Ultrasound trainer with internal optical tracking

1. An ultrasound trainer, comprising:

a) a chamber defining an orifice;

b) a shaft insertable into the orifice of the chamber, the shaft having a proximal end, a distal end opposite the proximal end, a flexible tip at the distal end, and a control knob to bend the flexible tip;

c) a marker positioned on the shaft at the distal end;

d) a camera positioned to view inside the chamber towards the orifice;

e) a processor operatively connected to the camera for processing a position and an orientation of the shaft based on the marker;

f) a motion limiter connected to the chamber at the orifice, the motion limiter configured to provide tight contact with the shaft via friction;

g) a filler material inside the chamber; and

h) a light source to illuminate the chamber, wherein the chamber mimics a body.

2. An ultrasound trainer, comprising:

a) a chamber defining an orifice;

b) a shaft insertable into the orifice of the chamber, the shaft having a proximal end and a distal end opposite the proximal end;

c) a marker positioned on the shaft at the distal end;

d) a motion limiter at the orifice of the chamber, the motion limiter configured to provide tight contact with the shaft via friction;

e) a camera positioned to view inside the chamber; and

f) a processor operatively connected to the camera for processing a position and an orientation of the shaft based on the marker.

3. The ultrasound trainer of claim 2 , wherein the motion limiter is elastic.

4. The ultrasound trainer of claim 2 , further comprising a filler material inside the chamber.

5. The ultrasound trainer of claim 2 , further comprising a light source to illuminate the chamber.

6. The ultrasound trainer of claim 2 , wherein the shaft comprises a flexible tip at the distal end.

7. The ultrasound trainer of claim 6 , wherein the shaft comprises a controller to bend the flexible tip.

8. The ultrasound trainer of claim 2 , wherein the chamber mimics a body.

9. The ultrasound trainer of claim 8 , wherein the body is a vaginal area.

10. The ultrasound trainer of claim 8 , wherein the body is a rectal area.

11. The ultrasound trainer of claim 8 , wherein the body is a head and neck area.

12. The ultrasound trainer of claim 2 , wherein the motion limiter comprises rubber.

13. The ultrasound trainer of claim 2 , wherein the motion limiter is configured to constrain lateral motion of the shaft.

14. The ultrasound trainer of claim 2 , wherein the motion limiter is configured to deform when the shaft changes orientation.

15. The ultrasound trainer of claim 2 , wherein the motion limiter extends into the chamber to mimic an internal anatomy of the chamber.

16. The ultrasound trainer of claim 2 , wherein the orifice leads to a channel, wherein the orifice and channel define the motion limiter, and wherein the motion limiter is replaceable to simulate different medical procedures.

17. A method for training use of an ultrasound, comprising:

a) acquiring a chamber defining an orifice;

b) acquiring a shaft configured to be inserted into the orifice of the chamber, the shaft having a proximal end and a distal end opposite the proximal, and a marker positioned on the shaft at the distal end;

c) inserting the distal end of the shaft inside the chamber through the orifice of the chamber;

d) deforming a motion limiter while moving the shaft inside the chamber;

e) monitoring movement of the marker inside the chamber with a camera; and

f) determining a position and orientation of the shaft based on the movement of the marker with a processor operatively connected to the camera.

18. The method of claim 17 , further comprising bending a flexible tip of the shaft with a controller to view inside the chamber.

19. The method of claim 17 , wherein the position and orientation of the shaft is determined by a distortion of the marker.

20. The method of claim 17 , wherein the position and orientation of the shaft is determined using a look-up table.