title: Monochromatic x-rays for low-dose digital mammography: preliminary results.
abstract: OBJECTIVE
  The feasibility of using monochromatic x-ray imaging generated from an x-ray tube and a multilayer reflector for digital mammography with a low radiation dose was examined.
  
  
  METHODS
  A multilayer mirror was designed to select the x-ray peak with an energy of 21.5 keV generated from an x-ray tube with a tungsten target and was fabricated by the ion-beam sputtering deposition system. Monochromatic x-ray images were obtained from an experimental digital mammography setup with a scanning stage. The performance of the system was evaluated using a breast phantom, a spectrometer, and a radiation dosimeter. We measured the contrast-to-noise ratio and performed the 10% modulation function test to determine image quality and resolution.
  
  
  RESULTS
  The monochromatic beam from the multilayer reflector had a full-width-at-half-maximum of 0.9 keV at 21.5 keV, and the reflectivity was 0.70, which was 90% of the designed value. The polychromatic and monochromatic x-rays showed radiation doses of 0.497 and 0.0415 mGy, respectively. The monochromatic x-ray image shows fibers, calcifications, and masses more clearly than the polychromatic x-ray images do. The image contrast of the monochromatic x-rays was 1.85 times higher than that of the polychromatic x-rays. The experimental mammography setup had a spatial resolution of 7 lp/mm with both x-rays.
  
  
  CONCLUSIONS
  Monochromatic x-rays generated using a multilayer mirror may be a useful diagnostic tool for breast examination by providing high contrast imaging with a low radiation dose.
authors.affiliation: Department of Radiology, Wonkwang University School of Medicine, Jeonbuk 570-749, Republic of Korea. khy1646@wonkwang.ac.kr
authors.forename: Kwon-Ha
authors.initials: KH
authors.lastname: Yoon
authors.forename: Young Man
authors.initials: YM
authors.lastname: Kwon
authors.forename: Byoung-Jung
authors.initials: BJ
authors.lastname: Choi
authors.forename: Hyun Hwa
authors.initials: HH
authors.lastname: Son
authors.forename: Cheol Woo
authors.initials: CW
authors.lastname: Ryu
authors.forename: Kwon Su
authors.initials: KS
authors.lastname: Chon
authors.forename: Seong Hoon
authors.initials: SH
authors.lastname: Park
authors.forename: Sun Kwan
authors.initials: SK
authors.lastname: Juhng
mesh_terms: D008327:Mammography / Q000379:methods*; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D014965:X-Rays