I-131 THERAPY FOR THYROID CANCER

INDICATIONS:

  1. Treatment of residual functioning thyroid cancer.
  2. Ablation of residual normal thyroid tissue post subtotal thyroidectomy in certain groups of patients.

PATIENT PREPARATION:

  1. The patient must not have taken thyroxine (T-4) for at least 4 weeks and triiodothyronine (T-3) for at least 1-2 weeks.
  2. The patient's iodine pool should be normal or low:

a) No iodinated radiographic contrast materials for approximately 3 weeks.

b) No food or vitamin sources with large amounts of iodine.

3.The patient is admitted to the hospital.

4. The patient should wear either a disposable gown or surgical scrub suit rather than personal night clothes.

5. The nuclear medicine physician explains the expected benefits and possible complications.

6. The nuclear medicine physician obtains oral informed consent from the patient.

7. Negative pregnancy test in women of child bearing age.

RADIOPHARMACEUTICAL:

1. I-131 is given orally as sodium iodide.

2 Dose:

> Ablation of residual normal thyroid tissue: 70-150 mCi.

> Treatment of functioning thyroid cancer: 100- 300 mCi.

PROCEDURE TIME:

  1. Initially: 20 minutes for obtaining informed consent and administering dose.
  2. Later: 20 minutes per day for monitoring patient's I-131 body burden until it is below 30 mCi.
  3. A post-therapy whole body scan is performed at time of discharge or 96 hr post therapy.

FOLLOW-UP:

  1. The patient usually returns to the care of the referring physician.
  2. A follow-up whole body I-131 study is usually performed approximately 6-12 months following cancer/ablation treatment.