Lifetime effects of long-term exposures to strontium-90 and radium-226 in beagle dogs

Graded doses of injected 226Ra or ingested 90Sr were given to 804 beagles in early life. The median survival times of the various irradiated groups at higher exposures were lower than the control value of 14.7 years. The 226Ra group with the highest total skeletal dose had a median survival of 4.5 years. For 90Sr the highest group had a median survival of 2.2 years. Normal life spans were evident in treatment groups with average skeletal doses of <290 rads to the skeleton from 226Ra or of 2600 rads from 90Sr. The life-shortening effects of 226Ra and 90Sr are related to the tumors produced from the radionuclide exposure. The significant causes of death among the 226Ra-treated beagles were primary bone cancers, mostly osteosarcomas. Among dogs exposed to 90Sr, significant numbers of deaths were from primary bone cancer, myeloproliferative disease, and squamous-cell carcinoma of the gingiva. In general, more of these effects were produced in the groups receiving higher doses and dose rates; at lower doses the effects, when present, appeared later than they did at higher doses. 9 refs., 6 figs., 4 tabs