blow to draw attention to the meaning of the term "legal limit" (RC) of ionizing radiation. This is such a limit of radiation exposure, which still does not cause irreversible changes in health. At present, the sanitary regulations of the maximum permissible dose for persons subject to the nature of their work exposure to radiation, p is equal to 5 per year. With more or less significant excess of maximum permissible level of adaptive possibilities of the body are insufficient. As a result of their limited develop pathological conditions. In this range of radiation effects is dose level, which is called the level or dose of risk. As the dose of risk in a single irradiation of the whole organism is considered to be 25 rubles. As a result of such doses appear abnormal, it is compatible with life. Finally, radiation exposure in excess of a single irradiation with 100 r, can cause severe mammalian disease process - radiation sickness. K. In this category include changes and a variety of radiation injuries resulting from local irradiation in large doses. For example, in radiation therapy of malignant tumors in order to achieve a cessation of tumor growth and its destruction, the patient is given a large dose, as measured by thousands of X-rays. In the tissue surrounding the tumor, and in the irradiated area of skin may develop radiation. of defeat. The risk of severe radiation have limited treatment options Agen radiotherapy. To a large extent the art of the doctor-radiotherapist is the ability to prevent their development. This category should include changes in the radial and the so-called long-term effects of radiation effects, developing over time, sometimes many years after exposure. Among them are the most dangerous cancers that occur frequently in 5-10 years or more after exposure. No less severe genetic mutations, inherited the descendants of irradiated as well as such late effects such as reduction, long-lasting • measured by life expectancy, early aging, decreased resistance to adverse effects, including infectious. All of these pathological processes, assigned to the latter category of radial changes are the result of large radial voadeystvy, A characteristic feature of the described biological effect depending on the magnitude of radiation exposure, commonly referred to as "the dose - effect" is, as already noted. ochenv wide dose range. Maximum level at 20-50 times higher than natural