teleradiology because it necessitates clinical examination of the patient, including palpation. 2.5.1.2 Dental radiodiagnosis Intra-oral radiography Intra-oral radiography generators, which are usually mounted on an articulated arm, are used to take localised planar images of the teeth (the radiological detector is placed in the patient’s mouth). They operate with low voltage and current and a very short exposure time, of a few hundredths of a second. This technique is usually associated with a digital system for processing and filing the radiographic image. Panoramic dental radiography Panoramic radiography (orthopantomography) gives a single picture showing both jaws in full, by rotating the radiation generating tube around the patient’s head for a few seconds. Cone-beam computed tomography Cone-beam computed tomography (3D) is developing very rapidly in all areas of dental radiology, due to the exceptional quality of the images produced (spatial resolution of about 100 microns). The trade-off for this better diagnostic performance is that these devices deliver significantly higher doses than in conventional dental radiology. They must be used in accordance with the recommendations given by the HAS in 2009, the conclusions of which indicate that it should only be proposed in certain duly selected clinical indications and reiterate that whatever the case, the fundamental principles of justification and optimisation must be applied. 2.5.2 Technical layout rules for medical and dental radiodiagnosis facilities Radiology facilities A conventional radiological facility usually comprises a generator (high-voltage unit, X-ray tube), associated with a support (the stand) for moving the tube, a control unit and an examination table or chair. Mobile facilities, but which are routinely used in the same room, such as the X-ray generators used in operating theatres, are to be considered as fixed facilities. Radiological facilities must be fitted out in accordance with the provisions of ASN resolution 2017-DC-0591 of 13 June 2017. This resolution applies to all medical radiology facilities, including computed tomography and dental radiology. It does not however apply to X-ray generators that are used exclusively for bedside radiography and excluding any use in fluoroscopy mode. A technical report demonstrating conformity of the facility with the requirements of the ASN resolution must be drawn up by the person or entity responsible for the nuclear activity. Portable electrical devices generating X-rays ASN and the Dental Radiation Protection Commission (CRD) published an information notice in May 2016 reiterating the rules associated with the possession and utilisation of portable X-ray generating devices. “The performance of radiological examinations outside a room fitted out for that purpose must remain the exception and be justified by vital medical needs, limited to intraoperative examinations or for patients who cannot be moved. Routine radiology practice in a dental surgery equipped with a compliant facility shall not be carried out using mobile or portable devices”. This position is consolidated by that adopted by the Heads of the European Radiological protection Competent Authorities – HERCA), for which the use of such devices should be reserved for invalid patients, for the forensic medicine sector and for military personnel in the field of action (Position statement on use of handheld portable dental X-ray equipment – HERCA, June 2014). 2.5.3 Radiation protection situation: focus on the computed tomography scanner In France, medical applications represent the primary source of artificial exposure of the public to ionising radiation, chiefly due to CT examinations (see chapter 1). Imaging examinations have proven their benefits for both diagnosis and treatment. The issue at stake however is to avoid examinations that are not really necessary or that offer no real benefit for the patients and the results of which could be obtained by other available, nonirradiating techniques. In order to control the increase in doses observed over these last few years, two successive dose control plans (see chapter 1) have been developed in recent years. Issued in this context, ASN resolution 2019-DC-660 of 15 January 2019 relative to quality assurance in medical imaging contributes to the control of doses by requiring operational implementation of the justification and optimisation principles. Each year, ASN conducts about twenty inspections in computed tomography, adopting a graded approach by targeting the Accident & Emergency (A&E) departments (most often shared with the radiology department) and the paediatric CT scanners because of the vulnerability of the population concerned. Numerous ESRs occur in CT examinations in the A&E departments and are caused by poor communication or organisation between the A&E staff and radiology. The inspections conducted by ASN focus in particular on the verification of proper application of the requirements defined by ASN resolution 2019-DC-0660 of 15 January 2019 relative to quality assurance in medical imaging, especially the justification of the examinations and optimisation of the procedures. The majority of the inspected departments moreover have recourse to teleradiology to ensure Out-Of-Hours (OOH) service. The activity carried out in this context also enters into the checks performed in inspections. In 2022, ASN carried out 19 inspections in the area of computed tomography. Despite gradual implementation of the requirements of ASN resolution 2019-DC‑660 of 15 January 2019, improvements are expected in applying quality assurance methods to the justification principle for patients at risk (vulnerable patients, children, pregnant women, etc.) in order to improve the traceability of examination referral verifications at the various stages (reception, preliminary analysis, validation, alternative non-irradiating procedure, non-performance of procedure) and in formalising the specific work task qualification for medical staff. Alongside this, the ASN inspectors observe that departments are turning increasingly to teleradiology, sometimes leading to organisational difficulties (communication between software applications, delegation of tasks). Furthermore, 27 of the 219 ESRs in computed tomography reported to ASN (> 10%) occurred in teleradiology situations and were linked to communication problems between the medical professionals on-site and those working remotely. An analysis of events of this type will be conducted in 2023. 232 ASN Report on the state of nuclear safety and radiation protection in France in 2022 • 07 • Medical uses of ionising radiation 07
RkJQdWJsaXNoZXIy NjQ0NzU=