Radiation dose to premature new-borns in the Belgian Neonatal Intensive Care Units

In the neonatal intensive care units (NICUs), premature new-borns may receive important dose over a short period. Because of their intrinsically greater radiosensitivity and their longer life-expectancy, dose optimisation is of particular concern. Within this framework, the present study aimed at proposing national diagnostic reference levels (DRLs) for the most common examinations in premature patients, the radiographs of the chest. Entrance surface dose (ESD), Kerma area product (KAP) and organ doses were considered. Since large differences in size are frequent in premature new-borns, the DRLs were also established for different weight categories. ESDs were calculated from exposure settings and tube measurements. The study was successfully carried out in half of the Belgian NICUs. Wide variations were observed between the centres as well for ESDs (median of 13–70 µGy) as for KAP (median of 1.1-7.4 mGy.cm²) and organ doses. Those observations were explained by large variations in the examination settings. The dose per radiograph was usually low (below the EC and NRPB reference levels), but the cumulated dose per stay could be high. In addition, the wide intercentre variation indicates that the doses could be minimised. The use of DRLs should contribute to achieve this objective.