Comparison of Organ Absorbed Doses in Whole-Body Computed Tomography Scans of Paediatric and Adult Patient Models Estimated by Different Methods

Abstract

This study aimed to identify the uncertainty in estimations of organ absorbed dose using dedicated software by comparing with corresponding doses measured in physical phantoms. The comparison was performed for whole-body computed tomography (CT) obtained as part of positron emission tomography. Whole-body CT scans provide an advantage in terms of comparison because all organs are in the primary beam of the irradiated area. Organ doses estimated by the different software programs (CT-Expo, VirtualDose and NCICT) were compared by thermoluminescent detector measurements in anthropomorphic phantoms in 1-y-old, 5-y-old and adult patients. Differences were within ~15% in 12 major organs. However, differences of ~30% were observed in organs located at slightly different positions in the computational models compared to the physical phantoms. All investigated programs were deemed suitable for accurate estimation of organ absorbed dose.

Comparison of organ and effective dose estimations from different Monte Carlo simulation‐based software methods in infant CT and comparison with direct phantom measurements

“…Doses to skeletal tissues and effective doses were not evaluated in that study. 24 Although whole-body CT acquisitions in infants are currently limited to a few applications, [41][42][43] the CTDI vol normalized data presented in this study can easily be implemented to assess the doses to primary beam organs most at risk during infant examinations that…”

“…When normalizing organ doses to CTDI vol , most organ doses align with measurement uncertainty between the studies. Doses to skeletal tissues and effective doses were not evaluated in that study 24 …”

“… 21 , 22 , 23 These have been attributed to variation in anatomy between phantoms and variation in scanner‐matching methods between software programs. However, there have been limited studies assessing pediatric phantoms, 12 , 24 , 25 with no studies published evaluating the accuracy of the dosimetry software for skeletal tissue or effective dose estimates in CT examinations involving 1‐year olds. The objective of this study was to compare the different software for CT primary organ dosimetry and effective dose estimation and to assess their accuracy for clinical application in a 1‐year‐old infant.…”

Cumulative radiation dose from medical imaging in paediatric congenital heart disease patients with epicardial cardiac implantable electronic devices

“… 17 CT doses calculated using the publicly available National Cancer Institute (NCI) dosimetry software have been shown to align with TLD values within 8–20%, particularly in infants and children, 18–20 and produce similar results to other virtual phantoms. 21 Therefore, for this retrospective study, all ED doses were calculated using the NCI dosimetry software.…”