Radiation dose levels in pediatric chest CT: experience in 499 children evaluated with dual-source single-energy CT.

Abstract

The availability of dual-source technology has introduced the possibility of scanning children at lower kVp with a high-pitch mode, combining high-speed data acquisition and high temporal resolution. To establish the radiation dose levels of dual-source, single-energy chest CT examinations in children. We retrospectively recorded the dose-length product (DLP) of 499 consecutive examinations obtained in children <50kg, divided into five weight groups: group 1 (<10kg, n = 129); group 2 (10-20kg, n = 176); group 3 (20-30kg, n = 99), group 4 (30-40kg, n = 58) and group 5 (40-49kg, n = 37). All CT examinations were performed with high temporal resolution (75ms), a high-pitch mode and a weight-adapted selection of the milliamperage. CT examinations were obtained at 80kVp with a milliamperage ranging between 40mAs and 90mAs, and a pitch of 2.0 (n = 162; 32.5%) or 3.0 (n = 337; 67.5%). The mean duration of data acquisition was 522.8 ± 192.0ms (interquartile range 390 to 610; median 490). In the study population, the mean CT dose index volume (CTDIvol32) was 0.83mGy (standard deviation [SD] 0.20mGy; interquartile range 0.72 to 0.94; median 0.78); the mean DLP32 was 21.4mGy.cm (SD 9.1mGy.cm; interquartile range 15 to 25; median 19.0); and the mean size-specific dose estimate (SSDE) was 1.7mGy (SD 0.4mGy; interquartile range 1.5 to 1.9; median 1.7). The DLP32, CTDIvol32 and SSDE were found to be statistically significant in the five weight categories (P < 0.0001). This study establishes the radiation dose levels for dual-source, single-kVp chest CT from a single center. In the five weight categories, the median values varied 15-37mGy.cm for the DLP32, 0.78-1.25mGy for the CTDIvol32 and 1.6-2.1mGy for the SSDE.