A prototype kinestatic charge detector (KCD) has been built at the University of Tennessee, Memphis, with a resolution of 0.2 by 0.2 mm and a field of view of 40 by 40 cm. This KCD prototype was designed specifically for chest radiography, and has produced clinical chest radiographs with lower patient dose and higher image quality than can be achieved with screen/film or photostimulable phosphor systems. In a previous publication the ability of the KCD prototype to acquire dual-energy x-ray images was demonstrated by scanning the same object twice, at two different kVp settings and with two different filters. The accuracy and repeatability of the KCD allowed separate bone and tissue images of a frozen turkey to be produced. For clinical dual-energy x-ray imaging, it would be desirable to acquire the two images of the patient at two different x-ray spectra in one scan, in order to prevent image artifacts due to patient motion. A dual-KCD imaging system for acquiring such images simultaneously is described in the patent literature. This paper describes one of the embodiments of such a dual-KCD dual-energy x-ray imager, which uses only one kVp, but two different filters. Images of a human chest phantom have been acquired using this single- kVp dual-filter technique using the KCD prototype, and are compared with dual-kVp dual- filter images, like those from Ref. 1, taken at the same skin dose.
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