title: Optimization of chest films of equalization radiography (advanced multiple beam equalization radiography). Comparison by means of a receiver operating characteristic study of simulated nodular interstitial disease.
abstract: OBJECTIVE
  To optimize screen-film combinations for equalization radiography (advanced multiple beam equalization radiography [AMBER]), five different film-screen-technique combinations were compared by receiver operating characteristics study of simulated interstitial disease.
  
  
  METHODS
  The Ortho C-Lanex Regular and the Insight Thoracic Imaging HC system were compared in conventional nonequalized technique; T-Mat G-Lanex Regular and T-Max L-Lanex Regular were compared in conventional, nonequalized, and AMBER technique; and an experimental high-contrast, low-noise, near-zero crossover film-screen combination was compared in AMBER technique. Interstitial disease was simulated by superimposing birdseed on the back of a humanoid phantom. Twenty-five posterior-anterior radiographs were made with each technique. Seven observers scored the presence of interstitial disease in each of the quadrants on a 5-point scale following receiver operating characteristic methodology.
  
  
  RESULTS
  The highest performance was found with the experimental film-screen-AMBER combination (Az = 0.92) and the lowest with the T-Mat L-Lanex Regular-AMBER combination (Az = 0.83) and the Insight Thoracic Imaging HC system-conventional combination (Az = 0.85). T-Mat L-Lanex Regular-conventional ranked second (Az = 0.90) while T-Mat G-Lanex Regular-conventional (Az = 0.89), T-Mat L-Lanex Regular-AMBER (Az = 0.88) and Ortho-C-Lanex Regular-conventional (Az = 0.87) scored lower.
  
  
  CONCLUSIONS
  Higher contrast films in AMBER improve diagnostic performance, whereas a loss of information is found if the AMBER system is combined with lower contrast films.
authors.affiliation: Department of Diagnostic Radiology, University Hospital Leiden, Leiden, The Netherlands.
authors.forename: L J
authors.initials: LJ
authors.lastname: Schultz Kool
authors.forename: M
authors.initials: M
authors.lastname: van Proosdij
authors.forename: R
authors.initials: R
authors.lastname: van Metter
authors.forename: H A
authors.initials: HA
authors.lastname: Vrooman
authors.forename: N J
authors.initials: NJ
authors.lastname: Aarts
authors.forename: P M
authors.initials: PM
authors.lastname: Shaw
authors.forename: W R
authors.initials: WR
authors.lastname: Obermann
authors.forename: R J
authors.initials: RJ
authors.lastname: Heijboer
authors.forename: D S
authors.initials: DS
authors.lastname: Memel
authors.forename: J W
authors.initials: JW
authors.lastname: Oestmann
mesh_terms: D006801:Humans; D017563:Lung Diseases, Interstitial / Q000000981:diagnostic imaging*; D008961:Models, Structural; D012372:ROC Curve; D013902:Radiography, Thoracic / Q000379:methods*; D014963:X-Ray Intensifying Screens