A position determining system and method.

摘要

A patient's head is anchored (16) at one end of a patient support (10). An array of receivers (50) are mounted on a frame (12) which is fixed to the patient support. The frame carries at least one reference transmitter (52). A wand (42) has at least two emitters (44, 46)mounted thereto. By measuring relative travel time of the signals from the wand emitters to the receiver array and comparing the travel time with travel time over a known distance from the reference transmitter to one or more of the receivers, the position of the wand in a coordinate system of the patient support is determined (80). A three-dimensional array of diagnostic image data was taken through the anchored portion of the patient and at least three markers (114) affixed to the patient. By positioning the wand on the markers after the patient is secured to the patient support, a transform (110) between the patient support coordinate system and the image data coordinate system is derived. Once the relationship between the coordinate systems is known, the surgeon can use the wand to select locations and orientations on a surface of the patient and retrieve corresponding portions of the image data for display on video monitors (30).