Comparison of Definitions of Geometric Efficiency in Computed Tomography Scanners
Z-axis geometric efficiency in CT
Geometric efficiency (g.eff.)
Slide 4
Definitions for z-axis geometric efficiency (g.eff.)
Definitions – paraphrased
Purpose of this study
Methods of measurement – dose profiles
Methods of measurement – imaged slice width
Problems with old g.eff.
Problems with old g.eff. (continued)
Potential problems for calculation of new g.eff.
Two approaches for new g.eff. calculation
Two approaches for new g.eff. calculation (2)
Results
Single slice - old g.eff. (imaged width / dose width)
Single slice -new g.eff. (dose in nominal width/whole profile)
Multi slice - old g.eff. (imaged width / dose width)
Multi slice - old g.eff. (continued)
Multi slice - new g.eff. (dose in nominal width/whole profile)
Multi slice - new g.eff. versus old g.eff.
Conclusions
Author: Sue Edyvean
E-mail: sue@impactscan.org
Homepage: http://www.impactscan.org/