Magnetic positioning system for intracardiac ultrasound catheter

Abstract

The utility model provides a magnetic positioning system for an intracardiac ultrasound catheter, which is characterized by comprising a puncture needle, a mechanical arm and a magnetic positioning device, the ultrasonic catheter is an independent tubular device, and an ultrasonic device and a magnetic device are embedded in a far-end catheter body of the ultrasonic catheter; and a robot arm. The mechanical arm is provided with three modules: a signal acquisition module comprising an in-vitro sensing device; the position calculation module comprises a processor and a memory in which a target positioning algorithm is stored; and the catheter tracking module comprises a PID control chip. The magnetic device is arranged in the ultrasonic catheter, and the sensing device is arranged at the tail end of the mechanical arm, so that the system structure is simpler, and the positioning accuracy can be better guaranteed.

Description

Technical Field

[0001] This utility model relates to the field of medical equipment technology, and in particular to a magnetic positioning system for intracardiac ultrasound catheters. Background Technology

[0002] In minimally invasive cardiac surgery, the treatment of pericardial effusion requires interventional drainage using a puncture needle. Due to the complex anatomical structures surrounding the heart, insufficient puncture precision may damage myocardial tissue or adjacent blood vessels, leading not only to treatment failure but also potentially causing serious complications such as cardiac tamponade and arrhythmias, directly threatening the patient's life.

[0003] Traditional procedures rely on manual positioning with the aid of a puncture frame, where the physician manually adjusts the puncture angle and depth based on subjective experience. This method has significant drawbacks: firstly, the quality of the procedure is highly dependent on the physician's spatial awareness and skill level, requiring extensive training to master, and exhibiting significant individual differences; secondly, the lack of real-time navigation and correction mechanisms during manual advancement makes it susceptible to interference from subtle hand tremors, tissue deformation, and other factors, increasing the risk of puncture path deviation, especially in cases of abnormal cardiac dynamics or fluid distribution.

[0004] Patent CN118383804A proposes a puncture positioning method based on magnetic navigation technology. Its core lies in achieving magnetic positioning by magnetizing the puncture needle and integrating multiple magnetic sensors inside the catheter probe. This technology utilizes magnetic sensors to collect the magnetic field information of the puncture needle, thereby calculating the spatial position of the puncture needle in real time and guiding it during puncture. However, practical applications face two major technical challenges: Firstly, the miniaturization requirements of medical probes conflict with the spatial layout needs of multiple sensors; the limited internal space not only restricts the density of magnetic sensors but also increases the structural complexity of the probe. Secondly, the physical characteristics of the puncture needle magnetization process directly affect positioning accuracy; insufficient uniformity of material magnetization can lead to magnetic field distortion, subsequently causing spatial positioning errors. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a magnetic positioning system for intracardiac ultrasound catheters.

[0006] A magnetic positioning system for intracardiac ultrasound catheters, which is equipped with a puncture needle, an ultrasound catheter and a robotic arm.

[0007] The puncture needle is located at the end of the robotic arm;

[0008] The ultrasonic catheter is an independent tubular device, with an ultrasonic device and a magnetic device embedded in its distal tube.

[0009] The robotic arm is equipped with the following three modules:

[0010] The signal acquisition module includes an external sensing device for acquiring positioning signals of the ultrasonic catheter magnetic device;

[0011] The position calculation module includes a processor and a memory storing a target positioning algorithm. It is used to calculate the real-time movement position of the ultrasonic catheter based on the positioning signal using the target positioning algorithm. The position calculation module is signal-connected to the signal acquisition module.

[0012] The catheter tracking module includes a PID control chip, which controls the robotic arm to track the ultrasound catheter in real time according to the real-time movement position until the ultrasound catheter reaches the target position to be punctured. The catheter tracking module is signal-connected to the position calculation module.

[0013] Preferably, the puncture needle is a titanium alloy puncture needle with a diameter of 2.4 mm and a length of 60 mm.

[0014] Preferably, the external sensing device is located at the end of the robotic arm, the puncture needle is installed in the center of the external sensing device, and the puncture needle and the external sensing device are rigidly connected.

[0015] Preferably, the external sensing device is a magnetic sensor array with an adjacent sensor spacing of 40 mm and a number of sensors of no less than 5.

[0016] Preferably, the ultrasonic device is an ultrasonic transducer used to detect the target location that needs to be punctured.

[0017] Preferably, the magnetic device is a permanent magnet used to mark the real-time position of the ultrasonic catheter.

[0018] Preferably, the signal connection is a shielded twisted pair or coaxial cable for data transmission.

[0019] The beneficial effects of this utility model are as follows:

[0020] 1. This utility model integrates a magnetic device inside an ultrasonic catheter and a sensor device at the end of a robotic arm. The magnetic device is a permanent magnet, and the sensor device is a magnetic sensor array. Compared with magnetizing the puncture needle and integrating the sensor into the ultrasonic catheter, the system structure is simpler. Furthermore, the permanent magnet can provide a more stable magnetic field signal, and the sensor array can accommodate more sensors, thus ensuring better positioning accuracy.

[0021] 2. In the positioning process, this utility model utilizes the real-time position of the robotic arm and the current position of the ultrasonic catheter, enabling real-time navigation and correction. Compared to relying solely on manual judgment, this reduces the risk of deviation and further improves positioning accuracy. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this utility model, the following description of the relevant technical solutions of the embodiments of this utility model is provided in the accompanying drawings. It should be understood that the drawings described below are only for the purpose of clearly illustrating some embodiments of the technical solutions of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0023] Figure 1 This is a schematic diagram of the structural composition of the intracardiac ultrasound catheter magnetic positioning system provided in this embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram showing the positional relationship between the ultrasonic catheter and the sensor array provided in this embodiment of the present invention;

[0025] Figure 3 This is a flowchart illustrating a method of using the intracardiac ultrasound catheter magnetic positioning system provided by an embodiment of this utility model.

[0026] Explanation of reference numerals in the attached figures: 1-ultrasound catheter; 2-puncture needle; 3-magnetic sensor array; 4-robotic arm; 5-ultrasound device; 6-magnetic device. Detailed Implementation

[0027] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0028] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0029] This utility model embodiment provides a magnetic positioning system for intracardiac ultrasound catheters, the structural composition of which is as follows: Figure 1 As shown, it includes: a robotic arm 4, a puncture needle 2, and an ultrasonic catheter 1. The puncture needle 2 is located at the end of the robotic arm 4, and there is also a magnetic sensor array 3 at the end of the robotic arm 4. The puncture needle 2 is installed in the center of the magnetic sensor array 3, and the puncture needle 2 and the magnetic sensor array 3 are rigidly connected.

[0030] In this embodiment of the invention, the ultrasonic catheter 1 includes an ultrasonic device 5 and a magnetic device 6. The ultrasonic device 5 is used to detect the target location to be punctured, and the magnetic device 6 is used to mark the real-time position of the ultrasonic catheter 1. The magnetic sensor array 3 is used to locate the catheter by collecting the magnetic data of the magnetic device 6. The positional relationship between the ultrasonic catheter 1 and the sensor array 3 is as follows: Figure 2 As shown.

[0031] In this embodiment of the invention, the robotic arm 4 is provided with the following three modules: a signal acquisition module, including an external sensing device, for acquiring the positioning signal of the ultrasonic catheter; a position calculation module, including a processor and a memory storing a target positioning algorithm, for calculating the real-time position of the ultrasonic catheter based on the positioning signal using the target positioning algorithm, the position calculation module being signal-connected to the signal acquisition module; and a catheter tracking module, including a PID control chip, for controlling the robotic arm to track the ultrasonic catheter in real time based on the real-time position until the ultrasonic catheter reaches the target position to be punctured, the catheter tracking module being signal-connected to the position calculation module.

[0032] Specifically, the magnetic sensor array 3 adopts a 5*5 array distribution, with a total of 25 triaxial magnetic sensors, each measuring 2mm×2mm×1mm, and the spacing between the sensors is 40mm. A titanium alloy puncture needle 2 with a diameter of 2.4mm and a length of 60mm is mounted in the center of the magnetic sensor array 3. The puncture needle 2 is fixed to the center of the magnetic sensor array 3 by a rigid connector, perpendicular to the array plane. The connector is made of non-magnetic titanium alloy to avoid magnetic field interference. The composite of the magnetic sensor array 3 and the puncture needle 2 is mounted at the end of the four-axis controlled robotic arm 4, and the mechanical and electrical connections are achieved through a customized fixture.

[0033] Based on this, the doctor uses the ultrasound catheter 1 to locate the puncture site in real time. During this process, the magnetic sensor array 3 identifies the magnetic signal of the magnetic device 6, and the real-time movement position of the ultrasound catheter 1 can be obtained using the target positioning algorithm.

[0034] In this embodiment of the invention, the target localization algorithm employs the Levenberg-Marquardt algorithm. The magnetic field strength decreases cubically with distance, resulting in a highly nonlinear relationship between the target position and sensor data. The Levenberg-Marquardt algorithm effectively solves the nonlinear least squares problem by dynamically adjusting the damping factor and adaptively switching between gradient descent and Gauss-Newton methods, achieving sub-millimeter-level positioning accuracy. By setting the initial damping factor and the maximum number of iterations, the Levenberg-Marquardt algorithm converges to the target position on average within 15–20 iterations while maintaining accuracy, with a single solution time of <2ms, meeting the real-time tracking requirements of robotic arms.

[0035] In other implementations, the target localization algorithm can retain the Levenberg-Marquardt algorithm while introducing an unscented Kalman filter (UKF), employing a hybrid LM+UKF architecture. This hybrid architecture, through the synergy of nonlinear filtering and nonlinear optimization, utilizes the robotic arm's motion model and historical data to predict the magnetic source position, addressing the tracking delay caused by motion. Local optimization based on the UKF predictions eliminates model linearization errors, improving sub-millimeter-level positioning accuracy and achieving high-precision localization and tracking of magnetic targets in dynamic environments. By integrating the advantages of nonlinear filtering and optimization algorithms, the LM+UKF hybrid architecture achieves a good balance between dynamic accuracy, noise resistance, and computational efficiency, improving accuracy by 30%–50% compared to pure LM.

[0036] Furthermore, the control of robotic arm 4 employs a dual-loop PID strategy. When the processor calculates the real-time position of the ultrasonic catheter based on the target positioning algorithm, the outer loop PID immediately converts the deviation of the real-time position into joint torque commands, which are then transmitted to the inner loop PID. The inner loop PID directly drives the motor, precisely adjusting the width and frequency of the voltage pulses by sampling the motor current at high frequency to ensure that the torque output by the motor matches the commands from the outer loop. This entire process repeats continuously; the outer loop updates the pose correction every 2ms, while the inner loop fine-tunes the current at five times the speed. This allows the robotic arm to track the ultrasonic catheter in real time until it reaches the target position. The dual-loop PID, through the coordinated operation of the inner and outer loops, enables rapid response of the robotic arm and high-precision tracking of the ultrasonic catheter.

[0037] In this embodiment of the invention, the signal transmission method between the intracardiac ultrasound catheter magnetic positioning system primarily uses wired connections, supplemented by wireless connections. The data transmission between the signal acquisition module, position calculation module, and catheter tracking module employs shielded twisted-pair or coaxial cables, which provides strong resistance to electromagnetic interference and low latency, ensuring real-time data transmission during the positioning process. Monitoring of the robotic arm's status, such as vibration, utilizes low-power Bluetooth, allowing for remote monitoring of the robotic arm's condition and preventing instability from affecting the puncture procedure.

[0038] This utility model embodiment provides a method for using an intracardiac ultrasound catheter magnetic positioning system, the method flow is as follows: Figure 3 As shown, it includes:

[0039] Doctors use ultrasound catheters and ultrasound devices to locate the target site for puncture.

[0040] The robotic arm's external sensing device collects positioning signals from the ultrasonic catheter's magnetic device;

[0041] Based on the positioning signal, the processor calculates the real-time movement position of the ultrasonic catheter using a target positioning algorithm;

[0042] Based on the real-time movement position, the PID controller controls the robotic arm to track the ultrasound catheter in real time outside the body until the ultrasound catheter reaches the target position that needs to be punctured.

[0043] The doctor performs the puncture at the target location.

[0044] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to the embodiments of the present invention without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An intracardiac ultrasound catheter magnetic positioning system, comprising: The application relates to a puncture needle, an ultrasonic catheter and a mechanical arm. The puncture needle is located at the end of the mechanical arm. The ultrasonic catheter is an independent tubular device, and an ultrasonic device and a magnetic device are embedded in the distal end of the catheter. The mechanical arm is provided with the following three modules: A signal acquisition module, which comprises an extracorporeal sensing device and is used for acquiring a positioning signal of the magnetic device of the ultrasonic catheter. A position calculation module, which comprises a processor and a memory storing a target positioning algorithm, and is used for calculating the real-time moving position of the ultrasonic catheter through the target positioning algorithm according to the positioning signal; the position calculation module is in signal connection with the signal acquisition module. A catheter tracking module, which comprises a PID control chip and is used for controlling the mechanical arm to track the ultrasonic catheter in real time outside the body according to the real-time moving position until the ultrasonic catheter reaches a target position needing puncture; the catheter tracking module is in signal connection with the position calculation module.

2. A magnetic positioning system for an intracardiac ultrasound catheter according to claim 1, characterized in that The puncture needle is a titanium alloy puncture needle with a diameter of 2.4 mm and a length of 60 mm.

3. The magnetic positioning system for intracardiac ultrasound catheter of claim 1, wherein, The extracorporeal sensing device is located at the end of the mechanical arm, the puncture needle is installed at the center of the extracorporeal sensing device, and the puncture needle and the extracorporeal sensing device are rigidly connected.

4. A magnetic positioning system for an intracardiac ultrasound catheter according to claim 3, wherein, The extracorporeal sensing device is a magnetic sensor array, the spacing between adjacent sensors is 40 mm, and the number of sensors is not less than 5.

5. The intracardiac ultrasound catheter magnetic positioning system of claim 1, wherein, The ultrasonic device is an ultrasonic transducer used for detecting a target position needing puncture.

6. The intracardiac ultrasound catheter magnetic positioning system of claim 1, wherein, The magnetic device is a permanent magnet used for marking the real-time position of the ultrasonic catheter.

7. The intracardiac ultrasound catheter magnetic positioning system of claim 1, wherein, The signal connection is shielded twisted pair or coaxial cable transmission data.

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