An audit on radiation dose received by the paediatric population undergoing CT investigations at the Wits Academic Hospitals

Van der Merwe, Cornelis M.
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Introduction: Diagnostic Reference Levels (DRL) is a crucial element of auditing radiation dosages in paediatric computed tomography (CT). Currently, there are no national paediatric CT DRLs in South Africa. Methods: Computed Tomography Dose Indexvolume (CTDIvol) and Dose Length Product (DLP) values were collected from paediatric CT examination done at two university hospitals, in patients aged 0 to 15 years. Four age groups were subcategorized. The 75th percentile of the data distribution was calculated for each CT examination type and age group and comparisons made using the quantile regression procedure. Results: During the retrospective audit from 1 November 2016 to 30 April 2017, a total of 1031 CT examinations were done. CT Brain examination was the most common examination done 755/1031 (72.23%), followed by CT of the abdomen 82/1031 (7.95%). There was increased DLP values in the afterhours categories at both hospitals with the largest increase compared to regular working hours in the age group 0-1 year (150.56%). In the 0-1-year age groups demonstrated higher values than expected for CT Abdomen and CT Chest. Discussion: The increased CTDIvol and DLP values for CT Abdomen and Chest in the 0-1-year group is most likely due to suboptimal protocols, and these should be reviewed. Strategies to limit radiation exposure in afterhours needs to be implemented. In comparison to international DRLs the radiation output levels compared favourably apart from the 0-1- year age category for CT Chest and CT Abdomen. Conclusion: CT body examination protocols for 0-1-year patients should be reviewed. In general, the proposed local DRLs compare favourably to international DRLs. The data of this study will be presented to the South African Society for Paediatric Imaging to aid in the establishment of national DRLs.
A research report submitted in fulfillment of the requirements for the degree of Masters of Medicine to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, 2019