Age dependency of response of the mouse skin to single and multifractionated gamma irradiation.

The age dependency of the response of the mouse skin to gamma-ray irradiation was studied using early skin reaction as an end point. The isoeffect doses for almost all the given levels of early skin reaction were, even though statistically not significant, approximately 10% larger on the average for 38- and 64-week-old mice than for 12-week-old mice. No significant difference between 12-week-old mice and 64-week-old mice was observed in the proportion of dose recovered during multifractionated exposures and in the slope of the fraction number and isoeffect dose relationships plotted on a log-log scale, as well as in the effects of anatomical location on the radiosensitivity. A preliminary shaving made the mouse skin relatively sensitive to radiation, and the dose-modifying factor was smaller for 64-week-old mice than for 12-week-old mice.