title: Reduction of scatter-induced image noise in cone beam computed tomography: effect of field of view size and position.
abstract: OBJECTIVE
  To measure the effect of field of view (FOV) size and position on scatter-induced image noise in cone beam computed tomography (CBCT).
  
  
  METHODS
  A polymethyl methacrylate (PMMA) phantom containing air and aluminum underwent CBCT scanning, using seven FOVs ranging between 4 × 4 cm and 14 × 10 cm, positioned both centrally and according to a dental scan. Signal difference to noise ratio (SDNR) was measured on two-dimensional (2-D) projection images.
  
  
  RESULTS
  At a central position, SDNR decreased with increasing FOV size, ranging between 9.8 (14 × 10 cm) and 10.9 (4 × 4 cm). For dental FOV positions, SDNR values were between 6.3 (14 × 10 cm) and 9.5 (4 × 4 cm). To reach a constant SDNR, a dose reduction up to 76% was possible for small FOVs compared with the 14 × 10 cm FOV.
  
  
  CONCLUSIONS
  The use of small FOVs and peripheral FOV positioning decreases scatter at the detector, resulting in a considerable potential for reduction of radiation dose to the patient.
authors.affiliation: Lecturer, Department of Radiology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand; OMFS-IMPATH Research Group, Department of Imaging and Pathology, Faculty of Medicine, University of Leuven and Department of Oral and Maxillofacial Surgery, University Hospitals Leuven, Leuven, Belgium. Electronic address: pauwelsruben@hotmail.com.
authors.forename: Ruben
authors.initials: R
authors.lastname: Pauwels
authors.affiliation: Professor, OMFS-IMPATH Research Group, Department of Imaging and Pathology, Faculty of Medicine, University of Leuven and Department of Oral and Maxillofacial Surgery, University Hospitals Leuven, Leuven, Belgium.
authors.forename: Reinhilde
authors.initials: R
authors.lastname: Jacobs
authors.affiliation: Professor, Laboratory of Experimental Radiotherapy, Department of Oncology, Biomedical Sciences Group, University of Leuven, Leuven, Belgium.
authors.forename: Ria
authors.initials: R
authors.lastname: Bogaerts
authors.affiliation: Professor, Medical Physics & Quality Assessment, Department of Imaging and Pathology, Biomedical Sciences Group, University of Leuven, Leuven, Belgium.
authors.forename: Hilde
authors.initials: H
authors.lastname: Bosmans
authors.affiliation: Professor and Head, Department of Radiology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Soontra
authors.initials: S
authors.lastname: Panmekiate
mesh_terms: D054893:Cone-Beam Computed Tomography / Q000379:methods*; D019047:Phantoms, Imaging; D019904:Polymethyl Methacrylate; D012542:Scattering, Radiation; D059629:Signal-To-Noise Ratio
chemical_list: D019904:Polymethyl Methacrylate