title: Image quality and radiation dose of low tube voltage 3rd generation dual-source coronary CT angiography in obese patients: a phantom study.
abstract: OBJECTIVE
  To assess the influence of tube potential on radiation dose and image quality of third-generation dual-source coronary CT angiography (CTA) in a phantom simulating an obese patient.
  
  
  METHODS
  A thoracic phantom was equipped with tubular inserts containing iodine solution and water. A soft-tissue-equivalent ring around the phantom simulated an obese patient. Images were acquired at tube potentials of 80, 100, 120 and 140 kV with second-generation dual-source CT (DSCT) and 70-150 kV (in 10-kV increments) with third-generation DSCT. Contrast-to-noise ratio (CNR) was calculated and CT dose index was recorded.
  
  
  RESULTS
  With second-generation DSCT, CNR was highest for 120 kV (19.0) and decreased with lower tube potential (12.0 at 80 kV) owing to disproportionately increased image noise. With third-generation DSCT, 70- and 80-kV acquisitions showed a smaller increase in noise. CNRs for third-generation DSCT were highest for 70 and 80 kV (21.1 and 21.2, respectively). Compared to 120 kV, radiation dose was 68% and 49% lower at 70 kV and 80 kV, respectively.
  
  
  CONCLUSIONS
  Third-generation DSCT enables one to perform coronary CTA at 70-80 kV in obese patients without compromising CNR and thus reduces radiation dose by 49-68%.
  
  
  CONCLUSIONS
  • Low tube potential CT angiography is currently not suitable for obese patients. • Third-generation DSCT offers substantially increased tube power at low tube potential. • This enables one to perform coronary CT angiography at 70-80 kV in obese patients. • Signal-to-noise ratio is maintained owing to increased tube current. • This approach can be expected to reduce radiation dose by 49-68%.
authors.affiliation: Department of Radiology and Radiological Science, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC, 29425-2260, USA.
authors.forename: Felix G
authors.initials: FG
authors.lastname: Meinel
authors.forename: Christian
authors.initials: C
authors.lastname: Canstein
authors.forename: U Joseph
authors.initials: UJ
authors.lastname: Schoepf
authors.forename: Martin
authors.initials: M
authors.lastname: Sedlmaier
authors.forename: Bernhard
authors.initials: B
authors.lastname: Schmidt
authors.forename: Brett S
authors.initials: BS
authors.lastname: Harris
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Flohr
authors.forename: Carlo N
authors.initials: CN
authors.lastname: De Cecco
mesh_terms: D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000150:complications / Q000000981:diagnostic imaging*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D061330:Multidetector Computed Tomography / Q000592:standards*; D009765:Obesity / Q000150:complications*; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods