Dual-Tracer PET/CT Protocol with [ 18 F]-FDG and [ 68 Ga]Ga-FAPI-46 for Cancer Imaging: A Proof of Concept

Imaging studies with PET tracers acting as fibroblast activation protein inhibitors (FAPIs) show promising results that could usefully complement [ F]-FDG in cancer imaging. All patients received [ F]-FDG PET/CT and dual-tracer PET/CT after an additional injection of [ Ga]Ga-FAPI-46 after the [ F]-FDG PET/CT. Two readers visually compared detection rate and analyzed target-to-background ratios for tumor and metastatic tissue in single- and dual-tracer PET/CT. Detection rate in dual-tracer PET/CT was visually as good as that in single-tracer PET/CT in 4 patients and superior in 2 patients, whereas target-to-background ratios were significantly higher in dual-tracer PET/CT. Dual-tracer [ F]-FDG/[ Ga]Ga-FAPI-46 PET/CT within a single session is feasible and has potential. The dual-tracer approach may have superior sensitivity to [ F]-FDG PET/CT alone without compromising individual assessment of either scan.