EP1603456A1

EP1603456A1 - Device for localizing, influencing and guiding tracking bodies, and method for operating a marking device

Info

Publication number: EP1603456A1
Application number: EP04703175A
Authority: EP
Inventors: Peter GÖRNERT; Jochen Heinrich; Hendryk Richert; Michael Röder; Udo Warschewske
Original assignee: Schaerer Mayfield Technologies GmbH
Current assignee: Vivoguide Ltd
Priority date: 2003-02-28
Filing date: 2004-01-19
Publication date: 2005-12-14
Also published as: WO2004075749A1; US20070015960A1; JP2006519041A; CA2517250A1

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 device, which is situated outside of the structure and which consists of sensor clusters (20) in a sensor cluster arrangement (55). The invention also relates to a method for localizing and influencing the tracking body. The tracking body is provided in the form of a body, which is distinguished with regard to a finite remanent magnetization and which has a variable magnetic dipole moment and an anisotropic magnetic dipole field resulting therefrom. The sensor clusters (20) are provided in the form of an aggregate of gradiometer sensors (30) with a specific measuring geometry. Optionally, physical/chemical properties and/or a trajectory of the tracking body can be altered in a specific manner by an externally acting magnetic field (H) and/or physiological processes in the surroundings of the at least one tracking body can be altered in a specific manner. In addition a fixed component (56) of the sensor cluster arrangement (55) can detect the position of a variable, in particular, displaceable component (57) of the sensor cluster arrangement (55), said component being assigned to an expanded imaging device (60), and the variable component of the sensor cluster arrangement can be used as a location marking in the expanded imaging device.

Description

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

description

The invention relates to a device for localizing, influencing and guiding tracking bodies and a method for operating the marking device.

Marking devices in connection with tracking bodies are used in medical-biological applications for the targeted marking of physiological structures or for marking orientation points in operating fields. Such devices are often combined with imaging methods. The tracking bodies are designed in such a way that their location and their location within an operating field can be clearly identified using suitable examination methods. The path resulting from the chronological sequence and the changes in the location of the tracking body in an organism is called a trajectory. This is recorded and analyzed, whereby conclusions can be drawn about functional sequences in an organ system that the tracking body has passed or is currently passing through. An example of this is swallowing a capsule that shows an identifiable contrast in an X-ray image. From the position and passage times of the contrast structure produced by the capsule in the X-ray image, conclusions can be drawn about the activity of the digestive tract and digestive disorders.

Such a method can be designed to be minimally invasive, among other things, by the tracking body emitting the magnetic field of a magnetic dipole, which is measured. The position of the magnetic dipole is determined on the basis of the measurement data. For this purpose, the magnetic dipole field is monitored and evaluated with magnetic field sensors, which enable a resolution down to a few nanotesla. With a magnetic dipole sample of approximately 0.08 Am ² , such a method can achieve a spatial resolution of approximately 1 mm and an orientation resolution of approximately 0.1 degrees in real time (distance sensor-mar- 15 cm). Such a tracking method does not require any additional energy to activate the tracking body and places a negligible burden on the patient's organism.

The previously used embodiments of such a tracking method are still relatively limited in their area of application. Thus, according to the prior art, an inflexible sensor construction is used, which consists of an essentially rectangular plate, which is arranged at a fixed distance from an underlying patient. Such sensor constructions detect a more or less fixedly specified area. In connection with a tracking body with a fixed magnetization, the possible uses of such a tracking method are essentially limited to tracking a passage of the tracking body through a predetermined body cavity, for example the intestine.

The task thus arises to develop the described method in such a way that increased flexibility of the tracking method can be achieved by means of improved sensors, a higher measurement accuracy associated therewith and further miniaturization of both the sensors and the tracking body, whereby In particular, possibilities for a targeted and minimally invasive influence on the tracking body from the outside and an expanded functionality of the tracking body must be created.

The object is achieved with a device for localizing tracking bodies with the features of claim 1 and a method for localizing and influencing at least one tracking body introduced into a physiological environment with the features of claim 12, the subclaims expedient embodiments of the device - and the main procedural claim.

According to the invention, the marking device has a tracking body in the form of a body distinguished by finite remanent magnetization with a changeable magnetic dipole moment and a resulting anisotropic magnetic dipole field. According to the invention, the sensor device is in the form of a set of measuring, sensitive to the anisotropic dipole field. modular sensor clusters covering the area, whereby a set of gradiometer sensors is integrated in a specific measuring geometry in each sensor cluster. A measuring and control unit is connected to the entirety of the sensor clusters.

Each sensor cluster represents a detector unit, with the help of which the position of the tracking body in space and its orientation can be determined on the basis of the registered magnetic dipole field. For this purpose, the individual sensor cluster has a totality of gradiometers in an expedient geometric arrangement with respect to one another with shape limitations that are variable per se. According to the invention, several sensor clusters are combined in such a way that they optimally cover a required examination field. The resultant sensor cluster arrangement results in a kind of “mosaic” of different sensor clusters, which can be flexibly adapted to a body shape of a subject and in particular can be guided around the subject and thus appropriately captures a spatial area. The individual sensor clusters can be combined and measured in a largely arbitrary manner The measuring and control device monitors and controls the operation of the respective sensor cluster arrangement formed thereby.

The tracking body is made of a material with the highest possible remanence magnetization and the lowest possible coercive force. The material of the tracking body accordingly has a magnetization hysteresis which is stretched in the direction of the magnetization axis and narrow in the direction of the external field strength. This ensures that, on the one hand, the magnetization of the tracking body is particularly strong when the external magnetic field is switched off, a high magnetic dipole moment is generated, but, on the other hand, the magnetization can be canceled again by a relatively weak external reversing magnetic field.

Appropriately, tracking bodies made of a neodymium-iron-boron compound (NdFeB), AlNiCo and various iron alloys are preferred, which can be coated with a physiologically and magnetically neutral material. The tracking body itself can be in two basic embodiments. In a first embodiment, this forms an integral part of a medical instrument, in particular a pointer device, an endoscope or a comparable medical probe device. In a second embodiment, it is designed as an object that is movable in an organism, in particular in body cavities.

In the first embodiment, the tracking body forms a pointer device which is linked to the corresponding instrument and whose position and orientation are detected with the aid of the sensor cluster arrangement. A great advantage of such a pointer device is that the detected measurement signal (the magnetic field strength of the dipole) is generated in the form of an external excitation or wiring and is detected in a simple manner without the supply of energy. The exact location e.g. of an endoscope can be determined with high accuracy outside of the subject's body under these conditions. The second

In one embodiment, the tracking body moves freely within an implantation area and serves as an autonomous probe for the physiological conditions prevailing there, which can optionally be influenced externally.

The tracking body has sections which have properties which can be activated and / or reactive, in particular tissue-marking or controlled substances releasing substances, and / or the like, further properties which are sensitive to a given physiological environment and / or external influences, in particular external magnetic fields. According to this training, the tracking body is designed as a means of transport for substances which are released under a certain physiological environment or as a result of an influence which is specifically applied from the outside, in particular a magnetic field. Therewith therapeutically or diagnostically active substances can be brought to the place of action and released there in a controlled manner. As a minimum configuration, the sensor cluster mentioned has an entirety of gradiometers for localizing at least one tracking body, in particular its detection of a position in a three-dimensional coordinate system and its angular orientation. The individual sensor cluster thus represents the smallest detector unit of the marking system. For coupling the individual sensor cluster to a larger sensor cluster arrangement, this has interfaces for interconnection with the further sensor clusters. This either creates a larger total of gradiometers distributed over at least two sensor clusters, or the sensor clusters interact as a network via exchanged control signals.

Sensor cluster arrangements which are designed as part of a test person's bed, for example a lying surface, a head, arm or backrest, a table top or comparable devices, are particularly advantageous. Sensor cluster arrangements of this type can thus be carried out “hidden” and increase the comfort for the patient and fit into an existing device architecture in a space-saving manner. The sensor cluster arrangement covers in any case an expedient area of the examination field.

Two-part embodiments of the sensor cluster arrangement are particularly advantageous. Such embodiments have a fixed component and a variably arranged and variable-position component. The variable component is arranged here as a component for marking the position of an external device, for example a further diagnostic device, such as in the objective of a microscope. The position of the variable portion of the sensor cluster arrangement is detected by the permanently installed sensor cluster arrangement and thus the location of the higher-level external diagnostic device with respect to the system tracking body / sensor cluster arrangement is precisely coordinated and adjusted.

In a method for localizing and influencing at least one tracking body introduced into a physiological environment, with the aid of an arrangement of at least one set of gradiometer sensors combined in a sensor cluster, a measured distribution of a field strength and field direction of the at least one tract surrounded by a magnetic dipole field is used. cking body determines its position in space and its orientation and / or its trajectory. The position determination is optionally combined with a targeted influencing and changing physical / chemical properties of the tracking body or the trajectory of the tracking body by means of an externally acting magnetic field. On the one hand, the tracking body is localized with a high degree of accuracy in the examination area, on the other hand, it also creates the possibility, in conjunction with the high detection accuracy, to influence the physiological milieu present there in a targeted and minimally invasive manner in implantation areas that are difficult to access by targeting the tracking body is influenced from the outside.

In a first embodiment of the method, the tracking body is designed as a position reference point of a diagnostic probe device, in particular a catheter or an endoscopic device, movement, a current position in space and a current orientation of the position reference point of the probe device being continuously detected by the sensor cluster arrangement , Minimally invasive tracking of such a medical instrument is thus possible.

In a further embodiment of the method, the tracking body is used as a freely movable indicator in the corresponding physiological environment, for example as part of a suspension, its movement, its current position in space and a current orientation of the indicator being continuously determined by the sensor cluster arrangement ,

To determine the position of the tracking body, measurement data about an amount and a direction of a vector of a magnetic field strength determined in each individual gradiometer sensor of the sensor cluster are measured. These form the starting data for an algorithm for a search strategy for localizing the tracking body stored in a position determining device. The algorithm of the search strategy executes methods for inverse tracking, in particular adaptive gradient methods in combination with a fuzzy evolution algorithm.

If several sensor clusters are used in a sensor cluster arrangement, a dynamic integration of the sensor clusters in the sensor cluster arrangement is carried out by means of an internal communication protocol between the sensor clusters. In particular, the signal-to-noise ratio in the entire transmission Sor cluster arrangement and the amount of data generated by the sensor cluster arrangement are optimized.

External influencing of the tracking body takes place in several ways. In a first embodiment, the magnetic moment of the tracking body is influenced by means of an externally supplied magnetic field in such a way that its magnetization is changed and in particular deleted. There is thus an optional activation and deactivation of the tracking body.

In a further embodiment of the influencing of the tracking body, the trajectory of the tracking body is actively displaced by means of an externally supplied magnetic gradient field with a field gradient pointing in a corresponding direction, and the implanted tracking body or a tracking body designed with a helical surface moved in a corresponding direction in a rotating magnetic field.

All of the above-mentioned embodiments of the external tracking body influencing can be carried out individually, but also in combination. They can also be linked to a targeted release of substances bound by the tracking body. As a result of the changed magnetization of the tracking body, changed binding properties are generated on its surface and surface-bound substances are released in a controlled manner. The combination of the methods mentioned makes it possible to use the tracking body either for purely diagnostic purposes or as a pointer, but also to use it for a targeted transport of active substances within an implantation field and thus to considerably expand the applicability of the tracking method.

The device according to the invention and the method according to the invention will be explained in more detail below on the basis of exemplary embodiments. Figures 1 to 5 serve for clarification. The same reference numerals are used for identical or identically acting components. In detail shows:

1 is a schematic representation of a tracking body in an external magnetic field, Fig. 2a is a schematic representation of a first embodiment of a

Sensor cluster,

2b is a schematic representation of a second embodiment of a sensor cluster,

2c shows an exemplary representation of a sensor cluster in a spatial, spherical gradiometer geometry

3a shows a schematic representation of a position of a free tracking body in space with measured variables to be determined,

3b is a schematic representation of a tracking body integrated in a probe head of an endoscopic instrument,

Fig. 4 shows an exemplary arrangement of a sensor cluster, an outer

Magnetic field coil and a measuring and control device on a first examination object,

5 shows an exemplary arrangement of a fixed and variable sensor cluster in connection with an endoscopic arrangement and an external device for computer tomography for monitoring a cardiac catheter.

1 shows an exemplary embodiment of a tracking body 10 according to the invention. The tracking body consists of a magnetizable base body 11, which has a casing made of an activatable section 12 on its surface. The base body 11 is preferably made of a ferromagnetic material and expediently has a high residual magnetization in connection with a coercive field strength that is as easy as possible to achieve by a given coil arrangement. As a result of the finite remanence, the base body has a magnetic moment m, the position of which is determined in an external coordinate system. The base body is optionally magnetized by means of an external magnetic field H or demagnetized by applying the coercive field strength, the magnetic moment being able to be activated or deleted as desired. Such a process is referred to below as Hc switching. Since the Hc switching changes the magnetic properties of the base body, the interaction between the base body 11 and the activatable section 12 also undergoes a change, in particular with regard to specifically selected molecules. Under the influence of Hc switching, the activatable section either absorbs molecules from an environment through adsorption or absorption processes, or releases previously bound molecules and substances and releases them into the immediate vicinity of the tracking body.

Furthermore, the tracking body aligns itself with a finite remanence under the influence of the external magnetic field H and its position is changed as a function of the external magnetic field. The free tracking body can thus be moved along a predefined trajectory under the influence of the external field. In connection with the Hc switching process and the changed absorption capacity of the activatable section, there is thus the possibility of using the tracking body as a means of transporting an active substance. The tracking body is first moved and placed under the influence of the external magnetic field H to a precisely defined location within a physiological environment and then releases an active substance or takes a substance at a precisely defined point in time under the influence of Hc switching from the environment.

The size of the tracking body typically used in the following exemplary embodiments can in principle be varied within a wide range. Typical embodiments have a cylindrical basic body shape with a diameter of less than 1 mm and a length of less than 2 mm, whereby miniaturized embodiments with a diameter of less than 0.5 mm and a length of less than 1 mm are also conceivable. The size actually used for specific purposes depends on the respective conditions of use. Above all, the choice must be made of the magnetic moment that can be achieved for interference-free detection and / or influencing of the tracking body given the dimensions, the sensitivity of the external sensor devices and the specific physiological environmental conditions. consider conditions, in particular a lumen size of vessels, cavities and the like medical-biological parameters. Finally, the dimensioning of the tracking body also depends on whether it should be designed as a freely moving body or as a marking component integrated in a medical instrument.

In principle, a simultaneous use of different types of tracking bodies and a distinctive detection or a targeted response of these different types is possible by using tracking bodies 10 with base bodies 11 which have different magnetic characteristics, in particular with regard to the Show remanence and the coercive force. Magnetic materials with a coercive field strength in the range from 0.1 kA / m to 500 kA / m are considered to be particularly expedient.

This makes it possible to use the Hc switching method to activate a first type of tracking body with a finite remanence at a first coercive field strength of, for example, 500 kA / m, then to reverse the direction of the external magnetic field and to magnetize a second type a coercive field strength of 0.1 kA / m and thus to address both the first and the second type selectively, to use them as a means for drug delivery or to detect either the position of the first or the second type. In this way, a targeted influencing of a whole bandwidth can take place simultaneously in a given environment of existing tracking bodies and prepared for different tasks, whereby in principle an extensive range of types of a large number of tracking bodies can be used in parallel. The tracking bodies can thus remain on call in the operating area and can be selectively activated or deactivated if required.

Methods and devices for position detection both for freely movable implanted tracking bodies and for tracking bodies designed as components of an instrument set are described below with reference to FIGS. 2a to 5. However, a combination of the pure position detection and a trajectory tracking of the tracking body based on it with the vehicle and indicator function described above can always be carried out. A selective trajectory tracking of different types of tracking bodies is also possible using the described Hc switching processes.

FIGS. 2a to 2c show different embodiments of sensor clusters 20 which are used to determine the position and orientation of the tracking bodies 10. A sensor cluster 20 represents the smallest detector unit with which the position of the tracking body is detected. Different embodiments of the sensor cluster 20 can be used.

FIGS. 2a and 2b show flat geometries of plate-like sensor clusters 20 in a rather elongated, rectangular shape in FIG. 2a and in an essentially square embodiment in FIG. 2b. In these embodiments, the individual sensor cluster consists of a base plate 25, which is provided with a recess for fastening an interface device 21. A set of gradiometer sensors 30 is arranged on the base plate in a suitable geometric arrangement. The embodiment shown in FIG. 2a shows an essentially linear gradiometer geometry for tracking a tracking body in an elongated operating field, FIG. 2c discloses a circular gradiometer geometry for tracking a tracking body trajectory in a flat, narrowly defined operating field , which enables a high spatial and location resolution.

The geometry of the gradiometer sensors 30 responds to the magnetic field strength vector generated by the magnetic dipole field of the tracking body 10 and registers its amount and direction at the respective locations. The resulting signals are derived from the respective sensor cluster 20 and evaluated in a measuring and control device, the exact localization of the tracking body being calculated.

In addition to the planar embodiments of the sensor cluster 20 shown in FIGS. 2a and 2b, spatial measurement geometries of the gradiometer sensors 30 are also possible. 2c shows such an arrangement in an exemplary representation. In this case, the sensor cluster 20 consists of an essentially spherical arrangement of gradiometers 30, which are stabilized in a defined measurement geometry by means of holding struts 26. The embodiment shown in FIG. 2c is particularly suitable for tracking a trajectory of a tracking body in a volume area.

An inverse tracking concept is followed to determine the position of the tracking body 10. This means that from the measured field distribution using model adaptations, adaptive calculation methods and the like, the methods described below are used to determine the locations and position parameters that uniquely characterize the tracking body.

3a illustrates the parameters of the tracking body to be determined. These are, on the one hand, the position within a given coordinate system, characterized by the location coordinates X, Y, Z. Furthermore, the magnetic dipole of the tracking body takes an orientation at this point in the form of the polar angle coordinates φ and θ. Finally, the magnetic moment m of the tracking body represents a further unknown quantity. A maximum of six degrees of freedom for characterizing the tracking body can thus be determined. With a predetermined number of gradiometers 30 in a sensor cluster 20, which is generally greater than 6, there is thus the need to solve an over-determined, inverse problem. To solve the problem, adaptive gradient methods in combination with fuzzy evolution algorithms, for example the Marquardt-Levenberg method, are used, which in their entirety represent a search strategy carried out by a measuring and control unit.

The determination of the polar orientation is particularly necessary when the tracking body is designed as an integral part of an instrument, the orientation of the magnetic dipole of the tracking body correlating with the position of the corresponding component of the instrument. Such an instrument is shown schematically and by way of example in FIG. 3b. The figure shows a measuring head 51 of an endoscopic probe for examining a body cavity, for example a cardiac catheter 50 or a gastrointestinal probe. In such embodiments, the position of the measuring head is precisely determined with the aid of the methods mentioned. Using the procedures mentioned for inverse tracking and the methods described below for improved detection of the measurement signals, spatial resolutions of the spatial position of the tracking body with an accuracy of 0.5 mm and orientation detections with a resolution in the range of a few angular minutes can also be influenced by clinical contaminants, high-frequency fields in the environment and the presence of metallic but non-magnetic objects.

The sensitivity of the arrangement of the tracking body and sensor cluster can be scaled by the size of the magnetic moment of the tracking body. This is made possible in advance, for example, by choosing a suitable tracking body. Furthermore, an ongoing manipulation of the magnetic moment during tracking can be realized by an external magnetic field effect, in particular by the described Hc switching process. Electromagnetic shields can largely be dispensed with.

FIGS. 4 and 5 show exemplary applications of architectures of sensor clusters 20 in a number of advantageous embodiments. FIG. 4 shows an architecture of sensor clusters 20, which are connected to form a sensor cluster arrangement 55 and are used in this exemplary embodiment to track a trajectory of a tracking body implanted in a vascular system of an arm 35. The sensor cluster arrangement 55 is formed by a series of interconnections of the individual sensor clusters, which is indicated in FIG. 4 as thick connecting lines between the individual sensor clusters 20. The sensor cluster arrangement 55 at least partially encloses the volume of the arm 35. In this exemplary embodiment, it is placed directly on the arm like a sleeve and lies on the skin. A simpler configuration of the sensor cluster arrangement, not shown here, consists in the implementation of a more or less rigid “tunnel” from the sensor clusters 20 into which the arm is inserted. The tunnel can also be designed as part of an armrest. Each for a special application The required sensor cluster arrangement 55 is in any case assembled modularly from the sensor clusters 20. The sensor clusters 20 thus form basic “building blocks” for the construction of a detector architecture adapted for special purposes, which can be varied in any way. When the trajectory of the tracking body is traced within the vascular system of the arm 35, the sensor clusters 20 form a network that communicates with one another within the sensor cluster arrangement 55 and is controlled and monitored by a measuring and control device 40. For this purpose, the measuring and control device contains a communication protocol for the interaction of the sensor clusters 20 within the network. The interaction serves at least to self-calibrate the sensor cluster arrangement to optimize the signal-to-noise ratio of the measurement carried out. Among other things, the mutual position of the individual sensor clusters within the network of the sensor cluster arrangement 55 is first compared with one another in a predetermined laboratory coordinate system and the geometric shape of the sensor cluster network is thus recorded as a data structure. In a further exemplary functionality of the communication protocol, the sensor cluster 20 which is most favorable for tracking the trajectory is selected during the measurement and the trajectory tracking is transferred from a first to a second sensor cluster, and the network of the sensor clusters 20 is thus continuously optimized. In connection with this, operations for noise filtering and for optimizing the measuring speed are carried out. Furthermore, the measuring and control device 40 has algorithms for determining global optima for the configured configuration of the sensor cluster arrangement 55 and for error corrections. This decisively supports the metrological stability of the configuration.

The embodiment from FIG. 4 also expediently has a source for an external magnetic field for influencing the tracking body described above or an entirety of tracking bodies in the form of Hc switching or the active movement of the tracking body in the manner already described on. This is symbolically indicated in FIG. 4 by a field coil 43 with a magnetic field controller 44. It is advantageous either to design the field coil 43 to be movable along as many degrees of freedom as possible, or to replace a field coil configuration for generating magnetic fields in different configurations, for example as gradient fields or circulating fields, instead of a single field coil. 5 shows in a further exemplary embodiment an exemplary configuration of a tracking body integrated in a surgical instrument, which is arranged here in a measuring head 51 of a heart catheter 50. As in the exemplary embodiment from FIG. 4, the trajectory of the tracking body is also tracked here by a correspondingly designed sensor cluster arrangement 55. In this particular exemplary embodiment, the sensor cluster arrangement can be designed as a “tunnel” arranged around the upper body of the patient, or it can lie flat on the patient's chest. The most expedient embodiment of the sensor cluster arrangement 55 is determined in practice in each case.

In a modification of the embodiment of the sensor cluster arrangement 55 from FIG. 4, a two-part sensor cluster arrangement comprising a fixed component 56 and a variable component 57 is preferred in the embodiment shown in FIG. 5. The fixed component 56 is designed in the manner already described as a device for tracking the trajectory of the tracking body in accordance with the exemplary embodiment according to FIG. 4. The variable component 57 forms part of a superordinate arrangement 60, which surrounds the sensor cluster arrangement spatially, for executing an imaging method, in particular for a computer tomography or a magnetic resonance tomography. With such a configuration, the tracking of the cardiac catheter measuring head 51 is combined with an imaging method. The variable component 57 of the sensor cluster arrangement acts as a sample for the sensor cluster arrangement 55 itself, as well as for the imaging arrangement 60. The position of the variable component 57 is predetermined within the configuration of the sensor cluster arrangement 55 and is continuously monitored within the sensor cluster arrangement. It therefore forms a clearly defined reference point in the coordinate system of the sensor cluster arrangement 55. On the other hand, the variable component 57 of the sensor cluster arrangement clearly emerges within the encompassing imaging arrangement 60, for example as a contrast image in a computer tomography section or a magnetic resonance tomography image.

The trajectory of the measuring head 51 with the integrated tracking body of the cardiac catheter 50 is thus detected with a very high accuracy by the sensor cluster arrangement 55. The position of the tracking body itself in relation to the variable component 57 of the sensor cluster arrangement is thus also known, so that with suitable image processing means, a positional representation of the measuring head 51 in the magnetic resonance tomographic image can subsequently be made on the basis of the contrast of the variable component 57 of the sensor cluster arrangement 55 that is emerging there. This can be done, for example, by a graphically inserted icon, for example a stylized vector arrow, which shows the operator the exact orientation of the measuring head. The variable component 57 of the sensor cluster arrangement 55 thus acts as a kind of “magnifying glass” or a microscope for locally improving the image resolution of the image obtained from the magnetic resonance tomography or in another way from the arrangement 60, so that the operator actuates the cardiac catheter at the cardiac catheter control 52 in one can perform particularly precise and precise manner.

Bezugszeicheniiste

10 tracking bodies

11 base body, ferromagnetic

12 activatable section 20 sensor cluster 21 interface

25 base plate

26 struts

30 gradiometer arrangement 35 arm 36 heart

40 measuring and control device

41 Communication protocol

43 magnetic field coil

44 Magnetic field control 50 probe, cardiac catheter

51 probe head

52 Probe control

55 Sensor cluster arrangement

56 Sensor cluster arrangement, fixed component 57 Sensor cluster arrangement, variable component 60 external imaging arrangement H external magnetic field m magnetic dipole moment X, Y, Z spatial coordinates θ, φ orientation angle

Claims

claims

1. Device for localizing, influencing and guiding tracking bodies (10), comprising at least one tracking body introduced into a physiological structure and a sensor device located outside the physiological structure for determining the position of the tracking body and a measuring and control unit, characterized by - at least one tracking body as a body characterized by finite remanent magnetization with a variable magnetic dipole moment and a resulting anisotropic magnetic dipole field,

the sensor device in the form of a set of modular sensor clusters (20) sensitive to the anisotropic dipole field and covering a measurement range, each with a set of magnetic field sensors (30) integrated in the sensor cluster in a specific measurement geometry,

- The measuring and control unit (40) in metrological connection with the entirety of the sensor cluster.

2. Device according to claim 1, characterized in that the at least one tracking body (10) consists of a material with the greatest possible remanence magnetization and the lowest possible coercive field strength.

3. Device according to claim 2, characterized in that the at least one tracking body (10) made of a neodymium-iron-boron compound coated with a physiologically and magnetically neutral material

NdFeB exists.

4. Device according to one of the preceding claims, characterized in that the at least one tracking body (10) forms an integral part of a medical instrument (50), in particular a medical pointer device, an endoscope or the like, further probe device.

5. Device according to one of the preceding claims, characterized in that the at least one tracking body (10) is designed as a freely moving object circulating in an organism, in particular in body cavities.

6. The device according to claim 5, characterized in that the at least one tracking body (10) activatable and / or reactive, in particular tissue-marking or controlled substance-releasing sections (12) and / or the like applied to a given physiological environment and / or externally Influences, especially external magnetic fields (H), sensitive components.

7. The device according to claim 1, characterized in that each individual sensor cluster (20) as a minimal configuration of an entirety of gradiometers (30) for localizing the at least one tracking body, in particular for detecting a position in space (X, Y, Z) and detection of an orientation (θ, φ) is carried out.

8. Device according to one of the preceding claims, characterized in that the individual sensor cluster (20) interfaces (21) for interconnection with a

Has a total of further sensor clusters.

9. Device according to one of the preceding claims, characterized in that the sensor cluster (20) is designed as part of a test person's position, in particular as part of headrests, arm and / or backrests, table tops and the like devices.

10. Device according to one of the preceding claims, characterized in that a whole of interconnected sensor clusters (20) forms a sensor cluster arrangement (55), the sensor cluster arrangement covering an expedient area of an examination field.

11. Device according to one of the preceding claims, characterized in that the entirety of the sensor clusters has a fixed portion (56) and a variable, in particular position-changing portion (57), the variable portion as a component for position marking in an external imaging arrangement ( 60), in particular a magnetic resonance tomography or computer tomography device.

12. A method for localizing and influencing at least one tracking body (10) introduced into a physiological environment, characterized in that

- With the aid of an arrangement of at least one set of magnetic field sensors (30) combined in a sensor cluster (20) from a measured one

Distribution of a field strength and field direction of the at least one tracking body (10) surrounded by a magnetic dipole field, its position in space (X, Y, Z) and its orientation (θ, φ) and / or its trajectory is determined and / or - optionally physical / chemical properties and / or a trajectory of the at least one tracking body can be specifically changed by an externally acting magnetic field (H) and / or physiological processes in the surroundings of the at least one tracking body.

13. The method according to claim 12, characterized in that the tracking body (10) is designed as a position reference point of a diagnostic probe and / or pointer device, in particular a catheter or an endoscopic device, wherein

- A movement, a current position in space (X, Y, Z) and a current orientation (θ, φ) of the position reference point is continuously determined by the sensor cluster arrangement (55).

14. The method according to claim 12, characterized in that the tracking body (10) is implanted as a freely movable indicator in the relevant physiological environment, in particular as a diagnostically active component of a suspension, wherein - a movement, a current position in space (X, Y, Z) and a current one

Orientation (θ, φ) of the indicator is continuously determined by the sensor cluster arrangement (55).

15. The method according to any one of claims 12 to 14, characterized in that the position determination of the tracking body (10) from measurement data on an amount and a direction of a vector of a magnetic field strength determined in each individual magnetic field sensor (30) of the sensor cluster (20) of the magnetic field generated by the tracking body, wherein - form output data for an algorithm stored in a position determining device for a search strategy for localizing the tracking body.

16. The method according to claim 15, characterized in that the algorithm of the search strategy executes methods for inverse tracking, in particular adaptive gradient methods in combination with a fuzzy evolution algorithm.

17. The method according to any one of the preceding claims, characterized in that when using multiple sensor clusters (20) by means of an internal ■ communication protocol (41) between the sensor clusters a dynamic

Integration of the sensor clusters in the sensor cluster arrangement (55) is carried out, wherein

- In particular, an optimization of a signal-to-noise ratio in the entire sensor cluster arrangement and an optimization of the amount of data generated by the sensor cluster arrangement are carried out.

18. The method according to any one of the preceding claims, characterized in that the magnetic moment (m) of the at least one tracking body (10) is influenced by means of an externally supplied magnetic field (H), the latter

Magnetization is changed, in particular deleted or generated.

19. The method according to any one of the preceding claims, characterized in that by means of an externally supplied magnetic field with a corresponding

In the direction-oriented field vectors, an active displacement of the at least one implanted freely movable tracking body (10) is generated.

20. The method according to any one of the preceding claims, characterized in that a controlled release of substances bound on the surface of the tracking body is generated by means of the changed magnetization of the at least one tracking body (10).

1. The method according to any one of the preceding claims, characterized in that the position of a variable, in particular position-changing, an extended device associated component (57) of the sensor cluster arrangement (55) by a fixed component (56) of the sensor cluster arrangement is detected and / or the variable component the sensor cluster arrangement is used as a location marker in the expanded imaging arrangement, the position in space (X, Y, Z) and the orientation (θ, φ) of the tracking body determined by means of the sensor cluster arrangement being inserted into the generated image.