The Sentinel Project

Full text: Introduction. The past two decades have witnessed a technology-driven revolution in radiology. At the centre of these developments has been the use of computing in diagnostic imaging. These developments have also been driven by the introduction of new detectors and imaging devices in radiology and nuclear medicine, as well as the widespread application of computing techniques to enhance and extract information from within the images acquired. However, these technological developments have not been matched by justification and optimization studies to ensure that these imaging devices and clinical techniques are as effective as they might be, or performed at the lowest possible dose. The SENTINEL coordination action covers radiation protection, safety and related issues that arise from the introduction of digital technologies. SENTINEL covers 90% of patient examinations, 60% of the collective dose from medical sources and approximately 50% of the collective dose to European citizens from man-made sources. SENTINEL covers all of digital imaging in radiology, with the exception of computed tomography scanning. The main objectives of the SENTINEL coordination action are: 1) Establish both physical and clinical image quality criteria, and link the two. 2) Perform a series of dosimetry studies to deduce reference levels. 3) Develop good practice guidelines for radiation protection and to publish training material. The SENTINEL consortium comprises 22 members from 16 Member States. These are complemented by partners from candidate Member States and international organisations. SENTINEL coordination action activities Justification and optimization form the basic elements for the radiological protection of individuals in the case of medical exposures. Justification includes the development of referral criteria. Medical exposure for diagnostic applications is only justified in the case of a sufficient net benefit. This has its origins in the Hippocratic Oath, which most doctors swear, and may be summarized as doing more good than harm. In the case of medical exposures, this implies that the patient doses should be relatively low to restrict the detriment caused by ionizing radiation, whereas image quality should be sufficient to allow potential diagnostic benefits. According to the Medical Exposures Directive, diagnostic reference levels should be established and used as an aid to optimization. This process is ongoing within the European Union Member States. Optimization should result in improved image quality at equal or lower dose to the patient or in a dose reduction at an image quality sufficient for obtaining diagnostic information. The Medical Exposures Directive places special attention to the medical exposure of children, exposures received as part of a health screening programme, such as mammography and examinations involving high individual doses to the patient. Radiation protection of children is considered to be especially important, in view of the higher radiation risk factors for children. Health screening programmes, for example, for the early detection of breast cancer, involve a healthy population in which a small percentage of women have a malignant lesion which may be detected using mammography. Interventional radiology, cardiology and some nuclear medicine procedures result in high radiation doses to the patient. Clinical image quality criteria, referral guidelines and reference doses will be established for the latest digital detectors by building on previous work and a series of consensus meetings. In nuclear medicine, there is a debate on the administered activity for various nuclide procedures. This debate will be addressed via consensus meetings and surveys of national practice. The relationship between physical and clinical image quality indices will be addressed. This will assist in international standardization activities. Patient dose surveys and quality assurance tests will be undertaken on various high dose procedures. Similar work will be undertaken in mammography, bone mineral densitometry and paediatric radiology. Ethical issues in radiation protection will be assessed. Summary The intended benefits of the SENTINEL coordination action are: 1) Safer, more effective procedures and examinations using new technology in radiology 2) Greater public acceptance of the use of radiation in medicine 3) Safer, more cost-effective health care 4) Supporting the legislative agenda of the European Union 5) Contribution to the training of researchers. (author)