotrast, mixobar, sulfobar, etc. deserve attention.

The effectiveness of double contrast increases to 100% when using the following composition: barium sulfate - 650 g, sodium citrate - 3.5 g, sorbitol - 10.2 g, antifosmilan -1.2 g, water - 100 g.

A suspension of barium sulfate is harmless. However, if it gets into the abdominal cavity and respiratory tract, toxic reactions are possible, and with stenosis, the development of obstruction.

Non-traditional iodine-containing CSs include magnetic liquids - ferromagnetic suspensions that move in organs and tissues by an external magnetic field. Currently, there are a number of compositions based on ferrites of magnesium, barium, nickel, copper, suspended in a liquid aqueous carrier containing starch, polyvinyl alcohol and other substances with the addition of powdered metal oxides of barium, bismuth and other chemicals. Special devices with a magnetic device have been manufactured that are capable of controlling these CS.

It is believed that ferromagnetic preparations can be used in angiography, bronchography, salpingography, and gastrography. This method has not yet received widespread use in clinical practice.

Recently, among non-traditional contrast agents, biodegradable contrast agents deserve attention. These are drugs based on liposomes (egg lecithin, cholesterol, etc.), deposited selectively in various organs, in particular in the RES cells of the liver and spleen (iopamidol, metrizamide, etc.). Brominated liposomes for CT have been synthesized and excreted by the kidneys. CWs based on perfluorocarbons and other non-traditional chemical elements such as tantalum, tungsten, and molybdenum have been proposed. It is too early to talk about their practical application.

Thus, in modern clinical practice, mainly two classes of X-ray CS are used - iodinated and barium sulfate.

Paramagnetic CS for MRI. Magnevist is currently widely used as a paramagnetic contrast agent for MRI. The latter shortens the spin-lattice relaxation time of excited atomic nuclei, which increases the signal intensity and increases the tissue image contrast. After intravenous administration, it is rapidly distributed in the extracellular space. It is excreted from the body mainly by the kidneys using glomerular filtration.

Application area. The use of Magnevist is indicated in the study of central nervous system organs, in order to detect a tumor, as well as for differential diagnosis in cases of suspected brain tumor, acoustic neuroma, glioma, tumor metastases, etc. With the help of Magnevist, the degree of damage to the brain and spinal cord is reliably determined for multiple sclerosis and monitor the effectiveness of the treatment. Magnevist is used in the diagnosis and differential diagnosis of spinal cord tumors, as well as to identify the prevalence of tumors. “Magnevist” is also used for MRI of the whole body, including examination of the facial skull, neck area, chest and abdominal cavities, mammary glands, pelvic organs, and musculoskeletal system.

Fundamentally new CS have now been created and become available for ultrasound diagnostics. “Ekhovist” and “Levovost” deserve attention. They are a suspension of galactose microparticles containing air bubbles. These drugs make it possible, in particular, to diagnose diseases that are accompanied by hemodynamic changes in the right side of the heart.

Currently, thanks to the widespread use of radiopaque, paramagnetic agents and those used in ultrasound examinations, the possibilities for diagnosing diseases of various organs and systems have expanded significantly. Research continues to create new CS that are highly effective and safe.

FUNDAMENTALS OF MEDICAL RADIOLOGY

Today we are witnessing the ever-accelerating progress of medical radiology. Every year, new methods of obtaining images of internal organs and methods of radiation therapy are being introduced into clinical practice.

Medical radiology is one of the most important medical disciplines of the atomic age. It was born at the turn of the 19th and 20th centuries, when people learned that in addition to the familiar world we see, there is a world of extremely small quantities, fantastic speeds and unusual transformations. This is a relatively young science, the date of its birth is precisely indicated thanks to the discoveries of the German scientist W. Roentgen; (November 8, 1895) and the French scientist A. Becquerel (March 1996): discoveries of X-rays and the phenomena of artificial radioactivity. Becquerel's message determined the fate of P. Curie and M. Skladovskaya-Curie (they isolated radium, radon, and polonium). Rosenford's work was of exceptional importance for radiology. By bombarding nitrogen atoms with alpha particles, he obtained isotopes of oxygen atoms, i.e., the transformation of one chemical element into another was proven. This was the “alchemist” of the 20th century, the “crocodile”. He discovered the proton and neutron, which made it possible for our compatriot Ivanenko to create a theory of the structure of the atomic nucleus. In 1930, a cyclotron was built, which allowed I. Curie and F. Joliot-Curie (1934) to obtain a radioactive isotope of phosphorus for the first time. From that moment on, the rapid development of radiology began. Among domestic scientists, it is worth noting the studies of Tarkhanov, London, Kienbeck, Nemenov, who made a significant contribution to clinical radiology.

Medical radiology is a field of medicine that develops the theory and practice of using radiation for medical purposes. It includes two main medical disciplines: diagnostic radiation (diagnostic radiology) and radiation therapy (radiation therapy).

Radiation diagnostics is the science of using radiation to study the structure and functions of normal and pathologically altered human organs and systems for the purpose of preventing and recognizing diseases.

Radiation diagnostics includes x-ray diagnostics, radionuclide diagnostics, ultrasound diagnostics and magnetic resonance imaging. It also includes thermography, microwave thermometry, and magnetic resonance spectrometry. A very important direction in radiation diagnostics is interventional radiology: performing therapeutic interventions under the control of radiation studies.

Today no medical disciplines can do without radiology. Radiation methods are widely used in anatomy, physiology, biochemistry, etc.

Grouping of radiations used in radiology.

All radiation used in medical radiology is divided into two large groups: non-ionizing and ionizing. The former, unlike the latter, when interacting with the environment, do not cause ionization of atoms, i.e., their disintegration into oppositely charged particles - ions. To answer the question about the nature and basic properties of ionizing radiation, we should recall the structure of atoms, since ionizing radiation is intra-atomic (intranuclear) energy.

An atom consists of a nucleus and electron shells. Electron shells are a certain energy level created by electrons rotating around the nucleus. Almost all the energy of an atom lies in its nucleus - it determines the properties of the atom and its weight. The nucleus consists of nucleons - protons and neutrons. The number of protons in an atom is equal to the serial number of a chemical element on the periodic table. The sum of protons and neutrons determines the mass number. Chemical elements located at the beginning of the periodic table have an equal number of protons and neutrons in their nucleus. Such nuclei are stable. The elements at the end of the table have nuclei that are overloaded with neutrons. Such nuclei become unstable and decay over time. This phenomenon is called natural radioactivity. All chemical elements located in the periodic table, starting with No. 84 (polonium), are radioactive.

Radioactivity is understood as a phenomenon in nature when an atom of a chemical element decays, turning into an atom of another element with different chemical properties, and at the same time energy is released into the environment in the form of elementary particles and gamma rays.

There are colossal forces of mutual attraction between the nucleons in the nucleus. They are characterized by a large magnitude and act at a very short distance, equal to the diameter of the nucleus. These forces are called nuclear forces, which do not obey electrostatic laws. In cases where there is a predominance of some nucleons over others in the nucleus, nuclear forces become small, the nucleus is unstable, and decays over time.

All elementary particles and gamma quanta have charge, mass and energy. The unit of mass is taken to be the mass of a proton, and the unit of charge is the charge of an electron.

In turn, elementary particles are divided into charged and uncharged. The energy of elementary particles is expressed in ev, Kev, MeV.

To transform a stable chemical element into a radioactive one, it is necessary to change the proton-neutron equilibrium in the nucleus. To obtain artificially radioactive nucleons (isotopes), three possibilities are usually used:

1. Bombardment of stable isotopes with heavy particles in accelerators (linear accelerators, cyclotrons, synchrophasotrons, etc.).

2. Use of nuclear reactors. In this case, radionuclides are formed as intermediate products of the decay of U-235 (1-131, Cs-137, Sr-90, etc.).

3. Irradiation of stable elements with slow neutrons.

4. Recently, in clinical laboratories, generators have been used to obtain radionuclides (to obtain technetium - molybdenum, indium - charged with tin).

Several types of nuclear transformations are known. The most common are the following:

1. Decay reaction (the resulting substance shifts to the left at the bottom of the cell of the periodic table).

2. Electron decay (where does the electron come from, since it is not in the nucleus? It occurs when a neutron transforms into a proton).

3. Positron decay (in this case, a proton turns into a neutron).

4. Chain reaction - observed during the fission of uranium-235 or plutonium-239 nuclei in the presence of the so-called critical mass. The action of the atomic bomb is based on this principle.

5. Synthesis of light nuclei - thermonuclear reaction. The action of the hydrogen bomb is based on this principle. Fusion of nuclei requires a lot of energy; it is obtained from the explosion of an atomic bomb.

Radioactive substances, both natural and artificial, decay over time. This can be observed by the emanation of radium placed in a sealed glass tube. Gradually the glow of the tube decreases. The decay of radioactive substances follows a certain pattern. The law of radioactive decay states: “The number of decaying atoms of a radioactive substance per unit time is proportional to the number of all atoms,” that is, a certain part of the atoms always decays per unit time. This is the so-called decay constant (X). It characterizes the relative rate of decay. The absolute decay rate is the number of decays per second. The absolute decay rate characterizes the activity of a radioactive substance.

The unit of radionuclide activity in the SI system of units is the becquerel (Bq): 1 Bq = 1 nuclear transformation in 1 s. In practice, the extra-systemic unit curie (Ci) is also used: 1 Ci = 3.7 * 10 10 nuclear transformations in 1 s (37 billion decays). This is a lot of activity. In medical practice, milli and micro Ki are more often used.

To characterize the decay rate, the period during which the activity is halved (T = 1/2) is used. The half-life is determined in s, minutes, hours, years and millennia. The half-life, for example, of Ts-99t is 6 hours, and the half-life of Ra is 1590 years, and U-235 is 5 billion years. The half-life and decay constant are in a certain mathematical relationship: T = 0.693. Theoretically, complete decay of a radioactive substance does not occur, therefore, in practice, ten half-lives are used, i.e., after this period, the radioactive substance has almost completely decayed. The longest half-life of Bi-209 is 200 thousand billion years, the shortest is

To determine the activity of a radioactive substance, radiometers are used: laboratory, medical, radiographs, scanners, gamma cameras. All of them are built on the same principle and consist of a detector (receiving radiation), an electronic unit (computer) and a recording device that allows you to receive information in the form of curves, numbers or a picture.

Detectors are ionization chambers, gas-discharge and scintillation counters, semiconductor crystals or chemical systems.

The characteristic of its absorption in tissues is of decisive importance for assessing the possible biological effects of radiation. The amount of energy absorbed per unit mass of the irradiated substance is called dose, and the same amount per unit time is called radiation dose rate. The SI unit of absorbed dose is the gray (Gy): 1 Gy = 1 J/kg. The absorbed dose is determined by calculation, using tables, or by introducing miniature sensors into the irradiated tissues and body cavities.

A distinction is made between exposure dose and absorbed dose. Absorbed dose is the amount of radiation energy absorbed in a mass of matter. Exposure dose is the dose measured in air. The unit of exposure dose is the roentgen (milliroentgen, microroentgen). Roentgen (g) is the amount of radiant energy absorbed in 1 cm 3 of air under certain conditions (at 0 ° C and normal atmospheric pressure), forming an electric charge equal to 1 or forming 2.08x10 9 pairs of ions.

Dosimetry methods:

1. Biological (erythemal dose, epilation dose, etc.).

2. Chemical (methyl orange, diamond).

3. Photochemical.

4. Physical (ionization, scintillation, etc.).

According to their purpose, dosimeters are divided into the following types:

1. To measure radiation in a direct beam (condenser dosimeter).

2. Control and protection dosimeters (DKZ) - for measuring dose rates in the workplace.

3. Personal control dosimeters.

All these tasks are successfully combined in a thermoluminescent dosimeter (“Telda”). It can measure doses ranging from 10 billion to 10 5 rad, i.e. it can be used both for monitoring protection and for measuring individual doses, as well as doses during radiation therapy. In this case, the dosimeter detector can be mounted in a bracelet, ring, chest tag, etc.

RADIONUCLIDE RESEARCH PRINCIPLES, METHODS, CAPABILITIES

With the advent of artificial radionuclides, tempting prospects opened up for the doctor: by introducing radionuclides into the patient’s body, it is possible to monitor their location using radiometric instruments. In a relatively short period of time, radionuclide diagnostics has become an independent medical discipline.

The radionuclide method is a way to study the functional and morphological state of organs and systems using radionuclides and compounds labeled with them, which are called radiopharmaceuticals. These indicators are introduced into the body, and then using various instruments (radiometers) they determine the speed and nature of their movement and removal from organs and tissues. In addition, pieces of tissue, blood, and patient secretions can be used for radiometry. The method is highly sensitive and is carried out in vitro (radioimmunoassay).

Thus, the goal of radionuclide diagnostics is to recognize diseases of various organs and systems using radionuclides and compounds labeled with them. The essence of the method is registration and measurement of radiation from radiopharmaceuticals introduced into the body or radiometry of biological samples using radiometric instruments.

Radionuclides differ from their analogues - stable isotopes - only in their physical properties, that is, they are capable of decaying, producing radiation. The chemical properties are the same, so their introduction into the body does not affect the course of physiological processes.

Currently, 106 chemical elements are known. Of these, 81 have both stable and radioactive isotopes. For the remaining 25 elements, only radioactive isotopes are known. Today, the existence of about 1,700 nuclides has been proven. The number of isotopes of chemical elements ranges from 3 (hydrogen) to 29 (platinum). Of these, 271 nuclides are stable, the rest are radioactive. About 300 radionuclides find or may find practical application in various fields of human activity.

Using radionuclides, you can measure the radioactivity of the body and its parts, study the dynamics of radioactivity, the distribution of radioisotopes, and measure the radioactivity of biological media. Consequently, it is possible to study metabolic processes in the body, the functions of organs and systems, the course of secretory and excretory processes, study the topography of an organ, determine the speed of blood flow, gas exchange, etc.

Radionuclides are widely used not only in medicine, but also in a wide variety of fields of knowledge: archeology and paleontology, metallurgy, agriculture, veterinary medicine, forensic medicine. practice, criminology, etc.

The widespread use of radionuclide methods and their high information content have made radioactive studies an obligatory part of the clinical examination of patients, in particular the brain, kidneys, liver, thyroid gland and other organs.

History of development. As early as 1927, there were attempts to use radium to study the speed of blood flow. However, extensive study of the issue of using radionuclides in widespread practice began in the 40s, when artificial radioactive isotopes were obtained (1934 - Irene and F. Joliot Curie, Frank, Verkhovskaya). P-32 was first used to study metabolism in bone tissue. But until 1950, the introduction of radionuclide diagnostic methods into the clinic was hampered by technical reasons: there were not enough radionuclides, easy-to-use radiometric instruments, or effective research methods. After 1955, research in the field of visualization of internal organs continued intensively in terms of expanding the range of organotropic radiopharmaceuticals and technical re-equipment. The production of a colloidal solution of Au-198.1-131, P-32 was organized. Since 1961, the production of rose bengal-1-131 and hippuran-1-131 began. By 1970, certain traditions had generally developed in the use of specific research techniques (radiometry, radiography, gammatopography, clinical radiometry in vitro. The rapid development of two new techniques began: scintigraphy on cameras and radioimmunological studies in vitro, which today account for 80% of all radionuclide studies in clinic. Currently, the gamma camera can become as widespread as x-ray examination.

Today, a broad program has been outlined to introduce radionuclide research into the practice of medical institutions, which is being successfully implemented. More and more new laboratories are opening, new radiopharmaceuticals and methods are being introduced. Thus, literally in recent years, tumor-tropic (gallium citrate, labeled bleomycin) and osteotropic radiopharmaceuticals have been created and introduced into clinical practice.

Principles, methods, capabilities

The principles and essence of radionuclide diagnostics are the ability of radionuclides and compounds labeled with them to selectively accumulate in organs and tissues. All radionuclides and radiopharmaceuticals can be divided into 3 groups:

1. Organotropic: a) with directed organotropy (1-131 - thyroid gland, rose bengal-1-131 - liver, etc.); b) with an indirect focus, i.e. temporary concentration in an organ along the path of excretion from the body (urine, saliva, feces, etc.);

2. Tumorotropic: a) specific tumorotropic (gallium citrate, labeled bleomycin); b) nonspecific tumorotropic (1-131 in the study of metastases of thyroid cancer in the bones, rose bengal-1-131 in metastases to the liver, etc.);

3. Determination of tumor markers in blood serum in vitro (alphafetoprotein for liver cancer, carcinoembrysnal antigen - gastrointestinal tumors, choriogonadotropin - chorionepithelioma, etc.).

Advantages of radionuclide diagnostics:

1. Versatility. All organs and systems are subject to the radionuclide diagnostic method;

2. Complexity of research. An example is the study of the thyroid gland (determination of the intrathyroid stage of the iodine cycle, transport-organic, tissue, gammatoporgaphy);

3. Low radiotoxicity (radiation exposure does not exceed the dose received by the patient with one x-ray, and during radioimmunoassay, radiation exposure is completely eliminated, which allows the method to be widely used in pediatric practice;

4. High degree of accuracy of research and the possibility of quantitative recording of the obtained data using a computer.

From the point of view of clinical significance, radionuclide studies are conventionally divided into 4 groups:

1. Fully ensuring the diagnosis (diseases of the thyroid gland, pancreas, metastases of malignant tumors);

2. Determine dysfunction (kidneys, liver);

3. Establish the topographic and anatomical features of the organ (kidneys, liver, thyroid gland, etc.);

4. Obtain additional information in a comprehensive study (lungs, cardiovascular, lymphatic systems).

Requirements for radiopharmaceuticals:

1. Harmlessness (no radiotoxicity). Radiotoxicity should be negligible, which depends on the half-life and half-life (physical and biological half-life). The sum of the half-lives and half-lives is the effective half-life. The half-life should be from a few minutes to 30 days. In this regard, radionuclides are divided into: a) long-lived - tens of days (Se-75 - 121 days, Hg-203 - 47 days); b) medium-living - several days (1-131-8 days, Ga-67 - 3.3 days); c) short-lived - several hours (Ts-99t - 6 hours, In-113m - 1.5 hours); d) ultra-short-lived - several minutes (C-11, N-13, O-15 - from 2 to 15 minutes). The latter are used in positron emission tomography (PET).

2. Physiological validity (selectivity of accumulation). However, today, thanks to the achievements of physics, chemistry, biology and technology, it has become possible to include radionuclides in various chemical compounds, the biological properties of which differ sharply from the radionuclide. Thus, technetium can be used in the form of polyphosphate, macro- and microaggregates of albumin, etc.

3. The possibility of recording radiation from a radionuclide, i.e. the energy of gamma quanta and beta particles must be sufficient (from 30 to 140 KeV).

Methods of radionuclide research are divided into: a) research of a living person; b) examination of blood, secretions, excreta and other biological samples.

In vivo methods include:

1. Radiometry (of the whole body or part of it) - determination of the activity of a part of the body or organ. Activity is recorded as numbers. An example is the study of the thyroid gland and its activity.

2. Radiography (gammachronography) - on a radiograph or gamma camera, the dynamics of radioactivity is determined in the form of curves (hepatoradiography, radiorenography).

3. Gammatopography (on a scanner or gamma camera) - the distribution of activity in an organ, which allows one to judge the position, shape, size, and uniformity of drug accumulation.

4. Radioimmune anemia (radiocompetitive) - hormones, enzymes, drugs, etc. are determined in vitro. In this case, the radiopharmaceutical is introduced into a test tube, for example, with the patient’s blood plasma. The method is based on competition between a substance labeled with a radionuclide and its analogue in a test tube for complexing (combining) with a specific antibody. An antigen is a biochemical substance that needs to be determined (hormone, enzyme, drug). For analysis you must have: 1) the substance under study (hormone, enzyme); 2) its labeled analogue: the label is usually 1-125 with a half-life of 60 days or tritium with a half-life of 12 years; 3) a specific perceptive system, which is the subject of “competition” between the desired substance and its labeled analogue (antibody); 4) a separation system that separates bound radioactive substances from unbound ones (activated carbon, ion exchange resins, etc.).

Thus, radio competitive analysis consists of 4 main stages:

1. Mixing the sample, labeled antigen and specific receptor system (antibody).

2. Incubation, i.e., the antigen-antibody reaction to equilibrium at a temperature of 4 °C.

3. Separation of free and bound substances using activated carbon, ion exchange resins, etc.

4. Radiometry.

The results are compared with the reference curve (standard). The more of the starting substance (hormone, drug), the less of the labeled analogue will be captured by the binding system and the larger part of it will remain unbound.

Currently, over 400 compounds of various chemical natures have been developed. The method is an order of magnitude more sensitive than laboratory biochemical studies. Today, radioimmunoassay is widely used in endocrinology (diabetes mellitus diagnosis), oncology (search for cancer markers), in cardiology (myocardial infarction diagnosis), in pediatrics (child development disorders), in obstetrics and gynecology (infertility, fetal development disorders ), in allergology, toxicology, etc.

In industrialized countries, the main emphasis is now on organizing positron emission tomography (PET) centers in large cities, which, in addition to a positron emission tomograph, also includes a small-sized cyclotron for the on-site production of positron-emitting ultrashort-lived radionuclides. Where there are no small-sized cyclotrons, the isotope (F-18 with a half-life of about 2 hours) is obtained from their regional radionuclide production centers or generators (Rb-82, Ga-68, Cu-62) are used.

Currently, radionuclide research methods are also used for preventive purposes to identify hidden diseases. Thus, any headache requires a brain study with pertechnetate-Tc-99t. This type of screening allows us to exclude tumors and areas of hemorrhage. A reduced kidney detected in childhood by scintigraphy should be removed to prevent malignant hypertension. A drop of blood taken from the child's heel allows you to determine the amount of thyroid hormones. If there is a lack of hormones, replacement therapy is carried out, which allows the child to develop normally, keeping up with his peers.

Requirements for radionuclide laboratories:

One laboratory per 200-300 thousand population. It should preferably be placed in therapeutic clinics.

1. It is necessary to place the laboratory in a separate building, built according to a standard design with a security sanitary zone around it. It is forbidden to build children's institutions and catering units on the territory of the latter.

2. The radionuclide laboratory must have a certain set of premises (radiopharmaceutical storage, packaging, generator, washing, treatment room, sanitary inspection room).

3. Special ventilation is provided (five air changes when using radioactive gases), sewerage with a number of settling tanks in which waste of at least ten half-lives is kept.

4. Daily wet cleaning of the premises must be carried out.

Rice. 6.6. Polymerase chain reaction.

polar biological research methods. They are DNA hybridization, isothermal amplification, system of isothermal amplification of target sequences, ligase chain reaction, polymerase chain reaction (PCR). The most widely used is PCR with an MBT-specific primer. The reaction is based on the amplification of a specific

DNA section of M. tuberculosis (Fig. 6.6). PCR is a highly sensitive and rapid method for laboratory diagnosis of tuberculosis. Identification of MBT in diagnostic material if there are 1 - 10 cells in the sample, it can be carried out in 5-6 hours. To carry out PCR, special test systems and laboratories are required.

6.5. Radiation diagnostic methods

In phthisiology, X-ray and ultrasonic methods, radionuclide scanning, and magnetic resonance imaging are used. Positron emission tomography (PET) may also be important in differential diagnosis.

X-ray methods. For mass examinations of the population and primary diagnosis of diseases of the lungs and mediastinum, they are widely used. fluorography. Another name for this method is photoradiography, since the image from the X-ray screen is photographed on film (film fluorography). The format of a standard modern frame is 100 x 100 mm.

Compared to conventional radiography, fluorography can significantly increase the throughput of an X-ray machine, reduce the cost of film and its processing, and facilitate archive storage. Resolution of lung fluorogram High Quality almost the same as an x-ray, therefore in some cases a fluorogram with a frame format of 100 x 100 mm replaces a survey x-ray of the lungs. Among the negative aspects of film fluorography, the main one is the high radiation exposure to the patient and staff.

Film is now being replaced by digital (digital) X-ray fluorography, which has many significant

benefits. The main ones are high quality, informativeness and the possibility of computer image processing. Radiation exposure to the subject under study digital fluorography 10-15 times lower than with film (in direct projection, 0.05 and 0.7 mSv, respectively). It is also necessary to note the high speed of image acquisition, the possibility of combined viewing and printing of several images on paper, their transmission over a distance, the convenience of storing and subsequently retrieving all data, and the low cost of the study.

Currently, digital X-ray fluorography is becoming widespread for control examinations of large populations for the purpose of timely detection of tuberculosis, cancer and other diseases of the breast organs. It also successfully replaces plain chest radiography as a diagnostic method. Russian industry produces different models of digital scanning and pulse devices (Fig. 6.7).

X-ray of the lungs start with a survey image in the anterior direct projection (a cassette with film at the anterior chest wall). In case of pathological changes in the posterior sections of the lungs, it is advisable to take a survey image in the posterior direct projection (a cassette with film at the posterior chest wall). Then they take overview pictures in a lateral projection - right and left. In a right lateral photograph, the right lateral surface of the chest is adjacent to the box with the film; in a left one, the left one is adjacent. Radiographs in lateral projections are necessary to determine the localization of the pathological process in the lobes and segments of the lungs, to identify changes in the interlobar fissures and in the lungs behind the shadows of the heart and diaphragm. In case of bilateral pulmonary pathology, it is better to take photographs in oblique projections, which produce separate images of the right and left lungs.

X-rays are usually taken at inspiratory height. Under exhalation conditions, images are taken to better identify the edge of a collapsed lung and pleural adhesions in the presence of pneumothorax, as well as to determine the displacement of mediastinal organs in pathology of the lungs and pleura.

The information content of X-ray images can be increased by changing the exposure or hardness of the X-ray beams. Such pictures are called overexposed and hard. They are produced by patients exudative pleurisy and with massive pleural overlays, after surgical operations on the lungs, for better identification of the walls of the trachea and bronchi. In overexposed and hard photographs, various structures can be revealed in areas of intense darkness that are not visible in a normal photograph. However, low-intensity shadows are not displayed in such images.

Rice. 6.7. Digital fluorographs made in Russia.

Survey radiographs in frontal and lateral projections, if necessary, are supplemented with targeted images with a narrow beam of rays. To do this, under the control of X-ray television, the patient is placed in a position that allows the lung field under study to be freed from interfering bone and other formations.

It should be noted that the radiological signs of some diseases are often so prominent that one experienced glance at the radiograph is enough to make a diagnosis.

Fluoroscopy is performed, as a rule, using electron-optical intensification of X-ray images and X-ray television. This method is used after radiography for certain indications. These include monitoring during targeted photographs and diagnostic punctures, X-ray bronchological, angiographic and fistulographic studies. Fluoroscopy is necessary to identify freely moving fluid in the pleural cavity, determine the mobility of the diaphragm and the condition of the pleural sinuses. In many cases, fluoroscopic control is better than radiography in the first days after intrathoracic surgical operations. Finally, fluoroscopy is used to assess the mobility of the diaphragm and perform tests with an increase and decrease in intrathoracic pressure (Valsalva and Müller maneuvers, Holtzknecht-Jacobson sign). Documentation of the results of these tests can be done by video recording and X-ray filming.

Computed tomography (CT) - a method of x-ray examination that has received universal recognition and is used in all areas of clinical medicine. CT provides an image of the transverse layers of the human body (axial projection). The X-ray tube rotates around the longitudinal axis of the patient's body. A thin beam of rays passes at different angles through the layer under study and is captured by numerous scintillation detectors that move along with the tube. Different densities of tissues through which X-rays pass cause different changes in the intensity of their beam. It is recorded with high accuracy by detectors, processed by a computer, and transformed into an image of the cross-section under study on a television screen. Thus, a CT scan is not a picture in the usual sense of the word, but a drawing made by a computer based on a mathematical analysis of the degree of absorption of X-rays by tissues of various densities (computational tomography).

CT scanners with conventional scanning technology involve step-by-step movement of the table with the patient and stopping the X-ray tube after each rotation cycle. They make it possible to study transverse layers with a thickness of 2 to 10 mm. Scanning one layer lasts several seconds. A significant increase in contrast can be obtained by intravenous administration of a radiopaque solution. Axial (transverse) images can be reconstructed using a computer into frontal, lateral and oblique tomograms of the examined area. The brightness and contrast of the image can be changed to a large extent.

within our limits. When performing a CT scan of the respiratory organs, 6-12 standard sections are performed. All results, in parallel with the image on the television screen, are stored in the computer memory and can be reproduced in the form of a drawing on Polaroid photographic paper or X-ray film.

A significant capability of CT is the quantitative assessment of the density of the tissues and media being studied in arbitrary units according to the Honesfield scale. The density of water on this scale is 0, air (-) 1000 units, light (+) 600 units, bone (+) 1000 units.

In recent years, spiral and multiplanar CT have become recognized methods for improving visualization in the study of the lungs. Spiral CT technology involves simultaneous constant rotation of the X-ray tube with longitudinal movement of the patient. In this regard, instead of imaging individual slices, data is collected from the entire volume of the area under study. During a full revolution of the X-ray tube, depending on the pitch of the spiral, a different number of cuts can be made.

The advantages of the above scanning methods are a significant reduction in time (from 10 to 20 s) and the possibility of research with one breath hold. The resolution increases, the quality of the image of moving organs improves, and favorable conditions are created for the study of children and seriously ill patients. Spiral CT has opened the way for reconstruction and creation of high-quality volumetric images. It is possible to obtain pictures similar to bronchoscopic (computer bronchoscopy), bronchographic (computer bronchography), and with intravenous contrast, angiographic (computer angiography). The radiation exposure is reduced, since there is less need for repeated sections to clarify diagnostic questions. With multiplanar tomography, by increasing the number of detectors, resolution is further improved by reducing scanning time, reducing artifacts, and expanding image processing capabilities. In general, improved radiation imaging methods for various intrathoracic pathologies make it possible to obtain a three-dimensional image and more accurately assess the anatomical situation, including the presence, localization and extent of pathological changes over time. CT also allows for high accuracy of transthoracic fecal biopsy and complex pleural punctures.

Using CT with special image processing, it is possible to obtain virtual bronchoscopic picture

Magnetic resonance imaging (MRI). The many advantages of MRI are the basis for its use in

Rice. 6.8. Fragment of a virtual bronchoscopic picture. CT scan of the chest.

examination of the brain and spinal cord, bones and joints, large vessels of the chest cavity, heart and other internal organs. One of the important advantages of the method is the absence of radiation exposure to the patient and medical personnel.

The patient is placed on the tomograph table. The area of ​​the body being examined is placed in a strong magnetic field. It turns protons in its direction and creates a magnetic moment in the tissues, oriented parallel to the external magnetic field.

liu. When exposed to pulses that are directed perpendicular to the magnetic field from the radio transmitting coil, the total magnetic vector changes direction and begins to rotate around a new axis. The result is the induction of an electric current in the receiving coil - the appearance of a magnetic resonance signal. It is converted by a special analyzer and transmitted to the screen of a black and white monitor.

The nature of the MRI image is mainly determined by the so-called relaxation time, proton density and the researcher’s tasks. In this case, T-1 relaxation is understood as the time during which the initial orientation of protons is restored in accordance with the external magnetic field. Relaxation T-2 is the time of weakening of the field created by the radio frequency pulse. Changing the time between radiofrequency pulses makes it possible to obtain images of different contrasts and to differentiate well various fabrics. It is also possible to obtain images in different planes and perform three-dimensional reconstruction.

Interpretation of MRI images is more complex than the X-ray images that are familiar to the vast majority of doctors. For example, air, bone, and fibrous tissue have a long T-1 time, a short T-2 time, and appear dark on images.

MRI is contraindicated if the patient has a pacemaker or other metal implant. The study can be quite lengthy and therefore difficult to perform in children and seriously ill patients.

Angiopulmonography is to contrast and

X-ray examination of the pulmonary artery and its branches. There are two main methods of angiopulmonography - general and selective.

During general angiopulmonography, a contrast solution is injected through a catheter into a vein in the arm, the superior vena cava, or into the cavity of the right heart. X-ray images are produced serially on a special angiographic machine. This method requires a significant amount of contrast agent (50-60 ml) and usually does not provide a clear image of the pulmonary vessels, especially with pathological changes in the lungs. Amputation of blood vessels does not always reflect their true condition.

Selective pulmonary angiography is technically somewhat more complicated, but is used more often. It is carried out after catheterization of the corresponding branch of the pulmonary artery. Serial photographs are taken after the injection of 10-12 ml of contrast solution. Typically, selective pulmonary angiography is combined with recording pressure in the pulmonary circulation and studying blood gases.

Indications for angiopulmonography are limited. It is used to diagnose thrombosis and pulmonary embolism, as well as to determine the ability to expand a long-term collapsed lung - the state of the vessels is used to determine the degree of pneumofibrosis.

Technical capabilities make it possible to perform general angiopulmonography in a digital version with introduction into

vein with a small amount of contrast solution. At the same time, computer processing of video signals allows you to obtain high-quality images.

Bronchial arteriography consists of catheterization, contrast and radiography of the bronchial arteries and their branches. The study is carried out under local anesthesia and X-ray television control. A special needle with a mandrel is used to puncture the femoral artery below the inguinal fold. The mandrin is replaced with a metal conductor, through which a radiopaque catheter with a curved end is inserted into the lumen of the artery. The guidewire is then removed and the catheter is advanced into the aorta. Using the tip of the catheter, the mouths of the bronchial arteries are successively found and a catheter is inserted into them, and then a contrast agent (hypaque, urografin, urotrast or their analogues) at a speed of 35 ml/s in an amount of 5-12 ml. Serial radiography is performed.

The main indication for bronchial arteriography is pulmonary hemorrhage unknown etiology and localization. In such cases, arteriograms may reveal dilatation and pathological tortuosity bronchial arteries, release of contrast agent beyond their limits (extravasation), focal or diffuse hypervascularization, aneurysm

we of the bronchial arteries, their thrombosis, retrograde filling of the peripheral branches of the pulmonary artery through arterioarterial anastomoses.

Contraindications to the study: severe atherosclerosis, patient obesity, pulmonary heart failure.

A complication of bronchial arteriography can be a hematoma in the area of ​​femoral artery puncture. A rare but serious complication is vascular damage to the spinal cord with dysfunction of the lower extremities and pelvic organs. Prevention of complications is ensured by strict adherence to methodological and technical principles and details of the study.

Bronchography. Contrast X-ray examination of the bronchi is carried out under local anesthesia in the form of positional (non-directional) or selective (directional) bronchography. During positional bronchography, a catheter is inserted into the trachea through the nose, and the patient's body is placed in an optimal position during the administration of a contrast agent. Selective bronchography is based on catheterization of the bronchus being examined. To carry it out, catheters of various designs and techniques are used.

Previously, bronchography was used very widely. Currently, due to the widespread use of CT, this method has lost its former significance.

Pleurography allows you to contrast and clarify the boundaries purulent cavity in patients with pleural empyema. First, a pleural puncture is performed and the pleural contents are aspirated. Then, under X-ray television control, 30-40 ml of a warm radiopaque solution (propyliodone, urografin) is injected into the pleural cavity. We take x-rays in different projections, changing the position of the patient. After completion of the study, the contrast agent with the remaining pleural contents is aspirated. The information that is obtained with pleurography can in most cases be obtained using CT.

Fistulography is used to examine patients with various thoracic and thoracobronchial fistulas. Before fistulography, it is advisable to determine the direction of the fistulous tract by probing. The contrast agent is injected into the fistula tract with a syringe through a catheter under X-ray television control. Oil or water soluble radiocontrast agents are used. Then radiography is performed in different projections, changing the position of the patient, or CT. During the study and after analyzing the images, the anatomical features of the fistula are revealed, its connection with the pleural cavity and the bronchial tree is established. If the contrast agent penetrates

Rice. 6.9. Radionuclide study of blood flow in the lungs.

paratha into the bronchial tree, retrograde fistulobronchography is obtained. After

At the end of the study, the drug is aspirated through the catheter if possible, and the patient is asked to cough well.

Ultrasound methods, in

In particular, ultrasound scanning is distinguished by its safety, the ability to conduct multiple studies, and high resolution.

In phthisiatric practice, ultrasound methods

useful for accurately determining and monitoring the size of peripheral lymph nodes(cervical, axillary, inguinal). Using ultrasound, it is possible to determine the presence of fluid in the pleural cavity, since if it is present, a hypoechoic zone is noted between the parietal pleura and the lung. Ultrasonic testing allows you to select a point for puncture of the pleural cavity. After pneumonectomy, dynamic determination of the fluid level in the pleural cavity can often replace X-ray examination.

Ultrasound diagnostics is important and often decisive when examining men and women with suspected tuberculosis of the genitourinary system. It is also necessary to monitor the dynamics of the process when treating phthisiourological and phthisiogynecological patients.

Radionuclide (radioisotopic) methods are of key importance for regional assessment of ventilation and blood flow in the lungs. They are based on inhalation or, more often, intravenous administration of radiopharmaceuticals labeled gamma emitting radionuclides. This xenon-air mixture (133 Xe), albumin macroaggregate ( l31 I or 99m Tc), indium citrate ( 133m In), albumin microspheres ( 99m Тс or l33m In), etc. The distribution of the administered drug is registered using scintillation gamma cameras with a computer (Fig. 6.9). In this case, both static and dynamic scintigraphy is possible in anterior, posterior and lateral projections. All parameters are usually determined as percentages according to the division of the pulmonary fields into upper, middle and lower zones. However, mathematical modeling makes it possible to assess ventilation and blood flow in the lungs