Two-thirds get medical tests with radiation dose

As many as two-thirds of adults underwent a medical test in the last few years that exposed them to radiation and in some cases, a potentially higher risk of cancer, a study in five areas of the U.S. suggests. It is the latest big attempt to measure how much radiation Americans are getting from sometimes unnecessary medical imaging. Though the annual average radiation exposure from X-rays, CT scans, and other tests was low, researchers found about 20% were exposed to moderate radiation doses and 2% were exposed to high levels.