Patent ID: 7731667

Claim:
A biopsy needle for removal of tissue from a patient comprising: an outer tube having a distal end; an inner tube within said outer tube; and a snare having a first proximal end connected to the inner tube and a second distal end coupled to the outer tube, the snare contained within the outer tube, wherein the snare has a variable diameter that is controlled by rotation of the inner tube with respect to the outer tube in a prescribed direction resulting in the opening and closing, respectively, of the snare; wherein the outer tube has an outer surface that has a first region that terminates in the distal end and is the distalmost section of the outer tube, and a second region adjacent the first region, the first region representing a tip transition region that is defined between the distal end and an interface between the first and second regions, the interface being defined where a degree of taper of the outer tube changes, the tip transition region having a frustoconically shaped outer surface that defines a surface area (A), wherein a circular shaped area (Ba) comprises an area transecting the needle perpendicular to the longitudinal axis of the needle at a location where the first region interfaces with the second region, the interface between the first and second regions representing a base of the frustoconically shaped first region defined by a diameter of the outer tube, wherein a ratio R=(A)/(Ba) is less than or equal to 1.2 for an 8 gauge needle and less than or equal to 1.4 for an 11 gauge needle.