PERFORMANCE OF MINIATURE PIGS AFTER PARTIAL BODY IRRADIATION
ARMED FORCES RADIOBIOLOGY RESEARCH INST BETHESDA MD
Pagination or Media Count:
Thirty-two miniature pigs were trained by shock avoidance conditioning to traverse a two-chambered shuttlebox. Eight unshielded pigs whole-body exposed received midline tissue doses MTD of about 13,000 rads of pulsed, mixed gamma-neutron radiations to the head and trunk. Eight head- shielded and eight trunk-shielded pigs received doses to the unshielded part of the body that were equivalent to the doses received by unshielded animals. Four trunk-shielded pigs received 6000 rads to the head, and four others received 3000 rads to the head. MTD behind the shield at the middle of the head or trunk was less than 7 percent of the MTD to the same point without a shield in place. Postirradiation performance was evaluated. All unshielded pigs suffered early transient incapacitation ETI or immediate, permanent complete incapacitation PCI several early deaths within 4 hours occurred among these animals. Head shielding prevented ETI, immediate PCI, and early deaths, but trunk shielding did not. However, trunk-shielded subjects that escaped the early death performed and survived longer than most head-shielded or unshielded pigs. ETI occurred in all of the trunk-shielded pigs that received 6000 rads and in one of four that received 3000 rads however, early deaths did not occur and survival times were much longer than those previously reported for unshielded pigs that received comparable doses.