ASN Report 2017

277 ASN report on the state of nuclear safety and radiation protection in France in 2017 Chapter 09  - Medical uses of ionising radiation The prevention of risks of exposure of health professionals to ionising radiation is required by provisions of the Labour Code concerning occupational radiation protection. 5.1.2 Exposure of patients The exposure of patients to ionising radiation must be distinguished from the exposure of workers and the public insofar as it is subject to no dose limits whatsoever. Only the principles of justification and optimisation are applicable (see chapter 3). The patient’s exposure situation differs depending on whether diagnostic or therapeutic medical applications are being considered. In the first case, it is necessary to optimise the exposure to ionising radiation in order to deliver the minimum dose required to obtain the appropriate diagnostic information or to perform the planned interventional procedure; in the second case, it is necessary to deliver the highest possible dose needed to destroy the targeted cells while at the same time preserving the healthy neighbouring tissues to the best possible extent. Whatever the case however, control of the doses delivered during imaging examinations and treatments is a vital requirement that depends not only on the skills of the patient radiation protection professionals but also on the procedures for optimising and maintaining equipment performance. Controlling doses remains a priority for ASN which, following on from the first plan initiated in 2011, drew up a second plan in 2017 in order to continue promoting a culture of radiation protection with the professionals (see chapter 1). 5.1.3 Exposure of persons providing support and comfort to patients The persons close to patients having been treated with radiopharmaceuticals (e.g. treatment of thyroid cancer or hyperthyroidism with iodine-131) can be exposed to ionising radiation for a few days due to the residual activity in the patient. In 2016, ASN asked IRSN (Institute of Radiation Protection and Nuclear Safety) to issue recommendations for setting dose limitations for persons providing support or comfort to patients during their medical diagnosis or treatment. The GPMED (Advisory Committee for Radiation Protection in Medical and Forensic Applications of Ionising Radiation) gave its opinion on these recommendations in 2017; the recommendations were forwarded to the SFMN in order to update the existing good practice recommendations. 5.1.4 Exposure of the general public and environmental impact With the exception of incident situations, the potential impact of medical applications of ionising radiation is likely to concern: ཛྷ ཛྷ members of the public who are close to facilities that emit ionising radiation but do not have the required protection; ཛྷ ཛྷ persons close to patients having received a treatment or a nuclear medicine examination, particularly those using radionuclides such as iodine-131, or a brachytherapy with iodine-125; ཛྷ ཛྷ the specific professional categories (e.g. sewage workers) liable to be exposed to effluents or waste produced by nuclear medicine units. The available information concerning radiological monitoring of the environment carried out by IRSN, in particular the measurement of ambient gamma radiation, on the whole reveals no significant exposure level above the variations in the background radiation. On the other hand, radioactivity measurements in major rivers or wastewater treatment plants in the larger towns occasionally reveal the presence of artificial radionuclides used in nuclear medicine (e.g. iodine-131) exceeding the measurement thresholds. The available data on the impact of these discharges indicate doses of a few tens of microsieverts per year for the most exposed individuals, particularly people working in sewerage networks and wastewater treatment plants (source: IRSN studies, 2005 and 2014). Furthermore, no trace of these radionuclides has ever been measured in water intended for human consumption (see chapter 1). FOCUS Patient radiation protection actions taken by HERCA The question of justification in the medical sector is a priority issue for HERCA. Several meetings have been organised since 2016, bringing together the various stakeholders, whether European (European societies of radiology, nuclear medicine, radiographers, representatives of equipment suppliers and manufacturers, the European Commission), international (the International Atomic Energy Agency – IAEA, the World Health Organisation – WHO, the International Society of Radiographers) or French. The conclusions of a seminar organised by HERCA and held at ASN in October 2016 were published in 2017 ( www.herca.org ). In November 2016 HERCA also organised a week of inspections targeting implementation of the principle of justification in medical radiology. The conclusions of this joint European initiative were presented at the international conference on radiation protection in medicine organised by the IAEA and held in Vienna in December 2017. In addition to this, in November 2017 HERCA published the conclusions of several years of work in collaboration with the COCIR (European Coordination Committee of the Radiological, Electromedical and Healthcare IT Industry) concerning dose optimisation in computed tomography. This 2107 report ( www.herca.org ) presents the advances in four subjects committed to by the COCIR and the main CT scanner manufacturers: the characterisation of CT scanner performance, the implementation of dose reduction tools, dose management and training.

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