[en] This study examines the kerma-area product (P_KA) levels from paediatric cardiac catheterizations at a major Children's Hospital over three different time periods in order to gain an understanding of the causation of dose variations over time and to present a model for dose reduction. A retrospective review of 1245 paediatric procedural records was undertaken. This cohort consisted of patients that were catheterised over a period from November 2007 to July 2009, October 2009 to November 2011 and January 2016 to December 2016. The age distribution was from newborn to 18 years. Archived (P_KA) readings were retrieved and analysed. The 75. percentile P_KA values for the specific age categories over time periods (1, 2, 3) were 0-30 days-(5.47, 1.37, 1.37) Gy cm²; 1-12 months-(6.42, 2.03, 1.06) Gy cm²; 1-3 years-(11.25, 3.20, 1.25) Gy cm²; 3-5 years-(12.65, 3.72, 2.88) Gy cm²; 5-10 years-(12.80, 8.53, 3.52) Gy cm²; 10-15 years-(27.92, 10.85, 2.97) Gy cm²; >15 years-(29.09, 27.81, 11.65) Gy cm². Using newer imaging technologies, optimising dose reduction strategies and regular dose auditing can transform radiation dose delivery for paediatric x-ray examinations. Our centre provides a template for dose reduction success worldwide. (authors)