Positron emission tomography/computed tomography (PET/CT) is an advanced nuclear medicine scan. This technology allows precise and early cancer to be visualized and measured on whole body images. Patients with Neuro-Endocrine tumors (NETs), require specialized molecular imaging to stage, re-stage and assess eligibility and response to therapy. 68Ga-DOTATATE is a nuclear medicine imaging agent that is not yet approved by Health Canada but used extensively throughout the world. The Ki-67 index, a marker of cell proliferation in NETs, is one of the most important prognostic factors in this disease. The objective of this study is to evaluate if the maximal standard uptake value (SUVmax) on PET/CT in NETs inversely correlates with Ki-67 score on initial biopsy. If this hypothesized correlation between SUV and Ki-67 score is reproduced, then DOTATATE would serve as a non-invasive method to assess cellular proliferation and therefore prognosis of these patients.

Inclusion Criteria:

• Known or suspected somatostatin receptor positive tumor such as: neuroendocrine tumor (carcinoid, gastro-entero-pancreatic neuroendocrine tumors, etc); pheochromocytoma; neuroblastoma; medulloblastoma; ectopic Cushing syndrome/non-pituitary ACTH elevation; tumor-induced osteomalacia. Supporting evidence may include MRI, CT, biochemical markers, and/or pathology report.
• Previous diagnosis of NET with Ki-67 index available or soon to be obtained.
• ECOG performance status 0 - 3, inclusive.
• 18 years or older and able to understand and provide written informed consent
• Patients must be able to tolerate the physical/logistical requirements of a PET/CT scan including lying supine for up to 45 minutes with the arms above the head and tolerating intravenous cannulation for injection of the study drug

Exclusion Criteria:

• Medically unstable patients (e.g. acute cardiac or respiratory distress or hypotensive, etc.)
• Patients who exceed the safe weight limit or bore of the PET/CT bed
• Patients who are claustrophobic or pregnant