Gallium 68–labeled fibroblast-activation protein inhibitor PET/CT was superior to fluorine 18 fluorodeoxyglucose PET/CT for the staging of biliary tract cancer. Background Gallium 68–labeled fibroblast-activation protein inhibitor (68Ga-FAPI), an imaging agent for detecting tumors, represents a promising alternative to fluorine 18 fluorodeoxyglucose (18F-F...