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

Inclusion Criteria: * 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 informed consent document, and the willingness to sign it * Subject is not pregnant Exclusion Criteria: * 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