title: Variance analysis of x-ray CT sinograms in the presence of electronic noise background.
abstract: OBJECTIVE
  Low-dose x-ray computed tomography (CT) is clinically desired. Accurate noise modeling is a fundamental issue for low-dose CT image reconstruction via statistics-based sinogram restoration or statistical iterative image reconstruction. In this paper, the authors analyzed the statistical moments of low-dose CT data in the presence of electronic noise background.
  
  
  METHODS
  The authors first studied the statistical moment properties of detected signals in CT transmission domain, where the noise of detected signals is considered as quanta fluctuation upon electronic noise background. Then the authors derived, via the Taylor expansion, a new formula for the mean-variance relationship of the detected signals in CT sinogram domain, wherein the image formation becomes a linear operation between the sinogram data and the unknown image, rather than a nonlinear operation in the CT transmission domain. To get insight into the derived new formula by experiments, an anthropomorphic torso phantom was scanned repeatedly by a commercial CT scanner at five different mAs levels from 100 down to 17.
  
  
  RESULTS
  The results demonstrated that the electronic noise background is significant when low-mAs (or low-dose) scan is performed.
  
  
  CONCLUSIONS
  The influence of the electronic noise background should be considered in low-dose CT imaging.
authors: Department of Radiology, State University of New York, Stony Brook, NY, USA.
authors: Jianhua
authors: J
authors: Ma
authors: Zhengrong
authors: Z
authors: Liang
authors: Yi
authors: Y
authors: Fan
authors: Yan
authors: Y
authors: Liu
authors: Jing
authors: J
authors: Huang
authors: Wufan
authors: W
authors: Chen
authors: Hongbing
authors: H
authors: Lu
mesh_terms: D000704:Analysis of Variance; D016477:Artifacts; D003627:Data Interpretation, Statistical; D004574:Electromagnetic Fields; D004581:Electronics; D011856:Radiographic Image Enhancement / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D059629:Signal-To-Noise Ratio; D014057:Tomography, X-Ray Computed