Despite binding to PSMA by a different mechanism, when measured in the same cell line (DU145-PMSA), the affinity of 68Ga-THP-mal-J591c-scFv for PSMA is comparable to that of 68Ga-HBED-CC-PSMA and 68Ga-DOTA-PSMA [15], which are both examples of the new generation of small molecule-based tracers, used clinically for prostate cancer imaging, and which bind to the enzymatically active peptidase site of PSMA [3, 14]. Here, FOLH1 is linked to prostate cancer.