Accumulation of 123I-IMP in extrahepatic metastases of hepatocellular carcinoma.

Twenty patients with 58 extrahepatic metastases of hepatocellular carcinoma (HCC) (41 bone, 5 lung, 6 peritoneum, 4 adrenal glands, 1 brain, 1 lymph node) underwent 123I-iodoamphetamine (123I-IMP) and gallium-67 (67Ga) scintigraphy. The rate of positivity with 123I-IMP planar imaging was 44% above the level of the diaphragm and 76% below the diaphragm, with an overall sensitivity of 62%. The combination of 123I-IMP scintigraphy and single photon emission tomography enabled positive visualization of an additional six metastatic foci: three in the adrenal glands, one in the peritoneum, one in the cranium and one in a rib. The rate of positivity with 67Ga planar imaging was 75% above the level of the diaphragm and 45% below the diaphragm, with an overall sensitivity of 58%. Our findings suggest that 123I-IMP is effective for detecting extrahepatic metastases of HCC, particularly those below the diaphragm.