Iodine I 131 in Treating Patients With Thyroid Cancer

DISEASE CHARACTERISTICS: * Diagnosis of thyroid cancer * Measurable disease by CT scan or nuclear medicine imaging * Eligible, by standard of care criteria, for iodine I 131 therapy PATIENT CHARACTERISTICS: * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective non-barrier method contraception (e.g., combined or progesterone-only oral contraceptive pill, intrauterine device, depot progesterone, or stable relationship with a partner who has had a vasectomy) * No other malignancy within the past 5 years except squamous cell or basal cell carcinoma of the skin * No nonthyroidal conditions known to affect iodine I 131 uptake (e.g., New York Heart Association class III or IV congestive heart failure or renal failure) * No alcoholism or drug abuse within the past 2 years * No severe emotional, behavioral, or psychiatric problems that would preclude study compliance (e.g., severe claustrophobia) PRIOR CONCURRENT THERAPY: * No intravenous water-soluble radiographic contrast within the past 4 weeks * No iodinated contrast agent within the past 3 months * No concurrent drugs that may affect thyroid or renal function (e.g., renal drugs, lithium, amiodarone, other iodine-containing medication, or corticosteroids) * No other concurrent investigational drugs