Device for localizing, influencing and guiding of tracking bodies, and method for operating a marking device

• US 20070015960A1
• Filed: 01/19/2004
• Published: 01/18/2007
• Est. Priority Date: 02/28/2003
• Status: Abandoned Application

• Current Assignee: Schaerer Mayfield Technologies GmbH
• Original Assignee: Schaerer Mayfield Technologies GmbH
• Inventors: Richert, Hendryk, Heinrich, Jochen, Roder, Michael, Warschewske, Udo, Gornert, Peter
• Application Number:
  US10/547,229
• Publication Number:
  US 20070015960A1
• Time in Patent Office: Days
• US Class Current: 600/102
• CPC Class Codes: A61B 2034/107 Visualisation of planned trajectories or target regions
• CPC Class Codes: A61B 2034/2051 Electromagnetic tracking systems
• CPC Class Codes: A61B 2034/2072 Reference field transducer attached to an instrument or patient
• CPC Class Codes: A61B 2090/3954 magnetic, e.g. NMR or MRI
• 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 90/361 Image-producing devices, e.g. surgical cameras

Abstract

The invention relates to a device for localizing tracking bodies (10), comprising at least one tracking body which is placed inside a physiological structure, and a means which is situated outside of the structure and which consists of sensor clusters (20) in a sensor cluster arrangement (55) as well as a method for localizing and influencing the tracking body. The tracking body is provided in the form of a body which is characterized by a finite remanent magnetization with a variable magnetic dipole moment and an anisotropic magnetic dipole field resulting therefrom. The sensor clusters (20) are provided in the form of a plurality of gradiometer sensors (30) with a specific measuring geometry.

Optionally, physical/chemical properties and/or a trajectory of the tracking body may be altered in a specific manner by an externally acting magnetic field (H) and/or physiological processes in the environment of the at least one tracking body. In addition, it is possible to detect the location of a variable, in particular, a displaceable portion (57) which is associated with an expanded imaging means (60) of the sensor cluster arrangement (55) by means of a fixed portion (56) of the sensor cluster arrangement and to use the variable portion of the sensor cluster arrangement as a site marking in the expanded imaging arrangement.

Claims

1. Device for localizing, influencing, and guiding of tracking bodies, comprising

at least one tracking body placed inside a physiological structure, and a sensor situated outside of the physiological structure for the determination of the location of the tracking body, as well as a measuring and control unit,

at least one tracking body having a finite remanent magnetization with a variable magnetic dipole moment and an anisotropic magnetic dipole field resulting therefrom,

wherein the sensor comprises a plurality of modular sensor clusters sensitive to the anisotropic dipole field and covering a measuring range, with one each at least one of a plurality of magnetic field sensors being integrated in the sensor cluster in a specific measuring geometry,

the measuring and control unit being linked for measuring with the plurality of the sensor clusters.

2. The device according to claim 1, wherein the at least one tracking body comprises a material with a remanent magnetization as high as possible and with a coercive field strength as low as possible.

3. The device according to claim 2, wherein the at least one tracking body comprises a neodym-iron-boron composition, NdFeB, which is coated by a physiologically and magnetically neutral material.

4. The device according to claim 1, wherein the at least one tracking body forms an integral part of a medical instrument comprising a medical pointer, an endoscope, or similar other probe.

5. The device according to claim 1, wherein the at least one tracking body is configured as a freely movable object which circulates in an organism, in particular in body cavities.

6. The device according to claim 5, wherein the at least one tracking body comprises activatable and/or reactive, in particular, tissue marking portions which release substances in a controlled manner and/or similar constituents sensitive to a given physiological environment, external magnetic fields.

7. The device according to claim 1, wherein each individual sensor cluster comprises a minimum configuration of a plurality of gradiometers for a localization of the at least one tracking body, for a detection of a location in space and a detection of an orientation.

8. The device according to claim 1, wherein the individual sensor cluster comprises interfaces for the connection with a plurality of further sensor clusters.

9. The device according to claim 1, wherein the sensor cluster comprises part of a patient support, in particular as a part of head, arm, or back rests, table tops or similar means.

10. The device according to claim 1, wherein a plurality of interconnected sensor clusters forms a sensor cluster arrangement, with the sensor cluster arrangement covering an appropriate zone of the examination field.

11. The device according to claim 1, wherein the plurality of sensor clusters comprises a fixed portion and a variable, displaceable portion, with the variable portion being designed as comprising a part for position marking in an external imaging arrangement, in particular, in a magnetic resonance tomography or computerized tomography.

12. A method for localizing and influencing of a tracking body which is placed into a physiological environment, wherein

from a measured distribution of the field strength and the field direction of at least one tracking body surrounded by a magnetic dipole field, its position in space and its orientation and/or its trajectory are determined by an arrangement of at least one of a plurality of magnetic field sensors combined to a sensor cluster, and/or

optionally, physical/chemical properties and/or a trajectory of the at least one tracking body are altered in a specific manner by an externally acting magnetic field and/or physiological processes in the environment of the at least one tracking body.

13. The method according to claim 12, wherein the tracking body comprises a location reference point of a diagnostic probe and/or sensor means, in particular, of a catheter or an endoscopic device, with a movement, a current location in space, and a current orientation of the location reference point being continuously determined.

14. The method according to claim 12, wherein the tracking body as a freely movable indicator is implanted into the respective physiological environment, as an diagnostically active constituent of a suspension, with a movement, a current location in space, and a current orientation of the indicator being continuously determined by the sensor cluster arrangement.

15. The method according to claim 12, wherein the determination of the location of the tracking body is effected from measuring data via an amount and a direction of a certain vector in each individual magnetic field sensor of the sensor cluster of a magnetic field strength of the magnetic field generated by the tracking body, with initial data for an algorithm for a searching strategy for the localization of the tracking body being stored in a position determination means.

16. The method according to claim 15, wherein the algorithm for the searching strategy executes procedures for an inverse tracking, in particular adaptive gradient procedures in combination with a fuzzy evolution algorithm.

17. The method according to claim 12, wherein when using several sensor clusters a dynamic integration of the sensor clusters in the sensor cluster arrangement is performed between the sensor clusters by means of an internal communication protocol, with an optimization of the signal-noise ratio in the entire sensor cluster arrangement and an optimization of the data quantity generated by the sensor cluster arrangement being effected.

18. The method according to claim 12, wherein the magnetic moment of the at least one tracking body is influenced by externally applied magnetic field wherein its magnetization is changed, in particular, cancelled, or generated.

19. The method according to claim 12, wherein an active displacement of the at least one implanted, freely movable tracking body is effected by an externally applied magnetic field with a field vector oriented in a corresponding direction.

20. The method according to claim 12, wherein a controlled release of substances bound on the surface of the tracking body is effected by the changed magnetization of the at least one tracking body.

21. The method according to claim 12, wherein the location of a variable displaceable portion which is associated with an expanded sensor cluster arrangement is detected by a fixed portion of the sensor cluster arrangement and/or the variable portion of the sensor cluster arrangement is used as a location marker in the expanded imaging arrangement, with the location in space and the orientation of the tracking body which are determined by the sensor cluster arrangement being inserted into the generated image.