For photon therapy, patient positioning is often determined using CT images acquired during treatment planning and cone beam (CB) CT images acquired at the time of treatment.3, 4, 5, 6 However, simple x‐ray images are commonly used to determine patient positioning for particle therapy at many facilities. There are also some commercial CBCT solutions for particle therapy. For example, CBCT can be included within IBA equipment, although it is probably difficult to adapt this to prevent collision with the irradiation nozzle in a facility with fixed beam lines. Thus, positioning is based on bony structures using the x‐ray images, with a certain margin added for the uncertainty of interfractional motion of the target to assure that the irradiation dose hits the target.