Computed tomography (CT) scans and nuclear imaging have revolutionized the diagnosis and treatment of many conditions and have almost eliminated the need for once-common exploratory surgery. But will we pay a price—more cases of cancer—for these advances? The October 2010 issue of Harvard Women’s Health Watch takes up this important question.

Mammograms, chest and dental x-rays, bone density tests, and other types of x-rays deliver only small amounts of radiation to the body, and so add little to future risk of cancer. In contrast, a CT scan delivers 70 times as much radiation as a chest x-ray. And since 1980, there has been a 20-fold increase in the use of CT scanning and nuclear imaging. Many experts are concerned about this extra burden of radiation.

Because it takes years, if not decades, for medical radiation to cause cancer, these tests pose fewer problems for older people. Exposure to medical radiation earlier in life is more problematic. Until we know more about possible connections between medical radiation and future cancer risk, it's best to keep your exposure as low as possible, notes Harvard Women’s Health Watch. Here’s how:

Discuss imaging with your clinician. If your clinician has ordered a CT scan, ask what difference the result will make in how your condition is managed; for example, will it save you an invasive procedure?

Keep track of your exposure. Keep a record of your exposure to x-rays, CT scans, and other medical radiation. Your list won’t be completely accurate, but it will give you and your clinician a ballpark estimate of your radiation exposure.

Consider a lower-dose test. If your clinician recommends a CT or nuclear medicine scan, ask if another technique would work just as well.

Don’t seek out scans. Don’t ask for a CT scan just because you want to feel like you’ve had a “thorough checkup.”

Read the full-length article: "A doctor talks about: Radiation risk from medical imaging"