For example, Tse et al. conjugated iron oxide nanoparticles (NPs) with the J591 antibody for targeting the prostate-specific membrane antigen (PSMA), showing enhanced contrast accumulation in prostate cancer in preclinical MRI [19]; meanwhile, Zhu et al. showed similar results with polypeptide-labeled SPIONSs [20]. Here, FOLH1 is linked to prostate cancer.