Strontium-90-Induced Bone Tumors in Miniature Swine

Fourteen bone tumors, classified as either osteosarcomas or giant cell tumors, have occurred in nine Pitman-Moore strain miniature swine chronically exposed to⁹⁰ Sr. Five had been exposed by daily feeding of 125 μCi of⁹⁰ Sr, and two had received single intravenous injections of 64 μCi/kg body weight. Two had been weaned from 625 μCi/day sows and were fed 156 μCi/day for a short time, followed by no additional radionuclide feeding. The majority (12) of the tumors occurred in the skull, including the mandible and maxilla, and in most cases appeared to arise from sites of severe radiation osteonecrosis where bone resorption and fibrosis was prevalent. Of significance was the observation that in each case where it was possible to determine the origin, the bone tumors arose near or within the periosteal surface of the bone.