Differences in using the international commission on radiological protection's publications 60 and 103 for determining effective dose in paediatric CT examinations

The use of computed tomography (CT) worldwide is continuing to increase for both adults and children, posing population health risks due to radiation exposure. These risks are highest for children, reducing with age at exposure. Effective dose is a useful parameter for expressing relative risk and comparing dose. In this study, high sensitivity thermoluminescence dosemeters (TLD) were used to measure organ absorbed doses and to calculate effective dose for paediatric CT examinations of the brain, chest and abdomen/pelvis. Formalisms recommended by the International Commission on Radiological Protection (ICRP) in Publications 60 and 103 were assessed. The effective dose computed using ICRP 103 was 22% lower for a CT brain examination, 16% higher for a CT chest examination and 4% lower for a CT abdomen/ pelvis examination when compared with the effective dose computed using ICRP 60. These values were compared with effective dose calculated using a dose length product (DLP) conversion method. The DLP derived effective doses were within 30% of the TLD derived effective doses. In summary, the effective dose varies depending on the ICRP de?nition used, predominantly due to changes in tissue weighting factors. Furthermore, the DLP conversion method is relatively reliable for approximating effective dose and easy to use.