Abstract: Disclosed is a cervico-thoracic orthosis and method for preventing relative motion between the cervical spine and thorax of a patient. The device bears on only certain specific local areas or sites on the surface of the thorax which are part of the thorax itself and which move only minimally relative to it. The device derives no substantial support from any site on the body which is highly movable relative to the thorax. A halo ring for engaging the skull is rigidly supported by the device.

Abstract: A special halo assembly is used with a stereotaxic device including a frame having four radiolucent substantially planar walls with radiopague indicia formed on the walls, and is operatively fixed to the frame walls by brackets to positively position the halo assembly in a predetermined position with respect to the walls. The frame is fixed with respect to a radiotherapy machine or a CT scanner. The halo assembly includes a number of brackets each having a first portion fixed to the ring component of the assembly, and a second substantially planar portion extending radially outwardly from the ring component. A method of practicing radiotherapy on a patient having a brain lesion or the like is accomplished utilizing the device. The halo assembly is surgically affixed to the patient's head to be maintained in place until all radiotherapy sessions for the patient are completed.