Malignancy as a cause of death in nonsacrifice Segment III beagles receiving gamma radiation during development

As of December 31, 1978, 31 Segment III beagles had died or been euthanatized because of a malignant neoplasm. Twenty-five of the 31 had been irradiated. Fifteen of the 25 irradiated dogs were exposed at either 55 days postcoitus (dpc) or 2 days postpartum (dpp) to 20 or 100R. Of these 15, 4 dogs irradiated at either 55 dpc or 2 dpp died with malignancies prior to 2 years of age, an unusual occurrence in the dog. Eight irradiated and no control dogs developed malignant lymphoma. Four of the dogs with lymphoma were irradiated at 55 dpc. These findings suggest a relatively high sensitivity for radiation carcinogenesis in dogs exposed in the perinatal period