Acceptance testing of fluoroscopy systems used for interventional purposes

Acceptance testing and routine quality assurance (Q A) of X ray systems is a requirement of the European Medical Exposures Directive (97/43/EURATOM) and this requirement was implemented into Irish legislation in 2002. The legislation also states that special consideration should be given to the QA and dose assessment of high dose procedures such as interventional fluoroscopy. International and European guidance documents are available, containing testing methodologies and criteria against which equipment may be judged. These guidelines have been used to develop in-house QA protocols for testing fluoroscopy systems. Protocols are reviewed on a regular basis as part of the QA programme. New developments in diagnostic imaging technology are providing challenges for those involved in fluoroscopy QA. Flat-panel detector (FPD) digital fluoroscopy systems are beginning to replace Image Intensifier (II) technology in the interventional fluoroscopy room and are often marketed as a 'low dose' imaging modality. Mobile C-arm II/TV systems are becoming increasingly more complex, with numerous options and software settings which may have significant dose and image quality implications. The time required to perform comprehensive testing, analysis and reporting of all variables on complex fluoroscopy systems is a real challenge in a busy hospital environment. The aim of this study was to compare the results of acceptance testing for several different fluoroscopy configurations and highlight some recurring problems. Acceptance testing was carried out on sixteen fluoroscopy systems (interventional II/TV, interventional FPD, mobile C-arm II/TV) in a number of hospitals in Ireland from 1999 to present. Tests included assessment of tube and generator performance, radiation dose, image quality, electrical and mechanical safety, equipment design and radiation protection features. Tests were performed using a calibrated ionization chamber and kVp/exposure image quality test objects and other standard test tools. time meter, Leeds image quality test results and other standard test tools. The results for sixteen fluoroscopy systems will be presented. All systems were found to have failed one or more acceptance tests. Dose rate, image quality and radiation issues were identified on the majority of systems tested. Radiation dose and image quality results for a new vascular interventional FPD system will be presented. The results have been compared against two conventional vascular II/TV systems. Results show that patient entrance dose rate measurements are comparable on all three systems (approx. 4mGy/min). Image quality results are also comparable (noise, threshold contrast detail detectability and limiting spatial resolution); however, the limiting spatial resolution was slightly greater on the FPD system. For the FPD in digital acquisition mode, it was found that the dose per frame at the detector entrance was greater than that measured on the majority of fluoroscopy systems, and this was most likely due to the relatively high default clinical 'dose' setting. Results will also be presented for a number of modern mobile C-arm II/TV systems. The systems were found to have a wide variety of user-selectable fluoroscopy modes and filtration which had a noticeable impact on the measured dose and resultant image quality. options, many of Discussion. This study highlights the importance of comprehensive acceptance testing for complex fluoroscopy systems. It would be beneficial to liaise with the system applications' specialist and the clinical users prior to acceptance testing, to ascertain the user's requirements and clinical settings. This will assist with efficient testing of the relevant modes of operation. The default clinical 'dose' setting should be optimized to ensure that it is as low as reasonably achievable. Comparative studies of new systems will assist with the on-going development of testing guidelines and criteria of acceptability for modern fluoroscopy equipment