FOLH1 and neoplasm: In addition, 99mTc-22, the most hydrophilic radioligand in the tricarbonyl series, had high, specific and retained tumor uptake in the PSMA+ PC3 PIP tumor (28.31 ± 4.38, 28.05 ± 2.04, 26.29 ± 7.45, 23.22 ± 6.02 % IA/g, at 0.5, 1, 2 and 5 h p.i. respectively).