Because of the COVID-19 pandemic, funding for the trial was terminated and attempts to find alternative sources of funding were to no avail.

The main goal is to study the correlation of pancreatic uptake of In-111-DTPA-exendin-4 (measured by ex vivo counting) with the beta cell mass determined in the pancreatic specimens obtained after surgery.

In order to fully characterize the highly promising tracer In-111-DTPA-exendin-4 in humans, quantitative SPECT imaging will be correlated to the ex vivo tracer distribution in patients undergoing pancreatectomy or a Whipple procedure. In vivo imaging will be combined with post-pancreatectomy (micro)autoradiography, measurement of In-111-DTPA-exendin-4 concentrations in the pancreas using a gamma counter and morphometric determination of the actual beta cell mass. By this means, the relation between tracer uptake and beta cell mass in non-diabetic patients and T2D patients will be established. These highly relevant data will allow the improvement of the interpretation of clinical quantitative SPECT data in subsequent studies in patients with T1D and T2D. In addition, high uptake has been observed in the duodenum/pyloric area in patients in an ongoing study. At this point in time, it remains unclear which cells are responsible for this uptake. It would be of great interest to identify the GLP-1R positive cells in order to better understand the physiological actions of GLP-1 agonists.

Inclusion Criteria:

• Scheduled for partial or complete pancreatectomy or Whipple procedure at Radboudumc

Exclusion Criteria:

• Resection that provides insufficient amount of tissue
• Previous treatment with synthetic Exendin (Exenatide, Byetta®) or Dipeptidyl- Peptidase IV inhibitors
• Breast feeding
• Pregnancy or the wish to become pregnant within 6 months
• Renal disease
• Liver disease
• Age < 18 years