A thermal fragmentation ablation probe system and method of controlling the same

Abstract

The application belongs to the technical field of medical apparatus and discloses a thermal crushing ablation probe system and a control method thereof. The system mainly comprises a control device, a direct current power supply module, a voltage boosting and reducing module, a modulated square wave generating module, a radio frequency generating module, a cooling control module, a data acquisition module and a probe. The probe is provided with a temperature sensor, which can collect tissue temperature in real time during treatment. The control device is electrically connected with the voltage boosting and reducing module, and can adjust the output voltage in real time, accurately control the radio frequency energy output by the probe, regulate and control the ablation tissue temperature and change the thermal physical properties of tissue cells, adjust the voltage peak value of the modulated square wave generating module, and make the tissue cells realize crushing under the synergistic effect of multiple physical fields. The control device dynamically regulates and controls the radio frequency energy and the pulse voltage energy according to the collected parameters such as tissue temperature, tissue impedance, pulse voltage and high-frequency current field power, so as to realize accurate and controllable tissue thermal crushing ablation.

Description

Technical Field

[0001] This invention relates to the field of biomedical engineering, and in particular to a thermal fragmentation and ablation probe technology. Background Technology

[0002] The incidence of malignant tumors, atherosclerosis, arrhythmia, benign tissue hyperplasia, and arteriovenous malformations is rising year by year, posing an increasing threat to human physical and mental health. While traditional treatment methods (such as surgery, radiotherapy, and chemotherapy) are becoming increasingly mature in clinical application, they inevitably cause significant trauma to normal tissue functions, and there is still room for improvement in treatment success rates. With the continuous advancement of science and technology, especially the rapid development of medical imaging technologies (such as magnetic resonance imaging (MRI), computed tomography (CT), and ultrasound imaging), minimally invasive surgical treatments have made significant progress. Due to their advantages of less trauma and faster recovery, their application in clinical treatment is becoming increasingly widespread. However, existing minimally invasive treatment methods still have their limitations; they cannot achieve precise targeted treatment of lesions, cannot fully improve cure rates, and cannot effectively protect normal tissues from damage. Radiofrequency ablation (RFA) technology uses a radiofrequency current field to heat and ablate lesions. Compared to microwave ablation and laser ablation, it has significant advantages such as low cost and ease of operation control, and has been widely used in the clinical treatment of diseases such as atherosclerosis, tumors, and arrhythmias. However, current RFA treatments on the market can only achieve "burning and inactivation" of lesions, easily damaging surrounding normal tissues, and have a high recurrence rate after treatment, making it difficult to achieve the clinical goal of one-time treatment and long-term effectiveness. Furthermore, its ablation effect is greatly affected by the physical properties of the tissue. Microwave ablation technology is not limited by impedance when radiating in biological tissues, and has advantages such as rapid heating, wide thermal field coverage, strong resistance to heat sink effect, and large single-needle ablation area. However, it has the prominent drawback of poor controllability of the ablation process. Irreversible electroporation (IRE) is a technique based on high-voltage short pulses. Electric field-based non-thermal physical ablation technology has the advantages of precise ablation without thermal effects, protection of key tissue structures such as blood vessels and nerves, clear ablation boundaries, and no interference from heat sink effects. However, it is prone to inducing muscle contraction during the ablation process, requiring deep anesthesia for the patient. In addition, the electric field distribution is greatly affected by the position of the puncture needle, which can easily lead to incomplete ablation, thus limiting its applicability. Cryoablation technology, on the other hand, has advantages such as clear ablation boundaries, low patient pain, and minimal damage to surrounding normal tissues. However, it has disadvantages such as slower ablation speed, limited ablation range, and higher treatment costs. Therefore, existing minimally invasive ablation techniques struggle to simultaneously achieve the following objectives: first, to efficiently disrupt cell membranes by modulating their mechanical properties through thermal effects followed by pulsed electric fields; and second, to effectively expand the range of radiofrequency ablation while ensuring a stable and controllable ablation area. To address these technical challenges, this paper proposes a novel thermal disruption ablation probe system. Summary of the Invention

[0003] To address the limitations of existing minimally invasive treatment methods, this invention proposes a thermal disruption ablation probe system and its control method. By precisely controlling different ablation signals, the thermal stress of the cell membrane is altered through thermal action, and then a modulated square wave is applied to induce cell disruption, thereby changing the electrical properties of the tissue. Ultimately, this significantly expands the ablation range while substantially improving the controllability of the ablation process.

[0004] To solve the above-mentioned technical problems, the present invention mainly adopts the following technical solutions: A thermal ablation probe system includes: a power supply, a step-up / step-down module, a radio frequency generation module, a modulated square wave generation module, a data acquisition module, a control device, and a probe; The probe integrates a temperature sensor for real-time acquisition of the temperature of the target tissue and transmission to the data acquisition module; The input terminal of the buck-boost module is connected to the power supply, the output terminal is connected to the radio frequency generation module and the modulation square wave generation module respectively, and the control terminal is connected to the control device, which is used to output a variable DC voltage under the control of the control device. The radio frequency generation module is used to output radio frequency energy to the probe to heat the target tissue; The modulated square wave generation module is used to output a pulsed square wave electric field with adjustable pulse width, number of pulses and peak voltage to the probe to break the target tissue cells; The control device is used to: control the radio frequency generation module to heat the target tissue to a first set temperature to change its thermophysical properties; control the modulation square wave generation module to output a pulsed square wave electric field to break the cells according to the tissue impedance value collected by the data acquisition module; and control the radio frequency generation module to reheat the target tissue to a second set temperature to complete thermal ablation.

[0005] Furthermore, the buck-boost module adopts a high-frequency switching power supply topology, and its output voltage is continuously adjustable within the range of 0-2KV.

[0006] Furthermore, a thermocouple for measuring tissue temperature is set at a specific position on the tip of the probe. The thermocouple is used to monitor the temperature change during the tissue thermal disruption process in real time and to feed the temperature data back to the data acquisition module.

[0007] Furthermore, the probes include two types: multi-stage flexible catheter probes and bipolar percutaneous puncture probes.

[0008] Furthermore, the multi-stage flexible catheter probe integrates multiple independently controllable and selectable annular metal electrodes on its catheter, and each annular metal electrode is connected to the output terminals of the modulation square wave generation module and the radio frequency generation module through microguidewires.

[0009] Furthermore, the bipolar percutaneous puncture probe includes a tip temperature sensor, a water-cooled circulating microchannel, a high-voltage insulating layer, and an electrode metal tube. The water-cooled circulating microchannel is connected to a cooling system, and the electrode metal tube is connected to a modulation square wave generation module and a radio frequency generation module, respectively.

[0010] Furthermore, the probe can simultaneously transmit cooling energy from the cooling system, radio frequency energy from the radio frequency generation module, and modulated square wave energy from the modulated square wave generation module.

[0011] Furthermore, the modulated square wave generation module can output positive and negative pulse square wave electric fields, or it can output a positive pulse square wave electric field alone, and the rise time of its output pulse is less than 10 ns.

[0012] Furthermore, the modulated square wave generation module also includes an energy storage circuit, which is used to meet the instantaneous high current demand when the square wave electric field is output, and to ensure the stable output of the square wave electric field energy.

[0013] Correspondingly, the present invention also provides a thermal breakup and ablation control method, applied to the above-mentioned thermal breakup and ablation probe system, comprising the following steps: S1: The radio frequency generation module is started with low power to output radio frequency energy. At the same time, the temperature of the target tissue is collected in real time by the temperature sensor inside the probe. The control device adjusts the output of radio frequency energy according to the collected temperature data, so that the temperature of the target tissue at the probe tip rises to the set temperature T1 at a constant heating rate and is maintained at this temperature for time t1, so as to change the thermophysical properties of the cell. S2: Detect the tissue impedance after heating pretreatment, adjust the output parameters of the modulation square wave according to the detected impedance value, then turn off the radio frequency generation module, turn on the modulation square wave generation module to output the modulation square wave electric field, and turn off the modulation square wave generation module after a duration of t2; turn on the radio frequency generation module again and output the radio frequency signal with low power to detect the tissue impedance characteristics after the modulation square wave is applied. S3: Analyze the changes in tissue electrical impedance during the action of S1 and S2, and repeat the control process of S1 and S2 based on the changes; S4: Using the temperature collected by the temperature sensor at the probe tip as a reference, the control device regulates the radio frequency generation module to output radio frequency energy at a constant heating rate, heats the target tissue to the set temperature T2, and maintains the temperature for the set time to complete the thermal ablation process.

[0014] Compared with the prior art, the present invention has the following beneficial technical effects: By precisely controlling the radio frequency output power applied to the probe in real time, the heating process and temperature of the ablated tissue can be precisely controlled. This allows the thermal properties of the tissue cell membrane to be altered first, reducing the mechanical stability of the cell membrane and creating favorable conditions for subsequent pulsed electric field disruption, thereby improving the efficiency and thoroughness of cell disruption.

[0015] After thermal pretreatment, a modulated square wave signal with a rising edge is applied, and the cell membrane, whose mechanical properties have been altered, is precisely broken using a pulsed electric field. After the cell membrane ruptures, the endoplasmic fluid flows out, causing a significant change in the electrical properties of the local tissue and enhancing the uniformity of tissue impedance. This improves the uniformity of the radiofrequency current field distribution in the tissue and enhances the effect of subsequent radiofrequency ablation.

[0016] The control device dynamically adjusts the output sequence and parameters of radiofrequency energy and pulsed electric field energy based on the real-time acquisition of tissue temperature, tissue impedance and other parameters by the data acquisition module. This achieves closed-loop coordinated control of thermal and electrical effects, making the ablation zone boundary clear, stable and controllable, and avoiding the problems of incomplete ablation or excessive burning caused by uneven tissue impedance in traditional radiofrequency ablation.

[0017] Because the uniformity of tissue impedance increases after cell disruption, the radiofrequency current field can penetrate more effectively into a larger area of ​​tissue to be ablated. At the same time, by regulating the radiofrequency heating process, the heat accumulation near the probe is reduced, and the radiofrequency energy is transferred to the distal tissue more efficiently, thereby increasing the volume of a single ablation.

[0018] Compared with existing technologies such as radiofrequency ablation, cryoablation, and steep pulse ablation, the thermal fragmentation ablation probe system of this invention not only has a controllable ablation range and a larger achievable ablation volume, but also has a relatively simple system structure and an easy-to-implement control method, reducing equipment complexity and operational difficulty while ensuring treatment effectiveness. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a probe system structure according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a bipolar percutaneous puncture probe structure in one embodiment of the present invention; Figure 3 This is a schematic diagram of a flexible probe structure in one embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of a modulation square wave generation module in one embodiment of the present invention.

[0020] The numbers in the diagram are as follows: 1-Power supply, 2-Probe control system, 3-Probe, 21-Boost / buck module, 22-RF generator module, 23-Modulated square wave generator module, 24-Control device, 25-Cooling system, 26-Data acquisition module, 311-Thermocouple, 312-Probe electrode, 313-High voltage insulating coating, 314-Insulating layer, 315-Energy transmission line, 316-Cold medium inlet, 317-Cold medium outlet, 321-Flexible electrode, 322-Flexible conduit, 323-Flexible electrode transmission line, 324-Thermocouple, 231-Energy storage circuit, 232-Full-bridge switch circuit, 233-Optical isolation drive circuit, 234-Isolation output circuit, 235-Isolation sampling circuit, 236-Discharge circuit. Detailed Implementation

[0021] In the following description, many technical details are presented to help the reader better understand this application. However, those skilled in the art will understand that the technical solutions claimed in this application can be implemented even without these technical details and with various variations and modifications based on the following embodiments.

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0023] The first embodiment of this application relates to a thermal breakage probe system, the structure of which is as follows: Figure 1 As shown, it includes a thermal breakage probe 3, a power supply 1, a step-up / step-down module 21, an RF generation module 22, a modulated square wave generation module 23, a control device 24, a cooling system 25, and a data acquisition module 26.

[0024] Ground power supply 1 is a DC power module, electrically connected to the input of buck-boost module 21, converting it into a 0-2KV real-time adjustable output voltage. The control terminal of buck-boost module 21 is also electrically connected to control device 24. The output of buck-boost module 21 is electrically connected to radio frequency generation module 22 and modulation square wave generation module 23. Control device 24 sends control signals to adjust the output voltage of buck-boost module 21 in real time, thereby adjusting the peak value of square wave output of square wave module 23 and controlling the real-time output power of radio frequency generation module 22. Control device 24 is electrically connected to cooling system 25 to control the flow rate of cooling system 25 and precisely adjust the tissue heating temperature of radio frequency generation module 22. Control device 24 is electrically connected to data acquisition module 26 to collect tissue resistance, heating temperature, radio frequency power, etc. in real time during thermal ablation. Control device 24 feeds back the collected parameters to the control algorithm to adjust the output of radio frequency generation module 22 or modulation square wave generation module 23 in real time.

[0025] like Figure 2The diagram shows a percutaneous puncture probe structure in a thermal ablation probe, which includes a needle tip thermocouple 311, a thermal ablation electrode 312, a high-voltage insulation layer 313, an electrical insulation layer 314, an electrode signal transmission line 315, a cold medium inlet pipe 316, and a cold medium outlet 317. A tip thermocouple 311 is installed at a specific position on the probe tip for real-time feedback of tissue temperature. The thermocouple wire is connected to the interface of the thermal ablation probe system through a capillary metal tube. The thermal ablation electrode 312 adopts a design of two coaxial metal tubes, with a high-voltage resistant insulating coating 313 used for electrical isolation in between. In this embodiment, the high-voltage insulating layer uses a Teflon coating with a thickness of 0.02 mm. The outer layer of the thermal ablation electrode 312 uses an electrical insulating layer 314 to electrically isolate it from normal tissue. The coaxial tube of the thermal ablation electrode 312 and the electrode signal transmission line 315 are electrically connected to the thermal ablation probe system 2 for transmitting radiofrequency treatment energy and modulated square wave energy to the treated tissue. The cold medium inlet tube 316 adopts a capillary metal tube design. The cold circulation system 25 introduces the cold medium into the probe electrode ablation area through the cold medium inlet 316 for heat exchange, and then discharges it along the inner wall of the coaxial electrode tube through the cold medium outlet 317.

[0026] In this embodiment, the outer diameter of the percutaneous thermal ablation probe 31 is less than 1.5 mm, the metal tube of the thermocouple 311 is less than 0.3 mm, and the diameter of the cold medium inlet tube 316 is less than 0.5 mm.

[0027] The second embodiment of this application includes a flexible thermal fragmentation and ablation probe 32 that enters through a natural cavity, such as... Figure 3 As shown, the system includes a multi-level ablation electrode 321, a flexible polymer conduit 322, a flexible electrode transmission line 313, and a thermocouple 314. The multi-level ablation electrode 321 is embedded in the flexible polymer conduit 322 in a specific arrangement and is electrically connected to the flexible electrode transmission line 313. The other end of the flexible electrode transmission line 313 is connected to the ablation energy output end of the probe treatment system 2, so that the radiofrequency ablation energy and the modulated square wave energy are transmitted to the treatment tissue through the multi-level flexible electrode 321 for precise thermal ablation treatment.

[0028] In this embodiment, the transmission electrode adopts a multi-electrode design, which is beneficial to increase the degree of freedom of the catheter entering the cavity. At the same time, each electrode can be controlled independently, and the electrode can be selected according to the tissue to be ablated, so as to achieve conformal ablation.

[0029] The preferred embodiment of the modulation method generation module of this application is as follows: Figure 4As shown, the system includes an energy storage circuit 231, a full-bridge switch circuit 232, an isolated output circuit 234, an isolated sampling circuit 235, an optocoupler isolation driver 233, and a discharge circuit 236. The energy storage circuit 231 is electrically connected to the output of the buck-boost module 21 to store the energy output from the buck-boost module 21. The output of the energy storage circuit 231 is electrically connected to the full-bridge switch 232. By controlling the operation of the full-bridge switch circuit 232, the operating mode of the modulated square wave is controlled. The output of the energy storage circuit 231 is also electrically connected to the discharge circuit 236. When the system is powered off, the discharge circuit is automatically activated to discharge energy from the energy storage circuit 231, ensuring system safety. The control terminal of the full-bridge switching circuit 232 is electrically connected to the optocoupler isolation drive circuit 233. The input of the optocoupler isolation drive 233 is electrically connected to the control device 24. The control device 24 sends a modulated square wave control signal to the optocoupler isolation drive 233. After the signal is isolated and amplified, it drives the full-bridge switching circuit 232 to send a high-power modulated square wave signal, which is output to the modulated square wave isolation output circuit 234 and transmitted to the probe 3. At the same time, the isolation sampling circuit 235 samples the voltage and current of the modulated square wave output and transmits them to the control device 24 as a control feedback signal for precise thermal ablation.

[0030] The third embodiment of this application also includes a method for controlling a thermal ablation probe, which mainly includes the following steps: S1: The radio frequency generation module is started with low power to output radio frequency energy. At the same time, the temperature of the target tissue is collected in real time by the temperature sensor inside the probe. The control device adjusts the output of radio frequency energy according to the collected temperature data, so that the temperature of the target tissue at the probe tip rises to the set temperature T1 at a constant heating rate and is maintained at this temperature for t1 time, so as to change the thermophysical properties of the cell. S2: Detect the tissue impedance after heating pretreatment. Based on the detected impedance, adjust the output parameters of the modulation square wave, turn off the radio frequency energy output, switch to the modulation square wave output, and after a duration of t2, turn off the modulation square wave generation module and switch the radio frequency generation module to work. Use a low-power radio frequency signal to detect the impedance characteristics after the modulation square wave is applied. S3: Analyze the changes in tissue electrical impedance during the action of S1 and S2, and repeat the control process of S1 and S2 based on the changes.

[0031] In this embodiment, if the rate of change of impedance before and after S1 is lower than a preset first threshold such as 20%, it indicates that the heat pretreatment has not sufficiently changed the thermophysical properties of the cell, and S1 is automatically repeated until the rate of change of impedance reaches the threshold. If the impedance change rate before and after S2 is lower than the preset second threshold, such as 30%, it indicates that the cells are not sufficiently broken down. Then, the voltage amplitude, pulse width, or number of pulses of the modulated square wave is dynamically adjusted according to the current impedance value, and S2 is repeated until the impedance change rate reaches the threshold. Once the impedance change meets the threshold requirements, the repetition loop is exited, and S4 is executed.

[0032] S4: Using the temperature collected by the temperature sensor at the probe tip as a reference, the control device regulates the radio frequency generation module to output radio frequency energy at a constant heating rate, heats the target tissue to the set temperature T2, and maintains the temperature for the set time to complete the thermal ablation process.

Claims

1. A thermal fragmentation ablation probe system, comprising: The power supply (1), buck-boost module (21), RF generator module (22), modulated square wave generator module (23), data acquisition module (26), control device (24), and probe (3) are characterized in that: The probe (3) integrates a temperature sensor (311) for real-time acquisition of the temperature of the target tissue and transmission to the data acquisition module (26). The input terminal of the step-up / step-down module (21) is connected to the power supply (1), the output terminal is connected to the radio frequency generation module (22) and the modulation square wave generation module (23) respectively, and the control terminal is connected to the control device (24) for outputting a variable DC voltage under the regulation of the control device (24). The radio frequency generation module (22) is used to output radio frequency energy to the probe (3) to heat the target tissue; The modulated square wave generation module (23) is used to output a pulsed square wave electric field with adjustable pulse width, number and peak voltage to the probe (3) to break the target tissue cells; The control device (24) is used to: control the radio frequency generation module (22) to heat the target tissue to a first set temperature to change its thermophysical properties; control the modulation square wave generation module (23) to output a pulsed square wave electric field to break the cells according to the tissue impedance value collected by the data acquisition module (26); and control the radio frequency generation module (22) to heat the target tissue again to a second set temperature to complete thermal ablation.

2. The thermal fragmentation and ablation probe system according to claim 1, characterized in that, The step-up / step-down module (21) adopts a high-frequency switching power supply topology, and its output voltage is continuously adjustable in the range of 0-2KV.

3. The thermal fragmentation and ablation probe system according to claim 1, characterized in that, The probe (3) has a thermocouple (311) at a specific position on its tip for measuring tissue temperature. The thermocouple (311) is used to monitor the temperature change during the tissue thermal breakdown process in real time and to feed the temperature data back to the data acquisition module (26).

4. The thermal fragmentation and ablation probe system according to claim 3, characterized in that, The probe (3) includes two types: a multi-level flexible catheter probe (32) and a bipolar percutaneous puncture probe (31).

5. The thermal fragmentation and ablation probe system according to claim 4, characterized in that, The multi-level flexible catheter probe (32) integrates multiple independently controllable and selectable annular metal electrodes (321) on the catheter. Each annular metal electrode (321) is connected to the output end of the modulation square wave generation module (23) and the radio frequency generation module (22) through a microguidewire.

6. The thermal fragmentation ablation probe system according to claim 4, characterized in that, The bipolar percutaneous puncture probe (31) includes a tip temperature sensor (311), a water-cooled circulation microchannel, a high-voltage insulating layer (313), and an electrode metal tube (312). The water-cooled circulation microchannel is connected to the cooling system (25), and the electrode metal tube (312) is connected to the modulation square wave generation module (23) and the radio frequency generation module (22), respectively.

7. The thermal fragmentation ablation probe system according to claim 1, characterized in that, The probe (3) can simultaneously transmit cooling energy from the cooling system (25), radio frequency energy from the radio frequency generation module (22), and modulated square wave energy from the modulation square wave generation module (23).

8. The thermal fragmentation ablation probe system according to claim 1, characterized in that, The modulated square wave generation module (23) can output positive and negative pulse square wave electric fields, or it can output positive pulse square wave electric fields alone, and the rise time of its output pulse is less than 10ns.

9. The thermal fragmentation and ablation probe system according to claim 1, characterized in that, The modulated square wave generating module (23) also includes an energy storage circuit (231), which is used to meet the instantaneous large current demand when the square wave electric field is output, and to ensure the stable output of the square wave electric field energy.

10. A method for controlling thermal fragmentation and ablation, applied to the thermal fragmentation and ablation probe system according to any one of claims 1 to 9, characterized in that, Includes the following steps: S1: The radio frequency generation module is started with low power to output radio frequency energy. At the same time, the temperature of the target tissue is collected in real time by the temperature sensor inside the probe. The control device adjusts the output of radio frequency energy according to the collected temperature data, so that the temperature of the target tissue at the probe tip rises to the set temperature T1 at a constant heating rate and is maintained at this temperature for time t1, so as to change the thermophysical properties of the cell. S2: Detect the tissue impedance after heating pretreatment, adjust the output parameters of the modulation square wave according to the detected impedance value, then turn off the radio frequency generation module, turn on the modulation square wave generation module to output the modulation square wave electric field, and turn off the modulation square wave generation module after a duration of t2; turn on the radio frequency generation module again and output the radio frequency signal with low power to detect the tissue impedance characteristics after the modulation square wave is applied. S3: Analyze the changes in tissue electrical impedance during the action of S1 and S2, and repeat the control process of S1 and S2 based on the changes; S4: Using the temperature collected by the temperature sensor at the probe tip as a reference, the control device regulates the radio frequency generation module to output radio frequency energy at a constant heating rate, heats the target tissue to the set temperature T2, and maintains the temperature for the set time to complete the thermal ablation process.

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