Robert Ferry Jr., MD, is a U.S. board-certified Pediatric Endocrinologist. After taking his baccalaureate degree from Yale College, receiving his doctoral degree and residency training in pediatrics at University of Texas Health Science Center at San Antonio (UTHSCSA), he completed fellowship training in pediatric endocrinology at The Children's Hospital of Philadelphia.
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
131-iodine (131I or I-131) is the radioactive isotope used to kill both normal and cancerous thyroid cells
This is not to be confused with I-123, a harmless isotope used by radiologists in imaging and to determine thyroid activity
Radioactive iodine is safe to use in people who have allergic reactions with other iodine-containing compounds, including seafood and intravenous (IV) contrast media
The amount of elemental iodine in radioactive iodine is smaller than that in our daily diet
The three major uses for I-131 therapy
nontoxic multinodular goiter
I-131 can be given to patients who have overactive thyroid tissue or enlarged thyroid glands to destroy normal thyroid tissue
Typically, the I-131 takes several months to have its full effect for eliminating the thyroid tissue
2) Thyroid cancer
Larger doses of I-131 are used to kill thyroid cancer cells
3) Nontoxic multinodular goiter
Used in Europe to shrink multinodular goiters by about 40%, but not typically used in the United States
Side effects are rare and easily treatable and include nausea, and pain or swelling of the thyroid tissue and salivary glands
Safety of radioactive iodine I-131
I-131 should never be used in women who are pregnant;
Pregnancy should be deferred by 6 months after I-131 therapy;
Long-term fertility is not affected in either men or women;
For lower doses of I-131 used for hyperthyroidism, the Nuclear Regulation Commission does not require isolation; still, general exposure to children and pregnant women should be avoided for 3 days after the treatment;
For larger doses of I-131 used in thyroid cancer patients, exposure to children and pregnant women should be avoided for 3 to 7 days after the treatment; and
Exposure of others to the body fluids (saliva, urine, nasal secretions, etc.) of a patient who has been recently treated with I-131 should be limited or avoided completely.