title: Scaling law for noise variance and spatial resolution in differential phase contrast computed tomography.
abstract: OBJECTIVE
  The noise variance versus spatial resolution relationship in differential phase contrast (DPC) projection imaging and computed tomography (CT) are derived and compared to conventional absorption-based x-ray projection imaging and CT.
  
  
  METHODS
  The scaling law for DPC-CT is theoretically derived and subsequently validated with phantom results from an experimental Talbot-Lau interferometer system.
  
  
  RESULTS
  For the DPC imaging method, the noise variance in the differential projection images follows the same inverse-square law with spatial resolution as in conventional absorption-based x-ray imaging projections. However, both in theory and experimental results, in DPC-CT the noise variance scales with spatial resolution following an inverse linear relationship with fixed slice thickness.
  
  
  CONCLUSIONS
  The scaling law in DPC-CT implies a lesser noise, and therefore dose, penalty for moving to higher spatial resolutions when compared to conventional absorption-based CT in order to maintain the same contrast-to-noise ratio.
authors: Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53705, USA.
authors: Guang-Hong
authors: GH
authors: Chen
authors: Joseph
authors: J
authors: Zambelli
authors: Ke
authors: K
authors: Li
authors: Nicholas
authors: N
authors: Bevins
authors: Zhihua
authors: Z
authors: Qi
mesh_terms: D007091:Image Processing, Computer-Assisted; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods*