X-ray study of the internal structure of objects. X-ray - what is it? How is radiography of the spine, joints, and various organs done? Contraindications for x-ray examination

Modern methods of X-ray studies are classified primarily by the type of hardware visualization of X-ray projection images. That is, the main types of X-ray diagnostics are differentiated by the fact that each is based on the use of one of several existing types of X-ray detectors: X-ray film, fluorescent screen, electron-optical X-ray converter, digital detector, etc.

Classification of X-ray diagnostic methods

In modern radiology, there are general research methods and special or auxiliary ones. The practical application of these methods is possible only with the use of X-ray machines. Common methods include:

radiography,
fluoroscopy,
teleradiography,
digital radiography,
fluorography,
linear tomography,
CT scan,
contrast radiography.

Special studies include an extensive group of methods that allow solving a wide variety of diagnostic problems, and there are invasive and non-invasive methods. Invasive ones are associated with the introduction into various cavities (alimentary canal, vessels) of instruments (radio-opaque catheters, endoscopes) for diagnostic procedures under the control of x-rays. Non-invasive methods do not involve the introduction of instruments.

Each of the above methods has its own advantages and disadvantages, and hence certain limits of diagnostic capabilities. But all of them are characterized by high information content, ease of implementation, accessibility, the ability to complement each other and generally occupy one of the leading places in medical diagnostics: in more than 50% of cases, diagnosis is impossible without the use of X-ray diagnostics.

Radiography

The radiography method is the obtaining of fixed images of an object in the X-ray spectrum on a material sensitive to it (X-ray film, digital detector) according to the principle of inverse negative. The advantage of the method is a small radiation exposure, high image quality with clear detail.

The disadvantage of radiography is the impossibility of observing dynamic processes and the long processing period (in the case of film radiography). To study dynamic processes, there is a method of frame-by-frame image fixation - X-ray cinematography. It is used to study the processes of digestion, swallowing, respiration, blood circulation dynamics: X-ray phase cardiography, X-ray pneumopolygraphy.

Fluoroscopy

The method of fluoroscopy is the obtaining of an x-ray image on a fluorescent (luminescent) screen according to the direct negative principle. Allows you to study dynamic processes in real time, optimize the position of the patient in relation to the X-ray beam during the study. X-ray allows you to evaluate both the structure of the organ and its functional state: contractility or extensibility, displacement, filling with a contrast agent and its passage. The multiprojectivity of the method allows you to quickly and accurately identify the localization of existing changes.

A significant drawback of fluoroscopy is a large radiation load on the patient and the examining physician, as well as the need to conduct the procedure in a dark room.

X-ray television

Telefluoroscopy is a study that uses the conversion of an X-ray image into a television signal using an image intensifier tube or amplifier (EOP). A positive x-ray image is displayed on a TV monitor. The advantage of the technique is that it significantly eliminates the shortcomings of conventional fluoroscopy: radiation exposure to the patient and staff is reduced, image quality (contrast, brightness, high resolution, image magnification) can be controlled, the procedure is performed in a bright room.

Fluorography

The fluorography method is based on photographing a full-length shadow X-ray image from a fluorescent screen onto film. Depending on the film format, analog fluorography can be small-, medium- and large-frame (100x100 mm). It is used for mass preventive studies, mainly of the chest organs. In modern medicine, more informative large-frame fluorography or digital fluorography is used.

Contrast radiodiagnosis

Contrast X-ray diagnostics is based on the use of artificial contrasting by introducing radiopaque substances into the body. The latter are divided into X-ray positive and X-ray negative. X-ray positive substances basically contain heavy metals - iodine or barium, therefore they absorb radiation more strongly than soft tissues. X-ray negative substances are gases: oxygen, nitrous oxide, air. They absorb X-rays less than soft tissues, thereby creating a contrast with respect to the organ being examined.

Artificial contrasting is used in gastroenterology, cardiology and angiology, pulmonology, urology and gynecology, used in ENT practice and in the study of bone structures.

How an x-ray machine works

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:

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 in 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 at 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 using 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 (imaging-guided palpation, targeted history), etc.

Disadvantages: relatively large radiation exposure to the patient and attendants; low throughput during the doctor's working hours; 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 the 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 (the chemical composition of these organs), size, and 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 iodine compounds - 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 radiocontrast 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, studies of fistulas, 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:

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 of a similar 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, inject 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 carried out 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, the introduction of the RCS should be immediately stopped, the patient should be placed in the Trendelenburg position, artificial respiration and chest compressions should be started, 0.1% - 0.5 ml of adrenaline solution should be injected intravenously and the resuscitation team should be called for possible tracheal intubation, artificial respiration and artificial respiration. carrying out further therapeutic measures.

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X-ray diagnostic method. Types of x-ray examination of bones

X-ray of bones is one of the most common research conducted in modern medical practice. Most people are familiar with this procedure because the possibilities for applying this method are very extensive. List of indications for x-ray bones includes a large number of diseases. Only injuries and fractures of the limbs require repeated X-ray examinations.

X-ray of the bones is carried out using various equipment, there is also a variety of methods for this study. The use of the type of x-ray examination depends on the specific clinical situation, the age of the patient, the underlying disease and concomitant factors. Radiation diagnostic methods are indispensable in the diagnosis of diseases of the skeletal system and play a major role in the diagnosis.

There are the following types of x-ray examination of bones:

film radiography;
digital radiography;
x-ray densitometry;
x-ray of bones using contrast agents and some other methods.

What is an x-ray?

X-ray is one of the types of electromagnetic radiation. This type of electromagnetic energy was discovered in 1895. Electromagnetic radiation also includes sunlight, as well as light from any artificial lighting. X-rays are used not only in medicine, but are also found in ordinary nature. About 1% of the Sun's radiation reaches the Earth in the form of X-rays, which forms a natural radiation background.

The artificial production of X-rays was made possible by Wilhelm Conrad Roentgen, after whom they are named. He was also the first to discover the possibility of their use in medicine for "transillumination" of internal organs, primarily bones. Subsequently, this technology developed, new ways of using X-ray radiation appeared, and the radiation dose decreased.

One of the negative properties of X-ray radiation is its ability to cause ionization in the substances through which it passes. Because of this, X-rays are called ionizing radiation. In high doses, X-rays can lead to radiation sickness. For the first decades after the discovery of X-rays, this feature was unknown, which led to diseases in both doctors and patients. However, today the dose of X-ray radiation is carefully controlled and it is safe to say that the harm from X-ray radiation can be neglected.

The principle of obtaining an x-ray

Three components are needed to take an x-ray. The first one is an X-ray source. The source of X-rays is an X-ray tube. In it, under the influence of an electric current, certain substances interact and release energy, from which most of it is released in the form of heat, and a small part in the form of X-rays. X-ray tubes are part of all x-ray machines and require significant cooling.

The second component for obtaining a snapshot is the object under study. Depending on its density, partial absorption of X-rays occurs. Due to the difference in the tissues of the human body, X-ray radiation of different power penetrates outside the body, which leaves various spots on the picture. Where the X-ray radiation was absorbed to a greater extent, shadows remain, and where it passed almost unchanged, enlightenments form.

The third component for taking an x-ray is the x-ray receiver. It can be film or digital ( X-ray sensitive sensor). The most commonly used receiver today is X-ray film. It is treated with a special emulsion containing silver, which changes when X-rays hit it. The areas of enlightenment in the picture have a dark tint, and the shadows have a white tint. Healthy bones have a high density and leave a uniform shadow on the image.

Digital and film x-ray of bones

The first methods of X-ray research implied the use of a photosensitive screen or film as a receiving element. Today, X-ray film is the most commonly used X-ray detector. However, in the coming decades, digital radiography will completely replace film radiography, as it has a number of undeniable advantages. In digital radiography, sensors that are sensitive to x-rays are the receiving element.

Digital radiography has the following advantages over film radiography:

the ability to reduce the radiation dose due to the higher sensitivity of digital sensors;
increase the accuracy and resolution of the image;
simplicity and speed of obtaining a picture, no need to process a photosensitive film;
ease of storage and processing of information;
the ability to quickly transfer information.

The only drawback of digital radiography is the somewhat higher cost of the equipment compared to conventional radiography. Because of this, not all medical centers can find this equipment. Whenever possible, patients are advised to perform a digital x-ray, as it provides more complete diagnostic information and, at the same time, is less harmful.

X-ray of bones with contrast agent

Radiography of the bones of the extremities can be performed using contrast agents. Unlike other body tissues, bones have a high natural contrast. Therefore, contrast agents are used to clarify the formations adjacent to the bones - soft tissues, joints, blood vessels. These x-ray techniques are not used so often, but in some clinical situations they are indispensable.

There are the following radiopaque techniques for examining bones:

Fistulography. This technique involves filling the fistulous passages with contrast agents ( iodolipol, barium sulfate). Fistulas form in the bones in inflammatory conditions such as osteomyelitis. After the study, the substance is removed from the fistula with a syringe.
Pneumography. This study involves the introduction of gas ( air, oxygen, nitrous oxide) with a volume of about 300 cubic centimeters into soft tissues. Pneumography is performed, as a rule, with traumatic injuries combined with crushing of soft tissues, comminuted fractures.
Arthrography. This method involves filling the joint cavity with a liquid radiopaque preparation. The amount of contrast agent depends on the volume of the joint cavity. Most often, arthrography is performed on the knee joint. This technique allows you to assess the state of the articular surfaces of the bones included in the joint.
Bone angiography. This type of study involves the introduction of a contrast agent into the vascular bed. The study of bone vessels is used in tumor formations, to clarify the features of its growth and blood supply. In malignant tumors, the diameter and location of the vessels are uneven, the number of vessels is usually greater than in healthy tissues.

A bone x-ray should be performed in order to make an accurate diagnosis. In most cases, the use of a contrast agent allows you to get more accurate information and provide better care to the patient. However, it must be borne in mind that the use of contrast agents has some contraindications and limitations. The technique of using contrast agents requires time and experience from the radiologist.

X-ray and computed tomography ( CT) bones

Computed tomography is an X-ray method that has increased accuracy and information content. To date, computed tomography is the best method for examining the skeletal system. With CT, you can get a three-dimensional image of any bone in the body or sections through any bone in all possible projections. The method is accurate, but at the same time creates a high radiation load.

The advantages of CT over standard radiography are:

high resolution and accuracy of the method;
the possibility of obtaining any projection, while X-rays are usually carried out in no more than 2 - 3 projections;
the possibility of three-dimensional reconstruction of the studied part of the body;
lack of distortion, compliance with linear dimensions;
the possibility of simultaneous examination of bones, soft tissues and blood vessels;
Possibility of real-time survey.

Computed tomography is performed in cases where it is necessary to diagnose such complex diseases as osteochondrosis, intervertebral hernia, tumor diseases. In cases where the diagnosis is not particularly difficult, a conventional x-ray is performed. It is necessary to take into account the high radiation exposure of this method, which is why CT is not recommended to be performed more often than once a year.

X-ray of bones and magnetic resonance imaging ( MRI)

Magnetic resonance imaging ( MRI) is a relatively new diagnostic method. MRI allows you to get an accurate image of the internal structures of the body in all possible planes. With the help of computer simulation tools, MRI makes it possible to perform a three-dimensional reconstruction of human organs and tissues. The main advantage of MRI is the complete absence of radiation exposure.

The principle of operation of a magnetic resonance tomograph is to impart a magnetic impulse to the atoms that make up the human body. After that, the energy released by the atoms when returning to their original state is read. One of the limitations of this method is the impossibility of using in the presence of metal implants, pacemakers in the body.

MRI usually measures the energy of hydrogen atoms. Hydrogen in the human body is found most often in the composition of water compounds. Bone contains much less water than other tissues in the body, so MRI is less accurate when examining bones than it is when examining other areas of the body. In this, MRI is inferior to CT, but still exceeds conventional radiography in accuracy.

MRI is the best method for diagnosing bone tumors, as well as metastases of bone tumors in distant areas. One of the serious disadvantages of this method is the high cost and time spent on research ( 30 minutes or more). All this time, the patient must take a stationary position in the magnetic resonance tomograph. This device looks like a tunnel of a closed structure, which causes discomfort for some people.

X-ray and bone densitometry

The study of the structure of bone tissue is carried out in a number of diseases, as well as in the aging of the body. Most often, the study of bone structure is carried out with a disease such as osteoporosis. A decrease in the mineral content of the bones leads to their fragility, the risk of fractures, deformations and damage to neighboring structures.

An X-ray image allows you to evaluate the structure of the bones only subjectively. To determine the quantitative parameters of bone density, the content of minerals in it, densitometry is used. The procedure is fast and painless. While the patient lies motionless on the couch, the doctor examines certain parts of the skeleton using a special sensor. The most important are the data of densitometry of the femoral head and vertebrae.

There are the following types of bone densitometry:

quantitative ultrasound densitometry;
x-ray absorptiometry;
quantitative magnetic resonance imaging;
quantitative computed tomography.

X-ray type densitometry is based on the measurement of X-ray absorption by bone. If the bone is dense, then it delays most of the x-ray radiation. This method is very accurate, but has an ionizing effect. Alternative methods of densitometry ( ultrasonic densitometry) are safer, but also less accurate.

Densitometry is indicated in the following cases:

osteoporosis;
mature age ( over 40 - 50 years old);
menopause in women;
frequent bone fractures;
spinal diseases ( osteochondrosis, scoliosis);
any bone damage
sedentary lifestyle ( hypodynamia).

Indications and contraindications for X-ray of the bones of the skeleton

X-ray of the bones of the skeleton has an extensive list of indications. Different diseases can be characteristic of different ages, but injuries or tumors of the bones can occur at any age. For the diagnosis of diseases of the skeletal system, X-ray is the most informative method. The X-ray method also has some contraindications, which, however, are relative. However, be aware that bone x-rays can be dangerous and harmful if used too frequently.

Indications for bone x-ray

X-ray examination is an extremely common and informative study for the bones of the skeleton. Bones are not available for direct examination, but an x-ray can provide almost all the necessary information about the condition of the bones, their shape, size and structure. However, due to the release of ionizing radiation, an X-ray of the bones cannot be performed too often and for any reason. Indications for bone x-rays are determined quite accurately and are based on the complaints and symptoms of patients' diseases.

X-ray of bones is indicated in the following cases:

traumatic injuries of bones with severe pain syndrome, deformation of soft tissues and bones;
dislocations and other damage to the joints;
anomalies in the development of bones in children;
growth lag in children;
limited mobility in the joints;
pain at rest or with movement of any part of the body;
an increase in bone volume, if a tumor is suspected;
preparation for surgical treatment;
assessment of the quality of the treatment ( fractures, transplants, etc.).

The list of skeletal diseases that are detected using x-rays is very extensive. This is due to the fact that diseases of the skeletal system are usually asymptomatic and are detected only after an X-ray examination. Some diseases, such as osteoporosis, are age-related and almost inevitable as the body ages.

X-ray of the bones in most cases allows differentiation between the listed diseases, due to the fact that each of them has reliable radiological signs. In difficult cases, especially before surgical operations, the use of computed tomography is indicated. Doctors prefer to use this study, as it is the most informative and has the least amount of distortion compared to the anatomical dimensions of the bones.

Contraindications for x-ray examination

Contraindications to X-ray examination are associated with the presence of an ionizing effect in X-rays. At the same time, all contraindications to the study are relative, since they can be neglected in emergency cases, such as fractures of the bones of the skeleton. However, if possible, the number of X-ray studies should be limited and not carried out unnecessarily.

Relative contraindications for X-ray examination include:

the presence of metal implants in the body;
acute or chronic mental illness;
severe condition of the patient massive blood loss, unconsciousness, pneumothorax);
first trimester of pregnancy;
childhood ( under 18).

X-ray with the use of contrast agents is contraindicated in the following cases:

allergic reactions to components of contrast agents;
endocrine disorders ( thyroid disease);
severe liver and kidney disease;

Due to the fact that the radiation dose in modern X-ray units is reduced, the X-ray method is becoming safer and allows removing restrictions on its use. In the case of complex injuries, x-rays are taken almost immediately in order to start treatment as soon as possible.

Irradiation doses for various methods of X-ray examination

Modern radiation diagnostics adheres to strict safety standards. X-ray radiation is measured with the help of special dosimeters, and X-ray installations undergo special certification for compliance with radiological exposure standards. Irradiation doses are not the same for different research methods, as well as for different anatomical regions. The unit of radiation dose is milliSievert ( mSv).

Irradiation doses for various bone x-ray methods

As can be seen from the data presented, computed tomography bears the greatest X-ray load. At the same time, computed tomography is the most informative method of examining bones today. It can also be concluded that digital radiography has a great advantage over film radiography, since the X-ray load is reduced by 5 to 10 times.

How often can an x-ray be taken?

X-ray radiation carries a certain danger to the human body. It is for this reason that all radiation that was received for medical purposes should be reflected in the patient's medical record. Such records should be maintained in order to comply with annual norms that limit the possible number of X-ray examinations. Thanks to the use of digital radiography, their number is sufficient to solve almost any medical problem.

The annual ionizing radiation that the human body receives from the environment ( natural background), ranges from 1 to 2 mSv. The maximum allowable dose of X-ray radiation is 5 mSv per year or 1 mSv for each of 5 years. In most cases, these values are not exceeded, since the radiation dose in a single study is several times less.

The number of X-ray examinations that can be performed during the year depends on the type of examination and the anatomical area. On average, 1 CT scan or 10 to 20 digital radiographs is allowed. However, there are no reliable data on the impact of radiation doses of 10-20 mSv annually. We can only say with certainty that to some extent they increase the risk of certain mutations and cellular disorders.

What organs and tissues suffer from ionizing radiation from x-ray machines?

The ability to cause ionization is one of the properties of X-rays. Ionizing radiation can lead to spontaneous decay of atoms, cellular mutations, failure in cell reproduction. That is why X-ray examination, which is a source of ionizing radiation, requires rationing and setting threshold values of radiation doses.

Ionizing radiation has the greatest effect on the following organs and tissues:

bone marrow, hematopoietic organs;
lens of the eye;
endocrine glands;
genitals;
skin and mucous membranes;
the fetus of a pregnant woman;
all organs of the child's body.

Ionizing radiation at a dose of 1000 mSv causes the phenomenon of acute radiation sickness. This dose enters the body only in case of catastrophes ( atomic bomb explosion). In smaller doses, ionizing radiation can lead to premature aging, malignant tumors, and cataracts. Despite the fact that the dose of X-ray radiation has significantly decreased today, there are a large number of carcinogenic and mutagenic factors in the outside world, which together can cause such negative consequences.

Is it possible to do bone x-rays for pregnant and lactating mothers?

Any x-ray examination is not recommended for pregnant women. According to the World Health Organization, a dose of 100 mSv almost inevitably causes fetal abnormalities or mutations leading to cancer. The first trimester of pregnancy is of the greatest importance, since during this period the most active development of fetal tissues and the formation of organs occurs. If necessary, all x-ray studies are transferred to the second and third trimester of pregnancy. Human studies have shown that x-rays taken after the 25th week of pregnancy do not lead to abnormalities in the baby.

For nursing mothers, there are no restrictions in performing x-rays, since the ionizing effect does not affect the composition of breast milk. Full-fledged studies in this area have not been conducted, therefore, in any case, doctors recommend that nursing mothers express the first portion of milk while breastfeeding. This will help to play it safe and maintain confidence in the health of the child.

X-ray examination of bones for children

X-ray examination for children is considered undesirable, since it is in childhood that the body is most susceptible to the negative effects of ionizing radiation. It should be noted that it is in childhood that the greatest number of injuries occur, which lead to the need to perform an X-ray examination. That is why X-rays are performed for children, but various protective devices are used to protect developing organs from radiation.

An X-ray examination is also required for growth retardation in children. In this case, x-rays are taken as many times as required, since the treatment plan includes x-rays after a certain period of time ( usually 6 months). Rickets, congenital skeletal anomalies, tumors and tumor-like diseases - all these diseases require radiation diagnostics and cannot be replaced by other methods.

Preparing for a bone x-ray

Study preparation is at the heart of any successful study. Both the quality of diagnosis and the result of treatment depend on this. Preparing for an x-ray examination is a fairly simple event and usually does not create difficulties. Only in some cases, such as x-rays of the pelvis or spine, do x-rays require special preparation.

There are some features of preparing children for x-rays. Parents should help doctors and properly psychologically prepare children for the study. It is difficult for children to remain motionless for a long time, they are also often afraid of doctors, people in white coats. Thanks to the cooperation between parents and doctors, it is possible to achieve good diagnosis and high-quality treatment of childhood diseases.

How to get a referral for a bone x-ray? Where is X-ray performed?

Bone X-rays can be performed today at almost any center that provides medical care. Despite the fact that today X-ray equipment is widely available, X-ray examinations are performed only with the direction of a doctor. This is due to the fact that x-rays to a certain extent harm human health and have some contraindications.

X-ray of the bones is performed in the direction of doctors of different specialties. Most often, it is performed urgently when providing first aid in trauma departments, emergency hospitals. In this case, the referral is issued by the on-duty traumatologist, orthopedist or surgeon. X-rays of bones may also be performed at the direction of family physicians, dentists, endocrinologists, oncologists, and other physicians.

An x-ray of the bones is performed in various medical centers, clinics, and hospitals. To do this, they are equipped with special X-ray rooms, which have everything necessary for this kind of research. X-ray diagnostics are carried out by radiologists with special knowledge in this field.

What does an X-ray room look like? What is in it?

An x-ray room is a place where x-rays of various parts of the human body are taken. The X-ray room must meet high standards of radiation protection. In the decoration of walls, windows and doors, special materials are used that have a lead equivalent, which characterizes their ability to trap ionizing radiation. In addition, it has dosimeters-radiometers and personal radiation protection equipment, such as aprons, collars, gloves, skirts and other items.

The X-ray room should have good lighting, primarily artificial, since the windows are small and natural light is not enough for high-quality work. The main equipment of the office is an X-ray unit. X-ray machines come in a variety of forms as they are designed for different purposes. All types of X-ray units are present in large medical centers, but the simultaneous operation of several of them is prohibited.

In a modern X-ray room there are the following types of X-ray units:

stationary x-ray machine allows you to perform radiography, fluoroscopy, linear tomography);
ward mobile x-ray unit;
orthopantomograph ( X-ray machine for jaws and teeth);
digital radiovisiograph.

In addition to X-ray units, the office has a large number of auxiliary tools and equipment. It also includes equipment for the workplace of a radiologist and laboratory assistant, tools for obtaining and processing x-rays.

Additional equipment for X-ray rooms includes:

a computer for processing and storing digital images;
film processing equipment;
film drying cabinets;
Consumables ( film, photoreagents);
negatoscopes ( bright screens for viewing pictures);
tables and chairs;
filing cabinets;
bactericidal lamps ( quartz) for disinfection of premises.

Preparing for a bone x-ray

The tissues of the human body, which differ in different density and chemical composition, absorb X-rays in different ways and, due to this, have a characteristic X-ray image. The bones have a high density and very good natural contrast, so most bones can be x-rayed without much preparation.

If a person is to have an x-ray examination of most of the bones, then it is enough to come to the x-ray room on time. At the same time, there are no restrictions on food intake, liquids, smoking before an X-ray examination. It is recommended that you do not bring any metal items with you, especially jewelry, as these will need to be removed prior to the examination. Any metal objects interfere with the x-ray.

The process of obtaining an X-ray image does not take much time. However, in order for the picture to turn out to be of high quality, it is very important for the patient to remain still during its execution. This is especially true for young children who are restless. X-rays for children are carried out in the presence of parents. For children less than 2 years old, X-rays are performed in the prone position, it is possible to use special fixation, which fixes the position of the child on the X-ray table.

One of the serious advantages of x-rays is the possibility of its use in emergency cases ( injuries, falls, traffic accidents) without any preparation. There is no loss in image quality. If the patient is not transportable or is in serious condition, then it is possible to perform an X-ray directly in the ward where the patient is located.

Preparation for X-ray of the pelvic bones, lumbar and sacral spine

An x-ray of the pelvic bones, lumbar and sacral spine is one of the few types of x-rays that requires special preparation. It is explained by anatomical proximity with the intestines. Intestinal gases reduce the sharpness and contrast of the x-ray, which is why special preparations are made to cleanse the intestines before this procedure.

Preparation for x-ray of the pelvis and lumbar spine includes the following main elements:

bowel cleansing with laxatives and enemas;
following a diet that reduces the formation of gases in the intestines;
conducting research on an empty stomach.

The diet should begin 2 to 3 days before the study. It excludes flour products, cabbage, onions, legumes, fatty meats and dairy products. In addition, it is recommended to take enzyme preparations ( pancreatin) and activated charcoal after meals. On the day before the examination, an enema is given or drugs such as Fortrans are taken, which help to cleanse the intestines in a natural way. The last meal should be 12 hours before the study, so that the intestines remain empty until the time of the study.

Bone X-Ray Techniques

X-ray examination is designed to examine all the bones of the skeleton. Naturally, for the study of most bones, there are special methods for obtaining x-rays. The principle of taking pictures in all cases remains the same. It involves placing the part of the body to be examined between the X-ray tube and the radiation receiver, so that the X-rays pass at right angles to the bone under examination and to the cassette with X-ray film or sensors.

The positions occupied by the components of the x-ray machine relative to the human body are called stacking. Over the years of practice, a large number of x-ray stacks have been developed. The quality of x-rays depends on the accuracy of their observance. Sometimes, in order to comply with these prescriptions, the patient has to take a forced position, but the X-ray examination is performed very quickly.

Laying usually involves taking pictures in two mutually perpendicular projections - front and side. Sometimes the study is supplemented by an oblique projection, which helps to get rid of the overlap of some parts of the skeleton on each other. In the event of a severe injury, some styling becomes impossible. In this case, an X-ray is performed in the position that causes the least discomfort to the patient and which will not lead to displacement of the fragments and aggravation of the injury.

Method for examining the bones of the limbs ( hands and feet)

X-ray examination of the tubular bones of the skeleton is the most frequent X-ray examination. These bones make up the bulk of the bones, the skeleton of the arms and legs is completely made up of tubular bones. The X-ray technique should be familiar to anyone who has received injuries to their arms or legs at least once in their lives. The study takes no more than 10 minutes, it does not cause pain or discomfort.

Tubular bones can be examined in two perpendicular projections. The main principle of any X-ray image is the location of the object under study between the emitter and the X-ray sensitive film. The only condition for a high-quality image is the immobility of the patient during the study.

Before the study, the limb section is exposed, all metal objects are removed from it, the study area is placed in the center of the cassette with x-ray film. The limb should “lie” freely on the film cassette. The X-ray beam is directed to the center of the cassette perpendicular to its plane. The picture is taken in such a way that adjacent joints are also included in the x-ray. Otherwise, it is difficult to distinguish between the upper and lower end of the tubular bone. In addition, the large coverage of the area helps to eliminate damage to the joints or adjacent bones.

Usually, each bone is examined in direct and lateral projection. Sometimes pictures are performed in conjunction with functional tests. They consist in flexion and extension of the joint or load on the limb. Sometimes, due to injury or the inability to change the position of the limb, it is necessary to use special projections. The main condition is to maintain the perpendicularity of the cassette and the X-ray emitter.

The technique of X-ray examination of the bones of the skull

X-ray examination of the skull is usually performed in two mutually perpendicular projections - lateral ( in profile) and direct ( full face). An x-ray of the skull bones is prescribed for head injuries, with endocrine disorders, for diagnosing deviations from indicators of age-related bone development in children.

X-ray of the bones of the skull in direct anterior projection provides general information about the condition of the bones and the connections between them. It can be performed in a standing or lying position. Usually the patient lies on the X-ray table on the stomach, a roller is placed under the forehead. The patient remains motionless for several minutes while the X-ray tube is directed to the occipital region and the picture is taken.

X-ray of the bones of the skull in a lateral projection is used to study the bones of the base of the skull, the bones of the nose, but is less informative for other bones of the facial skeleton. To perform an x-ray in a lateral projection, the patient is placed on the x-ray table on his back, the film cassette is placed on the left or right side of the patient's head parallel to the body axis. The X-ray tube is directed perpendicular to the cassette from the opposite side, 1 cm above the ear-pupillary line.

Sometimes doctors use an x-ray of the bones of the skull in the so-called axial projection. It corresponds to the vertical axis of the human body. This styling has a parietal and chin direction, depending on which side the X-ray tube is located on. It is informative for the study of the base of the skull, as well as some bones of the facial skeleton. Its advantage is that it avoids the many overlaps of bones that are characteristic of direct projection.

X-ray of the skull in axial projection consists of the following steps:

the patient takes off metal objects, outerwear;
the patient takes a horizontal position on the x-ray table, lying on his stomach;
the head is positioned in such a way that the chin protrudes as much as possible forward, and only the chin and the front surface of the neck touch the table;
under the chin is a cassette with x-ray film;
the x-ray tube is directed perpendicular to the plane of the table, to the region of the crown, the distance between the cassette and the tube should be 100 cm;
after that, a picture is taken with the chin direction of the x-ray tube in a standing position;
the patient throws his head back so that the top of the head touches the support platform, ( raised x-ray table), and the chin was as high as possible;
the x-ray tube is directed perpendicular to the anterior surface of the neck, the distance between the cassette and the x-ray tube is also 1 meter.

Methods of X-ray of the temporal bone according to Stanvers, according to Schüller, according to Mayer

The temporal bone is one of the main bones that form the skull. In the temporal bone there are a large number of formations to which muscles are attached, as well as holes and channels through which nerves pass. Due to the abundance of bone formations in the facial region, X-ray examination of the temporal bone is difficult. That is why a variety of styling has been proposed to obtain special X-ray images of the temporal bone.

Currently, three projections of X-ray examination of the temporal bone are used:

Mayer technique ( axial projection). It is used to study the state of the middle ear, the pyramid of the temporal bone and the mastoid process. Mayer X-ray is performed in the supine position. The head is turned at an angle of 45 degrees to the horizontal plane, a cassette with x-ray film is placed under the ear under study. The X-ray tube is directed through the frontal bone of the opposite side, it should be directed exactly to the center of the external auditory opening of the side under study.
Method according to Schüller ( oblique projection). With this projection, the state of the temporomandibular joint, mastoid process, as well as the pyramid of the temporal bone is assessed. X-ray is performed lying on your side. The patient's head is turned to the side, and a cassette with X-ray film is placed between the ear of the examined side and the couch. The X-ray tube is located at a slight angle to the vertical and directed towards the foot end of the table. The X-ray tube is centered on the auricle of the examined side.
Method according to Stanvers ( transverse projection). A picture in a transverse projection allows you to assess the condition of the inner ear, as well as the pyramid of the temporal bone. The patient lies on his stomach, his head is turned at an angle of 45 degrees to the line of symmetry of the body. The cassette is placed in a transverse position, the X-ray tube is beveled at an angle to the head end of the table, the beam is directed to the center of the cassette. For all three techniques, an X-ray tube in a narrow tube is used.

Various x-ray techniques are used to study specific formations of the temporal bone. In order to determine the need for one or another type of styling, doctors are guided by the patient's complaints and the data of an objective examination. Currently, computed tomography of the temporal bone serves as an alternative to various types of X-ray stacking.

X-ray laying of the zygomatic bones in a tangential projection

To examine the zygomatic bone, the so-called tangential projection is used. It is characterized by the fact that X-rays propagate tangentially ( tangentially) in relation to the edge of the zygomatic bone. This styling is used to identify fractures of the zygomatic bone, the outer edge of the orbit, the maxillary sinus.

The X-ray technique of the zygomatic bone includes the following steps:

the patient takes off his outer clothing, jewelry, metal prostheses;
the patient takes a horizontal position on the stomach on the x-ray table;
the patient's head is rotated at an angle of 60 degrees and placed on a cassette containing x-ray film measuring 13 x 18 cm;
the side of the face being examined is on top, the x-ray tube is located strictly vertically, however, due to the tilt of the head, x-rays pass tangentially to the surface of the zygomatic bone;
during the study, 2 - 3 shots are taken with slight turns of the head.

Depending on the task of the study, the angle of rotation of the head can vary within 20 degrees. The focal length between the tube and the cassette is 60 centimeters. An x-ray of the zygomatic bone can be supplemented with an overview image of the bones of the skull, since all formations examined in a tangential projection are quite clearly visible on it.

Method of X-ray examination of the pelvic bones. Projections in which an x-ray of the pelvic bones is performed

X-ray of the pelvis is the main study for injuries, tumors, and other diseases of the bones of this area. An x-ray of the pelvic bones takes no more than 10 minutes, but there is a wide variety of methods for this study. The most common x-ray of the pelvic bones is performed in the posterior projection.

The sequence of performing a survey x-ray of the pelvic bones in the posterior projection includes the following steps:

the patient enters the X-ray room, removes metal jewelry and clothing, except for underwear;
the patient lies on the x-ray table on his back and maintains this position throughout the procedure;
arms should be crossed on the chest, and a roller is placed under the knees;
the legs should be slightly apart, the feet fixed in the established position with tape or sandbags;
the cassette with a film measuring 35 x 43 cm is located transversely;
the x-ray emitter is directed perpendicular to the cassette, between the upper anterior iliac crest and the pubic symphysis;
the minimum distance between the emitter and the film is one meter.

If the patient's limbs are damaged, then the legs are not given a special position, since this can lead to displacement of the fragments. Sometimes X-rays are taken to examine only one part of the pelvis, such as for injuries. In this case, the patient takes a position on the back, however, a slight rotation occurs in the pelvis, so that the healthy half is 3–5 cm higher. The intact leg is flexed and elevated, the thigh is vertical and out of range of the study. X-ray beams are directed perpendicular to the femoral neck and cassette. This projection gives a lateral view of the hip joint.

To study the sacroiliac joint, a posterior oblique projection is used. It is performed when the examined side is raised by 25 - 30 degrees. In this case, the cassette must be located strictly horizontally. The X-ray beam is directed perpendicular to the cassette, the distance from the beam to the anterior iliac spine is about 3 centimeters. When the patient is positioned in this way, the X-ray image clearly shows the connection between the sacrum and the ilium.

Determining the age of the skeleton by X-ray of the hand in children

Bone age accurately indicates the biological maturity of the body. Indicators of bone age are the points of ossification and fusion of individual parts of the bones ( synostoses). On the basis of bone age, it is possible to accurately determine the final growth of children, to establish a lag or advance in development. Bone age is determined by radiographs. After the radiographs were made in this way, the results obtained are compared with the standards according to special tables.

The most indicative in determining the age of the skeleton is the x-ray of the hand. The convenience of this anatomical region is explained by the fact that ossification points appear in the hand with a fairly high frequency, which allows regular examination and monitoring of growth rates. Bone age is mainly used to diagnose endocrine disorders such as growth hormone deficiency ( growth hormone).

Comparison of the age of the child and the appearance of ossification points on the x-ray of the hand

Ossification points

X-ray (transillumination). Method of visual study of the image on a luminous screen. Assumes the study of the patient in the dark. The radiologist preliminarily adapts to the darkness, the patient is placed behind the screen.

The image on the screen allows, first of all, to obtain information about the function of the organ under study - its mobility, relationship with neighboring organs, etc. The morphological features of the object under study during transillumination are not documented, the conclusion only on transillumination is largely subjective, depending on the qualifications of the radiologist.

The radiation exposure during transillumination is quite large, so it is carried out only according to strict clinical indications. It is forbidden to carry out a preventive examination by the method of transillumination. X-ray is used to study the organs of the chest, gastrointestinal tract, sometimes as a preliminary, “targeting” method for special studies of the heart, blood vessels, gallbladder, etc.

X-ray is used to study the organs of the chest, gastrointestinal tract, sometimes as a preliminary, “targeting” method for special studies of the heart, blood vessels, gallbladder, etc.

In recent decades, X-ray image intensifiers (Fig. 3.) - URI or image intensifier are becoming more widespread. These are special devices that make it possible to obtain a bright image of the object under study on the screen of a television monitor with a low radiation exposure of the patient using electro-optical conversion and amplification. Using URI, it is possible to carry out fluoroscopy without dark adaptation, in a non-darkened room, and, most importantly, the patient's radiation dose is sharply reduced.

Radiography. A method based on the illumination of a photographic emulsion containing silver halide particles with X-rays (Fig. 4.). Since the rays are absorbed by tissues differently, depending on the so-called "density" of the object, different areas of the film are exposed to different amounts of radiation energy. Hence the different photographic blackening of different points of the film, which is the basis for obtaining an image.

If neighboring areas of the object being photographed absorb rays differently, they speak of "radiological contrast".

After irradiation, the film must be developed, i.e. reduce the Ag+ ions formed as a result of exposure to radiation energy to Ag atoms. When developing the film darkens, the image appears. Since only a small fraction of the silver halide molecules are ionized during imaging, the remaining molecules must be removed from the emulsion. To do this, after development, the film is placed in a fixing solution of sodium hyposulfite. Halide silver under the influence of hyposulfite turns into a highly soluble salt absorbed by the fixing solution. The manifestation takes place in an alkaline environment, fixation - in an acidic one. After thorough washing, the image is dried and labelled.

Radiography is a method that allows you to document the state of the object being photographed at the moment. However, its disadvantages are high cost (the emulsion contains an extremely scarce precious metal), as well as difficulties that arise when studying the function of the organ under study. Irradiation of the patient during the picture is somewhat less than during transillumination.

In some cases, the X-ray contrast of neighboring tissues makes it possible to obtain their image in the pictures under normal conditions. If neighboring tissues absorb rays approximately equally, one has to resort to artificial contrasting. To do this, a contrast agent is introduced into the cavity, lumen of the organ or around it, which absorbs rays either much less (gaseous contrast agents: air, oxygen, etc.) or much more than the object under study. The latter include barium sulphate, used to study the gastrointestinal tract, and iodine preparations. In practice, oily solutions of iodine (iodolipol, mayodil, etc.) and water-soluble organic iodine compounds are used. Water-soluble contrast agents are synthesized based on the objectives of the study for contrasting the lumen of blood vessels (cardiotrast, urographin, verografin, omnipaque, etc.), bile ducts and gallbladder (bilitrast, iopognost, bilignost, etc.), urinary system (urographin, omnipaque, etc. ). Since free iodine ions may be formed when contrast agents dissolve, patients suffering from hypersensitivity to iodine ("iodism") cannot be examined. Therefore, in recent years, non-ionic contrast agents are more often used, which do not cause complications even when large amounts are administered (omnipack, ultravist).

Screening gratings are used to improve image quality in radiography, allowing only parallel rays to pass through.

About terminology. Usually use the term "roentgenogram of such and such an area." So, for example, “chest x-ray”, or “pelvis x-ray”, “right knee x-ray”, etc. Some authors recommend building the name of the study from the Latin name of the object with the addition of the words "-graphy", "-gram". So, for example, "craniogram", "arthrogram", "colonogram", etc. In cases where gaseous contrast agents are used, i. e. gas is injected into the lumen of the organ or around it, the word “pneumo-” is added to the name of the study (“pneumoencephalography”, “pneumoarthrography”, etc.).

Fluorography. A method based on photographic capture of an image from a luminous screen in a special camera. It is used in mass preventive studies of the population, as well as for diagnostic purposes. The size of the fluorogram 7´7 cm, 10´10 cm allows you to get sufficient information about the state of the chest and other organs. Radiation exposure during fluorography is somewhat greater than with radiography, but less than with transillumination.

Tomography. In a conventional x-ray examination, the planar image of objects on a film or on a luminous screen is summarized due to the shadows of many points located closer and further from the film. So, for example, the image of the organs of the chest cavity in direct projection is the sum of the shadows related to the anterior chest, the anterior and posterior sections of the lungs, and the posterior sections of the chest. The lateral view is a composite image of both lungs, mediastinum, lateral sections of the right and left ribs, etc.

In some cases, such a summation of shadows does not allow a detailed assessment of the area of the object under study located at a certain depth, since its image is covered by shadows above and below (or anteriorly and posteriorly) located objects.

The way out of this is the technique of layer-by-layer research - tomography.

The essence of tomography is to use the effect of smearing all layers of the studied body part, except for one, which is being studied.

In a tomograph, an X-ray tube and a film cassette move in opposite directions during an image, so that the beam constantly passes only through some given layer, “smearing” the layers above and below. In this way, the entire thickness of the object can be studied sequentially.

The greater the angle of mutual rotation of the tube and the film, the thinner the layer that gives a clear image. In modern tomographs, this layer is about 0.5 cm.

In some cases, on the contrary, an image of a thicker layer is required. Then, by reducing the angle of rotation of the film and tube, so-called zonograms are obtained - tomograms of a thick layer.

Tomography is a very commonly used research method that provides valuable diagnostic information. Modern X-ray machines in all countries are produced with tomographic attachments, which allows them to be universally used both for transillumination and imaging, and for tomography.

CT scan. The development and implementation of computed tomography in the practice of clinical medicine is the greatest achievement of science and technology. A number of foreign scientists (E. Markotred and others) believe that since the discovery of X-rays in medicine, there has not been a more significant development than the creation of a computed tomograph.

CT allows you to study the position, shape and structure of various organs, as well as their relationship with neighboring organs and tissues. In the study, the image of the object is presented as a kind of cross section of the body at given levels.

CT is based on the creation of images of organs and tissues using a computer. Depending on the type of radiation used in the study, tomographs are divided into x-ray (axial), magnetic resonance, emission (radionuclide). Currently, X-ray (CT) and magnetic resonance (MRI) imaging studies are becoming more widespread.

For the first time, Oldendorf (1961) made a mathematical reconstruction of the transverse image of the skull using 131 iodine as a radiation source, Cormack (1963) developed a mathematical method for reconstructing a brain image with an X-ray image source. In 1972, Hounsfield built the first x-ray CT for the study of the skull in the English company EMU, and already in 1974 a CT was built for tomography of the whole body, and since that time, the increasing use of computer technology has led to the fact that CT, and in recent years and magnetic resonance therapy (MRI) became a common method of examining patients in large clinics.

Modern computer tomographs (CT) consist of the following parts:

1. Table for scanning with a conveyor for moving the patient in a horizontal position at the signal of the computer.

2. A ring-shaped support ("Gantry") with a radiation source, detector systems for collecting, amplifying the signal and transmitting information to a computer.

3. Installation control panel.

4. Computer for processing and storing information with a disk drive.

5. Television monitor, camera, tape recorder.

CT has several advantages over conventional x-rays, namely:

1. High sensitivity, which makes it possible to distinguish the image of neighboring tissues not within 10–20% of the difference in the degree of absorption of X-rays, which is necessary for conventional X-ray examination, but within 0.5–1%.

2. It makes it possible to study the tissue layer under study without the layering of “smeared” shadows above and below the underlying tissues, which is inevitable with conventional tomography.

3. Provides accurate quantitative information about the extent of the pathological focus and its relationship with neighboring tissues.

4. Allows you to get an image of the transverse layer of the object, which is impossible with conventional X-ray examination.

All this can be used not only to determine the pathological focus, but also for certain measures under the control of CT, for example, for diagnostic puncture, intravascular interventions, etc.

CT diagnostics is based on the ratio of density or adsorption values of neighboring tissues. Each tissue, depending on its density (based on the atomic mass of its constituent elements), absorbs, adsorbs x-rays differently. For each tissue, an appropriate adsorption coefficient (KA) was developed on a scale. The CA of water is taken as 0, the CA of the bones with the highest density is taken as +1000, and the CA of air is taken as -1000.

To enhance the contrast of the object under study with neighboring tissues, the "enhancement" technique is used, for which contrast agents are injected.

Radiation exposure during X-ray CT is commensurate with that in conventional X-ray examination, and its information content is many times higher. So, on modern tomographs, even with the maximum number of slices (up to 90), it is within the load during a conventional tomographic examination.