title: Estimation of contrast of refraction contrast imaging compared with absorption imaging-basic approach.
abstract: OBJECTIVE
  We discuss the usefulness of the refraction contrast method using highly parallel X-rays as a new approach to minute lung cancer detection. The advantages of refraction contrast images are discussed in terms of contrast, and a comparison is made with absorption images.
  
  
  METHODS
  We simulated refraction contrast imaging using globules with the density of water in air as models for minute lung cancer detection. The contrast intensified by bright and dark lines was compared on a globule with the contrast of absorption images. We adopted the Monte Carlo simulation to determine the strength of the profile curve of the photon counts at the detector.
  
  
  RESULTS
  The obtained contrasts were more intense by two to three digits than those obtainable with the absorption contrast imaging method.
  
  
  CONCLUSIONS
  The contrast in refraction contrast imaging was more intense than that obtainable with absorption contrast imaging. A two to three digit improvement in contrast means that it is possible to greatly reduce the exposure dose necessary for imaging. Therefore, it is expected to become possible to detect the interfaces of soft tissues, which are difficult to capture with conventional absorption imaging, at low dosages and high resolution.
authors.affiliation: Department of Electrical Engineering and Information Science, Niihama National College of Technology, Ehime, Japan.
authors.forename: Masatsugu
authors.initials: M
authors.lastname: Hirano
authors.forename: Katsuhito
authors.initials: K
authors.lastname: Yamasaki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Okada
authors.forename: Sohei
authors.initials: S
authors.lastname: Kitazawa
authors.forename: Riko
authors.initials: R
authors.lastname: Kitazawa
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Ohno
authors.forename: Takashi
authors.initials: T
authors.lastname: Sakurai
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kondoh
authors.forename: Chiho
authors.initials: C
authors.lastname: Ohbayashi
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Katafuchi
authors.forename: Sakan
authors.initials: S
authors.lastname: Maeda
authors.forename: Kazuro
authors.initials: K
authors.lastname: Sugimura
authors.forename: Shinichi
authors.initials: S
authors.lastname: Tamura
mesh_terms: D000042:Absorption; D016477:Artifacts; D003198:Computer Simulation; D003287:Contrast Media; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging; D009010:Monte Carlo Method; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement / Q000379:methods*; D012031:Refractometry; D017356:Synchrotrons; D014965:X-Rays
chemical_list: D003287:Contrast Media