title: An objective comparison of four digital intra-oral radiographic systems: sensitometric properties and resolution.
abstract: OBJECTIVE
  To compare the sensitometric properties and resolution of four digital intra-oral radiographic systems.
  
  
  METHODS
  Three CCD-based systems were evaluated, RVG-4 (Trophy Radiologic, Paris, France) CDR (Schick Technologies Inc, Long Island, NY, USA) and Dixel (Morita, Kyoto, Japan) and a photostimulable phosphor system (Digora, Soredex-Orion, Helsinki, Finland). The sensitometric properties were determined by measuring the gray levels at increasing exposures without making any gray-scale adjustments. MTF was measured using images of a 10 microns width slit inclined to the long and short axes of the detectors.
  
  
  RESULTS
  The CCD-based systems showed a linear relationship between exposure and gray level although there were some differences in sensitivity. In RVG-4, the gray level saturated at a lower exposure. Digora showed a logarithmic relationship at uniform exposure. However, there was a linear relationship when it was exposed below the calibration dose. The MTF was highest with RVG-4 and the lowest with the Digora.
  
  
  CONCLUSIONS
  Each system has its own specific properties; RVG-4 has the highest resolution with the narrowest latitude, whereas Digora has the wider latitude but the lowest resolution.
authors.affiliation: Department of Oral Radiology, Showa University School of Dentistry, Kitasenzoku 2-1-1, Ohta-ku, Tokyo, 145-8515, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Araki
authors.forename: A
authors.initials: A
authors.lastname: Endo
authors.forename: T
authors.initials: T
authors.lastname: Okano
mesh_terms: D015502:Absorptiometry, Photon; D004867:Equipment Design; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation / Q000379:methods; D016014:Linear Models; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement / Q000295:instrumentation / Q000379:methods*; D019252:Radiography, Dental, Digital / Q000295:instrumentation / Q000379:methods*