Indium 113m is a transition metal obtained by eluting a tin 113 generator system with HCl. The complexing ability of the eluted indium allows for one-step chemical preparation of organ specific scanning agents. Indium transferrin is used for plasma volume estimation and cardiac blood pool-placental scanning; indium phosphate colloids are used for reticuloendothelial scanning, i.e., liver, spleen and bone marrow; indium DPTA chelates are used for brain and kidney scanning; and indium-iron hydroxide macroaggregate is used for perfusion lung scans. Clinical experience in over 1,000 patients suggests that these agents are at least as effective as previous scanning radiopharmaceuticals. The short half life of the indium (100 minutes) and the long half life of the tin (118 days) allow for frequent elution of the generator in a clinical setting. This markedly decreases cost and obviates the need for storage of various isotopes at varying decay rates. The one-step process also eliminates the need for sophisticated radiochemical preparation prior to each scan. This availability of an inexpensive broad spectrum scanning agent may permit a more widespread application of diagnostic nuclear medicine procedures where they are now not feasible.