Tumor imaging with carbon-11 labeled alpha-aminoisobutyric acid (AIB) in patients with malignant melanoma.

The potential usefulness of [C-11]-labeled alpha-aminoisobutyric acid (AIB) for tumor imaging has been demonstrated previously in our findings of increased tumor uptake with C-14-labeled AIB in human melanoma heterotransplants in nude mice, and subsequently, in a single case study using C-11 AIB to demonstrate the extent of metastases in patient with widespread malignant melanoma. We report here on the use of C-11 AIB in ten patients with metastatic or unresectable malignant melanoma. Five patients had intense tracer uptake at all known sites of tumor involvement. A sixth patient had good uptake in metastatic lesions in the shoulder and the pelvis, but did not demonstrate uptake within metastatic lesions in the lungs. Two patients had only minimal uptake over the tumor lesions while the two other patients had essentially normal studies. Further studies with C-11 AIB in patients with melanoma and other tumors are warranted.