title: 3D automatic exposure control for 64-detector row CT: radiation dose reduction in chest phantom study.
abstract: OBJECTIVE
  The purpose of this study was to determine the utility of three-dimensional (3D) automatic exposure control (AEC) for low-dose CT examination in a chest phantom study.
  
  
  METHODS
  A chest CT phantom including simulated focal ground-glass opacities (GGOs) and nodules was scanned with a 64-detector row CT with and without AEC. Performance of 3D AEC included changing targeted standard deviations (SDs) of image noise from scout view. To determine the appropriate targeted SD number for identification, the capability of overall identification with the CT protocol adapted to each of the targeted SDs was compared with that obtained with CT without AEC by means of receiver operating characteristic analysis.
  
  
  RESULTS
  When targeted SD values equal to or higher than 250 were used, areas under the curve (Azs) of nodule identification with CT protocol using AEC were significantly smaller than that for CT protocol without AEC (p < 0.05). When targeted SD numbers at equal to or more than 180 were adapted, Azs of CT protocol with AEC had significantly smaller than that without AEC (p < 0.05).
  
  
  CONCLUSIONS
  This phantom study shows 3D AEC is useful for low-dose lung CT examination, and can reduce the radiation dose while maintaining good identification capability and good image quality.
authors.affiliation: Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan. palm_kei@yahoo.co.jp
authors.forename: Keiko
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Ohno
authors.forename: Hisanobu
authors.initials: H
authors.lastname: Koyama
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kono
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Inokawa
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Onishi
authors.forename: Munenobu
authors.initials: M
authors.lastname: Nogami
authors.forename: Daisuke
authors.initials: D
authors.lastname: Takenaka
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Araki
authors.forename: Kazuro
authors.initials: K
authors.lastname: Sugimura
mesh_terms: D000465:Algorithms; D001822:Body Burden; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008168:Lung / Q000000981:diagnostic imaging*; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011835:Radiation Protection / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods*