DC magnetic-based position and orientation monitoring system for tracking medical instruments

• US 20070078334A1
• Filed: 10/04/2005
• Published: 04/05/2007
• Est. Priority Date: 10/04/2005
• Status: Active Grant

• Current Assignee: Northern Digital Inc. (Roper Technologies, Inc.)
• Original Assignee: Ascension Technology Corporation (Roper Technologies, Inc.)
• Inventors: Schneider, Mark, Scully, Jack
• Granted Patent: US 7,835,785 B2
• Time in Patent Office: Days
• US Class Current: 600/424
• CPC Class Codes: A61B 5/06 Devices, other than using radiation, for detecting or locating foreign bodies for removing same A61B17/50 ; determining position of probes within or on the body of the patient
• CPC Class Codes: A61B 5/062 using magnetic field

Abstract

Miniaturized, five and six degrees-of-freedom magnetic sensors, responsive to pulsed DC magnetic fields waveforms generated by multiple transmitter options, provide an improved and cost-effective means of guiding medical instruments to targets inside the human body. The end result is achieved by integrating DC tracking, 3D reconstructions of pre-acquired patient scans and imaging software into a system enabling a physician to internally guide an instrument with real-time 3D vision for diagnostic and interventional purposes. The integration allows physicians to navigate within the human body by following 3D sensor tip locations superimposed on anatomical images reconstructed into 3D volumetric computer models. Sensor data can also be integrated with real-time imaging modalities, such as endoscopes, for intrabody navigation of instruments with instantaneous feedback through critical anatomy to locate and remove tissue. To meet stringent medical requirements, the system generates and senses pulsed DC magnetic fields embodied in an assemblage of miniaturized, disposable and reposable sensors functional with both dipole and co-planar transmitters.

Claims

1. Apparatus for determining the position and orientation of one or more points on a medical instrument relative to a reference frame in at least five degrees of freedom, comprising:

a) a pulsed DC magnetic field transmitter, including at least one DC magnetic field generating element;

b) a signal generation module, connected to said at least one generating element;

c) a medical instrument including at least one pulsed DC magnetic field sensor, said medical instrument being located within a body and said sensor not visible outside said body;

d) a 3D guidance electronics unit wirelessly connected to said sensor in said instrument; and

mounting means for attaching said sensor on said medical instrument;

e) said signal generation module producing one or more pulsed DC transmit signals whose pulse time is adjusted for optimal performance and providing said one or more transmit signals to elements of said DC magnetic field transmitter, said 3D guidance electronics unit wirelessly receiving said one or more detected signals from said sensor in said medical instrument, at least a portion of said one or more detected signals corresponding to said pulsed DC transmitted signal, determining position and orientation of said sensor in at least five degrees of freedom from strength of said signals, and at least a portion of said detected signal, and indicating the position and orientation of one or more points on said medical instrument.

2. The apparatus according to claim 1, wherein a number of sensor elements times a number of generating elements is at least 5 for 5 degrees-of-freedom tracking, said sensor including at least two DC magnetic field sensors.

3. The apparatus according to claim 1, wherein a number of sensor elements times a number of generating elements is at least 6 for 6 degrees-of-freedom tracking, a number of said at least one DC magnetic generating element comprising at least two elements.

4. The apparatus according to claim 1, wherein said signal generation module comprises a digital to analog converter and a signal processor connected thereto, a pulse width modulator signal processor determining a digital transmit signal, said digital to analog converter converting said digital signal to an analog signal and providing said analog signal to said at least one generating element of said pulsed DC magnetic field transmitter.

5. The apparatus according to claim 4, wherein said signal generation module is operated in accordance with a predetermined sequence.

7. The apparatus according to claim 1, further comprising:

a) an imaging modality, connected to an imaging computer, said imaging modality capturing a plurality of 2D or 3D images; and

said at least one DC sensor connected to an imaging computer, said sensor detecting position and orientation of said medical instrument,

b) wherein said imaging computer in communication with said 3D guidance electronics unit performs an operation to register image data with the said instrument within a patient;

said imaging computer performing further operation to superimpose a cursor or icon representing said instrument onto the image data of the patient'"'"'s anatomical region of interest;

said cursor or icon made to move on said image data as a function of movement of said instrument being within the patient'"'"'s anatomy; and

c) an imaging computer display operable to display the image data of the patient'"'"'s anatomical region of interest with the superimposed cursor or icon of the medical instrument in a way such that a physician can intuitively orient said instrument within the patient to the image seen on any number of computer displays.

8. The apparatus according to claim 1, further comprising:

a) an ultrasound detector, connected to an imaging computer, said ultrasound detector capturing a plurality of ultrasound frames; and

b) a position and orientation sensor that detects pulsed DC magnetic fields, mounted inor on the ultrasound detector to determine its 3D location, said position and orientation sensor detecting position and orientation of each said ultrasound frames;

c) wherein said imaging computer constructs an image from said ultrasound frames and the detected position and orientation of each of said frames with respect to the detected position and orientation of said medical instrument.

9. The apparatus according to claim 1, wherein the DC magnetic field transmitter is integrated with an optical tracking system to produce a hybrid means of continuously tracking and registering location of the magnetic transmitter when it is moved in space.

6. (canceled)

10. A medical device comprising:

a) pulsed DC magnetic field sensor means for detecting a plurality of pulsed DC magnetic fields, said sensor means located within a body and not visible outside said body;

b) a medical instrument to which said sensor means is attached; and

c) a 3D guidance electronics unit wirelessly connected to said pulsed DC magnetic sensor means;

d) an imaging computer with appropriate imaging software and memory and a display device, said imaging computer receiving signals resulting from pulsing of said magnetic fields;

e) wherein said 3D guidance electronics unit wirelessly receives pulsed DC magnetic field sensing information from said DC magnetic sensor means; and

f) wherein said 3D guidance electronics unit operates signal processing circuitry and software in association with said pulsed DC magnetic field sensing information to continuously track the DC sensor'"'"'s position and orientation within said body in at least five degrees of freedom at one or more points on or within said medical instrument whose position and orientation is thus continuously tracked.

11. The medical device according to claim 10, further comprising a pulsed DC transmitter connected to said 3D guidance electronics unit for transmitting said pulsed DC magnetic field sensing information.

12. The medical device according to claim 10, wherein said medical instrument is chosen from the group consisting of:

a) an image detection unit;

b) a substance releasing unit;

c) a biomedical sampling unit; and

d) a tool for performing procedures.

13. The medical device according to claim 10, further comprising a memory device, connected to said 3D guidance electronics unit, for storing said pulsed DC magnetic field sensing information.

14. The medical device according to claim 12, wherein said medical instrument comprises said biomedical sampling unit wherein said medical instrument provides said imaging computer with biomedical information and wherein said imaging computer produces a plurality of records including a portion of said biomedical information and a respective portion of said detected DC magnetic field information.

15. The medical device according to claim 14, further comprising a memory device, wherein said imaging computer stores said records in said memory device.

16. The medical device according to claim 10, further including a wireless pulsed DC magnetic field transmitter connected to said 3D guidance electronics unit, whereby said electronics unit provides said signals to said wireless pulsed DC magnetic field transmitter and wherein said transmitter transmits said signals to one or more DC field sensing devices.

17. The medical device according to claim 10, wherein an external pulsed DC magnetic field transmitter generates said pulsed DC magnetic fields.

18. The medical device according to claim 17, wherein said pulsed DC magnetic fields are generated by an external transmitter in accordance with a predetermined sequence.

19. The medical device according to claim 18, wherein said magnetic fields are continuously generated by said external transmitter.

20. Method for establishing a reference image onto a volume from which the image is produced, the method comprising the steps of:

a) determining a plurality of locations in said volume, said locations being visible and present in said reference image;

b) pulsing a DC magnetic field encompassing said volume;

c) sensing said pulsed DC magnetic field in each of said locations; and

d) calibrating said reference image with respect to measurements of said DC magnetic field with respect to said volume.

21. The method according to claim 20, further comprising the steps of:

a) obtaining additional pulsed DC magnetic field measurements, each in an additional location within said volume; and

b) determining position and orientation of each said additional location, within a reference frame.

22. Imaging system comprising:

a) a pulsed DC magnetic field position and orientation sensor, located in, on or in proximity of a real time ultrasound detector;

b) said ultrasound detector detecting a plurality of two-dimensional images;

c) said position and orientation sensor detecting position and orientation of each of said two-dimensional images.

23. The imaging system according to claim 22, further comprising a three dimensional image generator connected to said ultrasound detector and to said position and orientation sensor, wherein said three dimensional image generator processes said two-dimensional images, each with its respective position and orientation information, thereby producing a three dimensional image.

24. The imaging system according to claim 22, further comprising a memory device connected between said three dimensional image generator, said ultrasound detector, and said position and orientation sensor, said memory device intermediately storing said two-dimensional images, each with its respective position and orientation information.

25. The imaging system according to claim 23, further comprising an imaging computer, connected to said three dimensional image and interfacing at least one additional position and orientation sensor, wherein said imaging computer receives additional position and orientation information from said at least one additional position and orientation sensor, and wherein said imaging computer produces an image of said additional position and orientation information onto said three-dimensional image.

26. The imaging system according to claim 23, wherein said ultrasound detector includes an angular ultrasound transceiver.

27. The imaging system according to claim 22, wherein said ultrasound detector includes a radial ultrasound transceiver.

28. The imaging system according to claim 22, wherein said position and orientation sensor includes at least one axial DC magnetic sensor.

29. The imaging system according to claim 28, wherein said position and orientation sensor detects pulsed DC magnetic fields in at least one axial magnetic direction.

30. The imaging system according to claim 28, wherein said position and orientation sensor detects pulsed DC magnetic fields in at least one axial magnetic direction.

31. The imaging system according to claim 22, wherein said position and orientation sensor detects pulsed DC magnetic fields.

32. The imaging system according to claim 22, wherein said position and orientation sensor is mounted on either an internal or external body ultrasound detector.

33. The imaging system according to claim 32, wherein said ultrasound detector is mounted on a catheter and wherein said pulsed DC field position and orientation sensor is mounted on the tip or a segment of said catheter, in a vicinity of said internal body ultrasound detector.

34. The imaging system according to claim 32, wherein said internal body ultrasound detector includes an inner vascular ultrasound transceiver.

35. The imaging system according to claim 22, further comprising a position and orientation sensor mounted on a medical instrument or tool, said medical instrument or tool position and orientation sensor detecting position and orientation of said medical instrument or tool, in a coordinate system of said position and orientation sensor.

36. The imaging system according to claim 22, further comprising imaging computer means for reconstructing a three dimensional image from said two dimensional images, by placing said two dimensional images in a three dimensional volume, each according to its respective detected position and orientation.

37. The imaging system according to claim 22, further comprising a further position and orientation sensor mounted in or on a medical instrument or tool, said further position and orientation sensor detecting position and orientation of said medical instrument or tool in a coordinate system of said position and orientation sensor.

38. The imaging system according to claim 25, wherein said imaging computer further adds a representation of a medical instrument or tool onto said three dimensional image according to detected position and orientation of said medical instrument or tool.

39. Method for producing a three dimensional image, comprising the steps of:

a) detecting a plurality of two-dimensional ultrasound images, from an inner section of a scanned volume;

b) detecting position and orientation of a selected vector in each of said two dimensional ultrasound images; and

c) determining a three dimensional representation for each of said two-dimensional images, according to position and orientation thereof.

40. The method according to claim 39, further including the step of producing a three-dimensional image from each three-dimensional representation.

41. The method according to claim 40, further comprising the step of receiving additional position and orientation information and producing an indication thereof onto said three-dimensional image.

42. The method according to claim 41, further comprising the step of producing a visible representation of each said three-dimensional image and each said indication.

43. The method according to claim 39, further comprising the step of inserting an ultrasound detector into said inner section of said scanned volume.

44. The method according to claim 39, wherein said two-dimensional ultrasound images include angular two-dimensional ultrasound images.