*7.2.1 Preparation*

ATA guidelines suggest achieving euthyroidism with anti-thyroid drugs and beta blockers in patients with total T4 > 20 μg/dl, and free T4 > 5 ng/dl prior to RAI therapy. Iodine intake has to be restricted atleast 1 week prior to I-131 therapy. Antithyroid medications are typically stopped 2–3 days prior to administering I-131. This is associated with potential risk of worsening thyrotoxicosis and precipitating thyroid storm after radioiodine therapy. Alternatively, 20% higher dose can be administered while patient is on anti-thyroid medication, minimizing the risk of thyroid storm. Either of these approaches have not been well studied in pediatric age groups.

ATDs are restarted only 1 week after RAI therapy to optimize the likelihood of successful ablation, although this is seldom required in children as thyroid hormone levels begin to decrease within one week after RAI treatment [18, 22, 31, 36].
