Figure 1a,b show the ProCA1.GRPR distribution and GRPR expression in the explanted tumor tissue from two different mouse PCa cell lines, PC3 and H441. The corresponding MRI images (Figure 1d,e) illustrate the specific binding of the contrast agent by a higher signal intensity after contrast agent administration by tail vein injection, with an eight times lower clinical injection dose (5 mM) [92]. Here, GRPR is linked to neoplasm.