Apparatus for use in stereotactic surgery

Claim 1

Apparatus for use in performing stereotactic surgery in conjunction with an X-ray CT scanner capable of measuring relative X-ray absorption within elemental volumes of a desired cross-section of the anatomy of a living patient and also defining a first three-dimensional CT-scanner coordinate system for locating specific anatomical positions within said cross-section relative to said first coordinate system, said apparatus comprising: A stereotactic frame defining a second three-dimensional coordinate system which can be fixed with respect to the anatomy of a living patient, said stereotactic frame including mechanism for positioning a desired surgical device within said anatomy at any desired location defined in terms of said second three-dimensional coordinate system, and X-ray detectable fiducial markers associated with said stereotactic frame defining at least three non-ccllinear points within each-of said cross-sections, each point having, determinable coordinates in both said first and said second coordinate systems such that the measured CT scan coordinates of a desired portion of the anatomy can be transformed to corresponding coordinates in said second coordinate system thereby facilitating the use of said stereotactic frame during stereotactic surgery.

Claim 6

A method to facilitate stereotactic surgery, said method comprising the steps of: fixing a stereotactic surgical frame, having a predetermined three-dimensional coordinate system, with respect to living tissue, scanning the combination of said frame and living tissue with penetrating radiation to provide a cross-sectional depiction thereof in a plane which includes a desired anatomical target within said living tissue, determining the coordinates of said target with respect to a second predetermined three-dimensional coordinate system, determining the coordinates of each of at least three non-collinear points located within said cross-sectional depiction, both with respect to the three-dimensional coordinate system of said frame and with respect to said second three-dimensional coordinate system, and using said determined coordinates to calculate the coordinates of said target with respect to the three-dimensional coordinate system of said frame.

Claim 7

A method to facilitate stereotactic surgery, said method comprising the steps of: fixing a stereotactic surgical frame, having a predetermined three-dimensional coordinate system, with respect to living tissue, scanning the combination of said frame and living tissue with penetrating radiation to provide a cross-sectional depiction thereof in a plane which includes a desired anatomical target within said living tissue, determining the coordinates of said target with respect to a second predetermined three-dimensional coordinate system, determining the coordinates of each of at least three non-collinear points located within said cross-sectional depiction, both with respect to the three-dimensional coordinate system of said frame and with respect to said second three-dimensional coordinate system, and using said determined coordinates to calculate the coordinates of said target with respect to the three-dimensional coordinate system of said frame.