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Optical Engineering

Effect Of Various Parameters On Field Uniformity Corrections In Scintillation Cameras
Author(s): Arthur J. Olch; L. Stephen Graham; J. Michael Uszler; F. Eugene Holly
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Paper Abstract

Many Anger scintillation cameras are equipped with microprocessors for live correction of field nonuniformities. The purpose of this study was to evaluate the corrected flood field uniformity after varying count rate, analyzer window size, analyzer window position, and scatter. A 2.54 cm thick Tc-99m disk source was used with large and small field Anger cameras under conditions simulating clinical usage. Uniformity was evaluated quantitatively by computing the location and percentage of cells in a 64X64 matrix that were within ±5% of the mean cell count; it was judged qualitatively by examination of the computer thresholded image. The corrected 2.54 cm thick Tc-99m disk flood image showed virtually no change in uniformity as scatter medium was increased from 0 cm to 8.9 cm. When count rate was varied from 5K to 44K cps as much as a 13% decrease in field uniformity was observed. Changing the analyzer window size produced a 5-21% decrease in uniformity while changing the window position resulted in even more significant image degradation. Knowledge of these camera characteristics is important in improving clinical images.

Paper Details

Date Published: 1 December 1980
PDF: 4 pages
Opt. Eng. 19(6) 196932 doi: 10.1117/12.7972639
Published in: Optical Engineering Volume 19, Issue 6
Show Author Affiliations
Arthur J. Olch, UCLA School of Medicine (United States)
L. Stephen Graham, UCLA School of Medicine (United States)
J. Michael Uszler, UCLA School of Medicine (United States)
F. Eugene Holly, UCLA School of Medicine (United States)

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