New Transfer Theory Relationships for Signal and Noise Analyses of X-Ray Detectors

• Main Author: Cunningham, Ian A
• Format: Report
• Language: English
• Subjects: ACCURACY; BREAST CANCER; DETECTORS; DIGITAL SYSTEMS; DQE(DETECTIVE QUANTUM EFFICIENCY); HIGH DENSITY; MAMMARY GLANDS; MAMMOGRAPHY; Medicine and Medical Research; OPTIMIZATION; Radiofrequency Wave Propagation; SIGNAL TO NOISE RATIO; X RAYS

X-ray mammography is the most reliable method available at present for the detection of breast cancer in screening programs. Unfortunately, it still misses many cancers, particularly in the radiographically dense breast more common in younger populations where the benefits of mammography screening are more controversial. Digital mammography holds the promise of improved specificity and sensitivity for the detection of small cancers. However, superior image quality can only be achieved if these digital systems are optimally designed to extract all information possible from the x-ray beam. The metric most generally accepted to describe signal and noise performance of detectors is the detective quantum efficiency (DQE), and theoretical methods for predicting the DQE are essential for the optimal design of new systems. Current methods using cascaded-systems analyses are simplistic and do not agree very well with measurements. In this research, we introduced the idea of parallel cascades as a means of developing comprehensive models of x-ray detectors that accurately describe the DQE of many x-ray systems. We discovered a mathematical description of the required cross- spectral noise-power density and showed that this approach gives an accurate estimate of the DQE based on design parameters. The results of this research are now used routines in the design and assessment of new x-ray systems by scientists and engineers in both academic and industrial laboratories around the world.