Induction of neoplasia by 140Ba in mice

C57Bl mice of both sexes were given intraperitoneal injections of 140Ba-nitrate at 3 different dose levels (55.5, 37.0 and 18.5 kBq/g b.w.). Osteosarcomas were found in all groups and the osteoblastic type was the most common. In the middle and the highest dose groups, female mice developed tumours more frequently than the males. The irradiation doses were calculated to the femur, lumbar vertebrae and sternum and turned out to vary between 6 and 0.7 Gy.