In Children, Consider CT Scans' Long-Term Risks

ACEP News 
June 2009

By Denise Napoli
Elsevier Global Medical News


BALTIMORE -- CT scans are responsible for 91% of total radiation exposure in pediatric trauma patients, even though only 32% of imaging done in these patients is computed tomography, study results showed.

"Each provider has to decide: What's the benefit of getting the pictures that we get?" said Dr. Marissa A. Brunetti, an intensivist at Johns Hopkins Hospital in Baltimore.

"Especially with CT, ... if a patient is critical and the imaging study means the difference between life and death, then by all means get it. But there are times when imaging studies are done out of convenience or in place of other imaging modalities [like ultrasound] that could get pictures that are similar without radiation exposure," she said.

In a presentation at the annual meeting of the Pediatric Academic Societies, Dr. Brunetti reported on 729 patients aged 14 years and younger who were seen in the emergency department at her hospital over a 1-year time period. Transfer patients were excluded from the analysis, as were any follow-up imaging studies. In total, 1,457 CT studies and 4,603 radiographic studies were conducted on these patients during this period.

The average radiation dose for each patient was calculated to be 12.8 milli-sieverts (mSv), with a high dose of 73.5 mSv. "The average dose from the environment is about 3 mSv per year, so that's more than four times the annual dose," said Dr. Brunetti.

When the patients were stratified by type of injury, the 178 children whose trauma resulted from a motor vehicle accident registered the greatest level of radiation exposure, with an average of 18.6 mSv. Pedestrians struck by cars had the second highest level of radiation exposure, 15.6 mSv.

Part of the reason that possibly unnecessary imaging studies are done, she said, is that "pediatricians and providers don't know the doses that these images impart."

Education about which studies deliver the highest doses, and emphasis on keeping these studies to a minimum where possible, could lower patients' total radiation exposure.

Another problem lies with transfer patients, she noted. Although the study did not look at transfers to the hospital, an audience member pointed out that "there is this idea that my CT scanner is going to be better than the CT that is done in the community hospital," and so patients wind up having imaging studies repeated.

"For all patients, especially in the very young with long time horizons, the benefit of additional radiation exposure for diagnostic purposes should be weighed against the long-term risks of additional exposure," concluded Dr. Brunetti.

Dr. Brunetti said that she had no disclosures or conflicts of interest to report with regard to this study.

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