From Big Medical Encyclopedia

INCORPORATION OF RADIOACTIVE MATERIALS (Latin incorporatio inclusion) — penetration of radioactive materials into an organism.

Incorporation of natural radioactive materials (see), contained in small amounts in food stuffs, water and air, occurs constantly through respiratory tracts, went. - kish. path and skin. Besides, radioactive materials get to an organism in the form of the marked connections which are widely used in medicine for diagnosis and treatment of various diseases (see. Isotopes, radioactive ), and also in the course of work with radionuclides. In these cases exact calculation of doses, strict observance of the accident prevention, rules of personal hygiene and careful radiation control behind the content of radionuclides in air of production rooms and in an organism is necessary. At various emergencies, and also at tests nuclear weapon (see) pollution by radioactive materials of the environment is possible; joining in biol, circulation, they get into a human body. In case of military use of nuclear weapon the products of nuclear explosion infecting the area and air around explosion and on the way of the movement of a radioactive cloud can be a source of radioactive materials.

The incorporated radioactive materials are soaked up in an organism and carried on it by a blood flow. Absorbability of these substances depends from their physical. and chemical properties and fiziol, conditions of an organism. E.g., absorbability of radioactive aerosols is defined by the sizes of their particles: deeply get into easy particles of 0,5 in size — 2 microns; particles of the smaller sizes also easily get into lungs, but, without being late in them, are quickly removed with expired air; more coarse particles are late in upper respiratory tracts. Duration of a delay of radioactive materials in lungs is defined by their localization and solubility: from a nasopharynx, a trachea,

bronchial tubes, lungs aerosols quickly are removed thanks to activity of a ciliary epithelium; low solubility substances are slowly soaked up and consequently, and are late in an organism longer.

The nature of distribution of radioactive materials in an organism is various: are rather evenly distributed on bodies and fabrics an oxide of hyzone, 137 Cs, 134 Cs, 95 Nb, 106 Bu, other substances selectively collect or in a bone tissue — so-called osteotropny elements ( 140 Ba, 89 Sr, 90 Sr, 226 Ra), or in a bone tissue and a liver ( 144 Ce, 147 Pm, 239 Pu, 241 Am, 242 Cm, 252 Cf, 232 Th), or in a thyroid gland ( 125 I, 131 I, 211 At).

Radioactive materials are removed from an organism of hl. obr. through went. - kish. a path and kidneys, an insignificant part — through stalemate and sialadens. The substances which are badly soaking up in went. - kish. a path, are removed with excrements within 2 — 5 days after incorporation. Are quickly brought out of an organism 14 With, 3 H, 137 Cs, very slowly — 90 Sr, 144 Ce, 241 Am, 244 Cm, 239 Pu, 232 Th.

The incorporated radioactive materials, being exposed to radioactive decay, let out and - both beta particles and gamma radiation under the influence of which there is an internal radiation of an organism. Duration of such radiation is defined by effective half-life (see). At hit can develop in an organism of a large amount of radioactive materials radial illness (see); at the same time those bodies and fabrics in which radionuclide selectively collects preferential are surprised. So, at peroral hit and inhalation of badly soaking up radionuclides into the forefront pathology from outside acts went. - kish. path and lungs; osteotropny radionuclides cause damage of a bone tissue and marrow.

First aid at And. the river of century comes down to the prevention of further hit of radioactive materials in an organism and to their fastest removal.

Are applied to these purposes individual means of protection (see). Victims leave from a dangerous zone. The tubeless and probe gastric lavage, reception of adsorbents, salt laxatives, and also the means forming soluble complex compounds with radioactive materials (Unithiolum, Pentacinum, ethylene diamine tetraacetic to - that, etc.), drugs of calcium and ion-exchange means (citrate zirconium) is shown. Can be applied to the prevention of development of a radial illness radioprotectors (see).

Bibliography: Protection of the patient at radio isotope researches, the lane with English, M., 1974, bibliogr.; Standards of radiation safety (NRB-76), M., 1978; Osanov D. P. and Likhtarev I. A. Dosimetry of radiations of the incorporated radioactive materials, M., 1977, bibliogr.; The metabolism of compounds of plutonium and other actinides, Oxford, 1972.

Yu. I. Moskalyov.