Improvement in image quality of computed radiography systems for mammography

The image quality of three experimental computed radiography (CR) mammography systems was compared through the measurement of commonly accepted image-quality metrics such as modulation transfer function (MTF) and detective quantum efficiency (DQE). The design and configuration of the scanners in the three systems were different in that they had different signal extraction strategies for each storage phosphor screen. Efforts were also made to improve the image quality through changes in phosphor layers, phosphor particle morphology, particle size distribution, and phosphor binder ratio. The effects on overall image quality as a result of these improvements were demonstrated on these systems. It was found that there were significant variations in system MTF and DQE, depending on how the CR system was configured. Higher system MTF does not always lead to higher DQE. Screen designs as well as scanning strategies need to be taken into consideration in order to achieve image quality improvements for the application of mammography.