Comparison of a-Si:H CsI flat-panel digital imaging systems with a CCD based system, CR systems, and conventional screen-film systems - A contrast-detail phantom study

Low-contrast detail detectability was evaluated and compared for a flat-panel digital chest system, a computed radiography (CR) system and a conventional screen/film (SF) system. Images of a contrast-detail phantom were acquired using these three systems under identical conditions. Additional images were acquired at varied exposures to study the potential for reduction of patient exposure using the flat-panel system. The results demonstrated that in chest imaging, the flat-panel system performed significantly better than the CR and the SF systems while the latter two performed about the same. Alternatively, an exposure reduction of at least 50% is possible if the same performance is maintained. For mammographic imaging, detectability for microcalcifications (μCs) was evaluated and compared for a flat-panel based full-field digital mammography (FFDM) system, a charge-coupled device (CCD)-based small-field system, a high resolution CR system and a conventional SF system. Images of simulated calcifications of three size ranges were acquired and evaluated by readers for detectability of the μCs. A Receiver Operating Characteristics (ROC) analysis was also performed to compare the overall detection accuracy of these four mammographic imaging systems. Our results show that in both the detectability analysis and the ROC analysis, the flat-panel systems performed the best followed by the screen/film system. The CCD based system showed better detection accuracy compared to the CR system in the ROC analysis. However, there was no significant difference between the CCD and the CR systems in the detectability analysis.