Vees et al. [46] in a multicentre retrospective study, evaluated 20 patients divided into two different groups with biochemical recurrence or suspected residual tumour after RP with a PSA serum level less than 1.0 ng/mL (range 0.11–0.73 ng/mL): in the first group they used 18F-Ch PET-CT to detect local recurrence whereas in the second group they used 11C-acetate PET-CT. This evidence concerns the gene KLK3 and neoplasm.