Development of (166)Ho-phytate Complex for Radiosynovectomy.

Background: (66)Ho-chloride was obtained by bombardment of natural Ho(NO3)3 dissolved in acidic media using thermal neutron flux (4-5 × 10(13) n.cm(-2).s(-1)).

Methods: (166)Ho-holmium chloride (185 MBq) was used successfully for preparation of (166)Ho-phytate complex with high radiochemical purity (>99.9 %, ITLC, MeOH: H2O: acetic acid, 4: 4: 2, as mobile phase). The complex stability and viscosity were checked in the final solution up to 2 days. The prepared complex solution (60 μCi/100 μl) was injected intraarticularly to male rat knee joints. Leakage of radioactivity from the injection site and its distribution in organs were investigated up to 2 days.

Results: Approximately all of the injected dose had remained in the injection site 2 days after injection.

Conclusion: The complex was proved to be a feasible agent for cavital radiotherapy in oncology and rheumatology.