Indium-114m in dual-nuclide studies with Cr-51: comparison with indium-111

Simultaneously radioassay of In-111 and In-114m, each in the presence of Cr-51, has been investigated. Presented here are data demonstrating the efficacy of using In-114m in a dual radioassay with Cr-51, a radiolabel currently used in many cellular research applications. In-111 (T1/2, 2.81 days) has recently received attention in clinical studies, but has less than satisfactory physical characteristics for animal studies involving two emitters or long-term recirculation. Indium-114m (T1/2, 50.1 days) permits long-term in vivo and in vitro monitoring, so that dual-nuclide studies on cell recirculation can be performed.