• Maximum Tolerated Dose of 67Cu-SARTATE [ Time Frame: 6 weeks ]
  MDT as determined by cohort observations of DLTs
• Safety and tolerability of Cu-67 SARTATE using CTCAE version 4.03 [ Time Frame: Up to 12 months ]
  Safety will be assessed via vital signs, pathology tests (hematology, biochemistry, urinalysis, coagulation), physical examinations, ECGs and spontaneous AE reporting.
• Safety and tolerability of Cu-64 SARTATE using CTCAE version 4.03 [ Time Frame: Up to 12 months ]
  Safety will be assessed via vital signs, pathology tests (hematology, biochemistry, urinalysis, coagulation), physical examinations, ECGs and spontaneous AE reporting.
• Objective response and best response [ Time Frame: 6 to 8 weeks post final therapy ]
  For patients receiving at least 1 administration of 67Cu-SARTATE, as assessed by INRC.

• Maximum Tolerated Dose of 67Cu-SARTATE [ Time Frame: 6 weeks ]
  MDT as determined by cohort observations of DLTs
• Safety and tolerability of Cu-67 SARTATE using CTCAE version 4.03 [ Time Frame: Up to 12 months ]
  Safety will be assessed via vital signs, pathology tests (hematology, biochemistry, urinalysis, coagulation), physical examinations, ECGs and spontaneous AE reporting.
• Safety and tolerability of Cu-64 SARTATE using CTCAE version 4.03 [ Time Frame: Up to 12 months ]
  Safety will be assessed via vital signs, pathology tests (hematology, biochemistry, urinalysis, coagulation), physical examinations, ECGs and spontaneous AE reporting.
• Objective response rate [ Time Frame: 6 to 8 weeks post final therapy ]
  For patients receiving at least 1 administration of 67Cu-SARTATE, as assessed by INRC.

• Drug: 67Cu-SARTATE
  67Cu-labelled MeCOSar-Tyr3-octreotate
  Other Name: Cu-67 SARTATE, copper 67 SARTATE
• Drug: 64Cu-SARTATE
  64Cu-labelled MeCOSar-Tyr3-octreotate
  Other Name: Cu-64 SARTATE, copper 64 SARTATE

Inclusion Criteria:

1. Participant is able and willing to provide informed consent (≥18 years), or informed consent is obtained by the parent or legal guardian for minor participants, with the minor providing age appropriate assent, according to local law and regulations;
2. Life expectancy ≥ 12 weeks;
3. Known high-risk neuroblastoma with failure to respond to standard therapy (combination chemotherapy with or without radiation and surgery), or development of PD at any time;
4. Adequate recovery from acute toxic effects of any prior therapy, as deemed by the Investigator or treating Sub-Investigator;
5. Adequate liver function as defined by the following laboratory values obtained within 28 days prior to administration of 64Cu-SARTATE: Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) < 3.0 x upper limit of normal (ULN);
6. Adequate renal function;
7. Adequate laboratory parameters: Absolute neutrophil count > 1.0 x 109/L; Platelet count > 50 x 109/L; Serum bilirubin <1.5 x ULN;
8. Karnofsky or Lansky performance status ≥50;
9. All participants must have a hematopoietic stem cell product available (minimum CD34+ cell dose is ≥2 x 106 cells/kg);
10. Sexually active participants of reproductive potential must practice an effective method of birth control while participating on this study, to avoid possible damage to the fetus. Abstinence is considered acceptable;
11. 64Cu-SARTATE uptake on the 4 hour scan (SUVmax) of any lesion equal to or higher than that of the liver in order to move on to the therapy phase of the study.

Exclusion Criteria:

1. Participants with disease of any major organ system that would compromise their ability to tolerate therapy, as deemed by the Investigator or treating Sub-Investigator;
2. Any other active malignancy, or a history of prior malignancy within the past 3 years;
3. History of cardiac failure as evidenced by: dyspnea at rest, exercise intolerance, oxygen requirement, clinically significant cardiac dysfunction;
4. Planned administration of chemotherapy, anti-cancer cytokine therapy, immunotherapy, radiotherapy or other investigational agents within 2 weeks prior to the administration of 64Cu-SARTATE and 4 weeks prior to the administration of 67Cu-SARTATE;
5. Administration of therapeutic dose of 131I-MIBG within 8 weeks prior to the administration of 64Cu-SARTATE;
6. EBRT to both kidneys or a single functioning kidney within 12 months prior to the administration of 64Cu-SARTATE;
7. Administration of any investigational agents within 28 days prior to administration of 64Cu-SARTATE;
8. Treatment with long acting somatostatin analogues (administered within 28 days prior to the administration of 64Cu-SARTATE), or short acting somatostatin analogues (administered within 24 hours prior to the administration of 64Cu-SARTATE);
9. Known sensitivity or allergy to somatostatin analogues;
10. Previous PRRT;
11. Female participants who are pregnant or lactating;
12. Participants who are on hemodialysis;
13. QTc interval ≥ 0.45 seconds as measured by Screening ECG;
14. Participants with uncontrolled infection(s);
15. Any medical condition which the Investigator feels may interfere with the procedures or evaluations of the study;
16. Participants 12 month and younger will be excluded from cohorts where the planned single or cumulative administered activity is modelled to deliver a radiation dose to the marrow that exceeds 2 Gy.