Controversies in NEN: An ENETS position statement on the interchangeability of somatostatin receptor PET tracers.

Molecular imaging of the somatostatin receptor (SSTR) plays a key role in the management of patients with neuroendocrine neoplasms in general, and neuroendocrine tumours in particular. Over the last 2 decades, gallium-68 labelled somatostatin analogues have revolutionised SSTR imaging through the advent of SSTR positron emission tomography (PET), leading to better staging and theranostic imaging. Recent advances in the development of PET SSTR tracers continue to change the field, with novel tracers labelled with different radionuclides such as fluorine-18 and copper-64, or based on new antagonist vector molecules. The advent of these innovations generates questions, such as which tracers can be used in clinical practice, how to compare scans performed with different tracers, or can antagonists be used to select patients for peptide receptor radionuclide therapy? This 'controversy paper' from the European Neuroendocrine Tumor Society provides an overview of the relevant evidence to answer these questions, and provides guidance to clinicians and nuclear medicine physicians for contemporary use of SSTR PET.