title: A comparison of the response of storage phosphor and film radiography to small variations in X-ray exposure.
abstract: OBJECTIVE
  To determine the response to small repeated variations in X-ray exposure of storage phosphor (SP) plates compared with Ektaspeed Plus dental film.
  
  
  METHODS
  Exposure of SP plates and Ektaspeed Plus dental film was varied within a small range [8.62 microC kg-1 to 9.03 microC kg-1, (5%)]. Radiographs were digitized and SP plates read with a laser-based scanner. Nested analysis of variance, analysis of covariance, and regression analysis were used to test the relationship between exposure and the resulting signal.
  
  
  RESULTS
  The relationship between exposure and signal for digital images of film radiographs was not significant whereas the corresponding relationship for SP images was highly significant (P < 0.001, R2 = 0.44).
  
  
  CONCLUSIONS
  Over the narrow range of X-ray exposures studied there was a significant direct linear relationship between exposure and digital gray-scale values for SP images but not for digital images of Ektaspeed Plus films.
authors.affiliation: Mallinckrodt Institute of Radiology, Washington University, St Louis, MO 63110, USA.
authors.forename: C F
authors.initials: CF
authors.lastname: Hildebolt
authors.forename: G
authors.initials: G
authors.lastname: Fletcher
authors.forename: N
authors.initials: N
authors.lastname: Yokoyama-Crothers
authors.forename: G L
authors.initials: GL
authors.lastname: Conover
authors.forename: M W
authors.initials: MW
authors.lastname: Vannier
mesh_terms: D000704:Analysis of Variance; D007091:Image Processing, Computer-Assisted; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement; D011861:Radiography, Dental / Q000295:instrumentation / Q000379:methods; D019252:Radiography, Dental, Digital; D012044:Regression Analysis; D014962:X-Ray Film; D014963:X-Ray Intensifying Screens