FOLH1 and neoplasm: Co-injection of an excess of unlabeled PSMA-targeting ligand significantly reduced the tumor uptake for all compounds, proving uptake selectivity ([111In]In-PSMA-617 at 4 h p.i. 1.59 ± 0.03% ID/g vs. blocked 0.46 ± 0.26% ID/g (p < 0.01); [111In]In-22 at 4 h p.i. 1.23 ± 0.59% ID/g vs. blocked 0.27 ± 0.14% ID/g (p = 0.01); [111In]In-30 at 4 h p.i. 2.94 ± 0.36% ID/g vs. blocked 1.42 ± 0.14% ID/g (p < 0.01)).