title: Influence of an object's z-axis location and location on the axial plane on the voxel value representation and uniformity in cone beam computed tomography.
abstract: OBJECTIVE
  This study aimed to determine the influence of an object's z-axis location and location on the axial plane on the voxel values in cone beam computed tomography.
  
  
  METHODS
  The CTP401 and CTP486 of the Catphan 500 phantom were scanned with an Alphard-3030 at 6 locations in the z-axis.
  
  
  RESULTS
  In CTP401, the voxel values of 3 inserts showed the lowest values when the center of the radiation field corresponded to under 2 or 4 cm of the z-axis center of CTP401. In CTP486, the voxel values showed the lowest values when the center of the radiation field corresponded to under 2 or 4 cm of the z-axis center of CTP486. On the same axial plane, the voxel values at the center showed significantly lower values than the off-center locations (P = .002).
  
  
  CONCLUSIONS
  The voxel values in the Alphard-3030 changed based on the z-axis location of the radiation field and were nonuniform on the same axial plane.
authors.affiliation: Department of Oral and Maxillofacial Radiology, Osaka University Graduate School of Dentistry, Osaka, Japan.
authors.forename: Kanako
authors.initials: K
authors.lastname: Nishino
authors.affiliation: Department of Oral and Maxillofacial Radiology, Osaka University Graduate School of Dentistry, Osaka, Japan. Electronic address: h-shima@dent.osaka-u.ac.jp.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Shimamoto
authors.affiliation: Department of Oral and Maxillofacial Radiology, Osaka University Graduate School of Dentistry, Osaka, Japan.
authors.forename: Naoya
authors.initials: N
authors.lastname: Kakimoto
authors.affiliation: Department of Oral and Maxillofacial Radiology, Osaka University Graduate School of Dentistry, Osaka, Japan.
authors.forename: Tomomi
authors.initials: T
authors.lastname: Tsujimoto
authors.affiliation: Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Mahidol University, Bangkok, Thailand.
authors.forename: Jira
authors.initials: J
authors.lastname: Chindasombatjaroen
authors.affiliation: Department of Oral and Maxillofacial Radiology, Osaka University Graduate School of Dentistry, Osaka, Japan.
authors.forename: Shumei
authors.initials: S
authors.lastname: Murakami
authors.affiliation: Department of Oral and Maxillofacial Radiology, Osaka University Graduate School of Dentistry, Osaka, Japan.
authors.forename: Souhei
authors.initials: S
authors.lastname: Furukawa
mesh_terms: D000465:Algorithms; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D006801:Humans; D056888:Patient Positioning; D019047:Phantoms, Imaging; D011857:Radiographic Image Interpretation, Computer-Assisted