Radionuclide labelled starch granules as organ imaging agents

Efforts to overcome deficiencies in prior organ-scanning techniques have led to interest in the use of technetium-99m as the preferred radiolabel for diagnostic agents. An invention is described that relates to scintigraphic scanning, particularly to organ-specific carriers for technetium-99m. The process involves preparing a physiologically acceptable, water-insoluble, particulate radionuclide carrier by contacting an anionic starch derivative (about 1% to about 20% by weight of anionic substituents) with an acid solution of a reducing agent. The reducing agent is employed in an amount sufficient to provide from about 0.1% to about 0.5% by weight of reducing agent bound to starch derivative in the carrier. The type and amount of reducing agent may be varied. The particulate carrier then can be contacted with a radionuclide (technetium-99m) to form a radiolabelled scintigraphic agent. (JTA)