Feasibility of Gd-Based prostate cancer targeted magnetic resonance agents using prostate specific membrane antigen.

The aim of this work was to evaluate Gd-FC705, a prostate-specific membrane antigen (PSMA)-targeted MRI contrast agent. The r1 and r2 relaxivities of Gd-FC705 are 5.94 mM-1s-1 and 17.77 mM-1s-1, respectively, in HSA solution (0.67 mM) at 3 T, which are higher than those of Gd-DOTA. Specific targeting efficacy was found with a 3-fold enhancement between PSMA-negative (PSMA-) and PSMA-positive (PSMA+) cells. The in vivo targeting and bio-distribution of Gd-FC705 were further confirmed using nude mice bearing PC3 human prostate cancer xenografts, which showed a 2-fold increase in the contrast-to-noise ratio (CNR) for PSMA+ tumors compared to PSMA- tumors 1 h post injection and a longer circulation time than Gd-DOTA. These results demonstrate that Gd-FC705 has great potential as a diagnostic agent for prostate cancer.