Radioactive Iodine 131 Therapy for Overactive Thyroid Gland

What Is Iodine 131 Therapy for Hyperthyroidism (Overactive Thyroid Gland)?

Radioactive Iodine 131 therapy is a treatment for patients with an overactive thyroid gland to decrease the amount of hormone produced.

Before the Appointment

Providing safe, quality patient care is our highest priority. For the best experience please properly prepare for your appointment:

  • A pregnancy test is required for ages 10-60 years unless the patient has prior total hysterectomy.
  • Certain medications cannot be taken prior to appointment; your doctor will provide instructions to adjust your medication.
  • Inform your physician if you have had any CT contrast in the last 6 weeks as it can affect the therapy.
  • Do not eat or drink anything 2 hours prior to and 2 hours after the appointment.
  • Do not bring children with you to your appointment. For their safety children are not allowed to accompany you in the exam room. Staff are unable to monitor children.

During the Appointment

A Nuclear Medicine technologist will explain and provide the therapy.

  • A capsule containing a therapeutic dose of radioactive Iodine 131 is ordered specifically for you. The amount was either calculated by our radiologist based on prior imaging, or by your doctor.
  • A technologist provides education and guidelines for the therapy. Once completed and singed, the capsule is given to you.
  • After taking the capsule the thyroid absorbs and concentrates the radioactive iodine treating the overactive gland and spares the rest of the body.
  • Do not eat or drink 2 hours after receiving the Iodine 131 capsule.

After the Appointment

  • Follow guidelines given to you by the technologist.
  • Increase your fluid intake unless otherwise directed by your doctor.
  • Within days of the treatment, most of the radioactive Iodine 131 that is not taken up by the thyroid gland is eliminated from your body through urine.
  • The radioactive tracer used for this test is Iodine 131 in capsule form.
  • Thyroid hormone levels may take between 8-12 weeks to return to normal. Please follow up with your ordering physician to determine steps following treatment.
  • Follow-up care is a key part of your health. Be sure to make and go to all appointments and call your primary care provider if you have questions.

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

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