To develop diagnostic reference ranges (DRRs) for pediatric abdominopelvic dual-energy (DECT) examinations as a function of patient size and radiation output of the CT scanner with comparison to conventional CT.

Volume CT dose index (CTDIvol) and effective diameter of pediatric patients (mean age 9.3±5.9 years) who underwent contrast-enhanced abdominopelvic CT with either conventional CT (N=1719) or dual-energy CT (N=375 patients) on a dual-source CT system (Somatom Flash, Siemens) from September 01 2014 to March 01 2018 were retrieved from our institutional dose tracking system (Radimetrics). All conventional CT scans used automatic tube potential selection (ranging from 70 to 120 kVp). Both conventional and DECT acquisitions used automatic exposure control and iterative reconstruction. Patient data were grouped into one of five effective diameter ranges to allow developments of DDRs as a function of patient size. The median, 25th and 75th quartile of the two CT dose indexes were determined for the corresponding effective diameters. Statistical unpaired comparisons were made between groups.

For the five effective diameters (<15cm, 15-19cm, 20-24cm, 25-30cm and >30cm), the median DRRs [25-75th quartile] for CTDIvol for conventional and DECT were 3.7[2.7-3.4] mGy and 2.6[2.4-2.8]mGy (P>.05); 3.6[3.2-3.8]mGy and 3.3[3.0-3.7] mGy (P>.05); 4.8[4.0-6.1])mGy and 4.7[4.3-5.5]mGy (P>.05); 7.1[6.2-8.3]mGy and 6.5[5.8-7.4]mGy (P<.01); 11.4[10.0-14.4]mGy and 9.8[8.9-11.8] mGy (P<.05). There was no statistically significant difference in CTDIvol between conventional and DECT for effective diameters below 25cm. CTDIvol of DECT in patients with effective diameters >25cm was significantly lower than that of conventional CT.

The DRRs for pediatric abdominopelvic DECT reported in this study as a function of patient size and radiation output can serve as reference standards to help manage pediatric patient radiation doses in DECT. The radiation doses are comparable or lower than those of conventional CT.

DRRs for pediatric abdominopelvic DECT based on CTDIvol and body size may allow other imaging sites to implement DECT in clinical practice and reduce pediatric patient doses.