[68Ga]Ga-HBED-CC-exendin-4 and [68Ga]Ga-NOTA-exendin-4 PET/CT Imaging in the Same Group of Insulinoma Patients

[68Ga]Ga-HBED-CC-exendin-4 and [68Ga]Ga-NOTA-exendin-4 PET/CT Imaging in the Same Group of Insulinoma Patients

A Pilot Prospective Comparison of [68Ga]Ga-HBED-CC-exendin-4 and [68Ga]Ga-NOTA-exendin-4 PET/CT Imaging in the Same Group of Insulinoma Patients

Glucagon-like peptide-1 receptor (GLP-1R)-targeted PET imaging with 68Ga-labeled compounds is able to provide superior sensitivity and specificity to detect insulinoma, like the widely studied [68Ga]Ga-NOTA-exendin-4. This pilot study was prospectively designed to evaluate the early dynamic distribution of [68Ga]Ga-HBED-CC-exendin-4, a novel radiopharmaceutical targeting GLP-1R, which was compared with [68Ga]Ga-NOTA-exendin-4 in the same group of insulinoma patients.

Insulinoma is the most common cause of endogenous hyperinsulinemic hypoglycemia in adult patients without diabetes. The only curative treatment of an insulinoma is its surgical removal. Therefore, exact preoperative localization of the insulinoma is critical to planning the surgical intervention. MR imaging, CT, or endoscopic ultrasound is normally used to localize insulinomas. However, the small size of the tumors (often,1 cm) limits the sensitivity of these methods. In recent years, a new receptor-targeted imaging technique, glucagon-like peptide-1 receptor (GLP-1R) imaging, for detecting insulinoma has been established. GLP-1R is expressed on benign insulinoma cell surfaces with very high incidence (>90%) and density (8,133 dpm/mg of tissue). No other peptide receptor has been found to exhibit such high expression levels in insulinoma. [68Ga]Ga-HBED-CC-exendin-4, a novel radiopharmaceutical targeting GLP-1R, with the urea fragment of a conjugate that employs the HBED-CC chelator for labeling with 68Ga in order to In order to reduce the accumulation of radioactivity in the kidneys. This pilot study was prospectively designed to evaluate the early dynamic distribution of [68Ga]Ga-HBED-CC-exendin-4 compared with [68Ga]Ga-NOTA-exendin-4 in the same group of Insulinoma patients.

Patients of Insulinoma PET/CT imaging: In two consecutive days each patient underwent a 60-min dynamic PET/CT scan after intravenous administration of [68Ga]Ga-HBED-CC-exendin-4 and [68Ga]Ga-NOTA-exendin-4, respectively.

Intravenous injection of one dosage of 74-111 MBq (2-3 mCi) [68Ga]Ga-HBED-CC-exendin-4. Tracer doses of [68Ga]Ga-HBED-CC-exendin-4 will be used to image lesions of insulinoma by PET/CT.

Intravenous injection of one dosage of 74-111 MBq (2-3 mCi) [68Ga]Ga-NOTA-exendin-4. Tracer doses of [68Ga]Ga-NOTA-exendin-4 will be used to image lesions of insulinoma by PET/CT.

the early dynamic distribution (SUVmax in tumor lesions and SUVmean in normal organs at different time points) of [68Ga]Ga-HBED-CC-exendin-4 in comparison with [68Ga]Ga-NOTA-exendin-4 in the same group of insulinoma patients.

Sensitivity and Specificity of [68Ga]Ga-HBED-CC-exendin-4 for insulinoma in comparison with [68Ga]Ga-NOTA-exendin-4 PET/CT.

Inclusion Criteria: confirmed treated or untreated insulinoma patients; [68Ga]Ga-HBED-CC-exendin-4 and [68Ga]Ga-NOTA-exendin-4 PET/CT within two consecutive days; signed written consent. Exclusion Criteria: pregnancy; breastfeeding; known allergy against exendin-4; any medical condition that in the opinion of the investigator may significantly interfere with study compliance