Tracking method, hybrid medical tracking system, and medical diagnostic and / or therapy device

Abstract

The invention includes a method for medically tracking an object inserted into a patient's body by means of a hybrid medical tracking system with an electromagnetic tracking system and an optical tracking system, comprising the following steps: capturing and evaluating measurements of at least one optical sensor of the optical tracking system, wherein a position and / or orientation of a field generator configured to generate an electromagnetic field of the electromagnetic tracking system in a first coordinate system is determined; capturing and evaluating measurements of at least one electromagnetic sensor of the electromagnetic tracking system, wherein a position and / or orientation of the object in a second coordinate system is determined; transforming the determined position and / or orientation of the object from the second coordinate system into the first coordinate system; and outputting the result.

Description

[0001] The invention relates to a method for medically tracking an object introduced into a patient's body according to patent claim 1, a hybrid medical tracking system according to patent claim 6 and a medical diagnostic and / or therapeutic device with a hybrid tracking system according to patent claim 10.

[0002] In modern medicine, tracking systems are used to navigate objects on or in a patient's body in order to determine the position and orientation of the object. In this context, various techniques are known for carrying out this type of tracking. For example, optical tracking systems with stereo cameras (e.g. infrared) and corresponding markers can be used to track objects outside the body. However, this is not possible for objects inside the body because a line of sight is required. In particular, this is not possible for monitoring during an interventional procedure involving navigation of an object or instrument inside the patient's body. In such a case, the camera must be attached to the object and inserted into the patient, or X-rays must be used, for example, to take a fluoroscopic image.X-rays, on the other hand, have the disadvantage of exposing the patient to radiation, so they should be used sparingly. For objects inside the body, for example, electromagnetic tracking can be used. Electromagnetic tracking has the disadvantage that it can only monitor a small volume and that, for example, moving metal parts in the field of the field generator can severely interfere with the measurement.

[0003] It is an object of the present invention to provide a method that enables an improvement in the range of a conventional medical method for tracking an object in a patient's body; furthermore, it is an object of the invention to provide a medical tracking system and a medical diagnostic and / or therapeutic device for carrying out the method.

[0004] The object is achieved according to the invention by a method for medically tracking an object introduced into a patient's body according to patent claim 1, a hybrid medical tracking system according to patent claim 6 and a medical diagnostic and / or therapeutic device with a hybrid tracking system according to patent claim 10. Advantageous embodiments of the invention are each the subject of the associated subclaims.

[0005] The invention comprises a method for medically tracking an object introduced into a patient's body by means of a hybrid medical tracking system with an electromagnetic tracking system and an optical tracking system, comprising the following steps: recording and evaluating measurements from at least one optical sensor of the optical tracking system, wherein a position and / or orientation of a field generator of the electromagnetic tracking system, designed to generate an electromagnetic field, is determined in a first coordinate system; recording and evaluating measurements from at least one electromagnetic sensor of the electromagnetic tracking system, wherein a position and / or orientation of the object is determined in a second coordinate system; transforming the determined position and / or orientation of the object from the second coordinate system to the first coordinate system; and outputting the result.

[0006] The method combines the advantages of two different tracking systems without having to accept their disadvantages by advantageously connecting an electromagnetic tracking system and an optical tracking system in series. This method allows for the precise detection of an object inside a patient (electromagnetic tracking) while simultaneously extending the limited range of a pure EM tracking system through optical tracking of a component of the electromagnetic tracking system. The hybrid tracking system also eliminates potentially harmful X-ray radiation. The method can be performed and used quickly and easily.

[0007] The invention also comprises a hybrid medical tracking system with at least two tracking systems for tracking an object introduced into a patient's body, comprising an electromagnetic tracking system with a field generator, an EM evaluation unit and at least one electromagnetic sensor for detecting a position and / or orientation of an object in a second coordinate system, an optical tracking system with at least one optical sensor and an evaluation unit, which is designed to determine the position and / or orientation of the field generator of the electromagnetic tracking system in a first coordinate system, a transformation unit for transforming the position and / or orientation of the object from the second coordinate system into the first coordinate system, and a system controller for controlling the hybrid medical tracking system.Such a hybrid tracking system can precisely detect an object inside a patient while simultaneously extending the limited range of a pure EM tracking system. It can be installed and deployed quickly and easily.

[0008] According to one embodiment of the invention, the electromagnetic tracking system comprises at least three electromagnetic sensors that can be inserted into the body, in particular three coils arranged orthogonally to each other to cover all three spatial directions. The coils can be arranged, for example, on the object to be detected (e.g., a catheter). Transponders or other electromagnetic sensors can also be present.

[0009] The general principle of an electromagnetic tracking system is as follows: the field generator of the electromagnetic tracking system emits an oscillating high-frequency field, and the sensors then respond to the field. The three coils convert the high-frequency field into a voltage signal (see the law of induction). The voltage signal can be measured and processed based on parameters such as amplitude, phase, and frequency. The position and orientation of the sensor can then be determined through triangulation, and the coils can then be used to calculate the 3D position and orientation.

[0010] According to a further embodiment of the invention, the optical sensor is formed by at least one camera, in particular a stereo camera operating in the infrared range, which is arranged in an examination room, and optical markers are arranged on the field generator. Multiple stereo cameras can also be installed at different locations in the examination room in order to cover the largest possible examination area. It is important that the examination area to be covered requires a direct line of sight to at least one stereo camera. The stereo camera operates in the infrared range and outputs, for example, 6-DoF position data of the corresponding markers arranged on the field generator. Examples of such optical tracking systems include the Polaris® system from NDI (https: / / www.ndigital.com / optical-navigation-technology / polaris-vega / ).

[0011] According to a further embodiment of the invention, the field generator is arranged on an adjustable, automatically controllable holder and can be moved automatically and / or manually by means of this. An automatic control system can be provided for this purpose. The holder can be formed, for example, by a robotic arm or a C-arm. The holder can be attached to a mobile equipment cart, another medical device or a patient bed. Advantageously, when the sensors move, the field generator tracks the object by adjusting the holder. This can be carried out, for example, in such a way that movement always occurs as soon as the sensors move away from the detectable area. Tracking can also occur based on navigation planning data, based on X-ray images or based on movement of the patient or patient bed.This ensures reliable and precise tracking of the object at all times. The field generator can also be designed to be mobile or portable and moved manually, for example. The mobile field generator can be placed on the patient or another surface, for example. The field generator can be powered by a (rechargeable or replaceable) battery, for example.

[0012] According to a further embodiment of the invention, the optical sensor is registered to a monitoring volume before the start of the method. This can be, for example, a planning volume for an interventional procedure (e.g., with robot-controlled navigation of a catheter in a patient's cavity) or an examination area of ​​a medical diagnostic and / or therapeutic device such as an X-ray machine or magnetic resonance imaging device. In this way, the determined position and / or orientation of the object can be easily displayed in the planning image or current X-ray image, for example, by means of superimposition.

[0013] According to a further embodiment of the invention, the position and / or orientation of the object is displayed on a display unit, for example a monitor or a touchscreen, or stored in a memory or a database for later use.

[0014] The invention further comprises a medical diagnostic and / or therapeutic device comprising a hybrid tracking system as described above. This can additionally comprise an X-ray device with an X-ray source and an X-ray detector, designed to acquire X-ray images of the patient. In this way, X-ray images, e.g., fluoroscopic images, can be acquired at specific times in addition to monitoring. For automatic control of the object (e.g., catheter), the medical diagnostic and / or therapeutic device expediently comprises a robotic control system with a drive device and a control unit for moving and controlling the robotically controllable object through a hollow organ of the patient.

[0015] The invention and further advantageous embodiments according to the features of the dependent claims are explained in more detail below with reference to schematically illustrated embodiments in the drawings, without thereby limiting the invention to these embodiments. They show: Fig. 1 Steps of a method according to the invention for medically tracking an object introduced into a patient's body; Fig. 2 a view of a hybrid medical tracking system; Fig. 2 a view of a medical diagnostic and / or therapeutic device with a hybrid medical tracking system; and Fig. 4 another view of a hybrid medical tracking system with an adjustable mount of the field generator.

[0016] In the Fig. 2 (and the Fig. 4) shows a hybrid medical tracking system with an electromagnetic tracking system and an optical tracking system. Both tracking systems are advantageously interconnected to increase the effective range, which individual tracking systems cannot achieve, and simultaneously utilize the advantages of both tracking systems. The optical tracking system has at least one stereo camera 24 for measuring in 6 degrees of freedom, which is arranged, for example, permanently installed in an examination room, and an evaluation unit 26, which evaluates the measurements of the stereo cameras. The electromagnetic tracking system has a field generator 22 for generating a high-frequency field, an EM evaluation unit 25 (e.g., data processing unit), and at least one, optimally three electromagnetic sensors, e.g., in the form of three coils 23 or transponders. The three coils 23 are, for example,They are arranged orthogonally to one another and can be arranged on the object to be monitored, e.g., a catheter 21, or arranged in some other way near the object to be monitored. Optical markers (e.g., infrared markers) are arranged on the field generator, which can be detected by the stereo camera 24. The field generator 22 can, for example, be mobile and can be moved manually or automatically.

[0017] The object, e.g., the catheter 21, is located, for example, in a hollow organ, an organ, or a body part of the patient 20, e.g., during a surgery or an interventional medical procedure (navigation, stent placement, ablation, etc.). The hybrid medical tracking system is controlled, for example, by a system controller 27; a transformation unit 32 is also present.

[0018] The field generator 22, for example, emits an (oscillating) high-frequency field to which the electromagnetic sensors respond. The electromagnetic sensors convert the high-frequency field into a voltage signal (law of induction). The voltage signal can be measured and processed based on parameters such as amplitude, phase, and frequency. Triangulation can then be used to determine the position and orientation of the sensor, and thus calculate the 3D position and orientation of the object. Electromagnetic tracking systems, for example, based on magnetic positioning or transponder localization, are known from the state of the art (e.g., article "Wireless electromagnetic tracking in medicine," AM Franz et al., Image processing for medicine 2014, Informatik aktuell, 2014).

[0019] Before starting the procedure, the optical tracking system (or the first coordinate system associated with it) is registered or calibrated to a reconstructed 3D volume of the patient, e.g. to a preoperative X-ray image, or to another associated medical diagnostic and / or therapeutic device (e.g. X-ray device, MR, CT, ultrasound device).

[0020] In the Fig. 1 shows steps of a method for medically tracking an object inserted into a patient's body using the hybrid medical tracking system. In a first step 10, measurements are recorded by the at least one stereo camera 24 in a first coordinate system and evaluated by an evaluation unit 26. The evaluation is particularly directed at detecting or determining the position and / or orientation of the field generator 22 of the electromagnetic tracking system. This is achieved, for example, by the stereo camera emitting infrared light, which is reflected by the optical markers arranged on the field generator 22. The position and / or orientation of the field generator 22 is then calculated by triangulation. The first coordinate system is the coordinate system of the optical tracking system.

[0021] In a second step 11, the activated electromagnetic tracking system performs at least one measurement and associated evaluation to determine the position and / or orientation of the object in a second coordinate system. The second coordinate system is the coordinate system of the electromagnetic tracking system, so that the determined position and / or orientation of the object is applied in this second coordinate system. In order to obtain the position and / or orientation of the object, e.g. in relation to the preoperative image / X-ray image or the patient, a transformation of the determined position and / or orientation of the object from the second coordinate system to the first coordinate system is carried out in a third step 12. This can be carried out by a transformation unit 32, e.g. representing a separate unit or being generated by software located on a PC.The system controller 27 and the transformation unit can also be formed by a common device with different algorithms or control programs. In a fourth step 13, the result is then output, for example, to a monitor, another display unit, or stored in a memory or database. The entire process is controlled by the system controller 27, for example, automatically or triggered by an operator input.

[0022] The measurements of the electromagnetic tracking system, the detection of the field generator by the optical tracking system, and the coordinate transformation and output can be repeated continuously, e.g., until a termination criterion is met, until the end of the procedure, or until an operator input is received. This allows for precise and comprehensive tracking of the object during a procedure or surgery.

[0023] In the Fig. 4 shows a medical hybrid tracking system in which the field generator 22 is arranged on an adjustable, automatically controllable holder 33 and can be moved automatically and / or manually by means of this. An automatic control can be provided for this purpose, for example also the system controller 27. The holder 33 can be formed, for example, by a robotic arm or a C-arm. The holder can be attached to a mobile equipment cart, another medical device, or the patient bed 31. Alternatively, a rail or other mechanical construction can also be provided. The field generator 22 can, for example, track the object by adjusting the holder 33 when the sensors move (e.g. when these are arranged on the moving object). This can be carried out, for example, in such a way that a movement is always triggered as soon as the electromagnetic sensors (coils, transponders, etc.)) move out of the detectable range of the field generator 22. Tracking can also be performed based on navigation planning data, X-ray images, or movement of the patient or patient bed. This ensures reliable and precise tracking of the object at all times.

[0024] In the Fig.3 shows a medical diagnostic and / or therapeutic device with a hybrid tracking system and an X-ray device 28 associated therewith. The X-ray device 28 has, for example, a C-arm with an X-ray source and an X-ray detector and is designed to acquire X-ray image data of an organ or body part of the patient 20. The C-arm is adjustable so that projection image data can be acquired from different projection directions. The X-ray device 28 is controlled, for example, also by the system controller 27. The X-ray device 28 can be a fixed or mobile X-ray device, for example a cone beam CT, an angiography X-ray device, a CT, or a mobile C-arm X-ray device. The patient is generally arranged on a patient table 31.Generally, the medical diagnostic and / or therapeutic device also includes at least one memory unit, a display unit, and an input unit (not shown). Additionally, a robotic control system with a drive device 29 and a control unit 30 for moving and controlling the robotically controllable object, e.g., catheter 21, through, for example, a hollow organ of the patient 20 may also be present. This system can, for example, exchange data with the hybrid tracking system to achieve improved tracking.

[0025] The electromagnetic sensors (coils, transponders, etc.) can be arranged on the object or inserted independently into the patient's body, e.g., into the tissue of an organ. The electromagnetic tracking system can be used to locate and track inserted objects such as catheters or other instruments.

[0026] As soon as the field generator enters the optical measurement field of the optical tracking system, the hybrid tracking system begins evaluating the measurements of the electromagnetic tracking system, and the data can be transformed from the second coordinate system of the field generator to the first coordinate system. Since the measurement volume of the electromagnetic tracking system is small and the best electromagnetic tracking results are only achieved in certain regions of the measurement field, this can be used to specifically determine how the field generator must be moved to achieve optimal measurement results. Furthermore, controlled assistance systems can be used to automatically position the field generator. This extends the limitations of electromagnetic tracking to the size of the measurement volume of the optical tracking system.

[0027] Regardless of the grammatical gender of a particular term, persons with male, female or other gender identities are included.

[0028] The invention can be briefly summarized as follows: For a particularly precise detection of an object inside a patient over a large range, e.g. during an interventional medical procedure, a method for medically tracking an object introduced into a patient's body by means of a hybrid medical tracking system with an electromagnetic tracking system and an optical tracking system is provided, comprising the following steps: Recording and evaluating measurements of at least one optical sensor of the optical tracking system, wherein a position and / or orientation of a field generator of the electromagnetic tracking system, which field generator is designed to generate an electromagnetic field, is determined in a first coordinate system, Recording and evaluating measurements of at least one electromagnetic sensor of the electromagnetic tracking system,wherein a position and / or orientation of the object is determined in a second coordinate system, transformation of the determined position and / or orientation of the object from the second coordinate system into the first coordinate system, and output of the result., QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited non-patent literature

[0000] Polaris ® system from NDI (https: / / www.ndigital.com / optical-navigation-technology / polaris-vega /

[0010] Wireless electromagnetic tracking in medicine”, AM Franz et al., Image processing for medicine 2014, Informatik aktuell, 2014

[0018]

Claims

[1] Method for medically tracking an object introduced into a body of a patient (20) by means of a hybrid medical tracking system with an electromagnetic tracking system (22; 23; 25) and an optical tracking system (24; 26) with the following steps: • Recording and evaluating measurements of at least one optical sensor of the optical tracking system (24; 26), wherein a position and / or orientation of a field generator (22) of the electromagnetic tracking system (22; 23; 25) designed to generate an electromagnetic field is determined in a first coordinate system, • Recording and evaluating measurements of at least one electromagnetic sensor of the electromagnetic tracking system (22; 23; 25), whereby a position and / or orientation of the object in a second coordinate system is determined, • Transformation of the determined position and / or orientation of the object from the second coordinate system to the first coordinate system, and • Output of the result. [2] Method according to claim 1, wherein an adjustable holder (33) on which the field generator (22) is arranged is controlled to move the field generator (22). [3] Method according to one of the preceding claims, wherein the optical sensor is registered to a monitoring volume before the start of the method. [4] Method according to one of the preceding claims, wherein the position and / or orientation of the object is displayed on a display unit or stored in a memory. [5] Method according to claim 2, wherein the electromagnetic sensor(s) are arranged on the object and the field generator (22) is guided to the object upon movement of the electromagnetic sensors. [6] Hybrid medical tracking system with at least two tracking systems for carrying out a method according to one of claims 1 to 5, comprising • an electromagnetic tracking system (22; 23; 25) with a field generator (22), an EM evaluation unit (25) and at least one electromagnetic sensor for detecting a position and / or orientation of an object in a second coordinate system, • an optical tracking system (24; 26) with at least one optical sensor and an evaluation unit, which is designed to detect the position and / or orientation of the field generator (22) of the electromagnetic (22; 23; 25) tracking system in a first coordinate system, • a transformation unit (32) for transforming the position and / or orientation of the object from the second coordinate system into the first coordinate system, and • a system controller (27) for controlling the hybrid medical tracking system. [7] Hybrid tracking system according to claim 6, wherein the electromagnetic tracking system (22; 23; 25) has at least three electromagnetic sensors which can be introduced into the body, in particular three coils (23) arranged orthogonally to one another. [8] Hybrid tracking system according to one of claims 6 or 7, wherein the optical sensor is formed by at least one camera (24), in particular a stereo camera operating in the infrared range, which is arranged in an examination room and wherein optical markers are arranged on the field generator. [9] Hybrid tracking system according to one of claims 6 to 8, wherein the field generator (22) is arranged on an adjustable, automatically controllable holder (33) and is movable by means of this. [10] Medical diagnostic and / or therapeutic device comprising a hybrid medical tracking system according to one of claims 6 to 9. [11] Medical diagnostic and / or therapeutic device according to claim 10, comprising an X-ray device (28) with an X-ray source and an X-ray detector, designed to take X-ray images of the patient. [12] Medical diagnostic and / or therapeutic device according to claim 10, comprising a robotic control system (29; 30) with a drive device (29) and a control unit (30) for moving and controlling a robotically controllable object through a hollow organ of the patient (20).

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