Radiation Effects in Man, Animals and Plants

The effects of radiation on microrganisms, plants and animals differ appreciably. From Table 22.6, it is evident that organisms at a low stage of evolution exhibit much higher radiation resistance than those at a higher evolutionary stage. 

Dose of inactivation (Z)j) or 50% lethal dose within 30 days (2)50/30) 

Two kinds of radiation exposure are distinguished, stochastic exposure (the effects are distributed statistically over a large population), and deterministic exposure (the effects are inevitable or intended, as in the case of deliberate irradiation, e.g. in radiotherapy). 

The survivors of the bombs dropped over Japan in 1945 are the most important source of information about human whole-body irradiation. The health of about 76 000 persons who had been exposed to doses of up to 7-8 Gy of instantaneous neutron and y radiation and that of their children has been investigated in detail for 

For other types of cancer, the excess malignancies are relatively low. They appear usually after a latent period of about lOy, and their frequency increases with time. 

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