The long-term goals of this digital radiography project is the reduction of patient dose and production of images that demonstrate increased perspicuity for neoplasms and other lesions in comparison with available techniques. Currently, there are no modalities known to us that take advantage of the broad bremmstrahlung spectrum emitted by the typical x-ray unit and it's potential for tissue differentiation and contrast enhancement. A commercially available GE unit creates dual-energy photon sets by double exposing the patient, each exposure accomplished at a different kVp. Ion Optics will develop a modern radiation detector to record the energy of each photon. The required segregation into two or more data sets, labeled by energy, can then be accomplished by software. This algorithm would be adjustable, as per the characteristics of each patient, in a process akin to windowing. This approach requires only a single exposure, reducing motion artifacts to a minimum and is likely to lead to reduced patient exposure. Required instrumentation for acquiring data from many parallel channels has been developed for fast radiation detectors in nuclear physics. Phase I of this project will concentrate on proving the efficacy of high-pressure gas micro-pattern detectors. Such detectors are known to have good object and energy resolution with excellent linearity and SNR. The problem of parallax presented by having a thick gas absorber has been largely solved.
