In recent decades, survival among patients with congenital heart disease (CHD) has increased considerably, to the point that there are currently more adults than children living with CHD. With increasing life expectancy, new health concerns have come into focus, including the potentially long-term carcinogenic risks of exposure to low-dose ionising radiation (LDIR) from cardiac diagnostic and therapeutic procedures, particularly those related to cardiac catheterisation in children. Studies from non-medical contexts—atomic bomb survivors and uranium mine workers, among others—have clearly linked LDIR exposure with a higher risk of subsequent malignancy. Many organisations monitoring the use of radiation-emitting technologies—including the US National Research Council's Biological Effects of Ionizing Radiation (BEIR VII) Committee, the International Commission on Radiological Protection and the US National Council on Radiation Protection and Measurements—endorse a ‘linear no-threshold’ model for LDIR-related malignancy risk. That is, even at the lower doses typically encountered in medical settings, LDIR would be expected to confer some carcinogenic risk, although that risk could be imperceptibly low unless large populations are examined. Indeed, with larger cohorts being assembled around these questions, there is an emergence of evidence to suggest that contemporary medical sources of LDIR likely also confer cancer risk.1 ,2

Of concern is the observation that the use of LDIR-emitting cardiac procedures in patients with CHD is increasing on a population level, with exposure occurring at progressively younger ages.3 This is of particular concern, since children have immature and developing organs and tissues with higher rates of cell division, and thus greater potential for mutagenesis following LDIR exposure. Exposure to LDIR at younger ages is known to be associated with higher risks of …