Delayed Effects of Proton Irradiation in Macaca Mulatta. II. Mortality (15-Year Report).
Interim rept. 1964-1982,
SCHOOL OF AEROSPACE MEDICINE BROOKS AFB TX
Pagination or Media Count:
A radiation primate colony of 57 controls and 301 217 proton exposed subjects has been followed since 1964. Lifespan of both the exposed and, more specifically, the proton-exposed subjects in the chronic colony was shortened. Energies of 55 MeV and greater decreased life span as did doses in excess of 360 rads. Females were more sensitive to lower doses than males. They died earlier in doses as low as 25-113 rads and in all energies tested except 55 MeV. Survival curve analysis found no difference among the onset of death in the 3 highest energies 138, 400, and 2300 Mev however, its onset was earlier in the 32-MeV exposure and later in the 55-MeV exposure and later in the 55-MeV exposure than the total penetrating energies greater than or equal to 138 MeV. Dose ordering effects were evident. In contrast to the controls, mortality rates began to accelerate at approx. 8 years in the 360-400-rad group at approx. 2 years in the 500-650-rad group and approx. 1 year in the 800-rad group. The leading causes of death among the proton-exposed animals were primary infections approx. 30, endometriosis 25, and organ degeneration approx. 17. Malignant tumors accounted for 18 of the deaths. If endometriosis is included in this group, the mortality from all forms of neoplastic conditions is 43 in the proton-exposed animals.