Occurrence and distribution of bone tumors in beagle dogs exposed to 90Sr.

Radiation-induced bone tumors in beagle dogs exposed to 90Sr have been evaluated in terms of their incidence, time of appearance, occurrence as multiple tumors, anatomic distribution, and the influence of sex on their development. Among dogs fed 90Sr during skeletal development, the incidence of bone tumors was dose dependent. Tumors thus appeared in 10 of 19 dogs receiving average skeletal doses of 130 Gy, 15 of 60 receiving 97 Gy, 5 of 61 receiving 61 Gy, 2 of 65 receiving 26 Gy, and 1 of 40 receiving 1.3 Gy. No tumors appeared among 66 dogs who received 8 Gy, 78 who received 0.3 Gy, and 80 non-irradiated controls, all of which have been observed for life. Among dogs given a single intravenous injection of 90Sr in early adulthood, tumor production was somewhat higher than among 90Sr-fed dogs at the same radiation dose: bone tumors were present in 6 of 25 dogs who received 62 Gy and 1 of 20 dogs who received 7.5 Gy. Bone tumors appeared sooner and were more often multiple in animals receiving the higher doses. Long bones were the sites of most of the tumors appearing after the highest dose level. Bones of the head, particularly the mandible, were the predominant site of tumors in the next highest dose level group.