DAILY TOTAL-BODY EXPOSURES OF PRIMATES TO PROTON-, X-, OR GAMMA RADIATION: THE HEMATOLOGIC RESPONSE

In the course of space exploration, man may be exposed to relatively small but significant daily doses of high-energy proton radiation from solar flares. These doses might not be high enough to produce symptoms, but could produce changes in the number of peripheral blood cells. Rhesus monkeys were exposed in groups to daily, pulsed doses of 3-, 5-, 8-, 10-, 15-, or 20 rads from 150-Mev protons. Other groups were similarly exposed to pulsed 300-kvp x-rays. Still others were exposed continuously to cobalt-60 gamma radiation for a total dosage within 22 hours of 5-, 10-, 15-, or 20 rads. Assuming that the ratio of the dynamics of the changes in the peripheral blood counts from pulsed proton exposures (Pp) to those from pulsed x-rays (Px) would be the same as the ratio of the dynamics of the changes in the peripheral blood counts from continuous proton exposures (Cp) to those from continuous gamma exposures (Cg) (i.e., Pp:Px = Cp:(Cg), the unknown (Cp) could be deduced. Results suggest that the ratio Pp:Px is exceedingly close to unity, and that the ratio of Pp (or Px): Cg) is between 1.5 and 1.6 to 1. Consequently, the effect of continuous proton exposure within these daily dose increments can be predicted. (Author)