An immobilization system, especially for use on the human head and neck area, is described in various embodiments. The system may include a bite block immobilization system having a bite block with a dental interface releasably engageable with a plurality of teeth of a patient, and a retention mask. The dental interface releasably engages the teeth of a patient and allows very highly accurate repositioning during multiple procedures. In some embodiments, the bite block may have an integral bite block airway passage, allowing a patient to have unobstructed breathing both during molding of the retention mask and during subsequent use of the system, and may include a tongue diverter, that may, by way of example only and not to limitation, be used to divert the tongue away from a therapeutic radiation beam. Steps for utilizing the system are further described.
