FOLH1 and neoplasm: Finally, a head-to-head comparison between [68Ga]Ga-PSMA-11 and [18F]AlF-PSMA-11 was performed on three tumour-free subjects already (Li et al. 2022), and an extensive head-to-head validation performed on four PCa patients was carried out in this study, but a further comparison focused on tumour was more meaningful in exploring the clinical advantages of [18F]AlF-PSMA-11 PET.