Friday, May 15, 2009

I-131 Basics: Radioactive Iodine in the Treatment of Thyroid Cancer

As you probably already know, as a follower of my blog and facebook pages, my baby girl (22 years old, but forever my baby anyway) is a metastatic thyroid cancer patient. Most people simply assume that since thyroid cancer is generally referred to as a type of cancer with high cure rates and survival statistics, it is not a cancer we need to concern ourselves with much.

Well I hate to be the one to have to wake you up from the "fantasy" of a cancer many insensitive medical professionals and ill informed people call the "best cancer you can have".

~~Cancer~~ a devastating word to hear, and a phenomenally frightening diagnosis to deal with emotionally, physically and financially no matter the type, stage or age at onset.

In the case of thyroid cancer, the fastest increasing newly diagnosed cancer in America today, the many long term unknowns for the growing number of young survivors is not as reassuring as orignally thought of. A growing number of young people are developing persistent and/or recurrent cancer in the thyroid bed, many are developing metastatic disease like my daughter. Some may be genetically predisposed to the condition, many others will never know why they hit "the thyroid cancer lottery" at all. Yet another small percentage of survivors will develop another type of cancer somewhere down the line as result of the treatmetn they receive to treat the original thyroid cancer at an early age.

In this section/article I will share with you what nobody told me and you should know about I-131 RAI Treatment for thyroid disorders is the isotope used to destroy both normal and cancerous thyroid tissue.


Small doses of I-131 (5 t0 30 millicures, mCi) are given to destroy or "ablate" overactive thyroid tissue. This usually turns an overactive thyroid gland, with time, into and underactive thyroid gland. Doses of I-131 in the middle range (25 to 75 mCi) may be used to shrink large thyroid glands or goiters that are functioning normally but are causing breathing problems because their large size my compress the trachea (windpipe).

Patients must go directly home after I-131 RAI treatment, although they are asked to follow certain precautions. Temporary worsening of hyperthyroid symptons may occur within the first two weeks of I-131 treatment for hyperthyroidism, which can be easily treated with medicines called beta blockers. This medicine will be prescribed by your doctor. It is also common for patients to experience some temporary discomfort in the thyroid gland or lower neck area within 1 to 14 days after I-131 treatment for hyperthyroidism.

The discomfort may mimic the feeling of a sore throat. Aspirin, Ibuprofen (Advil) or Acetaminophen (Tylenol) may be used to treat discomfort. These side effects may last up to two weeks. The RAI treatment may take up to one to six months to have it's full effect. A small percentage of patients may require a second course of treatment.


Ablative doses of I-131 RAI (50 to 120 mCi) are usually given to destroy any remaining normal thyroid tissue that is commonly left following thyroidectomy. Because of the vital structures in the area of the thyroid gland, the surgeon may leave a small amount of thyroid tissue or gland behind, specially to preserve the tiny parathyroid glands that are embedded along the posterior (back side) of the thyroid gland. The remaining thyroid tissue will usually out-compete any thyroid cancer for the I-131 uptake ! Therefore, any residual thyroid tissue must be removed before persistent thyroid cancer or spread of thyroid cancer (metastatic disease) may be evaluated.

A post ablation thyroid scan is performed 10-14 days after thyroid ablation therapy which may show a large thyroid tumor, but mainly serves as a baseline study for future comparison. Larger doses of I-131 (80 to 200 mCi) are used to destroy residual thyroic cancer or any spread of the tumor to other sites or internal organs (metastatic disease). I-131 has been referred to as the "magic bullet" for treating most common types of thyroid cancer but as with any cancer early detection and early treatment are key in the race to cure theses types of cancers. In the case of my daughter Stevie JoEllie, but rarely in most cases, even higher doses of I-131 are given and most hospitals will generally keep you isolated in a special room anywhere from 24 hours to a few days to avoid exposing other people to radiation.

Please remember unless you receive unusually high doses of I-131 you will be allowed to return home the same day you receive your treatment, although precautions should be taken if you have small children or pets in your home, it is perfectly safe for most patients receiving small to medium I-131 doses to rest at home for a few days before returning to their regular activities. Keep in mind that since salivary glands weakly concentrate iodine, no matter what dose of I-131 you receive, there may be discomfort and swelling of the salivary glands. This can be prevented or greatly reduced by sucking on lemon drops or sour candies for up to 2 weeks after your I-131 treatment.


This list outlines radiation exposure precautions to observe to minimize risks for your family, friends and co-workers after treatment. Please remember to consult your doctor and follow his instructions for YOU -- the precaution durations vary according to the dose of I-131 you receive.


  • Drink 12 -8oz glasses of fluids daily 2 to 7 days
  • Do not prepare food for others 2 to 7 days
  • Do not share utensils with others 2 to 7 days
  • Flush toilet 2 to 3 times after each use 2 to 7 days
  • Keep a distance of 6 feet from children 2 to 7 days
  • Keep a distance of 6 feer from pets 2 to 7 days
  • Sleep in a separate bed or room 2 to 11 days
  • Avoid close physical contact such as hugs 2 to 11 days
  • Avoid kissing and/or sexual activity 2 to 11 days
  • Limit time in public places 2 to 7 days
  • Delay return to work or school 2 to 7 days
  • Do not travel by airplane of public transportation a minimum of 7 days but up to 14 days
  • Do not travel on prolonged car rides or bus rides a minimum of 7 days but up to 14 days


About the Author: Wilma Ariza is the founder of Stevie JoEllie's Cancer Care Fund a thyroid cancer awareness, access to care and free supportive services for thyroid cancer patients and survivors nonprofit 

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