Preparation

All patients must discontinue medications that could affect the ability of thyroid tissue to accumulate iodine.
Follow a low iodine diet for 2-3 weeks before the day of treatment.
The nuclear medicine physician will give you a list of precautions to take following your treatment with I-131.
The patient must be NPO 2 hours before and after the oral administration of I-131.
The patient simply swallows a prepared dose of I-131.

Precautions:

Radioiodine therapy is not used in a patient who is pregnant. Also, it is recommended that pregnancy be delayed until at least six to 12 months after I-131 treatment.
The treatment should not be used in women who are breastfeeding unless they are willing to cease breastfeeding their newborn.