Quantitative studies on recovery from whole body irradiation in mice. III. A comparison of daily exposure to fast neurtron and gamma radiations.

Abstract

Damage from and adaptation to, various periods of continuous daily irradiation has been assessed by the amount of acute lethal injury produced by an additional large single dose. There was no qualitative difference between fast neutrons from fission and 60Co γ rays: the r.b.e. was about 6. At the dose levels used in our experiment there was no killing by acute intestinal damage, the intestine was demonstrated to be little affected and there was also no evidence that the r.b.e. changed with exposure time. The observations of others that the r.b.e. of fast neutrons and γ rays did change with changes in exposure time when this is 24 hours and less may be related to the occurrence of acute intestinal deaths after such exposures and to the differential sensitivity of the small intestine to fast neutrons.