ABSTRACT
To avoid the purchase of a digital mammography system by radiologists with intrinsic characteristics not able to fulfil the physical-technical quality requirements of the acceptance tests of the European guidance document, typetesting of digital equipment was introduced in the organisation and legislation of the Flemish breast cancer screening programme. Typetesting is performed for two types of instrumentation: systems for image capture and -processing and systems for image presentation. Typetesting is finalised or ongoing for eight DR systems and four CR systems. Eight workstations were or are submitted to the typetesting for image presentation. Experiences gained in typetesting of systems for image capture and -processing up to now show that the contrast-detail analysis of CDMAM phantom imaging and the homogeneity tests are most stringent. In general DR performs better than CR in imaging performance. Typetesting for image presentation has shown no difference in quality between CRT and LCD monitors. Furthermore, 3 MP monitors also pass the tests. However, to get the full resolution capabilities of the image capture system zooming in and scrolling over the image is necessary, which is time-consuming in clinical practice. Finally, we emphasize that typetesting involves also an evaluation of a set of clinical images by the working party of radiologists and that succeeding in typetesting does not mean that a particular system passes automatically the acceptance testing. A perfect tuning of the system and the coupling to a high quality X-ray system is necessary as well.
Subject(s)
Breast Neoplasms/diagnostic imaging , Image Processing, Computer-Assisted/standards , Mammography/standards , Mass Screening/standards , Belgium , Benchmarking/methods , Computer Systems/standards , Computer Terminals/standards , Data Display/standards , Europe , Female , Humans , Image Processing, Computer-Assisted/instrumentation , Liquid Crystals , Mammography/instrumentation , Phantoms, Imaging , Quality Assurance, Health Care/methods , Quality Control , Radiation Dosage , Radiographic Image Enhancement/standards , Tomography, X-Ray Computed/instrumentation , Tomography, X-Ray Computed/standardsABSTRACT
An evaluation of the image quality of an amorphous silicon flat-panel detector system and a computed radiology system compared with a screen-film system was performed by means of contrast-detail phantom images. Hard and soft copy images were evaluated. Although patient dose at clinical settings was strongly decreased with the amorphous silicon system, the low-contrast visibility with this system was still significantly better than with the screen-film system. For the computed radiology system, low-contrast visibility was comparable to the screen-film system. Best results were obtained by soft copy reading at full resolution with adaptation of contrast and brightness. Changing tube voltage (102-133 kV), or additional filtration, did not significantly affect image quality. However, low-contrast visibility improved significantly with increasing exposure. It was clearly demonstrated that, in chest imaging, the amorphous silicon system has superior imaging characteristics compared to the screen-film and the computed radiology system.
