TABLE 1

Summary of Appropriate Patient Preparation for 131I DWBS

Appropriate patient preparation
Withdrawal of T4 for 4–6 wk or of T3 for 2 wk.
A strict low-iodine diet (≤50 μg iodine per day) followed for 7–14 d before 131I DWBS and continuing throughout period of imaging.
Avoidance of iodine-containing medications (e.g., iodinated contrast medium, amiodarone, betadine), iodine-rich foods (e.g., kelp), and possible additives of iodine in vitamin and electrolyte supplements.
TSH ≥ 30 mIU/L.
A mild laxative sometimes administered on the evening before 131I DWBS to simplify image interpretation.
Information relating to patient’s compliance with low-iodine diet, TSH level, history of thyroid hormone withdrawal, measurement of Tg, history of prior administration of contrast medium or iodine-containing drugs (e.g., amiodarone), menstrual history/pregnancy test, nursing/lactation history, etc.
Measurement of urinary iodine in doubtful cases to rule out iodine contamination; repeated WBS 4–6 wk after iodine-depletion regimen such as diuretic program.
Rule out women with pregnancy and breast feeding.

  • T3 = triiodothyronine.