title: Assessment of the effective dose in supine, prone, and oblique positions in the maxillofacial region using a novel combined extremity and maxillofacial cone beam computed tomography scanner.
abstract: OBJECTIVE
  The objectives of this study were to assess the organ and effective doses (International Commission on Radiological Protection [ICRP] 103 standard) resulting from supine, prone, and oblique phantom positions in the maxillofacial region using a novel cone beam computed tomography (CBCT) device and to compare the results with conventional dental CBCT and multislice computed tomography (MSCT) devices.
  
  
  METHODS
  Measurements were performed using an anthropomorphic RANDO head phantom (Radiation Analogue Dosimetry System) with 20 MOSFET (metal-oxide-semiconductor field-effect transistor) dosimeters placed in the most radiosensitive maxillofacial organs. Effective doses were measured in 3 phantom positions using a combined extremity and maxillofacial CBCT device: the Planmed Verity CBCT scanner. Reference values were measured in the upright position with 2 CBCT devices and in the prone position with one MSCT scanner.
  
  
  RESULTS
  The Planmed Verity CBCT scanner effective doses were 247 μSv in supine, 192 μSv in prone, and 134 μSv in oblique position. The effective dose with ProMax 3D MAX CBCT was 168 μSv; with i-CAT Next Generation, 170 μSv; and with Philips Brilliance 64 MSCT, 781 μSv.
  
  
  CONCLUSIONS
  Head positioning has an important effect on the organ and effective doses. The Planmed Verity CBCT scanner effective dose results were comparable with those attained on 2 conventional CBCT devices and were considerably lower than the MSCT scanner results.
authors.affiliation: Department of Physics, University of Helsinki, Helsinki, Finland. Electronic address: juha.koivisto@planmeca.com.
authors.forename: J
authors.initials: J
authors.lastname: Koivisto
authors.affiliation: Department of Oral and Maxillofacial Surgery/Oral Pathology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Wolff
authors.affiliation: Department of Radiology, Medical Imaging Center, Tampere University Hospital, Tampere, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Järnstedt
authors.affiliation: Department of Radiology, Medical Imaging Center, Tampere University Hospital, Tampere, Finland; University of Tampere Medical School, Tampere, Finland.
authors.forename: P
authors.initials: P
authors.lastname: Dastidar
authors.affiliation: HUS Medical Imaging Center, University of Helsinki, Helsinki, Finland.
authors.forename: M
authors.initials: M
authors.lastname: Kortesniemi
mesh_terms: D054893:Cone-Beam Computed Tomography / Q000295:instrumentation*; D006257:Head / Q000000981:diagnostic imaging*; D006801:Humans; D056888:Patient Positioning; D019047:Phantoms, Imaging; D016684:Prone Position; D011829:Radiation Dosage; D011874:Radiometry / Q000295:instrumentation; D016683:Supine Position