Microwave ablation needle without cooling structure

Abstract

This invention belongs to the field of medical device technology and mainly provides a microwave ablation needle without a cooling structure. It includes a cable with a coating on its outer surface to block the reverse transmission of microwaves from the outer wall. A needle is connected to the front end of the cable, and an radio frequency (RF) connector is connected to the rear end. The RF connector is used to connect to a microwave source that intermittently outputs microwaves. An outer tube is fitted over the cable, and a heat insulation component is fixed between the needle and the outer tube to prevent heat conduction to the outer tube. This invention suppresses microwave-induced heat generation on the cable's outer wall through the coating, and the heat insulation component blocks the axial transmission of high temperature from the needle. Combined with intermittent microwave output for coordinated temperature control, it eliminates the need for water-cooling or air-cooling external cooling structures. The temperature of the outer tube can be controlled below 45°C, and the needle temperature can be stably maintained within the treatment range of 60°C to 100°C, effectively inactivating tumor cells while preventing tissue carbonization. This invention eliminates the risks of tubing leakage, needle corrosion and aging, reduces the needle diameter, and has a simple structure and low production cost.

Description

Technical Field

[0001] This invention belongs to the field of medical device technology, and in particular relates to a microwave ablation needle without a cooling structure. Background Technology

[0002] Microwave ablation relies on high-frequency microwaves to generate heat through friction between polar molecules within the lesion tissue, heating the tissue to above 60°C to induce irreversible coagulative necrosis, thereby inactivating the tumor. Compared to traditional surgery, microwave ablation offers advantages such as smaller incision size, lower invasiveness, shorter recovery period, weaker intraoperative stress response, lower pain levels, and the ability to preserve some normal thyroid tissue. It has been included in numerous clinical guidelines and treatment consensus statements, and its clinical application continues to expand.

[0003] Currently, most mainstream clinical microwave ablation needles are equipped with water-cooled or air-cooled external cooling structures. These needles have several inherent drawbacks. Cooling tubing poses risks of water and air leakage; the connection between the tubing and the needle tip is prone to needle detachment or tip breakage; prolonged contact between the cooling medium and internal metal components accelerates oxidation and corrosion, shortening the device's lifespan; the cooling tubing occupies internal space, resulting in a larger overall needle diameter; the tubing structure can also interfere with the doctor's operation, reducing puncture accuracy and operational stability; and the presence of cooling channels can alter the microwave radiation field distribution, causing irregular ablation patterns. To overcome these drawbacks, the industry is gradually developing microwave ablation needles without external cooling structures.

[0004] Patent document CN211024824U discloses a water-cooling-free microwave ablation needle for tumors. Its structure includes a puncture head, an inner conductor, an insulating sleeve, a metal outer sleeve, and an insulating bushing. Electrical isolation between the puncture head and the metal outer sleeve is achieved through the insulating bushing, and operation without cooling relies on the heat conduction of the metal components themselves. However, this solution only relies on the front insulating bushing to block direct heat conduction between the puncture head and the metal outer sleeve, without any suppression structure for microwaves propagating backward along the outer wall of the coaxial cable. During ablation, the stripping structure at the end of the coaxial cable induces microwaves to propagate backward along the outer surface of the outer conductor. These reverse microwaves continuously generate Joule heat on the outer wall of the outer conductor. The front insulation structure alone cannot suppress the temperature rise of the needle rod along the cable's outer wall. The rod temperature can only be barely controlled under low power and short-duration conditions; under high power and long-duration ablation, the needle rod temperature easily exceeds the safety threshold. Furthermore, this solution only supports continuous microwave output and cannot balance heat generation through intermittent heat dissipation, resulting in a low temperature control upper limit and limiting the applicable clinical ablation power and treatment duration.

[0005] Patent document CN2838555Y discloses a high-strength rodless microwave ablation needle. This design adds a heat insulation component to the outer wall of the outermost needle tube and optimizes the dimensions of the inner conductor and emitter to reduce the standing wave ratio, thereby alleviating the needle rod's overheating problem. However, this design's heat insulation component, located on the outer surface of the outer needle tube, only blocks heat transfer from the needle rod to external human tissue. It cannot suppress the reverse microwave induction heat generation on the outer wall of the coaxial cable's outer conductor, and the internal heat source of the needle rod is not fundamentally controlled. Furthermore, this design lacks a dedicated shielding structure to block reverse microwaves and also lacks dynamic heat dissipation control logic. Relying solely on the outer heat insulation structure cannot reduce the heat continuously generated by the cable's outer wall. Under prolonged ablation conditions, heat continues to accumulate inside the needle rod, resulting in significant limitations in temperature control.

[0006] Based on the two existing technologies, it is clear that current uncooled ablation needles only alleviate the problem of rod temperature rise through a single approach, such as front-end insulation or outer wrapping with heat-insulating material. A single heat-insulating structure cannot simultaneously address the two major sources of temperature rise: reverse microwave heat generation from the cable's outer wall and high-temperature axial conduction from the needle tip. After eliminating external water-cooling and air-cooling structures, it is difficult to simultaneously achieve the dual goals of stabilizing the needle rod temperature within a safe threshold and maintaining the needle tip within an effective ablation temperature range. Therefore, it cannot balance the safety of needle rod temperature control with the effectiveness of tumor ablation treatment, exhibiting significant technical deficiencies. Summary of the Invention

[0007] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a microwave ablation needle without a cooling structure, so as to solve the problem that it is difficult to achieve both needle bar temperature control and ablation effect after eliminating external cooling in the prior art.

[0008] To achieve the above and other related objectives, the present invention provides a microwave ablation needle without a cooling structure, comprising a cable, wherein the outer surface of the cable is provided with a coating for blocking the reverse transmission of microwaves on the outer wall of the cable, a needle is connected to the front end of the cable, and an radio frequency connector is connected to the rear end of the cable. The radio frequency connector is used to connect to a microwave source that outputs microwaves intermittently. An outer tube is sleeved on the outside of the cable, and a heat insulation component is fixedly connected between the needle and the outer tube to block heat conduction to the outer tube.

[0009] In some embodiments of the present invention, the cable is a coaxial cable, comprising an inner conductor, an insulation layer and an outer conductor from the inside out, and the plating layer is applied to the outer surface of the outer conductor.

[0010] In some embodiments of the present invention, the heat insulation component is sleeved on the outer periphery of the front end of the insulating layer, the front end of the heat insulation component is fixedly connected to the rear end of the needle, and the rear end of the heat insulation component is fixedly connected to the front end face of the outer tube.

[0011] In some embodiments of the present invention, the front end of the inner conductor extends out of the insulating layer and is fixedly connected to the needle, and the tail end of the inner conductor extends out of the insulating layer and is fixedly connected to the radio frequency connector.

[0012] In some embodiments of the present invention, the front end of the needle is tapered, and the rear end of the needle is connected to the front end of the cable.

[0013] In some embodiments of the present invention, the heat insulation component is made of polytetrafluoroethylene.

[0014] In some embodiments of the present invention, the diameter of the cable is 0.8 mm to 1.6 mm.

[0015] In some embodiments of the present invention, the coating material is any one of copper, tin, zinc, aluminum, gold, silver or an alloy thereof.

[0016] In some embodiments of the present invention, the outer tube is made of a high thermal conductivity metal.

[0017] In some embodiments of the present invention, the outer tube is arranged coaxially with the cable.

[0018] In some embodiments of the present invention, an annular non-metallic layer is further provided between the outer surface of the cable and the plating layer, and the annular non-metallic layer is electrically insulated from the cable.

[0019] As described above, the present invention has the following beneficial effects:

[0020] 1. The coating can block microwaves transmitted in the reverse direction along the outer wall of the cable, reduce the Joule heat generated by high frequency induction on the outer wall of the cable, and reduce the basic heat generation rate of the outer tube. The heat insulation component can block the high temperature heat generated by the needle radiating microwaves during operation from being conducted axially to the outer tube, further reducing the total amount of heat transferred to the outer tube. The two work together, in conjunction with the microwave source that outputs microwaves in an intermittent manner, and without eliminating external cooling structures such as water cooling and air cooling, the surface temperature of the outer tube can be stably maintained below 45°C, avoiding the situation where the outer tube burns the normal human tissue around the needle track during the ablation operation.

[0021] 2. The intermittent output mode can dynamically balance the heat generated by the needle tip and the natural heat dissipation of the outer tube, so that the needle tip temperature is kept stable in the treatment range of 60℃ to 100℃. The minimum temperature of 60℃ can cause irreversible coagulative necrosis of tumor cells, completing the ablation treatment of the lesion; the upper temperature limit of 100℃ can avoid carbonization of tissue in the ablation area, ensuring that the ablation range is uniform and controllable. Under the same power conditions, the ablation effect is better than that of traditional water-cooled ablation needles.

[0022] 3. The overall solution does not require supporting cooling pipes, cooling media and circulating cooling components, eliminating the risks of water and air leakage that exist in traditional ablation needles. At the same time, it avoids the problems of cooling pipe detachment and pipe corrosion accelerating equipment aging. There is no need to lay cooling channels inside the outer tube, which can reduce the overall diameter of the outer tube and improve the accuracy and stability of the puncture operation. Attached Figure Description

[0023] Figure 1 The diagram shown is a schematic representation of the structure of the present invention.

[0024] Figure 2 The diagram shown is an exploded view of the present invention.

[0025] Figure 3 Shown as a front view of the present invention;

[0026] Figure 4 The view shown is an axial sectional view of the present invention.

[0027] Figure 5 Displayed as Figure 2 Enlarged view of point A in the middle;

[0028] Figure 6 Displayed as Figure 3 Enlarged view of point B in the middle;

[0029] Figure 7 Displayed as Figure 3 Enlarged view of point C in the middle;

[0030] Figure 8 The diagram shows the structure of the thermal insulation component.

[0031] Figure 9 The diagram shown is a temperature curve during the use of the present invention in Example 1.

[0032] Figure 10 The diagram shown is a comparison of the effects of the present invention and conventional water-cooled ablation at a power of 10W in Example 2.

[0033] Figure 11 The diagram shows a comparison between the 20W power of the present invention and the 40W power of conventional water-cooled ablation in Example 2.

[0034] Figure 12 The graph shows the temperature change of the outer tube over time in Example 3, where the outer conductor plating is tin plating.

[0035] Figure 13 The graph shows the temperature change over time for the outer tube of Example 3, where the outer conductor plating is copper plating.

[0036] Figure 14 This shows the temperature change over time for the outer tube of Example 3, where the outer conductor coating is zinc-plated.

[0037] Figure 15 The graph shows the change in the outer tube temperature as ablation time in Comparative Example 1.

[0038] Figure 16 The graph shows the change in the outer tube temperature as ablation time in Comparative Example 2.

[0039] Figure 17 The graph shown is a comparison of the change in the temperature of the outer tube over the ablation time.

[0040] Explanation of icon numbers:

[0041] 1. Needle; 2. Thermal insulation; 3. Cable; 4. Radio frequency connector; 5. Outer tube;

[0042] 21. Insertion section; 22. Isolation section;

[0043] 31. Inner conductor; 32. Insulating layer; 33. Outer conductor; 34. Plating. Detailed Implementation

[0044] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects 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 various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0045] Please see Figures 1-16 It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0046] like Figures 1-4 As shown, this invention provides a microwave ablation needle without a cooling structure, applicable to microwave ablation treatment of thyroid nodules, thyroid cancer, and other solid tumors. The microwave ablation needle without a cooling structure is an elongated rod-shaped structure, comprising, from front to back along the axial direction, a needle tip 1, a heat insulation component 2, a cable 3, and a radio frequency connector 4. An outer tube 5 is fitted onto the cable 3, and the front end of the cable 3 is connected to the needle tip 1. The heat insulation component 2 is fitted onto the front end of the cable 3 and is positioned between the needle tip 1 and the outer tube 5, forming a fixed connection with both the needle tip 1 and the outer tube 5. The radio frequency connector 4 is located at the rear end of the outer tube 5 and connects to the rear end of the cable 3.

[0047] like Figures 5-7As shown, in this embodiment, cable 3 is a coaxial cable. Cable 3 comprises, from the inside out, an inner conductor 31, an insulation layer 32, and an outer conductor 33. The inner conductor 31 is located at the center of cable 3 and is used to transmit microwave energy. The insulation layer 32 covers the outer periphery of the inner conductor 31, achieving electrical isolation between the inner conductor 31 and the outer conductor 33. The outer conductor 33 covers the outer periphery of the insulation layer 32, forming a shielding structure for microwave transmission. The outer surface of the outer conductor 33 is provided with a plating layer 34, which can suppress microwave energy transmitted in the reverse direction along the outer wall of cable 3 and reduce the heat generated by microwave induction in the corresponding area of ​​the outer tube 5.

[0048] The front end of cable 3 undergoes end stripping. The outer conductor 33 at the front end is stripped, exposing the insulation layer 32 with an axial length of 2mm to 10mm. The inner conductor 31 at the front end of the insulation layer 32 is further exposed, with an axial length of 1mm to 4mm. The front end of the exposed inner conductor 31 is fixedly connected to the center of the rear end of the needle 1, allowing microwave energy to be directly transmitted from the inner conductor 31 to the needle 1, and then radiated from the needle 1 to the surrounding tissue.

[0049] The end of cable 3 is also stripped. The outer conductor 33 at the end is stripped, exposing the insulation layer 32 with an axial length of 2mm to 3mm. The inner conductor 31 at the end of the insulation layer 32 is further exposed, with an axial length of 2mm to 3mm. The exposed end of the inner conductor 31 is fixedly connected to the internal contact of the RF connector 4, so that the energy output from the microwave source can be transmitted to the inner conductor 31 of cable 3 via the RF connector 4.

[0050] The tip of needle 1 is tapered, which reduces puncture resistance and facilitates the microwave ablation needle's percutaneous insertion into the target tumor tissue area. The exposed tip of the inner conductor 31 is inserted into and fixed within needle 1. As the microwave radiating end, needle 1 radiates the microwave energy transmitted by the inner conductor 31 into the surrounding tissue space, exciting polar molecules within the tissue to generate high-speed vibration and friction, thereby raising the tissue temperature.

[0051] like Figure 8 As shown, the heat insulation component 2 includes an insertion part 21 and an isolation part 22 fixedly connected together. The insertion part 21 is inserted between the insulating layer 32 and the outer tube 5, that is, the insertion part 21 is sleeved on the exposed insulating layer 32. The isolation part 22 is located between the outer tube 5 and the needle 1, and the isolation part 22 is also sleeved on the exposed insulating layer 32. The heat insulation component 2 is made of a low thermal conductivity material, which can form an axial thermal resistance between the needle 1 and the outer tube 5. When the heat generated by the needle 1 during operation is conducted axially towards the needle tail, it will be blocked by the heat insulation component 2, reducing the heat transferred to the outer tube 5 through the axial conduction path and reducing the temperature rise rate of the outer tube 5.

[0052] In this embodiment, the heat insulation component 2 is made of polytetrafluoroethylene (PTFE). PTFE has stable chemical properties and a low thermal conductivity, which allows it to maintain the connection strength between the needle 1 and the outer tube 5 while achieving thermal barrier properties. This material can withstand the temperature range during the ablation process and will not experience performance degradation due to temperature fluctuations.

[0053] In this embodiment, the outer tube 5 is made of a high thermal conductivity metal. High thermal conductivity metals have a high thermal conductivity coefficient. During the operation of the microwave ablation needle, the high thermal conductivity metal material can accelerate the rate of heat dissipation, shorten the cooling time during the microwave output stop phase, and help achieve stable temperature control under conditions without external cooling.

[0054] The radio frequency connector 4 is located at the tail end of the entire microwave ablation needle. The exposed insulating layer 32 and inner conductor 31 are inserted into and secured into the radio frequency connector 4. The radio frequency connector 4 is used to connect a microwave source that outputs microwaves intermittently.

[0055] In this embodiment, the plating layer 34 is made of copper. The copper plating layer 34 has good electrical conductivity and can form a continuous conductive shielding layer on the outer surface of the outer conductor 33. This shielding layer can reflect and block microwaves that are transmitted in the reverse direction along the outer wall of the outer conductor 33, reducing the microwave energy acting on the outer tube 5 region and reducing the microwave induced heat generation of the outer tube 5.

[0056] In another embodiment, the plating layer 34 is made of any one of tin, zinc, aluminum, gold, or silver, or an alloy thereof. A tin plating layer 34 can be uniformly adhered to the outer surface of the outer conductor 33 using conventional surface treatment processes, forming a dense conductive layer. The tin plating layer 34 can also block microwaves propagating in the reverse direction along the outer wall of the cable 3, controlling the temperature rise of the outer tube 5. A zinc plating layer 34 has good adhesion properties and can form a stable bond with the surface of the outer conductor 33. The zinc plating layer 34 can shield microwaves propagating in the reverse direction, reducing heat generation in the area of ​​the outer tube 5. All of the above-mentioned plating layers 34 can form a conductive shielding structure on the outer surface of the outer conductor 33, achieving the function of blocking reverse microwaves. Combined with the intermittent microwave control method, this meets the temperature control requirements under conditions without cooling.

[0057] The diameter of cable 3 ranges from 0.8 mm to 1.6 mm. This diameter range of cable 3 is suitable for the internal space design of fine-diameter microwave ablation needles. Combined with the structure without external cooling pipes, the outer diameter of the entire outer tube 5 of the microwave ablation needle can be controlled, achieving a reduction in the overall diameter of the needle body. The finer needle body can reduce the puncture wound and minimize damage to surrounding normal tissues.

[0058] In another embodiment, an annular non-metallic layer is provided between the outer surface of the cable 3 and the plating layer 34, and the annular non-metallic layer is electrically insulated from the cable 3.

[0059] When using the aforementioned microwave ablation needle without a cooling structure, first connect the radio frequency connector 4 to the external microwave source output interface. The operator holds the tail of the needle, aligns the needle tip 1 with the target tissue location, and advances the needle along the puncture path until the needle tip 1 reaches the preset tumor ablation area. During the puncture, the metal outer tube 5 maintains the straight shape of the needle, ensuring the accuracy of the puncture path.

[0060] This microwave ablation needle without a cooling structure eliminates the need for external cooling pipes and a corresponding cooling system. There is no need for water-cooled or air-cooled channels inside the needle, eliminating the risk of water or air leakage. The absence of cooling pipe connections at the needle tip reduces the probability of needle tip detachment. The absence of cooling channels also prevents oxidation and corrosion of internal components due to prolonged contact with coolant, thus slowing down the aging process of the equipment.

[0061] In this embodiment, after the microwave source is activated, it outputs microwave energy intermittently. The microwave energy enters the inner conductor 31 of the cable 3 via the radio frequency connector 4 and is transmitted forward along the inner conductor 31 to the needle tip 1. The needle tip 1 radiates microwave energy to the surrounding tumor tissue, causing the polar molecules within the tissue to vibrate at high speed with the microwave electric field. The friction of molecular vibration generates heat, causing the temperature of the tissue around the needle tip 1 to gradually rise. During this stage, heat continuously accumulates in the area of ​​the needle tip 1, and the temperature gradually increases.

[0062] When the microwave source stops outputting microwaves, no more heat is generated in the needle tip 1 area. The heat inside the needle body is dissipated to the surrounding environment through the metal outer tube 5, and the temperature of the needle tip 1 and the outer tube 5 gradually decreases. During this stage, the heat insulation component 2 continuously blocks the axial transfer of heat from the needle tip 1 to the outer tube 5, and the coating 34 continuously maintains a shielding state that blocks reverse microwaves.

[0063] The microwave source cycles through output and stop actions according to a preset intermittent mode. During the output phase, the tissue generates heat and heats up; during the stop phase, the needle body dissipates heat and cools down. After the system stabilizes, the average duty cycle of the intermittent output is 38%. The output waveform of the microwave source can be a square wave or a sine wave. During continuous cyclic operation, the temperature of needle 1 is maintained between 60℃ and 100℃, and the surface temperature of the outer tube 5 is maintained below 45℃.

[0064] Example 1: Calculation of duty cycle of intermittent wave.

[0065] An NTC thermistor NTC1 is inserted parallel to the tip 1 of the microwave ablation needle, 0.5-1mm away, to monitor the temperature of the tip 1. Another NTC thermistor NTC2 is fixed to the surface of the microwave ablation outer tube 5, 1-2cm away from the tip of the microwave ablation needle, to monitor the temperature of the outer tube 5. The two NTC thermistors are connected to a circuit board, and the microwave output is controlled by the feedback temperature of the thermistors. When the temperature of thermistor NTC1 is ≤60℃ and the temperature of NTC2 is <45℃, microwave output occurs; when the temperature of thermistor NTC1 is ≥100℃ or the temperature of NTC2 is ≥45℃, microwave output stops. The test data is stored on an SD card. After exporting, the intermittent wave duty cycle is calculated to be 38% based on the temperature rise and fall intervals (e.g., ...). Figure 9 (As shown).

[0066] This embodiment employs a dual-temperature-point feedback method to control the microwave output state. Experiments calibrated the output parameters for stable operation of the ablation system under conditions without external cooling, verifying that the dual-temperature-threshold closed-loop control method can dynamically balance the heat generation and dissipation of the needle, providing a quantitative basis for the control logic of the cooling-free scheme.

[0067] Example 2:

[0068] This embodiment tests the ablation effect of a microwave ablation needle without a cooling structure. The test uses an intermittent output mode with a duty cycle of 38%.

[0069] Under test conditions of 10W output power and 5 minutes of operation, the ablation zone had a major diameter of 1.8cm and a minor diameter of 1.2cm. Under the same power and duration conditions, the ablation zone of a traditional water-cooled ablation needle had a major diameter of 1.5cm and a minor diameter of 0.7cm (e.g., ...). Figure 10 (As shown).

[0070] Under test conditions of 20W output power and 10 minutes of operation, the ablation zone had a major axis of 3.2cm and a minor axis of 2cm. For the same test duration, this ablation range is comparable to that of a traditional water-cooled ablation needle with continuous 40W output (e.g., ...). Figure 11 (As shown). No tissue carbonization was observed within the ablation area in this embodiment.

[0071] This embodiment verifies that a microwave ablation needle without a cooling structure can reach the corresponding ablation treatment range in intermittent output mode, and there is no tissue carbonization within the ablation area.

[0072] Example 3:

[0073] In this embodiment, a microwave ablation needle with a metal plating layer 34 on the surface of the outer conductor 33 is used for testing. During the test, the microwave source adopts an intermittent output mode with a duty cycle of 38%, and there is no external cooling system throughout the process.

[0074] This embodiment tests three plating materials: tin plating 34, copper plating 34, and zinc plating 34. The test results show that under all three plating 34 options, the temperature of the microwave ablation needle outer tube 5 can be stably controlled below 45℃. The temperature change of the outer tube 5 is shown below. Figure 12 , Figure 13 and Figure 14 As shown.

[0075] This embodiment verifies that when various common metal materials are used as the plating layer 34 of the outer conductor 33, they can all be used in conjunction with the intermittent output mode to achieve temperature control of the outer tube 5 under no-cooling conditions.

[0076] Comparative Example 1:

[0077] In this embodiment, an ablation needle without a plating layer 34 on the surface of the outer conductor 33 was used for comparative testing. During the test, the microwave source adopted continuous wave output mode, and there was no external cooling system throughout the process.

[0078] Test results show that under both 10W and 20W output power conditions, the temperature of the outer tube 5 of the ablation needle continuously increases with working time. Under the 20W output power condition, the temperature of the outer tube 5 can reach 82℃ to 90℃. The change in temperature of the outer tube 5 with ablation time is as follows: Figure 15 As shown.

[0079] This embodiment serves as a blank control condition, demonstrating the basic temperature rise level without cooling ablation needles when no coating 34 is set and continuous output is used.

[0080] Comparative Example 2:

[0081] In this embodiment, a microwave ablation needle without a plating layer 34 on the surface of the outer conductor 33 was used for comparative testing. During the test, the microwave source adopted an intermittent output mode with a duty cycle of 38%, and there was no external cooling system throughout the process.

[0082] Test results show that under both 10W and 20W output power conditions, the temperature of the outer tube 5 of the microwave ablation needle is above 45℃. Under the 20W output power condition, the highest temperature of the outer tube 5 is approximately 72℃. The temperature change of the outer tube 5 with ablation time is shown below. Figure 16 As shown.

[0083] This embodiment verifies that using only the intermittent output mode is insufficient to control the temperature of the outer tube 5 within the preset safety threshold range.

[0084] Comparative Example 3:

[0085] In this embodiment, a microwave ablation needle with a metal plating layer 34 on the surface of the outer conductor 33 is used for comparative testing. During the test, the microwave source adopts continuous wave output mode, and there is no external cooling system throughout the process.

[0086] Test results show that under both 10W and 20W output power conditions, the temperature of the outer tube 5 of the microwave ablation needle is above 45℃. Under the 20W output power condition, the temperature of the outer tube 5 is between 70℃ and 78℃. The temperature change of the outer tube 5 with ablation time is shown below. Figure 17 As shown.

[0087] This embodiment verifies that using only the outer conductor 33 and the plating layer 34 structure is insufficient to control the temperature of the outer tube 5 within the preset safety threshold range.

[0088] As can be seen from the above embodiments and comparative examples, the outer conductor 33 plating layer 34 structure, in conjunction with the intermittent output mode, can control the temperature of the microwave ablation needle outer tube 5 within a safe threshold without an external cooling system, while maintaining the needle tip 1 temperature within the treatment temperature range. Neither the plating layer 34 structure nor the intermittent output mode alone can achieve the corresponding temperature control effect.

[0089] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A microwave ablation needle without a cooling structure, characterized in that, The cable (3) includes a coating (34) on its outer surface for blocking the reverse transmission of microwaves from the outer wall of the cable (3). A needle (1) is connected to the front end of the cable (3), and an RF connector (4) is connected to the rear end of the cable (3). The RF connector (4) is used to connect to a microwave source that outputs microwaves intermittently. An outer tube (5) is fitted around the cable (3). A heat insulation component (2) is fixedly connected between the needle (1) and the outer tube (5) to block heat from being conducted to the outer tube (5).

2. The microwave ablation needle without cooling structure according to claim 1, characterized in that, The cable (3) is a coaxial cable, which includes an inner conductor (31), an insulation layer (32) and an outer conductor (33) from the inside to the outside. The plating layer (34) is applied to the outer surface of the outer conductor (33).

3. The microwave ablation needle without cooling structure according to claim 2, characterized in that, The heat insulation component (2) is sleeved on the outer periphery of the front end of the insulation layer (32). The front end of the heat insulation component (2) is fixedly connected to the rear end of the needle (1), and the rear end of the heat insulation component (2) is fixedly connected to the front end face of the outer tube (5).

4. The microwave ablation needle without a cooling structure according to claim 2, characterized in that, The front end of the inner conductor (31) extends out of the insulating layer (32) and is fixedly connected to the needle (1), and the tail end of the inner conductor (31) extends out of the insulating layer (32) and is fixedly connected to the radio frequency connector (4).

5. The microwave ablation needle without cooling structure according to claim 1, characterized in that, The front end of the needle (1) is tapered, and the rear end of the needle (1) is connected to the front end of the cable (3).

6. The microwave ablation needle without cooling structure according to claim 1, characterized in that, The heat insulation component (2) is made of polytetrafluoroethylene.

7. The microwave ablation needle without cooling structure according to claim 2, characterized in that, The diameter of the cable (3) is 0.8 mm to 1.6 mm.

8. The microwave ablation needle without cooling structure according to claim 1, characterized in that, The coating (34) is made of any one of copper, tin, zinc, aluminum, gold, silver or an alloy thereof.

9. The microwave ablation needle without cooling structure according to claim 1, characterized in that, The outer tube (5) is made of a high thermal conductivity metal.

10. The microwave ablation needle without cooling structure according to claim 1, characterized in that, An annular non-metallic layer is provided between the outer surface of the cable (3) and the plating layer (34), and the annular non-metallic layer is electrically insulated from the cable (3).

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