NODAGA-JR11 is a novel somatostatin receptor antagonist, while Gallium-68 DOTATATE is a typical somatostatin receptor agonist. This study is to evaluate the lesion detection ability of Gallium-68 NODAGA-JR11 for the diagnostic imaging of metastatic, well-differentiated neuroendocrine tumors using positron emission tomography / computed tomography (PET/CT).

The results will be compared between antagonist Gallium-68 NODAGA-JR11 and agonist Gallium-68 DOTATATE in the same group of patients.

Patients with histologically confirmed metastatic, well-differentiated neuroendocrine tumors will be recruited in this study.

Each patient received an intravenous injection of 68Ga-DOTATATE (40ug/150-200MBq) on the first day and 68Ga-NODAGA-JR11 (40ug/150-200MBq) on the second day. Whole-body PET/CT scans were performed at 40-60 min after injection on the same scanner. Physiologic normal-organ uptake, lesion numbers, and lesion uptake were compared.

Inclusion Criteria:

• • Written informed consent.

  • Patients of either gender, aged ≥ 18 years.

  • Histologically confirmed diagnosis of Metastatic, well-differentiated neuroendocrine tumor.

  • A diagnostic computed tomography (CT) or magnetic resonance imaging (MRI) of the tumor region within the previous 6 months prior to dosing day is available.

  • At least 1 measurable lesion based on RECIST v1.1.

  • Blood test results as follows (White blood cell: ≥ 3*10^9/L, Hemoglobin:

    ≥ 8.0 g/dL, Platelets: ≥ 50x10^9/L, Alanine aminotransferase / Aspartate aminotransferase / Alkaline phosphatase: ≤ 5 times upper limit od normal (ULN), Bilirubin: ≤ 3 times ULN)

  • Serum creatinine: within normal limits or < 120 μmol/L for patients aged 60 years or older.

  • Calculated Glomerular filtration rate (GFR) ≥ 45 mL/min.

Exclusion Criteria:

• • Known hypersensitivity to Gallium-68, to NODAGA, to JR11, to TATE or to any of the excipients of Gallium-68 NODAGA-JR11 or Gallium-68 DOTATATE.

  • Presence of active infection at screening or history of serious infection within the previous 6 weeks.
  • Therapeutic use of any somatostatin analog, including long-acting Sandostatin (within 28 days) and short-acting Sandostatin (within 2 days) prior to study imaging. If a patient is on long-acting Sandostatina, then a wash-out phase of 28 days is required before the injection of the study drug. If a patient is on short-acting Sandostatin, then a wash-out phase of 2 days is required before the injection of the study drug.
  • Any neuroendocrine tumor-specific treatment between antagonist and agonist scans.
  • 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.
  • Pregnant or breast-feeding women.
  • Current history of any malignancy other than neuroendocrine tumor; patients with a secondary tumor in remission of > 5 years can be included.
  • Any mental condition rendering the patient unable to understand the nature, scope and possible consequences of the study, and/or evidence of an uncooperative attitude.