Ablation device

Abstract

The application provides an ablation device, and relates to the technical field of medical instruments.The ablation device comprises a dipole antenna used for radiating microwave energy to tissue to be treated; the dipole antenna comprises a radiation part, a feed-in wire, a radiation tube, a choke ring and a protective sleeve; the radiation part and the choke ring are two poles of the dipole antenna respectively; the distal end of the feed-in wire is electrically connected to the proximal end of the radiation part; the choke ring is sleeved outside the feed-in wire, and the choke ring and the radiation part are arranged axially at intervals; the radiation tube is sleeved outside the feed-in wire, and the radiation tube is located between the choke ring and the radiation part; the protective sleeve covers the rear part of the radiation part, the radiation tube and the front part of the choke ring; the feed-in wire, the radiation tube and the protective sleeve are all bendable.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to an ablation device. Background Technology

[0002] Microwave ablation technology is widely used in the treatment of liver tumors, thyroid nodules, and lung nodules due to its advantages such as minimal invasiveness, high efficiency, and rapid postoperative recovery. For lung nodules, it is divided into two methods: percutaneous puncture and endoscopic non-invasive treatment. The so-called endoscopic non-invasive treatment involves inserting an ablation catheter through the treatment channel of a bronchoscope to the lesion. Because the bronchoscope approaches the lesion entirely through the body's natural cavities (bronchus), the entire process is non-invasive, with extremely low postoperative complications, and represents the future direction of lung nodule treatment.

[0003] Because bronchoscopy is a non-invasive treatment, it involves delivering the ablation catheter to the lesion through the working channel of the bronchoscope. However, the bronchoscope is often highly tortuous within the patient's lungs, thus requiring extremely high flexibility and adaptability in the ablation catheter. Secondly, microwave ablation has been applied to the treatment of lung nodules later than to liver tumors. Currently, the microwave transmitter design of commercially available ablation catheters is largely based on the design of microwave ablation antennas for liver tumors. However, lung nodules and liver tumors have completely different tissue structures and bioelectrical properties, resulting in less than ideal treatment outcomes. For example, severe charring or insufficient ablation area can lead to residual tumor tissue post-operatively. Summary of the Invention

[0004] The purpose of this invention is to provide an ablation device to alleviate the technical problems of insufficient flexibility and insufficient ablation range of existing ablation devices.

[0005] The present invention provides an ablation device comprising: a dipole antenna, wherein the dipole antenna is used to radiate microwave energy to the tissue to be treated;

[0006] The dipole antenna includes a radiating part, a feed line, a radiating tube, a choke ring, and a protective sleeve, wherein the radiating part and the choke ring are the two poles of the dipole antenna, respectively.

[0007] The distal end of the feed line is electrically connected to the proximal end of the radiating part, the choke ring is sleeved on the outside of the feed line, and the choke ring and the radiating part are spaced apart along the axial direction;

[0008] The radiating tube is sleeved on the outside of the feed line, and the radiating tube is located between the choke ring and the radiating part;

[0009] The protective sleeve covers the rear part of the radiating section, the radiating tube, and the front part of the choke ring;

[0010] The feed line, radiating tube, and protective sleeve are all flexible.

[0011] Furthermore, the axial length L1 of the radiating part is λ / 4, where,

[0012]

[0013] ε γ is the relative permittivity of the tissue to be ablated, c is the speed of light, and f is the operating frequency of the ablation microwave.

[0014] And / or, the outer diameter r of the radiating part is ≤ (φ-0.2) mm, wherein, The working channel diameter of the tissue to be processed.

[0015] Furthermore, the choke ring is fitted on the outside of the feed line to suppress the reverse current on the feed line and optimize the microwave ablation morphology.

[0016] And / or, the axial length L3 of the choke ring is λ / 4.

[0017] Furthermore, a groove is provided in the axial middle part of the choke ring, and the proximal end of the protective sleeve covers the groove.

[0018] Furthermore, the axial length L2 of the radiating tube is λ / 4–3λ / 4.

[0019] Furthermore, the ablation device also includes a catheter body and a handle, with the distal end of the catheter body connected to the choke ring and the proximal end of the catheter body connected to the distal end of the handle;

[0020] The handle is equipped with a coolant circulation mechanism; a water supply pipe is provided inside the conduit body, and the feed line passes through the water supply pipe.

[0021] Furthermore, the coolant circulation mechanism includes an inlet chamber, an outlet chamber, an inlet pipe, and an outlet pipe, wherein the inlet chamber is connected to the inlet pipe, and the outlet chamber is connected to the outlet pipe;

[0022] The conduit body also includes a support tube, the water supply tube is located inside the support tube, and the two are radially spaced to form a first cavity; the water supply tube and the feed line are radially spaced to form a second cavity, and the first cavity and the second cavity are connected to the proximal end face of the choke ring.

[0023] The water inlet chamber is connected to the second chamber; the water outlet chamber is connected to the first chamber.

[0024] Furthermore, the proximal side of the choke ring is filled with a sealing medium.

[0025] Furthermore, the outer wall of the catheter body is provided with length markings arranged along its axial direction.

[0026] This invention has at least the following advantages or beneficial effects:

[0027] The ablation device provided by the present invention includes: a dipole antenna for radiating microwave energy to the tissue to be treated; the dipole antenna includes a radiating part, a feed line, a radiating tube, a choke ring, and a protective sleeve, wherein the radiating part and the choke ring are the two poles of the dipole antenna; the distal end of the feed line is electrically connected to the proximal end of the radiating part; the choke ring is sleeved on the outside of the feed line, and the choke ring and the radiating part are spaced apart along the axial direction; the radiating tube is sleeved on the outside of the feed line, and the radiating tube is located between the choke ring and the radiating part; the protective sleeve covers the rear part of the radiating part, the radiating tube, and the front part of the choke ring; the feed line, the radiating tube, and the protective sleeve are all bendable.

[0028] First, the middle section of the dipole antenna is flexible and can be bent freely, allowing it to pass through most endoscopic clamp channels and ultimately reach most lesions for ablation treatment, solving the problem of clinically visible but unreachable lesions. Based on dipole antenna theory, the radiating part and the choke ring are the two poles of the evolved dipole antenna. Since the radiating tubes between the radiating part and the choke ring can radiate microwave energy into the tissue, the ablation range is increased, completely solving the problem of insufficient ablation range caused by factors such as charring in conventional microwave ablation antennas. Attached Figure Description

[0029] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 A schematic diagram of the ablation device provided in an embodiment of the present invention;

[0031] Figure 2 A cross-sectional view (free bending state) of the dipole antenna of the ablation device provided in an embodiment of the present invention;

[0032] Figure 3 for Figure 2 A magnified view of a portion of position A in the middle;

[0033] Figure 4 for Figure 2 A magnified view of a portion of position B in the middle;

[0034] Figure 5 for Figure 2 A cross-sectional view along the C-C direction;

[0035] Figure 6 for Figure 2 A cross-sectional view along the D-D direction;

[0036] Figure 7 A cross-sectional view (straightened state) of the dipole antenna of the ablation device provided in an embodiment of the present invention;

[0037] Figure 8 An internal view of the handle of the ablation device provided in an embodiment of the present invention;

[0038] Figure 9 for Figure 8 A magnified view of the area at position E in the middle.

[0039] Icons: 1 - Radiation section; 2 - Protective sleeve; 3 - Radiation tube;

[0040] 4 – Feed line; 401 – Inner conductor; 402 – Dielectric layer; 403 – Outer conductor;

[0041] 5 – Choke ring; 501 – Groove; 61 – Water supply pipe; 62 – Water inlet chamber; 63 – Water outlet chamber; 64 – Water inlet pipe; 65 – Water outlet pipe; 66 – RF connector; 67 – First cavity; 68 – Second cavity;

[0042] 7 – Radiation medium; 8 – Sealing medium; 9 – Support tube;

[0043] 100 – Dipole antenna; 200 – Conduit body; 210 – Scale; 300 – Handle. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0045] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0046] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0047] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0048] Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0049] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0050] like Figure 1 As shown, the ablation device includes a dipole antenna 100, a catheter body 200, and a handle 300. The dipole antenna 100 is the part that radiates microwave energy to the tissue to be treated. The catheter body 200 connects the dipole antenna 100 and the handle 300, which is the part of the ablation device that is held.

[0051] like Figure 7 As shown, the dipole antenna 100 has a multi-segment structure, including a radiating section 1 (first segment), a feed line 4, a radiating tube 3 (second segment), a choke ring 5 (third segment), and a protective sleeve 2. According to the theory of the dipole antenna 100, the radiating section 1 is one of the poles of the dipole antenna 100, and the axial length L1 of the radiating section 1 is related to the wavelength λ of microwaves in tissues (e.g., lung tissue).

[0052] Microwaves propagate in different human tissues, and the wavelength λ is calculated using the following formula:

[0053]

[0054] in, It is the wavelength in free space, εγ It is the relative permittivity of the structure, and c is the speed of light (3 x 10⁻⁶). 8 (m / s), where f is the frequency.

[0055] According to the above formula, the microwave frequency (ε) at 2.45 GHz can be obtained. γ (This can be obtained experimentally) The wavelength λ in different human tissues:

[0056] Table 2

[0057] Wavelengths (cm) of 2.45G microwaves in different human tissues

[0058] Human organs liver Lungs (not inflated) Lungs (inflated) thyroid wavelength λ 1.86 2.12 2.69 1.9－2.1

[0059] According to relevant literature, the wavelength of 2.45 GHz microwaves in lung tissue (inflatable) is approximately 2.69 cm. Based on λ / 4, the axial length L1 of the radiating part 1 is calculated to be 6.7 mm.

[0060] The outer diameter of the radiating part 1 is related to the working channel diameter φ of the endoscope, and the outer diameter of the radiating part 1 is ≤ φ - 0.2 mm. In this embodiment, a bronchus tube with a working channel of 2 mm, which is commonly used in the market, is selected, and the outer diameter of the radiating part 1 can be set to 1.6 mm.

[0061] like Figure 2 - Figure 4 As shown, the feed line 4 includes an inner conductor 401, a dielectric layer 402, and an outer conductor 403 arranged sequentially from the inside out. In this embodiment, a flexible radio frequency transmission line is selected. The inner conductor 401 and the dielectric layer 402 extend into the interior of the radiating part 1. The end face of the radiating part 1 has a stepped structure. The inner conductor 401 extends 4 mm into the radiating part 1, and a reliable electrical connection is achieved between the inner conductor 401 and the radiating part 1 through processes such as welding and crimping. The dielectric layer 402 extends into the radiating part 1. The space between the dielectric layer 402 and the radiating part 1 is filled with a radiation dielectric 7. In practice, this filling dielectric can be a high-temperature resistant adhesive (with a dielectric constant of 2-3 at 2.45 GHz) or other medical materials.

[0062] like Figure 7 As shown, a radiating tube 3 is fitted around the outer conductor 403. Based on data calculations and multiple verifications, experiments have shown that when the axial length L2 of the radiating tube 3 is λ / 4–3λ / 4, this structural dimension can achieve a relatively ideal ablation range while maintaining a small charring zone. Since lung tissue is selected as the ablation tissue in this embodiment, the axial length of the radiating tube 3 can be designed to be 12 mm. Regarding material selection, polytetrafluoroethylene (PTFE) can be used, as this material has outstanding characteristics in terms of temperature resistance and dielectric constant.

[0063] like Figure 5 and Figure 6As shown, the choke ring 5 is fitted onto the outer conductor 403. Its main function is to suppress the reverse current on the outer conductor 403 and alleviate the reverse heating problem of the dipole antenna 100. Its axial length L3 is also 1 / 4 of the wavelength λ of microwaves in lung tissue. In this embodiment, it is set to 6.5 mm.

[0064] The choke ring 5 has a groove 501 in the middle of its axial direction. The proximal end of the protective sleeve 2 is covered in the groove 501 of the choke ring 5 to prevent the protective sleeve 2 from sliding axially.

[0065] The protective sleeve 2 covers the rear part of the radiating part 1, the radiating tube 3, and the choke ring 5 (heat shrinking process can be used in actual production). Its main function is to protect the dipole antenna 100 and prevent the dipole antenna 100 from being damaged under extreme operation.

[0066] like Figure 8 and Figure 9 As shown, the catheter body 200 supports the dipole antenna 100 and the handle 300. According to this embodiment, the selected bronchoscope working channel (2mm) has an outer diameter of 1.6mm. It is a nested structure. The innermost part is a portion of the feed line 4, the middle part is the water supply pipe 61, and the outermost part is the support pipe 9. The wall thickness of the water supply pipe 61 is ≤0.05mm, and its inner and outer diameters must conform to the following formula:

[0067]

[0068] in, These are the inner and outer diameters of the water supply pipe 61, respectively. The inner diameter of support tube 9-1 The outer diameter of feed line 4 。

[0069] like Figure 7 As shown, the protective sleeve 2 and the support tube 9 can be a two-section structure or an integral structure. To ensure the microwave radiation efficiency of the dipole antenna 100, the wall thickness of the protective sleeve 2 should be ≤0.05mm; at the same time, to ensure the structural characteristics of the support tube 9, the wall thickness should be between 0.05mm and 0.15mm. Therefore, if it is an integral design, it needs to be a double-wall thickness structure with a thinner wall at the far end (≤0.05mm) and a thicker wall at the near end (0.05mm-0.15mm). Specifically, in this embodiment, the protective sleeve 2 and the support tube 9 are selected as an integral design (thin at the front and thick at the rear). The inner wall of the protective sleeve 2 is tightly fitted with the outer wall of the radiating tube 3. The wall thickness of the protective sleeve 2 is selected as 0.03mm in this embodiment; the support tube 9 is selected as 0.1mm.

[0070] The proximal end of the choke ring 5 is filled with a sealing medium 8, which can be a high-temperature medical adhesive.

[0071] The catheter body 200 is provided with a length scale 210. The first starting scale 210 position can be the length L4 = l + 30 mm to the distal end of the catheter body 200, where l is the length of the endoscope working channel. According to the commonly used bronchoscope working channel length on the market, this embodiment is set to: L4 = 730 mm.

[0072] The handle 300 is the gripping component of the ablation catheter, and its internal design includes a coolant circulation mechanism and an RF connector 66.

[0073] The coolant circulation mechanism features a dual-chamber design, with the front and rear chambers being the inlet chamber 62 and the outlet chamber 63, respectively. The inlet chamber 62 is connected to the inlet pipe 64, and the outlet chamber 63 is connected to the outlet pipe 65. The water circulation path is as follows: coolant enters the inlet chamber 62 through the inlet pipe 64, then enters the second chamber 68 between the feed line 4 and the supply pipe 61, and finally flows back into the first chamber 67 between the supply pipe 61 and the support pipe 9 at the end face of the choke ring 5. Finally, it flows back to the outlet chamber 63 and exits through the outlet pipe 65, achieving the cooling effect.

[0074] The RF connector 66 is fixed to the handle 300 and connected to the feed line 4.

[0075] In summary, the ablation device in this embodiment has two main innovative features:

[0076] (1) Based on the theory of dipole antenna 100, a flexible structure was designed, in which the dipole antenna 100 can also be bent freely. The radiating part 1 and the choke ring 5 of the dipole antenna 100 are the two poles after the evolution of the dipole antenna 100, and their structural dimensions are consistent with the wavelength of microwaves in the treated tissue. Since the part between the radiating part 1 and the choke ring 5 (radiating tube 3) can radiate microwave energy into the tissue, the ablation range can reach more than 3cm, which completely solves the problem of insufficient ablation range caused by factors such as charring of conventional microwave ablation antennas;

[0077] (2) The dipole antenna 100 is a multi-segment structure design (currently all are single-end structures), namely the radiating part 1 (first segment), the choke ring 5 (third segment) and the radiating tube 3 (second segment) between the two. The radiating tube 3 is a flexible structure. The multi-segment structure + flexible structure of the radiating tube 3 can ensure that the dipole antenna 100 of the ablation catheter can pass through most of the endoscope channels and finally reach most of the lesions to perform ablation treatment, solving the problem of clinically visible but not reached lesions.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An ablation device, characterized in that, include: A dipole antenna (100) for radiating microwave energy to the tissue to be treated; The dipole antenna (100) includes a radiating part (1), a feed line (4), a radiating tube (3), a choke ring (5), and a protective sleeve (2). The radiating part (1) and the choke ring (5) are the two poles of the dipole antenna (100), respectively. The far end of the feed line (4) is electrically connected to the near end of the radiating part (1), the choke ring (5) is sleeved on the outside of the feed line (4), and the choke ring (5) and the radiating part (1) are spaced apart along the axial direction. The radiating tube (3) is sleeved on the outside of the feed line (4), and the radiating tube (3) is located between the choke ring (5) and the radiating part (1); The protective sleeve (2) covers the rear of the radiating part (1), the radiating tube (3), and the front of the choke ring (5); The feed line (4), the radiating tube (3), and the protective sleeve (2) are all bendable; The feed line (4) includes an inner conductor (401), a dielectric layer (402), and an outer conductor (403) arranged sequentially from the inside to the outside. The feed line (4) is a flexible radio frequency transmission line. Its inner conductor (401) and dielectric layer (402) extend into the interior of the radiating part (1). The end face of the radiating part (1) has a stepped structure. The inner conductor (401) and the radiating part (1) are reliably electrically connected through welding or crimping processes. The dielectric layer (402) extends into the radiating part (1). The radiating part (1) and the choke ring (5) of the dipole antenna (100) are the two poles after the evolution of the dipole antenna (100). The radiation tube (3) between the radiating part (1) and the choke ring (5) can radiate microwave energy into the tissue.

2. The ablation device according to claim 1, characterized in that, The axial length L1 of the radiating part (1) is λ / 4, where, ， is the relative permittivity of the tissue to be ablated, c is the speed of light, and f is the operating frequency of the ablation microwave. And / or, the outer diameter r of the radiating part (1) is ≤ (φ-0.2) mm, where φ is the working forceps aperture of the tissue to be treated.

3. The ablation device according to claim 2, characterized in that, The choke ring (5) is fitted on the outside of the feed line (4) to suppress the reverse current on the feed line (4); And / or, the axial length L3 of the choke ring (5) is λ / 4.

4. The ablation device according to claim 1, characterized in that, The choke ring (5) has a groove (501) in the middle of its axial direction, and the proximal end of the protective sleeve (2) is covered by the groove (501).

5. The ablation device according to claim 1, characterized in that, The axial length L2 of the radiation tube (3) is λ / 4-3λ / 4.

6. The ablation device according to claim 2, characterized in that, The ablation device further includes a catheter body (200) and a handle (300), the distal end of the catheter body (200) being connected to the choke ring (5), and the proximal end of the catheter body (200) being connected to the distal end of the handle (300); A coolant circulation mechanism is provided on the handle (300); a water supply pipe (61) is provided inside the conduit body (200), and the feed line (4) passes through the water supply pipe (61).

7. The ablation device according to claim 6, characterized in that, The coolant circulation mechanism includes an inlet chamber (62), an outlet chamber (63), an inlet pipe (64), and an outlet pipe (65). The inlet chamber (62) is connected to the inlet pipe (64), and the outlet chamber (63) is connected to the outlet pipe (65). The conduit body (200) also includes a support tube (9), the water supply tube (61) is located inside the support tube (9), and the two are radially spaced to form a first cavity (67); the water supply tube (61) and the feed line (4) are radially spaced to form a second cavity (68), and the first cavity (67) and the second cavity (68) are connected to the proximal end face of the choke ring (5); The water inlet chamber (62) is connected to the second chamber (68); the water outlet chamber (63) is connected to the first chamber (67).

8. The ablation device according to claim 6, characterized in that, The choke ring (5) is filled with a sealing medium (8) on one side near its proximal end.

9. The ablation device according to claim 6, characterized in that, The outer wall of the catheter body (200) is provided with length markings (210) arranged along its axial direction.

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