CONCENTRATION OF STRONTIUM AT PREDILECTIVE SITES OF BONE TUMORS

Studies were made of the tissue distribution of Sr/sup 89/ intraperitoneal injection of carrier-free Sr/sup 89/ in a carcinogenic dose (2.5 mu c/g) in various strains of mice (CF/sub 1/ and Sprague-Dawley). Attempts were made to correlate Sr/sup 89/ localization with tumor sites by assays of ashed bone radioactivity up to 4 months after the injections. The relative radioactivity over a period of 120 days increased in proximal femur and skull, decreased in distal femur and proximal tibia, and did not change in the lumbar and sacral vertebrae. No direct relation between relative specific activity of any bone (at any sacrifice period) and the incidence of osteogenic sarcoma in it was noted. High values of relative activity are most consistently found in the lumbar spine, yet this area has a tumor incidence of less than 10%. The skull at 120 days has the greatest relative concentration, but develops only a few tumors, and these primarily in the jaws. The proximity of dental tissue, which has the highest initial Sr/sup 89/ concentration, contributes additive irradiation to jaw bone tissue, and renders this area different from all other parts of the skull. Whether an animal given Sr/sup 89/ develops bone tumors dependsmore » primarily upon administered dose, dose retained, dose absorbed, and dose rate. Local factors of susceptibility or resistance to tumor development overshadow the radioactivity burden and appear to be more intimately associated with differences in local metabolic processes. (H.H.D.)« less