Regional diagnostic reference levels in paediatric interventional cardiology: methodological comparison of ICRP Publication 135 approaches using OPRIPALC data

values assumed to represent typical country values. DRLs were established using predefined age and weight groups. Both methodologies preserved the expected increase in DRL values with patient age, weight and procedural type. However, Method A consistently produced higher regional DRL values than Method B, particularly for therapeutic procedures and higher age or weight categories. These differences reflect the effects of data aggregation rather than differences in the underlying dataset. This study aims at illustrating the practical implications of one method over the other, rather than to recommend one methodology over the other. The findings highlight the importance of methodological transparency in regional DRL initiatives and support the applicability of the OPRIPALC framework for paediatric interventional cardiology in other regions.