Mehmet Oz, MD, a physician and television personality, recently discussed a possible connection between thyroid cancer and the radiation in mammograms.  Since then, we have heard from a few patients who are concerned about this potential link – so here are some facts about mammograms and radiation exposure.

First, it’s important for people to keep in mind that we are exposed to radiation every day, from materials in the earth, from radon in the air, from outer space, and even from inside our own bodies – as a result of the food and water we consume.

The amount of radiation your body absorbs can be measured in millisieverts (mSv). A mammogram exposes you to approximately 0.2 mSv.  The dose to your thyroid gland is less than 0.002 mSv.

To put this in context, the naturally occurring background radiation in our environment exposes you to approximately 3 mSv per year.  If you live at higher elevations – say, 6000 feet above sea level – you absorb an additional 0.26 mSv per year.  Spend just 24 minutes flying in an airplane and you absorb 0.002 mSv.  And if you live in a stone, brick or concrete building you will absorb another 0.07 mSv per year, because there may be slightly more naturally occurring radioactivity in these building materials.

So there is no escaping a certain amount of radiation.  And the amount of radiation your thyroid gland absorbs from a mammogram is well within the parameters of the amount of radiation you absorb just living on this planet.

If you are wondering whether you should ask about wearing a thyroid shield in your next mammogram, you should know that there are drawbacks: sometimes the shield can obscure a useful view of breast tissue, and then you might have to have a repeat mammogram, exposing you to double the dose of radiation.

In fact, the American College of Radiologists and the Society of Breast Imaging do not recommend use of a thyroid shield – here’s a link to their recent press release on the topic:

I hope this reassures you that the amount of radiation absorbed by your thyroid gland in a mammogram is safe. If you still have concerns, we encourage you to talk to your health care team.  We want you to feel comfortable with any procedure that you have here at the UVM Medical Center.

And remember, having an annual screening mammogram has proven health benefits for women over 40. Don’t let fears of radiation prevent you from getting the life-saving benefits of a mammogram.
Dan Beideck, MS, DABMP, is a medical imaging physicist at the University of Vermont Medical Center, and an Assistant Professor at the Larner College of Medicine at UVM. 

Sally Herschorn, MD, is Director of the UVM Medical Center’s Breast Imaging Department and Associate Professor of Radiology at the Larner College of Medicine at UVM. 

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