Preparation of ۱۹۱Os–phytate, an in-vivo radionuclide generator, for radiosynovectomy application

۱۹۱Os is a parent radionuclide with a ۱۵.۴ d half-life. It decays by beta emission to ۱۹۱mIr, which is a radionuclidewith a ۴.۹۶s half-life. It decays by the isomeric transition to stable ۱۹۱Ir, emitting a ۱۲۹-keV gamma photon. In thisstudy, ۱۹۱Os–phytate was developed into an in-vivo radionuclide generator for simultaneous radiosynovectomy and imaging. ۱۹۱Os-hexachloroosmate was used to prepare ۱۹۱Os–phytate (۱۰۰ μCi/۵۰ μl) using reaction condition optimization followed by an intraarticular injection to rat knee joints. Also, its distribution and stability were assessed. The imaging of ۱۹۱Os cation and ۱۹۱Os–phytate was performed by SPCET. The ۱۹۱Os–phytate complex was obtained at pH=۵.۵ with normal saline at room temperature. Radio-TLC showed an overall radiochemical yield of ۹۵-۹۸%. The complex was injected into the rats’ knees, and the whole injected dose remained at the injection site even three days after injection. Due to the stability and retention of the complex in joints approved by biodistribution and imaging studies, the complex is a potential in vivo generator for cavital radiosynovectomy of minor joints.