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Radioactive Iodine 131 Therapy for Overactive Thyroid Gland

Radioactive Iodine 131 therapy for overactive thyroid gland is a treatment in which radioactive iodine in an oral form, is given to patients with overactive thyroid glands.

It is used to decrease the amount of hormones produced by your thyroid gland.

Before Your Procedure

  • Tell your physician if you are pregnant or nursing.
  • If you are a female of childbearing age, you will have a lab test performed to verify that you are not pregnant.
  • You must be off most of your thyroid medications prior to your therapy.
  • Your physician will instruct you as to which medications you may continue to take.
  • Do not eat or drink anything 2 hours before therapy.

During Your Procedure

  • A radiologist will explain the therapy, its benefits and risks involved.
  • You will be given a capsule containing a therapeutic dose of radioactive iodine.
  • The thyroid absorbs and concentrates the radioactive iodine.
  • The treatment destroys thyroid tissue while sparing the rest of the body.
  • Within days after the treatment, most of the radioactive iodine that is not taken up by your thyroid gland is eliminated from your body through the urine.
  • Do not eat for at least 2 hours after taking the capsule.

After Your Procedure

  • Thyroid hormone levels may take 8-12 weeks to return to normal.
  • Your physician will receive a report of the therapy.

Providing safe, quality patient care is our highest priority. To help ensure quality and safety, we ask that you do not bring young children with you to your appointments, as children are not allowed to accompany you during Imaging procedures. Staff is unable to monitor your child in your absence.

If you have any questions or concerns, please contact your provider.

Back to Imaging Patient Instructions

Dear Friends and Neighbors,

CentraCare care givers have been working around the clock for more than 20 months to care for you, your families and friends during COVID. We are committed to caring for every Minnesotan who needs us, and nothing will prevent us from doing so – even during these never-seen-before times.

The challenge of providing this level of care is that our hospital beds are often full. ERs in all of our hospitals are packed. And our clinical teams are exhausted. Early in the pandemic, our community stepped up in amazing ways to help us. We ask that you again join us in fighting this pandemic together.

How can you help?

  • Please get your COVID vaccines and booster shots. They are proven safe and effective in reducing COVID illness, keeping people out of the hospital, and preventing death.
  • If your situation is not an emergency, please use other care options, including:
  • If this is a medical emergency, call 9-1-1, or visit the ER.

Together, we can do this. Thank you for your support.

Ken Holmen, MD
President and CEO