title: Musculoskeletal imaging with a prototype photon-counting detector.
abstract: OBJECTIVE
  To test a digital imaging X-ray device based on the direct capture of X-ray photons with pixel detectors, which are coupled with photon-counting readout electronics.
  
  
  METHODS
  The chip consists of a matrix of 256 × 256 pixels with a pixel pitch of 55 μm. A monolithic image of 11.2 cm × 7 cm was obtained by the consecutive displacement approach. Images of embalmed anatomical specimens of eight human hands were obtained at four different dose levels (skin dose 2.4, 6, 12, 25 μGy) with the new detector, as well as with a flat-panel detector.
  
  
  RESULTS
  The overall rating scores for the evaluated anatomical regions ranged from 5.23 at the lowest dose level, 6.32 at approximately 6 μGy, 6.70 at 12 μGy, to 6.99 at the highest dose level with the photon-counting system. The corresponding rating scores for the flat-panel detector were 3.84, 5.39, 6.64, and 7.34. When images obtained at the same dose were compared, the new system outperformed the conventional DR system at the two lowest dose levels. At the higher dose levels, there were no significant differences between the two systems.
  
  
  CONCLUSIONS
  The photon-counting detector has great potential to obtain musculoskeletal images of excellent quality at very low dose levels.
authors.affiliation: Department of Radiology, Medical University of Vienna, Waehringer Guertel 18-20, AT-1090 Vienna, Austria. michael.gruber@meduniwien.ac.at
authors.forename: M
authors.initials: M
authors.lastname: Gruber
authors.forename: P
authors.initials: P
authors.lastname: Homolka
authors.forename: M
authors.initials: M
authors.lastname: Chmeissani
authors.forename: M
authors.initials: M
authors.lastname: Uffmann
authors.forename: M
authors.initials: M
authors.lastname: Pretterklieber
authors.forename: F
authors.initials: F
authors.lastname: Kainberger
mesh_terms: D002102:Cadaver; D004867:Equipment Design; D006225:Hand / Q000000981:diagnostic imaging*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000295:instrumentation* / Q000379:methods; D009140:Musculoskeletal Diseases / Q000000981:diagnostic imaging*; D017785:Photons; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement / Q000295:instrumentation* / Q000379:methods