The effect of dose fractionation on gamma-radiation induced mutations in mammalian cells

The lethal and mutagenic effects of single and fractionated doses of γ-radiation were studied in V79-4 Chinese hamster cells, as dose fractionation is of interest in radiation protection studies. The results show that the induction of 8-azaguanine resistant mutants has a non-linear dose-response curve following single doses of radiation. The lethal and mutagenic effects of fractionated doses were always less than if the radiation was given in a single dose. Any change in treatment which led to an increase in survival also led to a decrease in induced mutation frequency. There was a relationship between mutation and survival which was independent of the number of fractions in which the radiation was given. This could be of consequence in radiological protection