A high-power microwave ablation needle for lung tumors

Abstract

The application discloses a high-power microwave ablation needle for lung tumor, which comprises a bipolar microwave antenna and a matching liquid delivery pipe sleeved on the antenna. The radiation electrode of the antenna is a metal needle tip with high mechanical strength, and the reflection electrode is protected by a hard ceramic sleeve pipe, which is filled with cooling water to improve the matching performance and power tolerance of the microwave antenna. The matching liquid delivery pipe forms a matching liquid delivery channel between the metal needle shaft and the dielectric tube for delivering matching liquid to the central position of the ablation area to adjust the impedance matching of the radiation electrode. The matching liquid can reduce the temperature of the radiation electrode of the antenna, adjust the matching of the antenna radiation electrode, and thus reduce the risk of carbonization of the ablation area due to high temperature. On the other hand, the matching liquid injected into the central area of the ablation can significantly improve the thermal shrinkage of the surrounding lung tissue, and avoid excessive microwave reflection of the shrunk lung tissue.

Description

Technical Field

[0001] The invention relates to a high-power microwave ablation needle for lung tumors, belonging to the technical field of microwave ablation needles. Background Art

[0002] Microwave ablation utilizes the biophysical effects of microwaves to coagulate and inactivate tumor tissue at an instantaneous high temperature, achieving the goal of tumor ablation therapy. Electromagnetic waves in the microwave band cause polar molecules to vibrate and rotate, generating friction and heat. Microwave tumor ablation is characterized by high efficiency, rapidity, and concentrated energy. Microwave ablation involves inserting a microwave ablation needle into the target tissue. A microwave antenna at the tip of the needle transmits microwave energy at a frequency of 2450 MHz to perform the procedure. This procedure results in minimal incision, a highly conformable ablation zone, and controllable size, making it suitable for ablation of solid tumors.

[0003] In recent years, microwave tumor ablation technology has gained increasing recognition worldwide. This safe, effective, and minimally invasive tumor treatment method has become widely used. The widespread use of microwave ablation needles, as evidenced by the following patents, has significantly improved their applicability, power tolerance, and true circularity of the ablation zone. Their use has also expanded from ultrasound environments to magnetic resonance imaging (MRI) environments, making this series of ablation needles a dominant force in the market. These key patents include: A Water-Cooled Microwave Ablation Needle Antenna (CN 103006321 A, 2013); A Method for Manufacturing a Non-Magnetic Water-Cooled Microwave Ablation Needle (WO 2016074344A1, 2016); A True Circular Microwave Ablation Antenna and System (WO 2018 / 192325Al, 2018); and a Microwave Ablation Needle (US 11786303 B2, 2023). However, these microwave ablation needles have the following shortcomings in clinical use, particularly for the ablation treatment of early-stage lung tumors:

[0004] 1. Due to the size limitation of the microwave ablation needle, the metal structure of the antenna inside the ablation needle is very small and its surface electric field is extremely high. When the input microwave power is high, there is a risk of breakdown and sparking, causing damage to the fragile antenna structure.

[0005] 2. The microwave antenna is immersed in cooling water, and the electromagnetic field radiated by the antenna propagates outward through the water surrounding the antenna. Due to the extremely high absorption capacity of water for electromagnetic waves, the water-cooled antenna has high self-loss.

[0006] 3. Because the radiating antenna is designed for use in a water-saturated environment, the antenna system's microwave circuit exhibits excellent impedance matching, low reflection coefficient, and minimal standing wave response when connected to a water load. However, during microwave ablation, changes in the target tissue's water content and the contraction of the lung tissue caused by heating cause the lung tissue to deform, forming a dense, eggshell-like structure surrounding the microwave needle tip. This disrupts microwave matching and significantly reduces the performance of the microwave ablation needle in ablating non-solid lung tumors. At the beginning of the ablation procedure, the tissue water content is highest. As the ablation time increases, the temperature in the center of the ablation zone rises above the boiling point of water, causing water vapor to evaporate, the tissue water content to decrease, and the alveolar tissue, the main structure of the lung, to collapse. The contraction of the lung tissue envelops the antenna system in a dense, water-free sheath, resulting in poor impedance matching and reduced antenna radiation efficiency. This ultimately leads to excessive needle shaft temperature, severe structural damage and deformation in the central region, and reduced microwave radiation in the surrounding lung tissue.

[0007] 4. Due to the excessively high operating temperature of the needle tip, the tissue in the center of the ablation area is carbonized, causing the microwave needle tip to adhere to the tissue. This makes it difficult to withdraw the microwave needle after the ablation procedure, and in severe cases, it can lead to medical accidents such as needle breakage. Therefore, it is imperative to add new matching measures.

[0008] The Institute discovered that Chinese utility model patent CN 203829040 U discloses an injectable microwave needle antenna for tumor ablation therapy. This antenna incorporates a capillary tube for injection within the water outlet, and a micropore connected to the capillary tube is located on the needle shaft near the radiator. Liquid is injected into the ablation area through the micropore, providing adjuvant therapy. The injection of liquid also cools the ablation area and adjusts the impedance matching of the radiator to a certain extent. However, this design suffers from drawbacks: the micropores in the needle shaft reduce its strength, increasing the risk of breakage. Since microwave needles used for lungs are generally smaller in diameter, this perforated structure is particularly problematic in smaller-diameter lung-specific microwave ablation antennas. Furthermore, the small micropore diameter prevents the injected liquid from flowing through the antenna to meet the actual impedance matching requirements. However, increasing the micropore diameter to increase the injection flow rate further reduces needle shaft strength. This presents an irreconcilable contradiction. Summary of the Invention

[0009] The purpose of the present invention is to address the deficiencies of the above-mentioned prior art and provide a high-power microwave ablation needle for lung tumors. Matching liquid is delivered through a matching liquid delivery tube arranged outside the needle shaft, thereby achieving a large flow of matching liquid to the central ablation area without affecting the strength of the needle shaft.

[0010] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: a high-power microwave ablation needle for lung tumors, comprising a metal radiation head and a feeding coaxial cable, a cooling water pipe and a metal needle rod sequentially arranged from the inside to the outside, the inner conductor of the feeding coaxial cable being connected to the tail of the metal radiation head, and a first gap being formed between the outer conductor of the feeding coaxial cable and the tail of the metal radiation head as a radiation window of the antenna, characterized in that: a dielectric tube is arranged between the metal needle rod and the metal radiation head, the microwave ablation needle also has a matching liquid delivery tube arranged outside the metal needle rod and the dielectric tube, the outer diameter of the matching liquid delivery tube is not greater than the outer diameter of the metal radiation head, a second gap is formed between the matching liquid delivery tube and the metal needle rod and the dielectric tube as a matching liquid delivery channel, a third gap is formed between the front end of the matching liquid delivery tube and the metal radiation head, the third gap serves as an overflow annular groove for overflow of the matching liquid.

[0011] A matching fluid delivery channel is formed between the matching fluid delivery tube, the metal needle rod, and the dielectric tube, delivering matching fluid to the center of the ablation zone to adjust the impedance matching of the radiator. This matching fluid reduces the temperature of the antenna's radiator, adjusting its matching and thus reducing the risk of carbonization in the ablation zone caused by high temperatures. Furthermore, injection of matching fluid into the central ablation zone significantly reduces thermal shrinkage of the surrounding lung tissue, preventing excessive microwave reflection from the shrinking lung tissue.

[0012] The overflow annular groove formed by the matching liquid delivery tube and the metal radiation head of the present invention is annular, which can achieve a large flow output and meet the radiation pole impedance matching requirements in lung tumor ablation surgery. The annular gap can play a role in transporting liquid, but it is different from the previous additional delivery pipe inside the needle rod and the mode of punching holes at the needle tip, which has the following advantages. 1. The liquid is transported through the gap between the needle rod and the film, rather than through the pipeline occupying the internal space of the needle rod, reducing the impact on the cooling water circuit. 2. The liquid eventually seeps out to the surrounding of the needle rod through the gap between the film and the outer surface of the needle rod, without the need to punch holes on the surface of the needle rod, thereby improving the structural stability of the needle rod head.

[0013] Since the outer diameter of the matching liquid delivery tube is no larger than that of the metal radiation head, the presence of this gap does not affect the percutaneous puncture of the ablation needle. Compared with the prior art, the needle shaft of the present invention is not perforated, so its overall strength is higher and can meet surgical requirements.

[0014] The present invention designs the antenna's radiating electrode into an exposed metal tip and a partial needle body, utilizing moisture in the target tissue for impedance matching. The outer conductor of the feed coaxial cable serves as the antenna's reflector, and a rigid ceramic tube is installed on the outside of the reflector as a protective layer. Cooling water is introduced into the ceramic tube as a matching medium for the antenna's reflector. This microwave antenna exhibits excellent static impedance matching. To address the microwave impedance mismatch caused by high-temperature vaporization and dehydration of tissue surrounding the antenna's radiating electrode (metal tip) during the ablation process, the ablation needle of the present invention also provides a delivery conduit for releasing a matching fluid at the center of the ablation area. This fluid can be injected for dynamic matching when needed. Typically, physiological saline can be used as the matching fluid. This microwave needle is essentially a bipolar microwave antenna, significantly improving mechanical strength, circuit matching performance, power tolerance, and energy conversion efficiency.

[0015] The microwave needle contains a coaxial dipole antenna structure. The antenna's radiating element, formed by the metal tip of the microwave ablation needle, is matched and cooled by the moisture in the human tissue outside the needle. The antenna's reflector, formed by the outer conductor of the feed coaxial cable within the needle, is matched and cooled by the cooling water within the needle. To prevent carbonization of tissue contacting the metal tip during ablation, which could impair the matching performance of the microwave circuit, the microwave needle disclosed in this invention incorporates a liquid channel running through the radiating head. This channel allows for the release of matching liquid from the front of the needle to replenish the tissue outside the tip when needed. The matching liquid serves two purposes: improving the matching conditions of the microwave circuit and reducing the temperature at the needle tip. The metal tip is mounted on the top of a rigid ceramic tube, the other end of which is connected to the stainless steel needle shaft. The sealed interior of the ceramic tube is filled with circulating cooling water introduced through a plastic water pipe, which then drains out through the interior of the stainless steel needle shaft as a drainage channel. The feed coaxial cable is sealed within the ceramic tube, with its outer conductor acting as the antenna's reflector, which is matched and cooled by the cooling water. The microwave antenna structure has good impedance matching performance, mechanical strength and power tolerance. During the ablation process, as the temperature of the metal needle tip of the ablation needle rises, if no mitigating measures are taken, the high temperature of the needle tip will cause the moisture inside the surrounding tissue to vaporize and disappear, destroying the impedance matching conditions of the microwave antenna, increasing the reflection of the microwave antenna, increasing the standing wave coefficient, reducing the antenna performance and even burning the microwave antenna. The microwave needle disclosed in the present invention has a PTFE plastic water pipe coaxially installed outside the needle rod and the ceramic tube, and several water outlet holes are drilled near the metal needle to release the matching liquid into the target tissue. Most of the energy radiated by the antenna structure can enter the target tissue, with a high energy conversion efficiency.

[0016] The role of the matching liquid in the ablation area can be summarized into five aspects: (1) maintaining a good matching state of the microwave circuit; (2) reducing the central temperature of the ablation area and reducing the risk of tissue adhesion; (3) because microwave energy needs to be converted into heat through the action of the water medium, the temperature of the ablation center area decreases after dehydration and carbonization, and it cannot transmit high temperature to the surrounding tissues, reducing the ablation efficiency. Supplementing the matching liquid can avoid the temperature drop, reduce the temperature in the center of the ablation area, reduce the risk of tissue adhesion, and reduce the degree of thermal shrinkage of specific tissues (lung tissue) and reduce scarring. The continuous high temperature in the center area can transmit energy to the surrounding tissues, making the tissues in a larger range in a high temperature state, thereby expanding the ablation range; (4) because microwaves have the characteristic of increasing the propagation distance in a medium with higher temperature, in the higher temperature area, the microwave penetration distance increases, and the ablation range also increases. (5) The water in the matching liquid can be converted into water vapor under the stimulation of microwaves. In specific tissues (lung tissue), it has the ability to kill tumor cells in the alveoli. At the same time, water vapor can diffuse and expand in the lung tissue, and can be converted between the vapor and liquid phases, thereby increasing the range and effectiveness of tumor inactivation. Experiments have shown that the microwave antenna has a better ablation range than traditional microwave needles in animal models, while the tissue deformation and irreversible damage in the central area are lower. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described below with reference to the accompanying drawings.

[0018] Figure 1 It is a cross-sectional view of a microwave ablation needle according to an embodiment of the present invention.

[0019] Figure 2 It is a front-end cross-sectional view of a microwave ablation needle according to an embodiment of the present invention.

[0020] Figure 3 is a cross-sectional view of a microwave ablation antenna with a spherical tip.

[0021] Figure 4 is a cross-sectional view of a microwave ablation antenna with a parabola of rotation tip.

[0022] Figure 5 This is a comparison of He-stained microscopic images of sections after ablation in living rabbit lungs using a conventional microwave ablation needle and the microwave ablation needle of the present invention.

[0023] Figure 6 This is a comparison of CT images of scars after ablation in a living pig lung using a traditional microwave ablation needle and the microwave ablation needle of the present invention.

[0024] Figure 7 This is a comparison of thermal imaging of a traditional microwave ablation needle and the microwave ablation needle of the present invention in a living pig lung.

[0025] The numbers in the figure are as follows: 1-metal radiation head, 2-small hole, 3-matching liquid delivery tube, 4-metal needle rod, 5-dielectric tube, 6-inner conductor, 7-outer conductor, 8-plastic cooling water diversion pipe, 9-matching liquid inlet, 10-matching liquid cavity, 11-cooling water outlet, 12-water outlet cavity, 13-cooling water inlet, 14-water inlet cavity, 15-microwave connector; A-third gap. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] like Figure 1 As shown, the high-power microwave ablation needle for lung tumors includes a metal radiation head 1 and a feeding coaxial cable, a cooling water pipe 8 and a metal needle rod 4 which are sequentially arranged from the inside to the outside. The inner conductor 6 of the feeding coaxial cable is connected to the tail of the metal radiation head 1, and a first gap is formed between the outer conductor 7 of the feeding coaxial cable and the tail of the metal radiation head 1 as the radiation window of the antenna. The microwave radiation energy of the antenna is radiated outward through the radiation window. The metal radiation head 1 serves as the radiation pole of the antenna, and the outer conductor 7 of the feeding coaxial cable serves as the reflection pole of the antenna, thereby obtaining the dipole antenna of the present invention. Figure 1 As shown, a dielectric tube 5 is provided between the metal needle rod 4 and the metal radiation head 1, and the microwave energy of the antenna penetrates the dielectric tube and radiates outwards. In this embodiment, the dielectric tube 5 is a ceramic tube.

[0028] The microwave ablation needle also features a matching liquid delivery tube 3, which is sheathed around the metal needle shaft 4 and dielectric tube 5. A second gap is formed between the matching liquid delivery tube 3, the metal needle shaft 4, and the dielectric tube 5, serving as a matching liquid delivery channel. This matching liquid delivery tube is used to deliver matching liquid to the front end of the antenna and inject water into the radiation center. The outer diameter of the matching liquid delivery tube 3 is no larger than that of the metal radiating head 1, ensuring smooth puncture without creating additional resistance. In stark contrast to the prior art (which utilizes holes in the needle shaft to achieve overflow), this embodiment forms a third gap A between the front end of the matching liquid delivery tube 3 and the metal radiating head 1. This third gap A serves as an annular overflow groove for overflow of matching liquid. The front end of the matching liquid delivery tube 3 in this embodiment is not fixed; it is suspended in the air. The overflow annular groove ensures a high flow rate of matching liquid, quickly reducing the temperature at the front end of the antenna and instantly improving impedance matching. This allows the antenna to heat at a higher power, with a wider radiation range and shorter ablation time. The overflow annular groove also provides more uniform water flow, eliminating the risk of small holes becoming clogged. In this embodiment, the matching liquid delivery tube 3 is made of PTFE tube. In addition, a plastic tube coated with PTFE anti-stick coating can also be used. PTFE can prevent adhesion and make the needle easy to remove after surgery.

[0029] like Figure 1 As shown, the metal needle rod 4 has a matching liquid inlet chamber 10 with a matching liquid inlet port 9 at its rear, and a matching liquid delivery channel connected to the matching liquid inlet chamber 10. Matching liquid passes through the matching liquid inlet port 9, the matching liquid inlet chamber 10, and the matching liquid delivery channel in sequence to reach the front end of the antenna, where it is ejected toward the radiation center through the overflow annular groove (third gap A).

[0030] The front end of the cooling water supply pipe 8 extends to near the tail of the metal radiation head 1. The gap between the cooling water supply pipe 8 and the outer conductor 7 of the feeding coaxial cable forms a water inlet, and the gap between the cooling water supply pipe 8, the dielectric tube 5 and the metal needle rod 4 forms a water return. The rear part of the metal needle rod 4 is provided with a water inlet chamber 14 with a cooling water inlet 13 and a water outlet chamber 12 with a cooling water outlet 11. The water inlet is connected to the water inlet chamber 14, and the water return is connected to the water outlet chamber 12. The cooling water passes through the cooling water inlet 13, the water inlet chamber 14, and the water inlet in sequence to reach the front of the antenna, and then is discharged through the water return, the water outlet chamber 12, and the cooling water outlet 11 in sequence. The used cooling water can be connected to the cooling equipment for recycling, or it can be discharged directly without polluting the environment.

[0031] like Figure 1 As shown, the tail of the metal radiation head 2 has a cylinder, the front part of the dielectric tube 5 is sleeved and fixed on the cylinder, a protrusion is provided at the center of the tail of the cylinder, the front end of the inner conductor 6 of the feeding coaxial cable is riveted or welded to the protrusion, and the front end of the cooling water inlet pipe 8 is partially fixed to the protrusion.

[0032] To further increase the flow rate and coverage of the matching liquid, several small holes 2 are distributed circumferentially along the front of the matching liquid delivery tube 3, allowing the matching liquid to overflow. This improved solution primarily utilizes the overflow annular groove (at the third gap A), supplemented by the small holes 2. This achieves wider coverage of the matching liquid and enhances the impedance matching effect. Furthermore, the diameter and layout of the small holes 2 can be adjusted, increasing product development flexibility and enabling the selection of more targeted products based on the individual patient's lung tumor.

[0033] The inventors conducted a live rabbit lung ablation experiment. After the contrast agent was mixed with the matching fluid, the anatomy showed that the distribution of the matching fluid was completely consistent with the ablation zone. Comparison of HE staining and NADH staining after ablation in the live rabbits showed no significant difference in the size of the ablation zone, and the injection of the matching fluid did not change the size of the ablation zone. HE staining showed that the ablation range of steam microwaves was not smaller than that of traditional microwaves, and NADH staining also showed that the range of cell death was basically the same. The experimental results also showed that the alveolar tissue in the important core area was significantly compressed, and the ablation needle of the present invention is gentler than traditional ablation. Figure 5 This is a comparison of He-stained microscopic images of sections after ablation in living rabbit lungs using a conventional microwave ablation needle and the microwave ablation needle of the present invention. Figure 5 (a) is a microscopic image of He-stained sections after conventional microwave acupuncture ablation in living rabbit lungs. Figure 5 (b) A He-stained microscopic image of a rabbit lung section after microwave ablation using the present invention. As can be seen, conventional microwave ablation in living lung tissue shows significant compression and collapse of dozens of alveolar layers surrounding the needle tract, forming an eggshell-like structure, while distal lung tissue shows no significant thermal damage. However, microwave ablation using the present invention shows no significant shrinkage, compression, or collapse of the alveolar layers surrounding the needle tract, and alterations in alveolar structure are significantly mitigated.

[0034] The inventors conducted thermal property tests and simulations on isolated porcine lungs, demonstrating that the thermal properties and heat pattern of the microwave needles presented in this invention are fundamentally different from those of conventional microwaves, making them more suitable for ablating ground-glass nodules. The inventors also conducted in vivo pig trials, testing the same lung lobe with both the microwave ablation method presented in this invention and conventional microwave ablation. The results showed that while the ablation ranges were consistent, the postoperative scarring was significantly different, with steam microwave ablation producing smaller scars. Figure 6 Comparison of CT images of scars after ablation with a conventional microwave ablation needle and the microwave ablation needle of the present invention in live pig lungs. The top five images show CT images of scars after ablation with a conventional microwave ablation needle in live pig lungs, while the bottom five images show CT images of scars after ablation with the microwave ablation needle of the present invention in live pig lungs. The comparison reveals significant differences in scars, even at the same time. Scars after ablation with the microwave ablation needle of the present invention are smaller.

[0035] Figure 7Comparison of thermal images of a conventional microwave ablation needle and the patented microwave ablation needle in a live pig lung. A conventional microwave needle (on the right) and the patented microwave needle (on the left) demonstrate similar diameter differences in the ablation zone. However, with the conventional microwave needle, the lung tissue shrinks at the needle tip, forming an eggshell-like structure. This significantly increases reflection, resulting in a larger tail flame area. This reflected wave heats the coolant, leading to a higher needle shaft temperature.

[0036] In order to adapt to different clinical purposes, microwave ablation needles are designed into three different needle tip shapes. Figure 1 In the embodiment shown, the microwave ablation needle uses a conical needle tip, which is sharp and hard and can directly puncture the tumor. Figure 2 The microwave ablation needle shown uses a hemispherical needle head. This type of needle can push and deform the vessel wall when performing ablation near large blood vessels, thus establishing a safer microwave ablation area. Figure 3 The microwave ablation needle shown uses a rotating parabolic needle to avoid blood vessels and neural networks in tissues. The blunt tip of the needle can push blood vessels and neural tissues to both sides of the microwave needle without puncturing these tissues.

[0037] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A high-power microwave ablation needle for lung tumors, comprising a metal radiation head (1) and a feed coaxial cable, a cooling water pipe (8) and a metal needle rod (4) arranged in sequence from the inside out, wherein the inner conductor (6) of the feed coaxial cable is connected to the tail of the metal radiation head (1), and a first gap is formed between the outer conductor (7) of the feed coaxial cable and the tail of the metal radiation head (1) as a radiation window of the antenna, characterized in that: A dielectric tube (5) is provided between the metal needle rod (4) and the metal radiation head (1), and the microwave ablation needle further comprises a matching liquid delivery tube (3) sleeved outside the metal needle rod (4) and the dielectric tube (5), the outer diameter of the matching liquid delivery tube (3) being no greater than the outer diameter of the metal radiation head (1), a second gap being formed between the matching liquid delivery tube (3) and the metal needle rod (4) and the dielectric tube (5) as a matching liquid delivery channel, and a third gap (A) being formed between the front end of the matching liquid delivery tube (3) and the metal radiation head (1), the third gap (A) being an overflow annular groove suitable for overflow of the matching liquid.

2. The high-power microwave ablation needle for lung tumors according to claim 1, characterized in that: The front portion of the matching liquid delivery pipe (3) is provided with a plurality of small holes (2) distributed along the circumference, which are suitable for the matching liquid to overflow.

3. The high-power microwave ablation needle for lung tumors according to claim 1, characterized in that: The matching liquid delivery tube (3) is a PTFE tube, or a plastic tube with a PTFE anti-stick coating on the surface.

4. The high-power microwave ablation needle for lung tumors according to claim 1, characterized in that: A matching liquid inlet cavity (10) with a matching liquid inlet port (9) is provided at the rear of the metal needle rod (4), and the matching liquid delivery channel is connected to the matching liquid inlet cavity (10).

5. The high-power microwave ablation needle for lung tumors according to claim 1, characterized in that: The metal radiation head (1) serves as a radiation pole of the antenna, and the outer conductor (7) of the electrical coaxial cable serves as a reflection pole of the antenna.

6. The high-power microwave ablation needle for lung tumors according to claim 1, characterized in that: The front end of the cooling water diversion pipe (8) extends to the vicinity of the tail of the metal radiation head (1), the gap between the cooling water diversion pipe (8) and the outer conductor (7) of the feed coaxial cable forms a water inlet channel, and the gap between the cooling water diversion pipe (8) and the medium pipe (5) and the metal needle rod (4) forms a water return channel.

7. The high-power microwave ablation needle for lung tumors according to claim 1, characterized in that: The front portion of the metal radiation head (1) is in the shape of a cone, a hemisphere, or a rotational parabola.

8. The high-power microwave ablation needle for lung tumors according to claim 1, characterized in that: The tail of the metal radiation head (1) has a cylinder, the front of the dielectric tube (5) is sleeved and fixed on the cylinder, a protrusion is provided at the center of the tail of the cylinder, and the front end of the inner conductor (6) of the feeding coaxial cable is fixed to the protrusion by riveting or welding; the dielectric tube (5) is a ceramic tube.

9. The high-power microwave ablation needle for lung tumors according to claim 8, characterized in that: The front end of the cooling water inlet pipe (8) is partially fixed to the protrusion.

10. The high-power microwave ablation needle for lung tumors according to claim 6, characterized in that: A water inlet chamber (14) with a cooling water inlet (13) and a water outlet chamber (12) with a cooling water outlet (11) are provided at the rear of the metal needle rod (4); the water inlet channel is connected to the water inlet chamber (14), and the water return channel is connected to the water outlet chamber (12).

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