Radiolabelling of pharmaceutical dosage forms by neutron activation of samarium-152

Samarium-152 can be activated in a neutron flux for labelling pharmaceutical dosage forms for evaluation by gamma scintigraphy. Samarium is incorporated as samarium oxide powder which is available with 152Sm in its natural isotopic abundance or isotopically enriched. The yield of 152Sm was reduced considerably following the neutron activation of the non-isotopically enriched oxide. This can be attributed to the high neutron capture by 149Sm present in the non-isotopically enriched oxide. In order to keep the mass of the added oxide powder to the minimum and also to reduce the neutron irradiation time, it is recommended that samarium oxide enriched with 152Sm should be used routinely when radiolabelling pharmaceutical dosage forms. (Author)