Radiosensitivity of pre-irradiated mouse skin to second courses of single and multi-fractionated irradiation--skin shrinkage.
The hind legs of mice were re-irradiated with various gamma-ray doses in single or multi-fractionated exposures 6 or 12 months after conditioning irradiation was administered using a variety of treatment schedules. Dose-response relationships were evaluated to ascertain "residual injuries", permissible doses during the second treatments. Fifty to 60 days after the second treatments, the degrees of shrinkage of the skin on the dorsal aspects of the hind legs were measured and used as endpoints. The residual injuries were affected by the biologically effective doses, or by the treatment schedules of not only the first, but also the second exposure. The higher the biologically effective doses, the greater were the residual injuries. Compared to the previously untreated skin, the pre-irradiated skin was relatively radioresistant to the second course of treatments, regardless of the treatment schedule used. The response of the pre-treated skin to a given test dose (25 or 40 Gy) lessened with increasing dose for each treatment schedule used during the first treatment course.
Jingu
K
K
Department of Radiology, Faculty of Medicine, Kyushu University, Japan.
Masuda
K
K
Withers
H R
HR
Hunter
N
N
D000818:Animals; D004307:Dose-Response Relationship, Radiation; D005260:Female; D051379:Mice; D011829:Radiation Dosage; D011833:Radiation Injuries, Experimental / Q000473:pathology; D011836:Radiation Tolerance; D012867:Skin / Q000473:pathology / Q000528:radiation effects*