Radio-iodine whole body scan (I-131) Home A-Z Health Information Health Library A-Z Radio-iodine Whole Body Scan (I-131) Overview A Radioiodine whole-body scan is performed for patients with thyroid cancer to assess the state post-surgery.The procedure involves taking a small amount of radioactive iodine, which is absorbed by the thyroid gland. A gamma camera then takes images to assess how your thyroid absorbs iodine and how it functions.Doctors recommend a radioiodine scan to:Evaluate thyroid cancer after surgery or treatmentPlan dosage of therapeutic radioiodine How Should I Prepare for the Scan? Dietary Restrictions: You will be asked to follow a low-iodine diet 1-2 weeks before the scan.Medications: Few medications need to be stopped before the scan. Please contact the Nuclear Medicine department or your doctor.Pregnancy and breastfeeding: Inform your doctor if you suspect you may be or are pregnant or breastfeeding. This scan is generally not recommended during pregnancy or breastfeeding. What Happens during the Procedure? Radioiodine administration: You will be given a small dose of radioactive iodine, either in the form of a pill or a liquid. This iodine will be absorbed by your thyroid gland over several hours.Waiting period: After taking the iodine, you will then have to return the next or day after for the scan depending on what information you doctor needs.Scan: You will be asked to lie down on a table, and a special camera will capture images of your thyroid gland. The scan is painless and takes around 30 to 60 minutes. What Should I Expect After the Procedure? You can usually return to your normal activities right after the scan.The radioactive iodine will pass naturally through your body, usually within a few days.Drink plenty of water to help flush out the iodine.