Dual-tracer PET/CT protocol with [¹⁸F]-FDG and [⁶⁸Ga]Ga-FAPI-46 for cancer imaging - a proof of concept.

Imaging studies with PET tracers acting as fibroblast activation protein inhibitors (FAPI) show promising results that could usefully complement [18F]-FDG in cancer imaging. Methods: All patients received [18F]-FDG-PET/CT and dual-tracer PET/CT after additional injection of [68Ga]Ga-FAPI-46 following the [18F]-FDG-PET/CT. Two readers visually compared detection rate and analyzed target-to-background uptake ratios (TBRs) for tumor and metastatic tissue in single and dual-tracer PET/CT. Results: Detection rate in dual-tracer PET/CT was visually as good as that in single-tracer PET/CT in four patients and superior in two patients, whereas TBRs were significantly higher in dual-tracer PET/CTs. Conclusion: We demonstrate the feasibility and potential of dual-tracer [18F]-FDG-[68Ga]Ga-FAPI-46-PET/CT administered within a single session. The dual-tracer approach may have superior sensitivity to [18F]-FDG-PET/CT alone without compromising individual assessment of either scan.