Flexible cryoablation catheter

Abstract

The utility model provides a flexible cryoablation catheter. The flexible cryoablation catheter comprises a needle; the far end of the flexible pipeline is connected with the needle head, the flexible pipeline sequentially wraps a vacuum forming layer, a first air return pipeline and a first air inlet pipeline from outside to inside in the radial direction, the first air inlet pipeline is used for introducing a freezing medium, a gap is formed between the far end of the first air inlet pipeline and the needle head, and the first air return pipeline is communicated with the first air inlet pipeline. A freezing medium is led out from the first air inlet pipeline through the gap and is recycled through the first air return pipeline; and the vacuum forming layer is connected with a vacuumizing device, so that when the vacuumizing device works, the vacuum forming layer forms vacuum. According to the flexible cryoablation catheter, the technical problem that a metal hard rod of a probe cannot be bent to enter along with a natural orifice and can only enter through puncture of a needle head is solved. And the conditions of injury, bleeding and the like caused by puncture of the skin are avoided.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of medical devices, and in particular to a flexible cryoablation catheter. Background Art

[0002] Tumor ablation technology is a precise, minimally invasive interventional treatment method that uses chemical or physical methods to act on single or multiple focal solid tumors under the guidance of modern imaging technology (such as ultrasound, CT, MRI, etc.) to directly eradicate or destroy tumor tissue and achieve the effect of "removing" the tumor.

[0003] Percutaneous cryoablation of tumors is considered to be a highly promising local ablation technology due to its advantages such as large ablation range, no pain, no need for general anesthesia, clear treatment boundaries, and real-time image monitoring. It has been rapidly promoted in clinical practice in recent years. Cryoablation refers to a method of freezing diseased tissue through low-temperature technology to achieve in situ inactivation of solid tissue. The working principle is to use low temperature to quickly cool down the diseased tissue to destroy cells, causing cell necrosis or apoptosis, thereby achieving the purpose of treatment. Since cryoablation uses the physical method of energy exchange to achieve the purpose of treatment, its trauma and side effects to the human body are far lower than conventional radiotherapy and chemotherapy, so it is hailed as a "green therapy".

[0004] Therefore, developing flexible cryoablation needles that can successfully reach the target tumor through the natural cavity and implement cryotherapy will significantly reduce tissue trauma and improve surgical efficiency, which is of great significance in the treatment of cavity tumors. Utility Model Content

[0005] In view of the above problems, the present application provides a flexible cryoablation catheter to overcome the above problems or at least partially solve the above problems.

[0006] An embodiment of the present application provides a flexible cryoablation catheter, which includes: a needle; a flexible pipeline, the distal end of which is connected to the needle, and the flexible pipeline radially covers a vacuum-forming layer, a first air return pipeline and a first air inlet pipeline in sequence from the outside to the inside, the first air inlet pipeline is used to introduce a freezing medium, and the first air return pipeline is used to recover the freezing medium, wherein the distal end of the first air inlet pipeline is connected to the first air return pipeline, and the freezing medium is introduced from the first air inlet pipeline and discharged to the first air return pipeline; the vacuum-forming layer is connected to a vacuum pumping device so that when the vacuum pumping device is working, the vacuum-forming layer forms a vacuum.

[0007] Optionally, a gap is formed between the distal end of the first air inlet pipeline and the needle, and the refrigerant medium is led out from the first air inlet pipeline through the gap and recovered through the first air return pipeline.

[0008] Optionally, the first air inlet pipeline is connected to the needle, and the first air inlet pipeline is provided with an exhaust hole; the refrigerant medium enters the first air return pipeline from the first air inlet pipeline through the exhaust hole.

[0009] Optionally, the flexible cryoablation catheter further comprises a vacuum switching structure connected to the needle, wherein the vacuum switching structure comprises: a vacuum forming chamber connected to the vacuum forming layer; and a return air switching chamber connected to the first return air pipeline.

[0010] Optionally, the flexible cryoablation catheter also includes a second air inlet pipeline connected to the first air inlet pipeline, the vacuum forming chamber and the return air switching chamber are respectively connected to the vacuum pipeline, the second air inlet pipeline and the second return air pipeline, and the second return air pipeline and the second air inlet pipeline are independently arranged in the vacuum pipeline.

[0011] Optionally, a base is provided at the proximal end of the vacuum transfer structure, which is respectively connected to the vacuum forming chamber and the return air transfer chamber, and the vacuum pipeline, the second return air pipeline and the second air intake pipeline are respectively connected to the vacuum forming chamber, the return air transfer chamber and the first air intake pipeline via the base.

[0012] Optionally, at least one of the vacuum pipeline and the second air return pipeline is respectively connected to the vacuum forming chamber and / or the air return transfer chamber through a transfer pipeline provided on the base.

[0013] Optionally, the transfer pipe includes a first pipe portion and a second pipe portion extending in the axial direction, and a third pipe portion extending in the radial direction, and the third pipe portion is communicated with the first pipe portion and the second pipe portion respectively.

[0014] Optionally, the flexible cryoablation catheter is further provided with a hollow handle, and the handle covers the vacuum transfer structure from the outside.

[0015] Optionally, the proximal ends of the vacuum pipeline, the second air return pipeline and the second air inlet pipeline are connected with quick connectors, the quick connectors are connected to the refrigerant medium output device and the refrigerant medium recovery device, and the vacuum pipeline is connected to the vacuum forming device.

[0016] Optionally, the flexible cryoablation catheter further comprises: a temperature measuring device, which is disposed in the first air return line and has a distal end in contact with the needle.

[0017] Optionally, the flexible cryoablation catheter also includes: a control unit, which is electrically connected to the vacuum forming device and starts the vacuum forming device when the control unit receives a start instruction; a detection unit, which is respectively connected to the control unit and the vacuum pipeline or the vacuum forming layer, and the detection unit is used to detect the vacuum degree in the vacuum pipeline or the vacuum forming layer. When it is detected that the vacuum degree reaches a set value, the detection unit sends a signal to the control unit, and the control unit controls the freezing medium to enter the first air inlet pipeline for cryoablation.

[0018] Optionally, after the cryoablation reaches a set time, the control unit controls the flexible cryoablation catheter to automatically perform ablation.

[0019] As can be seen from the above technical solutions, the flexible cryoablation catheter of the embodiment of the present application overcomes the technical problem that the metal hard rod of the probe cannot be bent to enter the natural cavity and can only be entered through needle puncture, thereby avoiding skin damage and bleeding caused by puncture.

[0020] In addition, the vacuum forming layer, the first air return line and the first air intake line are converted from the concentric structure of the lines to a parallel tubular structure, so that the air lines are separated and do not interfere with each other, and a high vacuum degree can be formed. The vacuum forming layer is expanded to a larger vacuum forming chamber through a vacuum transfer structure, so that vacuuming technology is realized inside the vacuum line and the vacuum forming chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0022] Figure 1 is a schematic diagram of an embodiment of a flexible cryoablation catheter of the present application;

[0023] Figure 2 is a schematic diagram of an embodiment of a vacuum switching structure of a flexible cryoablation catheter of the present application;

[0024] Figure 3A-3B is a schematic diagram of the distal end portion of two embodiments of a flexible cryoablation catheter of the present application;

[0025] Figure 4 It is a three-dimensional diagram of an embodiment of a pipeline adapter structure of the present application, with the base facing the distal end;

[0026] Figure 5 It is a three-dimensional diagram of an embodiment of a pipeline adapter structure of the present application, with the base facing the proximal end;

[0027] Figure 6A-6B They are cross-sectional views of a base of a pipeline adapter structure of the present application along different viewing angles.

[0028] Component number

[0029] 10: flexible cryoablation catheter; 101: needle; 102: flexible pipeline; 103: vacuum forming layer; 104: first return air pipeline; 105: first air inlet pipeline; 106: exhaust hole; 108: vacuum transfer structure; 109: vacuum forming chamber; 110: return air transfer chamber; 111: base; 112: transfer pipeline; 113: handle; 114: quick connector; 116: gap; 120: first tube part; 121: second tube part; 122: third tube part; 123: second air inlet pipeline; 124: vacuum pipeline; 125: second return air pipeline. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the embodiments of the present application should fall within the scope of protection of the embodiments of the present application.

[0031] The “distal end” mentioned above refers to the end of the flexible cryoablation catheter away from the operator during the surgical operation; the “proximal end” mentioned above refers to the end of the flexible cryoablation catheter close to the operator during the surgical operation.

[0032] The specific implementation of the embodiment of the present application is further explained below in conjunction with the accompanying drawings of the embodiment of the present application.

[0033] See also Figures 1 to 3A In a specific implementation of the present application, a flexible cryoablation catheter 10 is provided, which includes: a needle 101; a flexible pipeline 102, the distal end of which is connected to the needle 101, and the flexible pipeline 102 sequentially covers a vacuum-forming layer 103, a first return air pipeline 104, and a first air inlet pipeline 105 from outside to inside in radial direction, the first air inlet pipeline 105 is used to pass a freezing medium, and a gap 116 is formed between the distal end of the first air inlet pipeline 105 and the needle 101, and the freezing medium is led out from the first air inlet pipeline 105 through the gap 116, and is recovered to a recovery device through the first return air pipeline 104. The vacuum-forming layer 103 is connected to a vacuum-forming device, so that when the vacuum-forming device is working, the vacuum-forming layer 103 forms a vacuum.

[0034] See also Figure 3B In another embodiment, a flexible multimodal ablation catheter 10 is provided, which includes: a needle 101; a flexible pipeline 102, the distal end of which is connected to the needle 101, and the flexible pipeline 102 radially covers a vacuum forming layer 103, a first return air pipeline 104 and a first air inlet pipeline 105 in sequence from the outside to the inside, wherein the first air inlet pipeline 105 is connected to the needle 101, and the first air inlet pipeline 105 is provided with an exhaust hole 106; the freezing medium enters the first return air pipeline 104 from the first air inlet pipeline 105 via the exhaust hole 106; the vacuum forming layer 103 is connected to a vacuum forming device so that when the vacuum forming device is working, the vacuum forming layer 103 forms a vacuum. The main purpose of connecting the front end of the first air inlet pipeline 105 with the needle 101 is to connect the first air inlet pipeline 105 and the needle 101 as conductors for radio frequency energy transmission, which can reduce a wire inside the pipeline, save the internal space of the tube body and reduce the outer diameter of the tube body.

[0035] The flexible pipe 102 may be made of a flexible pipe with good lubricity and insulation. The material of the flexible pipe 102 may be a polymer material such as PTFE, Nylon, PEBAX, etc. The outer diameter of the flexible pipe may be between 1 mm and 4 mm, and the length of the flexible pipe 102 may be between 100 mm and 3000 mm. The material of the first air intake pipe 105 may be metal, such as stainless steel 304, 316L, brass, copper, etc. The material of the return pipe may be PTFE, Nylon, PEBAX, etc.

[0036] In one embodiment, the flexible cryoablation catheter 10 also includes a vacuum transfer structure 108 connected to the needle 101 , and the vacuum transfer structure 108 is provided with: a vacuum forming chamber 109 which is connected to the vacuum forming layer 103 ; and a return air transfer chamber 110 which is connected to the first return air pipeline 104 .

[0037] In one embodiment, the flexible cryoablation catheter 10 also includes a vacuum transfer structure 108 connected to the needle 101 , and the vacuum transfer structure 108 is provided with: a vacuum forming chamber 109 which is connected to the vacuum forming layer 103 ; and a return air transfer chamber 110 which is connected to the first return air pipeline 104 .

[0038] In one embodiment, the flexible cryoablation catheter 10 also includes a second air inlet pipeline 123 connected to the first air inlet pipeline 105, the vacuum forming chamber 109 and the return air switching chamber 110 are respectively connected to the vacuum pipeline 124, the second air inlet pipeline 123 and the second return air pipeline 125, and the second return air pipeline 125 and the second air inlet pipeline 123 are independently arranged in the vacuum pipeline 124.

[0039] In one embodiment, a base 111 is provided at the proximal end of the vacuum transfer structure 108, and the base 111 is respectively connected to the vacuum forming chamber 109 and the return air transfer chamber 110, and the vacuum pipeline 124, the second return air pipeline 125 and the second air inlet pipeline 123 are respectively connected to the vacuum forming chamber 109, the return air transfer chamber 110 and the first air inlet pipeline 105 via the base 111.

[0040] In one embodiment, at least one of the vacuum pipeline 124 and the second gas return pipeline 125 is communicated with the vacuum forming chamber 109 and / or the gas return transfer chamber 110 respectively through a transfer pipeline 112 provided on the base 111. The transfer pipeline 112 includes a first pipe portion 120 and a second pipe portion 121 extending in the axial direction, and a third pipe portion 122 extending in the radial direction, and the third pipe portion 122 is communicated with the first pipe portion 120 and the second pipe portion 121 respectively.

[0041] In one embodiment, the flexible cryoablation catheter 10 is further provided with a hollow handle 113 , and the handle 113 covers the vacuum transfer structure 108 from the outside.

[0042] In one embodiment, the vacuum pipeline 124, the second air return pipeline 125 and the proximal end of the second air inlet pipeline 123 are connected to a quick connector 114, the quick connector 114 is connected to a refrigerant medium output device and a refrigerant medium recovery device, and the vacuum pipeline 124 is connected to the vacuum forming device. The vacuum forming device can be a vacuum pump or a vacuum pump.

[0043] In one embodiment, the flexible cryoablation catheter 10 further includes: a temperature measuring device, which is inserted into the first air return line 104 and the distal end of which contacts the needle 101; and a radio frequency circuit 116, the distal end of which is connected to the needle 101 and the proximal end of which is electrically connected to the energy generating device. The temperature measuring device can be a thermocouple or other temperature measuring devices.

[0044] In one embodiment, the flexible cryoablation catheter 10 also includes: a control unit, which is electrically connected to the vacuum forming device and starts the vacuum forming device when the control unit receives a start instruction; a detection unit, which is respectively connected to the control unit and the vacuum pipeline 124 or the vacuum forming layer 103, and the detection unit is used to detect the vacuum degree in the vacuum pipeline 124 or the vacuum forming layer 103. When it is detected that the vacuum degree reaches a set value, the detection unit sends a signal to the control unit, and the control unit controls the freezing medium to enter the first air inlet pipeline 105 for cryoablation.

[0045] The flexible cryoablation needle of the embodiment of the present application is mainly different from the traditional cryoablation needle (percutaneous puncture type) in that the pipeline of the flexible cryoablation needle entering the human body is longer (about 1m), and the outer tube material is usually a flexible polymer material with a high degassing coefficient under vacuum conditions. Therefore, if a conventional probe is used to pre-make a vacuum tube, the high vacuum degree of the flexible probe needle tube will be difficult to maintain for a long time.

[0046] During the operation, the endoscope first passes through the natural cavity of the human body (oral cavity, anus, urethra, etc.), cooperates with the light source and imaging system of the endoscope to enter and find the lesion location, and then the flexible cryoablation catheter 10 enters through the instrument channel of the endoscope until the lesion tissue is located for surgical treatment, thereby solving the technical problem that the metal hard rod of the probe cannot bend and enter the natural cavity and can only be entered through puncture of the needle 101. It avoids skin damage and bleeding caused by puncture.

[0047] The working modes of existing probes are all single freezing or radio frequency modes, which are difficult to achieve the freezing requirements of precise control and rapid pre-cooling of cryoablation. Due to differences in patients and lesion organs, the location of the lesion will also be different. For example, if a more demanding lesion location is encountered, the difficulty of the operation will be increased, the time of the operation will be prolonged, and the success rate of the operation will be reduced. The endoscope can enter the demanding lesion location from the natural cavity of the human body through the bending angle of the front end. The flexible cryoablation catheter 10 uses the internal channel of the endoscope to enter and finally reach the lesion location through its own bending for surgical treatment. The probe can only perform destructive puncture on the tissue, and once the wall of the cavity is penetrated, the result is often fatal.

[0048] The vacuum forming layer 103, the vacuum forming chamber 109 and the vacuum pipeline 124 form a vacuum layer structure. The vacuum forming device can evacuate the vacuum layer structure in real time. When the vacuum degree of the vacuum layer structure reaches the required requirement, the flexible cryoablation catheter 10 starts the transmission work. During the entire working period of the flexible cryoablation catheter 10, the vacuum forming device always keeps working to ensure the maintenance of the vacuum degree of the vacuum layer structure. When the flexible cryoablation catheter 10 finishes working, the vacuum forming device also stops working.

[0049] When the flexible cryoablation catheter 10 is working during surgery, the freezing medium will reach the needle 101 through the first air inlet line 105 to perform cryoablation on the tumor tissue. If frosting occurs on other parts of the flexible cryoablation catheter 10 except the needle 101, the liquid nitrogen cooling will be lost, so that the temperature at the needle 101 cannot reach the cryotherapy temperature, and other frosted parts will damage the normal tissues in the human body cavity. Therefore, the vacuum layer is indispensable. The real-time vacuum pumping technology ensures the maintenance of the vacuum degree of the vacuum layer during the operation, improves the success rate of the operation, and the vacuum layer plays an insulating role when the ablation needle is working. At present, the vacuum layer of the probe is mostly pre-processed, rather than real-time suction. If the vacuum layer leaks or the vacuum degree decreases before use, it will cause damage to the patient and the instrument. The connection method between the vacuum line 124 and the vacuum forming device can be a VCR joint sealing connection, or it can be connected and sealed with a latex tube through a metal lead-out tube. The connection method is not limited as long as it can play a sealing role.

[0050] The base 111 can play the role of connection, sealing and transition. The first air inlet pipeline 105 can be connected to the base 111 by welding, the first air return pipeline 104 can be connected to the vacuum forming chamber 109 by welding, and the proximal end of the flexible pipeline 102 is connected to the handle 113 or the vacuum transfer structure 108 to play the role of fixing and sealing. The proximal end of the base 111 is provided with four channels, one of which is a temperature measurement channel. The far end of the thermocouple is connected to the needle 101, and the middle passes through the base 111 to reach the quick-connect joint 114 to realize the temperature measurement function; the other three are gas channels. The first air inlet pipeline 105 is connected to the second air inlet pipeline 123 through a welding joint, the return air transfer chamber 110 is connected to the second return air pipeline 125 through a welding joint, and the vacuum forming chamber 109 is connected to the vacuum pipeline 124 through a welding joint. As a result, the vacuum forming layer 103, the first return air pipeline 104 and the first air inlet pipeline 105 are converted from the concentric structure of the pipeline to a parallel tubular structure, so that each gas path is separated and does not interfere with each other, and a high vacuum degree can be formed. The vacuum forming layer 103 is expanded to the vacuum forming chamber 109 with a larger space through the vacuum transfer structure 108, so that the vacuum forming technology is realized inside the vacuum pipeline 124 and the vacuum forming chamber 109.

[0051] The air inlet on the base is still designed as a coaxial center hole straight-through structure without conversion, and the air return hole is designed to be parallel to the air inlet and still a straight-through structure. The position of the air return hole is still within the connection range of the air return adapter chamber and the base, so it does not affect the gas return performance; the vacuum hole is not a straight-through structure. After one end is designed side by side with the air inlet and the air return hole, the other end is converted into a side-by-side structure close to the air inlet and the air return hole through the internal conversion hole of the base, which is convenient for the connection of the respective pipelines after conversion. In this way, the vacuum path converts the coaxial structure into a side-by-side structure through the conversion of the base, and the air inlet and air return paths are separated and do not interfere with each other, so that the formation of a high vacuum degree can be achieved.

[0052] The flexible cryoablation catheter 10 has a cryoablation working mode, that is, through the rapid temperature change from local freezing to sub-high temperature, the tumor tissue is subjected to drastic changes in temperature and stress in a short period of time, effectively achieving in situ fragmentation of tumor cells and tumor microvessels, maximally releasing tumor antigens, immune-related factors, and a large number of danger signals, and mechanically destroying tumor cells through deep freezing to form ice crystals, which can release a large number of tumor antigens. However, tumor cells in the sub-low temperature zone at the edge of cryoablation are mainly apoptotic, which can cause immunosuppression. The thermocouple can reach the needle position through the vacuum formation layer or through the first return air line. There is no restriction on the arrival method, as long as the temperature measurement can be achieved.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A flexible cryoablation catheter, characterized in that: The flexible cryoablation catheter comprises: Needles; A flexible pipeline, the distal end of which is connected to the needle, the flexible pipeline radially covers the vacuum forming layer, the first air return pipeline and the first air inlet pipeline in sequence from the outside to the inside, the first air inlet pipeline is used to pass the freezing medium, and the first air return pipeline is used to recover the freezing medium, wherein, The far end of the first air inlet pipeline is connected to the first air return pipeline, and the refrigerant medium is introduced from the first air inlet pipeline and led out to the first air return pipeline; the vacuum forming layer is connected to the vacuum pumping device so that when the vacuum pumping device is working, the vacuum forming layer forms a vacuum.

2. The flexible cryoablation catheter according to claim 1, characterized in that: A gap is formed between the distal end of the first air inlet pipeline and the needle, and the freezing medium is led out from the first air inlet pipeline through the gap and recovered through the first air return pipeline.

3. The flexible cryoablation catheter according to claim 1, characterized in that: The first air inlet pipeline is connected to the needle, and the first air inlet pipeline is provided with an exhaust hole; the refrigerant enters the first air return pipeline from the first air inlet pipeline through the exhaust hole.

4. The flexible cryoablation catheter according to claim 1, characterized in that: The flexible cryoablation catheter also includes a vacuum switching structure connected to the needle, and the vacuum switching structure is provided with: a vacuum forming chamber in communication with the vacuum forming layer; A return air transfer chamber is communicated with the first return air pipeline.

5. The flexible cryoablation catheter according to claim 4, characterized in that: The flexible cryoablation catheter also includes a second air inlet pipeline connected to the first air inlet pipeline. The vacuum forming chamber and the return air switching chamber are respectively connected to the vacuum pipeline, the second air inlet pipeline and the second return air pipeline, and the second return air pipeline and the second air inlet pipeline are independently arranged in the vacuum pipeline.

6. The flexible cryoablation catheter according to claim 5, characterized in that: A base is provided at the proximal end of the vacuum transfer structure, and the base is respectively connected to the vacuum forming chamber and the return air transfer chamber, and the vacuum pipeline, the second return air pipeline and the second air intake pipeline are respectively connected to the vacuum forming chamber, the return air transfer chamber and the first air intake pipeline via the base.

7. The flexible cryoablation catheter according to claim 6, characterized in that: At least one of the vacuum pipeline and the second air return pipeline is communicated with the vacuum forming chamber and / or the air return transfer chamber respectively through a transfer pipe arranged on the base.

8. The flexible cryoablation catheter according to claim 7, characterized in that: The transfer pipe includes a first pipe portion and a second pipe portion extending in an axial direction, and a third pipe portion extending in a radial direction, wherein the third pipe portion is communicated with the first pipe portion and the second pipe portion respectively.

9. The flexible cryoablation catheter according to claim 2, characterized in that: The flexible cryoablation catheter is also provided with a hollow handle, and the handle covers the vacuum transfer structure from the outside.

10. The flexible cryoablation catheter according to claim 7, characterized in that: The flexible cryoablation catheter also includes: A control unit, the control unit is electrically connected to the vacuum forming device, and starts the vacuum forming device when the control unit receives a start instruction; A detection unit is respectively connected to the control unit and the vacuum pipeline or the vacuum forming layer. The detection unit is used to detect the vacuum degree in the vacuum pipeline or the vacuum forming layer. When it is detected that the vacuum degree reaches a set value, the detection unit sends a signal to the control unit, and the control unit controls the freezing medium to enter the first air inlet pipeline for cryoablation.

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