ESR News October 2014
The importance of quality assurance and dosimetry in Radiology
John Damilakis, Professor of Medical Physics
Medical imaging involves the integration of a great number of procedures, including reception and guidance of the patient, equipment selection and installation, periodic image quality and radiation exposure control, and examination interpretation and reporting. The clinical output provided by the imaging department depends on all these procedures, which must be carefully controlled. A quality assurance (QA) programme is needed to a) ensure adequate clinical performance and compliance with standards at low cost and b) maintain equipment performance with minimum radiation exposure.
Preparation of technical specifications of x-ray equipment is an important part of QA. Specifications should reflect the department’s clinical requirements. Users should define all technical features of equipment and clinical applications, safety requirements, installation, operation and maintenance requirements, items to accompany the equipment, training requirements, essential spare parts required as well as the schedule of supply. Other specific requirements related to the equipment, such as compatibility with existing archiving and communication networks, space available for the installation of the equipment, shielding for radiation protection, and maintenance costs, should be taken into consideration. All equipment must be accompanied by technical documents as well as documents of warranty.
It is the responsibility of the supplier, manufacturer or distributor, to ensure that the equipment conforms to the requirements of the technical specifications. It is the responsibility of the owner to ensure that the facilities available for the installation are properly shielded to provide adequate radiation protection according to the national legal requirements. Installation should be followed by procedures especially developed to ensure that the equipment operates according to the specifications described in the purchase contract and meets all radiation protection requirements. It is the responsibility of the owner and the supplier to provide adequate training to the staff on the proper operation of the equipment. All operators should be certified according to national standards. Maintenance personnel should be adequately trained in the regular maintenance and repair of equipment. According to the recently published European Commission Basic Safety Standards (BSS), member states shall ensure that medical physics experts take responsibility for dosimetry, including physical measurements for evaluation of the dose delivered to the patient and other individuals subject to medical exposure; give advice on medical radiological equipment and contribute to several processes related to QA, such as the preparation of technical specifications for medical radiological equipment and installation design, acceptance testing of radiological equipment, training of practitioners and other staff in relevant aspects of radiation protection; and take responsibility for the surveillance of the radiological installations and the optimization of the radiation protection of patients (1).
Proper use of the x-ray equipment requires well-trained staff and a programme for quality control (QC). A QA programme should consist of standardised periodic tests developed to ensure that all x-ray systems consistently meet specifications and are used in a way which provides radiation safety for patients and personnel. Radiation exposure levels must be measured to ensure that the examination is performed with the lowest possible dose to the patient without loss of diagnostic information. Several national and international professional and scientific societies and organisations have prepared QC recommendations and programmes for facilities with radiography, fluoroscopy, mammography, dual x-ray absorptiometry, dental radiography, computed tomography and fluoroscopically-guided interventional equipment. Users should take available information into consideration in order to develop their own QC programme according to local and national needs and requirements.
1. Council of the European Union. (2013). Council Directive 2013/59/Euratom laying down basic safety standards for protection against the dangers arising from exposure to ionising radiation, and repealing Directives 89/618/Euratom, 90/641/Euratom, 96/29/Euratom, 97/43/Euratom and 2003/122/Euratom. Official Journal L-13 of 17.01.2014.