2. Subspecialties
  3. Nuclear Medicine and Molecular Imaging
  4. I-131 NaI Radioligand Therapy

I-131 NaI Radioligand Therapy

Iodine-131 (I-131) Sodium Iodide Therapy

Targeted radionuclide therapy for hyperthyroidism and thyroid cancer

Overview

Iodine-131 sodium iodide is an oral radioactive iodine therapy that takes advantage of the thyroid gland’s natural ability—and, in many differentiated thyroid cancers, retained ability—to concentrate iodine. The emitted beta radiation treats iodine-avid thyroid tissue, while gamma emissions permit imaging when clinically indicated.

FDA Approval and Who May Benefit

Therapeutic sodium iodide I-131 has long-standing FDA approval for treatment of hyperthyroidism and thyroid carcinomas that take up iodine. The administered activity is individualized according to the indication, disease extent, prior treatment, thyroid or tumor iodine avidity, patient-specific risk factors, and applicable guidelines.

Why This Therapy Is Useful

I-131 can selectively treat functioning thyroid tissue without surgery. In hyperthyroidism, it can provide definitive treatment of overactive thyroid tissue. In differentiated thyroid cancer, it may be used for selected patients for remnant ablation, adjuvant treatment, or treatment of iodine-avid recurrent or metastatic disease.

What to Expect / Typical Protocol

  • Before treatment: Nuclear Medicine reviews the diagnosis, pathology and staging when applicable, thyroid function tests, pregnancy/breastfeeding status, medications and supplements that may interfere with iodine uptake, recent iodinated contrast exposure, and relevant imaging.
  • Preparation: Depending on the indication, patients may require a low-iodine diet, adjustment of antithyroid medication, and—when treating thyroid cancer—TSH stimulation through thyroid hormone withdrawal or recombinant human TSH.
  • Treatment: I-131 is generally administered orally as a capsule or liquid. Activity is individualized; higher activities may require additional radiation-safety planning or inpatient treatment depending on the administered activity and patient circumstances.
  • After treatment: Patients receive detailed written radiation-safety precautions regarding distance from others, sleeping arrangements, hygiene, travel, and contact with children or pregnant individuals.
  • Imaging and follow-up: Post-therapy whole-body imaging is commonly performed after thyroid-cancer treatment to evaluate iodine-avid tissue. Long-term follow-up is coordinated with endocrinology, oncology, surgery, and other treating clinicians.

Refer a Patient for I-131 NaI Therapy

The Division of Nuclear Medicine at UTHealth Houston offers comprehensive evaluation and treatment with radio-active iodine for eligible patients with hyperthyroidism and thyroid cancer.

Our multidisciplinary team provides:

  • Comprehensive eligibility assessment
  • Imaging review and treatment planning
  • Coordination of laboratory testing and scheduling
  • Administration of radio-iodine therapy
  • Post-treatment imaging and follow-up in collaboration with the referring physician

How to Refer:

Community physicians and other healthcare providers may refer patients by:

  • Faxing the referral and relevant clinical records to: 713-704-1360
  • Emailing one of our Nuclear Medicine faculty members by selecting a physician profile above.

Please include, when available:

  • Recent clinic note
  • Pathology reports
  • Relevant imaging reports (including I-123/I-131 scan, if performed)
  • Recent laboratory results (CBC, CMP, renal and thyroid function tests)
  • Current medication list and prior cancer treatments

Our team will promptly review the referral, contact the patient if appropriate, and coordinate consultation and treatment while maintaining close communication with the referring physician throughout the patient’s care.