title: Validation of dual-source single-tube reconstruction as a method to obtain half-dose images to evaluate radiation dose and noise reduction: phantom and human assessment using CT colonography and sinogram-affirmed iterative reconstruction (SAFIRE).
abstract: OBJECTIVE
  To evaluate a method for obtaining half-dose CT images for observer studies evaluating lower-dose CT.
  
  
  METHODS
  Phantoms of varying sizes were scanned at multiple tube potentials using dose-matched dual-source (DS) and single-source (SS) protocols. Images from single-tube reconstruction of DS data were compared with SS images acquired at half-original CTDIvol. Thirty patients underwent supine SS and dose-matched prone DS CT colonography (CTC). Half-dose prone images were reconstructed with sinogram-affirmed iterative reconstruction (SAFIRE). Two radiologists scored image quality on 2-dimensional (2D) and 3D images.
  
  
  RESULTS
  Image noise was similar between half-dose SS images and DS images reconstructed from one tube only with tube potential of 120 kV or more for phantoms 40 cm or smaller (P < 0.05). For both readers, the patients' CTC image quality scores were more than 84% concordant between SS or DS CTC images, and half-dose-prone CTC images with SAFIRE had 84% or more concordance with routine-dose CTC except for 3D image noise.
  
  
  CONCLUSIONS
  In appropriately sized patients, DS acquisition with single-tube reconstruction can create half-dose images, permitting comparison to full-dose images. For CTC, there is comparable image quality for colonic evaluation between full-dose and half-dose images reconstructed with SAFIRE.
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, MN, USA. fletcher.joel@mayo.edu
authors.forename: Joel G
authors.initials: JG
authors.lastname: Fletcher
authors.forename: Katharine L R
authors.initials: KL
authors.lastname: Grant
authors.forename: Jeff L
authors.initials: JL
authors.lastname: Fidler
authors.forename: Maria
authors.initials: M
authors.lastname: Shiung
authors.forename: Lifeng
authors.initials: L
authors.lastname: Yu
authors.forename: Jia
authors.initials: J
authors.lastname: Wang
authors.forename: Bernhard
authors.initials: B
authors.lastname: Schmidt
authors.forename: Thomas
authors.initials: T
authors.lastname: Allmendinger
authors.forename: Cynthia H
authors.initials: CH
authors.lastname: McCollough
mesh_terms: D023881:Colonography, Computed Tomographic / Q000379:methods*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D059629:Signal-To-Noise Ratio; D018709:Statistics, Nonparametric