Abstract: The radioactive dysprosium lithium borate glass (DyLB) microspheres used for synovectomy were prepared. The biodegradability and biocompatibility of theses DyLB microspheres were investigated by in-vitro and in-vivo test. The DyLB microspheres reacted nonuniformly in simulated body fluid (SBF9) with more than 53wt% of lithium being dissolved, whereas nearly all of the dysprosium (>99.997wt%) remained in the reacted microspheres, after being immersed in SBF9 at 37℃ for 7d. For three different compositions, the weight loss of DyLB microspheres was 16%－43％ when they were immersed in SBF9 for 1d; After being immersed in SBF9 for 7d, the weight loss of these DyLB microspheres was up to (25%－55%), and the precipitationdissolution reaction reached equilibrium, indicating that the DyLB microspheres were partially biodegradable in SBF9. Furthermore, the DyLB microspheres had good biocompatibility, since no tissue damage or inflammation was detected after being implanted in the liver of rat for two weeks. After being neutron activation, the radionuclide purity of radioactive DyLB microspheres was over 99.9%, which can be used for radiation synovectomy treatment in clinic.

Key words: borate glass microspheres, biodegradability, biocompatibility, radiation synovectomy