Inclusion Criteria:

Patients will enter one of two study arms depending on their type of neuroendocrine tumor.

Arm P patients must:

- Have a biochemical or histopathological diagnosis of either adrenal pheochromocytoma
or extra-adrenal paraganglioma (biochemical diagnosis includes plasma-free
metanephrines and 24-hour urine test for catecholamines/metanephrines)

- Disease is metastatic or has recurred following surgery

- Have a CT scan performed (for later measurement of disease volume by the core lab)
within 90 days of the administration of study drug without any interventions between
CT and iobenguane I 131 imaging.

Arm C patients must:

- Have a histopathological diagnosis of carcinoid, or by plasma chromogranin A (CgA)
and 24-hour urine test for 5-hydroxyindole-acetic-acid (5HIAA)

- Disease is metastatic or has recurred following surgery

- Have a CT scan performed (for the later measurement of disease volume by the core
lab) within 90 days of the administration of study drug without any interventions
between CT and iobenguane I 131 imaging.

All patients in Arm P and Arm C must also meet each of the following inclusion criteria:

- Provide written informed consent and are willing to comply with protocol requirements

- Are at least 18 years of age

- If female, then not of childbearing potential as documented by history (e.g., tubal
ligation or hysterectomy) or is post menopausal with a minimum 1 year without menses

- If female of childbearing potential, has a negative serum HCG pregnancy test within
24 hours prior to receiving iobenguane I 131

- If female of childbearing potential, agrees to use an acceptable form of birth
control, defined as abstinence or use of IUD, oral contraceptive, barrier and
spermicide, or hormonal implant, throughout the study period

Exclusion Criteria:

- • Females who are nursing

- Documented history of significant allergy that required medical intervention to
shellfish, X-ray contrast media , iodine/iodides, or iobenguane

- Administered a radioisotope within 5 effective half-lives of that radioisotope
prior to study enrollment

- Karnofsky performance status is < 60

- Serum creatinine > 2.0 mg/dL

- Total bilirubin > 1.5 times the upper limit of normal

- AST/SGOT or ALT/SGPT > 3 times the upper limit of normal

- Has received an investigational compound and/or medical device within 30 days
before admission into this study

- Has any medical condition or other circumstances which would significantly
decrease the chances of obtaining reliable data, achieving study objectives, or
completing the study and/or post dose follow-up examinations

- Is determined by the Investigator that the patient is clinically unsuitable for
the study

- Has received a medication which inhibits uptake of iobenguane I 131 within 2
weeks prior to the administration of study drug. Patients must not have taken
tricyclic antidepressants or related drugs within 6 weeks prior to enrollment.