System for spatially adjustable excitation of leadless miniature marker

• US 20050195084A1
• Filed: 11/23/2004
• Published: 09/08/2005
• Est. Priority Date: 12/20/2001
• Status: Active Grant

• Current Assignee: Varian Medical Systems Incorporated (Siemens AG)
• Original Assignee: Calypso Medical Technologies, Inc. (Siemens AG)
• Inventors: Wright, J. Nelson, Dimmer, Steven C., Mayo, William T.
• Granted Patent: US 7,176,798 B2
• Time in Patent Office: Days
• US Class Current: 340/572.7
• 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 leadless marker assembly, comprising:

a source generator that generates a plurality of, alternating electrical signals each having an independently adjustable phase; 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 current 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.

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 filed, 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 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 filed, 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 leadless marker assembly; and

a switching network couplable to the source generator, the switch network having a plurality of switches independently coupled to the excitation coils, the plurality of switches 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.

21-48. -48. (canceled)