Analysis of paediatric ct head radiation doses as an initiation to establish local diagnostic reference levels

Abstract

Background and objectives Most of the medical imaging modalities are based on use of ionizing radiation. Ionizing radiation carries the risk of tissue damage and radiation induced malignancy. Therefore, medical imaging should be done under optimal conditions. The purpose of this study was to perform an audit on computed tomography (CT) head radiation doses at the Lady Ridgeway Hospital Colombo (LRH), as an initiation to establish local diagnostic reference levels (LDRL) for the radiology department at LRH. Methodology Computed Tomography Dose Index (CTDI) and Dose Length Product (DPL) are the International Commission on Radiation Protection (ICRP) recommended radiation dose indicators for CT. The study was performed by retrospective analysis of CT head records over a period of 6 weeks. Data was collected according to patient’s age, grouped as <1 year, 1–5 years, 5-9 years and > 9 years. Mean and median for CTDI vol and DLP quantities in each age group were calculated. The median values were used to establish LDRL for the facility. Results LDRL values for CT head across the age groups are 30 to 57.2 mGy for CTDI vol and 535.5 to 1235 mGy cm for DLP. Conclusion LDRL values for CT head in all age groups at LRH are higher than international DRL values. The difference for DLP is higher than CTDI vol indicating higher scan length and/or higher number of multiphasic studies.