Yttrium 90 in persistent synovitis of the knee - a single centre comparison. The retention and extra-articular spread of four 90-U radiocolloids.

The characteristics of three colloidal preparations of 90-Y currently used for the irradiation of chronic synovitis of the knee have been studied. One, 99-Y silicate, showed less leakage away from the joint than the other two preparations, 90-Y ferric hydroxide and 90-Y citrate. Comparable amounts of 90-Y were taken up regional lymph nodes when the silicate and ferric hydroxide forms were used; the greatest irradiation of regional lymph-nodes occured using the citrate form. In this respect all three preparations are inferior to the previously used preparation 90-Y resin colloid which is no longer manufactured.