TAC1 and neoplasm: In past few years, [99mTc]Tc-HYNIC has been the most commonly used core for the conventional radiolabeling of bioactive peptides for tumor imaging such as RGD peptides [38,39], α-MSH peptide analogues [40,41], bombesin analogues [42,43], substance P analogues [44], or glucagon-like peptide analogues [45].