title: Manual adjustment of tube voltage from 120 to 100 kVp during abdominal CT in patients with body weights ≤75 kg: assessment of image quality and radiation dose in a prospective, randomised trial.
abstract: OBJECTIVE
  To assess image quality and radiation dose in patients with body weights ≤75 kg undergoing abdominal computed tomography (CT) with a tube voltage of either 120 or 100 kVp.
  
  
  METHODS
  Eighty patients weighing ≤75 kg were prospectively assigned to receive either 120 or 100 kVp abdominal CT in the portal-venous phase. Attenuation values of abdominal organs and image noise were measured, and the contrast-to-noise ratios (CNRs) were calculated. Subjective image quality was assessed by three independent radiologists. Radiation exposure was assessed by size-specific dose estimate (SSDE).
  
  
  RESULTS
  The mean attenuation of the kidney increased by 20% at 100 kVp (p<0.0001), and the mean image noise was 27% higher in the 100 kVp (p=0.003). The CNR did not significantly differ between the groups (120 kVp, 6.6±2.8; 100 kVp, 7.4±3.6; p=0.26). Except for subjective image noise (p<0.001), no other subjective quality parameters (e.g., contrast, artefacts) were significantly different between the two groups (p between 0.094 and 0.761). The mean SSDE in the 100-kVp group (9.8±1.8 mGy) was reduced by 19% compared to the 120-kVp group (12.1±1.8 mGy; p<0.0001).
  
  
  CONCLUSIONS
  Manual reduction of tube voltage from the standard 120 to 100 kVp for portal-venous phase CT in patients with body weights ≤75 kg resulted in a 19% dose reduction while maintaining objective and subjective image quality.
authors.affiliation: Clinic of Radiology and Nuclear Medicine, University Hospital Basel, Basel, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Zaehringer
authors.affiliation: Clinic of Radiology and Nuclear Medicine, University Hospital Basel, Basel, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Euler
authors.affiliation: Clinic of Radiology and Nuclear Medicine, University Hospital Basel, Basel, Switzerland.
authors.forename: G M
authors.initials: GM
authors.lastname: Karwacki
authors.affiliation: Clinic of Radiology and Nuclear Medicine, University Hospital Basel, Basel, Switzerland.
authors.forename: J
authors.initials: J
authors.lastname: Hohmann
authors.affiliation: Clinic of Radiology and Nuclear Medicine, University Hospital Basel, Basel, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Pansini
authors.affiliation: Department of Diagnostic Radiology, Hospital Center of Biel, Biel, Switzerland.
authors.forename: Z
authors.initials: Z
authors.lastname: Szucs-Farkas
authors.affiliation: Clinic of Radiology and Nuclear Medicine, University Hospital Basel, Basel, Switzerland. Electronic address: sebastian.schindera@usb.ch.
authors.forename: S T
authors.initials: ST
authors.lastname: Schindera
mesh_terms: D001835:Body Weight; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods*; D011446:Prospective Studies; D011829:Radiation Dosage; D011835:Radiation Protection / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D011860:Radiography, Abdominal / Q000379:methods*; D011874:Radiometry / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity