Introduction: The introduction of Dual Source Single Energy CT (DSCT) scanners few years ago was an opportunity for development of lower dose protocols. We built a low-dose chest protocol using this novel technique to evaluate lung fields in children. Patients referred by pediatric pulmonologists for CT evaluation either for Cystic Fibrosis (CF) or Bronchiolitis Obliterans (BO) were scanned using this low-dose protocol. Balla score for CF was used to assess the diagnostic power of the images. We present the Rambam pediatric radiology experience with this low-dose protocol, along with its impact on clinical care of patients in the pediatric pulmonology unit.
Purpose: To assess the reduction in radiation doses using low- dose chest DSCT protocol for CF and BO pediatric patients, and to assess the diagnostic feasibility using Balla score.
Methods: Chest CT scans of either CF (n=46) or BO (n=25) in pediatric patients aged 0-20 years performed at our institute using the DSCT from September 2013-July 2017 were collected. Radiation effective dose was calculated using dose length product (DLP) and age related factor. Two pediatric radiologists calculated Balla score for all scans in agreement. The ability to calculate the score was used as a threshold for image quality.
Results: The median effective dose in all chest CT scans was 0.49 mSv demonstrating at least 84% reduction compared to typical effective dose of pediatric chest CT scan according to the Israeli Ministry of Health. Median DLP in the 0-5-year age group demonstrated 95% reduction compared to the DLP reported for this age group by the National Radiological Protection Board in the UK. A similar 95% and 94% reduction was noted in the 5-10, and 10-15 year age groups respectively. Moreover, CT dose index (CTDIvol) demonstrated 96%, 96%, and 91% reduction in the 0-5, 5-10, 10-15-year-old age groups respectively compared to CTDIvol reported for the corresponding age group in the aforementioned British study.
Conclusion: CT is an extremely important diagnostic tool, yet carries a toll of radiation risk burden. Our study revealed that a low dose chest protocol using DSCT led to significant reduction in effective dose and other radiation parameters (DLP and CTDIvol) compared to the Israeli Ministry of Health recommendations and worldwide literature using traditional CT scanning techniques. The low-dose yet diagnostic study changed the clinical practice in pediatric pulmonology unit and improved patient care.
