Clinical Explorations of [Ga] Ga-FAPI-04 and [F] FDG Dual-Tracer Total-body PET/CT and PET/MR Imaging.

Fibroblast activation protein inhibitor (FAPI) and [F]fluorodeoxyglucose ([F]FDG) provide complementary biological information, and FAPI/FDG dual-tracer imaging clinical application is increasing recently. However, optimal protocols for FAPI/FDG dual-tracer positron emission tomography/computed tomography (PET/CT) and PET/magnetic resonance (PET/MR) imaging are still under investigation. Due to its high sensitivity, total-body PET/CT allows for imaging with minimal tracer activity and supports the creation of new dual-tracer PET/CT imaging protocols. PET/MR, with its multiparametric MR imaging, provides additional biological information for diagnosis. Studies have investigated the clinical feasibility of low-activity PET/MR imaging, yielding promising results. As there are still few institutions in the world that have experience with the advances provided by the use of total-body PET/CT and equipped with a PET/MR scanner, we have discussed the clinical explorations to reduce radiation exposure and optimize workflows for [Ga]Ga-FAPI-04 and [F]FDG dual-tracer PET/CT and PET/MR imaging. The review also provides potential new clinical explorations of [Ga]Ga-FAPI-04 and [F]FDG dual-tracer total-body PET/CT and PET/MR imaging, including dual-tracer dual-low-activity imaging.