Position tracking and imaging system for use in medical applications

1. A method of monitoring a position of a medical instrument with respect to a patient's body and for displaying images of the patient's body responsive to the position of the medical instrument, said method comprising:

securing a patient reference unit from movement with respect to the patient's body while permitting the patient's body to be moved within an operating environment;

securing a remote unit from movement with respect to the medical instrument;

positioning an operating environment reference unit within the operating environment;

associating at least one field generator with at least one of the patient reference unit, the remote unit and the operating environment reference unit;

associating at least one field sensor with at least one of the patient reference unit, the remote unit and the operating environment reference unit;

generating a position characteristic field with the at least one field generator;

producing position data responsive to a sensor output signal produced by the at least one field sensor that is responsive to the presence of the position characteristic field such that the sensor output signal is representative of a position of the remote unit with respect to the patient reference unit;

obtaining image data representing a plurality of images of the patient's body; and

displaying an image of the patient's body based on the image data and responsive to position image data that varies for different position data.

2. The method of claim 1 , wherein said associating at least one field generator step comprises attaching at least one field generator to the patient reference unit; and wherein said associating at least one field sensor step comprises attaching at least one field sensor to the remote unit.

3. The method of claim 1 , wherein said associating at least one field generator step comprises attaching at least one field generator to the operating environment reference unit; and wherein said associating at least one field sensor step comprises attaching at least one field sensor to the remote unit.

4. The method of claim 1 , further comprising positioning a reference sensor a fixed distance from at least one of the at least one field generator and the at least one field sensor.

5. The method of claim 1 , further comprising generating a reference output signal for use in monitoring the position characteristic field.

6. The method of claim 1 , wherein said generating a position characteristic field comprises generating a position characteristic field that is a non-linear field that emanates from substantially a singular point.

7. The method of claim 1 , wherein said generating a position characteristic field comprises generating a position characteristic filed that is at least two time multiplexed fields that emanate from substantially the same point.

8. The method of claim 1 , further comprising registering a spatial orientation of prerecorded scan images with a spatial orientation of the position characteristic field.

9. The method of claim 1 , wherein said displaying an image step comprises displaying an indicator representative of a location of the medical instrument with respect to the patient's body.

10. A method of monitoring a position of a medical instrument with respect to a patient's body, said method comprising:

positioning a patient reference unit on a portion of the patient's body;

positioning a remote unit with respect to the medical instrument;

associating at least one field sensor with at least one of the patient reference unit and the remote unit;

generating an electromagnetic field;

producing position data responsive to a sensor output signal that is responsive to the presence of the electromagnetic field such that the sensor output signal is representative of a position of the remote unit with respect to the patient reference unit;

obtaining image data representing a plurality of images of the patient's body; and

displaying an image of the patient's body based on the image data and responsive to position image data that varies for different position data.

11. The method of claim 10 , wherein said generating an electromagnetic field step comprises generating an electromagnetic field with at least one field generator associated with at least one of the patient reference unit and the remote unit, and wherein the electromagnetic field is capable of passing through the patient's body and being substantially undisturbed by passage through the patient's body.

12. The method of claim 10 , further comprising positioning an operating environment reference unit within an operating environment; and wherein said associating at least one field sensor step comprises associating at least one field sensor with at least one of the patient reference unit, the remote unit and the operating environment reference unit.

13. The method of claim 10 , further comprising generating a reference output signal for use in monitoring the position characteristic field.

14. The method of claim 10 , wherein said generating an electromagnetic field comprises generating an electromagnetic field that is a non-linear field that emanates from substantially a singular point.

15. The method of claim 10 , wherein said generating an electromagnetic field comprises generating an electromagnetic field that is at least two time multiplexed fields that emanate from substantially the same point.

16. The method of claim 10 , further comprising registering a spatial orientation of prerecorded scan images with a spatial orientation of the electromagnetic field.

17. The method of claim 10 , wherein said displaying an image step comprises displaying an indicator representative of a location of the medical instrument with respect to the patient's body.

18. A method of monitoring a position of a medical instrument having a remote unit secured thereto with respect to a patient's body, said method comprising:

generating an electromagnetic field;

moving the medical instrument having the remote unit within the multidirectional field;

producing position data responsive to a sensor output signal that is responsive to the presence of the electromagnetic field such that the sensor output signal is representative of a position of a remote unit, which is secured to the medical instrument, with respect to a reference unit that is secured to a portion of the patient's body;

obtaining image data representing a plurality of images of the patient's body; and

displaying an image of the patient's body based on the image data and responsive to position image data that varies for different position data.

19. The method of claim 17 , wherein said generating an electromagnetic field step comprises generating an electromagnetic field with a field generator that is secured to a portion of the patient's body.

20. The method of claim 17 , wherein said displaying an image step comprises displaying an indicator representative of a location of the medical instrument with respect to the patient's body.