BETA DIAGNOSIS — the tracer technique of diagnosis based on studying of dynamics of accumulation in bodies and fabrics and removal from them of the beta radiating radioisotopes or their connections.
Most in clinic the method B. - of malignant tumors with use of disubstituted sodium phosphate, marked radioisotope of phosphorus was widely used — 32 P (half-life — 14,5 days, mean energy of beta radiation — 0,7 Mev).
The method is based on features of phosphoric exchange in fast-growing fabrics, and in particular in malignant tumors.
In the growing cells, and also in cells of malignant tumors there is a continuous protein synthesis and nucleoproteids, implementation to-rogo requires a significant amount of plastic material and energy. High mitotic and metabolic activity of the growing tumor demands, on the one hand, the increased formation of the energy-rich bonds rich with phosphates, and with another — strengthenings of processes of oxidizing phosphorylation and glycolysis. All this leads to the inclusion of the radioactive phosphorus entered into an organism, into cells of malignant tumors increased in comparison with similar normal fabric.
Level of radioactivity of phosphorus in the center of defeat is registered generally in two ways: beta radiometry by means of special diagnostic beta probes (fig.) and intravital photoballoon autoradiography (see).
In a habit view the technique of beta radio - metrii consists of administration of radioactive drug, radiometric inspection of the patient and interpretation of the received results.
32 R is the pure beta emitter (the maximum run of beta particles in fabrics — 8 mm) therefore the method of beta radiometry is used at a possibility of approach of a sensitive part of the diagnostic beta probe to the surface of tumoral education, napr, at diagnosis of malignant melanomas and a carcinoma cutaneum, throat cancer, a neck and a body of the womb, a rectum, a gullet, and also for definition of location of a tumor of a brain and for diagnosis of bronchopulmonary cancer during operation. At a superficial arrangement of tumors (5 mm from the surface of skin are not deeper) the method of beta radiometry can be used in diagnosis of a breast cancer, prostate cancer, new growths of an eye.
A radiotracer — disubstituted sodium phosphate, marked 32 R — it is possible to enter inside (at the rate of 1,0 — 1,5 mkkyuri/kg) or parenterally: intravenously (isotonic solution at the rate of 0,5 — 0,7 mkkyuri/kg), and also subcutaneously or intramusculary. At the researches conducted for the purpose of definition of location of a tumor of a brain and also in diagnosis of malignant new growths of an eye the entered activities of a radiotracer increase.
Radiometric inspection of the patient is made, as a rule, is triple: in 24, 48 and 72 hours after introduction to an organism of the patient of radioactive drug. Once the radiometry is carried out at researches during operation, and also at its combination to endoscopic diagnostic methods (a bronkhoradiometriya, an ezofagoradiometriya).
The net result of a research is expressed as a percentage, reflecting the relative level of accumulation 32 P in the center of defeat in comparison with the level of radioactivity in the site of similar normal fabric symmetric to it. Clinical assessment. results of beta radiometry by most of authors it is made on the level and dynamics of relative accumulation 32 P in the center of defeat. The high level of accumulation is characteristic of malignant new growths 32 P and stable dynamics of absorption of isotope; for benign tumors — low level of accumulation at stable dynamics of absorption. The high level of radioactivity in the center of defeat in the first days after introduction of the indicator with decrease in the subsequent terms of a research is characteristic of inflammatory processes.
Diagnostic efficiency of beta radiometry varies depending on localization of a new growth and, according to various authors, fluctuates from 70 to 90%.
Intravital photoballoon autoradiography it is used generally in diagnosis of cancer of gullet, stomach and rectum. For this purpose in 48 — 96 hours after introduction to an organism of the patient of a radiotracer and the corresponding training of the patient to it enter the cylinder covered with a special photoemulsion. In the course of the research the photocylinder is inflated by air (displacement volume) for ensuring contact of a photosensitive film with a mucosal surface of a cover of the studied bodies. After the corresponding exposure, removal of a cylinder from a cavity and the subsequent special photochemical processing of a photocylinder enter air into it, then the visual estimate of the autoradiogramm taking into account topography and extent of blackening of a photoemulsion layer of a cylinder is made.
Efficiency of a photoballoon autoradiography in diagnosis of cancer of gullet and stomach in general at all stages of a disease makes 86 — 73% respectively, however this way is most productive at diagnosis of cancer defeat in the I—II stages.
By means of B. - can obtain information on the relative level of phosphoric exchange in a tumor. This information can be used not only with tselyo diagnoses of malignant new growths, but also for definition biol, features of primary tumor and assessment of reaction of a tumor to antineoplastic influence (radiation therapy, himio-, hormonal therapy).
Bibliography: Agranat V. 3. Radio isotope diagnosis of malignant tumors, M., 1967, bibliogr.; Carefully in I. P. Radio isotope diagnosis of cancer of digestive tract, Minsk, 1973, bibliogr.; Oak E. D. and Leshchinsky A. F. Radio phosphoric diagnosis in oncology, Kiev, 1968, bibliogr.; Shchslokova S. V. Radio phosphoric diagnosis in Loronkologiya, page 20, etc., M., 1971, bibliogr.; D i e t-h e 1 m L. u. a. Erweiterung der Di-agnostik des Mammakarzinoms mit Hilfe von Isotopen, Strahlentherapie, Bd 131, S. 69, 1966.
B. 3. Agranat.