Patient and staff radiation doses should be known by interventional cardiologists.

1 In the European Council Directive 97/43 EURATOM on health protection of individual against the dangers of ionising radiation in relation to medical exposure1 interventional procedures are considered as a “special practice” involving high radiation doses to patients and requiring quality assurance programmes including patient dose evaluations. Practitioners performing such procedures shall obtain appropriate training in radiation protection (RP) under the responsibility of the Member States of the European Union (EU). The Directive mentions that the use of diagnostic reference levels (DRL) shall be promoted, and that Member States shall ensure that appropriate local reviews are undertaken whenever DRLs are consistently exceeded and that corrective actions are taken where appropriate. Staff working with ionising radiation are under the jurisdiction of specific national regulations coming out of the Council Directive 96/29/EURATOM2, requiring strict annual limits of doses, which do not apply to patients. The medical purpose of the procedure is considered a priority, and practitioners are expected to have enough knowledge of RP to avoid giving unnecessary radiation doses to the patients. DRLs are values that represent the state of practice and are only applicable to a sample of patients. In practice, the values are selected on the basis of a percentile point based on the observed distribution of doses to patients. The International Commission on Radiological Protection (ICRP) has introduced this concept in 1996 to help with the optimisation of medical exposures. In medical imaging, these values help indicate whether, in routine conditions, the levels of a patient’s dose are unusually high or low for a specified imaging procedure. If so, a local review should be initiated to determine whether protection has been adequately optimised or whether corrective action is required. The values should be selected by professional medical bodies in conjunction with national health and radiological protection authorities and reviewed at intervals that represent a compromise between the necessary stability and the long-term changes in the observed dose distributions3. In the beginning, DRL were only used for simple diagnostic examinations, but a significant effort has been made over the last years to extend this concept to interventional procedures and especially to cardiology. In 2003, a research consortium, supported by the European Commission, published a set of provisional DRL values for cardiology4. At the same time, the International Atomic Energy Agency (IAEA) launched an ambitious programme of RP in cardiology, including the preparation of a significant amount of training material5 and several research programmes dealing with the evaluation of patient doses as part of its International Action Plan on the radiological protection of patients. As a result, a pilot study involving hospitals from Europe, South America and United States, produced a second set of DRLs6 compatible with the previous European ones. Table 1 summarises the results obtained by the EU and the IAEA studies.