Two fields, dual-energy x-ray absorptiometry and digital radiography, have advanced rapidly in their diagnostic capabilities in the past decade due to improvement in image processing and semiconductor detectors. While fan-beam absorptiometers (FBAs), as from Hologic and Lunar, can image an entire skeleton or any sub-area and provide quantitative bone density measures, body composition, and geometric dimensions, they cannot produce diagnostically useful, radiographic quality images. A high resolution, quasi-linear doctor would augment existing FBAs by adding radiographic quality imaging to their present capabilities, an otherwise unavailable combination. The proposed detector would have a 100 microM FWHM patient resolution, unity DQE, scan rates to 10 cm/sec, and 16 bit dynamic range. Comprised of a novel scintillator structure coupled to a specially designed CCD, it could be produced in arbitrary lengths with a variety of scintillator materials. Phase I will show feasibility by producing small CsI detector structures and comparing measurements to Monte Carlo models. Spatial performance should be limited only by interpixel Compton and elastic scattering. This will support Phase II improved fabrication methods, alternate scintillator material investigations, optimized CCD development, and building a prototype detector compatible with an existing FBA.
Potential applications exist wherever x-ray radiographs are required. Hologic, Inc. is specifically interested in using this detector to enhance their existing fan-beam bone densitometer line. Other medical examples include general radiography, digital subtraction angiography, and computer topography, including micro-computed tomography. There would also be a wide variety of non-medical imaging applications.
