Abstract: Small sized material (less than 0.2 .mu.m, preferably less than 0.1 .mu.m) comprising a complex of (1) denatured albumin, particularly human serum albumin and (2) a metal reducing agent, particularly a stannous reducing agent, preferably formed in the presence of a stabilizing ligand, which complex, when labelled with technetium-99m provides an excellent agent for imaging or otherwise evaluating reticuloendothelial systems (RES) and/or components thereof, particularly the bone marrow, liver and/or lymphatic system; methods of making and using the same; a complex (physical or chemical) of technetium-99m with such materials and methods of using such latter complex.

Abstract: Microaggregates of a complex of (1) albumin, particularly human serum albumin and (2) a metal reducing agent, particularly a stannous reducing agent, preferably formed in the presence of a stabilizing ligand, which complex, when labelled with technetium-99m provides an excellent agent for imaging reticuloendothelial systems (RES), particularly the liver, spleen, and bone marrow; methods of making and using the same; a complex (physical or chemical) of technetium-99m with such microaggregates and methods of using such latter complex.

Abstract: Diagnostic compositions comprising serum albumin which has been treated to remove fats and fatty acids with possible changes in molecular conformation, a reducing agent, preferably a stannous reducing agent, and a radionuclide, preferably technetium-99m, are highly useful in study and diagnosis of morphology and functions of animal tissues and organs, particularly in studying cardiovascular dynamics, placental imaging, cisternography, in determining blood and plasma volumes, in metabolism and turnover studies, in radioscintigraphic diagnosis of the lung and reticuloendothelial systems, e.g. pulmonary emboli, bronchogenic carcinoma, pneumonitis, emphysema, tuberculosis, pathology of liver and/or spleen manifest by changes in size or shape or pathology of adjacent structures or displacement of these organs, and other disorders.For pulmonary and reticuloendothelial applications, the albumin is converted to particulate forms by denaturation under conditions which form aggregates of appropriate size.