Stereotactic head frame

A) Model application of a stereotactic head frame. B) Actual application of a stereotactic head frame in preparation for LINAC radiosurgery. The stereotactic head frame is immobilized to the patient by four pins that penetrate the outer skull table (arrows). Typically, the head frame placement is done under local anesthesia. Thin slice CT or MR images are obtained after head frame placement. C) The four posts of the head frame are visualized on the images. Target coordinates are derived based on mathematic calculation of the lesion location relative to axes defined by the head frame posts. The numbers on the lower left panel indicate the dose of radiation delivered to the lesion in cGy.