X-Ray Filter Design and Its Evaluation in Dual-Energy X-Ray Absorptiometry (DXA)

This paper reports a new X-ray beam geometry to acquire two separated polychromatic X-rays as well as two separated fan beams using parallel different filters built in a single collimator. This newly designed X-ray spectrum was generated by a single X-ray shot but had the effect of double X-ray exposure. The two separated filters were used side by side. The first filter for the low energy spectra was 0.5 mm thick erbium and the second filter for the high energy spectra was composed of two layers of a 0.8 mm of copper and 0.4 mm of rhodium. This combination of filters showed excellent performance of X-ray beam hardening regardless of the bone thickness in the soft tissue under DXA conditions.