A 29 year-old-man presenting with advanced metastatic malignant melanoma was successfully imaged using carbon-11 (11C) labeled alpha-aminoisobutyric acid (AIB), a synthetic, non-metabolized amino acid transported into viable cells by the A-type, or alanine-preferring, amino acid transport system. Tumor located in the hilum of the lung was well visualized with 11C-AIB prior to chemotherapy. A gallium image with liver subtraction using 99mTc-sulfur colloid demonstrated regions of increased activity in liver which correlated with regions of increased activity on the 11C-AIB liver image.