Evaluation of 18F-TFB PET/CT Scan in Patients With Differentiated Thyroid Cancer

Who May Qualify: - Subject has biopsy-proven papillary or follicular thyroid cancer - Subject is clinically indicated for 123I-SPECT/CT total body iodine (TBI) scan - Subject agrees to undergo 18F-TFB PET/CT scan following TBI scan - Karnofsky performance status of \>= 50 (or Eastern Cooperative Oncology Group \[ECOG\]/World Health Organization \[WHO\] equivalent) - Subject is able to be scanned - able to lie still on SPECT/CT and PET/CT scanner table for up to 65 minutes (min) - Age 18 or older - Ability to understand a written willing to sign a consent form document, and the willingness to sign it - Subject is not pregnant Who Should NOT Join This Trial: - Contrast-enhanced CT within 4 last weeks - Amiodarone within last 4 months - Ingested iodine, kelp tablets, Lugols iodine, or potassium iodide (SSKI) within 2 weeks - Unable to lie flat, still or tolerate a PET scan - Applied betadine, iodoform, or quick tanning products to skin within last two weeks - If using medication withdrawal for stimulation, then exclude if thyroid stimulating hormone (TSH) level \< 25 - Taken anti-thyroid medication within 1 week - Subject is breastfeeding - Positive pregnancy test Always talk to your doctor about whether this trial is right for you.