• Change from baseline to 6 months in goiter size by recent CT scan. [ Time Frame: Duration of study ] [ Designated as safety issue: No ]
  

• Change from baseline to 6 months in SCAT. [ Time Frame: Duration of study ] [ Designated as safety issue: No ]
  

Inclusion Criteria:

• Clinical diagnosis of multinodular goiter, judged clinically and by ultrasound at Screening to be at least 40 mL, but less than or equal to 110 mL in size.
• Potential patients need to be clinically free of thyroid cancer as determined by their health provider.
• Women of childbearing potential must have a negative pregnancy test at Screening.
• Routine blood laboratory values within normal range at Screening, as determined by central lab.
• Committed to follow all protocol-required study procedures as evidenced by providing written informed consent within 14 days prior to Visit 1.

Exclusion Criteria:

• Potential candidates that have a history of thyroid cancer, signs or symptoms of thyroid cancer, a history of head or neck irradiation, or a partial or near total thyroidectomy.
• Within the past 45 days, use of propylthiouracil, methimazole or thyroxine, vitamins or supplements containing kelp or iodine, medications that significantly affect iodine handling such as high dose corticosteroids, high dose diuretics, or lithium.
• Patient has currently or within the past 60 days used retinoic acid.
• Use of amiodarone within the prior 2 years.
• Received iodine-containing contrast agent within the past 3 months.
• Patients with conditions in which use of beta-blockers are medically contraindicated, such as recently active asthma or clinically significant chronic obstructive pulmonary disease.
• Within the past 5 years have a history of malignancy, other than squamous or basal cell carcinoma of the skin or carcinoma in situ of the cervix.
• Prior MI, stroke within 6 months; atrial fibrillation or clinically significant arrhythmia within 6 months.
• A concurrent major medical disorder (e.g., documented cardiac disease, debilitating cardiopulmonary disease, advanced renal failure, advanced liver disease, advanced pulmonary disease, or advanced cerebral vascular disorder) that may have an impact on the capability of the patient to adequately comply with the requirements of this study.
• Women who are pregnant or lactating.
• A recent history of alcoholism, drug abuse or other disorder that might affect compliance with the protocol.
• Patients on anticoagulants except for aspirin.
• Patients known to be human immunodeficiency virus (HIV) antibody positive or hepatitis B antigen positive.
• Patients who have received 131I in the past, and have had a lifetime exposure of radioiodine.