Reply To: kV/kV imaging in DIBH

Forums Deep Inspiration Breath Hold kV/kV imaging in DIBH Reply To: kV/kV imaging in DIBH

Marko Laaksomaa

Interesting to hear that someone else is also adjusting the breath hold level based on LAT image and vertebra. Can we go to details here or at the e-mail? Based on our experience, for the user, this kind of workflow needs lots of experience and understanding to work in the online match (kV/kV couch shift) situations. This seems to be because the isocenter and the breath hold level are not separated in the system, vertebra match does not always work perfectly if there is a need for the couch shift in the isocenter in addition to BHL. If the “AlignRT isocenter” (the acquisition position in the Offline review) is completely at the sternum match in the first place, then the vertebra match and couch shifts based on that (= BHL- correction) works well, without recapturing the surface after couch shifts. This needs patient guidance, so that the patient understands to inhale more or less to reach the same BH- deltas, because the couch has shifted based on vertebra match. The pre-defined BH- surface that AlignRT has, is in my opinion a great feature, at least for the tangential image accuracy.