Computerized double-tracer subtraction scanning with gallium-67 citrate in inflammatory diseases.

A gallium-67/technetium-99m subtraction technique was used with a variable weighting factor. That is, each image was separately set to 100%. Varying amounts of the Tc-99m images were subtracted from those of Ga-67. A total of 95 patients who had radiogallium scanning for suspected inflammatory disease were studied by the subtraction technique. Thirty of these patients had abnormal Tc-99m pyrophosphate bone scans, while 20 had abnormal radiogallium abdominal foci; 45 had defects in liver, spleen, or kidney images. The subtraction technique with variable weighting was highly successful in enhancing hot-spot visibility, and in providing information as to the anatomic location of the defect.