Cardiac-gated CTA radiation doses can vary and be as high as 28.4 mSv (10 times the annual natural background radiation) in children, according to a recent study conducted by researchers from Duke University Medical Center in Durham, NC and Stanford University Medical Center in Palo Alto, CA.
"This investigation evaluated the potential radiation dose of coronary CT angiography in pediatric patients," said Caroline Hollingsworth, MD of Duke University Medical Center, lead author of the study. "Since often adult technologies and techniques are simply applied to children, we were interested in assessing what the dose could be," she said.
"Technical advances in multidetector CT angiography have lead to increased utilization of this technology for evaluation of the coronary arteries in adults. However, this technology lacks systematic assessment in children," said Dr. Hollingsworth. "Due to concerns for potentially large radiation doses from this type of CT evaluation, we were interested in assessing standard gated coronary CTA techniques in a pediatric phantom. Dosimetry information is important since optimal techniques for this type of coronary assessment are still under evolution as this technology becomes increasingly utilized," she said.
For the study, an ECG-gated cardiac CTA simulating scanning of the heart was performed on a phantom of a 5-year-old child on a 16-MDCT scanner. The highest doses were of the breast (3.5-12.6 cGy), lung (3.3-12.1 cGy) and bone marrow (1.7-7.6 cGy). To put these numbers into perspective, 12 cGy is equivalent to about 50 two-view screening mammograms.
"The results of this investigation support that coronary CTA doses vary substantially with different parameters and can provide very high radiation doses to children when adult-type parameters are utilized," said Dr. Hollingsworth. "Optimal techniques in children have yet to be developed and the results of this study show that gated CTA should be used cautiously in the pediatric population while further evaluation of newer techniques (modulation), applications and outcomes are evaluated," she said.
The full results of this study appeared in the July issue of the American Journal of Roentgenology, published by the American Roentgen Ray Society.