FOLH1 and brain neoplasm: Furthermore, there are no meta-analyses about the diagnostic performance of PET with other emerging tracers for evaluation of brain tumors, such as radiolabelled prostate-specific membrane antigen (PSMA) [36] or fluorine-18 fluciclovine (18F-FACBC) [37], or with extensively studied tracers such as α-[11C]methyl-L-tryptophan [38].