Radioguided surgery of focal congenital hyperinsulinism using Ga-68 Exendin: Proof of concept

Introduction: Congenital hyperinsulinism (CHI) is associated with high morbidity and if untreated can cause death. Surgery is the only curative option. However intraoperative exact localization of a small intrapancreatic beta cell mass producing insulin is often a challenge. With this background we investigated a new radioguided surgical (RGS) approach to localize the focus with the help of ⁶⁸Ga Exendin

Methods: 12 CHI patients (age 2.4 - 43.3 months) were injected with approx. 25 MBq of ⁶⁸Ga Exendin intravenously after standard surgical preparation of the pancreas. Detection rate of hand held positron- and gamma-radiation probe for intrapancreatic localization of the focus was evaluated. In addition, duration of radioguided surgery (defined as the time from first incision until the final sutures has been placed and abdomen closed) was compared with data of patients operated without RGS. Efficacy of the approach was determined by long term (mean 3 years) follow-up data on blood sugar control retrieved from patient´s medical files.

Results: Hand held probe detected 11/12 (92%) pre-oparatively localized foci on ⁶⁸Ga Exendin PET. Only one lesion in the vicinity of left kidney could not be detected. Histopathology confirmed all lesions as CHI foci. The signal-to-noise-ratio of the focus was > 10 times compared to normal pancreatic tissue. Radioguided surgery resulted in reduction of duration of surgery from median 5.5 (CI 4 to 6.7) to 4.7 (CI 3.5 to 6.7) hours. All patients remained euglycemic for a median follow-up period of 3 years (range 2 to 4.5).

Conclusions: In this explorative proof of concept analysis, we demonstrated a high precision of ⁶⁸Ga Exendin for intraoperative localization of intrapancreatic CHI foci. By directing the surgeons to the correct position, RGS can potentially decrease surgery duration by approximately 45 minutes, thereby reducing the risk of perioperative complications.