X-rays in the spectrum of electromagnetic waves occupy a place between ultraviolet and gamma radiation. They have a high penetrating ability, passing through the thickness of the substance almost in a straight line, without experiencing refraction at the interfaces between the media. Therefore, a point source of X-ray radiation creates a shadow image of the entire structure of the object under study on the screen or on X-ray film.

X-ray radiation is generated by an X-ray machine using X-ray tubes - electric vacuum devices in which an electron beam is accelerated in an electric field with a strength of tens to hundreds of kilovolts, focused on a massive anode and decelerated on its surface. At the same time, more than 90% of the electron energy is converted into heat and heats the anode, and a smaller part is converted into radiation. X-ray machines are divided into two groups by their design: stationary - high-performance, used in the study of objects in the X-ray rooms (laboratories), and portable, allowing to conduct research outside the walls of the laboratory, for example, in a museum exposition.

The domestic industry does not produce X-ray machines intended for the study of works of art. Therefore, museums and restoration workshops use either medical diagnostic devices or industrial control devices. The characteristics of these devices must meet the following requirements: the voltage of the x-ray tube of devices designed for x-rays of oil and tempera painting should vary smoothly in the range from 10 to 50 kV, and for devices designed for special studies of painting, for example, photoelectronography, within from 100 to 300 kV. (1 The focus diameter of the x-ray tube should not exceed 1-2 mm. The devices should be as small as possible and have a relatively high productivity of several shots per hour.

Laboratory equipment for X-ray studies. The X-ray room of a restoration organization or a museum, equipped with one apparatus, must consist of at least three rooms - an equipment room equipped with biological protection, exhaust ventilation and grounding; control room, from which the X-ray machine is controlled during shooting; and a photographic laboratory in which the processed x-ray film is processed.

An X-ray machine and a number of devices necessary for filming are installed in the control room. X-ray studies of works of art are very specific. Therefore, X-ray machines, in order to use them for the indicated purposes, must be subjected to some alteration. First of all, it is necessary to install the emitter of the X-ray machine in special racks at the floor level. Then the office is equipped with a special filming table with a size of at least 1.5x1.5m. The design of the table should ensure the stable position of the picture during the shooting. The height of the table is determined by the focal length of the apparatus. To irradiate an area of ​​30x40 cm (X-ray film size), the height of the table, depending on the angle of exit of the X-rays, ranges from 0.7 to 1.5 m. for the passage of the X-ray beam with a size slightly larger than the size of the X-ray film. For the correct guidance of the X-ray beam on the studied area of ​​painting, the table is equipped with a centering device, the most simple option which is the application of marks that determine the position of the opening in relation to the outlet of the tube.

The analysis of the obtained radiographs is carried out on a specially made negatoscope, which differs from the medical large size, allowing you to simultaneously consider several images.

The captured radiographs must be recorded in the journal, after which they are given a registration number and placed in special cabinets. To avoid distortion, radiographs are stored in boxes or folders in an upright position.

X-ray painting. When X-raying, the picture is placed on the shooting table with the paint layer up so that the fragment under study is above the opening through which the X-ray radiation passes. An X-ray film is placed on top of the picture in a light-protective bag of black paper, lightly pressing the bag with a sheet of felt or rubber of the appropriate size.

During radiography, a stream of x-rays falls on the work under study, losing its intensity when passing through the picture, depending on the material and thickness of the corresponding area of ​​the painting. The transmitted radiation, falling on the X-ray film, illuminates it according to the intensity of the radiation incident on it. Thus, a shadow image of the object under study is formed on the x-ray film.

The main parameter that determines the quality of an x-ray image is the value of the anode voltage of the tube. Depending on the type of tube and the scheme of the rectifier device of the X-ray machine, the optimal values ​​of this voltage during the study various kinds paintings may change, which requires trial shooting.

The exposure time is determined by the dose of radiation incident on the film and depends on several factors (anode voltage, tube current, focal length), which are determined individually for each specific installation.

When shooting a work, it is necessary to take into account the design features of the base so that its image does not distort the x-ray image of the paint layer. For example, when X-raying a painting on a canvas stretched on a stretcher with a cross, you should place the painting with the paint layer down when shooting, and place the bag with the film between the canvas and the cross.

X-ray photography of paintings in the exhibition halls of museums and in other rooms not equipped for this purpose requires additional devices. When shooting, it is recommended to use lightweight collapsible stands that ensure the correct position of the work. The upper edges of the posts should be covered with a soft material. It is necessary to make special holders or tripods to fix the emitter of the device.

Characterization of x-ray films. X-ray films are used for photographic fixation of x-ray images. Usually they are made double-sided, with a high content of silver bromide in the emulsion layer, due to which their greater sensitivity is achieved.

The main characteristics of X-ray films, in addition to sensitivity, include contrast, ranging from 2 to 4.5, and resolution, which determines the size of the details detected during the study. The resolution depends on the grain size of the silver bromide and is expressed as the number of distinct line pairs per millimeter of emulsion surface. For different films, this value is not the same.

The exposed film, as already mentioned, is subjected to photo processing. The recommended developer composition, development time, and fixing solution composition are included in the instructions for each grade of film. The complexity of processing the film lies in its relatively large size - 30x40 cm, so it is carried out in special tanks, where it is mounted on metal frames.

Special types of radiographic studies. X-ray study of painting allows you to identify the features of the structure and structure of the work. However, in some cases, depending on the nature of a particular thing or the task at hand, it is necessary to use special types of radiography. Mastery of these techniques allows you to obtain important information using the same equipment as with conventional radiography.

Obtaining enlarged images, or microroentgenography, greatly expands the possibilities of radiographic examination. There are three ways to obtain enlarged x-ray images.

The first is that a countertype (negative obtained by the contact method) is made from the area of ​​interest of a conventional radiograph, from which an enlarged photographic image is obtained when printed.

The second method is that the x-ray film is exposed at some distance from the work under study. Depending on the ratio of the distances from the emitter to the product and from the emitter to the film, it is possible to obtain a different degree of magnification of the image on the radiograph. The exposure time in this case increases in proportion to the square of the distance from the emitter to the film. To obtain radiographs of high magnification and high quality, it is necessary to use devices with sharp focus tubes.

The third method is a combination of the two considered: a countertype is made from an enlarged radiograph, which is enlarged during projection printing.

Obtaining information about the three-dimensional structure of the work can be obtained by the methods of angular and stereoroentgenography. The first method is that radiography is carried out with a beam of x-rays directed not perpendicular to the surface of the work, but at a certain angle. At the same time, in a number of cases, it is possible to get rid of the screening effect of the elements of the base structure, and to judge the depth of their location by the shift of the shadow image of individual hidden elements of the work relative to the usual radiograph.

However, the most complete information about the volumetric structure of the work can be obtained by the method of stereoroentgenography, which consists in obtaining an X-ray stereo pair when shooting the work at a certain angle from two positions of the emitter located on the sides of the central axis of the radiographed area. The study of a stereo pair is carried out on a stereo negatoscope or a stereo comparator, which makes it possible to determine the relative location of individual, rather large elements of the work.

The acquisition of separated x-ray images by the method of layer-by-layer contact radiography provides important information in the study of double-sided painting. The essence of the method lies in the fact that during the shooting, the x-ray film is in contact with the surface of the work under study, and the x-ray tube or the work under study move relative to each other. In this case, it is possible to obtain a satisfactory image of the paint layer, in contact with which the x-ray film was located; the image of the opposite side is smeared (Fig. 64).

64. Our Lady of Kanev. Double-sided remote icon of the 16th century. with the image of the Savior on the back. Ordinary photographs of the sides and their layer-by-layer contact radiographs.

The use of portable X-ray machines makes it possible to apply a simplified method of layer-by-layer contact radiography, when shooting on a film, contact pressed against the surface under study, is performed sequentially from several points. With this method, the quality of radiographs is somewhat reduced, but no additional devices are required, which makes it possible to obtain separated images from large works directly in the premises of museums (Fig. 65).

Fig. 65. Summary radiograph of a fragment of the double-sided icon "George" (Fig. 21) with the image of the Mother of God on the back and layer-by-layer contact radiograph taken from the side of the image of George.

The special methods of X-ray studies include the method of compensatography, which allows obtaining X-ray images of parquet paintings without the interfering influence of the base fastening elements. The method consists in the fact that the gaps between the parquet are filled with a material whose X-ray absorption coefficient coincides with the absorption coefficient of the parquet wood. As such, it is recommended to use ethacryl plastic granules.

In cases where the work of easel painting is made on a metal base, when examining fragments of monumental painting, paintings transferred to another base using a thick layer of lead white or written on a thick layer of lead white primer, direct X-ray photography is impossible. In all these cases, good results for studying the paint layer are obtained by using the photoelectronography method (2. The essence of the method lies in the fact that an image is recorded on a photographic film that is formed not directly by X-rays, but by electrons emitted from the surface of the paint layer under the action of X-rays. Emitter An X-ray apparatus operating at an anode voltage of about 120-300 kV irradiates the area under study, while soft (long-wave) X-ray radiation is absorbed by a metal (for example, copper) filter with a thickness of 0.5 to 2 mm, and under the action of a hard (short-wave) X-ray radiation, the irradiated atoms of the substance under study begin to emit photoelectrons, causing blackening of the emulsion layer of the photographic film, contact pressed to the front side of the painting.As a result, an image is created corresponding to the distribution of pigments, which include metals, intensely emitting rolling electrons (Fig. 66).

66. Shota Rustaveli. Medieval Georgian miniature on paper. An ordinary photograph and a photoelectron diffraction pattern, which made it possible to reveal the details of the image.

Since the photographic film is also partially illuminated by X-rays passing through the photographic emulsion, the optimal exposure time, which depends on many factors (anode voltage, radiation intensity, filter thickness and material, film sensitivity and the distance between the emitter and the surface under study), is determined by the time at which the veil of the emulsion from X-rays is negligible. For the study of painting, it is recommended to use photographic films of low sensitivity and high resolution. Ensuring light insulation of the film and tight contact between it and the studied area of ​​painting is achieved by using special cassettes.

Interpretation of the radiographic image. An x-ray photograph, which is a cut-off picture of the structure of the object under study, combines in one plane the image of the basis of the work, the ground and the paint layer. In order to correctly interpret an X-ray image, it is necessary to have knowledge physical characteristics materials of painting, to understand the technique of painting, to imagine the processes of aging and destruction of the work in time and the changes that could be made to it in the process of restoration work.

In addition to the registration journal, where the number of each image is entered, it is advisable in the X-ray laboratory to have special cards for the X-ray study of works. (3

Such cards usually record the inventory number of the work in the museum's collection, the name of the painting, its author, the time of creation, the size of the work, as well as the characteristics of the base material, soil, and technique of execution. On the same card, a photograph of the work is pasted or attached to it in the form in which it was received for research; on the photo indicate the areas of radiography. A separate column is assigned to describe the results of an X-ray examination of the base, soil, pattern and paint layer. The card is signed by the employee who performed the radiography and analysis of the radiograph, and the corresponding dates. Based on this map, a conclusion is made on the x-ray examination of the work.

The analysis of the X-ray image is possible only when it is directly compared with the work. Interpretation begins with an analysis of the features of the basis of the work, which, as a rule, is well read on the x-ray, regardless of whether the picture is painted on wood or on canvas, and then proceeds to the next structural elements of the picture - the ground, the drawing and the paint layer.

The purpose of the radiographic study of the paint layer is to study the peculiarities of painting techniques, identify the underlying images, determine the areas of destruction and the nature of the restoration intervention.

The nature of the resulting image of the paint layer depends on the system of its construction, the composition of pigments and soil, and the base material. The protective coating of the picture practically does not weaken the x-ray radiation, so its image is absent on the x-ray. Starting to interpret the radiographic image of the paint layer, it is necessary first of all to note the nature of its transmission on the radiograph. There are the following main gradations: the details of the paint layer are well revealed in highlights and shadows, well revealed in highlights and poorly in shadows, poorly revealed in highlights and not revealed in shadows, not revealed at all.

When attributing paintings, an important role is played by a comparative analysis of radiographs, based on the repetition of techniques in the works of one artist. Conducting a comparative analysis of radiographs of the studied work with radiographs of the artist's original paintings, it is first necessary to identify areas of the author's painting. Then the state of its preservation is determined and, as a result of this study, the possibility of a comparison. Comparative analysis involves the study of all the structural elements of the compared paintings and aims to establish their identity. At the same time, a comparative analysis of only two radiographs (the original and the work under study) cannot always provide sufficient material for a conclusion.

Radiation safety measures. X-ray radiation is one of the types of ionizing radiation, which in large doses can cause irreversible changes in the human body. Therefore, the safety requirements for radiographic studies are quite strict. They are defined by a number of documents, the implementation of which is mandatory, and violation leads to strict liability. (4 Verification of compliance with radiation safety standards and permission to operate X-ray laboratories is given by the sanitary and epidemiological station of the district or city in which the restoration workshop or museum is located.

X-ray laboratory personnel must undergo special training and have a medical permit to work with ionizing radiation. When X-rays are taken, at least two specialists must be present in the control room. Entry of unauthorized persons into the laboratory during the operation of the X-ray unit is strictly prohibited.

1) Conventional radiography is not applicable to the study of wall paintings, however, sometimes it can be used to study its fragments, especially to determine the design of their mount; the voltage range of apparatus intended for such research should be from 60 to 120 kV.

2) In the literature, this method is often also called autoradiography, emissionography or electron diffraction.

3) If an organization conducting radiography conducts a comprehensive study of painting, then the results of an x-ray examination can be recorded in a single map summarizing such a study.

4) See: Radiation safety standards. NRB-69. M., 1971; Basic sanitary rules for working with radioactive substances and other types of ionizing radiation. OSGG-72. M., 1973; Instructions for commissioning and operation of x-ray laboratories at museums. Approved by the Ministry of Culture of the USSR on July 26, 1966.

Radiology as a science dates back to November 8, 1895, when the German physicist Professor Wilhelm Conrad Roentgen discovered rays, later named after him. Roentgen himself called them X-rays. This name has been preserved in his homeland and in Western countries.

Basic properties of X-rays:

X-rays, proceeding from the focus of the X-ray tube, propagate in a straight line.

They do not deviate in an electromagnetic field.

Their propagation speed is equal to the speed of light.

X-rays are invisible, but when absorbed by certain substances, they cause them to glow. This glow is called fluorescence and is the basis of fluoroscopy.

X-rays have a photochemical effect. This property of X-rays is the basis of radiography (the currently generally accepted method for producing X-ray images).

X-ray radiation has an ionizing effect and gives the air the ability to conduct electricity. Neither visible, nor thermal, nor radio waves can cause this phenomenon. Based on this property, X-rays, like the radiation of radioactive substances, are called ionizing radiation.

An important property of X-rays is their penetrating power, i.e. the ability to pass through the body and objects. The penetrating power of X-rays depends on:

1. From the quality of the rays. The shorter the length of the X-rays (i.e., the harder the X-rays), the deeper these rays penetrate and, conversely, the longer the wavelength of the rays (the softer the radiation), the shallower they penetrate.

   From the volume of the body under study: the thicker the object, the more difficult it is for X-rays to “penetrate” it. The penetrating power of X-rays depends on the chemical composition and structure of the body under study. The more atoms of elements with high atomic weight and serial number (according to the periodic table) in a substance exposed to X-rays, the stronger it absorbs X-rays and, conversely, the lower the atomic weight, the more transparent the substance for these rays. The explanation for this phenomenon is that electromagnetic radiation with a very short wavelength, which are X-rays, a lot of energy is concentrated.

X-rays have an active biological effect. In this case, DNA and cell membranes are critical structures.

One more circumstance must be taken into account. X-rays obey the inverse square law, i.e. The intensity of X-rays is inversely proportional to the square of the distance.

Gamma rays have the same properties, but these types of radiation differ in the way they are produced: X-rays are obtained in high-voltage electrical installations, and gamma radiation is due to the decay of atomic nuclei.

Methods of X-ray examination are divided into basic and special, private. The main methods of x-ray examination include: radiography, fluoroscopy, electroroentgenography, computed x-ray tomography.

X-ray - transillumination of organs and systems using x-rays. X-ray is an anatomical and functional method that provides an opportunity to study normal and pathological processes and conditions of the body as a whole, individual organs and systems, as well as tissues by the shadow pattern of a fluorescent screen.

Advantages:

Allows you to examine patients in various projections and positions, due to which you can choose a position in which pathological shadow formation is better detected.

The possibility of studying the functional state of a number of internal organs: lungs, at various phases of respiration; pulsation of the heart with large vessels.

Close contact between the radiologist and the patients, which makes it possible to supplement the X-ray examination with the clinical one (palpation under visual control, targeted history), etc.

Disadvantages: relatively large radiation exposure to the patient and attendants; low throughput for working time doctor; limited capabilities of the researcher's eye in detecting small shadow formations and fine tissue structures, etc. Indications for fluoroscopy are limited.

Electron-optical amplification (EOA). The operation of an electron-optical converter (IOC) is based on the principle of converting an X-ray image into an electronic image with its subsequent transformation into an amplified light image. The brightness of the screen glow is enhanced up to 7 thousand times. The use of an EOS makes it possible to distinguish details with a size of 0.5 mm, i.e. 5 times smaller than with conventional fluoroscopic examination. When using this method, X-ray cinematography can be used, i.e. recording an image on film or videotape.

Radiography is photography using x-rays. When taking X-rays, the object to be photographed must be in close contact with the cassette loaded with film. X-ray radiation coming out of the tube is directed perpendicularly to the center of the film through the middle of the object (the distance between the focus and the patient's skin under normal operating conditions is 60-100 cm). Indispensable equipment for radiography are cassettes with intensifying screens, screening grids and a special x-ray film. The cassettes are made of opaque material and correspond in size to the standard sizes of produced X-ray film (13 × 18 cm, 18 × 24 cm, 24 × 30 cm, 30 × 40 cm, etc.).

Intensifying screens are designed to increase the light effect of x-rays on photographic film. They represent cardboard, which is impregnated with a special phosphor (calcium tungsten acid), which has a fluorescent property under the influence of X-rays. Currently, screens with phosphors activated by rare earth elements are widely used: lanthanum oxide bromide and gadolinium oxide sulfite. The very good efficiency of the rare earth phosphor contributes to the high light sensitivity of the screens and ensures high image quality. There are also special screens - Gradual, which can even out the existing differences in the thickness and (or) density of the subject. The use of intensifying screens significantly reduces the exposure time for radiography.

Special movable gratings are used to filter out the soft rays of the primary flux that can reach the film, as well as the secondary radiation. Processing of the filmed films is carried out in a photo laboratory. The processing process is reduced to development, rinsing in water, fixing and thorough washing of the film in flowing water, followed by drying. Drying of films is carried out in drying cabinets, which takes at least 15 minutes. or occurs naturally, with the picture being ready the next day. When using processing machines, images are obtained immediately after the study. Advantage of radiography: eliminates the disadvantages of fluoroscopy. Disadvantage: the study is static, there is no possibility of assessing the movement of objects during the study.

Electroroentgenography. Method for obtaining x-ray images on semiconductor wafers. The principle of the method: when rays hit a highly sensitive selenium plate, the electric potential changes in it. The selenium plate is sprinkled with graphite powder. Negatively charged powder particles are attracted to those areas of the selenium layer in which positive charges have been preserved, and are not retained in those areas that have lost their charge under the action of X-rays. Electroradiography allows you to transfer the image from the plate to paper in 2-3 minutes. More than 1000 shots can be taken on one plate. The advantage of electroradiography:

Rapidity.

Profitability.

Disadvantage: insufficiently high resolution in the study of internal organs, a higher dose of radiation than with radiography. The method is used mainly in the study of bones and joints in trauma centers. Recently, the use of this method has been increasingly limited.

Computed X-ray tomography (CT). The creation of X-ray computed tomography was the most important event in radiation diagnostics. Evidence of this is the award of the Nobel Prize in 1979 to the famous scientists Cormac (USA) and Hounsfield (England) for the creation and clinical testing of CT.

CT allows you to study the position, shape, size and structure of various organs, as well as their relationship with other organs and tissues. Various models of mathematical reconstruction of X-ray images of objects served as the basis for the development and creation of CT. Advances achieved with the help of CT in the diagnosis of various diseases served as a stimulus for the rapid technical improvement of devices and a significant increase in their models. If the first generation of CT had one detector, and the time for scanning was 5-10 minutes, then on tomograms of the third - fourth generations, with 512 to 1100 detectors and high-capacity computers, the time to obtain one slice decreased to milliseconds, which practically allows you to explore all organs and tissues, including the heart and blood vessels. Currently, spiral CT is used, which makes it possible to carry out a longitudinal reconstruction of the image, to study rapidly occurring processes (contractile function of the heart).

CT is based on the principle of creating an X-ray image of organs and tissues using a computer. CT is based on the registration of X-ray radiation by sensitive dosimetric detectors. The principle of the method lies in the fact that after the rays pass through the patient's body, they do not fall on the screen, but on the detectors, in which electrical impulses arise, transmitted after amplification to the computer, where, according to a special algorithm, they are reconstructed and create an image of the object that is fed from the computer on a TV monitor. The image of organs and tissues on CT, unlike traditional x-rays, is obtained in the form of transverse sections (axial scans). With helical CT, a three-dimensional image reconstruction (3D mode) with high spatial resolution is possible. Modern installations make it possible to obtain sections with a thickness of 2 to 8 mm. The X-ray tube and radiation receiver move around the patient's body. CT has a number of advantages over conventional X-ray examination:

First of all, high sensitivity, which makes it possible to differentiate individual organs and tissues from each other in terms of density up to 0.5%; on conventional radiographs, this figure is 10-20%.

CT makes it possible to obtain an image of organs and pathological foci only in the plane of the examined section, which gives a clear image without layering of formations lying above and below.

CT makes it possible to obtain accurate quantitative information about the size and density of individual organs, tissues and pathological formations.

CT makes it possible to judge not only the state of the organ under study, but also the relationship of the pathological process with surrounding organs and tissues, for example, tumor invasion into neighboring organs, the presence of other pathological changes.

CT allows you to get topograms, i.e. a longitudinal image of the area under study, like an x-ray, by moving the patient along a fixed tube. Topograms are used to establish the extent of the pathological focus and determine the number of sections.

CT is indispensable for radiotherapy planning (radiation mapping and dose calculation).

CT data can be used for diagnostic puncture, which can be successfully used not only to detect pathological changes, but also to assess the effectiveness of treatment and, in particular, antitumor therapy, as well as to determine relapses and associated complications.

Diagnosis by CT is based on direct radiographic features, i.e. determining the exact localization, shape, size of individual organs and the pathological focus and, most importantly, on indicators of density or absorption. The absorbance index is based on the degree to which an X-ray beam is absorbed or attenuated as it passes through the human body. Each tissue, depending on the density of the atomic mass, absorbs radiation differently, therefore, at present, the absorption coefficient (HU) on the Hounsfield scale has been developed for each tissue and organ. According to this scale, HU water is taken as 0; bones with the highest density - for +1000, air with the lowest density - for -1000.

The minimum size of a tumor or other pathological focus, determined by CT, ranges from 0.5 to 1 cm, provided that the HU of the affected tissue differs from that of healthy tissue by 10-15 units.

In both CT and X-ray examinations, it becomes necessary to use the “image enhancement” technique to increase the resolution. Contrast in CT is performed with water-soluble radiopaque agents.

The “enhancement” technique is carried out by perfusion or infusion administration of a contrast agent.

Such methods of X-ray examination are called special. The organs and tissues of the human body become visible if they absorb x-rays to varying degrees. Under physiological conditions, such differentiation is possible only in the presence of natural contrast, which is determined by the difference in density ( chemical composition of these organs), size, position. The bone structure is well detected against the background of soft tissues, the heart and large vessels against the background of airy lung tissue, however, the chambers of the heart under conditions of natural contrast cannot be distinguished separately, as well as the organs of the abdominal cavity, for example. The need to study organs and systems with the same density by X-rays led to the creation of a technique for artificial contrasting. The essence of this technique is the introduction of artificial contrast agents into the organ under study, i.e. substances having a density different from the density of the organ and its environment.

Radiocontrast agents (RCS) are usually divided into substances with high atomic weight (X-ray positive contrast agents) and low (X-ray negative contrast agents). The contrast agents must be harmless.

Contrast agents that absorb intensely x-rays (positive radiopaque agents) are:

Suspensions of salts of heavy metals - barium sulfate, used to study the gastrointestinal tract (it is not absorbed and excreted through natural routes).

Aqueous solutions of organic compounds of iodine - urographin, verografin, bilignost, angiographin, etc., which are introduced into the vascular bed, enter all organs with the blood flow and give, in addition to contrasting the vascular bed, contrasting other systems - urinary, gallbladder, etc. .

Oily solutions of organic iodine compounds - yodolipol, etc., which are injected into fistulas and lymphatic vessels.

Non-ionic water-soluble iodine-containing radiopaque agents: ultravist, omnipak, imagopak, vizipak are characterized by the absence of ionic groups in the chemical structure, low osmolarity, which significantly reduces the possibility of pathophysiological reactions, and thereby causes a low number of side effects. Non-ionic iodine-containing radiopaque agents cause a lower number of side effects than ionic high-osmolar contrast media.

X-ray negative or negative contrast agents - air, gases "do not absorb" x-rays and therefore shade well the organs and tissues under study, which have a high density.

Artificial contrasting according to the method of administration of contrast agents is divided into:

The introduction of contrast agents into the cavity of the organs under study (the largest group). This includes studies of the gastrointestinal tract, bronchography, fistula studies, all types of angiography.

The introduction of contrast agents around the studied organs - retropneumoperitoneum, pneumothorax, pneumomediastinography.

The introduction of contrast agents into the cavity and around the studied organs. This includes parietography. Parietography in diseases of the gastrointestinal tract consists in obtaining images of the wall of the investigated hollow organ after the introduction of gas, first around the organ, and then into the cavity of this organ. Usually, parietography of the esophagus, stomach and colon is performed.

A method based on the specific ability of some organs to concentrate individual contrast agents and at the same time shade it against the background of surrounding tissues. These include excretory urography, cholecystography.

Side effects of RCS. Body reactions to the introduction of RCS are observed in approximately 10% of cases. By nature and severity, they are divided into 3 groups:

Complications associated with the manifestation of a toxic effect on various organs with functional and morphological lesions of them.

The neurovascular reaction is accompanied by subjective sensations (nausea, feeling of heat, general weakness). Objective symptoms in this case are vomiting, lowering blood pressure.

Individual intolerance to RCS with characteristic symptoms:

1. From the side of the central nervous system- headaches, dizziness, agitation, anxiety, fear, the occurrence of convulsive seizures, cerebral edema.

   Skin reactions - hives, eczema, itching, etc.

   Symptoms associated with impaired activity of the cardiovascular system - pallor of the skin, discomfort in the region of the heart, drop in blood pressure, paroxysmal tachycardia or bradycardia, collapse.

   Symptoms associated with respiratory failure - tachypnea, dyspnea, asthma attack, laryngeal edema, pulmonary edema.

RCS intolerance reactions are sometimes irreversible and fatal.

The mechanisms of development of systemic reactions in all cases are similar in nature and are due to the activation of the complement system under the influence of RCS, the effect of RCS on the blood coagulation system, the release of histamine and other biologically active substances, a true immune response, or a combination of these processes.

In mild cases of adverse reactions, it is enough to stop the injection of RCS and all phenomena, as a rule, disappear without therapy.

In case of severe complications, it is necessary to immediately call the resuscitation team, and before it arrives, introduce 0.5 ml of adrenaline, intravenously 30-60 mg of prednisolone or hydrocortisone, 1-2 ml of an antihistamine solution (diphenhydramine, suprastin, pipolfen, claritin, hismanal), intravenously 10 % calcium chloride. In case of laryngeal edema, tracheal intubation should be performed, and if it is impossible, tracheostomy should be performed. In case of cardiac arrest, immediately begin artificial respiration and chest compressions without waiting for the arrival of the resuscitation team.

Premedication with antihistamine and glucocorticoid drugs is used to prevent the side effects of RCS on the eve of the X-ray contrast study, and one of the tests is also performed to predict the patient's hypersensitivity to RCS. The most optimal tests are: determination of histamine release from peripheral blood basophils when mixed with RCS; the content of total complement in the blood serum of patients assigned for X-ray contrast examination; selection of patients for premedication by determining the levels of serum immunoglobulins.

Among the rarer complications, there may be "water" poisoning during barium enema in children with megacolon and gas (or fat) vascular embolism.

A sign of "water" poisoning, when a large amount of water is quickly absorbed through the walls of the intestine into the bloodstream and an imbalance of electrolytes and plasma proteins occurs, there may be tachycardia, cyanosis, vomiting, respiratory failure with cardiac arrest; death may occur. First aid in this case is intravenous administration of whole blood or plasma. Prevention of complications is to carry out irrigoscopy in children with a suspension of barium in an isotonic saline solution, instead of an aqueous suspension.

Signs of vascular embolism are: the appearance of a feeling of tightness in the chest, shortness of breath, cyanosis, slowing of the pulse and a drop in blood pressure, convulsions, cessation of breathing. In this case, you should immediately stop the introduction of the RCS, put the patient in the Trendelenburg position, start artificial respiration and chest compressions, inject 0.1% - 0.5 ml of adrenaline solution intravenously and call the resuscitation team for possible tracheal intubation, implementation of artificial respiration and carrying out further therapeutic measures.

Radiography, as one of the cheapest and simplest non-invasive diagnostic methods, is used almost everywhere in modern medicine. An x-ray medical imaging method is a technique by which tissues and organs can be imaged. This is a kind of photographing opaque "objects", or rather their internal structure.

An X-ray examination is prescribed both for diagnosis and for monitoring the dynamics of the quality of treatment. In order for the method to give the most accurate results, it is important to follow certain rules, a kind of technical conditions.

X-ray for an adult

Radiography allows you to determine the position of certain organs, their tone, shape, peristalsis, etc. Both children and adults, regardless of gender, can prescribe such a diagnosis.

• Radiography of the spine may be needed if a tumor is suspected, with inflammatory and infectious diseases, as well as degenerative-dystrophic disorders, including osteochondrosis.
• Chest X-ray is almost indispensable in the diagnosis of the heart, lungs and airways. Using this method, it is possible to detect various neoplasms, deformations of organs and tissues, inflammatory processes, for example, to detect foreign objects in the respiratory tract.
• X-ray of the stomach and duodenum can be prescribed for tumor processes, suspected ulcers, or, for example, gastritis.
• Bone x-ray can help detect neoplastic, infectious, and traumatic changes.
• X-ray of the nose, or rather the paranasal sinuses, can be prescribed to determine the tumor, to detect the inflammatory process, etc.
• An x-ray of the colon will help identify diverticula, obstructions, polyps, etc.

Today, there are many radiation diagnostic methods, and the task of a medical specialist is to select only those options that will be the most informative, painless and minimal in terms of finances. The X-ray method is an excellent way to obtain data on the structure and functions of various organs and systems.

Radiography for a child can be carried out with various devices, specialized and universal equipment is distinguished. Universal devices are most often installed in clinics and sanatoriums. Specialized units are designed for one type of research in a narrow field of medicine. It can be dentistry, mammology, etc.

In pediatric practice, the field of application of radiography is extensive, including urology, orthopedics, and abdominal surgery.

Digital radiography

For the first time, radiography (as a method of medical imaging) was invented back in 1895. This diagnostic method immediately became popular in all developed countries of the world, and already in 1986 the first pictures were taken in Russia.

In 1918, the first hospital was opened, where radiography was the main manipulation. The method has been improved every year and today radiography is considered the most basic way to study the human musculoskeletal system. It is also worth noting lung diagnostics, where radiography is a screening imaging technique.

The modern world of innovations uses the X-ray machine not only in medical practice, but also in forensics and technology. After all, computer diagnostics have replaced classical radiography. Digital radiography has a lot of advantages, it allows you to make more accurate and clear images of tissues and organs, it is convenient to work with it in terms of speed. It is also important to highlight the fact that X-ray results no longer need to be stored on film, which patients lose in most cases. Computer diagnostic results are stored electronically and can be easily moved from the database of one clinic to another.

Digital radiography can be carried out using portable or stationary equipment. The diagnostic unit operates at high speed and can produce up to 200 images in 60 minutes. The equipment consists of a computer, keyboard, display, which are connected to the scanner. And that, in turn, is most often located inside the x-ray machine. Diagnostic beams pass through the organs and tissues of the patient and fall on the plate. Which is instantly scanned. The resulting image is transferred to a computer, thanks to which the diagnostician can study it in detail, print it on a printer, transfer it via e-mail or, for example, save to a separate disk or memory card. Thus, it is always possible to make a backup copy of the snapshot.

There are also disadvantages in digital radiography. For health, strong X-ray exposure is not desirable. However, the clarity of the picture may deteriorate. To obtain a high quality image, it is desirable to increase the radiation doses. This is the main drawback of this diagnostic.

The informative value of such diagnostics in traumatic brain injuries is negligible. But the method, of course, plays a role in the examination of patients with pituitary neoplasms, skull fractures. The method is often prescribed after birth injuries. With the help of radiography, congenital malformations can be determined.

Carry out diagnostics under the supervision of a specialist. The procedure does not require any specific preparatory manipulations (food restrictions are not needed). During irradiation, it is desirable for the patient to free his head from metal products, you need to remove jewelry, glasses.

When x-raying the skull, the patient is seated in a comfortable chair or laid on a couch. During the diagnosis, it is not advisable for him to move. To prevent the patient from moving his head during X-ray exposure, specialists prefer to use assistive devices and objects. These can be textile bags filled with sand, bandages for fixation, foam pads, etc. Most often, x-rays of the skull are performed in five projections.

With the aforementioned skull diagnosis, the radiologist immediately after the procedure develops the film and checks the results. The specialist will without fail pay attention to the thickness, size and shape of the bones of the skull, evaluate the vascular pattern and cranial sutures. In such a study of the results, age norms will be taken into account.

X-ray of the nose: paranasal sinuses

The paranasal sinuses are located inside the upper jaw. They are air cavities lined with mucous membranes.

The bone walls of the sinuses of the nose can be deformed due to the inflammatory process, mechanical injuries. Changes in the mucous membranes can also be observed, but the sinus cavities are often filled with fluid or dense masses. X-ray of the paranasal sinuses allows you to determine pathological changes in one or both sinuses, to refute or confirm the diagnosis associated with a tumor process or tissue inflammation. Also, such diagnostics helps to identify the exact localization of benign and malignant tumors.

Nasal x-rays are prescribed for acute and chronic sinusitis, mucocele, fractures of the structures that form the paranasal sinuses, etc.

Normally, the paranasal sinuses appear black on x-rays and are radiolucent. Deviations from the norm can be different:

• foreign bodies;
• liquid;
• linear bone defects;
• loss of transparency, dark spots;
• thickening of the bone walls;
• destruction of the walls;
• a formation that bulges into the sinus cavity, etc.

As for precautionary measures, radiography of the nose and other organs is not prescribed during the period of gestation. Before the procedure, it is desirable to remove all metal jewelry.

X-ray beams easily penetrate the lung tissue. Any formations, foreign bodies, infiltrates, liquids look like dark areas on the diagnostic results.

Chest X-ray allows you to quickly and accurately detect:

• lung diseases that are accompanied by inflammatory processes, such as pneumonia, pleurisy, etc.;
• diseases of the heart and mediastinum, or rather heart failure and tumors;
• foreign bodies, their shape, size, localization (in the gastrointestinal tract or respiratory tract).

Also, chest x-ray allows you to evaluate the work of the lungs, determine the location of the drainage in the pleural cavity, the catheter in the pulmonary artery, etc.

Radiography of the stomach and small intestine

Diagnosis of the small intestine and stomach using radiography can be prescribed by the attending physician to assess their condition. Carry out the procedure with contrast.

The patient takes orally a barium suspension that passes through the gastrointestinal tract. It is at the moment of movement of barium that the diagnostician observes the peristalsis of the gastrointestinal tract. To fix data on any violations, targeted x-rays are performed.

• persistent heartburn and/or diarrhea,
• swallowing problems.
• vomiting with an admixture of blood.
• sudden weight loss.

X-ray examination can identify dysmotility gastrointestinal tract, esophagus, hernia, etc. The procedure is contraindicated in pregnancy, intestinal perforation and obstruction.

It is important to know that barium can cause constipation, so your doctor may recommend laxatives. After the diagnostic procedure, the feces will be discolored, possibly even 2-3 days. Any worrisome symptoms, including pain, bloating, constipation, should be reported to your doctor as soon as possible.

X-rays are also used to examine the duodenum. Relaxation duodenography involves the introduction (through a catheter) of air and a special solution of barium sulfate. A procedure is prescribed when signs of disturbances in the work of the pancreas and directly in the duodenum are detected.

Diagnosis of this kind is not prescribed for pregnant women, as well as patients with glaucoma and severe diseases of the cardiovascular system. Contraindications apply to patients with type 1 diabetes mellitus (prescribe with caution).

Oral cholecystography

X-ray examination is performed using a contrast agent.

Oral cholecystography is prescribed for symptoms that indicate a violation of the patency of the bile ducts. It can be pain in the right hypochondrium, yellowness of the skin, intolerance to fats. The study is prescribed to confirm or refute the preliminary diagnosis associated with gallbladder diseases. With the help of oral cholecystography, stones, tumors and various inflammatory changes can be detected.

This diagnostic method is not very common and doctors increasingly prefer ultrasound and computed tomography. In diseases with a severe clinical picture and pregnancy, oral cholecystography is not prescribed.

Percutaneous transhepatic cholangiography

X-ray diagnosis of the biliary tract using an iodine-containing contrast solution is called percutaneous transhepatic cholangiography. Thanks to such a study, it is possible to establish the cause of pain in the right hypochondrium, determine obstructive jaundice, clarify the level and causes of obstruction in the bile ducts.

The attending physician will tell you about the preparation for the procedure, aftercare and precautions. It is worth noting that this diagnostic method do not carry out in patients who are allergic to iodine, pregnant women and people with cholangitis (inflammation in the intra- and extrahepatic biliary tract).

X-ray diagnosis of pathologies of the biliary tract and pancreatic ducts is carried out using a contrast agent, which is injected through the nipple. Doctors recommend such a study for suspected various diseases of the pancreas, as well as for jaundice, the cause of which has not been determined.

With the help of endoscopic retrograde cholangiopancreatography, stones or tumors in the pancreatic ducts and bile ducts can be detected. Such diagnostics are not prescribed during the period of gestation, as well as for infectious lesions, diseases of the lungs and heart. Endoscopic retrograde cholangiopancreatography is not used for obstruction of the duodenum and esophagus.

Angiography of the celiac trunk and mesenteric arteries

Examination of the vessels of the abdominal cavity using radiography involves the use of a contrast agent administered intra-arterially. Thanks to a special diagnostic technique, the doctor can visualize the abdominal vasculature. Step-by-step X-ray images are a great opportunity to study the bloodstream of blood vessels. This method research is indispensable in cases where it is impossible to establish the source of GI bleeding using an endoscope. Also, angiography can be recommended for tumor formations, when ultrasound diagnostics and CT did not give accurate results.

Angiography can also be prescribed for cirrhosis of the liver, and also as a diagnosis, which is performed after abdominal injuries. Using this method, you can visualize the inferior vena cava.

Angiography as a method of radiography allows:

• Distinguish a benign tumor from a malignant tumor.
• Confirm liver cirrhosis.
• Determine the type of damage to the vascular bed in mechanical injuries of the abdomen.
• Detect violations in the work of the vascular system of the abdominal cavity.
• Identify the source of LC bleeding, etc.

Angiography as a method of radiography is not prescribed for women during the period of gestation. The result of such a diagnosis can be affected by several factors, including the patient's mobility during angiography, as well as gases and feces in the intestines.

The condition of urological patients is often diagnosed precisely with the help of x-rays. This method allows you to suspect stones or tumors of a benign and malignant nature, Bladder and kidneys.

Plain radiography helps to carry out a differential diagnosis, which allows to exclude gynecological diseases and diseases of the gastrointestinal tract, which often have similar symptoms. But such a study is carried out only in combination with other diagnostic methods, because it is not customary in medical practice to focus only on the results of a survey radiography of the urinary system.

An x-ray of this type will help:

• Determine the localization of the kidneys.
• Reveal some diseases.
• Detect kidney stones.

The quality of x-rays can be affected by gases in the intestines, excess weight patient, voluminous tumors of the ovaries or uterus.

Radiography: tomography of the kidneys

In modern medicine, tomography makes it possible to obtain layered images of human organs. In the case of the kidneys, this method can be performed separately or in combination with excretory urography. This diagnosis is especially informative in the presence of tumors. Thanks to the tomography of the kidneys, it is possible to identify the size, density, boundaries and localization of the tumor, parenchymal rupture, etc.

This method of radiography is prescribed mainly for men. A contrast agent is injected into the urethra, thanks to which the diagnostician can obtain clear images of all its departments. Retrograde urethrography can detect diverticula and various malformations, detect damage, and even assess the condition of the urethra in the postoperative period.

Doctors warn that after carrying out this diagnostic manipulation, the patient may feel unwell during the day, sometimes the body temperature rises. Allergic reactions to the contrast agent are possible.

Retrograde cystography

With this x-ray diagnosis, a contrast agent is injected directly into the bladder. The study allows you to determine the state of the body and identify the gap. Also, the attending physician may recommend cystography if fistulas, diverticula, cysts, vesicoureteral reflux are suspected. A study is also prescribed for infectious diseases of the bladder.

Retrograde cystography is not performed for acute diseases of the bladder, as well as in cases where a rupture of the urethra is traced or an obstacle is determined in it that simply does not allow the catheter to be inserted.

Retrograde ureteropyelography

The method of radiography in the form of retrograde ureteropyelography allows you to determine the integrity of the upper urinary tract, as well as their anatomical features. At the time of cystoscopy, a catheter is inserted into the ureter, where a contrast agent is injected. The image of the upper urinary tract will help the attending physician to diagnose diseases and disorders that could not be confirmed by excretory urography. The quality of the images can be affected by the presence of gases and feces in the intestines.

Such diagnostics is one of the methods of radiography, which makes it possible to detect violations, or rather, most often to obtain clear images of the urinary tract, especially in the situation when retrograde ureteropyelography and / or cystoscopy cannot be performed against the background of ureteral obstruction. Diagnosis is carried out, starting with a puncture (through the skin), after which a safe contrast agent is injected into the pelvicalyceal system.

It is the puncture stage that allows you to collect urine for laboratory tests, to determine the pressure inside the pelvis. Also antegrade pyelography:

• Able to identify the causes that contributed to the blockage of the upper urinary tract. It can be stones, various formations and even blood clots.
• Clarify the diagnosis, which was previously made after ultrasound. For example, it can be hydronephrosis.

Distort the results of such x-ray diagnostics (antegrade pyelography) can be accumulations of gases and feces in the intestine. Excessive body weight of the patient can also affect the result.

Excretory or intravenous urography

This study is an excellent way to obtain x-ray images of the bladder, kidney parenchyma, ureters. Urography of the excretory type will help to assess the anatomical features of the organs and the excretory function of the kidneys.

If the amount of contrast medium is insufficient, then this fact may adversely affect the results of the study. The presence of feces and gases in the intestines also plays an important role, which most often leads to poor image quality.

Arteriography of the kidneys

The X-ray method, namely the arteriography of the kidneys, is performed using a contrast agent, which is injected into the artery. At the moment of advancing (filling) the contrast agent, the diagnostician takes several x-rays to obtain the desired images.

Today, thanks to arteriography, a doctor can fully examine the structure of the vascular system of the kidneys, which is often prescribed before surgery. The X-ray method mentioned above will help determine the provoking factors (stenosis, thrombosis, etc.) of renovascular hypertension. Also, such a diagnosis is indispensable for kidney tumors.

This kind of X-ray examination can help to identify hematomas, parenchymal rupture and even kidney infarction in a patient. The results of the study may be affected by the patient's mobility during the procedure, the presence of feces and gases in the intestines, as well as a recent X-ray examination of the gastrointestinal tract with a contrast agent.

Chest X-ray, or rather bronchography (examination of the tracheobronchial tree) is performed after the use of a contrast agent. Fluid is injected into the lumen of the bronchi and trachea. But such radiography is used extremely rarely, because today the more popular method is CT.

Angiopulmonography

Radiography of the pulmonary circulation is called angiopulmonography. A study is carried out after the introduction of a contrast agent into the pulmonary artery. Manipulation may be prescribed in order to detect or exclude thromboembolism. Also, radiography of this type makes it possible to identify pathological disorders in the pulmonary circulation, as well as to determine the location of a large embolus before its surgical removal.

Phlebography

Radiography of the veins of the lower extremities is called phlebography. This procedure is not particularly relevant today due to the increased radiation exposure. Doctors prefer to prescribe Doppler ultrasound as a diagnosis of the condition of the deep veins of the legs.

Irrigoscopy

X-ray of the intestine, or rather the colon with retrograde injection of contrast fluid, is prescribed to assess its condition. This method allows you to find out about the degree of damage, for example, in Crohn's disease or ulcerative colitis, to detect diverticula and various formations. It is irrigoscopy that allows you to evaluate the anatomical and functional features of the colon, its size and location.

If we compare the x-ray of the intestine with, then the first option is safer, rarely leads to injuries and other complications. It is also important to note that the level of radiation during barium enema is minimal compared to CT of the abdominal cavity.

Thanks to the x-ray of the spine, the doctor can get pictures not only of its individual parts, but of the entire column. Such an informative method can be prescribed at any age, and for diagnosing not only fractures, displacements and other deformities, but also for detecting tumors. Images on x-ray images allow visualization of intervertebral relationships, bone density, irregularities, thickenings, etc.

The column of the spine is conditionally divided into five parts. Of course, all vertebrae are of the same type in their structure, but the fact that the articular surfaces, shapes and sizes here have their own differences should be highlighted.

Radiography of the spine is prescribed for the diagnosis of congenital malformations, displacements, fractures. A research method is prescribed to analyze the condition of the spine in its chronic diseases, for example, arthritis.

Densitometry: X-ray of bones

This diagnostic method is an excellent solution for assessing bone mass. This kind of radiography of the bones allows you to establish their mineral density. The results of the study are transmitted to a computer, thanks to which the volumetric density of bones, their thickness and dimensions are calculated. These data help to assess the level of bone resistance to various kinds of mechanical damage.

Densitometry is a good diagnostic solution that can help assess the risks of developing osteoporosis, as well as the effectiveness of therapy, which is primarily aimed at tissue demineralization. X-ray of bones is contraindicated during pregnancy.

Arthrography: radiography of the joints

With the help of radiography, it is possible to diagnose ruptures of the joint capsules, various lesions inside the joints, and to detect synovial cysts. Conduct a study of the joint after the introduction of a contrast agent or/and air into its cavity. With such a diagnosis, as a rule, several pictures are taken.

From an alternative point of view, today X-rays of the joints can be replaced by MRI. It is also important to know that such a diagnostic method is contraindicated during the period of gestation, with exacerbation of arthritis and infectious diseases.

The main methods of x-ray examination - fluoroscopy and radiography

The purpose of the lesson. To master the basic methods of radiodiagnostics - fluoroscopy and radiography.

Research objects and equipment. X-ray machine, personal protective equipment, translucent screen or cryptoscope, x-ray cassettes, intensifying screens, x-ray film, equipped photo room with the necessary solutions and accessories, drying cabinet for film drying, negatoscope, examined animal.

General characteristics of methods of X-ray diagnostics. Any x-ray examination consists in obtaining an x-ray image of an object and its subsequent study. In the most general form, the X-ray examination system includes: a radiation source, an object of study, a radiation receiver and a specialist performing the study.

The radiation source is an x-ray tube; the object of the study is a sick or, in some cases, a healthy animal. As a radiation receiver, devices or devices are used that convert the energy of an inhomogeneous x-ray beam passing through the body of an animal into an image.

The simplest receiver is a fluoroscopic screen for transillumination (fluoroscopy method). The screen is covered with a special compound (phosphor) that glows when exposed to X-rays. Barium platinum cyanide, activated zinc and cadmium sulfides, etc. are used as a phosphor.

The receiver can also be an X-ray film, the coating emulsion of which contains silver halide compounds. X-ray radiation is capable of decomposing these compounds, therefore, after developing and fixing the exposed film, an image of the object appears on it (this is the basis of the method radiography - taking x-rays).

Instead of a film, a selenium plate charged with electrostatic electricity can be used. Under the action of X-rays in different parts selenium layer, the electrical potential changes and a latent image is formed, which is developed and transferred to paper using a special device. This research method is called electroradiography(xeroradiography).

The most sensitive radiation receiver is a set of scintillation detectors or ionization chambers. They register the intensity of radiation in all parts of the x-ray beam; information is fed into an electronic device connected to a computer. Based on the mathematical processing of the received data, an image of the object appears on the television display. This method is called computed tomography.

With the use of one of these methods always begin x-ray examination.

X-ray. When translucent, an image of the object is obtained on a fluoroscopic screen. The radiation beam leaving the X-ray tube passes through the body of the animal and hits the back of the screen, causing a faint glow of its light-sensitive layer facing the doctor. The image can be viewed only in a darkened room after 10-15 minutes of adaptation. A veterinary radiologist is obliged to use protective equipment: a screen covered with lead glass protects the eye from irradiation; apron and gloves made of X-ray protective material - torso and hands; a screen made of sheet lead or lead rubber - the lower half of the radiologist's body.

The transillumination technique is simple and economical. With the help of fluoroscopy, the movement of organs and the movement of a contrast agent in them are observed, examining the animal in various positions, palpating the desired part of the body. Due to these advantages, fluoroscopy is used very often, but the method also has significant drawbacks. First of all, there is no document that can be analyzed further. In addition, small details of the image are poorly distinguishable on a fluoroscopic screen, and, finally, fluoroscopy is associated with a much greater radiation exposure to the animal and the radiologist under study than radiography.

To eliminate these shortcomings, a special device was designed - an X-ray image amplifier (ARI) with a receiving television device (Fig. 9.8), which perceives the weak glow of the X-ray screen, amplifies it several thousand times, after which the radiologist can view the image through a monocular or it projected onto the transmitting television tube, and then into the receiving television device.

Fluoroscopy using URI and television technology is called x-ray television transillumination, or X-ray vision. Its main advantages: animals shine through in a darkened room; the brightness of the image is significantly increased, which makes it possible to reveal fine details of the object; the radiation load on the animal under study and the radiologist is reduced and, which is very important, it becomes possible to take pictures with

Rice. 9.8. X-ray television attachment: a- scheme of the electron-optical amplifier: 1 - X-ray emitter; 2 - object of study; 3 - input fluorescent screen with a photocathode; 4 - output fluorescent screen; 5- anode;

• 6 - lens; 7- protective lead glass; 8- eyepiece;
• 6 - scheme for forming a video magnetic recording: 1 - x-ray emitter; 2 - object of study; 3 - electron-optical amplifier; 4 - television camera; 5- monitor; 6- video recorder;
• 7 - video monitor

wound, record the image on film, video magnetic tape or discs.

Radiography. This is an X-ray examination method in which an image of an object is obtained on an X-ray film by direct exposure to a radiation beam. x-ray

the film is sensitive not only to X-rays, but also to visible light, so it is placed in a cassette that protects from visible light, but transmits X-rays (Fig. 9.9).

An x-ray beam is directed to the part of the body to be examined. The radiation that has passed through the body of the animal falls on the film. The image becomes visible after film processing (development, fixation). The finished X-ray image is examined in transmitted light on a special device - a negatoscope (Fig. 9.10). A picture of any part of the body is set on a negatoscope in such a way that the proximal sections are turned upwards; when studying radiographs made in lateral projections, the dorsal surface (or head) should be on the left, the volar (plantar) - on the right.

Rice. 9.9.

Rice. 9.10.

Radiography has many advantages. First of all, the method is simple and easy to perform. You can shoot both in the X-ray room, and directly in the operating room, hospital and in the field using portable X-ray machines. The picture shows a clear image of most organs. Some of them, such as bones, lungs, heart, are clearly visible due to the natural contrast; others are clearly visible in the images after artificial contrasting. Images can be stored for a long time, compared with previous and subsequent radiographs, i.e. to study the dynamics of the disease. Indications for radiography are very wide - most radiological studies begin with it.

When radiography, certain rules must be observed: to remove each organ in two mutually perpendicular projections (usually use direct and lateral); during shooting, bring the part of the body under study as close as possible to the film cassette (then the image will turn out to be the clearest and its dimensions will differ little from the true dimensions of the organ under study).

However, there is an X-ray technique in which the object being photographed, on the contrary, is placed relatively far from the film. Under these conditions, due to the diverging X-ray beam, an enlarged image of the organ is obtained. This method of shooting - X-ray with direct magnification of the image - is associated with the use of special "sharp focus" X-ray tubes; it is used to study small details.

Distinguish between survey and sighting radiographs. On survey images, an image of the entire organ is obtained, and on sighting images, only the part of interest to the doctor is obtained.

Electroroentgenography (xeroradiography). In this case, an x-ray image is obtained on semiconductor wafers and then transferred to paper.

During xeroradiography, an X-ray beam that has passed through the body of an animal does not fall on a film cassette, but on a highly sensitive selenium plate charged with static electricity before shooting. Under the influence of radiation, the electric potential of the plate does not change in the same way in different areas, but in accordance with the intensity of the X-ray quanta flux. In other words, a latent image appears on the plate from electrostatic charges.

In the future, the selenium plate is treated with a special developing powder. Negatively charged particles of the latter are attracted to those parts of the selenium layer where positive charges have been preserved, and are not retained in those places that have lost their charge under the action of X-rays. Without any photo processing and in the shortest possible time (30-60 s) on the plate, you can see the X-ray image of the object. Electro-radiographic attachments are equipped with a device that transfers an image from a plate to paper within 2-3 minutes. After that, remove the remains of the developing powder from the plate with a soft cloth and charge it again. More than 1000 images can be obtained on one plate, after which it becomes unsuitable for electro-radiography.

The main advantage of electroroentgenography is that it can be used to quickly obtain big number images without wasting expensive X-ray film, under normal lighting and without a “wet” photo process.

In our country, electro-radiographic devices ERGA-MP (ERGA-01) and ERGA-MT (ERGA-02) are most widely used.

With the development of computer technology in radiography, it became possible to almost instantly acquire an image, activate it, store, restore, and even transmit an image over long distances in digital format. The main advantages of using digital radiography are the availability of the image immediately after shooting, the reduction in irradiation by several times compared to traditional film technology, short exposure (allowing you to avoid dynamic blurring), the complete rejection of consumables and a darkroom, great diagnostic capabilities that allow you to highlight tissue structures, enlarge the fragment of interest and take measurements directly on the computer screen, as well as the ability to organize a compact archive in the form of a database with instant and convenient search. If necessary, the image can be printed on a special film or on paper.

The main disadvantage that limits the use of digital x-ray systems in veterinary medicine is the high cost of equipment and, possibly, some loss in image quality compared to traditional ones.

Chapter 2

Chapter 2

For more than 100 years, rays of a special kind have been known, occupying a large part of the spectrum of electromagnetic waves. On November 8, 1895, Wilhelm Conrad Roentgen (1845-1923), professor of physics at the University of Würzburg, drew attention to an amazing phenomenon. While studying the operation of an electrovacuum (cathode) tube in his laboratory, he noticed that when a high voltage current was applied to its electrodes, the nearby platinum-cyanogen barium began to emit a greenish glow. Such a glow of luminescent substances under the influence of cathode rays emanating from an electrovacuum tube was already known by that time. However, on the X-ray table, the tube was tightly wrapped in black paper during the experiment, and although the platinum-cyanogen barium was at a considerable distance from the tube, its glow resumed with each supply. electric current into the handset (see Fig. 2.1).

Fig.2.1. Wilhelm Conrad Rice. 2.2. X-ray of cis-

Roentgen (1845-1923) ty wife of VK Roentgen Berta

Roentgen came to the conclusion that some kind of rays unknown to science arise in the tube, capable of penetrating through solid bodies and propagating in the air over distances measured in meters. The first radiograph in the history of mankind was the image of the brush of Roentgen's wife (see Fig. 2.2).

Rice. 2.3.Spectrum of electromagnetic radiation

Roentgen's first preliminary report "On a new form of rays" was published in January 1896. In three subsequent public reports in 1896-1897. he formulated all the properties of unknown rays he had discovered and pointed out the technique of their appearance.

In the first days after the publication of Roentgen's discovery, his materials were translated into many languages. foreign languages, including Russian. Petersburg University and the Military Medical Academy already in January 1896 X-rays were used to take pictures of human limbs, and later of other organs. Soon, the inventor of the radio, A. S. Popov, manufactured the first domestic X-ray machine, which functioned in the Kronstadt hospital.

Roentgen was the first among physicists in 1901 to be awarded for his discovery Nobel Prize, which was presented to him in 1909. By the decision of the First International Congress on Radiology in 1906, X-rays were named X-rays.

Within a few years, specialists dedicated to radiology appeared in many countries. X-ray departments and offices appeared in hospitals, scientific societies of radiologists arose in large cities, medical faculties Universities organized the corresponding departments.

X-rays are one of the types of electromagnetic waves that occupy a place in the general wave spectrum between ultraviolet rays and γ-rays. They are different from radio waves, infrared radiation, visible light and ultraviolet radiation shorter wavelength (see Fig. 2.3).

The propagation speed of X-rays is equal to the speed of light - 300,000 km/s.

The following are currently known properties of x-rays. X-rays have penetrating ability. Roentgen reported that the ability of rays to penetrate through various media back

proportional to the specific gravity of these media. Due to the short wavelength, X-rays can penetrate objects that are opaque to visible light.

X-rays are capable absorb and dissipate. When absorbed, part of the X-rays with the longest wavelength disappears, completely transferring their energy to the substance. When scattered, some of the rays deviate from the original direction. Scattered X-ray radiation does not carry useful information. Some of the rays completely pass through the object with a change in their characteristics. Thus, an invisible image is formed.

X-rays, passing through some substances, cause them fluorescence (glow). Substances with this property are called phosphors and are widely used in radiology (fluoroscopy, fluorography).

X-rays provide photochemical action. Like visible light, falling on a photographic emulsion, they act on silver halides, causing chemical reaction silver recovery. This is the basis for image registration on photosensitive materials.

X-rays cause ionization of matter.

X-rays provide biological action, related to their ionizing ability.

X-rays propagate straightforward, therefore, the x-ray image always repeats the shape of the object under study.

X-rays are characteristic polarization- distribution in a certain plane.

Diffraction and interference inherent in x-rays, as well as other electromagnetic waves. X-ray spectroscopy and X-ray structural analysis are based on these properties.

X-rays invisible.

Any X-ray diagnostic system includes 3 main components: an X-ray tube, an object of study (patient) and an X-ray image receiver.

x-ray tube consists of two electrodes (anode and cathode) and a glass bulb (Fig. 2.4).

When a filament current is applied to the cathode, its spiral filament is strongly heated (heated up). A cloud of free electrons appears around it (the phenomenon of thermionic emission). As soon as a potential difference arises between the cathode and anode, free electrons rush to the anode. The speed of the electrons is directly proportional to the magnitude of the voltage. When electrons decelerate in the anode material, part of their kinetic energy goes into the production of X-rays. These rays freely go beyond the X-ray tube and propagate in different directions.

X-rays, depending on the method of occurrence, are divided into primary (stagnation rays) and secondary (characteristic rays).

Rice. 2.4. Schematic diagram of an x-ray tube: 1 - cathode; 2 - anode; 3 - glass flask; 4 - electron flow; 5 - X-ray beam

primary rays. Electrons, depending on the direction of the main transformer, can move in x-ray tubes at different speeds, approaching the speed of light at the highest voltage. Upon impact with the anode, or, as they say, during braking, the kinetic energy of the flight of electrons is converted for the most part into thermal energy, which heats the anode. A smaller part of the kinetic energy is converted into deceleration X-rays. The wavelength of the rays of deceleration depends on the speed of the flight of electrons: the greater it is, the shorter the wavelength. The penetrating power of rays depends on the wavelength (the shorter the wave, the greater its penetrating power).

By changing the voltage of the transformer, one can control the speed of the electrons and obtain either strongly penetrating (so-called hard) or weakly penetrating (so-called soft) x-rays.

Secondary (characteristic) rays. They arise in the process of deceleration of electrons, but the length of their waves depends solely on the structure of the atoms of the anode material.

The fact is that the energy of electron flight in the tube can reach such values ​​that when electrons hit the anode, energy will be released that is sufficient to make the electrons of the inner orbits of the atoms of the anode substance “jump” to the outer orbits. In such cases, the atom returns to its state, because from its outer orbits there will be a transition of electrons to free inner orbits with the release of energy. The excited atom of the anode substance returns to the state of rest. Characteristic radiation arises as a result of changes in the inner electronic layers of atoms. The layers of electrons in an atom are strictly defined

for each element and depend on its place in periodic system Mendeleev. Consequently, the secondary rays received from a given atom will have waves of a strictly defined length, which is why these rays are called characteristic.

Formation electron cloud on the cathode spiral, the flight of electrons to the anode and the production of X-rays are possible only in vacuum conditions. For its creation and serves x-ray tube bulb made of durable glass capable of transmitting x-rays.

As x-ray image receivers can act: X-ray film, selenium plate, fluorescent screen, as well as special detectors (with digital imaging methods).

X-RAY TECHNIQUES

All the numerous methods of X-ray examination are divided into general and special.

To general include techniques designed to study any anatomical regions and performed on general-purpose x-ray machines (fluoroscopy and radiography).

A number of methods should also be referred to the general ones, in which it is also possible to study any anatomical regions, but either special equipment is required (fluorography, radiography with direct image magnification), or additional devices for conventional x-ray machines (tomography, electroroentgenography). Sometimes these techniques are also called private.

To special techniques include those that allow you to get an image on special installations designed to study certain organs and areas (mammography, orthopantomography). Special techniques also include a large group of X-ray contrast studies, in which images are obtained using artificial contrast (bronchography, angiography, excretory urography, etc.).

GENERAL X-RAY EXAMINATION TECHNIQUES

Fluoroscopy- a research technique in which an image of an object is obtained on a luminous (fluorescent) screen in real time. Some substances fluoresce intensely when exposed to x-rays. This fluorescence is used in X-ray diagnostics using cardboard screens coated with a fluorescent substance.

The patient is installed (lay down) on a special tripod. X-rays, passing through the body of the patient (the area of ​​interest to the researcher), fall on the screen and cause it to glow - fluorescence. The fluorescence of the screen is not equally intense - it is the brighter, the more X-rays hit one or another point of the screen. On screen

the fewer rays hit, the more dense obstacles will be on their way from the tube to the screen (for example, bone tissue), and also the thicker the tissue through which the rays pass.

The glow of the fluorescent screen is very weak, so X-rays were taken in the dark. The image on the screen was poorly distinguishable, small details were not differentiated, and the radiation exposure in such a study was quite high.

As an improved method of fluoroscopy, X-ray television transmission is used with the help of an X-ray image amplifier - an image intensifier tube (IOC) and a closed-circuit television system. In the image intensifier tube, the visible image on the fluorescent screen is amplified, converted into an electrical signal, and displayed on the display screen.

The x-ray image on the display, like a conventional television image, can be studied in a lighted room. Radiation exposure to the patient and staff when using image intensifier tubes is much less. The telesystem allows you to record all stages of the study, including the movement of organs. In addition, the image can be transmitted via a TV channel to monitors located in other rooms.

During X-ray examination, a positive planar black-and-white summation image is formed in real time. When moving the patient relative to the X-ray emitter, they speak of polypositional, and when moving the X-ray emitter relative to the patient, they speak of a polyprojective study; both of them allow to obtain more complete information about the pathological process.

However, fluoroscopy, both with and without an image intensifier tube, has a number of disadvantages that narrow the scope of the method. First, the radiation exposure from fluoroscopy remains relatively high (much higher than from radiography). Secondly, the technique has a low spatial resolution (the ability to consider and evaluate fine details is lower than with radiography). In this regard, it is advisable to supplement fluoroscopy with the production of images. It is also necessary to objectify the results of the study and the possibility of their comparison in the dynamic monitoring of the patient.

Radiography- This is a technique of X-ray examination, in which a static image of an object is obtained, fixed on any information carrier. Such carriers can be X-ray film, photographic film, digital detector, etc. An image of any anatomical region can be obtained on radiographs. Pictures of the entire anatomical region (head, chest, abdomen) are called review(Fig. 2.5). Pictures showing a small part of the anatomical region that is of most interest to the doctor are called aiming(Fig. 2.6).

Some organs are clearly visible in the images due to the natural contrast (lungs, bones) (see Fig. 2.7); others (stomach, intestines) are clearly displayed on radiographs only after artificial contrasting (see Fig. 2.8).

Rice. 2.5.Plain radiograph of the lumbar spine in lateral projection. Compression but-os-ringed fracture of the L1 vertebral body

Rice. 2.6.

Periapical radiograph of L1 vertebra in lateral view

Passing through the object of study, X-ray radiation is delayed to a greater or lesser extent. Where the radiation is delayed more, areas are formed shading; where is less enlightenment.

The x-ray image may be negative or positive. So, for example, in a negative image, the bones look light, air - dark, in a positive image - vice versa.

The x-ray image is black and white and planar (summation).

Advantages of radiography over fluoroscopy:

Great resolution;

Possibility of evaluation by many researchers and retrospective study of the image;

The possibility of long-term storage and comparison of images with repeated images in the process of dynamic monitoring of the patient;

Reducing radiation exposure to the patient.

The disadvantages of radiography include an increase in material costs when using it (radiographic film, photoreagents, etc.) and obtaining the desired image not immediately, but after a certain time.

The radiography technique is available to all medical institutions and is used everywhere. X-ray machines of various types make it possible to perform radiography not only in the conditions of the X-ray room, but also outside it (in the ward, in the operating room, etc.), as well as in non-stationary conditions.

The development of computer technology has made it possible to develop a digital (digital) method for obtaining an x-ray image (from the English. digital- "number"). In digital devices, an x-ray image from an image intensifier tube enters a special device - an analog-to-digital converter (ADC), in which an electrical signal that carries information about an x-ray image is encoded into digital form. Entering then the computer, the digital information is processed in it according to pre-compiled programs, the choice of which depends on the objectives of the study. The transformation of a digital image into an analog, visible one takes place in a digital-to-analog converter (DAC), the function of which is opposite to the ADC.

The main advantages of digital radiography over traditional radiography are: fast image acquisition, wide possibilities for its post-processing processing (brightness and contrast correction, noise suppression, electronic magnification of the image of the area of ​​interest, predominant selection of bone or soft tissue structures, etc.), the absence of a photolaboratory process, and electronic archiving of images.

In addition, the computerization of X-ray equipment allows you to quickly transfer images over long distances without loss of quality, including to other medical institutions.

Rice. 2.7.Radiographs of the ankle joint in frontal and lateral projections

Rice. 2.8.X-ray of the colon, contrasted with a suspension of barium sulfate (irrigogram). Norm

Fluorography- photographing an x-ray image from a fluorescent screen onto photographic film of various formats. Such an image is always scaled down.

In terms of information content, fluorography is inferior to radiography, but when using large-frame fluorograms, the difference between these methods becomes less significant. In this regard, in medical institutions, in a number of patients with respiratory diseases, fluorography can replace radiography, especially during repeated studies. This type of fluoroscopy is called diagnostic.

The main purpose of fluorography, associated with the speed of its implementation (it takes about 3 times less time to perform a fluorogram than to perform a radiograph), are mass examinations to detect latent lung diseases. (preventive, or check, fluorography).

Fluorographic devices are compact, they can be mounted in a car body. This makes it possible to conduct mass examinations in areas where X-ray diagnostic equipment is not available.

Currently, film fluorography is increasingly being replaced by digital. The term "digital fluorographs" is to a certain extent conditional, since these devices do not photograph the x-ray image on film, i.e., fluorograms are not performed in the usual sense of the word. In fact, these fluorographs are digital radiographic devices designed primarily (but not exclusively) for examining the organs of the chest cavity. Digital fluorography has all the advantages inherent in digital radiography in general.

X-ray with direct magnification can only be used in the presence of special X-ray tubes in which the focal spot (the area from which X-rays come from the emitter) is very small (0.1-0.3 mm 2). An enlarged image is obtained by bringing the object under study closer to the x-ray tube without changing the focal length. As a result, radiographs show finer details that are indistinguishable in conventional images. The technique is used in the study of peripheral bone structures (hands, feet, etc.).

Electroradiography- a technique in which a diagnostic image is obtained not on an x-ray film, but on the surface of a selenium plate with transfer to paper. A plate uniformly charged with static electricity is used instead of a film cassette and, depending on the different amount of ionizing radiation that has hit different points on its surface, is discharged differently. A finely dispersed coal powder is sprayed onto the surface of the plate, which, according to the laws of electrostatic attraction, is distributed unevenly over the surface of the plate. A sheet of writing paper is placed on the plate, and the image is transferred to the paper as a result of the adhesion of carbon

powder. A selenium plate, unlike a film, can be used repeatedly. The technique is fast, economical, does not require a darkened room. In addition, selenium plates in the uncharged state are indifferent to the effects of ionizing radiation and can be used when working in conditions of increased radiation background(X-ray film will become unusable under these conditions).

In general, electroroentgenography is only slightly inferior to film radiography in its information content, surpassing it in the study of bones (Fig. 2.9).

Linear tomography- method of layer-by-layer X-ray examination.

Rice. 2.9.An electroroentgenogram of the ankle joint in direct projection. Fracture of the fibula

As already mentioned, the summation image of the entire thickness of the studied part of the body is visible on the radiograph. Tomography serves to obtain an isolated image of structures located in the same plane, as if dividing the summation image into separate layers.

The effect of tomography is achieved due to the continuous movement during the shooting of two or three components of the x-ray system: x-ray tube (emitter) - patient - image receiver. Most often, the emitter and image receiver are moved, and the patient is motionless. The emitter and image receiver move in an arc, a straight line, or a more complex path, but always in opposite directions. With such a displacement, the image of most details on the tomogram turns out to be smeared, blurry, fuzzy, and the formations located at the level of the center of rotation of the emitter-receiver system are displayed most clearly (Fig. 2.10).

Linear tomography has a special advantage over radiography.

when organs are examined with dense pathological zones formed in them, completely obscuring certain areas of the image. In some cases, it helps to determine the nature of the pathological process, to clarify its localization and prevalence, to identify small pathological foci and cavities (see Fig. 2.11).

Structurally, tomographs are made in the form of an additional tripod, which can automatically move the X-ray tube along the arc. When the level of the center of rotation of the emitter - receiver changes, the depth of the resulting cut will change. The thickness of the studied layer is the smaller, the greater the amplitude of motion of the system mentioned above. If they choose very

small angle of movement (3-5°), then get the image of a thick layer. This type of linear tomography is called - zonography.

Linear tomography is widely used, especially in medical institutions that do not have computed tomography. The most common indications for tomography are diseases of the lungs and mediastinum.

SPECIAL TECHNIQUES

RADIOLOGICAL

RESEARCH

Orthopantomography- this is a variant of zoning, which allows you to get a detailed planar image of the jaws (see Fig. 2.12). In this case, a separate image of each tooth is achieved by sequentially shooting them with a narrow beam.

Rice. 2.10. Scheme for obtaining a tomographic image: a - the object under study; b - tomographic layer; 1-3 - sequential positions of the X-ray tube and the radiation receiver in the process of research

lump of x-rays on separate sections of the film. The conditions for this are created by a synchronous circular motion around the head of the patient of the x-ray tube and the image receiver, installed at opposite ends of the rotary stand of the device. The technique allows you to explore other parts of the facial skeleton (paranasal sinuses, eye sockets).

Mammography- X-ray examination of the breast. It is performed to study the structure of the mammary gland when seals are found in it, as well as for a preventive purpose. milk jelly-

za is a soft tissue organ; therefore, to study its structure, it is necessary to use very small values ​​of the anode voltage. There are special x-ray machines - mammographs, where x-ray tubes are installed with a focal spot the size of a fraction of a millimeter. They are equipped with special stands for laying the mammary gland with a device for its compression. This makes it possible to reduce the thickness of the gland tissue during the examination, thereby improving the quality of mammograms (see Fig. 2.13).

Techniques using artificial contrast

In order for organs invisible in ordinary photographs to be displayed on radiographs, they resort to the technique of artificial contrasting. The technique consists in the introduction into the body of substances,

Rice. 2.11. Linear tomogram of the right lung. At the apex of the lung there is a large air cavity with thick walls.

which absorb (or, conversely, transmit) radiation much stronger (or weaker) than the organ under study.

Rice. 2.12. Orthopantomogram

Substances with a low relative density (air, oxygen, carbon dioxide, nitrous oxide), or with a large atomic mass (suspensions or solutions of salts of heavy metals and halides). The former absorb X-rays to a lesser extent than the anatomical structures (negative) the second - to a greater extent (positive). If, for example, air is introduced into the abdominal cavity (artificial pneumoperitoneum), then the outlines of the liver, spleen, gallbladder, and stomach are clearly distinguished against its background.

Rice. 2.13. Radiographs of the mammary gland in craniocaudal (a) and oblique (b) projections

For the study of organ cavities, high-atomic contrast agents are usually used, most often an aqueous suspension of barium sulfate and iodine compounds. These substances, largely delaying X-rays, give an intense shadow on the pictures, by which one can judge the position of the organ, the shape and size of its cavity, and the outlines of its inner surface.

There are two ways of artificial contrasting with the help of highly atomic substances. The first is the direct injection of a contrast agent into the cavity of an organ - the esophagus, stomach, intestines, bronchi, blood or lymphatic vessels, urinary tract, cavitary systems of the kidneys, uterus, salivary ducts, fistulous tracts, cerebrospinal fluid spaces of the brain and spinal cord, etc. d.

The second method is based on specific ability individual organs to concentrate certain contrast agents. For example, the liver, gallbladder, and kidneys concentrate and excrete some of the iodine compounds introduced into the body. After the introduction of such substances to the patient in the pictures after a certain time, the bile ducts, gall bladder, cavitary systems of the kidneys, ureters, bladder are distinguished.

The technique of artificial contrasting is currently the leading one in X-ray examination of most internal organs.

In x-ray practice, 3 types of radiopaque agents (RKS) are used: iodine-containing soluble, gaseous, aqueous suspension of barium sulfate. The main tool for the study of the gastrointestinal tract is an aqueous suspension of barium sulfate. For the study of blood vessels, heart cavities, urinary tract, water-soluble iodine-containing substances are used, which are injected either intravascularly or into the cavity of organs. Gases are almost never used as contrast agents.

When choosing contrast agents for research, RCD should be evaluated from the standpoint of the severity of the contrasting effect and harmlessness.

The harmlessness of RCM, in addition to the obligatory biological and chemical inertness, depends on their physical characteristics, of which the most significant are osmolarity and electrical activity. Os-molarity is determined by the number of ions or PKC molecules in solution. Regarding blood plasma, the osmolarity of which is 280 mOsm / kg H 2 O, contrast agents can be high osmolar (more than 1200 mOsm / kg H 2 O), low osmolar (less than 1200 mOsm / kg H 2 O) or isoosmolar (equivalent in osmolarity to blood) .

High osmolarity adversely affects the endothelium, erythrocytes, cell membranes, proteins, so low-osmolar RCS should be preferred. Optimal RCS, isoosmolar with blood. It should be remembered that the osmolarity of PKC, both lower and higher than the osmolarity of blood, makes these drugs adversely affect blood cells.

In terms of electrical activity, radiopaque preparations are divided into: ionic, decomposing in water into electrically charged particles, and non-ionic, electrically neutral. The osmolarity of ionic solutions, due to the greater content of particles in them, is twice that of non-ionic ones.

Non-ionic contrast agents have a number of advantages compared to ionic ones: significantly lower (3-5 times) overall toxicity, give a much less pronounced vasodilation effect, cause

less deformation of erythrocytes and much less release of histamine, activate the complement system, inhibit cholinesterase activity, which reduces the risk of negative side effects.

Thus, non-ionic RCMs provide the greatest assurance in terms of both safety and contrast quality.

The widespread introduction of contrasting various organs with these preparations has led to the emergence of numerous methods of X-ray examination, which significantly increase the diagnostic capabilities of the X-ray method.

Diagnostic pneumothorax- X-ray examination of the respiratory organs after the introduction of gas into the pleural cavity. It is performed in order to clarify the localization of pathological formations located on the border of the lung with neighboring organs. With the advent of the CT method, it is rarely used.

Pneumomediastinography- X-ray examination of the mediastinum after the introduction of gas into its tissue. It is performed in order to clarify the localization of pathological formations (tumors, cysts) identified in the images and their spread to neighboring organs. With the advent of the CT method, it is practically not used.

Diagnostic pneumoperitoneum- X-ray examination of the diaphragm and organs of the abdominal cavity after the introduction of gas into the peritoneal cavity. It is performed in order to clarify the localization of pathological formations identified in the images against the background of the diaphragm.

pneumoretroperitoneum- a technique for X-ray examination of organs located in the retroperitoneal tissue by introducing gas into the retroperitoneal tissue in order to better visualize their contours. With the introduction of ultrasound, CT and MRI into clinical practice, it is practically not used.

Pneumoren- X-ray examination of the kidney and the adjacent adrenal gland after the introduction of gas into the perirenal tissue. Currently, it is extremely rare.

Pneumopyelography- study of the cavitary system of the kidney after filling it with gas through the ureteral catheter. It is currently used mainly in specialized hospitals for the detection of intrapelvic tumors.

Pneumomyelography- X-ray examination of the subarachnoid space of the spinal cord after gas contrasting. It is used to diagnose pathological processes in the area of ​​the spinal canal, causing narrowing of its lumen (herniated discs, tumors). Rarely used.

Pneumoencephalography- X-ray examination of the cerebrospinal fluid spaces of the brain after contrasting with gas. Once introduced into clinical practice, CT and MRI are rarely performed.

Pneumoarthrography- X-ray examination of large joints after the introduction of gas into their cavity. Allows you to study the articular cavity, identify intra-articular bodies in it, detect signs of damage to the menisci of the knee joint. Sometimes it is supplemented by the introduction into the joint cavity

water-soluble RCS. It is widely used in medical institutions when it is impossible to perform MRI.

Bronchography- a technique for X-ray examination of the bronchi after their artificial contrasting of the RCS. Allows you to identify various pathological changes in the bronchi. It is widely used in medical institutions when CT is not available.

Pleurography- X-ray examination of the pleural cavity after its partial filling with a contrast agent in order to clarify the shape and size of pleural encystation.

Sinography- X-ray examination of the paranasal sinuses after their filling with the RCS. It is used when there are difficulties in interpreting the cause of shading of the sinuses on radiographs.

Dacryocystography- X-ray examination of the lacrimal ducts after their filling with the RCS. It is used to study the morphological state of the lacrimal sac and the patency of the lacrimal canal.

Sialography- X-ray examination of the ducts of the salivary glands after their filling with the RCS. It is used to assess the condition of the ducts of the salivary glands.

X-ray of the esophagus, stomach and duodenum- is carried out after their gradual filling with a suspension of barium sulfate, and, if necessary, with air. It necessarily includes polypositional fluoroscopy and the performance of survey and sighting radiographs. It is widely used in medical institutions to detect various diseases of the esophagus, stomach and duodenum (inflammatory and destructive changes, tumors, etc.) (see Fig. 2.14).

Enterography- X-ray examination of the small intestine after filling its loops with a suspension of barium sulfate. Allows you to get information about the morphological and functional state of the small intestine (see Fig. 2.15).

Irrigoscopy- X-ray examination of the colon after retrograde contrasting of its lumen with a suspension of barium sulfate and air. It is widely used to diagnose many diseases of the colon (tumors, chronic colitis, etc.) (see Fig. 2.16).

Cholecystography- X-ray examination of the gallbladder after the accumulation of a contrast agent in it, taken orally and excreted with bile.

Excretory cholegraphy- X-ray examination of the biliary tract, contrasted with iodine-containing drugs administered intravenously and excreted in the bile.

Cholangiography- X-ray examination of the bile ducts after the introduction of the RCS into their lumen. It is widely used to clarify the morphological state of the bile ducts and to identify stones in them. It can be performed during surgery (intraoperative cholangiography) and in the postoperative period (through a drainage tube) (see Fig. 2.17).

Retrograde cholangiopancreaticography- X-ray examination of the bile ducts and pancreatic duct after injection

into their lumen of a contrast agent under X-ray endoscopic control (see Fig. 2.18).

Rice. 2.14. X-ray of the stomach, contrasted with a suspension of barium sulfate. Norm

Rice. 2.16. Irrigogram. Colon cancer. The lumen of the caecum is sharply narrowed, the contours of the affected area are uneven (indicated by arrows in the picture)

Rice. 2.15. X-ray of the small intestine, contrasted with a suspension of barium sulfate (enterogram). Norm

Rice. 2.17. Antegrade cholangiogram. Norm

Excretory urography- X-ray examination of the urinary organs after intravenous administration of RCS and its excretion by the kidneys. A widely used research technique that allows you to study the morphological and functional state of the kidneys, ureters and bladder (see Fig. 2.19).

Retrograde ureteropyelography- X-ray examination of the ureters and cavitary systems of the kidneys after filling them with RCS through a ureteral catheter. Compared with excretory urography, it provides more complete information about the state of the urinary tract

as a result of their better filling with a contrast agent injected under low pressure. Widely used in specialized urological departments.

Rice. 2.18. Retrograde cholangiopancreaticogram. Norm

Rice. 2.19. Excretory urogram. Norm

Cystography- X-ray examination of the bladder filled with RCS (see Fig. 2.20).

urethrography- X-ray examination of the urethra after its filling with the RCS. Allows you to get information about the patency and morphological state of the urethra, identify its damage, strictures, etc. It is used in specialized urological departments.

Hysterosalpingography- X-ray examination of the uterus and fallopian tubes after filling their lumen with the RCS. It is widely used primarily to assess the patency of the fallopian tubes.

Positive myelography- X-ray examination of the subarachnoid spaces of the spinal

Rice. 2.20. Descending cystogram. Norm

brain after administration of water-soluble RCS. With the advent of MRI, it is rarely used.

Aortography- X-ray examination of the aorta after the introduction of the RCS into its lumen.

Arteriography- X-ray examination of the arteries with the help of RCS introduced into their lumen, spreading through the blood flow. Some private methods of arteriography (coronary angiography, carotid angiography), being highly informative, are at the same time technically complex and unsafe for the patient, and therefore are used only in specialized departments (Fig. 2.21).

Rice. 2.21. Carotid angiograms in direct (a) and lateral (b) projections. Norm

Cardiography- X-ray examination of the cavities of the heart after the introduction of the RCS into them. Currently, it finds limited use in specialized cardiac surgical hospitals.

Angiopulmonography- X-ray examination of the pulmonary artery and its branches after the introduction of RCS into them. Despite the high information content, it is unsafe for the patient, and therefore in last years preference is given to computed tomographic angiography.

Phlebography- X-ray examination of the veins after the introduction of the RCS into their lumen.

Lymphography- X-ray examination of the lymphatic tract after the introduction of the RCS into the lymphatic channel.

Fistulography- X-ray examination of the fistulous tracts after their filling by the RCS.

Vulnerography- X-ray examination of the wound channel after filling it with RCS. It is more often used for blind wounds of the abdomen, when other research methods do not allow to establish whether the wound is penetrating or non-penetrating.

Cystography- contrast x-ray examination of cysts of various organs in order to clarify the shape and size of the cyst, its topographic location and the state of the inner surface.

Ductography- contrast x-ray examination of the milk ducts. Allows you to assess the morphological state of the ducts and identify small breast tumors with intraductal growth, indistinguishable on mammograms.

INDICATIONS FOR THE USE OF THE RADIOLOGICAL METHOD

Head

1. Anomalies and malformations of the bone structures of the head.

2. Head injury:

Diagnosis of fractures of the bones of the brain and facial parts of the skull;

Identification of foreign bodies of the head.

3. Brain tumors:

Diagnosis of pathological calcifications characteristic of tumors;

Identification of the tumor vasculature;

Diagnosis of secondary hypertensive-hydrocephalic changes.

4. Diseases of the vessels of the brain:

Diagnosis of aneurysms and vascular malformations (arterial aneurysms, arterio-venous malformations, arterio-sinus anastomoses, etc.);

Diagnosis of stenosing and occlusive diseases of the vessels of the brain and neck (stenosis, thrombosis, etc.).

5. Diseases of the ENT organs and the organ of vision:

Diagnosis of tumor and non-tumor diseases.

6. Diseases of the temporal bone:

Diagnosis of acute and chronic mastoiditis.

Breast

1. Chest injury:

Diagnosis of chest injuries;

Identification of fluid, air or blood in the pleural cavity (pneumo-, hemothorax);

Identification of pulmonary contusions;

Detection of foreign bodies.

2. Tumors of the lungs and mediastinum:

Diagnosis and differential diagnosis of benign and malignant tumors;

Assessment of the state of regional lymph nodes.

3. Tuberculosis:

Diagnosis of various forms of tuberculosis;

Assessment of the state of intrathoracic lymph nodes;

Differential diagnosis with other diseases;

Evaluation of the effectiveness of treatment.

4. Diseases of the pleura, lungs and mediastinum:

Diagnosis of all forms of pneumonia;

Diagnosis of pleurisy, mediastinitis;

Diagnosis of pulmonary embolism;

Diagnosis of pulmonary edema;

5. Examination of the heart and aorta:

Diagnosis of acquired and congenital malformations of the heart and aorta;

Diagnosis of heart damage in case of chest and aortic injury;

Diagnosis of various forms of pericarditis;

Assessment of the state of coronary blood flow (coronary angiography);

Diagnosis of aortic aneurysms.

Stomach

1. Abdominal injury:

Identification of free gas and liquid in the abdominal cavity;

Detection of foreign bodies;

Establishment of the penetrating nature of the abdominal wound.

2. Examination of the esophagus:

Diagnosis of tumors;

Detection of foreign bodies.

3. Examination of the stomach:

Diagnosis of inflammatory diseases;

Diagnosis of peptic ulcer;

Diagnosis of tumors;

Detection of foreign bodies.

4. Intestinal examination:

Diagnosis of intestinal obstruction;

Diagnosis of tumors;

Diagnosis of inflammatory diseases.

5. Examination of the urinary organs:

Identification of anomalies and development options;

Urolithiasis disease;

Identification of stenotic and occlusive diseases of the renal arteries (angiography);

Diagnosis of stenotic diseases of the ureters, urethra;

Diagnosis of tumors;

Detection of foreign bodies;

Assessment of excretory function of the kidneys;

Monitoring the effectiveness of the treatment.

Taz

1. Injury:

Diagnosis of pelvic fractures;

Diagnosis of ruptures of the bladder, posterior urethra and rectum.

2. Congenital and acquired deformities of the pelvic bones.

3. Primary and secondary tumors of the pelvic bones and pelvic organs.

4. Sacroiliitis.

5. Diseases of the female genital organs:

Evaluation of the patency of the fallopian tubes.

Spine

1. Anomalies and malformations of the spine.

2. Injury of the spine and spinal cord:

Diagnosis of various types of fractures and dislocations of the vertebrae.

3. Congenital and acquired spinal deformities.

4. Tumors of the spine and spinal cord:

Diagnosis of primary and metastatic tumors of bone structures of the spine;

Diagnosis of extramedullary tumors of the spinal cord.

5. Degenerative-dystrophic changes:

Diagnosis of spondylosis, spondylarthrosis and osteochondrosis and their complications;

Diagnosis of herniated discs;

Diagnosis of functional instability and functional block of the vertebrae.

6. Inflammatory diseases of the spine (specific and nonspecific spondylitis).

7. Osteochondropathy, fibrous osteodystrophy.

8. Densitometry in systemic osteoporosis.

limbs

1. Injuries:

Diagnosis of fractures and dislocations of limbs;

Monitoring the effectiveness of the treatment.

2. Congenital and acquired limb deformities.

3. Osteochondropathy, fibrous osteodystrophy; congenital systemic diseases of the skeleton.

4. Diagnosis of tumors of bones and soft tissues of the extremities.

5. Inflammatory diseases of bones and joints.

6. Degenerative-dystrophic diseases of the joints.

7. Chronic diseases of the joints.

8. Stenosing and occlusive diseases of the vessels of the extremities.