Patent ID: 7245958

Claim:
Apparatus for determining the required insertion depth for a biopsy needle priorly aligned for proper insertion into the body of a patient at a selected point on a surface of said body, so as to enter in a straight line passing through a designated target region within said body by the use of first and second image planes, such that at said proper depth, an end of said needle just reaches said target area, said apparatus comprising: a base portion including a circle portion having a center point; a planar semicircular portion mounted onto said base portion such that the diameter of said semicircular portion is concentric with said center point and rotatable thereabout, said semicircle portion being further rotatable about a straight line through said diameter; a straight pointing device having one end thereof pivotably affixed to said center point and being constrained for movement within a plane defined by said planar semicircular portion; and at least one straight pointing needle having one end thereof pivotably affixed at one end of said diameter of said semicircular portion and being constrained for movement within a plane defined by said planar semicircular portion; means for measuring an angle θ of said plane defined by said semicircular portion relative to said base portion, an angle φ of said pointing device relative to said base portion, and an angle φ 1 defined by said at least one pointing needle relative to said base portion; and a further pointing needle having one end thereof pivotably affixed at the other end of said diameter of said semicircular portion and being constrained for movement within said plane defined by said planar semicircular portion.