A multiprism lens (MPL) is a refractive X-ray lens, and its chromatic properties can be employed in an energy filtering setup\r\nto obtain a narrow tunable X-ray spectrum. We present the first evaluation of such a filter for medical X-ray imaging. The\r\nexperimental setup yields a 6.6 gain of flux at 20 keV, and we demonstrate tunability by altering the energy spectrum to center also\r\naround 17 and 23 keV. All measurements are found to agree well with ray-tracing and a proposed geometrical model. Compared\r\nto a model mammography system with absorption filtering, the experimental MPL filter reduces dose 13ââ?¬â??25% for 3ââ?¬â??7 cm breasts\r\nif the spectrum is centered around the optimal energy. Additionally, the resolution is improved 2.5 times for a 5 cm breast. The\r\nscan time is increased 3 times but can be reduced with a slightly decreased energy filtering and resolution.
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