Biopsy device with variable speed cutter advance

1. A biopsy device comprising:

an outer cannula having a lateral tissue receiving port;

an inner tubular cutter disposed for translation within the cannula;

a rotating member having a screw thread feature of varying pitch, wherein the rotating member is operatively associated with the cutter for varying the translational speed of the cutter as the tissue cutter is advanced in relation to the tissue receiving port.

2. The biopsy device of claim 1 comprising a motor for rotating the rotating member.

3. The biopsy device of claim 2 wherein the motor is an electric motor.

4. The biopsy device of claim 1 wherein the rotating member has a relatively coarse thread pitch portion and a relatively fine thread pitch portion.

5. The biopsy device of claim 1 wherein the rotating member is adapted to rotate without translation of the cutter in at least one position of the cutter.

6. The biopsy device of claim 5 wherein the rotating member is adapted to rotate without translation of the cutter when the cutter is at a position of distal most cutter travel and when the cutter is at a position of proximal most cutter travel.

7. The biopsy device of claim 5 wherein the screw thread feature is adapted at the proximal and distal ends of the screw thread feature to permit rotation of the rotating member without providing translation of the cutter.

8. The biopsy device of claim 1 comprising a cam nut supported for translation along the rotating member, wherein the cam nut engages the screw thread feature of the rotating member, and wherein the cutter is rotatably supported on the cam nut.

9. The biopsy device of claim 8 further comprising a rotation shaft for providing rotation of the cutter.

10. A biopsy device comprising:

a cannula having a lateral tissue receiving port;

a tissue cutter disposed coaxially with the cannula, the cutter adapted for translation relative to the cannula; and

a variable pitch member operatively associated with the tissue cutter for providing variation in the translational speed of the tissue cutter as the tissue cutter is advanced in relation to the tissue receiving port.

11. The biopsy device of claim 10 wherein the tissue cutter is adapted for translation and rotation relative to the cannula.

12. The biopsy device of claim 10 comprising a motor for rotating the variable pitch member.

13. The biopsy device of claim 10 wherein the variable pitch member comprises a shaft having a threaded portion of varying pitch.

14. The biopsy device of claim 10 comprising a first motor for providing rotation of the variable pitch member and a second motor for providing rotation of the cutter.

15. The biopsy device of claim 10 wherein the cutter is disposed for translation within the cannula.

16. The biopsy device of claim 10 wherein the variable pitch member comprises a relatively coarse pitch portion and a relatively fine pitch portion.

17. The biopsy device of claim 16 wherein the relatively fine pitch portion provides translation of the cutter past the tissue receiving port.

18. The biopsy device of claim 10 wherein the variable pitch member comprises a shaft having a threaded portion of varying pitch, and wherein the diameter of the shaft varies alone a length of the threaded portion.

19. A biopsy device comprising:

an outer cannula having a lateral tissue receiving port;

an inner tubular cutter disposed for translation within the cannula;

a rotating member having a screw thread feature of varying pitch, wherein the rotating member is operatively associated with the cutter for varying the translational speed of the cutter, and wherein the rotating member is adapted to rotate without translation of the cutter in at least one position of the cutter.

20. The biopsy device of claim 19 wherein the rotating member is adapted to rotate without translation of the cutter when the cutter is at a position of distal most cutter travel, and when the cutter is at a position of proximal most cutter travel.