Subsequent 18F-PSMA PET/CT was performed following recovery from bowel resection. On the MIP PET image (A), there is normal distribution of radiotracer uptake with residual primary prostate cancer appreciated in the prostate gland and no residual abnormal foci in the left abdomen and left pelvis. On fused axial PET/CT images (B) and contrast-enhanced CT scan (C), a clean surgical anastomosis is appreciated. On the fused sagittal 18F-PSMA PET/CT image (D), PSMA-avid primary prostate disease is appreciated. Fluciclovine, also known as anti–1-amino-3-fluorocyclobutane-1-carboxylic acid, is an analog of the amino acid L-leucine, which is taken into cells by multiple amino acid transporters, including large neutral amino acid transporter (LAT) and alanine-serine-cysteine (ASC).1,2 Fluciclovine PET/CT shows activity at areas of increased protein turnover and DNA/RNA synthesis. Multiple reports have demonstrated fluciclovine activity in malignancies other than prostate cancer including breast, lung, colon cancer, hepatocellular carcinoma, multiple myeloma, squamous cell carcinoma, glioblastoma, and nerve sheath tumors. These cancers all demonstrated upregulated amino acid transport. In particular, the colorectal cancer cell line DLD-1 has been shown to strongly express LAT1 receptor activity, and the colorectal cancer cell lines Caco-2 and HT-29 demonstrated some ASCT2 activity, similar to the receptors used to take up fluciclovine activity in prostate cancer3–6 LAT1 receptor activity is theorized to be related to hypoxia and correlates to VEGF expression, a key regulator of angiogenesis in cancer.7 One subtype of treatment-resistant colorectal cancer, KRAS mutated, is associated with increased expression of ASCT2.8 Both ASCT2 and LAT1 are investigational targets for future therapies, including microRNA treatment.9 Both prostate and colorectal cancers have been linked to dietary and genetic factors with ongoing research in these areas.10