阅读说明：本技术 一种可增加消融面积及消融方向可控的脉冲消融方法和液态电极 (Pulse ablation method capable of increasing ablation area and controlling ablation direction and liquid electrode ) 是由 蓝闽波 潘巨敏 赵红莉 钱程 董鹏程 程雅欣 于 2021-07-28 设计创作，主要内容包括：本发明涉及一种可增加消融面积及消融方向可控的脉冲消融方法和液态电极,包括液态电极的结构,液体的种类、浓度。该方法通过向传统的脉冲消融电极的预定位置外注入一定量的导电溶液以增加消融电极的面积。在不改变原有电极尺寸的前提下,通过注入导电溶液增加电极的有效消融尺寸来扩大消融的面积,电极所能增加的尺寸取决于导电溶液所能注入的体积量；或在较小的电极尺寸下,通过注入导电溶液使电极的有效消融尺寸增加到临床常用的尺寸,电极尺寸可增大2-10倍,并且满足与传统电极相当的消融效果。另外通过控制液体在预定目标内的分布,也可以控制消融的方向。(The invention relates to a pulse ablation method capable of increasing ablation area and controlling ablation direction and a liquid electrode. The method increases the area of the ablation electrode by injecting a quantity of conductive solution outside of the intended location of a conventional pulsed ablation electrode. Under the premise of not changing the size of the original electrode, the effective ablation size of the electrode is increased by injecting the conductive solution to enlarge the ablation area, and the size which can be increased by the electrode depends on the volume amount which can be injected by the conductive solution; or at a smaller electrode size, the effective ablation size of the electrode is increased to a clinically common size by injecting a conductive solution, the electrode size can be increased by 2-10 times, and the ablation effect equivalent to that of the conventional electrode is satisfied. Additionally, by controlling the distribution of the liquid within the intended target, the direction of ablation can also be controlled.)

1. A pulse ablation method capable of increasing ablation area and controlling ablation direction is characterized in that the ablation area of an original electrode can be increased or the size of the electrode can be reduced, and the method specifically comprises the following steps:

increasing the area of the ablation electrode by injecting a certain amount of conductive solution outside the preset position of the traditional pulse ablation electrode; under the premise of not changing the size of the original electrode, the effective ablation size of the electrode is increased by injecting the conductive solution to enlarge the ablation area, and the size which can be increased by the electrode depends on the volume amount which can be injected by the conductive solution; or under the condition of smaller electrode size, the effective ablation size of the electrode is increased to the size commonly used in clinic by injecting the conductive solution, the size of the electrode can be increased by 2-10 times, the ablation effect equivalent to that of the traditional electrode is met, and the puncture wound is reduced; by controlling the distribution of the liquid within the intended target, the direction of ablation can also be controlled.

2. A liquid electrode, comprising:

metal electrode needles, conductive liquid and injectors used in pairs;

the metal electrode needle comprises a metal electrode needle front end, a metal electrode needle middle section and a metal electrode needle tail end;

the front end of the metal electrode needle is an exposed end, namely a pulse voltage output end, the surface of the electrode needle at the front end of the metal electrode needle is exposed and provided with small holes, a film material which can be expanded and has an open pore structure is arranged in the opening direction of the small holes, when conductive liquid is injected into the metal electrode needle, the film material can be expanded, and the conductive liquid penetrates through the open pores on the film material to form a conductive layer on the outer surface of the film; the middle section of the metal electrode needle is wrapped by an insulating material;

the tail end of the metal electrode needle is divided into an injector connecting end and a pulse generator connecting end, and the injector is connected with the metal electrode needle through the injector connecting end;

the syringe is of a cylindrical structure, one end of the syringe is matched with the metal electrode needle through a thread structure, and the conductive liquid is pushed into the metal electrode needle through the syringe; the surface of the injector is also provided with a calibration system.

3. The liquid electrode according to claim 2, wherein the metal material of the metal electrode needle is selected from the group consisting of gold, silver, copper, platinum, and zinc; the insulating material can be polyurethane, polytetrafluoroethylene, polyethylene, polyvinyl chloride, polymethyl methacrylate and other plastic materials; the film material can be thermoplastic materials such as polyethylene glycol terephthalate, cross-linked polyethylene, nylon and the like; the material of the injector can adopt non-conductive materials such as glass or plastic.

4. The liquid electrode according to claim 2, wherein the diameter of the metal electrode needle is variable, and the inside of the metal electrode needle is a hollow structure for delivering or sucking the conductive solution to the predetermined tissue; and a scale system can be arranged at the middle section of the metal electrode needle so as to accurately determine the puncture depth.

5. The liquid electrode as claimed in claim 2, wherein the front end surface of the metal electrode needle is of a non-sealed structure, and the exposed length is variable; the front metal surface is distributed with directional small holes with certain shapes, the position of the hole is set according to the actual required direction position of the membrane expansion, and the hole is covered by the membrane material.

6. The liquid electrode of claim 2, wherein the membrane material is configured to resemble a balloon structure and is expandable to a predetermined shape upon the introduction of a conductive liquid; the distribution position, size and shape of the membrane material can be adjusted to control the distribution of the liquid within the predetermined target, and thus the area and direction of ablation.

7. The liquid electrode according to claim 2, wherein the conductive liquid is composed of a liquid having good conductivity and excellent biocompatibility; the conductive liquid is preferably sodium chloride, calcium chloride solution or liquid metal with better conductivity and the like; the concentration of the conductive solution can be varied and adjusted from pure water to a saturated solution.

8. The liquid electrode of claim 2, wherein the liquid electrode comprises at least one electrode that is energized and at least one electrode that is grounded, wherein the electrode is capable of withstanding a pulse voltage of 3000 to 4000 volts, a pulse width of 0.01 to 100 μ s, and a pulse voltage of 1kHZ to 1MHZ when energized.

9. The liquid electrode according to claim 2, wherein the electrode metal electrode needle can be replaced by a medical flexible catheter, and can be applied to minimally invasive ablation of human body lumen tissue.

10. The method for pulse ablation with increased ablation area and controllable ablation direction according to claim 1, wherein the ablation area of the original electrode can be increased or the size of the electrode can be reduced, and the method comprises the following steps:

applying the liquid electrode of any one of claims 2-9, increasing the area of the ablation electrode by injecting a quantity of conductive solution outside the predetermined location of the liquid electrode; under the premise of not changing the size of the original electrode, the effective ablation size of the electrode is increased by injecting the conductive solution to enlarge the ablation area, and the size which can be increased by the electrode depends on the volume amount which can be injected by the conductive solution; or under the condition of smaller electrode size, the effective ablation size of the electrode is increased to the size commonly used in clinic by injecting the conductive solution, the size of the electrode can be increased by 2-10 times, the ablation effect equivalent to that of the traditional electrode is met, and the puncture wound is reduced; by controlling the distribution of the liquid within the intended target, the direction of ablation can also be controlled.

Technical Field

The application relates to a pulse ablation method and a liquid electrode, which can increase ablation area and control ablation direction. More particularly, the present application relates to an electrode for generating irreversible electroporation on cells of a biological tissue or inducing apoptosis of the biological tissue, and a method for enhancing ablation area and ablation direction control using a conductive solution.

Background

Non-infectious diseases such as cardiovascular diseases, cancer and chronic respiratory diseases are the main causes of morbidity and mortality in low-income countries. The world health organization indicates that more than 3600 thousands of people die of non-infectious diseases (accounting for 63 percent of the total death) every year in the global action plan for preventing and controlling the non-infectious diseases from 2013 to 2020. Of these, over 1400 million people are between the ages of 30 and 70, with low-to-mid income countries accounting for 86% of deaths. This will accumulate in the next 15 years resulting in an economic loss of 7 trillion dollars, putting millions into poverty.

In addition to active prevention of these diseases, the development of more desirable therapeutic approaches is of great importance to the economic and health levels of humans. The local physical ablation technology is developed under the background, and compared with the traditional treatment method, the physical ablation has the advantages of no chemical toxicity, minimal invasion, few complications and the like, so the local physical ablation technology is widely applied to clinical treatment of diseases such as tumors, cardiovascular diseases (atrial fibrillation), chronic respiratory diseases (chronic obstructive pulmonary disease) and the like. Through decades of development, various treatment technologies such as Radio Frequency (RFA), microwave, high-concentration ultrasound, laser, cryoablation and the like are derived from physical ablation. These treatments destroy the cellular structure and thus kill the tissue by changing the temperature at the target area. However, the effect of "heat sink" during ablation (heat loss due to blood perfusion) can affect the effectiveness of the treatment. Meanwhile, they are not selective, and may damage the vital organs, large vessels and nerves of the adjacent parts during treatment, which limits the application range of the physical ablation technology to a certain extent. Therefore, an emerging non-thermally selective physical ablation technique, i.e., Irreversible electroporation (IRE) ablation, has attracted attention.

The IRE ablation technique is widely used for the research and clinical treatment of tumor ablation, especially for the tumor that can not be ablated and is adjacent to the heat-sensitive organs such as blood vessels, nerves, bile ducts, etc., by applying a Pulsed Electric Field (PEF) to target cells to cause irreversible perforation of the cells and further induce cell necrosis or apoptosis. In recent years, IRE is also increasingly applied to ablation treatment of cardiovascular and other lumen diseases, and researches show that IRE has a good pulmonary vein continuous isolation effect, so that the incidence rate of some complications is remarkably reduced. As a selective physical ablation technology, IRE can protect important structures such as nerves, blood vessels and the like, and has the advantages of clear boundary of an ablation area, short treatment time, quick recovery after treatment and the like. In addition, IRE is monitored in real time by medical imaging technologies such as computed tomography, ultrasonic waves and nuclear magnetic resonance in the treatment process, the shape, the volume and the position of an ablation part can be determined, and the damage range can be effectively controlled. Accordingly, IRE ablation techniques are considered to have the potential to replace traditional thermal ablation techniques.

However, IRE ablation techniques also present some issues that need to be addressed, such as:

only suitable for the treatment of smaller tumors (less than 3cm), the treatment of larger tumors (2.5 x 2.5cm) requires about 6 treatment electrodes to be inserted to cover the ablation area, which increases much extra pain for the patient. In addition, patients experience varying degrees of adverse reactions such as arrhythmias, pneumothorax, elevated blood pressure, acid-base balance disorders, and muscle contractions in a number of clinical trials. These adverse reactions occur in part due to punctures or trauma during treatment.

Therefore, increasing the area of ablation, reducing trauma from the puncture, would be beneficial in reducing the adverse effects of treatment on the patient and greatly increase the range of application of IRE electrodes.

According to different electrode structures, the current IRE electrode mainly comprises a flat plate electrode, a clamp electrode, a negative pressure electrode, a non-invasive needle electrode, a catheter electrode, a needle electrode and the like. The electrodes generally comprise at least a positive electrode and a negative electrode, and the electrodes form an electric field loop after contacting with tissues. The selection, arrangement and number of the electrodes directly influence the size and distribution of the ablation electric field, and are one of the important factors influencing the final effect of the IRE. CN106388933B discloses an IRE device with an electrode body that is needle-like and needs to penetrate tissue for use, using an insulating region to confine the electric field to reduce muscle contraction. Furthermore, injection of liquids into predetermined tissues is commonly used for electrotransfer of DNA or for electrochemical therapy, and CN1678369B discloses a reversible electroporation device and injection means for introducing substances into cells. CN105920724B discloses a liquid metal peritoneal perfusion and electrochemical treatment device, the power supply voltage used by the device is 2-10V, and the current is not more than 10 mA.

Disclosure of Invention

The invention aims to provide a pulse ablation method capable of increasing ablation area and controlling ablation direction and a liquid electrode designed by the method. A certain amount of conductive solution is wrapped at a preset position outside the original ablation electrode to form a novel liquid electrode with the size being amplified and the direction of an amplification area being controllable, and the novel liquid electrode is used for increasing the ablation area and controlling the ablation direction. This method can be used for all conventional electrode modifications. In addition, a needle-like liquid electrode is designed according to the method. The electrode comprises a positive electrode and a negative electrode, and the conductive liquid with certain concentration is injected into the preset area around the thin metal needle, so that puncture wound is reduced, the ablation area is increased, the size and the direction of the opening of the preset area can be changed to effectively select the preset area, and the controllability of the ablation direction is realized.

The technical scheme of the invention is as follows:

a pulse ablation method capable of increasing ablation area and controlling ablation direction can increase the ablation area of an original electrode or reduce the size of the electrode, and specifically comprises the following steps:

the area of the ablation electrode is increased by injecting a quantity of conductive solution outside the intended location of the conventional pulsed ablation electrode. Under the premise of not changing the size of the original electrode, the effective ablation size of the electrode is increased by injecting the conductive solution to enlarge the ablation area, and the size which can be increased by the electrode depends on the volume amount which can be injected by the conductive solution; or under the condition of smaller electrode size, the effective ablation size of the electrode is increased to the size commonly used in clinic by injecting the conductive solution, the size of the electrode can be increased by 2-10 times, the ablation effect equivalent to that of the traditional electrode is met, and the puncture wound is reduced. Additionally, by controlling the distribution of the liquid within the intended target, the direction of ablation can also be controlled.

The invention also provides a liquid electrode designed by the method, namely a liquid electrode for delivering electric pulses, which comprises the following components:

metal electrode needles, conductive liquid and injectors used in pairs;

the metal electrode needle is divided into a front end of the metal electrode needle, a middle section of the metal electrode needle and a tail end of the metal electrode needle; the front end is an exposed end, namely a pulse voltage output end, the surface of the electrode needle at the front end of the metal electrode needle is exposed and provided with small holes, and a film material which can be expanded and has a hole structure is arranged in the hole opening direction. And injecting conductive liquid into the metal electrode needle to open the membrane material, wherein the conductive liquid penetrates through the opening on the membrane material to form a conductive layer on the outer surface of the membrane. The middle section metal electrode needle is wrapped by insulating material, does not participate in the ablation process, can increase the puncture depth, is convenient for the handheld puncture of operator. The tail end of the needle is divided into an injector connecting end and a pulse generator connecting end, wherein the injector connecting end is a place where the metal electrode needle is connected with the injector; the pulse generator connecting end is a pulse voltage input end.

The conductive liquid is composed of a liquid having good conductivity and excellent biocompatibility. After the metal needle is inserted into the preset tissue, the conducting solution is delivered to the preset tissue through the hollow structure of the metal needle, and a certain space is expanded outside the metal needle to increase the ablation area and control the ablation direction.

The syringe is of a cylindrical structure, is similar to a medical syringe but does not have a needle head, the syringe is matched with the metal electrode needle through a thread structure, certain sealing performance is guaranteed, and the conductive liquid is pushed into the metal electrode needle through the syringe. The surface of the injector is provided with a scale system so as to accurately determine the volume of the conductive solution to be conveyed; the syringe tube body can adopt a certain fixing means (for example, two syringes are fixed together by a connecting device) to fix the electrode, so that the electrode cannot shift during puncture ablation.

According to the liquid electrode, further, the metal material of the metal electrode needle can be various conductive materials such as gold, silver, copper, platinum, zinc and the like; the insulating material can be polyurethane, polytetrafluoroethylene, polyethylene, polyvinyl chloride, polymethyl methacrylate and other plastic materials; the film material can be thermoplastic materials such as polyethylene glycol terephthalate, cross-linked polyethylene, nylon and the like; the material of the injector can adopt non-conductive materials such as glass or plastic.

The material of the injector can adopt non-conductive materials such as glass or plastic; the surface of the injector is provided with a calibration system so as to accurately determine the volume of the conductive solution to be delivered.

According to the liquid electrode, the diameter of the metal needle of the metal electrode needle is variable, and the interior of the metal electrode needle is of a hollow structure and is used for conveying or sucking a conductive solution to a preset tissue; the middle section of the metal electrode needle can be provided with a calibration system so as to accurately determine the puncture depth.

According to the liquid electrode, the surface of the front end of the metal electrode needle is a non-sealing structure, and the exposed length is variable. The front metal surface is distributed with directional small holes (the shape is not specially limited, and can be round holes, square holes and the like, and the shape of the film which needs to be expanded finally is required), and the position of the hole is set according to the actually required direction position of the film expansion, and the hole is covered by the film material.

According to the liquid electrode, further, the membrane material is similar to a balloon structure and can be expanded into a preset shape after conductive liquid is input; the distribution position, size and shape of the membrane material can be adjusted to control the distribution of the liquid within the predetermined target, and thus the area and direction of ablation.

According to the liquid electrode of the present invention, the conductive solution may be a variety of conductive solutions, and may be composed of a liquid having good conductivity and excellent biocompatibility, such as a sodium chloride solution or a calcium chloride solution; the concentration of the conductive solution can vary and can be adjusted from pure water to a saturated solution (when a 1mm metal needle is used, and the length of the exposed metal needle is 10mm, about 200 μ L of liquid is required to wrap the metal needle into an ablation electrode with a diameter of 2mm by using the conductive liquid). In addition, reference may also be made to the use of liquid metals which are more conductive.

When the liquid electrode is used, at least one electrode is electrified and at least one electrode is grounded, and when the liquid electrode is electrified, the liquid electrode can bear pulse voltage of 3000-4000V, the pulse width is 0.01-100 mu s, and the pulse voltage is 1 kHZ-1 MHZ.

According to the liquid electrode of the present invention, further, a self-made pulse generator may be used, and other existing pulse generators may also be used.

According to the liquid electrode, the electrode metal electrode needle can be replaced by a medical flexible catheter, and can be applied to minimally invasive ablation of human body lumen tissues.

The invention provides a pulse ablation method capable of increasing ablation area and controlling ablation direction, which can increase the ablation area of an original electrode or reduce the size of the electrode, and specifically comprises the following steps:

the liquid electrode is preferably applied, and a certain amount of conductive solution is injected outside the preset position of the liquid electrode to increase the area of the ablation electrode; under the premise of not changing the size of the original electrode, the effective ablation size of the electrode is increased by injecting the conductive solution to enlarge the ablation area, and the size which can be increased by the electrode depends on the volume amount which can be injected by the conductive solution; or under the condition of smaller electrode size, the effective ablation size of the electrode is increased to the size commonly used in clinic by injecting the conductive solution, the size of the electrode can be increased by 2-10 times, the ablation effect equivalent to that of the traditional electrode is met, and the puncture wound is reduced; by controlling the distribution of the liquid within the intended target, the direction of ablation can also be controlled.

One aspect of the application relates to a pulse ablation method and a liquid electrode, which can increase the ablation area and control the ablation direction. The method enlarges the ablation area by injecting a certain amount of conductive solution outside the preset position of the traditional pulse ablation electrode to increase the size of the ablation electrode. The ablation area can be enlarged on the premise of not changing the size of the original electrode, or the ablation effect which is the same as that of the conventional electrode can be realized under the condition of smaller size. Additionally, by controlling the distribution of the liquid within the intended target, the direction of ablation can also be controlled. Another aspect of the present application relates to a liquid electrode. The electrode comprises a positive electrode and a negative electrode, and the conductive liquid with certain concentration is injected into the preset area around the thin metal needle, so that puncture wound is reduced, the ablation area is increased, the size and the direction of the opening of the preset area can be changed to effectively select the preset area, and the controllability of the ablation direction is realized.

In some embodiments of the present application, the conductive liquid may be comprised of a 0-26.5% (30 ℃) sodium chloride solution. After the metal needle is inserted into the preset tissue, the conductive solution is delivered to the preset tissue through the injector, and a certain space is expanded outside the metal needle to increase the ablation area and control the ablation direction. And sucking out the conductive liquid after the electroporation is finished.

In some embodiments of the present application, the front end of the metal needle is wrapped with a membrane material having a hole with a controllable direction, the membrane material expands to a certain shape under a certain pressure of conductive liquid, and the conductive liquid forms a conductive layer on the outer surface of the membrane material through the hole of the membrane material to increase the controllable ablation area.

In some embodiments of the present application, the open pore area of the electrode membrane material is controllable for controlling the direction of distribution of the conductive liquid within the tissue, and thus the extent of distribution of the electric field.

Description of the drawings:

FIG. 1 is a schematic diagram of a liquid electrode according to an embodiment of the present application;

FIG. 2 is a front end comparison view of a metal electrode needle before and after liquid electrode injection;

FIG. 3 is a schematic diagram of controlling the distribution of liquid electrode conductive solution and thus the direction of ablation;

FIG. 4 is a schematic comparison of potato ablation areas under different diameter metallic copper electrodes;

FIG. 5 is a schematic illustration of potato ablation results with the addition of conductive liquid to expand the ablation size;

FIG. 6 is a schematic representation of potato ablation using different concentrations of different types of conductive solutions.

The specific implementation mode is as follows:

various exemplary embodiments of the present application are described in detail below with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps set forth in these embodiments, numerical values do not limit the scope of the present application unless specifically stated otherwise.

The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the application, its application, or uses.

FIG. 1 is a schematic view of a liquid electrode according to an embodiment of the present application

As shown in fig. 1, the liquid electrode 11 of the present application is composed of a metal electrode needle 12, a membrane material 13, and a syringe 14 used in pairs.

The metal electrode needle 12 is divided into a front end 15, a middle section 16 and a tail end 17. The front end 15 is an exposed end, namely a pulse voltage output end, the metal on the surface of the electrode needle of the front end 15 is exposed and is provided with small holes, and a film material 13 which can be expanded and has a hole structure is arranged in the hole opening direction. After the conductive liquid is injected into the metal needle, the membrane material 13 is propped open, and the conductive liquid can penetrate through the small holes to form a conductive layer on the outer surface of the membrane material 13. The middle section 16 metal electrode needle is wrapped up by insulating material outward, does not participate in the ablation process, can increase the puncture depth, is convenient for the handheld puncture of operator. The tail end 17 is divided into an injector connecting end 18 and a pulse generator connecting end 19, wherein the injector connecting end 18 is the place where the metal electrode needle 12 is connected with the injector 14 and can be matched by adopting a thread structure; the pulse generator connecting end 19 is a pulse voltage input end, the metal electrode needle 12 can be partially exposed, and the pulse generator is connected with the metal electrode needle 12 through an alligator clip.

The conductive liquid is composed of a liquid having good conductivity and excellent biocompatibility. After the metal needle is inserted into the predetermined tissue, the conductive solution is delivered to the predetermined tissue through the hollow structure of the metal needle, so that the membrane material 13 is expanded, and a certain space is expanded outside the metal needle to increase the ablation area and control the ablation direction.

The syringe 14 is matched with the metal electrode needle 12 through a thread structure, certain sealing performance is guaranteed, and the conductive liquid is pushed into the metal electrode needle 12 through the syringe 14. A scale system is arranged on the surface of the injector 14 so as to accurately determine the volume of the delivered conducting solution; the syringe 14 can be fixed by a certain fixing means to ensure that the electrode does not shift during the puncture ablation.

Specifically, in the liquid electrode 11 of the present application, a certain amount of conductive liquid is first sucked through the syringe 14, then the syringe 14 is connected to the metal electrode needle 12 in a matching manner, and then the metal electrode needle 12 is connected to a pulse generator (not shown) through the pulse generator connection end 19. The insertion depth of the electrode needle 12 is selected according to the treatment requirement, after the electrode needle 12 is inserted and fixed, a certain amount of conductive liquid is injected to the front end 15 of the electrode needle to expand the membrane material 13, and finally, the pulse generator is turned on to apply pulse voltage to the preset tissue. After the pulse therapy is finished, the conductive liquid is drawn back and the liquid electrode 11 is taken out.

FIG. 2 is a front end comparison view of a metal electrode needle before and after liquid electrode injection

Fig. 2(a) is an enlarged schematic view of the tip of the metal electrode needle when no liquid is injected. The surface of the front end 21 of the metal electrode needle is provided with a film material 22 which can be expanded and has an open pore structure, and when no liquid is injected, the film material 22 is tightly attached to the surface of the metal electrode needle.

Fig. 2(B) is an enlarged schematic view of the front end of the metal electrode needle after the liquid is injected. The membrane structure 22 at the front end 21 of the metal electrode needle is expanded, and can be expanded into a preset shape after the conductive liquid is injected, so that the size of the metal electrode needle is increased. In addition, the direction of ablation may also be changed by changing the expanded shape. The direction of the openings and the size of the holes in the film material 22 can be adjusted to control the distribution of the liquid within the intended target and thus the direction of ablation.

FIG. 3 is a schematic diagram of controlling the distribution of liquid electrode conductive solution and thus the direction of ablation

The distribution of liquid in a preset target is controlled by changing the distribution and the size of the opening at the front end of the metal electrode needle and the opening direction and the size of the opening on the membrane material, so that the ablation direction is controlled.

Fig. 3(a) is an embodiment of controlling the distribution of the conductive liquid. At this time, the opening range of the front end 31 of the metal electrode needle is a quarter region (90 degrees), and correspondingly, the amplification range of the membrane material 32 is a 90-degree sector region in the same direction. The direction of ablation can be varied by varying the extent of the aperture region and its angle relative to the axis.

Fig. 3(B) is another embodiment of controlling the distribution of the conductive solution. At the moment, the aperture of the opening of the front end 31 of the metal electrode needle is gradually reduced from the needle point to the middle section along the electrode needle, the membrane material 32 is expanded into a water drop shape after the conductive liquid is injected, and the direction and the area of ablation are realized by changing the shape of the membrane material of the front end 31 of the metal electrode needle.

Potato tuber ablation embodiments of the present invention.

The ablation electrode test is carried out by using 5-3-2.2 cm square potato tuber tissues, the increasing effect of the liquid electrode on the pulse ablation range, the safety and the stability of the liquid electrode are verified, and the liquid electrode can be further verified by carrying out in-vivo experiments on mice subsequently. The experiment firstly researches the ablation conditions of different copper electrodes with different thicknesses, and finds that the ablation effect is related to the diameter of the output end of the electrode; then, the traditional electrode is combined with the conductive liquid, and the electrode under the liquid amplification can generate a good ablation effect; finally, the relationship between the conductivity of the liquid and the ablation effect is explored, and the liquid can generate the ablation effect and is related to the concentration of the liquid.

Example 1: comparison of potato ablation area under different diameter metallic copper electrodes, as shown in fig. 4.

Two-pin copper electrodes of different diameters (electrode length 8cm, exposed end 1.5cm) were used for the experiments. The diameter of the very fine electrode 41 was 0.1mm, the diameter of the fine electrode 42 was 0.3mm, and the diameter of the thick electrode 43 was 1 mm. In the experiment implementation process, the anode and the cathode of the electrode are respectively and vertically inserted into the potatoes at the interval of 1 cm. The tail end of the electrode is externally connected with a pulse generator, and the used pulse parameters are pulse voltage 800V, pulse width 100 mus, pulse number 60 and pulse frequency 1 Hz.

In fig. 4, A, B, C show the status of potato ablation under the extra fine electrode 41, the fine electrode 42 and the coarse electrode 43, and 44, 45 and 46 show a plan view (left), a tangential sectional view (middle) and a side sectional view (right). The potato ablation zone length 47 and width 48 in the top view 44 are measured using a graduated scale. Measuring the average ablation length under the superfine electrode 41 to be 1.3cm and the average ablation width to be 1.1 cm; the average ablation length under the thin electrode 42 is 1.6cm, and the average ablation width is 1.5 cm; the average ablation length under the thick electrode 43 is 1.9cm, and the average ablation width is 1.9 cm; the length 44 of the potato ablation zone in the tangential cross-sectional view 45 is measured using a graduated scale. Measuring the average ablation length under the superfine electrode 41 to be 1.4 cm; the average ablation length under the thin electrode 42 is 1.7 cm; the average ablation length under the thick electrode 43 is 1.9 cm; the width 45 of the potato ablation zone in the side cut profile 46 is measured using a graduated scale. Measuring the average ablation width under the superfine electrode 41 to be 1.3 cm; the average ablation width under the thin electrode 42 is 1.6 cm; the average ablation width under the thick electrode 43 is 2.0 cm.

Comparing the data, the ablation area size is positively correlated with the electrode diameter size. The larger the electrode size is, the larger the ablation area is, and the better the ablation effect is.

Example 2: the potato ablation results were augmented by the addition of conductive liquid to expand the ablation size, as shown in fig. 5.

Perforating the potato at predetermined position and injecting liquid (10% CaCl)₂Solution), a copper electrode having a radius of 0.1mm, a length of 8cm and an exposed end of 1.5cm was placed at the center of the hole. The volume size of the conductive liquid is changed by changing the diameter size of the circular hole. In the experiment, the radiuses of two groups of round holes are set to be 1mm and 2mm, the depth is 1.5cm, the distance between circle centers is 1cm, and the same copper electrodes are arranged in the middle of the round holes. In addition, a set of copper electrodes without liquid was set up as a control. The tail end of the electrode is externally connected with a pulse generator, and the used pulse parameters are pulse voltage 800V and pulse width100 mus, number of pulses 60, pulse frequency 1 Hz.

A, B, C in FIG. 5 are graphs of the ablation status of potatoes with different volumes of conductive liquid (51: metal electrode with 0.1mm diameter without conductive liquid; 52: liquid amplification electrode with 1mm diameter; 53: liquid amplification electrode with 2mm diameter). Wherein 54, 55, 56 are respectively a top view (left), a tangential sectional view (middle), and a side cut sectional view (right). The lengths 57 and the widths 58 of the potato ablation areas in the plan view 54 are measured by using a graduated scale (parallel to 3 sets of experiments), and the average ablation length under the size of the metal electrode 51 is measured to be 1.4cm, and the average ablation width is measured to be 1.3 cm; the average ablation length of the 1mm liquid amplification electrode 52 is 1.7cm, and the average width is 1.8 cm; the average ablation length of the 2mm liquid amplification electrode 53 is 1.9cm, and the average width is 1.9 cm; the average ablation length of the potato in the tangent section diagram 55 is 1.4cm by measuring the length 57 of the potato ablation area by using a graduated scale; the average ablation length was 1.6cm for a 1mm liquid amplification electrode 52 size; the average ablation area length under the size of the 2mm liquid amplification electrode 53 is 1.8 cm; measuring the width 58 of the potato ablation area in the side-cut section 53 by using a graduated scale, wherein the average ablation length under the original electrode size 51 is 1.6 cm; the average width of the ablation area under the size of the 1mm liquid amplification electrode 52 is 1.9 cm; the average ablation width at the 2mm liquid amplification electrode 53 size was 2.0 cm.

Comparing the above data, it can be known that the radius of the electrode is enlarged by adding the conductive liquid under the original electrode size, and the ablation under the enlarged electrode size has better ablation range and effect compared with the original electrode size.

Example 3: the potato ablation profile with different concentrations of different types of conductive solutions is shown in fig. 6.

A hole (round hole 61 with diameter of 2mm and depth of 1.5cm) is punched at a predetermined position of potato, and different concentrations and kinds of liquid are injected, and a copper electrode with radius of 0.1mm, length of 8cm and exposed end of 1mm is placed at the center of the hole. The tail end of the electrode is externally connected with a pulse generator, and the used pulse parameters are pulse voltage 800V, pulse width 100 mus, pulse number 60 and pulse frequency 1 Hz.

FIG. 6(A) is a tangential section 621 and a side cut section 631 of potato ablation conditions with NaCl solutions of different concentrations (parallel 3 sets of experiments). Wherein, a, b, c, d, e correspond to no liquid 64, ultrapure water 65, 1% NaCl solution 66, 5% NaCl solution 67, 10% NaCl solution 68, respectively. As can be seen from fig. 6(a) a and b, the size of the ablation area under ultrapure water is not much different from the size of the ablation area under copper wire without liquid; as can be seen from FIGS. 6(A) b-e, the potato ablation area was significantly increased compared to pure water when NaCl solution was used; along with the increase of NaCl concentration, the ablation area is gradually increased, and the ablation area and the ion concentration are in positive correlation.

FIG. 6(B) shows the use of different CaCl concentrations₂Potato ablation conditions under solution are tangent section 622 and side cut section 632. Wherein, a, b, c, d and e correspond to no liquid 64, ultrapure water 65 and 1% CaCl respectively₂Solution 69, 5% CaCl₂Solution 610, 10% CaCl₂And (3) a solution 611. As can be seen from fig. 6(B) a and B, the size of the ablation area under ultrapure water is not much different from the size of the ablation area under copper wire without liquid; as shown in FIGS. 6(B) B-e, CaCl was used₂When the solution is used, the potato ablation area is obviously increased compared with pure water; with CaCl₂The concentration is increased, and the ablation area is gradually increased. This is consistent with the results when using NaCl solution, again demonstrating a positive correlation between the size of the range ablated and the ion concentration.

As can be seen from the above, the liquid having high ion concentration and excellent conductivity is advantageous for increasing the ablation area, and therefore, it should be noted that the liquid having better conductivity can be referred to as a liquid metal having better conductivity.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and decorations can be made without departing from the concept of the present invention, and these modifications and decorations should also be regarded as being within the protection scope of the present invention.