Radioguided surgery with β^- radiation in pancreatic Neuroendocrine Tumors: a feasibility study

The possibility to use β^- decaying isotopes for radioguided surgery (RGS) has been recently proposed, and first promising tests on ex-vivo samples of Meningioma and intestinal Neuroendocrine Tumor (NET) have been published. This paper reports a study of the uptake of ⁶⁸Ga-DOTATOC in pancreatic NETs (pNETs) in order to assess the feasibility of a new RGS approach using ⁹⁰Y-DOTATOC. Tumor and healthy pancreas uptakes were estimated from ⁶⁸Ga-DOTATOC PET/CT scans of 30 patients with pNETs. From the obtained SUVs (Standardised Uptake Value) and TNRs (Tumor Non tumor Ratio), an analysis algorithm relying on a Monte Carlo simulation of the detector has been applied to evaluate the performances of the proposed technique. Almost all considered patients resulted to be compatible with the application of β^--RGS assuming to administer 1.5 MBq/kg of activity of ⁹⁰Y-DOTATOC 24 h before surgery, and a sampling time of few seconds. In just 2 cases the technique would have required a mildly increased amount of activity or of sampling time. Despite a high physiological uptake of ⁶⁸Ga-DOTATOC in the healthy pancreas, the proposed RGS technique promises to be effective. This approach allows RGS to find application also in pancreatic diseases, where traditional techniques are not viable.