Generator systems producing short lived nuclides from longer lived parents have distinct clinical advantages. They are more economical, result in a lower radiation dose, and can make short lived scanning readily available even in areas remote from rapid radiopharmaceutical delivery services. The 113Sn-113mIn generator has the additional advantage that, as a transition metal, Indium can be readily complexed into organ specific preparations. 113Sn, a reactor produced nuclide with a 118 day half life, is absorbed on a zirconium or silica gel column. the generator is eluded with 5 to 8ml of 0.05 N HCL solution at pH 1.3-1.4. The daughter nuclide, 113mIn, has a half life of 1.7 hours and emits a 393 Kev monoenergetic gamma ray. Previous methods for labeling organ specific complexes with 113mIn required terminal autoclaving before injection. With the recent introduction of serile, apyrogenic 113Sn-113mIn generators, we have developed a simplified technique for the laboratory preparation of Indium labeled compounds. This method eliminates autoclaving and titration enabling us to pre-prepare organ specific complexes for blood pool, liver, spleen, brain, kidney and lung scanning.