MUSCULAR FIBROSIS INDUCED AFTER PIG SKIN IRRADIATION WITH SINGLE DOSES OF IR-192 GAMMA-RAYS

Localized irradiation of the skin and subcutaneous tissues with large single doses of gamma-rays can induce delayed effects characterized by fibrosis which invades the irradiated tissues. In this study the dept h of penetration of muscle fibrosis was measured in the pig 30 weeks a fter irradiation of the skin surface with single doses of Ir-192 gamma -rays of 16-256 Gy. Irradiation was directed either to the outer side of the thigh or to the back, close to the mid-dorsal line. Fibrosis on ly developed in irradiated muscle after doses that induced moist desqu amation of the skin in the acute phase of the reaction, i.e. after ski n surface doses of 48-64 Gy. In skeletal muscles, the limit of fibroti c expansion was reached at a depth dose of 14+/-4 Gy (+/-SD) for skin surface doses exceeding 48 Gy.