Gallium-68 Labeled LM3 PET/CT in Neuroendocrine Tumors

Inclusion Criteria: * Written informed consent. * Patients of either gender, aged ≥ 18 years. * Histologically confirmed diagnosis of Metastatic, well-differentiated neuroendocrine tumor. * A diagnostic computed tomography (CT) or magnetic resonance imaging (MRI) of the tumor region within the previous 6 months prior to dosing day is available. * At least 1 measurable lesion based on RECIST v1.1. * Blood test results as follows (White blood cell: ≥ 3\*10\^9/L, Hemoglobin: ≥ 8.0 g/dL, Platelets: ≥ 50x10\^9/L, Alanine aminotransferase / Aspartate aminotransferase / Alkaline phosphatase: ≤ 5 times upper limit od normal (ULN), Bilirubin: ≤ 3 times ULN) * Serum creatinine: within normal limits or \< 120 μmol/L for patients aged 60 years or older. * Calculated Glomerular filtration rate (GFR) ≥ 45 mL/min. Exclusion Criteria: * Known hypersensitivity to Gallium-68, to NODAGA, to DOTA, to LM3, to TATE or to any of the excipients of Gallium-68 DOTA-LM3, Gallium-68 NODAGA-LM3 or Gallium-68 DOTATATE. * Presence of active infection at screening or history of serious infection within the previous 6 weeks. * Therapeutic use of any somatostatin analog, including long-acting Sandostatin (within 28 days) and short-acting Sandostatin (within 2 days) prior to study imaging. If a patient is on long-acting Sandostatina, then a wash-out phase of 28 days is required before the injection of the study drug. If a patient is on short-acting Sandostatin, then a wash-out phase of 2 days is required before the injection of the study drug. * Any neuroendocrine tumor-specific treatment between antagonist and agonist scans. * Prior or planned administration of a radiopharmaceutical within 8 half-lives of the radionuclide used on such radiopharmaceutical including at any time during the current study. * Pregnant or breast-feeding women. * Current history of any malignancy other than neuroendocrine tumor; patients with a secondary tumor in remission of \> 5 years can be included. * Any mental condition rendering the patient unable to understand the nature, scope and possible consequences of the study, and/or evidence of an uncooperative attitude.