Staff Training Reduced Pediatric CT Dose, Maintained Image Quality

Undergoing a short, but intensive training helped radiologic staff to effectively reduce the radiation dose absorbed by pediatric patients undergoing head CT examinations, according to the results of an Italian study published in American Journal of Roentgenology.

Researchers led by Fabio Paolicchi, PhD, of the department of diagnostic and interventional radiology, University of Pisa, Italy, were able to reduce the radiation dose with an associated reduction in tube voltage and tube current-rotation time.

“For many years pediatric CT examinations have been performed with adapted adult protocols instead of natively pediatric ones,” the researchers wrote. “However, an arbitrary reduction of radiation dose may potentially result in substantial loss of image quality, highlighting the need for radiologists and technologists to optimize CT protocols in an effort to balance image quality and radiation dose.”

The researchers collected information on the absorbed radiation dose on patients undergoing head CT at three radiologic centers at their institution between January and June 2011. Data were from 215 outpatients aged one month to 14 years.

Subsequently, staff at these centers participated in an intensive training course that consisted of two consecutive, full-day training events where medical, biological and technical topics related to CT were discussed. Participants were then evaluated on their knowledge and CT protocols were revised based on feedback about patient characteristics, diagnostic query, radiation dose and image quality. Information on absorbed radiation dose was collected from January to June 2012.

For the analysis, patients were divided by age into three groups: 0 to four years, five to nine years and 10 to 14 years. Significant reductions in CT dose index and dose-length product were seen for all age groups when comparing rates before and after training (P<.001):

• 0 to four years: CTDI from 107 mGy to 27 mGY; DLP from 1,444 mGy per cm to 338 mGy per cm.

• Five to nine years: CTDI from 68 mGy to 41 mGy; DLP from 976 mGy per cm to 483 mGy per cm.

• 10 to 14 years: CTDI from 107 mGy to 51 mGy; DLP from 1,480 mGy per cm to 679 mGy per cm.

Additionally, staff training resulted in a significant reduction in tube current-rotation time product and tube voltage values. Tube-current rotation values were especially reduced in children aged 0 to four with an initial rate of 420 mAs compared with a rate of 125 mAs after training. For tube voltage, the most commonly used setting prior to training was 140 kV compared with 120 kV after training, with an increase in the use of the 100 kV setting in all age groups.

The researchers pointed out that the use of these lower settings can create greater image noise. However, “both visual and quantitative analysis of image quality revealed greater noise in target brain areas with the lower-dose head CT protocols used after training, which, however, did not result in a perceived loss of diagnostic information for any of the items evaluated.”