Doses from ionising radiation in paediatric cardiac catheterisations in Norway 1975–2021

Paediatric patients with congenital heart disease often undergo cardiac catheterisation procedures and are exposed to considerable ionising radiation early in life. This study aimed to develop a method for estimating the dose area product (<i>P</i>_KA) from paediatric cardiac catheterisation procedures (1975-1989) at a national centre for paediatric cardiology and to evaluate trends in<i>P</i>_KAand exposure parameters until 2021. Data from 2200 catheterisation procedures on 1685 patients (1975-1989) and 4184 procedures on 2139 patients (2000-2021) under 18 years of age were retrospectively collected.<i>P</i>_KAvalues were missing for 1975-1989 but available from 2000 onward. The missing<i>P</i>_KAwas estimated from air kerma and beam area, based on exposure records and input from clinicians working at that time.<i>P</i>_KAtrends were analysed over time and age. There was a 71% reduction in median<i>P</i>_KAfrom the period 1975-1989 (median 6.63 Gy cm²) to 2011-2021 (1.91 Gy cm²). The<i>P</i>_KAincreases significantly (<i>p</i>= 0.0001) with patient age, which was associated with body weight. Approximately 80% of the total<i>P</i>_KAwas from cine acquisition in 1975-1989, while 20% was from fluoroscopy. The<i>P</i>_KAestimate during 1975-1989 was considerably impacted by the assumptions of missing parameters such as tube filtration, focus-to-heart distance, beam area, and number of cine series. The decreasing trend in<i>P</i>_KAvalues was attributed to advancements in both technologies and clinical practices. The high contribution of cine acquisition to the total dose during 1975-1989 was due to factors such as a high frame rate, multiple acquisitions, and high tube current. The estimated<i>P</i>_KAvalues for the period 1975-1989 are of importance for the dose reconstruction and risk assessments in the EU epidemiology project Health Effects of Cardiac Fluoroscopy and Modern Radiotherapy in Pediatrics(HARMONIC).