Radiation hygienic evaluation of nuclear fission products (review).

Nuclear-fission products (NFP) are a complex mixture of radionuclides of variable organotropism. Their physicochemical properties depend on the conditions of their formation and age. In a contaminated environment they are a source of external, contact, and internal gamma- and beta-irradiation. Dangerous is the entry of NFP into the organism, especially that of children and pregnant women. In a radiation-hygiene review, the author sums up his own materials and those of other investigators on radiation injuries developing upon the contamination of the skin and penetration of NFP into the organism. The risk of injuries and delayed effects is evaluated. Dose sizes producing injuries of different severity are given. Protective measures should be directed toward prevention of skin contamination and entry of NFP into the organism, early sanitary treatment, and prompt discharge of radionuclides from the organism. Of particular importance in the genesis of severe injury, the course of reparative processes and formation of delayed pathology, is radiation injury to the thyroid gland by iodine radioisotopes. Hence an important place among prophylactic measures should belong to the "protection" of the thyroid gland and normalization of its function.