Computed Tomography Image Formation
Outline

• Introduction and Overview
   

• The CT Imaging Process
  Scanning and data acquisition
  Image reconstruction
  Digital-to-analog conversion and viewing
   

• CT Image Characteristics
  Contrast Sensitivity
  Detail
  Spatial
   

• The X-ray Beam
  Shape (Fan)
  Thickness
  Multiple Beams
   

• Detectors
  General Description
  Function
  Configuration
  Multiple Row Detectors
   

• Scanning and Data Acquisition
  Views
  Rays
  Adjustable factors
  KV
  MAS and time
   

• Scanning Methods and Data Sets
  Scan and step slice acquisition
  Concept
  Data set characteristics
  Spiral/Helical scan volume acquisition
  Concept
  Data Set Characteristics
  Pitch
   

• Image Reconstruction
  Concept and Method
  Filtering
  Voxels and pixels
  Measurement of tissue attenuation coefficient
  Calculation of CT numbers
  Hounsfield units
  Relationship to tissue characteristics
  Scale of values
  Adjustable factors
  Field of view
  Matrix size
  Slice thickness (from Volume acquisition)
  Slice position (from Volume acquisition)
  Filter Algorithm selection

• Digital to analog image conversion
  Concept
  Windowing
  Concept
  Purpose
  Adjustable factors
  Level
  Width
  Zoom
  Concept
  Purpose