DOSE-MODIFYING FACTORS FOR SKIN ULCERATION IN MOUSE LEGS EXPOSED TO GAMMA RAYS

Abstract

To assess the dose-modifying factors for skin ulceration, the hind legs of mice were irradiated using gamma-rays of various doses in single exposures. The skin ulceration began to occur 2 months after irradiation, after early skin reactions such as wet desquamation, had healed completely. No new skin ulceration was observed more than 8 months after irradiation even though the observations were continued until 12 months post-irradiation. The ulceration dose 50 (UD 50), a dose required to produce skin ulceration in from 2 to 8 months in 50% of the tested animals, was calculated for each treatment schedule. The preliminary shaving procedure reduced the UD 50 dose to 0.85 that of the untreated controls. The ventral aspect of the hind leg was more radioresistant to single-dose irradiation than was to the dorsal aspect. The UD 50 for the ventral aspect was 1.29 times that for the dorsal aspect when the skin had been previously shaved, and 1.46 times that for the unshaved control legs. The UD 50 was 7 and 14% larger when mice were kept in the dorsal rather than the abdominal position during irradiation, for the preliminarily shaved and unshaved skin, respectively.