title: Optimizing image quality and dose for digital radiography of distal pediatric extremities using the contrast-to-noise ratio.
abstract: OBJECTIVE
  To investigate the influence of X-ray tube voltage and filtration on image quality in terms of contrast-to-noise ratio (CNR) and dose for digital radiography of distal pediatric extremities and to determine conditions that give the best balance of CNR and patient dose.
  
  
  METHODS
  In a phantom study simulating the absorption properties of distal extremities, the CNR and the related patient dose were determined as a function of tube voltage in the range 40 - 66 kV, both with and without additional filtration of 0.1 mm Cu/1 mm Al. The measured CNR was used as an indicator of image quality, while the mean absorbed dose (MAD) - determined by a combination of measurement and simulation - was used as an indicator of the patient dose.
  
  
  RESULTS
  The most favorable relation of CNR and dose was found for the lowest tube voltage investigated (40 kV) without additional filtration. Compared to a situation with 50 kV or 60 kV, the mean absorbed dose could be lowered by 24 % and 50 %, respectively, while keeping the image quality (CNR) at the same level.
  
  
  CONCLUSIONS
  For digital radiography of distal pediatric extremities, further CNR and dose optimization appears to be possible using lower tube voltages. Further clinical investigation of the suggested parameters is necessary.
authors.affiliation: University of Applied Science, Hamburg, Germany. robert.hess@haw-hamburg.de
authors.forename: R
authors.initials: R
authors.lastname: Hess
authors.forename: U
authors.initials: U
authors.lastname: Neitzel
mesh_terms: D002675:Child, Preschool; D005121:Extremities / Q000000981:diagnostic imaging*; D006801:Humans; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011835:Radiation Protection / Q000379:methods*; D011856:Radiographic Image Enhancement / Q000295:instrumentation / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D059629:Signal-To-Noise Ratio