After 24 h, the PC-3 PIP tumor retentionof [177Lu]Lu-P17 and [177Lu]Lu-P18 decreasedminimally to 10.5 ± 0.3% and 17.7 ± 3.2% IA/g, respectively,while [177Lu]Lu-PSMA-617 retained 22.3 ± 3.5% IA/g.The tumor-to-blood ratio reached high values as soon as 1 h p.i. andfurther increased to 619 and 2351 at 24 p.i. for [177Lu]Lu-P17and [177Lu]Lu-P18, respectively, compared to 1306 for [177Lu]Lu-PSMA-617. Here, FOLH1 is linked to neoplasm.