Establishing Diagnostic Reference Levels for Paediatric CT Imaging: A Multi-Centre Study

Background: Computed Tomography (CT) imaging is widely recognised for its high capability in assessing multiple organs. However, concerns about patient radiation exposure, particularly in children, pose significant challenges. Objective: This study aimed to establish diagnostic reference levels (DRLs) for paediatric patients in the most common CT examinations to monitor and better control radiation doses. Methods: Dosimetry records from 5956 patients' scans for the four most common CT imaging examinations-Head, Chest, Abdomen Pelvis (AP), and Chest Abdomen Pelvis (CAP)-were considered. The CT dosimetric quantities (CT dose-index volume (CTDI_vol) and dose-length product (DLP)), along with patient demographics (age and weight), were collected from radiology data storage systems. DRLs for CTDI_vol and DLP were determined for each imaging examination, stratified by patient age and weight groups, in accordance with ICRP recommendations. Results: The derived DRLs are presented as [median CTDI_vol (mGy): median DLP (mGy·cm)]. For (<1 yr): Head: 13:187, Chest: 0.4:7, AP: 0.9:19, CAP: 0.4:10. For (1-5 yrs): Head: 16:276, Chest: 1:22, AP: 1.5:58, CAP: 1.6:63. For (6-10 yrs): Head: 19:332, Chest: 1.4:35, AP: 1.9:74, CAP: 2:121. For (11-15 yrs): Head: 21:391, Chest: 3:86, AP: 4.1:191, CAP: 3:165. We observed that both the CTDI_vol and DLP DRL values increase with patient age. Weight-based DRLs follow similar trends for CTDI_vol, while DLP values show noticeable variations in Chest and AP examinations. Conclusions: The study findings highlight the need for review and optimisation of certain scanning protocols, particularly for chest and AP examinations. The derived DRLs are consistent with findings from other studies. The study recommends establishing national paediatric DRLs to enhance radiology practice across the country and ensure adherence to international safety standards.