Rhenium heptasulfide: a potential carrier system for radiation synovectomy.

Rhenium sulfide colloid was prepared by the thiosulfate acid reduction method and assessed for its applicability as a particle carrier for use in radiation synovectomy. In vitro stability studies demonstrated that greater than 95% of the 186Re activity remained in colloidal form over a 5 day period. Intraarticular knee injections of 186Re2S7 into normal and arthritic rabbit joints were followed by gamma camera imaging and by biodistribution in order to quantify the leakage to different organs. Mean retentions of 186Re in knees, determined by gamma camera imaging were 97(+/- 4)%, 92(+/- 7)%, 89(+/- 9)% and 88(+/- 10)% at 1 h, 1, 2 and 3 days, respectively. The percent injected dose was 0.0023% in the lymph nodes, 1.65% in the liver, 0.006% to the spleen, 0.013% in the lungs, 0.35% in the kidney, 0.014% in the heart, 0.12% in the bone, 0.7% in the muscle, 0.3% in the fat and 0.6% in the blood.