%0 Journal Article
%T A Tunable Energy Filter for Medical X-Ray Imaging
%A Erik Fredenberg
%A Bj£¿rn Cederstr£¿m
%A Magnus £¿slund
%A Carolina Ribbing
%J X-Ray Optics and Instrumentation
%D 2008
%I 
%R 10.1155/2008/635024
%X A multiprism lens (MPL) is a refractive X-ray lens, and its chromatic properties can be employed in an energy filtering setup to obtain a narrow tunable X-ray spectrum. We present the first evaluation of such a filter for medical X-ray imaging. The experimental setup yields a 6.6 gain of flux at 20 ¡é ? ¡ëkeV, and we demonstrate tunability by altering the energy spectrum to center also around 17 and 23 ¡é ? ¡ëkeV. All measurements are found to agree well with ray-tracing and a proposed geometrical model. Compared to a model mammography system with absorption filtering, the experimental MPL filter reduces dose 13 ¡é ? ¡°25% for 3 ¡é ? ¡°7 ¡é ? ¡ëcm breasts if the spectrum is centered around the optimal energy. Additionally, the resolution is improved 2.5 times for a 5 ¡é ? ¡ëcm breast. The scan time is increased 3 times but can be reduced with a slightly decreased energy filtering and resolution.
%U http://dx.doi.org/10.1155/2008/635024