Radiation carcinogenesis—Laboratory studies

A brief review of animal studies following external radiation suggested the following generalizations. For low LET radiation several different dose-response relationships were obtained over a wide range of doses; lengthening the time over which the radiation is given generally lowers the risk of tumor induction. For high LET radiation the dose-response relationship usually appears to be linear and lengthening the time over which the radiation is spread does not lower the risk of tumor induction. No single RBE value for high LET radiation for tumor induction can be given but current studies point in the direction of an inverse relationship between RBE value and dose. Animal studies of radiation carcinogenesis provide information of more qualitative than quantitative significance in regard to human radiation carcinogenesis.