Biological Effects of Pulse X-rays

摘要

Time sequence on the biological effects of X-rays was reviewed with respect to cell death. When cells were exposed to X-rays, interaction between X-rays and biological materials in cell begins with physical processes (10~-18-10~-12 sec), followed by chemical (10~12-1 sec) and biological processes (1 sec-). The use of pulse X-rays will reveal the dependence of biological response on the dose rate of X-rays. In biological processes, cell death was modified by biological repair functions at the dose rates from 0.095 Gy/hr to 7 Gy/min. Above this dose-rate range, no significant change in the nature of the survival curve has been reported to the dose-rate up to 10~9 Gy/sec. Direct and indirect actions of X-rays are known in biological effects of X-rays. Detailed study of these processes using chemical scavengers showed that more than 90