title: Flat-panel x-ray detector based on amorphous silicon versus asymmetric screen-film system: phantom study of dose reduction and depiction of simulated findings.
abstract: OBJECTIVE
  To compare a large-area amorphous silicon flat-panel detector with an asymmetric screen-film system for the depiction of simulated patterns of interstitial lung disease, nodules, and catheters, as well as for evaluation of dose reduction.
  
  
  METHODS
  Ground-glass, linear, miliary, and reticular patterns; nodules; and catheters were superimposed over an anthropomorphic chest phantom. Hard copies were generated at different dose levels (speeds: 400, 800, and 1,600) with a flat-panel detector and were compared with copies generated with an asymmetric screen-film system (speed, 400). Detection performance of eight radiologists was compared with a receiver operating characteristic analysis of 19,200 observations per pattern. A difference was significant with a P value of.05.
  
  
  RESULTS
  There was no statistically significant difference between the flat-panel detector and the asymmetric screen-film system at the same speed (P >.05) and between the flat-panel detector at a speed of 800 and the asymmetric screen-film system at a speed of 400 (P >.05). The visibility of linear, miliary, and reticular patterns over lucent lung and of nodules smaller than 10 mm and catheters over obscured chest regions on copies generated at a speed of 1,600 with the flat-panel detector decreased, compared with the visibility of these features on copies generated with the asymmetric screen-film system (P <.05).
  
  
  CONCLUSIONS
  The diagnostic performance of the flat-panel detector is comparable to that of the asymmetric screen-film system for depiction of all simulated patterns of interstitial lung diseases, nodules, and catheters at the same speed and offers the potential of dose reduction to a speed of 800.
authors.affiliation: Department of Clinical Radiology, University of Muenster, Albert-Schweitzer-Strasse 33, Germany. bernhart@uni-muenster.de
authors.forename: Ulrike
authors.initials: U
authors.lastname: Rapp-Bernhardt
authors.forename: Friedrich W
authors.initials: FW
authors.lastname: Roehl
authors.forename: Robert C
authors.initials: RC
authors.lastname: Gibbs
authors.forename: Hagen
authors.initials: H
authors.lastname: Schmidl
authors.forename: Ulrich W
authors.initials: UW
authors.lastname: Krause
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Bernhardt
mesh_terms: D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging*; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011859:Radiography; D012825:Silicon; D014963:X-Ray Intensifying Screens
chemical_list: D012825:Silicon