You can calibrate the current image, series, or study to more accurately translate dimensions from pixels to real-world measurements. Such user image calibration takes precedence over any other type of calibration.
And as required, you can undo the user image calibration and revert to modality calibration.
To revert to modality calibration
From the Image area context or top toolbar, click User Image Calibration.
or
If using the context toolbar text menu (Ctrl + right-click), select Markup > User Image Calibration.
Click any two points on the image.
A calibration line appears.
To set the calibration line, right-click.
Under Scope, select whether to apply modality calibration to the Image, Series, or Study.
Under Calibration Source, select Modality.
If you cannot select Modality, modality calibration information is not available to this study.
Click Save.
Modality calibration is now in effect for the current image, series, or study. The status bar indicates a modality as the calibration source. New measurements are no longer suffixed with (ui). The Zoom True Size display of images is also affected.