title: Low-dose abdominal CT protocols with a tube voltage setting of 100 kVp or 80 kVp: Performance of radiation dose reduction and influence on visual contrast.
abstract: OBJECTIVE
  To evaluate the radiation dose, image quality, and influence on visual contrast of low tube voltage abdominal computed tomography (CT) and the effects of display setting optimization.
  
  
  METHODS
  One hundred and fifty-seven patients were randomly assigned to one of three protocols. Fifty-two patients underwent a 120 kVp protocol, and 53 and 52 patients underwent low-dose protocols with 100 and 80 kVp, respectively. The effective dose (ED), image noise, CT attenuation, and signal-to-noise ratio (SNR) of each organ of each protocol were compared using Dunnett's test. Qualitative analysis between the protocols was also performed.
  
  
  RESULTS
  The ED of the 100 and 80 kVp protocols were 22% and 37% reduced, respectively. There were no significant differences in the SNR between the protocols (120 kVp: 13.8 ± 3.5; 100 kVp: 13.9 ± 3.3; 80 kVp: 13.5 ± 2.9; p > 0.05). However, there were significant differences in contrast familiarity between the 120 kVp images and all the other images, except 100 kVp images, with optimized display settings (p < 0.05).
  
  
  CONCLUSIONS
  In abdominal CT, an 80 kVp setting offers greater radiation dose reduction than a 100 kVp setting without significant deterioration of the SNR; however, the visual contrast between the organs might be changed.
authors.affiliation: Diagnostic Radiology, Amakusa Medical Center, Kameba 854-1, Amakusa, Kumamoto 863-0046, Japan; Department of Diagnostic Radiology, Graduate School of Medical, Kumamoto University, Japan. Electronic address: kff00712@nifty.com.
authors.forename: T
authors.initials: T
authors.lastname: Nakaura
authors.affiliation: Diagnostic Radiology, Amakusa Medical Center, Kameba 854-1, Amakusa, Kumamoto 863-0046, Japan; Department of Diagnostic Radiology, Graduate School of Medical, Kumamoto University, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Kidoh
authors.affiliation: Diagnostic Radiology, Amakusa Medical Center, Kameba 854-1, Amakusa, Kumamoto 863-0046, Japan; Department of Diagnostic Radiology, Graduate School of Medical, Kumamoto University, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Nakamura
authors.affiliation: Department of Surgery, Amakusa Medical Center, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Doi
authors.affiliation: Department of Diagnostic Radiology, Graduate School of Medical, Kumamoto University, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Shiraishi
authors.affiliation: Department of Diagnostic Radiology, Graduate School of Medical, Hiroshima University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Awai
authors.affiliation: Department of Surgery, Amakusa Medical Center, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Harada
authors.affiliation: Department of Diagnostic Radiology, Graduate School of Medical, Kumamoto University, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Yamashita
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D003287:Contrast Media; D005260:Female; D006801:Humans; D007472:Iohexol; D007479:Iopamidol / Q000031:analogs & derivatives; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D011860:Radiography, Abdominal / Q000379:methods*; D059629:Signal-To-Noise Ratio; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; C057937:iomeprol; D007472:Iohexol; D007479:Iopamidol