Figure 3.

Daily QA parameters extracted from the Siemens SOMOTOM Definition Flash CT Scanner. Three parameters were extracted in daily QA testing performed from 1 September 2017 to 31 July 2018: HU of water, uniformity, and standard deviation. The highlighted time points shown in orange, red, and green represent 1) the designated first time point in this study (i.e., our reference scan for comparison), 2) the designated second time point in this study (i.e., the radiomics phantom scan performed when the scanner was producing an artifact), and 3) when the artifact was first identified by the radiologist, respectively. The horizontal red lines show the limit values in the scanner meeting vendor‐specific tolerances and therefore passing the daily QA testing.