Histologic study of effects of radiation synovectomy with Rhenium-188 microsphere

Rhenium-188 microsphere is a relatively new radiation synovectomy agent dev eloped for the treatment of rheumatoid arthritis. It has been shown that th e levels of unwanted extra-articular radiation are negligible with this age nt. A histologic study was conducted to assess the effect of radiation syno vectomy on synovium and articular cartilage after intra-articular injection of various doses of Re-188 microspheres into the knee joints of rabbits. I ntra-articular injection of Re-188 microspheres into rabbit knee joints res ulted in mild reactive inflammation and thrombotic occlusion of vessels whi ch subsided rapidly. Sclerosis of subsynovium could be seen 12 weeks after injection. No evidence of damage to articular cartilage was noted. There wa s no significant difference in the articular pattern after injection of 0.3 or 0.6 mCi Re-188 microspheres. This study suggests that a treatment dose of Re-188 microspheres causes transient inflammation of synovium without an y detectable damage to the articular cartilage of knee joint. (C) 2001 Else vier Science Inc. All rights reserved.