MODIFIED POLYENERGETIC X-RAY SPECTRA FOR DUAL ENERGY METHOD.

The aim of the present study was the optimization of polyenergetic x-ray spectra for Dual energy imaging. The latter was accomplished by using various combinations of filter thicknesses and kVp. X-ray spectra were optimized by using double track x-ray tubes equipped with Molybdenum (Mo) and Rhodium (Rh), Mo and Tungsten (W), Rh and W, and a W or Rh anode combined with various K-edge filters and combinations. Filtering of energy spectra was implemented by determining the optimum combination and thicknesses of the lanthanides filters. The filtered spectra were normalized at standard exposure conditions. Best performance characteristics were obtained from the combination of Rh anode spectrum at 25kVp filtered with 100 μm Rh for low energy, and W anode spectrum at 50Vp filtered with 400 μm Ce for mammography, with mean energy values 19.57 and 30.10KeV respectively. For bone densitometry, best results were obtained from a W anode filtered spectrum at 110KVp with 900 μm Ce and mean energy values 37.78 and 85.56KeV for low and high energy respectively. [ABSTRACT FROM AUTHOR]