Radiosensitivity of Mice as a Function of Age

RF female mice (l421) of ten age groups (2 to 2l months) were given acute exposures (450 rads) of Cos0 gamma rays at l4-day intervals until death. The median lethal dose for each group was calculated and reduced to a corresponding equivalent acute dose to determine the effect of age on radiosensitivity. lt was concluded that radioresistance is relatively stable or unchanged through the first half of adult life, and then declines quite rapidly until the end of the normal life expectancy. (auth)