A radioconjugate containing the bombesin (BBN) fragment BBN(7-14) comprised of the amino acid sequence of Gln-Trp-Ala-Val-Gly-His-Leu-Met-NH2, which targets the gastrin-releasing peptide receptor (GRPR), bound to aminocaproic acid (Aca), and linked by the macrocyclic chelating agent, 1,4,7-triazacyclononane-N,N',N''-triacetic acid (NOTA), to the radionuclide gallium (Ga) 68, with potential use in diagnostic imaging using positron emission tomography/computed tomography (PET/CT). Upon administration of gallium Ga 68-NOTA-Aca-BBN(7-14), the peptide moiety targets and binds to GRPR. Upon PET/CT, GRPR-expressing tumor cells can then be visualized. GRPR, also called bombesin receptor 2 (BB2), is a seven-transmembrane G protein-coupled receptor belonging to the bombesin receptor family. It is overexpressed in certain types of cancers.