The conventional x-ray source for mammography, with a molybdenum (Mo) anode and Mo filter, works well for breasts of low to moderate x-ray attenuation, but is not readily adaptable to the production of higher x-ray energies that are more suitable for imaging breasts of higher attenuation. Accordingly, alternative sources with anodes of rhodium (Rh) and tungsten (W) have been developed to improve the efficiency of the examination for thick or radiographically dense breasts. We have applied previously developed multiparameter optimization techniques to imaging systems using these alternative x-ray sources. Since these sources are intended to improve mammography of high-attenuation breasts, optimizations were performed for a range of breast thicknesses. Since high attenuation is generally associated with high scatter, optimizations for each source were done with a high-ratio, air-interspace grid similar to the one developed in our previous work. Preliminary results have been obtained for optimized system configurations using a W-anode source with Mo, Rh, and aluminum (Al) filters, and for a Mo-anode source with Rh filtration. These results indicate that the alternative sources studied can significantly improve the efficiency of mammography of high-attenuation breasts.
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