This frame was originally developed for invasive fixation of the spine for extracranial radiosurgery of spinal tumors (Hamilton and Lulu 1995; Hamilton et al. 1995; Hamilton et al. 1996); however, the system is very flexible and allows also the patient positioning in a vacuum pillow or a whole-body cast (Herfarth et al. 2000b, c; Lohr et al. 1999).