Explore the Clinical Value of 68Ga-DOTANOC PET/CT and 18F-FDG PET/CT in Neuroendocrine Neoplasms

Inclusion Criteria: 1. sign written informed consent form 2. age ≥ 18 years 3. pathologically confirmed neuroendocrine, Ki67\>=10%; 4. ECOG 0-1; 5. No prior antitumor treatment with chemotherapy targeting regimens for neuroendocrine carcimomas, no more than 2 systematic treatment for neuroendocrine tumors; 6. Unresectable disease; 7. At least 1 measurable lesion (only 1 measurable lymph node lesion is excluded) (routine CT scan \>=20mm, spiral CT scan \>=10mm, no prior radiation to measurable lesions); 8. Predicted survival \>=3 months; 9. Negative serum or urine pregnant test within 7 days prior to randomization for child-bearing age women; 10. Sexually active males or females willing to practice contraception during the study until 30 days after end of study. Exclusion Criteria: 1. In the process of antitumor therapy with effective response; 2. Refuse to accept PET/CT; 3. Pregnant or nursing, or sexually active males or females refuse to practice contraception during the study until 30 days after end of study; 4. Person with no capacity (legally) or inappropriate to continue study treatment for ethics/medical reasons；