title: Density conversion factor determined using a cone-beam computed tomography unit NewTom QR-DVT 9000.
abstract: OBJECTIVE
  The purpose of this study was to determine a conversion coefficient for Hounsfield Units (HU) to material density (g cm(-3)) obtained from cone-beam computed tomography (CBCT-NewTom QR-DVT 9000) data.
  
  
  METHODS
  Six cylindrical models of materials with different densities were made and scanned using the NewTom QR-DVT 9000 Volume Scanner. The raw data were converted into DICOM format and analysed using Merge eFilm and AMIRA to determine the HU of different areas of the models.
  
  
  RESULTS
  There was no significant difference (P = 0.846) between the HU given by each piece of software. A linear regression was performed using the density, rho (g cm(-3)), as the dependent variable in terms of the HU (H). The regression equation obtained was rho = 0.002H-0.381 with an R2 value of 0.986. The standard error of the estimation is 27.104 HU in the case of the Hounsfield Units and 0.064 g cm(-3) in the case of density.
  
  
  CONCLUSIONS
  CBCT provides an effective option for determination of material density expressed as Hounsfield Units.
authors.affiliation: Faculty of Medicine and Dentistry, Dentistry/Pharmacy Centre, University of Alberta, Edmonton, Alberta, Canada T6G 2N8. mlagravere@ualberta.ca
authors.forename: M O
authors.initials: MO
authors.lastname: Lagravère
authors.forename: Y
authors.initials: Y
authors.lastname: Fang
authors.forename: J
authors.initials: J
authors.lastname: Carey
authors.forename: R W
authors.initials: RW
authors.lastname: Toogood
authors.forename: G V
authors.initials: GV
authors.lastname: Packota
authors.forename: P W
authors.initials: PW
authors.lastname: Major
mesh_terms: D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D019047:Phantoms, Imaging; D011856:Radiographic Image Enhancement / Q000379:methods*; D012984:Software; D015898:Tomography Scanners, X-Ray Computed; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods*