GRPR and neoplasm: Not surprisingly, [99mTc]Tc-N4-asp-[Bta8]MJ9 (p < 0.02) and [99mTc]Tc-N4-[Hse7]MJ9 (p < 0.01) showed the highest tumor-to-pancreas ratios at 1 h p.i. Nevertheless, it has to be mentioned that a comparison of in vivo data for [99mTc]Tc-Demobesin 4 and the four novel [99mTc]Tc-N4-conjugated MJ9 analogues must be drawn cautiously, as besides the different behavior of GRPR agonists and antagonists, different amounts of substance and animal strains were applied.