TIME AND DOSE-RELATED CHANGES IN THE THICKNESS OF PIG SKIN AFTER IRRADIATION WITH SINGLE DOSES OF SR-90/Y-90 BETA-RAYS

Time-related changes in pig skin thickness have been evaluated using a non-invasive ultrasound technique after exposure to a range of single doses of Sr-90/Y-90 beta-rays. The reduction in relative skin thickness developed in two distinct phases: the first was between 12 and 20 weeks postirradiation. No further changes were then seen until 52 weeks postirradiation when a second phase of skin thinning was observed. This was complete after 76 weeks and no further changes in relative skin thickness were seen in the maximum follow up period of 129 weeks. The timings of these phases of damage were independent of the radiation dose, however, the severity of both phases of radiation-induced skin thinning were dose related.