| Active matrix flat-panel imagers (AMFPIs) are large-area, digital x-ray imaging systems incorporating a thin-film-based flat-panel array. While such flat-panel imagers offer numerous advantages over other existing radiographic and fluoroscopic devices, it is important to quantify performance of these imagers objectively since such a performance assessment can aid to identify problems or weaknesses in the present technology thereby furthering the goal of achieving maximum theoretical performance. As an extension of our group's general approach to develop optimized designs, system performance of existing and hypothetical AMFPIs was evaluated theoretically and empirically for the applications of radiotherapy imaging, fluoroscopy, and mammography. This performance assessment was based on performance metrics such as x-ray sensitivity, spatial resolution (i.e., MTF), noise characteristics (i.e., NPS), and the transfer efficiency of signal-to-noise information (i.e., DQE). Theoretical investigation was performed based on a linear systems model using a mathematical formalism called cascaded systems formalism. Furthermore, the theoretical model was used to examine the performance of existing imager designs as well as hypothetical designs incorporating a variety of strategies to overcome factors limiting the performance of the present AMPFI technology. |
