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Current radiolabeled gastrin-releasing peptide receptor (GRPR) ligands usually suffer from high accumulation in GRPR-positive organs (pancreas, stomach), limiting tumor-to-background contrast in the abdomen. In novel N₄-bombesin derivatives this was addressed by substitutions at the Gln⁷-Trp⁸ site within the MJ9 peptide (<i>H</i>-Pip⁵-phe⁶-Gln⁷-Trp⁸-Ala⁹-Val¹⁰-Gly¹¹-His¹²-Sta¹³-Leu¹⁴-NH₂) either by homoserine (Hse⁷), <i>β</i>-(3-benzothienyl) alanine (Bta⁸) or <i>α</i>-methyl tryptophan (<i>α</i>-Me-Trp⁸), with the aim of optimizing pharmacokinetics. We prepared and characterized the peptide conjugates 6-carboxy-1,4,8,11-tetraazaundecane (N₄)-asp-MJ9, N₄-asp-[Bta⁸]MJ9, N₄-[Hse⁷]MJ9 and N₄-[α-Me-Trp⁸]MJ9, and evaluated these compounds in vitro (GRPR affinity via <i>IC</i>_50,inverse; internalization; lipophilicity via log<i>D</i>_7.4) and in vivo (biodistribution and <i>μ</i>SPECT/CT studies at 1 h post injection (p.i.) in PC-3 tumor-bearing CB17-SCID mice). ^99mTc-labeling resulted in radiochemical yields (RCYs) > 95%. All ^99mTc-labeled MJ9 analogues showed comparable or higher GRPR affinity than the external reference [^99mTc]Tc-Demobesin 4. Receptor-bound fractions were noticeably higher than that of the reference. Despite a slightly enhanced lipophilicity, all novel MJ9 derivatives revealed improved in vivo pharmacokinetics compared to the reference. The Bta⁸-modified ligand revealed the most favorable tumor-to-abdomen contrast at 1 h p.i. Substitutions at the Gln⁷-Trp⁸ site within GRPR ligands hold great potential to modify pharmacokinetics for improved imaging.