OBJECTIVE(S) In this work a new possible agent for radiosynovectomy has been targeted for articular pain palliation. MATERIALS AND METHODS Lu-177 of 2.6-3 GBq/mg specific activity was obtained by irradiation of natural Lu2O3 sample with thermal neutron flux of 4 × 10(13) n.cm(-2).s(-1). The product was converted into chloride form which was further used for labeling of (177)Lu-phytate complex and checked using ITLC (MeOH: H2O: acetic acid, 4: 4: 2, as mobile phase). The complex stability and viscosity were checked in the final solution up to seven days. The prepared complex solution (100 µCi/100 µl) was injected intra-articularly to male rat knee joint. Leakage of radioactivity from injection site and its distribution in organs were investigated up to seven days. RESULTS The complex was successfully prepared with high radiochemical purity (>99.9 %). Approximately, the whole injected dose has remained in injection site seven days after injection. CONCLUSION The complex was proved to be a feasible agent for cavital radiotherapy in oncology and rheumatology.