DYSPROSIUM (DY-165) HYDROXIDE MACROAGGREGATES FOR RADIATION SYNOVECTOMY - ANIMAL STUDIES

This paper reports the development of a new chemical formulation, Dy-HMA, to utilise the advantages of dysprosium 165 in radiation synovectomy of certain forms of arthritis. Dy-HMA is a sterile suspension of dysprosium hydroxide macroaggregates (approximately 6 mg Dy/ml) in saline with the majority of particles in the 3-5 μm range. The absence of ferric hydroxide and a higher concentration of dysprosium in the formulation offer advantages over dysprosium ferric hydroxide macroaggregates, Dy-165-FHMA. Biodistribution studies in rats and rabbits with Dy-HMA show less leakage than with Dy-FHMA and considerably less leakage than with yttrium silicate colloid. Rabbits treated with intraarticular injections of Dy-HMA equivalent to 10-30 times the typical clinical dose showed no signs of any toxic effects. © 1990 Springer-Verlag.