Radioactivity and life. YK Kudrytski (MD) 1971 Part 15.

determine the reaction threshold, which depends in this case, dlitslynyut I1 bleeding.
The first question that arises immediately when attempting to) l (1'1 '!> At least an approximate estimate of the total stated problem can be formulated as follows: Are there levels of radiation exposure, which would not cause any radiation reactions of the organism? The answer may only be 'one: no, not there! All the known facts to date confirm the validity of such a response. Some of. have already been given. A little further on you will learn about the biological effects of natural levels of ionizing radiation. Thus, the entire known range of levels of radiation exposure is biologically effective.
Consequently, the threshold response should express-Hsia in its qualitative change in the appearance of new forms of response of the body to increase the radiation exposure. Up-to-Menwith radiobiological data allow us to prove sushe.stvovanie threshold relationship.
So, after a single irradiation of the whole body dose of 10 (}: X-rays and more at mlekopitayuitsih arises, as we know, new, irradiated at lower doses are not developing a form of response - acute radiation sickness. Radiation exposure. 600 and more x-rays are incompatible with life . Therefore, these doses are said to be absolutely lethal. It is clear that this effect is also a new quality threshold. Finally, at doses of 15-20 thousand animals P _ killed at the time of exposure because of, the heavy, shokopodobnogo central nervous system. This death "a ray", of course, is also a special form of the response is qualitatively different..
As can be seen from the above examples, change the dose is changed qualitatively and form of the response of the organism. Similar relations hold when the temporal and spatial distribution of radiation. Indeed, a qualitatively different razvene form of response associated development 'of radiation sickness after a single irradiation dose of 150 r and the preservation of health when receiving the same dose for 30 years profeesionalnyh life? If we take the duration of a single irradiation for 1 min., The difference in temporal distribution of the dose will reach fifteen million times.
With respect to a threshold response of the organism at different spatial distribution of radiation exposure convincing example is the comparison of total body irradiation at a dose of 500 r, causing severe radiation sickness and exposure of the scalp with the same dose in order to achieve hair loss, so-called epilation. Rentgenoepilyatsiya used mainly in children with fungal diseases of the scalp and, of course, nevyzyvala development of radiation sickness.