Production of 105Rh-EDTMP and its bone accumulation.

105Rh has favorable physical characteristics as a radiotherapeutic nuclide. Carrier-free 105Rh can be produced by the neutron activation of 104Ru followed by beta decay of 105Ru. It was clarified that carrier-free 105Rh can be produced in quantities and the purity necessary for chemical and clinical investigations of its use as a nuclide for radiotherapy. 105Rh-EDTMP was simply obtained from 105Rh3+ and EDTMP by heating for 30 min in boiling water, giving a radiochemical yield of > 99%. Dissociation of radioactivity assessed by paperchromatography was negligible for up to 5 days after its preparation. In animals, 105Rh-EDTMP showed rapid blood clearance and selective uptake in the bone. Hence, 105Rh-EDTMP is thought to be a promising therapeutic agent for the treatment of pain due to bone metastases.