RADIO ISOTOPE DIAGNOSIS

From Big Medical Encyclopedia

RADIO ISOTOPE DIAGNOSIS (synonym: radionuclide diagnosis, isotope diagnosis) — recognition of pathological changes of separate bodies and systems by means of methods of a radio isotope research.

The river of is founded on registration and measurement of radiations from the radio pharmaceuticals (RFP) administered in an organism or radiometry biol. tests. The radio isotope research (see) with use of radioactive marked connections (see) reflects their movement and distribution in bodies and body tissues and does not influence the current fiziol, processes. By means of radio pharmaceuticals (see) it is possible to study a metabolism, function of bodies and systems, speed of the movement of blood, a lymph, exchange of gases, secretory and excretory processes, etc.

Special success is achieved in R. by by means of the research in vitro, a cut can be applied at the big contingent of persons as screening test to early detection of various diseases (see. Screening ). Further development of R. of is connected both with development new, and with improvement of the existing diagnostic methods of diseases of various bodies and systems by means of short-lived radio pharmaceuticals. Researches on development and receiving ultrashort-lived radio pharmaceuticals are conducted with 13 N, 15 O, 18 F, on replacement 131 I and its derivatives short-lived analog 123 J. In a wedge, practice implement transmission computer tomographs, new reagents are developed for R. by of in vitro.

These R.' comparison by to results of radiological and ultrasonic researches is of great importance.

Depending on the purposes and research problems allocate 6 main methods P. of: wedge, radiometry, radiography, radiometry of all body, scanning and stsintigrafiya, determination of radioactivity biol, tests, radio isotope research in vitro.

Wedge, radiometry (see) — it is intended for definition of concentration of RFP in bodies and body tissues; consists in radioactivity measurement for a certain time slice depending on biol, features of the studied body or a body part of the patient. Assessment of a functional condition of the studied body is carried out in relative sizes, i.e. percentage of the entered activity; e.g., definition of function of a thyroid gland (so-called intra thyroid exchange of iodine) is calculated as percent of accumulation 131 I or 99m Tc from all entered activity in 1,2,4 and 24 hours after introduction of RFP. To a wedge, radiometry also contact radiometry, intended for diagnosis of the tumors which are located on the surface of skin, eye, mucous membrane of a throat, gullet, stomach, uterus and other bodies belongs. Radioactivity measurement after introduction of RFP on the healthy body part struck and symmetric to it is carried out by means of the radiometer supplied with a set of scintillation or gas-discharge beta probes. Results of a research are estimated on exceeding of intensity of accumulation of RFP in patol, the center in comparison with a symmetric healthy body part.

Radiography — dynamic registration of accumulation, redistribution and removal from body of RFP; it is applied to a research quickly proceeding fiziol, processes, such as blood circulation, gas exchange, a regional blood stream, ventilation of the lungs, various functions of a liver, kidneys, etc. The radiography is made by means of radiometers which have several sensors. Right after introduction of RFP the device begins to register continuously in the form of curves the speed and a radiation intensity in the set body parts or body. On the basis of the analysis of curves it is possible to judge a functional condition of this or that body.

Radiometry (see) all body it is carried out by means of the special counter. The device has one or several scintillation sensors with the big «field of vision» allowing to register distribution and accumulation of natural and artificial radioactive materials in all body or in separate bodies. The method is intended for studying of exchange of proteins, vitamins, iron, functions went. - kish. a path, definition of extracellular water, and also for a research of natural radioactivity of an organism and its impurity radioactive decay products. Assessment of results of a research is based on definition of the period of semi-removal of RFP (during the studying of a metabolism) or absolute amount of radionuclide (at a research of natural radioactivity).

Scanning (see) and stsintigrafiya (see) are intended for obtaining the gamma and topographical image of the bodies or body parts which are selectively concentrating RFP. The received picture of distribution and accumulation of radionuclide allows to judge topography, a form and the sizes of the studied body, and also existence in it patol, the centers. The gamma and topographical research is conducted by means of skanografichesky installations or the gamma and scintillation camera. The modern gamma cameras supplied with the COMPUTER allow to carry out a dynamic stsintigrafiya of body, i.e. to receive a consecutive series of pictures in time with its image and to judge the nature of redistribution in it RFP, napr, the centers with raised (a «hot» node) or lowered (a «cold» node) accumulation of RFP. The dynamic stsintigrafiya is used also for studying of quickly proceeding processes (a scintiangiography of heart, lungs, kidneys, etc.).

Determination of radioactivity biol, tests is intended for studying of a functional condition of bodies, napr, a thyroid gland, measurement of volume of the circulating blood, life expectancy of erythrocytes, water content in fabrics, etc. The method is based on determination of absolute or relative radioactivity of urine, blood serum, saliva, etc. Radioactivity measurement is performed in so-called well counters. Assessment of the received results is based on the relation of sizes of radioactivity biol, tests and activity of the administered drug.

The radio isotope research in vitro — definition of concentration of hormones, antigens, enzymes and other biologically active agents in plasma and blood serum. At the same time radionuclides and marked connections do not enter into an organism, and all research is conducted in a test tube.

The river of is carried out in specially equipped radiological laboratories having rooms (storage) for receiving and storage of RFP, procedural for their preparation and introduction by the patient, offices for radiometry, radiography, scanning and a stsintigrafiya, determination of radioactivity biol. tests. Offices and procedural are equipped with the radio diagnostic equipment — beta and gamma radiometers, tsirkulograf, scanners, gamma cameras, automatic counters of tests, a set of dosimeters for the general and individual dosimetry (see. Radio isotope diagnostic units , Radiological protective processing equipment ).

Functions of an organism are the cornerstone of each diagnostic test fiziol, and biochemical. Therefore R. is based by of diseases on participation of radionuclides and marked connections in fiziol, processes. Besides, indifferent radionuclides at their introduction to a vascular bed can circulate together with blood and a lymph and to be late temporarily in certain bodies on the basis of what judge the speed and the direction of their distribution.

In R.'s gastroenterology of allows to investigate function, situation and the sizes of sialadens, a liver, a spleen, a pancreas, and also motive and vsasyvatelny function went. - kish. path. So, define various parties of functional activity of a liver by radio diagnostic methods (secretory and excretory, anti-toxic, proteolytic) and a condition of portal blood circulation. Scanning and a stsintigrafiya of a liver with colloid drugs 198 Au, 99m Tc and 113m Jn give an idea of a form, an arrangement, the size of body, and also of focal and diffusion changes in it at hron, hepatitis, cirrhosis, echinococcosis and malignant new growths. A dynamic stsintigrafiya with the Bengalese pink 131 I or RFP 99m Tc gives extensive information on a functional condition of gepatobiliarny system.

Stsintigrafiya of a pancreas with a radioactive colloid 198 Au or 99m Tc allows to receive images of body and to judge inflammatory and volume changes in it. By method of a dynamic stsintigrafiya of a stomach by means of marked 99mTc food study a state motor evakuatornoy functions went. - kish. path. Research of absorption of marked fats, proteins and polyneuramin 12 gives the chance to estimate a condition of function of absorption went. - kish. a path at hron, a gastroenteritis, a peptic ulcer of a stomach and a duodenum.

In R.'s hematology of plays a large role in definition of life expectancy of erythrocytes, recognition of pernicious anemia by means of polyneuramin 12 , marked 58 Co, and in studying of a condition of a spleen.

The river of in cardiology includes: a research of a hemodynamics by means of measurement of speed of the movement of radionuclide on vessels and cardial cavities, and studying of a condition of a myocardium (on the nature of distribution of RFP in healthy and affected areas of a myocardium). The research central (radio cardiography) and a peripheral (radiotsirkulografiya) hemodynamics by introduction to a circulatory bed of RFP allows to determine the minute volume of heart, i.e. amount of the blood which is thrown out by heart in 1 min. On the basis of this indicator calculate also other parameters: minute index, stroke output of heart, shock index. Besides, the radiotsirkulografiya reflects the speed of a blood-groove in a small and big circle of blood circulation. The radio cardiography is of also great importance in diagnosis of the inborn and acquired heart diseases. At a research of a hemodynamics by means of the gamma camera receive the dynamic image of heart and large vessels along with functional indicators (see. Angiography , radio isotope; Radiotsirkulografiya ).

Important data in diagnosis of a myocardial infarction can be obtained at a stsintigrafiya of a myocardium. Use triple to a myocardium, i.e. selectively collecting in it, radionuclides ( 201 Te, 137 Cs and 43 K) allows to receive the image of heart and to reveal in it patol, the centers, including sites of a necrosis. Other radionuclides, napr, pyrophosphate 99m Tc, tend to collect only in nekrotizirovanny tissue of a myocardium. Therefore consecutive use of this or that RFP group gives the chance not only to state existence, localization and prevalence of a myocardial infarction, but also to estimate efficiency of the carried-out treatment.

In R.'s neurology of use for recognition of tumors of a brain and their recurrence. Stsintigrafiya of a brain by means of a pertekhnet 99mTc not only allows to reveal a tumor, but also gives the chance to judge localization, prevalence and character of a new growth. Also diagnosis of defeats of ventricles and vessels of a brain, blockade of the vertebral channel is carried out.

The river of in nephrology plays an important role in assessment of function and an anatomotopografichesky condition of kidneys. The radio isotope renografiya (see Renografiya radio isotope) is the most physiologic test of assessment of canalicular secretion and glomerular filtering. Static and dynamic stsintigrafiya of kidneys with Neohydrinum 197 Hg gippurany 131 I give the chance not only to receive the image, but also to estimate secretory and excretory function of kidneys.

Special value has R. of in oncology. With the advent of the radionuclides which are selectively collecting in a tumor like citrate ( 67 Ga, 111 In). 75 Se-methionine and 75 Se-selenit, 99m Tc of a pyrophosphate, and also marked 111 In or 57 Co of Bleomycinum opened new opportunities of diagnosis of primary tumor and metastasises of malignant tumors of lungs, intestines, a pancreas, limf, systems, tumors of the head, neck, etc. These drugs, collecting in a tumor, considerably increase resolving power of a stsintigrafiya (small tumors, with a diameter up to 2 cm come to light), allow to estimate efficiency of treatment and to reveal a recurrence. Moreover, scintigraphic signs of bone metastasises for 3 — 12 months advance emergence them rentgenol. symptoms.

In pulmonology determine by methods P. of function of external respiration and a regional blood stream. Stsintigrafiya of lungs received by means of macrounits of albumine, marked 131 J or 99m Tc entered into a venous bed gives the chance not only to receive the image of pulmonary fields, but also to estimate a condition of a pulmonary blood-groove. An inhalation stsintigrafiya by means of inert gas 133 Xe or aerosol of albumine, marked 99m Tc, is a sensitive method of assessment of ventilating function of lungs.

In R.'s endocrinology of apply to studying of diseases of a thyroid gland and disturbance of iodic exchange, definition of concentration of hormones of a hypophysis, thyroid and epithelial bodies, a pancreas and adrenal glands in blood serum. The research of intra thyroid and extra thyroid exchange of iodine and a stsintigrafiya of a thyroid gland are considered one of important tests in diagnosis of a hyperthyroidism and hypothyroidism and cancer of a thyroid gland.

Separate methods of radio isotope diagnosis — see articles devoted to these methods, e.g. Gepatografiya , Sialografiya , Holangiografiya , Encephalography etc., and also articles devoted to bodies and separate fiziol, to processes, e.g. Nitrogen metabolism , Water salt metabolism , Brain , Liver etc.



Bibliography: Agranat V. 3. Radio isotope diagnosis of malignant tumors, M., 1967, bibliogr.; Bogolyubov V. M. Radio isotope diagnosis of heart diseases and lungs, M., 1975, bibliogr.; Gabuniya R. I. A method of radiometry of all body in clinical diagnosis, M., 1975, bibliogr.; Zedgenidze G. A. and Zubovsky G. A. Clinical radio isotope diagnosis, M., 1968, bibliogr.; Zubovsky G. A. Gammastsintigra-fiya, M., 1978, bibliogr.; And sh m at x and - m e t about in A. I. Radio isotope diagnosis of diseases of the digestive system, M., 1979; Lindenbraten JI. And J1 I with with F. M. Medical radiology, M., 1979; Use of radioactive nuclides in clinical trials, under the editorship of R. I. Gabuniya, M., 1979, bibliogr.; Baum Sh. and. lake of Atlas of nuc-lear medicine imaging, N. Y., 1981; Handbuch der medizinischen Radiologie, hrsg. v. O. Olsson u. a., Bd 15, T. 2, B. u. a.,

1978.

P. I. Gabuniya.

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