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A quality control test for electronic portal imaging devices
Author(s) -
Rajapakshe R.,
Luchka K.,
Shalev S.
Publication year - 1996
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.597866
Subject(s) - optical transfer function , imaging phantom , image quality , image resolution , spatial frequency , contrast (vision) , calibration , noise (video) , quality (philosophy) , computer science , nuclear medicine , medical physics , optics , mathematics , statistics , physics , computer vision , medicine , image (mathematics) , quantum mechanics
A quality control (QC) test suitable for routine daily use has been developed for video based electronic portal imaging devices. It provides an objective and quantitative test for acceptable image quality on the basis of the high contrast spatial resolution and the contrast‐to‐noise ratio (CNR). The test uses a phantom consisting of five sets of high‐contrast rectangular bar patterns with spatial frequencies of 0.1, 0.2, 0.25, 0.4, and 0.75 lp/mm. Data obtained during a one month calibration period were used to determine a critical frequency f c for the relative square wave modulation transfer function and a critical contrast‐to‐noise ratio (CNR c ). Subsequent measurements indicating significant deviations from these critical values result in warning messages to the operator indicating potential problems in system performance. Measurements over a period of two years show that the QC test provides a sensitive indication of imaging performance.