2.5.1.1 Medical radiodiagnosis Conventional radiology Conventional radiology (producing radiographic images, or radiographs), if considered by the number of procedures, represents the large majority of radiological examinations performed. The examinations mainly concern the bones, the thorax and the abdomen. Conventional radiology can be carried out in fixed facilities reserved for diagnostic radiology or, in certain cases, using portable devices if justified by the clinical situation of the patient. Angiography This technique, used for exploring blood vessels, involves injecting a radio-opaque contrast agent into the vessels which enables the arterial (arteriography) or venous (venography) tree to be visualised. Angiography techniques benefit from computerised image processing (such as digital subtraction angiography). Mammography Given the composition of the mammary gland and the fineness of detail required, screening for breast cancer necessitates the use of mammography units, specific radiology devices providing high-definition and high-contrast images. Two complementary imaging techniques are currently available, planar imaging (2D) and tomosynthesis imaging (3D). Only planar imaging, which functions at low voltage and offers high definition and high contrast, is at present approved by the HAS for breast cancer screening. ASN participated in a working group coordinated by the HAS, which has assessed the position of tomosynthesis mammography in the breast cancer screening strategy. In 2019, the HAS published a first report on the technical performance of tomosynthesis mammography in breast cancer screening of average-risk women. A second report on the evaluation of the performance and the position of tomosynthesis mammography in the French organised breast cancer screening programme was published by the HAS in April 2023. It recommends integrating tomosynthesis mammography (3D) in the organised screening programme, on condition that it is always 2D synthetic image reconstruction (2Ds) in order to improve the screening performance without increasing the dose of ionising radiation. The use of these devices is subject to quality controls defined by the ANSM. The planar imaging (2D) quality controls are defined by the ANSM resolution of 15 January 2020 which entered into effect on 15 January 2021. ASN was consulted in this context and gave a favourable opinion on the draft resolution relative to the internal and external quality controls of digital mammography facilities. This resolution is currently being updated. The future resolution will update the checks performed on 2D mammography units and will introduce external quality controls for the tomosynthesis devices. ASN has asked the GPRP to update the collection methods and the DRLs for 2D-DR mammography and to establish them for tomosynthesis mammography. The opinion given by the GPRP in June 2023 will allow the updating of ASN resolution 2019‑DC‑0667 of 18 April 2019 on the methods of evaluating ionising radiation doses delivered to patients during radiology, FGIP or nuclear medicine procedures and the updating of the associated DRLs. Computed tomography Computed Tomography (CT) scanners use a beam of X-rays emitted by a tube that rotates around the patient’s body as the bed moves linearly, describing a helical scan. These scanners produce a three-dimensional reconstruction of the organs with very much 12. The term “indication” means a clinical sign, an illness or a situation affecting a patient which justifies the value of a medical treatment or a medical examination. better image quality than that of conventional radiology devices. An examination can comprise multiphase image acquisitions on the same given anatomical location or on different anatomical regions. This technique can, like MRI, be associated with functional imaging provided by nuclear medicine in order to obtain fusion images combining functional information with structural information. The technologies developed over the last few years (such as multienergy photon-counting CT scanners) have made examinations easier and faster to perform, and have led to an increase in exploration possibilities (example of dynamic volume acquisitions) and in the indications(12). The placing of mobile CT systems on the market for intraoperative use is to be underlined, as is the increase in fluoroscopy-guided interventional CT procedures. On the other hand, these technological developments have led to an increase in the number of examinations, resulting in an increase in the doses delivered to patients and thus reinforcing the need for strict application of the principles of justification and optimisation (see point 1.3.4). Technical progress has nevertheless brought a new mode of image reconstruction in the form of iterative reconstruction. CT can thus provide consistent image quality at reduced doses. The devices can also be equipped with dose-reduction tools. Strict application of the principles of justification of the procedures and optimisation of the protocols remains as topical as ever. Teleradiology Teleradiology is a remote medical practice of radiological medicine that essentially concerns conventional radiology and computed tomography and provides the possibility of performing and remotely interpreting radiological examinations. Essentially two methods are used: ∙ Telediagnosis allows the performance of a synchronous imaging procedure. The question asked and the reply, if the patient is not present, do not necessarily take place simultaneously or synchronously. The radiographer takes charge of the patient to perform the radiological or CT examination after receiving the instructions from the teleradiologist. At the end of the examination, the images are sent to the teleradiologist in order to formalise a results report in a manner comparable with what an on-site radiologist would have done. ∙ Tele-expertise enables a medical professional to request from a distance, by e-mail or any other secure communication tool, the opinion of one or more medical professionals in a given medical situation. Teleradiology is a medical procedure defined in the Public Health Code that is more than just a remote interpretation of images. Its development is becoming more widespread to allow continuity of out-of-hours service and to reduce the waiting times before receiving medical care. The organisation of the practice, the way it interfaces with the personnel on site and the many responsibilities are specified by contract between the healthcare facility and the teleradiology service provider. In May 2019 the HAS published a Guide to good practices concerning the quality and safety of tele-imaging procedures. Details are provided, with organisational, technical and operational recommendations. The French Professional Council of Radiology and Medical Imaging (G4) and the French Council of the Order of Physicians jointly published a teleradiology charter in February 2020, containing nine general recommendations. Lastly, the G4 also drafted baseline requirements for the profession and the skills of the radiologist in January 2023. It reinforces the 234 ASN Report on the state of nuclear safety and radiation protection in France in 2023 • 07 • Medical uses of ionising radiation
RkJQdWJsaXNoZXIy NjQ0NzU=