Preparation of .sup.166Dy/.sup.166Ho-chitosan as an in vivo generator for radiosynovectomy

.sup.166Ho is one of the most effective radionuclides used for radiosynovectomy. One method to deliver this radioisotope to target tissue is via the .sup.166Dy/.sup.166Ho in vivo generator system. The aim of this work was to prepare .sup.166Dy/.sup.166Ho-chitosan (.sup.166Dy/.sup.166Ho-CHIT) in vivo generator for radiosynovectomy applications. .sup.166Dy obtained by the irradiation of natural .sup.164Dy target. .sup.166Dy was separated from .sup.166Ho by extraction chromatographic method (separation yield; 93% and separation factor;1.7). Chitosan labeling was performed in acetic acid with 99.3 ± 0.6% radiochemical purity. Biodistribution studies on intraarticular injected rats demonstrated high retention in the knee joint even 7 days showing no radioactivity leakage from the injection site into other organs as well as any translocation of the daughter nucleus after [beta].sup.- decay of .sup.166Dy.