System for spatially adjustable excitation of leadless miniature marker

• US 7,696,876 B2
• Filed: 01/26/2007
• Issued: 04/13/2010
• Est. Priority Date: 12/20/2001
• Status: Expired due to Term

• Current Assignee: Varian Medical Systems Incorporated (Siemens AG)
• Original Assignee: Calypso Medical Technologies, Inc. (Siemens AG)
• Inventors: Mayo, William T., Wright, J. Nelson, Dimmer, Steven C.
• Primary Examiner(s): Mullen; Thomas J
• Application Number:
  US11/627,693
• Publication Number:
  US 20080001756A1
• Time in Patent Office: 1,173 Days
• Field of Search: 340/572.1, 340/572.4, 340/572.5, 340/572.7, 343/742, 343/867
• US Class Current: 340/572.1
• CPC Class Codes: A61B 2017/00154 pulsed
• CPC Class Codes: A61B 2017/00411 actuated by application of energy from an energy source outside the body
• CPC Class Codes: A61B 2034/2051 Electromagnetic tracking systems
• CPC Class Codes: A61B 2090/3958 emitting a signal
• CPC Class Codes: A61B 2090/3975 active
• CPC Class Codes: A61B 34/20 Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
• 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
• CPC Class Codes: A61B 90/36 Image-producing devices or illumination devices not otherwise provided for
• CPC Class Codes: A61N 2005/1051 using an active marker markers in general A61B90/39
• CPC Class Codes: A61N 5/1049 for verifying the position of the patient with respect to the radiation beam
• CPC Class Codes: G08B 13/2414 using inductive tags
• CPC Class Codes: H01Q 7/08 Ferrite rod or like elongated core

Abstract

A system for generating a magnetic field for excitation of a leadless marker assembly. The system of at least one embodiment includes a source generator that generates a plurality of alternating electrical signals each having an independently adjustable phase. A plurality of excitation coils are configured to simultaneously receive a respective one of the alternating electrical signals at a selected phase to generate a magnetic field. The phase of the alternating electrical signal for each excitation coil is independently adjustable relative to the phase of the alternating electrical signal for the other excitation coils so as to adjust the magnetic field from the respective coil. The magnetic fields from the excitation coils combine to form a spatially adjustable excitation field for excitation of the remote leadless marker assembly.

Claims

1. A system for generating a spatially adjustable excitation field for excitation of a remote lead less marker assembly, comprising:

a source generator that generates a plurality of alternating electrical signals each having an independently adjustable phase, the source generator including a switch network having a plurality of H-bridge switch assemblies; and

a plurality of excitation coils being configured to simultaneously receive a respective one of the alternating electrical signals at a selected phase to generate a magnetic field;

the phase of the alternating electrical signal for each excitation coil being independently adjustable relative to the phase of the alternating electrical signal for the other ones of the excitation coils to adjust the magnetic field from the respective coil; and

the magnetic fields from the excitation coils being combined to form a spatially adjustable excitation field for excitation of the remote leadless marker assembly.

2. The system of claim 1 wherein the excitation coils are co-planar.

3. The system of claim 1 wherein the coil axes of at least two excitation coils are parallel.

4. The system of claim 1 wherein the coil axes of at least two excitation coils are non-concentric.

5. The system of claim 1 wherein the plurality of excitation coils includes four co-planar excitation coils.

6. The system of claim 1 wherein the alternating electrical signal for each coil is non-sinusoidal.

7. The system of claim 1 wherein the plurality of excitation coils include four side-by-side excitation coils each having straight sides parallel to at least one side of two other of the excitation coils.

8. The system of claim 1 wherein the plurality of excitation coils includes at least two co-planar excitation coils.

9. The system of claim 1 wherein the excitation coils are mounted on a substantially planar substrate.

10. The system of claim 1 wherein the excitation coils include first and second excitation coils, the first excitation coil being configured to receive an alternating electrical signal with a first selected phase to generate a first magnetic field, and the second excitation coil being configured to receive an alternating electrical signal with the first selected phase to generate a second magnetic field to combine with the first magnetic field to generate a first shaped excitation field, and the second excitation coil being configured to receive an alternating electrical signal with a second selected phase substantially different from the first selected phase to form a third magnetic field that combines with the first magnetic field to form a second excitation field with different spatial characteristics than the first excitation field.

11. A system for generating a spatially adjustable excitation field for excitation of a leadless marker assembly, the system being connectable to a source generator that generates a plurality of alternating electrical signals having independently adjustable phases, the system comprising:

a leadless marker assembly; and

a plurality of excitation coils remote from the leadless marker assembly, each excitation coil being independently coupled to the source generator, the source generator including a switch network having a plurality of H-bridge switch assemblies;

the excitation coils being configured to simultaneously receive a respective one of the alternating electrical signals at a selected phase to generate a magnetic field,

the phase of the alternating electrical signal for each excitation coil being independently adjustable relative to the phase of the alternating electrical signal for the other ones of the excitation coils to adjust the magnetic field from the respective coil;

the magnetic fields from the excitation coils being combined to form a spatially adjustable excitation field for excitation of the remote leadless marker assembly.

12. The system of claim 11 wherein the excitation coils are co-planar.

13. The system of claim 11 wherein the plurality of excitation coils includes four co-planar excitation coils.

14. The system of claim 11 wherein the coil axes of at least two excitation coils are parallel.

15. The system of claim 11 wherein the coil axes of at least two excitation coils are non-concentric.

16. The system of claim 11 wherein the plurality of excitation coils includes at least two co-planar excitation coils.

17. The system of claim 11 wherein the excitation coils are mounted on a substantially planar substrate.

18. The system of claim 11 wherein the excitation coils include first and second excitation coils, the first excitation coil being configured to receive an alternating electrical signal with a first selected phase to generate a first magnetic field, and the second excitation coil being configured to receive an alternating electrical signal with the first selected phase to generate a second magnetic field to combine with the first magnetic field to generate a first shaped excitation field, and the second excitation coil being configured to receive an alternating electrical signal with a second selected phase substantially different from the first selected phase to form a third magnetic field that combines with the first magnetic field to form a second excitation field with different spatial characteristics than the first excitation field.

19. A system for generating an excitation field for excitation of a leadless marker assembly, the system being connectable to a source generator that generates a plurality of alternating electrical signals having an independently adjustable phase, the system comprising:

a plurality of excitation coils configured to generate a magnetic field for excitation of the lead less marker assembly; and

a switching network couplable to the source generator, the switching network having a plurality of H-bridge switch assemblies independently coupled to the excitation coils, the plurality of switch assemblies being configured to selectively direct electrical signals through respective ones of the excitation coils to independently generate an alternating magnetic field with a selected phase for each excitation coil; and

the magnetic fields from the excitation coils being combined to form a spatially adjustable excitation field for excitation of the remote leadless marker assembly.

20. The system of claim 19 wherein the excitation coils are co-planar.

21. The system of claim 19 wherein the coil axes of at least two excitation coils are parallel.

22. The system of claim 19 wherein the coil axes of at least two excitation coils are non-concentric.

23. The system of claim 19 wherein the alternating electrical current for each coil is non-sinusoidal.

24. The system of claim 19 wherein the plurality of excitation coils include four side-by-side excitation coils each having straight sides parallel to at least one side of two other of the excitation coils.

25. The system of claim 19 wherein the excitation coils include first and second excitation coils, the first excitation coil being configured to receive an alternating electrical signal with a first selected phase to generate a first magnetic field, and the second excitation coil being configured to receive an alternating electrical signal with the first selected phase to generate a second magnetic field to combine with the first magnetic field to generate a first shaped excitation field, and the second excitation coil being configured to receive an alternating electrical signal with a second selected phase substantially different from the first selected phase to form a third magnetic field that combines with the first magnetic field to form a second excitation field with different spatial characteristics than the first excitation field.

26. The system of claim 19, further comprising an energy storage device coupled to the switching network.

27. A system for generating an excitation field for excitation of a lead less marker assembly, the system comprising:

an energy storage device;

a switching network coupled to the energy storage device, the switching network having a plurality of H-bridge switch assemblies;

a plurality of excitation coils each coupled to the switching network, each of the excitation coils having a coil axis non-concentric with the coil axis of other ones of the excitation coils each excitation coil being configured to simultaneously receive from the switching network alternating electrical signals with a selected voltage and independently adjustable phase to generate a magnetic field from the respective coil, the switching network being manipulatable to independently change the phase for each excitation coil, the magnetic fields from the excitation coils being configured to combine with each other to form an modifiable excitation field having selected spatial characteristics, for excitation of the leadless marker assembly.

28. The system of claim 27 wherein the excitation coils are connected to a substantially planar substrate.

29. The system of claim 27 wherein the excitation coils are co-planar.

30. The system of claim 27 wherein the coil axes of at least two excitation coils are parallel.

31. The system of claim 27 wherein the excitation coils include first and second excitation coils, the first excitation coil being configured to receive an alternating electrical signal with a first selected phase to generate a first magnetic field, and the second excitation coil being configured to receive an alternating electrical signal with the first selected phase to generate a second magnetic field to combine with the first magnetic field to generate a first shaped excitation field, and the second excitation coil being configured to receive an alternating electrical signal with a second selected phase substantially different from the first selected phase to form a third magnetic field that combines with the first magnetic field to form a second excitation field with different spatial characteristics than the first excitation field.

32. The system of claim 27 wherein the switching network includes at least one switch for each of the excitation coils, and each switch being configured to change a coil electrical signal phase for its respective excitation coil independent of the coil electrical signal phase of the other excitation coils.

33. A marker system, comprising:

a plurality of leadless resonating marker assemblies being excitable by a magnetic excitation signal and being configured to generate marker resonant signals at one or more selected resonant frequencies;

a plurality of location sensors remote from the marker assemblies and configured to receive the marker signals; and

a source generator assembly having an energy storage device, first and second switching networks with H-bridge switch assemblies, the first and second switching networks connected to an energy storage device, and first and second excitation coils, and the first switching network and first excitation coil being interconnected and being independent of the second excitation coil, and the second switching network and the second excitation coil being interconnected and independent of the first excitation coil.

34. The system of claim 33 wherein the switching network includes at least one switch for each of the excitation coils, and each switch being configured to change a coil electrical signal phase for its respective excitation coil independent of the coil electrical signal phase of the other excitation coils.

35. A system for generating a spatially adjustable excitation field for excitation of a remote leadless marker assembly, comprising:

a means for generating a plurality of alternating electrical signals having independently adjustable phases; and

a plurality of means for generating a magnetic field each coupled to the alternating electrical signal generating means,

the means for generating a magnetic field being configured to receive a respective one of the alternating electrical signals at a selected phase to generate a magnetic field,

the phase of the alternating electrical signal for each means for generating a magnetic field being independently adjustable relative to the phase of the alternating electrical signal for the other ones of the means for generating a magnetic field;

the magnetic fields from the plurality of means for generating a magnetic field being combined to form a spatially adjustable excitation field for excitation of the remote leadless marker assembly.

36. The system of claim 35 wherein the plurality of means for generating a magnetic field are co-planar.

37. The system of claim 35 wherein the primary axes of at least two means for generating a magnetic field are parallel.

38. The system of claim 35 wherein the plurality of means for generating a magnetic field are a plurality of excitation coils substantially adjacent to each other.

39. The system of claim 35 wherein the plurality of means for generating a magnetic field are mounted on a substantially planar substrate.

40. A system for generating a spatially adjustable excitation field for excitation of a leadless marker assembly, the system being connectable to a source generator that generates a plurality of alternating electrical signals having an independently adjustable phase, the system comprising:

a leadless marker assembly; and

a plurality of means for generating a magnetic field remote from the leadless marker assembly, each means for generating a magnetic field being couplable to the source generator, wherein the source generator includes a switch network having a plurality of H-bridge switch assemblies;

the means for generating a magnetic field being configured to simultaneously receive a respective one of the alternating electrical signals at a selected phase to generate a magnetic field, the phase of the alternating electrical signal for each means for generating a magnetic field being independently adjustable relative to the phase of the alternating electrical signal for the other ones of the means;

the magnetic fields from the means for generating a magnetic field being combined to form a spatially adjustable excitation field for excitation of the remote lead less marker assembly.

41. The system of claim 40 wherein the plurality of means for generating a magnetic field are co-planar.

42. The system of claim 40 wherein the coil axes of at least two means for generating a magnetic field are non-concentric.

43. The system of claim 40 wherein the plurality of means for generating a magnetic field includes at least two co-planar excitation coils.

44. The system of claim 40 wherein the means for generating a magnetic field are mounted on a substantially planar substrate.