The use of CTs, MRIs and other advanced medical imaging tests has soared over the past 15 years, according to new research that raises questions about whether the benefits of all these scans outweigh the potential risks from radiation exposure and costs to the healthcare system.

An examination of data from patients enrolled in six large health maintenance organizations found that doctors ordered CT scans at a rate of 149 tests per 1,000 patients in 2010, nearly triple the rate of 52 scans per 1,000 patients in 1996. MRI use nearly quadrupled during the period, jumping from 17 to 65 tests per 1,000 patients, according to results published in Wednesday's edition of the Journal of the American Medical Assn.

These and other tests have meant that more patients have absorbed more ionizing radiation as part of their medical care. The proportion of patients in the study who had any amount of radiation exposure — driven by the use of CTs — rose from 28.5% in 1996 to 36.2% in 2010; among them, their average exposure jumped from 4.8 millisieverts to 7.8 millisieverts. At the top end of the spectrum, the proportion of patients in the study who got radiation at high or very high levels rose from 1.8% to 3.9%.

"We've become victims of our own technology," said Dr. George Bisset, chief of pediatric radiology at Texas Children's Hospital in Houston and president of the Radiological Society of North America.

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