[18F]FDG and [68Ga]Ga-PSMA dual-tracer total-body PET/CT and PET/MR in patients with prostate cancer

Prostate cancer (PCa) is a heterogeneous disease and prevalent malignancy in men, necessitating accurate imaging techniques to facilitate effective diagnosis and management. Recent evidence has demonstrated that [18F]fluorodeoxyglucose ([18F]FDG) and prostate-specific membrane antigen (PSMA)-targeted PET tracers positron emission tomography/computed tomography (PET/CT) imaging can provide complementary biological information, thereby improving diagnostic accuracy and the assessment of lesion heterogeneity in patients with PCa. However, optimal protocols for PSMA/FDG dual-tracer PET/CT and PET/magnetic resonance (PET/MR) imaging remain under investigation. Total-body PET/ CT, with its enhanced sensitivity, enables imaging with low tracer activity and facilitates the development of novel dual-tracer PET/CT imaging protocols. PET/MR offers additional valuable information for the diagnosis and local staging of PCa due to its superior soft tissue resolution and multiparametric capabilities. Thanks to the longer MR acquisition time, it is possible to perform low-activity radiotracer PET imaging with the same long-time MR acquisition. Additionally, advancements in time-of-flight technology and the improved sensitivity of PET systems further make low-activity radiotracer PET/MR imaging clinically feasible. Given that expertise in total-body PET/CT imaging technology and access to PET/MR scanners are limited to a relatively small number of institutions worldwide, this review provides clinical exploration to optimize workflows for [68Ga]Ga-PSMA-11 and [18F]FDG dual-tracer PET/CT and PET/MR imaging, with a focus on radiation dose reduction through dual-low-activity-tracer imaging protocols.