X-Irradiation of the Exteriorized or in Situ Intestine of the Rat

Information concerning the effects of ionizing radiations on the intestine, other than those due to X- or neutron irradiation, is scarce. We began our studies of intestinal radiation injury by making observations after exposures to external radiation. These changes could then be compared to the lesser known damage found after radiosotope ingestion. Oral administration of poorly absorbed radioisotopes affords an exposure that is fairly well limited to the intestine. In order to compare the effects of such isotopes with those seen after exposure to external radiation, the region irradiated by an external source should be similarly restricted. This may be done either by irradiating the abdominal region or by irradiating the surgically exteriorized intestine while shielding the remainder of the body. In this paper are reported the results of the first phase of these comparative studies, which were obtained after exposures to external radiation. Data obtained after administration of single doses of poorly absorbed a- and -- emitting isotopes will be reported later (11). METHODS