A wide fan-beam dual-energy X-ray absorptiometry for forearm

Abstract

Social population ageing has given rise to the number of people with osteoporosis. Compared with current dual energy X-ray absorptiometry (DEXA) for total body, spine or hip, the DEXA for the forearm used in regular physical exams is rare and relative expensive. We propose a new cost-effective fast wide fan-beam DEXA for forearm, offering reliable results that would be used in conjunction with the clinical risk factors as an aid to the physician in diagnosis of osteoporosis. Firstly, we utilize 28 degrees fan-beam whose width almost completely covers, even exceeds width of adults' forearm. This wide fan-beam make it possible to obtain one cross-sectional data via single exposure, rather than traditional zigzag scan or narrow angle scan. Hence, our new design improves measuring speed and makes forearm physical exams more effective than before. Secondly, instead of expensive CZT detectors or two sets of array detectors employed in conventional dual-energy equipment, our system proposed uses only one cost-effective set of array detectors capturing photons from two scans in one measurement. Multi-group experiments validate the efficiency of this new design which provides a better high-low energy spectrum with a clear separation between different energy and high intensity of photons at high energy. Moreover, piecewise method optimizes previous surface fitting algorithm by giving different fitting formulas in different thickness areas. All make contribution to offering accurate BMD (Bone Mineral Density, g/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) and BMC (Bone Mineral Content, g/cm) as well as clear progress on the quality and SNR of the high-energy image.