One approach aimed at improving SPECT imaging or therapy of PCa by using a 99mTc-labeled heterobivalent agent based on the GRPR-specific Lys3-bombesin and TAT49–57, serving as a cell-penetrating peptide intended to internalize GRPR-bound dimer into the target cell [94,95] (23, Figure 8). Here, GRPR is linked to posterior cortical atrophy.