Water-cooling-free and carbonization-free microwave ablation needle based on double-layer vacuum structure

Abstract

The utility model provides a water-cooling-free carbonization-free microwave ablation needle based on a double-layer vacuum structure, and belongs to the field of microwave ablation, the water-cooling-free carbonization-free microwave ablation needle comprises a radio frequency connector, a medical double-layer stainless steel vacuum needle rod, a coaxial cable, an insulating medium sleeve and a needle head, the coaxial cable penetrates through the medical double-layer stainless steel vacuum needle rod, one end of the coaxial cable is connected with the radio frequency connector, and the other end of the coaxial cable is connected with the needle head; the insulating medium sleeve wraps the connection position of the coaxial cable and the needle head. According to the microwave ablation needle, circulating water cooling is not needed, the weight of the ablation needle can be reduced, heat energy does not need to be taken away due to water cooling circulation, and therefore the microwave ablation needle is suitable for ablation with small power (20 W or below), and carbonization is avoided under the condition that the size of an ablation area is considered.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of microwave ablation, in particular to a water-free and carbon-free microwave ablation needle based on a double-layer vacuum structure. BACKGROUND

[0002] During the microwave ablation process, direct energy deposition in a limited action range can cause the central temperature of the tissue around the microwave antenna to be too high. Carbonization in the ablation lesion is prone to occur, and highly dry carbonized tissue usually appears. The tissue after microwave ablation can be divided into a carbonized area (black part), a coagulation area (light yellow), a transition area (red hyperemic zone) and a normal area.

[0003] The carbonized area can adhere to the ablation needle, making it difficult to pull out the needle, and even bleeding along the needle path. The carbonized area hinders the heat propagation of the antenna, affects the diffusion of heat and limits the ablation treatment range.

[0004] The current microwave ablation needle cannot realize carbon-free, and a new type of low-power microwave ablation needle should be designed to reduce tissue carbonization. In clinical practice, the power of the microwave ablation needle is usually large (50W / 60W / 70W, etc.). This is because the current microwave ablation needle has a circulating water cooling system to reduce the temperature of the ablation needle shaft, and at the same time, most of the heat energy is also taken away, so it is necessary to use a larger power for microwave ablation. However, using a larger power for microwave ablation can form a high temperature (carbonization threshold temperature is 130℃) of 160℃ or above within a few seconds after ablation, resulting in a larger carbonization. There is currently no water-free and carbon-free microwave ablation needle. CONTENT OF THE INVENTION

[0005] The application provides a water-free and carbon-free microwave ablation needle based on a double-layer vacuum structure, which does not need circulating water cooling, can reduce the weight of the ablation needle, does not need to take away heat energy due to water cooling circulation, is suitable for selecting a smaller power for ablation, and can realize carbon-free while considering the size of the ablation area.

[0006] The application provides a water-free and carbon-free microwave ablation needle based on a double-layer vacuum structure, which does not need circulating water cooling, can reduce the weight of the ablation needle, does not need to take away heat energy due to water cooling circulation, is suitable for selecting a smaller power for ablation, and can realize carbon-free while considering the size of the ablation area.

[0007] The radio frequency connector;

[0008] The medical double-layer stainless steel vacuum needle shaft;

[0009] The coaxial cable passes through the medical double-layer stainless steel vacuum needle shaft, one end is connected with the radio frequency connector, and the other end is connected with the needle head;

[0010] The insulating medium sleeve is wrapped around the coaxial cable and the position where the needle head is connected.

[0011] In the application, the medical double-layer stainless steel vacuum needle rod is a double-layer hollow pipe, comprising a vacuum pipe outer layer and a vacuum pipe inner layer pipe, and the interlayer of the vacuum pipe outer layer and the vacuum pipe inner layer pipe is a vacuum, wherein the outer diameter of the vacuum pipe outer layer is 2mm, the inner diameter of the vacuum pipe outer layer is 1.8mm, the outer diameter of the vacuum pipe inner layer pipe is 1.6mm, and the inner diameter of the vacuum pipe inner layer pipe is 1.4mm.

[0012] In the application, the outer diameter of the coaxial cable is 1.19mm, comprising an outer conductor, an insulator and an inner conductor, with diameters of 1.19mm, 0.94mm and 0.29mm respectively, the outer conductor material is seamless red copper pipe, the insulator material is polytetrafluoroethylene, and the inner conductor material is silver-plated copper-clad steel wire.

[0013] In the application, the maximum power of the microwave ablation needle is 20W, and the maximum ablation duration is 180s.

[0014] In the application, the coaxial cable is a semi-steel coaxial cable, with a capacitance of 95.1PF / M and an impedance of 50Ω.

[0015] In an embodiment of the application, the insulating medium sleeve is a hollow two-section cylindrical structure, with outer diameters of 2.0mm and 1.35mm and an inner diameter of 1.2mm.

[0016] In the application, the needle head is a brass conical shape, with a length of 11mm, a conical length of 5mm at the front end, and a cylindrical length of 6mm at the rear end.

[0017] The water-cooling-free and carbonization-free microwave ablation needle based on the double-layer vacuum structure of the application has the following beneficial effects:

[0018] 1. Without the built-in circulating water cooling structure of the traditional ablation needle, the weight of the ablation needle is reduced, and the manufacturing cost and the process difficulty of the ablation needle are also reduced.

[0019] 2. Without the water cooling circulation to take away heat energy, a smaller power (below 20W) is suitable for ablation to realize effective carbonization under the condition of considering the size of the ablation area, and the maximum temperature of the tissue in the ablation process can be controlled below 130℃ (carbonization threshold temperature).

[0020] Additional aspects and advantages of the application will be in part apparent and in part pointed out hereinafter in the description of the application. BRIEF DESCRIPTION OF DRAWINGS

[0021] The above and / or additional aspects and advantages of the application will become apparent and be readily understood from the following description, taken in connection with the accompanying drawings, in which:

[0022] Figure 1 is a structural diagram of a water-cooling-free and carbonization-free microwave ablation needle based on a double-layer vacuum structure provided by an embodiment of the present application;

[0023] Figure 2 is a physical diagram of a water-cooling-free and carbonization-free microwave ablation needle based on a double-layer vacuum structure provided by an embodiment of the present application;

[0024] Figure 3 is a simulation ablation geometric model diagram of a water-cooling-free and carbonization-free microwave ablation needle based on a double-layer vacuum structure provided by an embodiment of the present application;

[0025] Figure 4 is a simulation effect diagram of a water-cooling-free and carbonization-free microwave ablation needle based on a double-layer vacuum structure provided by an embodiment of the present application;

[0026] Figure 5 is a simulation effect diagram of a water-cooling-free and carbonization-free microwave ablation needle based on a double-layer vacuum structure provided by an embodiment of the present application. DETAILED DESCRIPTION

[0027] The embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0028] Figure 1 is a structural diagram of a water-cooling-free and carbonization-free microwave ablation needle based on a double-layer vacuum structure provided by an embodiment of the present application.

[0029] As shown in Figure 1 , the water-cooling-free and carbonization-free microwave ablation needle based on a double-layer vacuum structure comprises:

[0030] a radio frequency connector 1; the radio frequency connector of the embodiment of the present application is a standard SMA radio frequency connector;

[0031] a medical double-layer stainless steel vacuum needle rod; the medical double-layer stainless steel vacuum needle rod is a double-layer hollow tube, comprising a vacuum tube outer layer 2 and a vacuum tube inner layer tube 4, and the interlayer of the vacuum tube outer layer and the vacuum tube inner layer tube is a vacuum 3, wherein the outer diameter of the vacuum tube outer layer 2 is 2 mm, the inner diameter of the vacuum tube outer layer 2 is 1.8 mm, the outer diameter of the vacuum tube inner layer tube 4 is 1.6 mm, and the inner diameter of the vacuum tube inner layer tube 4 is 1.4 mm; the inside of the medical double-layer stainless steel vacuum needle rod is air 5;

[0032] a coaxial cable 6, which passes through the medical double-layer stainless steel vacuum needle rod, is connected with the radio frequency connector 1 at one end and is connected with a needle head 8 at the other end;

[0033] An insulating medium sleeve 7 is wrapped around the coaxial cable 6 and the needle 8 connection position.

[0034] In an embodiment of the present application, the outer diameter of the coaxial cable is 1.19 mm, including an outer conductor, an insulator and an inner conductor, with diameters of 1.19 mm, 0.94 mm and 0.29 mm respectively. The outer conductor is made of seamless red copper pipe, the insulator is made of polytetrafluoroethylene (PTFE), and the inner conductor is made of silver-plated copper-clad steel wire. The coaxial cable is a semi-steel coaxial cable, with a capacitance of 95.1 PF / M and an impedance of 50 Ω.

[0035] In an embodiment of the present application, the insulating medium sleeve is a hollow two-section cylindrical structure, with outer diameters of 2.0 mm and 1.35 mm respectively and an inner diameter of 1.2 mm. The material is polytetrafluoroethylene.

[0036] In an embodiment of the present application, the needle is made of brass and is conical, with a length of 11 mm, a conical front end with a length of 5 mm, and a cylindrical rear end with a length of 6 mm.

[0037] The maximum power of the water-cooling-free and carbonization-free microwave ablation needle based on the double-layer vacuum structure according to the embodiments of the present application is 20 W, and the maximum ablation duration is 180 s. The microwave ablation needle does not need the built-in water-cooling circulation structure of the traditional microwave ablation needle, which not only reduces the weight of the ablation needle, but also does not need to take away heat energy due to water-cooling circulation, and is suitable for selecting a smaller power (below 20 W) for ablation.

[0038] As Figure 2 The physical diagram of the water-cooling-free and carbonization-free microwave ablation needle based on the double-layer vacuum structure is shown, 1 is a radio frequency connector, 2 is a vacuum tube outer layer (ablation needle body), 6 is a coaxial cable, 7 is an insulating medium sleeve, and 8 is a needle.

[0039] 20 W and 10 W are selected as the ablation power, and different times are set for ablation.

[0040] As Figure 3A simulation ablation geometry model of the double-layer vacuum structure-based microwave ablation needle without water cooling and carbonization is shown. The COMSOL Multiphysics software is used to simulate the ablation heat field of the ablation needle. The ablation needle is mainly composed of a coaxial cable (inner conductor, insulating medium and outer conductor), a stainless steel tube and a puncture needle (transmitting front electrode), and a polytetrafluoroethylene insulating medium sleeve. The pig liver tissue is set to be isotropic and uniform, and the shape is cylindrical. The ablation needle geometry model and the liver tissue geometry model are set to be two-dimensional axisymmetric structures to save calculation time. The front part of the needle tip is set to be 40 mm away from the boundary, and the length of the liver tissue is set to be 120 mm and the width is set to be 60 mm to ensure the integrity of the ablation area. After the geometry model is established, the grid is divided in COMSOL. The grid near the energy radiation point of the ablation needle is set to be denser, and the grid far from the energy radiation point is set to be sparser. The maximum grid unit size is 4.44 mm, and the minimum grid unit size is 0.015 mm.

[0041] As Figure 4 A simulation ablation effect diagram of the double-layer vacuum structure-based microwave ablation needle without water cooling and carbonization is shown. The simulation ablation power is 20 W, and the time is 180 s. The area outlined by 59°C (cell inactivation threshold temperature) and 130°C (carbonization threshold temperature) is the coagulation area and the carbonization area. The long diameter and the short diameter of the measured coagulation area in the simulation result are 33 mm and 16 mm respectively. Since the maximum temperature of the tissue during the simulation is 129.5°C, the carbonization area is not outlined in the simulation result.

[0042] As Figure 5 A simulation ablation effect diagram of the double-layer vacuum structure-based microwave ablation needle without water cooling and carbonization is shown. The simulation ablation power is 20 W, and the time is 180 s. The long diameter of the measured coagulation area is 34 mm, and the short diameter is 18 mm. In addition, there is no carbonized component (black) in the coagulation area after ablation. Compared with the simulation result, the absolute error of the long diameter of the coagulation area in the simulation result and the actual coagulation area is 1 mm, and the absolute error of the short diameter is 2 mm.

[0043] The double-layer vacuum structure-based microwave ablation needle without water cooling and carbonization provided by the embodiment of the application can form an ellipsoidal non-carbonized coagulation area with a long diameter of 34 mm and a short diameter of 18 mm under an ablation dose of 20 W-180 s.

[0044] The water-free and carbon-free microwave ablation needle based on the double-layer vacuum structure according to the embodiment of the application comprises a radio frequency connector, a medical double-layer stainless steel vacuum needle rod, a coaxial cable, an insulating medium sleeve and a needle head, the coaxial cable passes through the medical double-layer stainless steel vacuum needle rod, one end of the coaxial cable is connected with the radio frequency connector, and the other end of the coaxial cable is connected with the needle head; and the insulating medium sleeve is wrapped around the position where the coaxial cable and the needle head are connected. The microwave ablation needle does not need to be cooled by circulating water, and both the weight of the ablation needle and the heat energy taken away by the water cooling circulation can be reduced, so that a smaller power (20W or less) is selected for ablation, so as to ensure carbon-free while considering the size of the ablation area.

[0045] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example" or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or N embodiments or examples in a suitable manner. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0046] In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "N" is at least two, for example, two, three, etc., unless otherwise specifically limited.

Claims

1. A waterless, carbonization-free microwave ablation needle based on a double-layer vacuum structure, characterized in that, include: RF connector; Medical double-layer stainless steel vacuum needle bar; A coaxial cable passes through the medical double-layer stainless steel vacuum needle bar, with one end connected to the radio frequency connector and the other end connected to the needle tip; An insulating dielectric sleeve is provided, which covers the connection between the coaxial cable and the needle tip.

2. The waterless, carbonization-free microwave ablation needle based on a double-layer vacuum structure according to claim 1, characterized in that, The medical double-layer stainless steel vacuum needle rod is a double-layer hollow tube, including an outer vacuum tube and an inner vacuum tube. The space between the outer and inner vacuum tubes is a vacuum. The outer diameter of the outer vacuum tube is 2 mm, the inner diameter is 1.8 mm, the outer diameter of the inner vacuum tube is 1.6 mm, and the inner diameter is 1.4 mm.

3. The waterless, carbonization-free microwave ablation needle based on a double-layer vacuum structure according to claim 1, characterized in that, The coaxial cable has an outer diameter of 1.19 mm and includes an outer conductor, an insulator, and an inner conductor with diameters of 1.19 mm, 0.94 mm, and 0.29 mm, respectively. The outer conductor is made of seamless copper tubing, the insulator is made of polytetrafluoroethylene, and the inner conductor is made of silver-plated copper-clad steel wire.

4. The waterless, carbonization-free microwave ablation needle based on a double-layer vacuum structure according to claim 1, characterized in that, The microwave ablation needle has a maximum power of 20W and a maximum ablation duration of 180s.

5. The waterless, carbonization-free microwave ablation needle based on a double-layer vacuum structure according to claim 1 or 3, characterized in that, The coaxial cable is a semi-steel coaxial cable with a capacitance of 95.1 pF / m and an impedance of 50 Ω.

6. The waterless, carbonization-free microwave ablation needle based on a double-layer vacuum structure according to claim 1, characterized in that, The insulating dielectric sleeve is a hollow two-section cylindrical structure with outer diameters of 2.0 mm and 1.35 mm and an inner diameter of 1.2 mm.

7. The waterless, carbonization-free microwave ablation needle based on a double-layer vacuum structure according to claim 1, characterized in that, The needle is a brass cone shape, 11mm long, with a 5mm long tapered front end and a 6mm long cylindrical rear end.

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