An Age-Based Size-Specific Dose Estimate for Pediatric Computed Tomography Head Examinations Performed at Songklanagarind Hospital, Thailand, from 2017 to 2019

Abstract

Computed tomography (CT) is the primary source of diagnostic radiation in pediatric patients. Patient head size and tissue attenuation are critical factors for estimating CT radiation doses. This study aimed to determine a size-specific dose estimate based on the water-equivalent diameter (SSDEDw) for pediatric CT head examinations, categorized by age group, and to investigate the parameters influencing the SSDEDw. This retrospective analysis included 274 pediatric patients aged 0 to 15 years who underwent non-contrast CT head examinations using an age-based protocol without automatic exposure control systems. The SSDEDw was calculated using the CTDIvol, and the conversion factor was derived from AAPM Report No. 293, based on the water-equivalent diameter (Dw). We found that the SSDEDw of age groups of 0 to 6 months, 6 months to 3 years, 3 to 6 years, 6 to 12 years, and 12 to 15 years were 15.4 (14.8, 15.8), 20.1 (19.6, 20.6), 25.3 (24.6, 25.7), 28.1 (27.3, 28.8), and 35.1 (34.6, 36) mGy, respectively. Age and body weight significantly affected the SSDEDw, with high R-squared values of 0.87 and 0.63, respectively (p < 0.001). The SSDE, particularly when based on the water-equivalent diameter (SSDEDW), is a valuable supplement to the DLP and the CTDIvol as it closely relates to patient dose, especially for pediatric head scans of different patient sizes.