Looking at the worries of radiation

Talk about it

X-rays, CT scans and other types of imaging exams are often surrounded by controversy.

While some people don’t think twice about them, others fear that radiation exposure as a result of the exams will cause cancer. Area medical professionals urge patients to take a closer look at the facts about radiation — something many people don’t understand.

Comparing doses

“Radiation is kind of this mysterious invisible thing that science fiction movies have used a lot,” said Dr. Cynthia McCollough, the professor of Medical Physics and Biomedical Engineering at Mayo’s CT Clinical Innovation Center in Rochester.

“(People) don’t recognize that it’s just like anything. If I take a whole bottle of Tylenol — bad. If I take two Tylenol — not a problem,” McCollough explained.

What many patients don’t realize, McCollough said, is that the dose of radiation exposure from medical imaging is often far less than what a person is exposed to in everyday life.

Measured in a unit called millisieverts, radiation comes from some of the least expected places.

“Every time you eat a banana you’re eating radiation,” McCollough said. “But it’s tiny doses.”

According to Mayo Clinic, the dose of radiation a person can expect from an average dental X-ray is about .005 mSv. By comparison, a six-hour flight on an airplane exposes people to about .03 mSv of radiation.

“We get radiation from cosmic sources,” McCollough added. “The average background just from living on planet Earth is about 3 millisieverts a year.”

Medical imaging exams expose patients to varying doses of radiation, with chest X-rays as low as .1 mSv, mammograms .7 mSv and CT scans coming in closer to 7 or 10 mSv.

“Radiation therapy where you’re trying to damage so many cells that you can’t recover, they give tens of thousands of these millisieverts,” McCollough explained. “That’s the difference we’re talking.”

While McCollough said she isn’t trying to say there are absolutely no risks associated with radiation from medical imaging exams, she and other medical professionals are trying to help people understand that if the exams weren’t more positive than negative, they wouldn’t be offered.

“I try to get people to focus on the benefits,” she noted. “Radiation is not this really scary thing.”

Mayo Clinic points out in its brochure about radiation exposure: “For most imaging exams, the health benefits that may be gained from any medically necessary exam are very high compared to the small potential risk.”

Additionally, advancements in medical technology are allowing doses of prescribed radiation to decrease.

“That’s my job as a physicist to keep things as low as reasonable so it’s as safe as reasonable,” McCollough noted.

Still, she stressed, there’s no reason for people to expose themselves to more radiation than is necessary.

“Don’t use more than you need to.”

Extra precautions unneeded

With Breast Cancer Awareness Month coming to a close, women across the country have been encouraged to schedule a mammogram to help detect breast cancer as early as possible.

However, some women are less concerned about the potential of breast cancer and more concerned about radiation exposure from the actual screening.

While the use of a lead apron can give some patients peace of mind when heading into an appointment for a mammogram, medical professionals say neither lap nor thyroid aprons are necessary.

According to the American Association of Physicists in Medicine, “mammography machines are designed to ensure patient safety, incorporating internal radiation shielding, which prevents stray radiation.”

Not only that, but a screening may actually be negatively affected by the use of an apron or shield.

“The biggest thing that we emphasize is that, especially with mammograms, asking for a thyroid shield really puts you at risk for a bad exam,” McCollough said. “If you had a very bulky lead apron around your neck there’s a pretty good chance a part would come into the image, wrecking the image and then you’d have to repeat the whole exam.”

“The efforts that you take in anything ought to be sort of commensurate to the risk.”

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