Detector optimization for equalized dual-energy chest radiography

The authors are investigating the application of x-ray beam equalizers to dual-energy digital chest radiography. The beam equalizers force more x-ray flux through the dense patient regions and thereby result in an improved signal-to-noise ratio (S/N) in the mediastinum. The authors' present paper is optimizing the specialized dual-energy detector and equalizer response for improved mediastinal S/N while maintaining good lung S/N. The authors used a Philips computed radiography photostimulable phosphor detector, an AMBER (Oldelft) beam equalizer, and a Pixar/Sun image computer arrangement. A variable compensation (VC) technique we previously developed was used to eliminate shading artifacts in the equalized dual-energy images. We used a computer spectral simulation program to optimize beam filtration and kVp for maximum S/N with the equalization and VC techniques. A correlated noise reduction technique was further used to improve S/N