SELECTIVE ACCUMULATION OF SR-89 IN METASTATIC DEPOSITS IN BONE - RADIO-HISTOLOGICAL CORRELATION

The systemic administration of Sr-89 has proven effective in the palli ation of painful osseous metastases. Biodistribution studies with the gamma-emitter Sr-85 suggest that both its uptake and retention are inc reased in bone metastases, where increased mineral turnover takes plac e. To study the pattern and nature of this process further, bones cont aining metastatic deposits were obtained from three patients who had p reviously been treated with 148 MBq of Sr-89. The bones were cut into 0.5-1.0 cm sections. The cut surfaces which faced together were marked with India ink, and adjacent sections were submitted for histology an d autoradiography. Stronitium deposition and retention were observed i n regions which exhibited significant osteoblastic activity, mostly in areas adjacent to metastatic deposits, but also in subchondral and en dosteal locations, as well as in an area corresponding to a pathologic al fracture with callus formation. With these exceptions, strontium de position was not observed in histologically normal bone or within the marrow. Our findings demonstrate directly the selective nature of accu mulation and retention of Sr-89 and confirm previous clinical impressi ons.