Local Setup Reproducibility of the Spinal Column When Using Intensity-Modulated Radiation Therapy for Craniospinal Irradiation With Patient in Supine Position

The patient fixation used allows for deformations between the patient's skull and spine. Therefore, for the setup correction strategy evaluated in this study, generous margins for the lumbar spinal target volume are needed to prevent a local geographic miss. With any applied correction strategy, it needs to be evaluated whether or not a rotational error correction is beneficial.