Preparation of Holmium-166 Labelled Macroaggregates for radionuclide synovectomy

Radionuclide synovectomy (radiation synovectomy) is an alternative method that cures patients with rheumatoid arthritis diseases without surgery. During treatment, the suspension of the (166)Ho-macroaggregates radioactive particles ((166)Ho-MA) is administrated via intra-articular injection into the target joint to destroy the inflamed synovium.

The isotope of (166)Ho (E(beta) max = 1.84 MeV, T((1/2)) = 26.8 hr) was prepared by the (165)Ho(n, gamma)(166)Ho reaction in the LWR-15 nuclear reactor (8-10 MW) using approximate neutron flux 10(14) cm-2s-1.

The particles of Ho-Macroaggregates with suitable dimension 1-20 microm and the mean diameter of 8.5 microm were prepared. High in-vitro stability was obtained after incubation of neutron-irradiated Ho-Macroaggregates in saline solution (0.9% NaCl). The in-vivo stability on rats was verified as well.

High in-vivo and in-vitro stability as well as supporting gamma radiation of Ho-166 make the Macroaggregates a prospective agent for radionuclide synovectomy. The method of preparation is relatively easy and allows for the production of particles of a suitable dimension with a sufficient amount of radioactivity of Ho-166 for the treatment of the rheumatoid arthritis.