Effect of flare on computed radiography systems

摘要

Cassette based computed radiography systems have continued to evolve in parallel with integrated, instant readout digital radiography DR systems. The image quality of present day computed radiography systems is approaching its theoretical limits but is still significantly inferior to DR. Our overall aim is to identify the fundamental limitations in computed radiography performance. This will provide a basis for the development of new approaches to improve photostimulable phosphor based computed radiography systems based either on cassettes or integrated systems. In this fundamental work flare has been evaluated by use of the disk transfer function. It is found that there is a significant, previously unnoticed low frequency drop in the modulation transfer function. However, it is not yet fully resolved if the measured flare is due solely to scattering of light in the readout system or whether scattered x-rays in the imaging plate cassette enhance it. Further work is necessary to resolve this issue. The likely effect of flare on proposed new computed radiography methods is also explored.