Subtraction scintigraphy with 67Ga-citrate and 99mTc-colloid in the diagnosis of intrahepatic masses.

Subtraction scintigraphy of the liver with 67Ga-citrate and 99mTc-colloid (99mTc-phytate) was performed by subtracting the image of the latter from the image of the former in 34 patients who were suspected of having intrahepatic masses, especially hepatoma. The computer used was Scintipac 1200 (32 KW memories and 2.4MBX2 disk memories). Both images were taken in a digital form (128 X 128 elements). After normalizing both images, 4 different factors (0.6, 0.8, 1.0, and 1.2) were applied to the 99mTc image before the subtraction from the 67Ga image. We found that this technique was very useful for the detection of abnormal 67Ga accumulation in the liver.