Damian McNamara

November 04, 2013

ORLANDO, Florida — Children who undergo CT scanning at a dedicated children's hospital are exposed to significantly lower levels of radiation than children scanned at facilities that primarily treat adults, according to a new study.

"We were not surprised that nondedicated pediatric facilities are not adjusting their CT parameters for children. However, it was surprising just how much extra radiation children receive at these facilities," said Nicole Sharp, MD, from Children's Mercy Hospital in Kansas City, Missouri.

"Kids at our dedicated children's hospital received 86% less radiation in terms of size-specific dose estimate," she told Medscape Medical News.

Importantly, a lower radiation dose does not affect the accuracy of the diagnostic imaging, she noted.

Dr. Sharp presented the results, which garnered a lot of interest, here at the American Academy of Pediatrics 2013 National Conference and Exhibition.

 
Kids at our dedicated children's hospital received 86% less radiation in terms of size-specific dose estimate.
 

Her team assessed the charts of 163 children transferred to Children's Mercy Hospital after a CT scan for appendicitis at a nondedicated pediatric facility. They matched these for age and date of scan to the charts of 163 children scanned at their dedicated children's hospital for appendicitis. Mean patient age was 11 years.

They calculated radiation exposure using information from the CT dose card that accompanies each scan.

Although the amount of radiation was significantly lower at the children's hospital, the diagnostic outcome was not significantly different at the 2 facilities.

Table 1. CT Radiation Exposure and Appendicitis Diagnosis

Variable Children's Hospital Nondedicated Facility P Value
Dose-length product, mGy cm 253.78 619.53 <.001
CT positive for appendicitis 37% 39% .732
Pathology positive for appendicitis 95% 81% .026

 

A potential solution to this issue involves promoting routine adjustment of CT parameters at facilities that primarily image adults to appropriate pediatric levels, Dr. Sharp said. "We urge outside facilities to update their CT standards or to consider referral of patients to a dedicated children's hospital."

After the introduction of the CT dose-length index in February 2012, a more significant difference in radiation exposure emerged. Researchers assessed a subset of 65 charts in each group using 3 measures of exposure.

Table 2. Subgroup Analysis of Radiation Dose

Mean Dose Children's Hospital Nondedicated Facility P Value
Dose-length product, mGy cm 143.54 586.25 <.001
CT dose-length index, mGy 4.89 16.98 <.001
Size-specific dose estimate, mGy 3.81 26.71 <.001

 

This study adds to "growing literature emphasizing the need for all hospitals and physicians to be vigilant about decreasing the exposure of children to unnecessary, excess ionizing radiation," said Christopher Weldon, MD, from Boston Children's Hospital.

"In light of the differential secondary effects of ionizing radiation in children vs adults, the way the CT scanner is employed is as important as what it is being used to diagnose," he told Medscape Medical News.

After the presentation, an audience member asked about the high percent of patients who underwent CT scanning at Children's Memorial Hospital.

"We didn't look at the percentage of children who had appendicitis and got a CT scan," Dr. Sharp answered. But, she said, "we acknowledge the overuse of CT scans at our facility during this time."

The audience member also wondered if all children who underwent CT scanning had an ultrasound examination first.

"I can tell you that the number of children who received ultrasound before the CT scan during this time was low. It was low at outside facilities as well," Dr. Sharp said. "Our emergency department physicians work up these patients before we see them. We need to emphasize a physical exam and ultrasound prior to doing CT scans."

"Thank you for adding fact to the emotion of this argument," said Steven Stylianos, MD, from Columbia University College of Physicians and Surgeons and New York-Presbyterian/Morgan Stanley Children's Hospital in New York City. He asked Dr. Sharp if she could recommend a solution other than suggesting behavioral change, which has had disappointing results in the past.

"One of the best ways we have is to emphasize to our primary care colleagues the importance of using physical exam and ultrasound prior to ordering a CT scan — to essentially protocolize it, if possible," Dr. Sharp explained.

Dr. Sharp and Dr. Weldon have disclosed no relevant financial relationships.

American Academy of Pediatrics (AAP) 2013 National Conference and Exhibition. Presented October 26, 2013.

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