title: Dual-energy computed tomography: is there a penalty in image quality and radiation dose compared with single-energy computed tomography?
abstract: OBJECTIVE
  To assess dose and image quality of dual-energy (DE) mixed images in comparison to single-energy (SE) images.
  
  
  METHODS
  A phantom containing iodine contrast inserts was scanned using SE and DE protocols. Dual-energy mixed images were reconstructed with varying composition ratios (ratio describing the contribution of 80 and 140 data in the mixed images). Image noise, iodine contrast, and contrast-to-noise ratios (CNRs) were assessed inside and outside the central field of view (FoV).
  
  
  RESULTS
  With the default composition ratio (0.3), noise and contrast were comparable between both protocols in the central FoV. Peripherally, DE image noise exceeded noise in SE images; CNR in the periphery was lower in the DE images. The highest CNR was found for a composition ratio of 0.5 to 0.9, exceeding the CNR of SE images.
  
  
  CONCLUSIONS
  Dual-energy mixed images offer an image quality comparable to SE images within the central FoV at comparable dose levels. In the peripheral FoV, image quality is decreased. By optimizing the composition ratio in the DE mixed images, higher CNRs than in the SE images can be achieved, leading to a dose reduction potential.
authors.affiliation: Department of Diagnostic and Interventional Radiology, University of Tübingen, Tübingen, Germany. christoph.thomas@med.uni-tuebingen.de
authors.forename: Christoph
authors.initials: C
authors.lastname: Thomas
authors.forename: Dominik
authors.initials: D
authors.lastname: Ketelsen
authors.forename: Ilias
authors.initials: I
authors.lastname: Tsiflikas
authors.forename: Anja
authors.initials: A
authors.lastname: Reimann
authors.forename: Harald
authors.initials: H
authors.lastname: Brodoefel
authors.forename: Claus D
authors.initials: CD
authors.lastname: Claussen
authors.forename: Martin
authors.initials: M
authors.lastname: Heuschmid
mesh_terms: D003287:Contrast Media; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007472:Iohexol / Q000031:analogs & derivatives; D016014:Linear Models; D019047:Phantoms, Imaging; D011786:Quality Control; D011829:Radiation Dosage; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide