yes, my suggestion is easy, but sometimes with difficult patients I guess one has to choose pragmatic and feasable solutions. When you face difficulties and you start imaging and rotating gantry back and forth, I am not sure at the end of the day if you are more precise. I am for sure not advocating for a sloppy treatment practice, and I fully agree that DICOM_BH is and has to be the gold standard, but if we like it or not, sometimes patients have a bad day and cannot cope with what you want them to do. In these (rare) situations I guess it is justified to treat, if PTV is at the proper location, even when the lung volume is not exactly what it should be. There was even a time before DIBH….