Preliminary validation of a new variable pattern for daily quality assurance of medical image display devices

This paper reports on a comparative study between the well-established test patterns for daily quality assurance (QA) of monitors of the American Association of Medical Physicists, Task Group 18 (AAPMtg18) and the Deutsches Institut für Normung e.V (DIN), and a newly proposed variable test pattern. A characteristic of the test patterns currently used for the QA of monitors is their static nature: The same test pattern is always used. This enables a learning effect that may bias the results over time. To address this problem we have developed a variable pattern for the quality assurance of monitors (MoniQA) that allows an evaluation of contrast visibility, geometric distortion, resolution, global image quality including uniformity, and artifacts. The test pattern includes randomly generated elements intended to prevent the observer from learning the test. Examples are random characters that have to be discriminated from the background to evaluate the threshold luminance difference and variable positions of different features in the test pattern. The newly proposed test patterns were generated and visualized on different viewing stations with a software tool developed in JAVA. In this study, we validated these patterns against the well-known AAPMtg18 and DIN test patterns on 22 monitors. The results showed that the MoniQA test can indicate the same monitor problems as the other well-known patterns and is significantly quicker to evaluate than the AAPMtg18 test patterns. The MoniQA pattern is a promising alternative for daily quality control of medical viewing stations.