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Radioiodine Whole Body Scan (I-131)

Overview

A radioiodine whole-body scan is performed for patients with thyroid cancer to assess the state post-surgery. It helps doctors detect any remaining thyroid tissue or cancer cells and guides future treatment planning.

Your doctor may recommend a radioiodine scan to:

  • Evaluate thyroid cancer after surgery or treatment
  • Detect residual thyroid tissue or spread of thyroid cancer
  • Plan dosage of therapeutic radioiodine

  • 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: You will then have to return for the scan, usually 24–48 hours after taking the iodine, depending on what information your doctor needs.
  • Scan: You will be asked to lie down on a table, and a special gamma camera will capture images of your thyroid gland. The scan is painless and takes around 30 to 60 minutes.

  • Radioiodine administration: a few minutes
  • Waiting period: 1–2 days (depending on what the doctor needs to evaluate)
  • Scan itself: 30–60 minutes

  • Dietary Restrictions: You will be asked to follow a low-iodine diet 1–2 weeks before the scan.
  • Medications: Some medications need to be stopped temporarily before the scan. Please contact the Nuclear Medicine department or your doctor for details.
  • Pregnancy and breastfeeding: Inform your doctor if you suspect you may be pregnant or if you are pregnant or breastfeeding. This scan is generally not recommended during pregnancy or breastfeeding.

  • The scan is generally safe with minimal risks.
  • The scan poses radiation exposure, comparable to other nuclear medicine scans.

  • You can usually return to your normal activities immediately after the scan.
  • The radioactive iodine will pass naturally through your body, usually within a few days.
  • Drink plenty of water after the scan to help flush out the radioactive iodine from your body.

Disclaimer:

The information in this Health Library is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional with any questions about a medical condition or before starting any treatment. Use of this site and its content does not establish a doctor–patient relationship. In case of a medical emergency, call your local emergency number or visit the nearest emergency facility immediately.