Subjects with gastrointestinal tumors underwent contemporaneous 18F-AlF-FAPI and 18F-FDG PET/CT either for an initial assessment or for recurrence detection. Tumor uptake was quantified by the maximum standard uptake value (SUVmax). The numbers of positive tumor lesions of 18F-FDG and 18F-AlF-FAPI PET/CT were recorded by visual interpretation. The sensitivity, specificity, and accuracy of 18F-AlF-FAPI, 18F-FDG PET/CT were calculated and compared to evaluate the diagnostic accuracy.
