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27 June 1988 Rejection Of Scattered Radiation And Veiling Glare In A Large-Field Image-Intensifier System
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A prototype system for digital fluorography of the chest is under development in our research laboratory. It consists of a special-procedures x-ray unit upgraded with a 40-cm image intensifier, a Compumotor driven multiple-slit assembly, and MicroVAX II based frame grabber and frame processor. Contrast in an image-intensifier x-ray system is degraded by scattered radiation and veiling glare. They both increase with the diameter of the image-intensifier input phosphor. Grids, air gaps, and paired scanning apertures are not effective against veiling glare. In our prototype system both scattered radiation and veiling glare are rejected using the electronic-collimation principle. A multiple-slit assembly is scanned between the x-ray tube and the patient. Images are recorded and digitized for each position of the slit assembly. The resultant image is reconstructed from a series of digitized slit images using an appropriate computer algorithm. Technologies for manufacturing the multiple-slit assembly and the image-reconstruction algorithms are discussed. The peak-detection algorithm does not require as accurate stepping of the slit assembly as the threshold-and-summation algorithm, but it wastes a portion of the radiation dose. Comparative single- and dual-energy images of a chest phantom are presented. Superior separation of bone and soft-tissue images was achieved when the electronic scanning slit was used because, of more efficient scatter rejection.
© (1988) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Dinko Plenkovich and Chiraprakash Nayak "Rejection Of Scattered Radiation And Veiling Glare In A Large-Field Image-Intensifier System", Proc. SPIE 0914, Medical Imaging II, (27 June 1988);

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