title: Application of subsecond rotation scan to helical CT for lung cancer screening.
abstract: OBJECTIVE
  To clarify whether the benefit of a reduced effective scan width obtained using a smaller pitch outweighs the disadvantage of increased noise in the application of a subsecond helical CT to mass screenings for lung cancer.
  
  
  METHODS
  Twenty-two helical CT scans of the lung were obtained in 11 healthy subjects using the following parameters: 1) scan 1 was performed at 120 kVp, 50 mA, 10-mm collimation, 1-second/rotation, helical pitch of 2.0; and 2) scan 2 was performed at 120 kVp, 50 mA, 10-mm collimation, 0.75-second/rotation, helical pitch of 1.5. Computer-generated nodules measuring 10 mm and 6 mm in diameter showing ground-glass opacity were superimposed on these images. The detectability of each nodule was evaluated by six blinded readers using ROC analysis.
  
  
  RESULTS
  Detectability of the 6-mm nodules was significantly higher in scan 2 than in scan 1. Detectability of the 10-mm nodules was not significantly different between scans 1 and 2.
  
  
  CONCLUSIONS
  The use of a smaller pitch by employing a subsecond rotation scan in a helical CT for lung cancer screenings improves the detection of small lesions without increasing either the scanning time or radiation dose.
authors.affiliation: Department of Radiology, Nagoya University Graduate School of Medicine, Japan. yoshine@jg7.so-net.ne.jp
authors.forename: Yoshine
authors.initials: Y
authors.lastname: Mori
authors.forename: Shigeki
authors.initials: S
authors.lastname: Itoh
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Ikeda
authors.forename: Akiko
authors.initials: A
authors.lastname: Sawaki
authors.forename: Koujiro
authors.initials: K
authors.lastname: Suzuki
authors.forename: Shingo
authors.initials: S
authors.lastname: Iwano
authors.forename: Hiroko
authors.initials: H
authors.lastname: Satake
authors.forename: Shoji
authors.initials: S
authors.lastname: Arahata
authors.forename: Toyohiro
authors.initials: T
authors.lastname: Ota
authors.forename: Takeo
authors.initials: T
authors.lastname: Ishigaki
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007564:Japan; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D019047:Phantoms, Imaging; D036542:Tomography, Spiral Computed / Q000379:methods*