FOLH1 and neoplasm: To demonstrate that uptake was PSMA-mediated, five mice were co-injected with [18F]RPS-040 and 2-phosphonomethylpentanedioic acid (2-PMPA), a potent PSMA inhibitor [32], and sacrificed at 1 h p.i. At this time point, tumor uptake decreased from 12.69 ± 1.56 %ID/g (n = 5) in the unblocked set of mice to 1.75 ± 0.15 %ID/g (n = 5) in the set co-administered with 2-PMPA.