Inclusion Criteria:  Able to provide written informed consent Age greater than or equal to 19 years Biopsy-proven, well-differentiated grade 1 - 3 NET Gastroenteropancreatic tumors (e.g. carcinoids, gastrinoma, insulinoma, glucagonoma, VIPoma, etc.), functioning and non-functioning Sympathoadrenal system tumors (phaeochromocytoma, paraganglioma) Pulmonary NET, functioning and non-functioning Easter Cooperative Oncology Group (ECOG) ≤ 2 Ki67 ≤ 55% Progressive disease demonstrated by RECIST 1.1 criteria within the 6 months preceding the study. Patients with other evidence of progressive disease that is not demonstrated on CT (like rising biomarkers) may be included, at the discretion of the Tumour Review Board. If response to other treatments is considered adequate according to other criteria, the Tumour Review Board may consider excluding the patient from participation in the study. Tumour Review Board confirmation of suitability to proceed to PRRT treatment and enrollment in this trial. Positive PET SSR imaging (Krenning score 2 or higher) in previous 6 months (68Ga-DOTATOC, 68Ga-DOTATATE, 18F-AmBF3-TATE). If PET SSR imaging is not available 111In-penetreotide scintigraphy (Octreotide scan) is acceptable. Adequate laboratory parameters within two weeks of enrollment  Kidneys  Serum creatinine ≤ 150 µmol/L GFR ≥ 40 ml/min (using plasma clearance values)  Marrow  Hemoglobin ≥ 80 g/L WBC ≥ 2 x 109/L Platelets ≥ 75 x 109/L Liver Total bilirubin ≤ 3 x upper limit of normal (ULN) ALT ≤ 3 x ULN or ≤ 5 x ULN if liver metastasis Alkaline phosphatase ≤ 3 x ULN or ≤ 5 x ULN if liver metastasis Subject's ability to comply with scheduled visits, treatment plans, laboratory tests, imaging tests, and other procedures required as detailed in the protocol.  Exclusion Criteria:  Women and men of childbearing potential Procreation  Women: pregnancy test done before enrollment before each treatment cycle. And subject must use adequate contraception for the duration of therapy, be surgically sterile, or post-menopausal. Men: must be surgically sterile or use adequate contraception for the duration of the therapy. Patient with another non-cutaneous (excluding melanoma) active cancer requiring therapeutic intervention. Curative medical or surgical treatment, local liver embolization, or debulking are appropriate options. Life expectancy is less than 12 weeks. Radiotherapy to target lesions ≤ 12 weeks ago or to more than 25% of bone marrow. PRRT at any time prior to randomization in this study. Systemic therapy (chemotherapy) within 4 weeks of PRRT and other locoregional therapies (radioisotope, embolization) within 12 weeks prior to enrollment. Ongoing use of somatostatin analogs for control of symptoms is allowed. Known brain metastases (unless treated and stable for more than 3 months). Co-morbidities that could, in the opinion of the PI, interfere with safe delivery of PRRT (like urinary incontinence, psychiatric illness), uncontrolled congestive heart failure (NYHA II, III, IV) Breastfeeding (if patients elect to discontinue breast feeding, they can participate in the trial).