Review paper
Diagnostic imaging of pancreatic neuroendocrine tumours, consider target radionuclide treatment

The incidence of pancreatic neuroendocrine tumors has been reported to be 4-12 per million per year. Well- differentiated tumours (NETWD, WHO I) are the majority. Most of this group consists of two groups: first insulinomas (secretor) and second, non-secretor tumors. NECLM (WHO type II) consists of tumours with signs of malignancy with lymph nodes involvement and liver tumour deposits most common. Poorly differentiated small cell cancers (NECHM, WHO III) are group with aggressive behaviour and very poor prognosis. Imaging modalities of diagnostic proceedings including: ultrasound, EUS, contrast enhanced CT, MRI, somatostatin receptor scintigraphy (SRS) and mIBG scintigraphy. EUS seems to be the most sensitive method to detect pancreato-duodenal tumours. Other anatomical imaging modalities like CT and MRI could be used to detect primary lesion within pancreas and more often used to staging approach. Small tumours and almost all insulinomas are not detected using routine SRS radiotracers. Imaging modalities and assessment of specific tumor markers offers high sensitivity in establishing the diagnosis and can also have prognostic significance. Most important single imaging technique in terms of initial identification is EUS but in terms of staging, CT, MRI or SRS should be used. Also both techniques anatomical and functional (scintigraphy) should be used to monitor the response on treatment. More recently, positron emission tomography (PET) scanning is being increasingly used for the localization of pancreatic GEP-NET due to develop new ⁶⁸Ga radiolabelled analogs of somatostatin receptors. The standard FDG PET is currently used in groups of high malignant tumours (NECHM, WHO type III). The therapeutic options for patients with progressive metastatic pancreatic NETs are often limited. Chemotherapy has limited efficacy, interferon on its own has no tumorcidal properties, also external radiotherapy has no efficacy. The limitations of all of these therapies, have led to the development of other tumour-targeting strategies, including radiolabelled ⁹⁰Y and ¹⁷⁷Lu somatostatin analogs. This type of treatment is used when there is no other therapeutic option. Treatment using β emitters is without significant toxicity and side effects.