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Radioactive Iodine Treatment

  • Amy Scholten, MPH
Publication Type:


Radioactive Iodine Treatment

(Radioiodine Treatment)


This procedure uses radioactive iodine to destroy cells in the thyroid.

The Thyroid Gland.

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Reasons for Procedure

Radioactive iodine may be given to treat:

Possible Complications

Problems are rare, but all procedures have some risk. The doctor will go over some problems that could happen, such as:

  • Painful cheeks or neck pain
  • Metallic taste in the mouth, or a dry mouth
  • Sore throat or tightness in the throat
  • Nausea or vomiting
  • Tiredness
  • Flushing
  • High or low thyroid hormone levels

The procedure may be harmful to a fetus. It is not advised for pregnant women. Nursing mothers should stop breastfeeding for at least a week after the procedure.

What to Expect

Problems to Look Out For

Call your doctor if you are not getting better or you have:

  • Signs of infection, such as fever or chills
  • Nausea or vomiting
  • Excessive tiredness
  • Swelling in the neck or pain that gets worse
  • Problems passing urine (pee)
  • Tightness in throat or trouble breathing
  • Numbness in the face
  • Fast heartbeats

If you think you have an emergency, call for medical help right away.





  • Fact sheet: guidelines for patients receiving radioiodine I-131 treatment. Society of Nuclear Medicine & Molecular Imaging website. Available at: https://www.snmmi.org/AboutSNMMI/Content.aspx?ItemNumber=5609.
  • Huang, J., Harris, E.J., et al. Treatment of aggressive thyroid cancer. Surgical Pathology Clinics, 2019; 12 (4): 943-950.
  • Radioactive iodine. American Thyroid Association website. Available at: https://www.thyroid.org/radioactive-iodine.
  • Radioactive iodine (radioiodine) therapy for thyroid cancer. American Cancer Society website. Available at: https://www.cancer.org/cancer/thyroid-cancer/treating/radioactive-iodine.html.
  • Radioactive iodine for hyperthyroidism. Endocrine Society Hormone Health Network website. Available at: https://www.endocrine.org/patient-engagement.
  • Radioiodine (I-131) therapy. Radiological Society of North America Radiology Info website. Available at: https://www.radiologyinfo.org/en/info/radioiodine.
  • Thyroid cancer. EBSCO Nursing Reference Center Plus website. Available at: https://www.ebsco.com/health-care/products/nursing-reference-center-plus.


  • James Cornell, MD
Last Updated:

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.