Photoelectronic Imaging for Radiology

This paper describes efforts to replace screen-film applications in radiology by an assemblage of x-ray intensifiers, video cameras, displays, and nonfilm storage media, the stimulus for which is twofold: economic and/or improved diagnostic performance. It is quite surprising to find that considerable financial benefit can occur by replacing film with a host of photoelectronic and electronic devices. This is due largely to the cost of a sheet of film being associated with each exposure, whereas photoelectronic devices provide one or thousands of exposures at essentially the same cost. It is not surprising to find, however, that the video output from a photoelectronic system can be readily digitized and made available for the benefits of image processing. This leads to rapid and convenient image acquisition and processing. The radiologist then has the benefit of an interactive display and can diagnose in a manner similar to that managed with the CT scanner. Heretofore, practice required reading out the film-based radiograph with a microdensitometer, followed by digitizing, processing, and producing processed radiographs. This technique is expensive and cumbersome. It was unable to stimulate the radiologist into being a routine user of processed radiographs. This paper examines the x-ray photon diagnostic image for its pertinent characteristics. It follows a review of current image acquisition components, i.e., screens, intensifiers, video tubes, and coupling optics. The purpose is to demonstrate an ability to acquire and transmit diagnostic x-ray images without significant degradation.