Are measurements in slicer calculated by the DICOM file? How do you know it is accurate?

Hi All,

When using 3d Slicer’s ruler/ markdown tools, I was wondering how the measurement is actually calculated. Is the relative scale captured in the DICOM file? (For example, how does 3D slicer know what 1mm is on each subject).

Yes, full 3D geometry (origin, spacing, axis directions) are specified in the DICOM files.