Synthesis and Preliminary Biological Evaluation of ⁶⁸Ga-labeled GIPR Targeting Probe

Glucose-dependent insulinotropic polypeptide receptor (GIPR) is one of the important targets of neuroendocrine tumors (NETs). In this study, a novel GIPR targeting probe ⁶⁸Ga-DOTA-GIP(1-30)-F-02 was constructed through the module for automatic labeling. The labeling yield, radiochemical purity, and in vitro stability of this probe were investigated. The biodistribution in normal ICR mice and Micro-PET/CT imaging of PC12-hGIP tumor-bearing mouse models were studied. The results showed that the automatic method for ⁶⁸Ga-DOTA-GIP(1-30)-F-02 preparation was simple and convenient with a good radiochemical yield of (65.32±1.57)%, high radiochemical purity (>99%), and good in vitro stability. The results of biodistribution showed low uptakes of ⁶⁸Ga-DOTA-GIP(1-30)-F-02 in normal tissues, mainly excreted through the renal urinary system. Micro-PET/CT imaging showed the uptake at the tumor site reached (6.51±1.03)%ID/g at 60 min post-injection which indicates good tumor imaging potentiality. The feasibility and specificity of the probe for GIPR-targeted imaging of neuroendocrine tumors were preliminarily demonstrated.