Inclusion Criteria:

• Patients must have received first line standard chemotherapy and/or radiation therapy for neuroendocrine malignancy in the past and failed the therapy.
• Patients must have evidence of residual multifocal active tumor.
• All patients must sign an informed consent indicating the awareness of the investigational nature of the studies involved.
• All patients must have a Karnofsky performance status of at least 60.
• Patients must be greater than 18 years of age.
• Patients must have measurable and/or followable disease based on either clinical or radiologic exam.
• Sensitivity to Indium-111 pentetreotide or any of its components is an absolute contraindication to participation in this trial.
• An absolute contraindication is pregnancy as evidenced by the clinical condition, a positive pregnancy test (B-HCG or pelvic ultrasound).
• If patients have received prior radionuclide therapy of the same product, there must be documented response to that therapy and/or residual active stable disease.

Exclusion Criteria:

• Karnofsky performance status of 50 or less.
• Patients who are unable to give informed consent.
• Patients under 18 years of age. There will be no upper age discrimination.
• Patients who are pregnant or those potentially pregnant subjects not willing to practice effective contraceptive techniques during the study period.
• Patients with renal insufficiency as defined by a calculated creatinine clearance (based on age, weight and serum creatinine) of 39.9 ml/min or less.