Da Zhang

Toward a More Clarified Detective Quantum Efficiency Methodology: a Study of the Dqe Theory and Applications Da Zhang

Detective quantum efficiency (DQE) is widely accepted as the golden rule to objectively evaluate the performance of x-ray imaging systems. It provides a comprehensive characterization of an x-ray imaging system, because it combines several important image-quality-related measurements such as contrast, resolution, and noise, and because it measures the efficiency of the utilization of x-ray in the imaging process. Despite its importance, the current DQE methodology is imperfect in general agreement. The focus of this dissertation is to investigate the DQE methodology for digital x-ray imaging systems, in an effort to clarify some confusing aspects of the current DQE methodology. Through a detailed theoretical derivation of the DQE methodology for digital x-ray imaging, a more clarified understanding of the DQE theory is provided. Besides the re-visited DQE theory, techniques to determine the constituent parts of DQE, including the photon fluence, Modulation Transfer Function (MTF), and Noise Power Spectrum (NPS) are also discussed in this dissertation.