Natural and radiation carcinogenesis in man III. Radiation carcinogenesis

Abstract

The application of the author’s hypothesis of spontaneous carcinogenesis to the phenom enon of radiation carcinogenesis is described. Equations connecting the carcinogenic response to acute and chronic irradiations are derived. The effects in genetic-carriers and in noncarriers require separate consideration and further distinction is necessary between the ' short'-and 'long’-term responses. It is shown that the cytotoxic effects of ionizing radiation have to be allowed for when the short-term response to an acute irradiation is assessed, although they may generally be ignored when estimating the long-term response. However, the long-term response in a carrier subpopulation will be complicated by the magnitude of the short-term effect. The influence of age is discussed and is shown to be complicated, especially in genetic carriers. The more reliable data for radiation carcinogenesis and leukaem ogenesis in manare used in conjunction with the hypothesis to calculate α/ m s— the ratio of the radiogenic to the spontaneous mutation coefficient. The values that emerge are reasonably consistent with one another and with the independent experimental evidence relating to the radiom utability of genes in germ and somatic cells of mice.