In cases where there is evidence of biochemical recurrence, in view of rising PSA, with a negative PSMA scan then imaging with the following radiopharmaceuticals may be considered: 18F-fluciclovine (which is internalized into prostate cancer cells by amino acid transporters LAT1-4 and ASCT1/2 which are upregulated in prostate cancer) or 11C/18F-choline (which targets increased cell membrane lipid synthesis which is increased in cancer cells) (16). This evidence concerns the gene SLC1A4 and prostate carcinoma.