January 4, 2011

Concern Over Medical Radiation Exposure In Kids

Children and teens frequently undergo diagnostic tests that expose them to radiation, raising their risks of cancer later in life, according to a new study by researchers at University of Michigan and Emory University.

"In just a three-year span, 42.5 percent of kids got some form of ionizing radiation from a diagnostic medical procedure," Dr. Adam Dorfman, clinical assistant professor of pediatrics and communicable diseases and radiology at the U-M Medical School, told Reuters Health.

While the rapid growth of the use of medical diagnostic imaging, such as CT scans, has led to widespread concern about radiation exposure in adults, the current study shows that kids are also frequently receiving these types of imaging procedures during their routine care.

The research highlights the importance of initiatives to ensure these tests are necessary, and that they use the lowest possible doses of radiation.

"Our findings indicate that more awareness about the frequent use of these tests may be needed among care providers, hospitals and parents," Dr. Dorfman wrote in a statement.

"Imaging tests are a critical component of good medical care, but the high number of tests raises questions about whether we are being judicious in our use of the technology."

Despite widespread discussions about the health hazards of environmental exposures in children, radiation exposure from the frequent use of imaging procedures has received less attention, possibly due to limited contemporary data in younger patients.

The researchers identified 355,088 children under the age of 18 in five major U.S. health care markets, and tracked how often these imaging procedures were used.

They found that over 400,000 imaging procedures were performed in just 3 years, ranging from routine x-rays that use very low doses of radiation to more advanced tests, like CT scans, that require greater doses.

The study found that 42.5% of the children received at least one of these procedures, with many undergoing multiple tests. 

Based on the data, the average child in the study would be expected to receive approximately 7 imaging procedures utilizing radiation by age 18.

The study focused on the numbers and types of procedures performed, but did not calculate specific doses of radiation that were received by each child. 

"What we've tried to do is raise awareness of the issue and start a national dialogue by identifying the overall scope of the problem," Dorfman said.

"One limitation of this type of analysis is that the clinical appropriateness of the tests could not be determined."

"The next step is to better understand when these tests really add value to the care of a child and when they do not."

Among the tests that the researchers studied, CT scans were the most important from the standpoint of radiation exposure.  Indeed, 8% of the children in the study received a CT scan during the 3-year research period, with 3.5% of the children receiving more than one.

Understanding patterns of utilization of these tests in children is critical because children and infants are more susceptible than adults to the risks of radiation exposure, such as future cancers.

"Developing tissues in children are more sensitive to radiation and their longer expected life spans also allows additional time for the emergence of detrimental effects," wrote Dr. Reza Fazel, a cardiologist at the Emory School of Medicine and a co-author of the study.

However, Fazel cautioned that the risk for any individual child undergoing a single test is typically low.

"Of course, there is immense life-saving value in medical imaging, so our study doesn't suggest at all that these tests shouldn't be used in children," said co-author Dr. Kimberly Applegate, vice chair for Quality and Safety in the Department of Radiology at Emory University.

"We have to be smarter about how we use tests. For example, children don't always need the same radiation dose during a CT scan to get the same quality of image and information."

The researchers note that each imaging procedure should be guided by the principle of ALARA, or As Low As Reasonably Achievable, which advocates for minimizing radiation doses while still obtaining sufficient clinical information.

Dr. Andrew Einstein, another study co-author and a cardiologist at Columbia University, said the study should not deter parents from imaging procedures that may provide a clear benefit for their kids.

"It should encourage discussions about the value of each imaging test that is ordered, recognizing that radiation exposure, even in small amounts, may not be risk free."

The study was published online today in the Archives of Pediatrics and Adolescent Medicine.


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