A user based quality assurance program for assessing image quality changes in Computed Tomography is described. Measured image quality parameters include: CT number and standard deviation (noise) in a water phantom, contrast scale based on the CT number difference between plexiglass and water, and resolution as indicated by the modulation of a plastic bar pattern. For any quality assurance program to be effective, realistic values for allowable variation in image quality parameters must be established. This requires an understanding of the effect on image parameters caused by variations in the CT system parameters. In order to understand this interaction, a General Electric CT/T 8800 scanner was systematically "detuned" and image quality parameters monitored. CT system parameters studied include kVp, x-ray tube focal spot size, x-ray output, slice thickness and system alignment. The effect on the image for each system parameter is established and an attempt is made to identify system parameters whose status can be assessed by image parameter measurements.

Date Published: 13 December 1983
PDF: 9 pages
Proc. SPIE 0419, Application of Optical Instrumentation in Medicine XI, (13 December 1983);

Published in SPIE Proceedings Vol. 0419:
Application of Optical Instrumentation in Medicine XI
Gary D. Fullerton, Editor(s)