In the present preclinical study, we investigate the effect of stereoisomerism on the pharmacokinetics of [177Lu]Lu-rhPSMA-10.1 and [177Lu]Lu-rhPSMA-10.2 in healthy and PSMA-positive LNCaP-tumor bearing mice in order to identify the rhPSMA-10 isomer with the most favorable characteristics for radioligand therapy. This evidence concerns the gene FOLH1 and neoplasm.