[Morphology of yttrium-90 treated experimental arthritis].

A rheumatoid arthritis was produced in rabbits according to the method described by Klinge. It was treated with a single dosage of 2 mCi Yttrium-90. After 3 weeks the animals treated with Yttrium showed less fibrosis of the synovial membrane than the controls. After 6 weeks the synovial membrane of the non-treated controls showed considerable fibrosis but the synovial villi of the treated animals were slender and largely unchanged.