Microwave ablation needle and ablation assembly

Abstract

A microwave ablation needle (100) and an ablation assembly. The microwave ablation needle comprises an outer tube (1), an inner tube (2), and a coaxial cable (3) which are coaxially sleeved in sequence, as well as a connection component (4) used for coaxially fixing and connecting the coaxial cable (3) to the outer tube (1), wherein the connection component (4) is connected to the inner wall of the outer tube (1) and the outer wall of the coaxial cable (3) in a sealed mode, so as to form a circulating cooling passage passing through a gap between the outer tube (1) and the inner tube (2), and a gap between the inner tube (2) and the coaxial cable (3); in a plane perpendicular to the length extension direction of the ablation needle, the outer tube (1) and the inner tube (2) define a first flow cross section, the inner tube (2) and the coaxial cable (3) define a second flow cross section, and a difference value between the area of the first flow cross section and the area of the second flow cross section is within a preset threshold range; in a microwave ablation process, a cooling medium carries out cooling by means of the circulating cooling passage, so that the pressure balance of the cooling medium through the first flow cross section and the second flow cross section is achieved. Therefore, the present invention can solve the problem in the prior art of unbalanced pressure of cooling water.

Description

Microwave ablation needle and ablation component Technical Field

[0001] The present invention relates to the technical field of microwave ablation, and in particular to a microwave ablation needle and an ablation component. Background Art

[0002] Microwave ablation (MVA) originated in Japan. In 1944, Japanese researcher Seki successfully used MVA to treat primary liver cancer. In 1996, Chinese researcher Dong Baowei further improved MVA. Currently, MVA technology has been widely used in clinical cancer treatment due to its advantages, including high thermal efficiency, rapid heating rate, relatively uniform high-temperature field, complete necrosis in the coagulation zone, and minimal impact on blood flow. Microwave ablation primarily relies on the microwave thermal effect, which triggers a large number of ions in the intracellular and extracellular fluids to vibrate violently. The collision and friction between the ions generate a large amount of heat, causing the temperature to rise and causing coagulation and necrosis of tumor tissue. The first generation of microwave antennas suitable for clinical tumor ablation was introduced in 1996. However, these antennas still have many limitations, such as the radiator being located at the tip, which is prone to damage during puncture; the lack of a built-in antenna cooling device, which leads to excessively high antenna temperatures and skin burns; increased central carbonization and degraded coagulation shape, which can easily cause tailing; and the need for a puncture guide, which is inconvenient to operate. In 2003, the second-generation microwave antenna achieved a truly integrated system for puncture, radiation, and water-cooling circulation. The needle tip is made of a hard material, eliminating the need for a guide needle and enabling direct puncture. It can withstand higher power output, extending the ablation range compared to previous technologies. While the ablation zone remains elliptical, the latest microwave antennas can now produce circular ablation zones. my country has reached international leadership in MVA treatment of both benign and malignant solid tumors, and the delivery method has expanded from solely image-guided surgery to a combination of multiple approaches, including open surgery and laparoscopic procedures.

[0003] In the prior art, patent publication number CN108030549A discloses a unilateral microwave device comprising an ablation needle tube and an ablation needle. The ablation needle tube is provided with a microwave coaxial cable, the ablation needle is provided with an antenna, the microwave coaxial cable is connected to the antenna, the outer ring of the microwave coaxial cable is provided with a metal adapter cover, and the outer ring of the antenna is provided with an adjustment member for adjusting the direction of the microwave. The microwave coaxial cable comprises an inner core, a dielectric layer, and an outer cable layer. The inner core and dielectric layer of the microwave coaxial cable near the ablation needle pass through the metal adapter cover, the inner core is connected to the antenna, and an arc-shaped metal sheet is fixedly connected to the metal adapter cover. A water inlet hose is also provided under the handle, connected to a capillary tube, and the capillary tube extends to the front end of the ablation needle tube. The front end of the capillary tube is provided with a water outlet. Cooling water flows out of the outlet and flows back into the handle within the ablation needle tube, and the cooling water flows out through the water outlet hose.

[0004] Patent publication number CN109953824A discloses a microwave ablation needle comprising an insulating needle tip, a metal needle shaft, and an electrical isolator. The insulating needle tip is provided with a first accommodating cavity, and the metal needle shaft is provided with a second accommodating cavity, which allows the metal needle shaft to float. Because the metal needle shaft is in a floating state, it acts as a choke during microwave ablation and does not radiate, inhibiting the propagation of microwave signals in the direction of the microwave input. During the ablation process, the microwave signal radiates energy outward only through the insulating needle tip, thereby eliminating the tailing phenomenon seen in traditional designs, ensuring a stable ablation morphology, and making it more spherical.

[0005] Patent publication number CN101711705A discloses a microwave ablation needle and a microwave ablation therapeutic device. The patent relates to a microwave ablation needle structure and a microwave ablation therapeutic device using the same. The microwave ablation needle primarily comprises an ablation needle, an ablation needle tube, a microwave coaxial cable, a capillary tube, a handle with a crank, and a temperature sensor. It also includes a mounting bracket containing a high-frequency connector, a water inlet connector, a water outlet connector, and an external connector for connecting the temperature sensor terminal, as well as a high-frequency connector with a locking spring and a water chamber within the handle for cold water circulation. Circulating water enters the capillary tube through the water inlet connector, then enters the water chamber through the ablation needle tube, and finally flows out through the water outlet connector. Microwave energy enters the microwave coaxial cable through the high-frequency connector and is radiated through the ablation needle. The microwave ablation therapeutic device comprises the microwave ablation needle, a microwave power source, and a computer control unit. It is primarily used for microwave ablation treatment of tumors.

[0006] Patent publication number CN206687768U discloses a high-efficiency condenser comprising a needle rod with an arc-shaped partition defining an inlet and outlet chambers. The inlet and outlet chambers are connected at their distal ends. The proximal end of the outlet chamber connects to a water tank, while the proximal end of the inlet chamber connects to a cold circulation capillary tube and a first water inlet and outlet pipe, which in turn connects to the water tank. A hole is defined at the proximal end of the needle rod, and a battery cell is crimped into the hole at the distal end of the microwave transmission cable. A handle is also provided at the proximal end of the needle rod, located outside the water tank.

[0007] However, the above existing technologies still have defects. The existing technologies are provided with a water inlet hose, which is connected to a capillary tube, which extends to the front end of the ablation needle tube. A water outlet is provided at the front end of the capillary tube. The cooling water flows out from the water outlet and flows back into the handle in the ablation needle tube. The cooling water flows out through the water outlet hose. This method easily causes water pressure imbalance, and requires higher capacity (input pressure) of the external cooling water input device, and higher pressure-bearing capacity of the overall (internal and external) structure. In addition, the entire space in the handle is small and the number of parts is large.

[0008] Summary of the Invention

[0009] The object of the present invention is to provide a microwave ablation needle and an ablation assembly to solve the problem of water pressure imbalance during ablation cooling in the prior art.

[0010] The first technical solution of the present invention is: a microwave ablation needle, comprising: an outer tube, an inner tube, a coaxial cable, and a connector for coaxially fixing the coaxial cable to the outer tube, the connector is sealed to the inner wall of the outer tube and the outer wall of the coaxial cable to form a circulating cooling passage through the gap between the outer tube and the inner tube, and the gap between the inner tube and the coaxial cable; in a plane perpendicular to the length extension direction of the ablation needle, the outer tube and the inner tube form a first flow section, and the inner tube and the coaxial cable form a second flow section, and the difference between the area of ​​the first flow section and the area of ​​the second flow section is within a preset threshold range; during the microwave ablation process, the cooling medium is cooled and cooled through the circulating cooling passage to achieve pressure balance of the cooling medium through the first flow section and the second flow section.

[0011] Preferably, the ablation needle also includes a puncture ablation part, which includes a needle head fixedly connected to the coaxial cable axially, the distal end of the needle head has a sharp spike, and the proximal end of the needle head is fixedly connected to the distal end of the inner conductor of the coaxial cable. The coaxial cable includes an inner conductor, an outer conductor and a dielectric. A radiation window is formed between the distal end of the outer conductor of the coaxial cable and the proximal end of the needle head. The distal end of the dielectric abuts the proximal end surface of the needle head. When the ablation process is started, the needle head serves as the antenna of the inner conductor, wherein the distal end of the inner conductor of the coaxial cable protrudes from the distal end of the coaxial cable dielectric, and the distal end of the coaxial cable dielectric protrudes from the distal end of the outer conductor of the coaxial cable.

[0012] Preferably, the puncture and ablation part also includes a conductive component covering the radiation window, and the conductive component is a tubular structure, which is sleeved to cover the radiation window. The needle includes a needle body and an annular connector arranged on the proximal surface of the needle body, the inner ring surface of the annular connector is fixedly connected to the inner conductor, the outer ring surface of the annular connector is connected to the inner wall of the conductive component, the proximal surface of the annular connector is the proximal surface of the needle, and the two ends of the conductive component are respectively abutted against the distal surface of the outer tube and the proximal surface of the needle body.

[0013] Preferably, the needle is made of metal, and the inner conductor and the annular connector are connected by a crimping process.

[0014] Preferably, the conductive component is made of high thermal conductivity ceramic material, and there is a micro gap between the two ends of the conductive component and the distal end surface of the outer tube and the proximal end surface of the needle body. The outer surfaces of the outer tube and the conductive component have a polytetrafluoroethylene insulation layer.

[0015] Preferably, the distance L between the radiation window and the proximal end of the ablation needle is (2n+1)*λ / 4, wherein n represents a positive integer and λ represents the wavelength of the electromagnetic wave when it is transmitted in the coaxial cable.

[0016] Preferably, the microwave ablation needle further includes a thermocouple, which extends along the length direction of the microwave ablation needle and is disposed in a cavity formed by the inner tube and the coaxial cable, or in a cavity formed by the outer tube and the inner tube.

[0017] Preferably, the distal end surface of the inner tube abuts the proximal end surface of the connector, and a plurality of connecting holes are provided on the side wall of the distal end of the inner tube. During the ablation and cooling process, the cooling medium forms a circulating cooling passage through the first flow section, the connecting holes and the second flow section.

[0018] Preferably, the outer tube is made of metal, the connecting piece is a magnetic ring or a copper ring, and the distal end surface of the inner tube is welded to the connecting piece.

[0019] Preferably, the connecting piece is made of non-metallic material, a balun is provided on the connecting piece, and the distal end surface of the inner tube is fixedly connected to the connecting piece.

[0020] Preferably, the microwave ablation needle also includes a first water tank, a second water tank and a coaxial connector arranged along the length extension direction of the outer tube. The microwave ablation needle passes through the first water tank and the second water tank. The proximal end surface of the outer tube of the ablation needle is welded to the first inlet of the first water tank. The inner tube of the ablation needle passes through and is welded to the first outlet of the first water tank. The proximal end surface of the inner tube is welded to the second inlet of the second water tank. The proximal end of the coaxial cable passes through and is sealed with the second outlet of the second water tank. The first water tank and the second water tank are respectively provided with a connecting port for circulating cooling medium. The coaxial cable is electrically connected to the corresponding terminal in the coaxial connector.

[0021] Preferably, the microwave ablation needle also includes a first water tank, a second water tank and a coaxial connector arranged along the length extension direction of the outer tube, the microwave ablation needle passes through the first water tank and the second water tank, the distal end of the second water tank is adapted to the proximal end of the first water tank and forms a blockage, the proximal end of the outer tube of the ablation needle extends to the inner cavity of the first water tank, the outer wall of the outer tube is sealed with the first water tank, the proximal end of the inner tube of the ablation needle extends to the inner cavity of the second water tank, the outer wall of the inner tube is sealed with the second water tank, the first water tank and the second water tank are respectively provided with a connecting port for circulating cooling medium, the distal end of the coaxial connector is adapted to the proximal end of the second water tank and forms a blockage, and the coaxial cable is electrically connected to the corresponding terminal in the coaxial connector.

[0022] Based on the same concept, the second technical solution of the present invention is: an ablation assembly, comprising any one of the microwave ablation needles described above.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] 1. In the technical solution of the present invention, by providing an inner tube, the cooling channel forms a circulating cooling loop, and the cross-sectional area enclosed by the outer tube and the inner tube is close to the cross-sectional area enclosed by the inner tube and the coaxial cable, so that the cross-sectional areas of the water inlet and return channels are close, so that the water pressures of the water inlet and return water can be balanced, thereby solving the problem in the prior art of higher requirements for the capacity of the external input device for cooling water and higher pressure-bearing capacity of the overall structure.

[0025] 2. In the technical solution of the present invention, the inner tube and the outer tube are arranged into an eccentric structure, thereby providing a better accommodation space, so that the thermocouple can be better accommodated in the channel between the outer tube and the inner tube or the channel between the inner tube and the coaxial cable, which is conducive to reducing the radial size of the microwave ablation needle, thereby benefiting the improvement of surgical accuracy.

[0026] 3. The technical solution of the present invention provides a conductive component with a tubular structure. On the one hand, the conductive component is sleeved to cover the radiation window, and the inner conductor and the needle are connected through the annular connector, thereby forming a three-layer circular tube nested connection structure, which is more stable and the needle is not easy to fall off. On the other hand, the conductive component is sleeved on the surface of the annular connector and the outer conductor of the needle, and the distal end face and the proximal end face of the conductive component are in contact with the proximal end face of the needle body and the distal end face of the outer tube. No adhesive is used for fixed connection, and there is a micro gap. Therefore, a certain expansion and contraction space is provided when the temperature changes, thereby reducing the risk of stress rupture of the conductive component at high temperature.

[0027] 4. The conducting component of the technical solution of the present invention can be made of high thermal conductivity ceramics, that is, alumina material. On the one hand, the conducting component is sleeved and covered on the radiation window, and the energy loss of microwaves passing through the high thermal conductivity ceramic material is small. On the other hand, the high thermal conductivity ceramic has good thermal conductivity and can play a good role in conducting the heat of the needle.

[0028] 5. The needle tip of the present invention is made of metal, which not only has excellent puncture performance but also good machinability. The connection to the inner conductor is not made by adhesive but by crimping, making the connection between the needle tip and the inner conductor more stable and reliable, and less likely to fall off. In addition, the metal needle tip is easier to process than the ceramic needle tip used in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG1 is a schematic diagram of the overall structure of a microwave ablation needle according to an embodiment;

[0030] FIG2 is a schematic structural diagram of the distal end of a microwave ablation needle according to an embodiment;

[0031] FIG3 is a schematic diagram of the cross-sectional structure of an ablation needle tube according to an embodiment;

[0032] FIG4 is a schematic structural diagram of the proximal end of a microwave ablation needle according to an embodiment;

[0033] FIG5 is an enlarged structural diagram of point A in FIG4 ;

[0034] FIG6 is an enlarged structural diagram of point B in FIG4 ;

[0035] FIG7 is a schematic structural diagram of the proximal end of a microwave ablation needle according to an embodiment;

[0036] FIG8 is an enlarged structural diagram of point A in FIG7 ;

[0037] FIG9 is an enlarged structural diagram of point B in FIG7 ;

[0038] FIG10 is a schematic diagram of the ablation effect of a microwave ablation needle in the prior art;

[0039] FIG11 is a schematic diagram of the ablation effect of the microwave ablation needle of the present application.

[0040] Description of reference numerals:

[0041] 100-microwave ablation needle; 1-outer tube; 2-inner tube; 201-connecting hole; 3-coaxial cable; 301-outer conductor; 302-dielectric; 303-inner conductor; 4-connector; 5-needle; 501-needle body; 502-annular connector; 6-radiation window; 7-conduction component; 8-thermocouple; 9-first water tank; 901-first inlet; 902-first outlet; 10-second water tank; 1001-second inlet; 1002-second outlet; 11-coaxial connector. DETAILED DESCRIPTION

[0042] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and functions of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, they should not be understood as limiting the present invention. In addition, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, features specified as "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0043] It should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0044] In addition, in the description of this application, the "proximal end" and "distal end" are commonly used terms in the medical field. Specifically, the "proximal end" refers to the end closest to the operator, the "proximal surface" refers to the end surface closest to the operator, the "distal end" refers to the end farther from the operator, and the "distal surface" refers to the end surface farther from the operator.

[0045] First embodiment

[0046] This embodiment provides a microwave ablation needle 100, refer to Figures 1 to 3, Figure 1 is a schematic diagram of the overall structure of the microwave ablation needle 100 of this embodiment, Figure 2 is a schematic diagram of the structure of the distal end of the ablation needle, and Figure 3 is a schematic diagram of the cross-sectional structure of the ablation needle tube, including: an outer tube 1, an inner tube 2, a coaxial cable, and a connector 4 for coaxially fixedly connecting the coaxial cable to the outer tube 1, which are coaxially sleeved in sequence. The connector 4 is sealed to the inner wall of the outer tube 1 and the outer wall of the coaxial cable to form a circulating cooling passage through the gap between the outer tube 1 and the inner tube 2, and the gap between the inner tube 2 and the coaxial cable; in a plane perpendicular to the length extension direction of the ablation needle, the outer tube 1 and the inner tube 2 form a first flow section, and the inner tube 2 and the coaxial cable form a second flow section, and the difference between the area of ​​the first flow section and the area of ​​the second flow section is within a preset threshold range; during the microwave ablation process, the cooling medium is cooled and cooled through the circulating cooling passage to achieve pressure balance of the cooling medium through the first flow section and the second flow section.

[0047] In this embodiment, by providing an inner tube 2, the cooling channel forms a circulating cooling loop, and the cross-sectional area enclosed by the outer tube 1 and the inner tube 2 is close to the cross-sectional area enclosed by the inner tube 2 and the coaxial cable, so that the cross-sectional areas of the water inlet and return channels are close, so that the water pressures of the inlet and return water can be balanced, thereby solving the problem in the prior art of higher requirements on the capacity of the external input device for cooling water and higher requirements on the pressure-bearing capacity of the overall structure.

[0048] Preferably, referring to Figure 2, the ablation needle also includes a puncture and ablation portion, which includes a needle 5 axially fixedly connected to the coaxial cable, the distal end of the needle 5 has a spike, and the proximal end of the needle 5 is fixedly connected to the distal end of the inner conductor 303 of the coaxial cable. The coaxial cable 3 includes an inner conductor 303, an outer conductor 301 and a dielectric 302. A radiation window 6 is formed between the distal end of the outer conductor 301 of the coaxial cable and the proximal end of the needle 5, and the distal end of the dielectric 302 abuts against the proximal end surface of the needle 5. During the ablation process, the needle 5 is the antenna of the inner conductor 303, wherein the distal end of the inner conductor 303 of the coaxial cable 3 protrudes from the distal end of the coaxial cable dielectric 302, and the distal end of the coaxial cable dielectric 302 protrudes from the distal end of the coaxial cable outer conductor 301. The radiation window 6 radiates microwaves to perform microwave heating on the target tissue to achieve tissue ablation.

[0049] In the technical solution of this embodiment, the ablation needle has an ablation puncture portion, the needle tip 5 of which is fixedly connected to the inner conductor 303 of the coaxial cable, preferably using a crimping method to avoid the risk of needle tip 5 falling off during the ablation puncture process. The distal end of the dielectric 302 abuts the proximal surface of the needle tip 5. The radiation window 6 formed between the distal end of the outer conductor 301 and the proximal end of the needle tip 5 radiates microwaves, reducing microwave energy loss and accurately performing microwave ablation on the target tissue.

[0050] Preferably, referring to Figure 2, the puncture and ablation part also includes a conductive component 7 covering the radiation window 6. The conductive component 7 is a tubular structure, which is sleeved to cover the radiation window 6. The needle 5 includes a needle body 501 and an annular connector 502 arranged on the proximal surface of the needle body 501. The inner ring surface of the annular connector 502 is fixedly connected to the inner conductor 303, and the outer ring surface of the annular connector 502 is connected to the inner wall of the conductive component 7. The proximal surface of the annular connector 502 is the proximal surface of the needle 5, and the two ends of the conductive component 7 are respectively abutted against the distal surface of the outer tube 1 and the proximal surface of the needle body 501.

[0051] Referring to Figure 2, a tubular conductive component 7 is provided in the technical solution of this embodiment. On the one hand, the conductive component 7 is sleeved to cover the radiation window 6, and the inner conductor 303 is connected to the needle 5 through the annular connector 502, thereby forming a three-layer circular tube nested connection structure. The structure is more stable and the needle 5 is not easy to fall off. On the other hand, the conductive component 7 is sleeved on the surface of the annular connector 502 and the outer conductor 301 of the needle 5, and the distal end face and the proximal end face of the conductive component 7 are in contact with the proximal end face of the needle body 501 and the distal end face of the outer tube 1. No adhesive is used for fixed connection, and there is a micro gap. Therefore, a certain expansion and contraction space is provided when the temperature changes, thereby reducing the risk of stress rupture of the conductive component 7 at high temperature.

[0052] Preferably, the needle 5 is made of metal, and the inner conductor 303 and the annular connector 502 are connected by a crimping process.

[0053] The needle 5 is made of metal, which not only has good puncture performance, but also has good processability. The connection with the inner conductor 303 is not in the form of glue, but can be crimped, so that the connection between the needle 5 and the inner conductor 303 is more stable and reliable, and not easy to fall off. In addition, the metal needle 5 is easier to process and obtain than the ceramic needle 5 used in the prior art. The traditional ceramic needle 5 takes into account the puncture function and is connected to the needle tube at the rear end. The needle tube may be made of non-metal. In order to completely set the microwave antenna inside the ceramic needle 5 and immerse it in the cooling medium, the connection must not leak. Therefore, the ceramic needle 5 must be provided with a step, and there is a hidden danger of microcracks in the ceramic during sintering. If there are microcracks, there is a risk of the ceramic needle 5 breaking due to the high temperature during the ablation process. This embodiment uses a metal needle 5. During ablation, the metal needle 5 acts as a microwave antenna and will generate self-heating. Unlike the traditional method of placing the antenna in a cooling medium so that the cooling medium can carry away excess heat, the metal needle 5 cannot generate self-heating. However, because the essence of microwave ablation is that heat causes tissue coagulation, another name for ablation is thermal coagulation. Therefore, as long as the temperature of the needle 5 can be controlled within a certain range, this self-heating is still considered beneficial.

[0054] In one embodiment, the conductive component 7 abuts the proximal end surface of the needle body 501 and the outer tube 1. Both the needle body 501 and the outer tube 1 are made of stainless steel, which has a thermal conductivity of approximately 20 W / m·k. The conductive component 7 is made of a high-thermal-conductivity ceramic material, which is higher than other non-metallic materials, such as 99% alumina, which has a thermal conductivity of approximately 30 W / m·k. This material can promptly transfer excess heat from the needle 5 to the outer tube 1, thereby preventing excessive heating of the needle 5. Preferably, since the conductive component 7 abuts the needle body 501 and the outer tube 1, to improve heat conduction efficiency, a soft thermally conductive medium can be filled in the gaps around the conductive component 7. In one embodiment, tin can also be used when welding the connector to the inner tube. Tin can be filled into the gaps between the conductive component 7 and the coaxial cable 3, the outer tube 1, and the connector 4 (tin has a thermal conductivity of 67 W / m·k), thereby promptly transferring excess heat from the needle 5 to the outer tube, which is then further cooled by the cooling medium.

[0055] Preferably, the conducting component 7 is made of high thermal conductivity ceramic material, and there is a micro gap between the two ends of the conducting component 7 and the distal end surface of the outer tube 1 and the proximal end surface of the needle body 501. The outer surfaces of the outer tube 1 and the conducting component 7 have a polytetrafluoroethylene insulation layer.

[0056] The conductive component 7 can be made of a high-thermal-conductivity ceramic, namely, alumina. On the one hand, the conductive component 7 is positioned over the radiation window 6, minimizing microwave energy loss as it passes through the high-thermal-conductivity ceramic. Furthermore, the high-thermal-conductivity ceramic exhibits excellent thermal conductivity, effectively conducting heat away from the needle 5. Furthermore, alumina exhibits excellent high-temperature resistance and mechanical strength, ensuring that the needle does not deflect or bend. The size of the microgap depends on the lengths of the conductive component 7, the needle 5, the outer tube 1, and other components, as well as the combined deformation range of the various materials used for the conductive component 7, the needle 5, and the outer tube 1 within a predetermined temperature range.

[0057] Preferably, the distance L between the radiation window 6 and the proximal end of the ablation needle is (2n+1)*λ / 4, where n represents a positive integer and λ represents the wavelength of the electromagnetic wave when transmitted in the coaxial cable, so as to reduce the self-heating temperature of the needle 5.

[0058] For example, based on existing scientific research, we can easily know that: V=C·√(1 / (ε·μ))……(1) V=λ·f……(2);

[0059] Among them, V is the propagation speed of electromagnetic waves, ε is the relative dielectric constant of the propagation medium, μ is the magnetic permeability of the propagation medium, C is the speed of light in vacuum, λ is the wavelength of the electromagnetic wave, and f is the frequency of the electromagnetic wave.

[0060] Coaxial cable 3 is an unbalanced transmission line. Due to the interference and superposition of reflected waves, nodes are formed at phase differences of 2n / 4*2π and antinodes are formed at phase differences of (2n+1) / 4*2π. Radiation window 6 needs to avoid these nodes; positioning it at the antinodes reduces the temperature of needle tip 5 due to self-heating. This means that L ≈ (2n+1)·λ / 4, where n∈N (in the natural number domain).

[0061] If the dielectric 302 of the coaxial cable 3 is PTFE (Polytetrafluoroethylene), whose relative dielectric constant ε≈2 and magnetic permeability μ=1, is substituted into the above formula (1), the transmission speed V of the electromagnetic wave in the dielectric 302 is approximately equal to 0.7071C. When the microwave frequency f is 2450 MHz, the wavelength λ in the propagation medium can be calculated according to the above formula (2) as 86.58 mm and λ / 4 as 21.65 mm.

[0062] In combination with the length of the ablation needle required in actual medical use scenarios, the radiation window 6 can be optionally set to about 108 mm, which is convenient for doctors to operate and can reduce the self-heating of the needle 5.

[0063] Preferably, referring to FIG. 2 or FIG. 3 , the microwave ablation needle 100 further includes a thermocouple 8, which extends along the length of the microwave ablation needle 100 and is disposed within the cavity formed by the inner tube 2 and the coaxial cable, or within the cavity formed by the outer tube 1 and the inner tube 2. When the position of the thermocouple 8 is different, other corresponding structural components are also adaptively adjusted to achieve the original design function.

[0064] The thermocouple 8 is used to collect the temperature inside the ablation needle and feed the collected temperature back to the control system of the ablation needle. The control system controls the ablation work of the ablation needle based on the temperature information collected by the thermocouple 8. In addition, in order to allow the thermocouple 8 to obtain a good accommodation space, the inner tube 2 and the outer tube 1 are axially eccentrically arranged.

[0065] Preferably, referring to Figure 2, the distal end surface of the inner tube 2 abuts against the proximal end surface of the connector 4, and a plurality of connecting holes 201 are provided on the side wall of the distal end of the inner tube 2. During the ablation and cooling process, the cooling medium forms a circulating cooling passage through the first flow section, the connecting holes 201 and the second flow section.

[0066] In this embodiment, multiple communication holes 201 are formed in the sidewall of the distal end of the inner tube 2. These communication holes 201 allow the gaps between the outer tube 1 and the inner tube 2, and between the inner tube 2 and the coaxial cable, to communicate through the gaps, forming a circulating cooling path. This facilitates cooling during the ablation process. Preferably, the communication holes 201 are evenly distributed along the circumference to ensure balanced water pressure during the circulation of the cooling medium.

[0067] Preferably, the outer tube 1 is made of metal, and the connector 4 is a magnetic ring or a copper ring to achieve the purpose of changing the phase of the reflected wave and reducing heat. The distal end surface of the inner tube 2 is welded to the connector 4.

[0068] The magnetic ring or the copper ring acts as a balanced-unbalanced converter, changing the phase of the reflected wave and reducing heat generation. The coaxial cable is an unbalanced transmission line, and the magnetic ring or the copper ring can also solve the problem of ablation tail.

[0069] Preferably, the connecting member 4 is made of non-metallic material, a balun is provided on the connecting member 4 , and the distal end surface of the inner tube 2 is fixedly connected to the connecting member 4 .

[0070] When the connector 4 is made of non-metallic material, a balun is provided on the connector 4 to suppress the reflection of electromagnetic waves, thereby solving the problem of ablation tailing.

[0071] 10-11 are schematic diagrams of the ablation effect of a microwave ablation needle in the prior art, and FIG11 is a schematic diagram of the ablation effect of a microwave ablation needle in the present application. It can be seen that the ablation area obtained in the prior art is elongated, while the ablation area obtained in the present application is closer to a circle.

[0072] Preferably, referring to Figures 4 to 6, the microwave ablation needle also includes a first water tank 9, a second water tank 10 and a coaxial connector 11 arranged along the length extension direction of the outer tube 1, the microwave ablation needle 100 passes through the first water tank 9 and the second water tank 10, the proximal end surface of the ablation needle outer tube 1 is welded to the first inlet 901 of the first water tank 9, the ablation needle inner tube 2 passes through and is welded to the first outlet 902 of the first water tank 9, the proximal end surface of the inner tube 2 is welded to the second inlet 1001 of the second water tank 10, the proximal end of the coaxial cable 3 passes through and is sealed with the second outlet 1002 of the second water tank 10, the first water tank 9 and the second water tank 10 are respectively provided with a connecting port for circulating cooling medium, and the coaxial cable is electrically connected to the corresponding terminal in the coaxial connector 11.

[0073] In this embodiment, the first water tank 9 has a first inlet 901 and a first outlet 902, and the second water tank 10 has a second inlet 1001 and a second outlet 1002. The proximal end surface of the ablation needle outer tube 1 is welded to the first inlet 901 of the first water tank 9, so that the cavity enclosed by the ablation needle outer tube 1 and the inner tube 2 is in communication with the first water tank 9; the inner tube 2 passes through and is welded to the first outlet 902 of the first water tank 9, so that the first water tank 9 is sealed; the proximal end surface of the inner tube 2 is welded to the second inlet 1001 of the second water tank 10, so that the cavity enclosed by the ablation needle inner tube 2 and the coaxial cable 3 is in communication with the second water tank 10; the proximal end of the coaxial cable 3 is sealedly connected to the second outlet 1002 of the second water tank 10, so that the second water tank 10 is sealed. In this way, a circulating cooling path is formed: first water tank 9 - cavity surrounded by outer tube 1 and inner tube 2 - communicating hole 201 - cavity surrounded by inner tube 2 and coaxial cable 3 - second water tank 10. Alternatively, a circulating cooling path is formed: second water tank 10 - cavity surrounded by inner tube 2 and coaxial cable 3 - communicating hole 201 - cavity surrounded by outer tube 1 and inner tube 2 - first water tank 9. The first water tank 9 and the second water tank 10 can be made of metal, which is easy to weld to the inner tube 2 and outer tube 1, convenient to process, and highly reliable.

[0074] Preferably, the first water tank 9 and the second water tank 10 can be provided with a detachable cover to facilitate internal cleaning, prevent excessive bacterial growth, or facilitate maintenance. The first water tank 9 and the second water tank 10 can also be provided with a stopper at a predetermined position to limit the cover, facilitating disassembly or welding during processing.

[0075] Second embodiment

[0076] Referring to Figures 7 to 9, the microwave ablation needle also includes a first water tank 9, a second water tank 10 and a coaxial connector 11 arranged along the length extension direction of the outer tube 1. The microwave ablation needle 100 passes through the first water tank 9 and the second water tank 10. The distal end of the second water tank 10 is adapted to the proximal end of the first water tank 9 and forms a blockage. The proximal end of the ablation needle outer tube 1 extends to the inner cavity of the first water tank 9. The outer wall of the outer tube 1 is sealed with the first water tank 9. The proximal end of the ablation needle inner tube 2 extends to the inner cavity of the second water tank 10. The outer wall of the inner tube 2 is sealed with the second water tank 10. The first water tank 9 and the second water tank 10 are respectively provided with a connecting port for circulating cooling medium. The distal end of the coaxial connector 11 is adapted to the proximal end of the second water tank 10 and forms a blockage. The coaxial cable is electrically connected to the corresponding terminal in the coaxial connector 11.

[0077] In the technical solution of this embodiment, the outer wall of the ablation needle outer tube 1 is sealedly connected to the first water tank 9, so that the cavity surrounded by the outer tube 1 and the inner tube 2 is connected to the first water tank 9; the distal end of the second water tank 10 is adapted to the proximal end of the first water tank 9 and forms a blockage, so that the first water tank 9 is sealed; the outer wall of the ablation needle inner tube 2 is sealedly connected to the second water tank 10, so that the cavity surrounded by the inner tube 2 and the coaxial cable is connected to the second water tank 10; the distal end of the coaxial connector 11 is adapted to the proximal end of the second water tank 10 and forms a blockage, so that the second water tank 10 is sealed, thereby forming: the first water tank 9—the cavity surrounded by the outer tube 1 and the inner tube 2—the connecting hole 201—the cavity surrounded by the inner tube 2 and the coaxial cable 3—the circulating cooling path of the second water tank 10, or forming: the second water tank 10—the cavity surrounded by the inner tube 2 and the coaxial cable 3—the connecting hole 201—the cavity surrounded by the outer tube 1 and the inner tube 2—the circulating cooling path of the first water tank 9. The coaxial cable is electrically connected to corresponding terminals within the coaxial connector 11 to power the ablation needle. One advantage of this embodiment is that the first water tank 9 and the second water tank 10 utilize the same structure and dimensions, facilitating production and processing, thereby improving production efficiency and convenience. Specifically, the connection between the outer wall of the outer tube 1 and the first water tank 9, and the connection between the outer wall of the inner tube 2 and the second water tank 10, can be achieved by gluing, filling, or any other conventional connection method.

[0078] In the technical solution of this embodiment, the first water tank 9, the second water tank 10, and the coaxial connector 11 are coaxially arranged along the length extension direction of the outer tube 1, which can avoid bending of the coaxial cable 3 and avoid electromagnetic mutation caused by uneven bending curvature during production, thereby affecting microwave transmission.

[0079] Preferably, the present invention further provides an ablation assembly, which includes any one of the above-mentioned microwave ablation needles.

[0080] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they still fall within the scope of protection of the present invention.

Claims

1. A microwave ablation needle, characterized in that: include: An outer tube, an inner tube, a coaxial cable and a connector for coaxially and fixedly connecting the coaxial cable to the outer tube, wherein the connector is sealedly connected to the inner wall of the outer tube and the outer wall of the coaxial cable to form a circulating cooling passage through the gap between the outer tube and the inner tube, and the gap between the inner tube and the coaxial cable; In a plane perpendicular to the direction in which the ablation needle extends in length, the outer tube and the inner tube form a first flow cross section, the inner tube and the coaxial cable form a second flow cross section, and the difference between the area of ​​the first flow cross section and the area of ​​the second flow cross section is within a preset threshold range; During the microwave ablation process, the cooling medium is cooled through the circulating cooling passage to achieve pressure balance of the cooling medium through the first flow cross section and the second flow cross section.

2. The microwave ablation needle according to claim 1, characterized in that: The ablation needle also includes a puncture and ablation portion, which includes a needle head axially fixedly connected to the coaxial cable, the distal end of the needle head has a spike, and the proximal end of the needle head is fixedly connected to the distal end of the inner conductor of the coaxial cable. The coaxial cable includes an inner conductor, an outer conductor and a dielectric, and a radiation window is formed between the distal end of the outer conductor of the coaxial cable and the proximal end of the needle head, and the distal end of the dielectric abuts against the proximal end surface of the needle head. When the ablation process is started, the needle head serves as an antenna of the inner conductor, wherein the distal end of the inner conductor of the coaxial cable protrudes from the distal end of the coaxial cable dielectric, and the distal end of the coaxial cable dielectric protrudes from the distal end of the outer conductor of the coaxial cable.

3. The microwave ablation needle according to claim 2, characterized in that: The puncture and ablation part also includes a conductive component covering the radiation window, which is a tubular structure and is sleeved to cover the radiation window. The needle includes a needle body and an annular connector arranged on the proximal surface of the needle body. The inner ring surface of the annular connector is fixedly connected to the inner conductor, the outer ring surface of the annular connector is connected to the inner wall of the conductive component, the proximal surface of the annular connector is the proximal surface of the needle, and the two ends of the conductive component are respectively abutted against the distal surface of the outer tube and the proximal surface of the needle body.

4. The microwave ablation needle according to claim 3, characterized in that: The needle is made of metal, and the inner conductor and the annular connector are connected by a crimping process.

5. The microwave ablation needle according to claim 3, characterized in that: The conducting component is made of high thermal conductivity ceramic material, and there are micro gaps between the two ends of the conducting component and the distal end surface of the outer tube and the proximal end surface of the needle body. The outer surfaces of the outer tube and the conducting component have polytetrafluoroethylene insulation layers.

6. The microwave ablation needle according to claim 2, characterized in that: The distance L between the radiation window and the proximal end of the ablation needle is (2n+1)*λ / 4, wherein n represents a positive integer, and λ represents the wavelength of the electromagnetic wave when it is transmitted in the coaxial cable.

7. The microwave ablation needle according to claim 2, characterized in that: The microwave ablation needle further includes a thermocouple, which extends along the length direction of the microwave ablation needle and is disposed in a cavity formed by the inner tube and the coaxial cable, or in a cavity formed by the outer tube and the inner tube.

8. The microwave ablation needle according to claim 1, characterized in that: The distal end surface of the inner tube abuts against the proximal end surface of the connector, and a plurality of connecting holes are provided on the side wall of the distal end of the inner tube. During the ablation and cooling process, the cooling medium forms a circulating cooling passage through the first flow section, the connecting holes and the second flow section.

9. The microwave ablation needle according to claim 1, characterized in that: The outer tube is made of metal, the connecting piece is a magnetic ring or a copper ring, and the distal end surface of the inner tube is welded to the connecting piece. or, The connecting piece is made of non-metallic material, a balun is arranged on the connecting piece, and the distal end surface of the inner tube is fixedly connected to the connecting piece.

10. The microwave ablation needle according to claim 9, characterized in that: The microwave ablation needle also includes a first water tank, a second water tank and a coaxial connector arranged along the length extension direction of the outer tube. The microwave ablation needle passes through the first water tank and the second water tank. The proximal end surface of the outer tube of the ablation needle is welded to the first inlet of the first water tank. The inner tube of the ablation needle passes through and is welded to the first outlet of the first water tank. The proximal end surface of the inner tube is welded to the second inlet of the second water tank. The proximal end of the coaxial cable passes through and is sealed and connected to the second outlet of the second water tank. The first water tank and the second water tank are respectively provided with a connecting port for circulating cooling medium. The coaxial cable is electrically connected to the corresponding terminal in the coaxial connector.

11. The microwave ablation needle according to claim 9, characterized in that: The microwave ablation needle also includes a first water tank, a second water tank and a coaxial connector arranged along the length extension direction of the outer tube. The microwave ablation needle passes through the first water tank and the second water tank. The distal end of the second water tank is adapted to the proximal end of the first water tank to form a blockage. The proximal end of the outer tube of the ablation needle extends to the inner cavity of the first water tank. The outer wall of the outer tube is sealed with the first water tank. The proximal end of the inner tube of the ablation needle extends to the inner cavity of the second water tank. The outer wall of the inner tube is sealed with the second water tank. The first water tank and the second water tank are respectively provided with a connecting port for circulating cooling medium. The distal end of the coaxial connector is adapted to the proximal end of the second water tank to form a blockage. The coaxial cable is electrically connected to the corresponding terminal in the coaxial connector.

12. An ablation system component characterized by: A microwave ablation needle comprising any one of claims 1 to 11.

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