Inclusion Criteria:  Histologically proven well differentiated neuroendocrine tumor (NET) of gastrointestinal or pancreatic origin (GEP). Patients are progressive after treatment with cold somatostatin analog (within 12 months according to RECIST), or as soon as the diagnosis is made in case of hepatic invasion > 50% without waiting for tumour progression Patient has received 4 standard of care LUTATHERA® cycles Liver Metastatic disease dominant or exclusive and assessable by RECIST 1.1, and not amenable to surgical resection after the last cycle ECOG performance status 0-2 Adequate kidney and liver function: creatinine clearance ≥ 50 mL/min, ALT/AST ≤ 2,5x the upper limit of normal With no evidence of hematologic alteration after 4 LUTATHERA® cycles: hemoglobin ≥ 8 g/dL, neutrophils ≥ 1500/ mm3, platelets ≥ 100.000/mm3 Age ≥ 18 years, no superior limit Contraception required in pre-menopausal female (Intrauterine device, Progestin Pills, Combined Oral Contraceptives, Monthly Injectables, Progestin Injectables, Combined Patch, Combined Vaginal Ring, Female Sterilization, Vasectomy, Implants) and men for at least 6 months after the last LUTATHERA ® injection. Patient´s signed written informed consent Patient affiliated to a social security system  Exclusion Criteria:  Patients with complete response defined by the absence of lesion according to RECIST 1.1 realized during morphological imaging at inclusion (chest-abdomen-pelvis CT scan and hepatic MRI) No residual uptake according to standard 177-Lu scintigraphy performed in the clinical routine 24 hours after each LUTATHERA IV treatment Carcinoid heart disease (LVEF < 40%) Dominant or threatening extrahepatic metastases or that may affect vital prognosis Contraindications to intra-hepatic arterial infusion (coagulation disorders, portal thrombosis, intra-hepatic biliary tract dilatation, digestive or biliary anastomosis or fistula, cirrhosis (Child Pugh B8 or C…) Serum albumin <30 g/L unless prothrombin time is within the normal range. Heart failure, myocardial infarction, stroke, uncontrolled arterial hypertension under optimal treatment (≥ 160/95 mmHg), pulmonary embolism or revascularization procedure, unstable angina pectoris, uncontrolled cardiac arrhythmia, and clinically significant bradycardia during the last 12 months. Individuals under legal protection or unable of giving their informed consent Pregnancy or breast feeding Currently participating to another clinical research protocol Individuals under legal protection or unable of giving their informed consent MRI scan contraindicated LUTATHERA® contraindicated or toxicity during one of the IV administrations leading to a reduction or cancellation of the following dose