Retention and extra-articular spread of intra-articularly injected 90Y silicate

A study was performed on the retention and distribution of intra-articularly injected colloidal 90Y silicate in 7 patients with rheumatoid arthritis (8 knees). In 5 knees retention was complete within the limits of measuring accuracy, and in the remaining 3, 82-84% was retained. No radioactivity was detected in the liver and heart areas or in the blood samples. The cumulative urine activity was less than 1.8%. In the inguinal lymph nodes, activity was detectable %0.5-2%) in only 3 cases. We conclude that 90Y silicate is a safe radioactive agent for the treatment of knee effusions, provided the limb is strictly immobilized after the injection.