Frequency distribution (histogram) of all anatomic landmark displacements. Of all displacement measurements, 92.4% (254/275) were 0.5 mm or less. The maximum displacement of any landmark was 1.0 mm. For both rotational and non-rotational interventions (moving in and out of scanner or leaving in place), over 90% of displacements (93.3% for rotational and 90.9% for non-rotational) were 0.5 mm or less.