Late effects of mixed gamma-neutron and x-radiation have been studied in swine from 2 years postirradiation throughout the remainder of their life span. Clinical changes were similar in the irradiated and controls except for unilateral atrophy of the musculature in some of the irradiated individuals surviving doses of bomb radiation above 250 rads. The major causes of death were chronic diseases. Thus the usual clinical syndrome was loss in body weight, debilitation, bacterial infection, and the usual blood changes associated with infections. Pathological lesions presumably attributable to effects of ionizing radiation were: asymmetrical conformation with diminution in the respective sizes of the musculature and underlying bone in the pelvic region, usually in one pelvic limb; genital neoplasia, commonly manifested as leiomyomas of the broad ligaments and uteri; hepatomas; and annular, sclerosing adenocarcinomas usually present as strictures in the posterior one-third of the small intestines. Mean postirradiation survival times for the irradiated swine, all doses combined, were: 8.3 years (males) and 7 years (females); and for the controls, 9 years (males) and 7.9 years (females). The mortality rate was higher in the irradiated animals through approximately 7 years postirradiation. Regression of survival time on dose for the combined data of both sexes indicated life shortening was approximately 3% per 100 rads.

This content is only available as a PDF.
You do not currently have access to this content.