Comparison of organ absorbed doses in whole-body computed tomography scans of paediatric and adult patient models estimated by different methods

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.