61Cu-NODAGA-LM3 PET/CT for the Detection of Neuroendocrine Tumors (COPPER PET in NET)

Inclusion Criteria: * Written informed consent signed * \>18 years old patients of either gender * For women in child-bearing age: a negative pregnancy test is required * Histologically proven well-differentiated bronchopulmonary (typical or atypical carcinoid) or gastroenteropancreatic neuroendocrine tumors (NET) of all grade (including NET G3 with Ki-67 \<30 %) * Clinical indication to somatostatin receptor (SST) PET/CT imaging for either primary staging, restaging, patient selection to Peptide Receptor Radionuclide Therapy, treatment planning or treatment response assessment * Standard of care 68Ga-DOTATOC PET/CT performed or planned within max. 4 weeks prior or after IMP-administration, as clinically indicated * At least 3 lesions detected by the previous somatostatin receptor scan, or if 68Ga-DOTATOC PET/CT is negative, a positive NETest not older than 4 weeks should be available in 5 additional patients * Estimated eGFR (CKD-EPI) ≥ 45 mL/min * If applicable, the last regular somatostatin analogue injection should be administered 2 weeks +/- 1 week prior to SST PET scan for long acting release forms Exclusion Criteria: * Known hypersensitivity to 61Cu, to NODAGA, to LM3 or to any of the excipients of 61Cu-NODAGA-LM3 * 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 * Initiation or continuation of active anti-tumor treatment between 61Cu-NODAGA-LM3 and 68Ga-DOTATOC PET/CT, except continuation of long acting somatostatin analogues * Presence of active infection at screening or history of serious infection within the previous 6 weeks * Pregnant or breast-feeding women * History of somatic or psychiatric disease/condition that may interfere with the objectives and assessments of the study