Computed Tomography Diagnostic Reference Levels Worldwide and in Jordan: Implications for Patient Dose Reduction

Computed tomography (CT) contributes substantially to medical radiation exposure, making diagnostic reference levels (DRLs) essential for dose optimization and patient protection. This narrative review summarizes international CT DRL practices and examines the current status of DRL development in Jordan. Published studies and key guidance documents addressing adult and pediatric CT DRLs, including CTDIvol, dose-length product (DLP), and size-specific dose estimate (SSDE) where available, were reviewed to identify common implementation approaches, frequently used dose metrics, and evidence gaps relevant to Jordan. The reviewed literature shows marked inter-country variation in DRL methodology, updating cycles, and regulatory integration. In Jordan, available studies demonstrate useful local and multicenter data, but routine CT practice still lacks a unified national DRL framework. Reported Jordanian values also show inter-institutional variability, highlighting the need for standardized data collection, regular auditing, and coordinated national oversight. Establishing national DRLs based on transparent methodology and periodic revision would strengthen radiation protection, improve protocol consistency, and support safer CT practice in Jordan.