An improved means of detecting upper abdominal abscesses using the dual radionuclide subtraction technique was applied to 51 patients. 67Ga citrate was used in the localization of the lesion and 99Tc-labeled human albumin microspheres and 99Tc sulfur colloid were used for subtracting out the interfering background from normal organ concentrations. The procedure provided the parameter capabilities for localization of the abscesses as well as information on their shape and size. Compared to nonsubtraction Ga procedures, 53% more abscesses were diagnosed using the subtraction technique.