Reply To: Vertical shifts from radiographic images

Forums Deep Inspiration Breath Hold Vertical shifts from radiographic images Reply To: Vertical shifts from radiographic images

Maybe a better question to ask is, how does one know if the VRT shift indicated by the kV orthogonals is due to an actual patient misalignment, an incorrect or inconsistent BH during imaging, or both? If we always apply the shift, we could end up in a situation in which the BH will be more than 3 mm off compared to the planned BH, and this is a problem for monoisocentric setup because of the matchline between the tangents and the supraclavicular field.