Examples of PET tumor-specific tracers that show uptake in skeletal metastases include 18F-FDG (cellular glycolysis), 18F-choline (cellular choline kinase activity and membrane turnover), and 68Ga-prostate-specific membrane antigen (68Ga-PSMA; cellular PSMA expression in prostate and some other cancers).(28–30). Here, FOLH1 is linked to cancer.