Single inhalation exposure to 90SrCl2 in the Beagle dog: late biological effects

Young adult Beagle dogs were exposed once to aerosols containing 90SrCl2 to obtain initial body burdens ranging from 2.5 to 250 μCi 90Sr/kg body weight (92 to 9250 kBq) and subsequently observed throughout their life span. All of the dogs are now dead. Radiation-induced lesions were confined to the bone, bone marrow, and adjacent soft tissue. Forty-five primary bone tumors occurred in 31 of 66 exposed dogs. Metastasis occurred from 21 tumors with the lung being the most frequent site of metastasis (76%). Twenty-seven were classified as different subtypes of osteosarcoma, 14 as hemangiosarcomas, 3 as fibrosarcomas, and 1 as a myxosarcoma. Four carcinomas arising from soft tissues adjacent to bone were also considered to be 90Sr-induced. In contrast to bone tumors arising in Beagle dogs chronically exposed to 90Sr through ingestion, histologic lesions of radiation osteodystrophy were minimal in this study, indicating that these lesions are not a necessary precursor of osteosarcoma development. The incidences of hemangiosarcomas (31%) and telangiectatic osteosarcomas (11%), in addition to osteosarcomas, suggest that the cell of origin for all of these neoplasms may be a multipotent mesenchymal cell with the potential for various morphologic expressions dependent upon local environmental factors. 7 references, 1 figure, 2 tables