Evolution of diagnostic reference levels in paediatric cardiac interventional procedures: a narrative review

The goal of this narrative review was to identify and synthesise publications reporting radiation dose values for paediatric cardiac interventional procedures (PCIP), organised according to four DRL-related benchmarking levels used in this review: typical values, local DRLs, national DRLs and regional DRLs. These procedures can deliver high radiation doses to markedly radiosensitive patients. DRLs are an important tool for optimising these exposures. Publications from 2010 to 2025 were searched, and twenty-five studies met the eligibility criteria, with reported kerma-area product (P_KA) taken as a common comparator. Reported P_KA spanned more than two orders of magnitude, from below 1 Gy cm² in patients under 5 kg to above 100 Gy cm² for complex therapeutic procedures in larger children. Within a single DRL category, procedural complexity alone drove differences exceeding one order of magnitude, while procedure-specific stratification converged on a narrow 1-5 Gy cm² band in the youngest patients. National DRLs showed the widest inter-study dispersion and regional DRLs the narrowest. The variability in reported dose values was primarily driven by differences in categorisation schemes and procedural complexity rather than by inconsistencies in the DRL concept itself. The available evidence reflects an evolution from early local initiatives towards national and regional frameworks characterised by increasing methodological maturity and international collaboration. Future developments are expected to move towards complexity-based DRLs supported by large multicentre datasets, automated dose monitoring and artificial intelligence for real-time optimisation, while coordinated regional initiatives and shared registries may enable continuous DRL updating and stronger radiation protection for PCIP.