DE202022104403U1 - Device for controlling the movement of a medical device in a magnetic field - Google Patents

Abstract

A device configured to perform a method of controlling movement of a medical device in a magnetic field, the medical device comprising a coil set, the method comprising:
- determining a torque that must be applied to the medical device in order for the medical device to perform the movement,
- determining a minimum current that must be supplied to each coil of the coil set in order to obtain the determined torque by solving an optimization problem, and
- Supply each coil of the coil set with the specified minimum current so that the medical device performs the movement.

Description

TECHNICAL AREA

The present disclosure relates to a device, optionally a computing device, configured to perform a method of controlling movement of a medical device in a magnetic field.

Additionally or alternatively, the present disclosure may relate to a medical device configured to be controlled by the method.

Additionally or alternatively, a computer program may be provided, the computer program comprising instructions which, when the program is downloaded from a computer, e.g. B. the data processing device, cause the computer to carry out the method at least partially.

Additionally or alternatively, a computer-readable (storage) medium can be provided, the computer-readable medium containing instructions which, when executed by a computer, cause the computer to at least partially carry out the method.

BACKGROUND

The discussion of related art in the specification is in no way to be construed as an admission that such related art is common knowledge or common knowledge in the field.

The widespread use of non-invasive medical imaging modalities in surgery such as magnetic resonance imaging (MRI), X-ray and ultrasound (US) has enabled the use of micrometer-sized surgical instruments such as guidewires and catheters in tight cavities in the body. The traditional method, known as the Seldinger technique, involves accessing a blood vessel with a puncture needle, a steerable guidewire passed through the needle, and a preformed or steerable catheter passed over the guidewire.

However, various problems can arise with this method, such as: B. Vessel perforation, breakage of the device tip, kinking, loop formation or loss of the guide wire.

Guidewires and catheters can also lose manual torque transmission to the distal tip in tortuous vessels, making navigation difficult, especially when narrow vessels are at small angles.

Steerable (active) catheters and continuum robots offer an alternative to traditional passive guidewire-based catheter delivery methods, allowing for better maneuverability and remote control.

The main challenge in active catheter design is the transmission of force and torque through the soft, slender body to actuate the catheter tip. Some systems use power transmission via tendons. However, researchers have proposed many alternative propulsion mechanisms, such as B. Multi-backbone, concentric tubes, pneumatics, smart materials, hydraulics, magnetics or hybrid approaches to overcome certain disadvantages of tendon-based systems.

Integration with existing medical imaging modalities is another important part of device development. X-ray imaging is currently the gold standard for real-time visualization in minimally invasive procedures. Radiopaque catheters can be easily visualized in vascular structures filled with contrast media. However, due to the low soft-tissue contrast, it is difficult to visualize the effects of the procedure on the soft-tissue with X-ray images. Therefore, there is a growing interest in MRI-guided minimally invasive procedures, as the high soft-tissue contrast of MRI images makes the blood vessels (e.g. in a human's brain) and tissue reaction visible, there is no ionizing radiation, the tool can be tracked in real-time and physiological measurements are possible (e.g. MRI thermometry, diffusion and perfusion).

However, MRI scanners place new demands on the design and operation of medical devices. First, the permanent high magnetic field limits the choice of materials for device construction to non-magnetic materials to avoid unintended magnetic forces and torques. Second, large non-magnetic metal objects cause susceptibility artifacts in imaging. Third, the radio frequency pulses from the MRI scanner can cause the conductive materials in medical devices to heat up.

Therefore, there are numerous studies to develop MR-compatible driving techniques for the control of a device. These approaches include the use of smart materials, hydraulic, pneumatic and MRT controlled (magnetic) drive technologies.

Thermal actuation uses electricity to generate force and movement, using thermally active materials that are highly sensitive to temperature changes, such as carbon dioxide. B. Shape memory alloys (SMA).

SMAs can perform large deformations in small sizes for catheter steering. However, they generally require longer response times, exhibit highly nonlinear behavior, and can pose safety hazards by heating adjacent tissue.

Hydraulic actuation can transmit large forces through the slim catheter using fluid pressure. However, this fluid pressure across compliant continuum bodies causes radial expansion at positive pressure and buckling at negative pressure, leading to variations in soft body strength and fatigue.

MRI-guided actuation offers significant advantages over the above techniques due to its scalability, safety, response time (near instantaneous), accuracy (other methods introduce non-linearities in actuation), and degrees of freedom (DoF). In addition, MRI-guided actuators can use imaging gradient coils controlled by the user to generate spatial field gradients to control a wireless robot or magnetic catheter tip in 3D.

However, the embedding of magnetic elements in gradient control catheters results in significant distortion of the MR image as well as additional weight and bulk of the catheter.

Another MRI-guided approach is to attach microcoils to the tip of the catheter to steer the catheter using Lorentz forces through manually wound or laser-edited microcoils.

The steering based on the Lorentz force places less stress on the soft body due to the high force-to-weight ratio compared to gradient steering.

In addition, image distortion can be controlled since image artifacts only appear when the coils are activated.

Magnet assisted catheterization with microcoils has been shown to be faster than manual navigation with MR image guidance for larger angles and comparable to X-ray guidance.

However, the Joule heating effects based on micro-coils are a major problem in development. Previous research has shown that thermal tissue damage occurs above local temperatures of 44°C. Studies on catheter-integrated microcoils have shown that the use of input currents in excess of 300 mA (1.2 W) can result in vascular thrombosis, vacuolation, and medial hemorrhage. Possible solutions include the integration of heat dissipation mechanisms such as alumina at the catheter tip and passage of saline through the microcoil tip, or regulation of current to less than 300mA (1.2W) with activation times of less than 1 minute.

However, such solutions add weight and bulk to the catheter tip, require flow through the catheter, limit the size of the working channel, and limit the time required for active control in the working space.

The above description can be applied mutatis mutandis to endoscopes such as neuroendoscopes. Neuroendoscopy is a minimally invasive technique used to visualize and treat areas of the central nervous system including the skull, brain, and spine. Currently, neuroendoscopic systems are used to treat many different cases, including intraventricular lesions, craniosynostosis, spinal lesions, and skull base tumors. For this purpose, both rigid and flexible endoscopes are used in surgical procedures.

However, the standard rigid endoscopic instruments have disadvantages such as a limited field of view and the risk of trauma from blunt force. Neuronavigation can improve existing techniques, especially in patients with intraventricular pathologies. In addition, flexible endoscopes have a greater range of motion, which can be crucial in complex anatomies such as the ventricles.

Although the introduction of neuroendoscopy in surgical procedures has brought significant improvements compared to other traditionally invasive surgical procedures, there is still room for improvement such as: B. more precision and less trauma to the surrounding tissue.

It may be an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art and/or to provide a useful alternative.

SUMMARY

An apparatus configured to perform a first method of controlling movement of a medical device in a magnetic field is provided. The medical device includes a coil set.

The first method includes determining a torque that must be applied to the medical device in order for the medical device to perform the movement.

The first method includes determining a minimum current that must be supplied to each coil of the coil set to achieve the determined torque by solving an optimization problem.

The first method includes supplying the determined minimum current to each coil of the coil set so that the medical device performs the movement.

wobei:

• - I einen Strom darstellen kann, der jeweils jeder Spule des Spulensatzes zugeführt wird,
• - τ_coils ein Gesamtdrehmoment darstellen kann, das von dem Spulensatz erzeugt wird, wenn er mit dem Strom I versorgt wird,
• - τ_des das Drehmoment darstellen kann, das auf die medizinische Vorrichtung aufgebracht werden muss, damit die medizinische Vorrichtung die Bewegung ausführt, und
• - R einen Widerstand jeder Spule des Spulensatzes darstellen kann.

The optimization problem (to determine the minimum current) can be defined as follows: $$\text{I}*=\underset{\text{I}}{\text{argmin}}{\Vert {\tau }_{\text{coils}}-{\tau }_{\text{of}}\Vert }^2+a{\Vert \text{I}\Vert }_{\text{<figure-callout id="2" label="R" filenames="DE202022104403U1\_0019.png,DE202022104403U1\_0021.png" state="{{state}}">R</figure-callout>}}^2$$

whereby:

• - I can represent a current fed to each coil of the coil set,
• - τ _coils can represent a total torque generated by the coil set when supplied with the current I,
• - τ _des may represent the torque that must be applied to the medical device in order for the medical device to perform the movement, and
• - R can represent a resistance of each coil of the coil set.

Determining the torque may include solving another optimization problem to minimize the torque to be applied to the medical device such that the medical device performs the movement.

The medical device may include a flexible, generally rod-shaped portion. Additionally or alternatively, the movement can include a deformation of the rod-shaped section, which leads to a movement of a tip of the rod-shaped section.

Solving the further optimization problem may include determining the deformation of the rod-shaped section required for moving the tip of the rod-shaped section from an actual position to a desired position such that a torque required for the deformation of the rod-shaped section is is minimized. Additionally or alternatively, solving the further optimization problem may include determining the torque that needs to be applied to the medical device in order for the medical device to perform the movement that corresponds to the torque that is required to deform the rod-shaped section.

The deformation required to move the tip of the rod-shaped section from the actual position to the desired position can be determined using a model, optionally a Cosserat model, representing the non-linear dynamics of the rod-shaped section.

Additionally or alternatively, a device for performing a second method for controlling a movement of a medical device in a magnetic field can be provided. The medical device includes a coil set. The above description of the first method also applies to the second method and vice versa.

The second method includes determining a torque that must be applied to the medical device in order for the medical device to perform the movement. Determining the torque to be applied to the medical device includes solving an optimization problem to minimize the torque to be applied to the medical device so that the medical device performs the movement.

The second method involves determining the current that must be supplied to the coil set to achieve the determined torque.

The second method includes energizing the coil set with the determined current so that the medical device performs the movement.

The medical device may include a flexible, generally rod-shaped portion. Additionally or alternatively, the movement can be a deformation of the rod-shaped section include, which leads to a movement of a tip of the rod-shaped portion.

Solving the optimization problem (to minimize torque) may involve determining the deformation of the rod-shaped section required to move the tip of the rod-shaped section from an actual position to a desired position such that a torque required to deform the rod-shaped section is required is minimized. Additionally or alternatively, solving the optimization problem (to minimize torque) may include determining the torque that needs to be applied to the medical device in order for the medical device to perform the movement that corresponds to the torque required to deform the rod-shaped portion is.

The deformation required to move the tip of the rod-shaped section from the actual position to the desired position can be determined using a model, optionally a Cosserat model, representing the non-linear dynamics of the rod-shaped section.

At least one of the methods described above may include receiving user input related to the movement via a user interface, optionally including a joystick. The user interface can be direct or indirect, e.g. B. via a control unit to be connected to the medical device.

At least one of the methods described above may include determining an actual position of the medical device, optionally the tip thereof, using medical imaging. Additionally or alternatively, at least one of the methods described above may include automatic control of the movement based on the determined current position.

At least one of the methods described above may include displaying an actual position of the medical device, optionally a tip thereof, and/or a position of the medical device, optionally a tip thereof, after performing the movement on a display device. The display device can be connected to a medical imaging device.

At least one of the methods described above may include displaying on the display device the actual position of the medical device and/or the position of the medical device after performing the movement with respect to a tissue, optionally a human or an animal.

In at least one of the methods described above, the magnetic field can be generated by a medical imaging device, optionally a magnetic resonance imaging device.

In at least one of the methods described above, the magnetic field may be a static magnetic field.

In at least one of the methods described above, the medical device may comprise a catheter, optionally an endovascular catheter.

The catheter may have a tip that optionally includes a working channel that extends through the tip of the catheter. Additionally or alternatively, the catheter may include the coil set surrounding the tip. Additionally or alternatively, the catheter may include power lines arranged to provide electrical energy to the coil set.

The coil set may comprise four lateral coils arranged around the tip such that a straight line orthogonal to the longitudinal direction of the tip intersects a center point of the respective lateral coil, i. H. the four side coils are arranged around the tip such that a magnetic flux direction of the four side coils points to a center line of the tip.

A first and a second of the side coils can be connected in series. Additionally or alternatively, a third and a fourth of the lateral coils can be connected in series. Additionally or alternatively, the first and second of the side coils may be located on opposite sides of the tip. Additionally or alternatively, the third and fourth side coils may be located on opposite sides of the tip and between the first and second side coils.

The number of turns of at least one of the four lateral coils may be between 2 and 40 (i.e. 2 and 40 inclusive). Optionally, the number of turns of at least one of the four side coils may be between 4 and 30 (i.e., 4 and 30 inclusive). Optionally, the number of turns can be at least one of the four lateral coils 7 .

The coil set may include at least one axial coil arranged around the tip such that a straight line parallel to the longitudinal runs direction of the tip, a center point of at least one axial coil crosses or intersects.

At least one of the coils of the coil set can be wound by laser machining, laser lithography and/or by hand.

At least one of the coils of the coil set can have an, optionally rectangular, Archimedean spiral shape.

At least one of the coils of the coil set may have an in-plane shape.

The four lateral coils can be arranged on the same, optionally flexible, printed circuit board.

Additionally or alternatively, in at least one of the methods described above, the medical device can comprise an endoscope, optionally a neuroendoscope.

The endoscope can have a tip that optionally includes a working channel that extends through the tip of the endoscope. Additionally or alternatively, the endoscope may include the coil set surrounding the tip. Additionally or alternatively, the endoscope may include power lines arranged to provide electrical power to the coil set.

The coil set may include four lateral coils arranged around the tip such that a straight line orthogonal to the longitudinal direction of the tip intersects a center point of the respective lateral coil.

A first and a second of the side coils can be connected in series. Additionally or alternatively, a third and a fourth of the lateral coils can be connected in series. Additionally or alternatively, the first and second of the side coils may be located on opposite sides of the tip. Additionally or alternatively, the third and fourth side coils may be located on opposite sides of the tip and between the first and second side coils.

The number of turns of at least one of the four lateral coils may be between 2 and 40 (i.e. 2 and 40 inclusive). Optionally, the number of turns of at least one of the four side coils may be between 4 and 30 (i.e., 4 and 30 inclusive). Optionally, the number of turns can be at least one of the four lateral coils 7 .

The coil set may include at least one axial coil arranged around the tip such that a straight line parallel to the longitudinal direction of the tip intersects a midpoint of the at least one axial coil.

At least one of the coils of the coil set can be manufactured by laser machining, laser lithography and/or manual winding.

At least one of the coils of the coil set can have an, optionally rectangular, Archimedean spiral shape.

At least one of the coils of the coil set may have an in-plane shape.

The four lateral coils can be arranged on the same, optionally flexible, printed circuit board.

The endoscope may include an end effector connected to the tip of the endoscope.

The end effector can include a further set of coils for actuating the end effector.

The method may include actuating the end effector by applying a current to the further set of coils.

The end effector may include a gripper having two jaws pivotally connected together. Additionally or alternatively, the additional coil set can include at least one lateral coil, which is arranged on one of the two jaws.

Actuation of the end effector may include opening and/or closing the jaws of the gripper by applying current to the further set of coils. The opening may be a movement in which the jaws of the gripper are moved away from each other by being pivoted about the pivotal connection, and the closing may be a movement in which the jaws of the gripper are moved towards each other by being rotated about the swivel connection can be rotated.

The method may include ablating and/or killing tissue, optionally comprising tumor cells, using Joule heating caused by current supplied to the further set of coils for actuating the end effector, optionally opening and closing the gripper .

The tip of the endoscope can include a camera. Additionally or alternatively, the tip of the endoscope can have an illumination device, which optionally includes a light-emitting diode (LED). Additionally or alternatively, the tip of the endoscope can have an opening of a flushing channel that extends through the endoscope.

Additionally or alternatively, the disclosure is directed to the use of a grasper of an endoscope, optionally a neuroendoscope, for cauterization. The endoscope includes a tip, an end effector connected to the tip, and a coil set disposed on the end effector. Cauterization involves actuating the end effector by applying a current to the coil set and ablating and/or killing tissue, optionally including tumor cells, using the Joule heating caused by the current applied to the coil set to close the end effector actuate. The description given above in relation to the endoscope applies mutatis mutandis to use for cauterization and vice versa.

Additionally or alternatively, a data processing device can be provided which is configured in such a way that the at least one of the methods described above is carried out at least partially.

Additionally or alternatively, a computer program may be provided, which computer program may include instructions which, when the program is downloaded from a computer, e.g. B. the data processing device, cause the computer to at least partially perform at least one of the methods described above.

Additionally or alternatively, a computer-readable (storage) medium can be provided, the computer-readable medium containing instructions which, when executed by a computer, cause the computer to at least partially carry out at least one of the methods described above.

Definitions of terms used in this specification are provided below, each specification being only one possible specific definition of many possible definitions of each term and thus is not intended to limit the scope of the disclosure to that specific definition.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one skilled in the art to which this disclosure pertains. Where a term has multiple definitions, unless otherwise specified, the definitions in this section shall control.

Wherever the phrases "for example," "such as," "including," and the like are used herein, the phrase "and without limitation" shall follow unless expressly stated otherwise. Similarly, "an example," "exemplary," and the like are not intended to be limiting.

The term "substantially" allows for deviations from the descriptor that do not adversely affect the intended purpose. Descriptive terms should be understood to be modified by the term "substantially" even if the word "substantially" is not expressly mentioned.

The term "approximately" in the context of a numerical value refers to the actually given value and to the approximation of that value which can reasonably be derived by one skilled in the art, including approximations based on the experimental and/or measuring conditions for that value.

The terms "comprising" and "including" and "comprising" and "including" (and similarly "includes", "including", "has" or "comprising" and "includes") and the like are used interchangeably and have the same meaning. In particular, each of the terms is defined in accordance with the standard definition of the term "comprising" in US patent law and is therefore construed as an open-ended term meaning "at least the following" and is also construed to include additional features, limitations, aspects etc. does not exclude. For example, "a device comprising components a, b and c" means that the device comprises at least components a, b and c. Likewise, the phrase “a process comprising steps a, b and c” means that the process comprises at least steps a, b and c.

Unless the context clearly requires otherwise, in the specification and claims, the words "comprise," "comprises," and the like are to be construed in an inclusive rather than exclusive or exhaustive sense; H. in the sense of "including but not limited to".

The term "method" as used herein may include a computer-implemented method. The term "computer-implemented Method” includes claims involving computers, computer networks or other programmable devices, wherein at least one feature is implemented using a program. A computer-implemented method may be a method implemented at least in part by a computing device, e.g. B. a computer running.

The term "control" can be defined as a process in a system in which one or more variables as input variables influence other variables as output variables due to the laws inherent in the system. Additionally or alternatively, the term "regulation" can be defined as a process in which a variable, the controlled variable (the variable to be controlled), is continuously recorded, compared with another variable, the reference variable, and influenced in the sense of an adjustment to the reference variable becomes.

The term "movement" can include any displacement or change in the position of a device, here the medical device, or its tip. In one possible interpretation, the movement can be a movement. A motion can be the phenomenon where an object, here the medical device, optionally its tip, changes its position with respect to space and time, optionally the magnetic field.

The term "determining" may include performing one or more mathematical operations to determine a desired output based on a given input in a particular manner.

The term "torque" can be the rotational equivalent of a linear force. The term "torque" can also be referred to as moment, moment of force, rotational force or rotational effect. Torque can represent the ability of a force to cause a change in rotational motion of a body, such as a wheel. B. the round shaped part of the medical device. Torque can be defined as the product of the magnitude of the force and the vertical distance of the line of action of the force from the axis of rotation. In three dimensions, torque can be a pseudo-vector; for point particles it is given by the cross product of the position vector (distance vector) and the force vector. The magnitude of the torque of a rigid body can depend on three quantities: the force applied, the lever arm vector connecting the point about which the torque is measured to the point of force application, and the angle between the force and lever arm vectors. Torque can be defined by the force applied to the tip of the medical device.

Instead of the term "current" or "current intensity" the term "electric current" or "electric current intensity" can also be used. An electric current is a flow of charged particles, such as B. Electrons or ions moving through an electrical conductor or a space. It is measured as the net flow of electric charge through a surface or into a control volume. The moving particles are called charge carriers, which can be one of several types of particles depending on the conductor. In electrical circuits, the charge carriers are often electrons moving through a wire. In semiconductors, it can be electrons or holes. In an electrolyte, the charge carriers are ions, while in a plasma, an ionized gas, they are ions and electrons. The SI unit of electric current or electric current is the ampere, i. H. the flow of electric charge through a surface at the rate of one coulomb per second. Electric currents create magnetic fields that can be used to move or actuate the medical device in the (external) magnetic field. In ordinary conductors they cause Joule heating.

The term "electromagnetic coil" can also be used instead of the term "coil". An electromagnetic coil can be an electrical conductor, e.g. B. a wire in the form of a coil, spiral or helix. An electric current can be passed through the wire of the coil to create a magnetic field. A current through any conductor creates a circular magnetic field around the conductor due to Ampere's law. An advantage of the coil shape can be that it increases the strength of the magnetic field created by a given current. The magnetic fields created by each turn of wire all pass through the center of the coil and add (superimpose) to create a strong field there. The more turns the wire has, the stronger the field generated can be and the stronger the Joule heating effect can be.

An optimization problem can be described as the problem of finding the essentially best solution out of all feasible solutions.

A medical device can be any device intended to be used for medical purposes. According to one possible definition, a medical device can be an instrument, apparatus, device, machine, facility, implant, in vitro reagent or a any other similar or related item, including a component or accessory, intended to diagnose, cure, mitigate, treat or prevent disease, disease or other conditions in humans or other animals and/or to affect the constitution or function of the human or other animal body and which do not achieve their primary intended purpose through a chemical action in or on the human or other animal body and which do not require metabolization to achieve their primary intended purpose. The term "medical device" may or may not include software functions. According to another possible definition, the term "medical device" can be any instrument, apparatus, device, software, material or other item used individually or in combination, including those specifically intended by the manufacturer for diagnostic and/or therapeutic purposes and necessary for their proper use Software designated by the manufacturer for use in humans or animals to diagnose, prevent, diagnose, prevent, monitor, treat, or alleviate disease, to diagnose, monitor, treat, alleviate, or compensate for an injury or disability, to investigate , intended to replace or modify the anatomy or a physiological process and/or to regulate conception and which does not achieve its intended main effect in or on the human and/or animal body by pharmacological, immunological or metabolic means, but which in its function tion can be supported by such means.

The term "electrical resistance" can also be used instead of the term "resistance". The resistance multiplied by the current can equal the (electrical) voltage.

A rod-shaped portion can be a portion or part of the medical device that can have a substantially circular cross-section. The rod-shaped section can have a cylindrical shape, with a height or length of the rod-shaped section exceeding the diameter of the rod-shaped section. The tip of the rod-shaped portion may be the outermost part of the rod-shaped portion in a forward direction of the medical device. The tip of the rod-shaped portion may include a peripheral area at or near the end of the outermost part of the rod-shaped portion. The rod-shaped part can comprise a tube or be realized with a tube. The tip may be referred to as the insertion tip of the medical device.

The Cosserat model can be based on Cosserat's rod theory. This approach can provide an essentially exact solution to the statics of a continuum robot, since it is not subject to any assumptions. It solves a series of equilibrium equations between the position, orientation, internal force and torque of the robot, here the medical device, optionally the rod-shaped section of it. Creating an accurate model that can predict the shape of a continuum robot makes it possible to properly control the shape of the robot.

A catheter can consist of a thin tube made of medical grade material that performs a variety of functions. Catheters are medical devices that can be inserted into the body to treat disease and/or perform a surgical procedure. By modifying the material or adjusting the way catheters are manufactured, it is possible to tailor catheters for cardiovascular, urinary, gastrointestinal, neurovascular and ophthalmic applications. The insertion of a catheter is called "catheterization". A catheter can include a thin, flexible tube (“soft” catheter), with catheters varying in stiffness depending on the application. This can be taken into account by the (Cosserat) model. The catheter may be designed to be inserted into a body cavity, duct or vessel, brain, skin or adipose tissue. Functionally, the catheter can provide drainage, administration of fluids or gases, access for surgical instruments, and/or a variety of other tasks, depending on the type of catheter. The catheter can be a so-called probe used in preclinical or clinical research for sampling lipophilic and hydrophilic compounds, protein bound and unbound drugs, neurotransmitters, peptides and proteins, antibodies, nanoparticles and nanocarriers, enzymes and vesicles becomes.

An endovascular catheter can be a catheter configured for endovascular aneurysm repair (EVAR). EVAR is a type of minimally invasive endovascular surgery used to treat pathologies of the aorta, most commonly an abdominal aortic aneurysm (AAA). When treating thoracic aortic disease, the procedure is called TEVAR ("Thoracic Endovascular Aortic-I Aneurysm Repair"). This procedure allows an expandable stent-graft to be placed in the aorta to treat aortic disease without operating directly on the aorta .

An endoscope is a medical device that can be used as an inspection tool. An endoscope may include an image sensor, an optical lens, a light source, and/or a mechanical device designed to look deep into the body through openings such as the mouth or anus.

A neuroendoscope can be an endoscope configured to be used for neuroendoscopy. It is a minimally invasive surgical technique that allows inspection (and optionally illumination) of angles in hidden parts of the surgical field, optionally allowing clear visualization and manipulation of anatomical structures. There are three main sub-disciplines of endoscopic neurosurgery: intraventricular neuroendoscopy for the treatment of occlusive hydrocephalus and other lesions in and around the ventricular system, transnasal neuroendoscopy including the various endoscopic endonasal approaches for pituitary and other skull base pathologies, and transcranial endoscope-guided microneurosurgery for various types of intracranial Tumors, cysts and neurovascular lesions. However, it should be noted that the present disclosure is not limited to these three areas.

A medical imaging device may be a device used for medical imaging. Medical imaging is the technique and process of imaging the inside of the body. Medical imaging can include radiology, which includes the imaging methods of X-ray radiography, magnetic resonance imaging, ultrasound, endoscopy, elastography, tactile imaging, thermography, medical photography and/or nuclear medicine functional imaging techniques such as positron emission tomography (PET) and single photon emission computed tomography (SPECT).

A magnetic resonance imaging scanner is a medical imaging device configured for magnetic resonance imaging (MRI). MRI is a medical imaging technique that can be used in radiology to create images of the body's anatomy and physiological processes. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves to create images of the organs in the body.

A working channel can be a channel, optionally circular in shape, located in the rod-shaped portion of the medial device. The working channel can extend through the entire rod-shaped section. The working channel can be used to transport a (medical) device, a gas and/or a fluid from an end of the medical device, which is optionally located outside the body, to the tip of the rod-shaped section. The working channel may permanently and/or temporarily house or at least partially house devices such as a camera, an electrical wire, and/or a light source.

Cauterization is the burning of body tissues using heat to stop bleeding or infection from an injury and/or to remove harmful cells.

character list

• 1 shows schematically in a perspective view a catheter in a starting position and four positions that differ from the starting position.
• 2 shows schematically the side turns of the catheter 1 .
• 3 shows schematically a cross section through a tip of the catheter 1 .
• 4 shows an endoscope schematically in a perspective view.
• 5 shows a gripper of the endoscope of FIG 4 in a closed state.
• 6 shows schematically in a plan view the gripper of the endoscope of FIG 4 in an open state.
• 7 FIG. 12 shows a flow diagram of a method for controlling the movement of a medical device in a magnetic field.
• 8th shows plots illustrating the current optimized regulator capacitances at various initial orientations and the corresponding joule heating effects when the coils are energized.
• 9 FIG. 12 shows a flow diagram of another method for controlling a movement of a medical device in a magnetic field.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

As required, detailed embodiments are disclosed herein; however, it should be understood that the disclosed embodiments are merely exemplary of the invention which may be embodied in various forms. The figures are not necessarily to scale and some features may be exaggerated to show detail of certain components. Therefore, specific structural and functional details disclosed herein are not to be taken as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously utilize the present invention.

A solution to the problem of Lorentz force induced heating without requiring active cooling or limiting the activation times of the microcoil for controlling a medical device is described below. This is achieved through a heat-reducing design and activation strategy that uses the previously mentioned 44 °C as a threshold for safe navigation in the body (assuming no arterial cooling occurs; worst-case scenario).

In 1 a catheter 1 is shown in a perspective view in five different states/positions. Furthermore, a Cartesian coordinate system is shown, which includes an X-axis, a Y-axis and a Z-axis, with an angle between these axes being 90° in each case. A magnetic field with a magnetic field vector B ₀ aligned parallel to the X-axis is present.

The catheter 1 comprises a rod-shaped section 3 and a tip 2 arranged at a distal end of the rod-shaped section 3, with a coil set 4 being arranged on the tip 2. FIG.

How out 3 , a cross-sectional view of the cylindrical tip 2, the catheter 1 comprises a working channel 5 which has a circular cross-section and extends from the tip 2 through the rod-shaped portion 3 so that devices, tissue etc. from outside a body, in which the catheter 1 is located, can be brought into the body through the working channel 5 and vice versa.

As in 1 is also in 3 a Cartesian coordinate system with an X-axis, a Y-axis and a Z-axis is drawn in, the angle between these axes being 90° in each case. The position of the axes X, Y, Z in 3 corresponds to the home/centre position of the car 1 in 1 . The X axis is therefore arranged parallel to a longitudinal direction of the tip 2 and the working channel 5 .

The coil set 4 comprises two axial coils 6 of round cross-section arranged around the working channel 5, a center of these two axial coils 6 being on the X-axis, ie the turns of the axial coils 6 are wound around the X-axis. In other words, a straight line that runs parallel to the longitudinal direction of the tip 2 intersects the center point of the two axial coils 6. In FIG 1 and 3 In the illustrated starting position of the catheter 1, in which the magnetic field vector B ₀ runs parallel to the X-axis, no Lorenz force can therefore be generated by the axial coils 6.

The coil set 4 comprises four lateral coils 7 - 10 arranged around the two axial coils 6 of the tip 2 such that a straight line is orthogonal to the longitudinal direction of the tip 2, ie arranged in the YZ plane and orthogonal to the X axis standing straight line, a midpoint of the respective lateral coil 7 - 10 intersects. In the in the 1 and 3 shown starting position of the catheter 1, in which the magnetic field vector B ₀ parallel to the X-axis, can therefore in the in the 1 and 3 shown starting position of the catheter 1, in which the magnetic field vector runs parallel to the X-axis, a Lorenz force is generated by the lateral coils 7 - 10 when they are energized. For this purpose, the catheter 1 comprises power lines 13 arranged on an outer periphery of an insulating material 12 (surrounding the lateral coils 7-10) of the tip 2 to supply the coil set 4 with electrical energy.

All the lateral coils 7-10 are arranged on the same flexible circuit board 14, which is wound around the axial coils 6, with a polymide layer 11 being arranged between the lateral coils 7-10 and the axial coils 6 (see Fig 3 ). How out 2 shows, the first and second of the side coils 7, 8 are connected in series and the third and fourth of the side coils 9, 10 are also connected in series. How out 3 As can be seen, the first and second of the lateral coils 7, 8 are arranged on opposite sides of the tip 2 and also the third and fourth of the lateral coils 9, 10 are arranged on opposite sides of the tip 2, ie the first and the second lateral coils 7,8 are arranged between the third and fourth lateral coils 9,10.

The Lorentz force generated by the lateral coils 7 - 10 causes the tip 2 of the catheter 1 to move essentially in the YZ plane, as shown in FIG 1 shown. Depending on the direction/polarity of the current (in 1 labeled +I and -I) tip 2 moves left or right when the first and the second lateral coil 7, 8 is energized, and up or down when the third and fourth lateral coils 9, 10 are energized. Of course, these movements can also be combined, e.g. B. by moving the tip 2 up and to the right at the same time. Four degrees of freedom can therefore be realized with this quadruple coil arrangement.

When an angle of 90° is reached, ie when the rod-shaped part 3 is bound so far that the magnetic field vector of the tip 2 B ₀ and the center of the side coils 7-10 are parallel, no Lorentz force is generated by the side coils 7-10 is generated and the axial coils 6 can be used to overcome this point.

The number of turns of the four lateral coils 7-10 may be between 2 and 40 (i.e. 2 and 40 inclusive) and between 4 and 30 (i.e. 4 and 30 inclusive) respectively. In the present case, however, the number of turns of the four side turns 7 - 10 is 7 (seven) each. Along with the rectangular Archimedean spiral, the planar coil form of the side turns 7-10 made by laser machining allows a very small diameter of the tip 2, e.g. B. about 1 mm can be achieved.

This is explained in more detail below based on a specific embodiment of the device, which is described for illustrative purposes only and is not intended to limit the scope of the disclosure, in particular the claims, in any way.

Lorentz force actuators have proven effective for various robotic/medical applications due to their precision, high force output, and scalability for soft device integration. These actuators use external magnetic fields to generate a force that is directly controlled for robot actuation. Therefore, Lorentz force actuators can use the high external magnetic field generated in MRI environments to develop robotic devices.

dargestellt, die verwendet werden kann, um das axiale Spulendrehmoment für einen Katheter mit Lorentzkraftbetätigung und gleich großen Spulenschleifen zu bestimmen. Bei der Implementierung von Sattelspulen (seitlichen Spulen) können Mikrospulen in die Katheterspitze integriert werden, um zusätzliche Freiheitsgrade (DoF) zu erhalten. Die Optimierung des Designs eines (z. B. MRT-gesteuerten) Katheters 1 mit einer Vier-Spulen-Konfiguration ermöglichte die Maximierung des erreichbaren Arbeitsbereichs (z. B. innerhalb des Herzens) unter Berücksichtigung bestimmter Beschränkungen wie der Anzahl der Spulensätze und der Stromeingänge.The integration of such actuators into catheters has been demonstrated using copper coils for Lorentz force-based control in blood vessels and in the heart. In this approach, controlling the current polarity of the microcoil leads directly to a deflection of tip 2 in the appropriate direction (see Fig 1 ). The generated magnetic moment m and the corresponding torque T can be determined using the number of coil loops N, the current I and the surface normal vector A of a coil loop and the magnetic field vector (e.g. in an MR scanner) (B ₀ = (0 , 0, B ₀ )), where B ₀ is the (e.g. uniform, permanent, ie static) magnetic field (e.g. inside the MRI). This relationship is given by (equation 1) $$\text{T}=\text{m}\times {\text{<figure-callout id="0" label="B" filenames="DE202022104403U1\_0026.png" state="{{state}}">B</figure-callout>}}_0=NI\left(\text{A}\times {\text{B}}_0\right)$$

which can be used to determine the axial coil torque for a Lorentz force actuation catheter with equal sized coil loops. When implementing saddle coils (side coils), microcoils can be integrated into the catheter tip to provide additional degrees of freedom (DoF). Optimizing the design of a (e.g. MRI-guided) catheter 1 with a four-coil configuration allowed the achievable working area to be maximized (e.g. inside the heart) given certain constraints such as the number of coil sets and the current inputs .

However, maximizing the number of coil turns and area may not be feasible for navigating narrow blood vessels. To improve on the two existing design schemes, laser machining can be used in conjunction with the Archimedean spiral coil to create an in-plane micro-coil design with a quad configuration (see Fig 2 ).

The proposed design enables more compact and significantly smaller catheter diameters, e.g. up to 1 mm, than previously proposed designs while achieving comparable controllability. With this approach, both saddle/side coil sets are integrated in the same circumferential plane without introducing any additional layer thickness compared to the prior art.

und die entsprechende Gesamtleitungslänge zur Schätzung des Stromverbrauchs (Gleichung 3) $$L_{\text{coil}}={\displaystyle \sum _{i=0}^{N-1}2\left(W_c-w-2i\left(2t+w\right)-2w\right)}$$

The following are the equations for a rectangular Archimedean spiral to estimate the magnetic moment of the microcoil. The approximate effective area of all coil loops 7 - 10 can be expressed as follows (Equation 2) $$A_{\text{total}}={\displaystyle \sum _{i=0}^{N-1}\left(L_c-w-i\left(w+2t\right)\right)\left(W_c-w-i\left(w+2t\right)\right)}$$

and the corresponding total line length to estimate power consumption (equation 3) $$L_{\text{coil}}={\displaystyle \sum _{i=0}^{N-1}2\left(W_c-w-2i\left(2t+w\right)-2w\right)}$$

Substituting Equation (2) into Equation (1) gives the magnetic moment of a single saddle coil $$\text{m}=I{A}_{\text{total}}$$

Achieving larger bending angles for Lorentz force based actuation requires maximizing the magnetic moment of the coil. As can be seen from the equations above, tuning various parameters (e.g. coil turns, current, catheter diameter) can affect performance. Generally, a larger number of coil turns means better bending performance due to the larger coil area. However, when the current is limited to the heating threshold (e.g. 0.5 W) to mitigate heating effects, there is an inverse relationship between the magnetic moment and the number of turns of the coil. In other words, a lower coil turn count is ideal for heating mitigation, but requires higher currents to generate such electromagnetic torque, resulting in undesired heating of the power lines 13 . However, the use of larger power lines 13 to reduce heating increases structural rigidity depending on wire size and thus has undesirable effects on catheter steerability. Therefore, a microcoil turn count in the ranges described above, particularly about 7, can be used to maximize the magnetic moment while remaining within established current ratings for power lines 13 and an acceptable range of stiffness for (e.g., endovascular) catheters.

In the following, an endoscope 15, here a neuroendoscope, which uses the same quadruple coil construction as the catheter 1, is illustrated in FIG 4 described in detail. The above description applies analogously to the endoscope 15 and is therefore not repeated. A Cartesian coordinate system with an X-axis, a Y-axis and a Z-axis is also shown here, with an angle between these axes being 90° in each case. A magnetic field with a magnetic field vector B ₀ aligned parallel to the X-axis is present.

The endoscope 15 comprises a tip 16, a rod-shaped section 151, a coil set 17 surrounding the tip 16, which has already been described above in relation to the coil set 4 surrounding the tip 2 of the catheter 1, and (not shown) power lines, which are arranged to supply electrical energy to the coil set 17 in the same way as the power lines 13 of the catheter 1 described above an opening 20 of an irrigation channel extending through the endoscope 15 .

The endoscope 15 includes an end effector 21, here a gripper, which is connected to the tip 16 of the endoscope 15. The end effector is actuated by Lorentz force. Therefore, the gripper 21 includes a further set of coils 22 for actuating the jaws 23 of the gripper 21.

This is in the 5 and 6 shown in detail. The two jaws 23 (in the 5 and 6 only one is shown) are pivotally connected to one another via a rotary joint 24 . The additional coil set 22 each includes a lateral coil, which is arranged on one of the two jaws 23, so that by applying a current to the lateral coils of the additional coil set 22, the jaws 23 can be opened or closed by rotating about the pivot 24 ( 5 shows the closed and 6 the open state).

In the following, a method for controlling a movement of the medical devices described above, ie the endoscope 15 and the catheter 2, in a magnetic field will be described in detail. A flowchart of the procedure is in 7 shown. The method is advantageous because Joule heating can remain an issue even with the medical device design described above and therefore optimizing the current distribution of the microcoils (saddle/axial) can affect the performance of the medical device 1,15.

Both medical devices 2, 15 have in common that they have a flexible, essentially rod-shaped section 3, 151. The movement of the tip 2, 16 includes a deformation of the rod-shaped section 3, 151, which leads to a movement of the tip 2, 16 of the rod-shaped section 3, 151. Therefore, the principles described below can be applied to both the catheter 2 and the endoscope 15.

In a first step S1 of the method, a torque is determined which has to be applied to the medical device 1, 15 in order for the tip 2, 16 of the medical device 1, 15 to carry out the movement.

Determining the torque may involve solving a first optimization problem to minimize the torque to be applied to the medical device 1, 15 in order for the tip 2, 16 of the medical device 1, 15 to perform the movement.

The solution to the first optimization problem may involve determining the deformation of the rod-shaped section 3, 151 required for the movement of the tip 2, 16 of the rod-shaped section 3, 151 from an actual position to a desired position such that a torque which required for the deformation of the rod-shaped section 3, 151 is minimized. The torque that must be applied to the medical device 1,15 in order for the medical device to perform the movement is then adjusted to be equal to the torque that is required for the rod-shaped section 3,151 to deform.

The deformation required for the movement of the tip 2, 16 of the rod-shaped section 3, 151 from the actual position to the desired position can be determined using a model, optionally a Cosserat model, which describes the non-linear dynamics of the rod-shaped section 3, 151 represents.

This is explained in detail below based on a specific implementation of the disclosure, which is described for explanation purposes only and is not intended to limit the scope of the disclosure, in particular the claims, in any way.

Der diskretisierte Zustandsvektor für jedes Segment i enthält die Segmentposition (p_iℝ³), Orientierung (R_i ∈ SO(3)), Dehnungskraft (n E ℝ³) und das Schermoment (m ∈ ℝ³), die in einem Vektor ausgedrückt werden können y_i = [p_i, R_i, n_i, m_i]. Die Rotationsmatrix wird in einem festen Koordinatensystem (z. B. MRT) zusammen mit zwei zusätzlichen Koordinatensystemen L definiert: dem Kontrollsystem C, das die Ausgangsposition der freien Länge des Katheters darstellt, und dem System T, das den Beginn der Mikrospulen lokalisiert. Daher kann ein System nichtlinearer gewöhnlicher Differentialgleichungen (ODEs) wie folgt ausgedrückt werden (Gleichungen 5 bis 8) $${\dot{\text{p}}}_{\text{i}}={\text{R}}_{\text{i}}{\text{v}}_{\text{i}}$$

$${\dot{\text{R}}}_{\text{i}}={\text{R}}_{\text{i}}{\text{u}}_{\text{i}}$$

$${\dot{\text{n}}}_{\text{i}}=-\rho Ag$$

$${\dot{\text{m}}}_{\text{i}}=-{\dot{\text{p}}}_{\text{i}}\times {\text{n}}_{\text{i}}$$

wobei v und u Tangenten- und Krümmungsvektoren sind, die wie folgt definiert sind: v = ẑ + K₁R^T n und u = K₂R^T m m, wobei ${{\mathbb{Z}}_i}_{}$

der Einheitsvektor im lokalen Koordinatensystem ist, K₁ = diag(GA,GA,EA) und K₂ = diag(EI_A, EI_A,GJ). G, A, E, I_A, und J stehen für den Schermodul, die Querschnittsfläche, den Elastizitätsmodul, das Flächenträgheitsmoment bzw. das polare Trägheitsmoment. Vorwärtskinematik des Katheters, Y = f (n₀, m₀), kann durch numerische Integration mit dem Runge-Kutta-Algorithmus vierter Ordnung berechnet werden, wenn die Anfangsbedingungen des Katheters gegeben sind: R₀ = R_C, p₀ = p_C, n₀ = n_C, m₀ = m_C. Obwohl das vorwärtsgerichtete kinematische Modell in Form eines Anfangswertproblems für die Simulation der Katheterbewegung bei gegebener Basisdrehung bzw. Basisdyname nützlich ist, wird ein inverses kinematisches Modell benötigt, um das minimale Katheterdrehmoment zum Erreichen der gewünschten Orientierungen zu bestimmen. Ein inverses kinematisches Modell in Form eines Randwertproblems (BVP) kann mit den folgenden Randbedingungen formuliert werden: R₀ = R_C, p₀ = p_C, n_τ = 0, m_τ = τ_des und R_τ = R_des. Hier, n_τ und m_τ als die magnetische Drehung bzw. magnetische Dyname an der Spitze 2 des Katheters 1 ausgedrückt. Da die auf die Katheterspitze wirkende magnetische Gradientenzugkraft im Vergleich zur Größe einer verteilten Lorentzkraft vernachlässigbar ist, wird angenommen, dass nur ein Drehmoment an der Spitze 2 auftritt. Daher wird die inverse Kinematik für das gewünschte Spitzendrehmoment (τ_des= IK(R_des)) durch Lösen des folgenden Optimierungsproblems für das Spitzendrehmoment berechnet (Gleichung 9) $$\underset{\text{Y}}{\text{argmin}}{\Vert {\text{R}}_{T,des}\boxminus {\text{R}}_T\Vert }_2^2+{\Vert {\tau }_{\text{des}}\Vert }_2^2$$

$$\text{s}\text{.t}\text{.Y}=ƒ\left({\text{n}}_0,{\text{m}}_0\right)$$

wobei das eingerahme Minuszeichen (

: SO(3)×SO(3)→ℝ³) der Rotationsdifferenzoperator ist, der auf dem in der Lie-Algebra definierten Matrixlogarithmus beruht. Das Spitzendrehmoment ist τ_des = m_N. Die Optimierung wird in Echtzeit mit der in C++ implementierten iterativen Levenberg-Marquardt-Methode gelöst, wobei die Vorwärtskinematik des Katheters als Schussfunktion verwendet wird. Es ist wichtig zu beachten, dass der

-Fehler für die Stabilität der Lösung in der Nähe von Singulärwerten wesentlich sein kann, und die quadratische Funktion für das Spitzendrehmoment reguliert die Kostenfunktion, um inverse kinematische Lösungen mit Schleifen zu eliminieren. Die obige Beschreibung gilt mutatis mutandis für das Endoskop.Steerable catheters are subject to large deformations/movements during surgical procedures. A method for modeling such motions, commonly used to model elastic bars and continuum bars, is the Cosserat bar theory. The Cosserat bar model integrates the traditional bending and twisting of Kirchhoff bars with added strain and shear to capture full beam dynamics. The Cosserat model accurately maps the nonlinear dynamics of elastic bars with different materials and geometries. Catheter 1 can be modeled as a cantilever beam subjected to an external torque and peak force. The state of the catheter can be represented by a set of N discretized segments $\text{Y}={\left[y_0^T,y_1^T,...y_n^T\right]}_N^T.$

The discretized state vector for each segment i contains the segment position (p _i ℝ ³ ), orientation (R _i ∈ SO(3)), extension force (n E ℝ ³ ), and shear moment (m ∈ ℝ ³ ), expressed in a vector can become y _i = [p _i , R _i , n _i , m _i ]. The rotation matrix is defined in a fixed coordinate system (e.g. MRI) together with two additional coordinate systems L: the control system C, which represents the starting position of the free length of the catheter, and the system T, which locates the beginning of the microcoils. Therefore, a system of nonlinear ordinary differential equations (ODEs) can be expressed as (Equations 5 to 8) $${\dot{\text{p}}}_{\text{i}}={\text{R}}_{\text{i}}{\text{v}}_{\text{i}}$$

$${\dot{\text{R}}}_{\text{i}}={\text{R}}_{\text{i}}{\text{and}}_{\text{i}}$$

$${\dot{\text{n}}}_{\text{i}}=-\rho AG$$

$${\dot{\text{m}}}_{\text{i}}=-{\dot{\text{p}}}_{\text{i}}\times {\text{n}}_{\text{i}}$$

where v and u are tangent and curvature vectors defined as follows: v = ẑ + K ₁ R ^T n and u = K ₂ R ^T mm, where ${{\mathbb{Z}}_i}_{}$

is the unit vector in the local coordinate system, K ₁ = diag(GA,GA,EA) and K ₂ = diag(EI _A ,EI _A ,GJ). G, A, E, I _A , and J represent shear modulus, cross-sectional area, elastic modulus, area moment of inertia, and polar moment of inertia, respectively. Catheter forward kinematics, Y = f(n ₀ , m ₀ ), can be calculated by numerical integration using the fourth order Runge-Kutta algorithm given the initial conditions of the catheter: R ₀ = _RC , p ₀ = _pC , n ₀ = n _C , m ₀ = m _C . Although the forward kinematic model, in the form of an initial value problem, is useful for simulating catheter motion given the base rotation or base dynamics, an inverse kinematic model is needed to determine the minimum catheter torque to achieve the desired orientations. An inverse kinematic model in the form of a boundary value problem (BVP) can be formulated with the following boundary conditions: R ₀ = R _C , p ₀ = p _C , n _τ = 0, m _τ = τ _des and R _τ = R _des . Here, n _τ and m _τ are expressed as the magnetic rotation and magnetic dynama at the tip 2 of the catheter 1, respectively. Since the magnetic gradient pull force acting on the catheter tip is negligible compared to the magnitude of a distributed Lorentz force, it is assumed that only torque at the tip 2 occurs. Therefore, the inverse kinematics for the desired peak torque (τ _des = IK(R _des )) is calculated by solving the following peak torque optimization problem (Equation 9) $$\underset{\text{Y}}{\text{argmin}}{\Vert {\text{R}}_{T,\mathrm{i.e}es}\boxminus {\text{R}}_T\Vert }_2^2+{\Vert {\tau }_{\text{of}}\Vert }_2^2$$

$$\text{s}\text{.t}\text{.Y}=ƒ\left({\text{<figure-callout id="0" label="n" filenames="DE202022104403U1\_0026.png" state="{{state}}">n</figure-callout>}}_0,{\text{m}}_0\right)$$

where the framed minus sign (

: SO(3)×SO(3)→ℝ ³ ) is the rotation difference operator based on the matrix logarithm defined in the Lie algebra. The peak torque is τ _des = m _N . The optimization is solved in real-time with the iterative Levenberg-Marquardt method implemented in C++, using the forward kinematics of the catheter as the shot function. It is important to note that the

-Errors essential for the stability of the solution near singular values and the peak torque quadratic function adjusts the cost function to eliminate inverse kinematic solutions with loops. The above description applies mutatis mutandis to the endoscope.

In a second step S2 of the method, a minimum current is determined by solving a second optimization problem, which must be supplied to each coil 6, 7-10 of the coil set 4, 17 in order to achieve the specific torque (τ_des).

This is explained in detail below based on a specific implementation of the disclosure, which is described for explanation purposes only and is not intended to limit the scope of the disclosure, in particular the claims, in any way.

$$\text{s}\text{.t}\text{.}{\tau }_{\text{coils}}={\tau }_{\text{side}\mathrm{,1}}+{\tau }_{\text{side}\mathrm{,2}}+{\tau }_{\text{axial}}$$

wobei I = [I_side,1, I_side,2, I_axial] die Ströme der Sattel-/sie und der axialen Spulen und τ_coil das Gesamtdrehmoment darstellt, das jeweils von eine Sattel- und eine axialen Spulensatz 6, 7 - 10 erzeugt wird. Der erste Term der Kostenfunktion dient der Übereinstimmung zwischen dem gewünschten Spitzendrehmoment und dem Gesamtdrehmoment der Spule, und der zweite Term ist der Kostenfaktor für den Stromverbrauch der Spule, wobei R = diag(R_side,1, R_side,2, R_axial] der Widerstand der Spulen ist. Aufgrund des Größenunterschieds zwischen dem Drehmomentfehler und den induzierten Strömen wird eine α-Konstante einbezogen (die mit Hilfe einer Rastersuche bestimmt wird, um die beste Ausgelichsrechnung (fitting) zu finden; 1 × 10-6). Auch diese Optimierung wird mit dem Levenberg-Marquardt-Verfahren gelöst. 8 zeigt einen Vergleich zwischen der Betätigung von Spulen mit gleichverteiltem Strom und dem optimalen Ansatz. In 8 definiert A-i) den Anfangswinkel zwischen der Katheterspitze 2 und B₀ den Feldvektor, y, und die endgültige Ausrichtung der Spitze, 0, nach der Anregung. A,B) stellen dar, wann die Vierfach-Konfigurations-Mikrospule (QCM) mit der Ausrichtung auf und senkrecht zu dem B₀ Feld ausgerichtet ist. Der Strom wurde zwischen den beiden Anregungsschemata in (A-i) und (B-i) verglichen: gleichmäßig verteilter (E.D.) Strom und optimierte Stromverteilung zwischen den Spulen. Der eingesparte Strom bei Verwendung des optimalen Ansatzes ist gleich der Fläche zwischen den beiden Kurven. (A-ii) und (B-ii) zeigen die Stromverteilung bei beiden Betätigungsschemata. (A-iii) und (B-iii) zeigen die eingesparte Gesamtleistung bei Verwendung des leistungsoptimierten Reglers. Die Optimierung der Stromverteilung minimiert den Stromverbrauch und die Joule'schen Erwärmungseffekte, indem die axialen Spulen 6 beim Erreichen von Winkeln zwischen 90° und 160° bevorzugt werden (8A-ii), was zu einem Anstieg des eingesparten Stroms führt. Bei einem Winkel von mehr als 160° erzeugen die seitlichen Spulen 7-10 ein größeres Drehmoment, was zu einer Umverteilung des Stroms und damit zu einem Verlust des eingesparten Stroms führt. Dieses Phänomen wird auch beobachtet, wenn y = 90° (8B-ii); zwischen 20° und 50° werden die axialen Spulen 6 bevorzugt. Bei Winkeln unter 20° kommt es zu einer Umverteilung des Stroms in Richtung der seitlichen Spulen 7 - 10, da der Katheter parallel zum Vektor ausgerichtet ist. B₀ Feldvektor ausrichtet. Aufgrund der Unterschiede im Spulenwiderstand zwischen den Sattel-/seitlichen Spulen und den axiale Spulen 6, 7 - 10 können erhebliche Stromänderungen beobachtet werden (8A-iii, B-iii). 8A-iii zeigt, dass bei kleineren Winkeln ein Strom von 3 mW und bei größeren Winkeln bis zu 50 mW eingespart wird, wenn der Katheter 1 auf den B₀ Feldvektor ausgerichtet ist. 8B-iii zeigt einen eingesparten Strom von 10 mW, wenn y = 90° und der Katheter 1 parallel zum B₀ field-Vektor ausrichtet. Unabhängig von der anfänglichen Ausrichtung kann ein eingesparter Strom von 25 % nachgewiesen werden. Dieser eingesparte Strom verbessert die allgemeine Sicherheit des Katheters während der Steuerung bei niedrigen Drehwinkeln und vergrößert den Arbeitsbereich des Katheters bei höheren Winkeln um bis zu 10°. Die obige Beschreibung gilt mutatis mutandis für das Endoskop 15.The generation of heat based on micro-coils can be reduced by optimally distributing the current to the lateral and axial coils 6, 7-10. The peak orientation controller therefore includes a two-step optimization scheme: 1) inverse kinematics to determine the torque using equation (9) and 2) current distribution of the saddle/axial coils. A power-optimized current distribution problem is formulated as a nonlinear quadratic optimization (Equations 10 and 11) $$\text{I}*=\underset{\text{I}}{\text{argmin}}{\Vert {\tau }_{\text{coils}}-{\tau }_{\text{of}}\Vert }^2+a{\Vert \text{I}\Vert }_{\text{<figure-callout id="2" label="R" filenames="DE202022104403U1\_0019.png,DE202022104403U1\_0021.png" state="{{state}}">R</figure-callout>}}^2$$

$$\text{s}\text{.t}\text{.}{\tau }_{\text{coils}}={\tau }_{\text{side}\mathrm{,1}}+{\tau }_{\text{side}\mathrm{,2}}+{\tau }_{\text{axial}}$$

where I = [I _side,1 , I _side,2 , I _axial ] represents the currents of the saddle and axial coils and τ _coil represents the total torque generated by a saddle and an axial coil set, respectively 6, 7 - 10 is produced. The first term of the cost function is for the correspondence between the desired peak torque and the total torque of the coil, and the second term is the cost factor for the current consumption of the coil, where R = diag(R _side,1 , R _side,2 , R _axial ] der Resistance of the coils is Due to the magnitude difference between the torque error and the induced currents, an α-constant (determined using a grid search to find the best fitting; 1 × 10-6) is included. Also this optimization is solved using the Levenberg-Marquardt method. 8th shows a comparison between actuating coils with evenly distributed current and the optimal approach. In 8th Ai) the initial angle between the catheter tip 2 and B ₀ defines the field vector, y, and the final orientation of the tip, 0, after excitation. A,B) represent when the quad configuration microcoil (QCM) is oriented with the orientation on and perpendicular to the B ₀ field. The current was compared between the two excitation schemes in (Ai) and (Bi): evenly distributed (ED) current and optimized current distribution between the coils. The power saved using the optimal approach is equal to the area between the two curves. (A-ii) and (B-ii) show the current distribution in both actuation schemes. (A-iii) and (B-iii) show the total power saved when using the power-optimized controller. Optimizing the current distribution minimizes power consumption and Joule heating effects by favoring the axial coils 6 when reaching angles between 90° and 160° ( 8A - ii ), resulting in an increase in saved electricity. At an angle of more than 160°, the side coils 7-10 generate a greater torque, which leads to a redistribution of the current and a loss of the saved current. This phenomenon is also observed when y = 90° ( 8B - ii ); between 20° and 50° the axial coils 6 are preferred. At angles below 20°, the current is redistributed in the direction of the lateral coils 7 - 10, since the catheter is aligned parallel to the vector. B ₀ field vector aligns. Due to the differences in coil resistance between the saddle/side coils and the axial coils 6, 7 - 10, significant current changes can be observed ( 8A - iii , B-iii). 8A - iii shows that a current of 3 mW is saved at smaller angles and up to 50 mW at larger angles when the catheter 1 is aligned with the B ₀ field vector. 8B - iii shows a saved power of 10 mW when y = 90° and the catheter 1 aligns parallel to the B ₀ field vector. Regardless of the initial orientation, a 25% electricity saving can be demonstrated. This saved power improves the overall safety of the catheter during steering at low angles of rotation and increases the working range of the catheter by up to 10° at higher angles. The above description applies mutatis mutandis to the endoscope 15.

In a third step S3 of the method, each coil of the coil set 6, 7-10 is supplied with the specific minimum current (I_side1, I_side2, I_axial), so that the tip 2, 16 of the medical device 2, 15 carries out the movement.

If the medical device is the endoscope 15 , the third step S3 can include the actuation of the end effector 21 by applying a current to the additional coil set 22 . If the end effector 21 comprises the gripping forceps, the actuation of the end effector 21 can open and/or close the jaws 23 of the gripping tongs 21 by applying the current to the other coil set 22 include. The opening may be a movement in which the jaws of the gripper are moved away from each other by rotating about the pivot 24 and the closing may be a movement in which the jaws 23 of the gripper are moved towards each other by rotating about the pivot 24 . The method may involve ablating and/or killing tissue, optionally containing tumor cells, such as e.g. cancerous brain tumor cells, using the Joule heating caused by the current supplied to the further coil set 22 to actuate the end effector 21, optionally for opening and closing the jaws 23 of the gripper.

The Joule heating caused by the actuation of the gripper can be used in the third step S3 of the method for cauterization. More specifically, cauterization involves actuating the end effector by applying a current to the further coil set 22 and ablating and/or killing tissue, optionally including tumor cells, using the Joule heating generated by the current supplied to the coil set for actuation of the end effector.

This is explained in detail below based on a specific implementation of the disclosure, which is described for explanation purposes only and is not intended to limit the scope of the disclosure, in particular the claims, in any way.

With the proposed design of the MRI-guided endoscope 15 described above, the use of the high (3-7 T), external magnetic field of an MR scanner for thermally-controlled control within the ventricular system of the brain becomes possible. The Lorentz force based gripper can be used for manipulation and ablation of diseased tissue, i. H. for cauterization. Feasibility studies show that the neuroendoscope 15 can be precisely steered in the lateral ventricle to localize a tumor using both MRI and endoscopic guidance. The results also show that gripping forces of up to 31 mN are possible and a power consumption of only 0.69 mW can cause cancerous tissue ablation.

In 9 1 is a flowchart for another method for controlling the movement of the medical device 1, 15 in a static magnetic field generated by a medical imaging device, here a magnetic resonance imaging device. The method comprises the steps S1 - S3 described above. The method further includes, in a first step S0, receiving user input related to the movement via a user interface, which optionally includes a joystick. The user interface can be connected to the medical device 1,15. The method further comprises a fourth step S4, which is carried out simultaneously with steps S0 - S4, this step S4 continuously determining an actual position of the medical device 1, 15, optionally the tip 2, 16 thereof, using medical imaging, here the MRT, and the continuous display of the determined position of the medical device on a display device in relation to a tissue, optionally of a human or an animal, in which the medical device 1, 15 is located. The display device can be connected to the medical imaging device.

Claims (43)

A device configured to perform a method of controlling movement of a medical device in a magnetic field, the medical device comprising a coil set, the method comprising: - determining a torque that must be applied to the medical device in order for the medical device to perform the movement, - determining a minimum current that must be supplied to each coil of the coil set in order to obtain the determined torque by solving an optimization problem, and - Supply each coil of the coil set with the specified minimum current so that the medical device performs the movement. device after claim 1 , where the optimization problem is defined as follows: $$\text{I}*=\underset{\text{I}}{\text{argmin}}{\Vert {\tau }_{\text{coils}}-{\tau }_{\text{of}}\Vert }^2+a{\Vert \text{I}\Vert }_{\text{R}}^2$$

where: - I represents a current supplied respectively to each coil of the coil set, - τ _coils represents a total torque generated by the coil set when supplied with the current I, - τ _des represents the torque applied to the medical device must be applied in order for the medical device to perform the movement, and - R represents a resistance of each coil of the coil set. device after claim 1 or 2 , wherein determining the torque includes solving another optimization problem to minimize the torque that needs to be applied to the medical device such that the medical device performs the movement. Device according to one of Claims 1 until 3 wherein the medical device comprises a flexible, substantially rod-shaped section and the movement comprises a deformation of the rod-shaped section resulting in a movement of a tip of the rod-shaped section. device after claim 4 wherein the solving of the further optimization problem comprises: - determining the deformation of the rod-shaped section required for the movement of the tip of the rod-shaped section from an actual position to a desired position such that a torque required for the deformation of the rod-shaped section is minimized, and - determining the torque that must be applied to the medical device in order for the medical device to perform the movement corresponding to the torque required for the deformation of the rod-shaped section. device after claim 5 , wherein the deformation required to move the tip of the rod-shaped section from the actual position to the desired position is determined using a model, optionally a Cosserat model, representing the non-linear dynamics of the rod-shaped section. A device configured to perform a method for controlling movement of a medical device in a magnetic field, the medical device comprising a coil set, the method comprising: - determining a torque to be applied to the medical device, such that the medical device performs the movement, wherein determining the torque (τ _des ) that needs to be applied to the medical device comprises solving an optimization problem to minimize the torque that needs to be applied to the medical device, so that the medical device performs the movement, - determining a current that must be supplied to the coil set in order to obtain the specified torque, and - supplying the coil set with the specified current so that the medical device performs the movement. device after claim 7 wherein the medical device comprises a flexible, substantially rod-shaped portion, and the movement comprises deformation of the rod-shaped portion resulting in movement of a tip of the rod-shaped portion. device after claim 8 wherein the solving of the optimization problem comprises: - determining the deformation of the rod-shaped section required for the movement of the tip of the rod-shaped section from an actual position to a desired position such that a torque required for the deformation of the rod-shaped section is required , is minimized, and - determining the torque (τ _des ) that must be applied to the medical device in order for the medical device to perform the movement corresponding to the torque required for the deformation of the rod-shaped section. device after claim 9 , wherein the deformation required to move the tip of the rod-shaped section from the actual position to the desired position is determined using a model, optionally a Cosserat model, representing the non-linear dynamics of the rod-shaped section. Device according to one of Claims 1 until 10 , wherein the method comprises receiving user input related to movement of the medical device via a user interface, optionally including a joystick. Device according to one of Claims 1 until 11 , the method comprising: - determining an actual position of the medical device, optionally the tip thereof, using medical imaging, and - automatically controlling the movement based on the determined actual position. Device according to one of Claims 1 until 12 , wherein the method comprises displaying an actual position of the medical device and/or a position of the medical device after performing the movement on a display device connected to the medical device. device after Claim 13 , wherein the method of displaying the actual position of the medical device and/or the position of the medical device after performing the movement relative to tissue, optionally human or animal, on the display associated with the medical device. Device according to one of Claims 1 until 14 , wherein the magnetic field is generated by a medical imaging device, optionally a magnetic resonance imaging device. Device according to one of Claims 1 until 15 , where the magnetic field is a static magnetic field. Device according to one of Claims 1 until 16 , wherein the medical device comprises a catheter, optionally an endovascular catheter. device after Claim 17 , wherein the catheter comprises: - a tip optionally comprising a working channel extending through the tip of the catheter, - the coil set surrounding the tip, and - power cables arranged to supply the coil set with electrical energy take care of. device after Claim 18 , wherein the coil set comprises four lateral coils arranged around the tip such that a straight line orthogonal to the longitudinal direction of the tip intersects a center point of the respective lateral coil. device after claim 19 , wherein: - a first and a second of the side coils are connected in series, - a third and a fourth of the side coils are connected in series, - the first and second of the side coils are arranged on opposite sides of the tip, and - the third and fourth side coils are located on opposite sides of the tip and between the first and second side coils. Device according to one of claims 17 until 20 , wherein a number of turns of at least one of the four lateral coils is between 2 and 40, optionally 4 and 30, further optionally 7. Device according to one of claims 17 until 21 , wherein the coil set comprises at least one axial coil arranged around the tip such that a straight line parallel to the longitudinal direction of the tip crosses a midpoint of the at least one axial coil. Device according to one of claims 17 until 22 wherein at least one of the coils of the coil set has been processed by laser machining, laser lithography and/or manual winding. Device according to one of claims 17 until 23 , wherein at least one of the coils of the coil set has an, optionally rectangular, Archimedean spiral shape. Device according to one of claims 17 until 24 wherein at least one of the coils of the coil set has an in-plane configuration. Device according to one of claims 19 until 25 , whereby the four lateral coils are arranged on the same, optionally flexible, printed circuit board. Device according to one of Claims 1 until 16 , wherein the medical device comprises an endoscope, optionally a neuroendoscope. device after Claim 27 , wherein the endoscope comprises: - a tip optionally comprising a working channel extending through the tip of the endoscope, - the coil set surrounding the tip, and - power cables arranged to supply the coil set with electrical energy take care of. device after claim 28 , wherein the coil set comprises four lateral coils arranged around the tip such that a straight line orthogonal to a longitudinal direction of the tip intersects a midpoint of the respective lateral coil. device after claim 29 , wherein: - a first and a second of the side coils are connected in series, - a third and a fourth of the side coils are connected in series, - the first and second of the side coils are arranged on opposite sides of the tip, and - the third and fourth side coils are located on opposite sides of the tip and between the first and second side coils. Device according to one of claims 27 until 30 , wherein the number of turns of at least one of the four lateral coils is between 2 and 40, optionally 4 and 30, further optionally 7. Device according to one of claims 27 until 31 , wherein the coil set comprises at least one axial coil so positioned around the tip arranged is that a straight line running parallel to the longitudinal direction of the tip crosses a center point of the at least one axial coil. Device according to one of claims 27 until 32 , wherein at least one of the coils of the coil set has been produced by laser machining, laser lithography and/or manual winding. Device according to one of claims 27 until 33 , wherein at least one of the coils of the coil set has an optionally rectangular Archimedean spiral shape. Device according to one of claims 27 until 34 wherein at least one of the coils of the coil set has an in-plane shape. Device according to one of claims 29 until 35 , whereby the four lateral coils are arranged on the same, optionally flexible, printed circuit board. Device according to one of claims 28 until 36 wherein the endoscope includes an end effector connected to the tip of the endoscope. device after Claim 37 , wherein the end effector comprises a further set of coils for actuation of the end effector. device after Claim 38 , wherein the means comprises an actuation of the end effector by applying a current to the further set of coils. device after Claim 38 or 39 , wherein: - the end effector comprises a gripper with two jaws pivotally connected to one another, and - the further coil set comprises at least one lateral coil which is arranged on each of the two jaws. device after Claim 40 wherein the actuation of the end effector comprises opening and/or closing the jaws of the gripper by applying the current to the further set of coils. Device according to one of Claims 39 until 41 wherein the means comprises ablating and/or killing tissue, optionally comprising tumor cells, using Joule heating caused by the current supplied to the further set of coils for actuating the end effector. Device according to one of claims 27 until 42 , wherein the tip of the endoscope comprises: - a camera, - an illumination device, optionally comprising an LED, and/or - an opening of an irrigation channel extending through the endoscope.

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