PET Tracer Enables Noninvasive Measurement of Beta Cell Mass

Loss of these cells destabilizes glucose control and drives complications. Clinicians lack a noninvasive way to directly measure remaining beta cell mass, limiting treatment monitoring and trial end points. Researchers now report a quantitative imaging approach that aims to provide an objective readout of residual beta cell mass for disease staging and therapeutic evaluation.

The approach centers on [18F]FB(ePEG12)12-exendin-4, a glucagon-like peptide-1 (GLP-1) receptor–targeted PET tracer. Investigators at Kyoto University and Kyoto University Hospital administered the tracer intravenously and performed combined positron emission tomography (PET) and computed tomography (CT). The method is intended to visualize and quantify pancreatic uptake as a readout of residual beta cell mass in adults with type 1 diabetes.

In a prospective study at Kyoto University Hospital, adults with type 1 diabetes underwent PET/CT following tracer injection. The team quantified pancreatic tracer accumulation using standardized PET measures. Imaging data from these participants were compared with findings from participants without diabetes. The researchers also examined relationships between the imaging signal and clinical or laboratory indicators of glycemic control and insulin use.

Pancreatic uptake was lower in participants with type 1 diabetes than in those without diabetes. The imaging measure showed an inverse relationship with hemoglobin A1c and with total daily insulin dose, supporting its relevance to disease burden and treatment intensity. No serious side effects were observed among participants during the study.

According to the investigators, beta cell–targeted PET/CT could complement blood-based assessments by offering a direct, imaging-based measure of residual beta cell mass. Potential applications include refining disease staging, tracking longitudinal change, and providing objective end points for trials that aim to preserve or restore beta cells, particularly when function fluctuates independently of mass. The findings were published in Diabetes on March 12, 2026. Larger, longitudinal studies with more diverse participants are needed to confirm clinical utility.

"Our study was driven by a key gap in type 1 diabetes research and care," said Kentaro Sakaki, first author, Kyoto University. "We hope this approach can help fill that gap by providing an objective readout for therapeutic evaluation."

"Many decisions in type 1 diabetes treatment would benefit from a clearer picture of how much beta cell mass remains," said Takaaki Murakami, team leader, Kyoto University. "Our findings suggest that this tracer may provide a noninvasive, quantitative readout that could support disease staging and treatment monitoring."

Related Links
Koyoto University
Kyoto University Hospital