WO2018130095A1

WO2018130095A1 - Cryoablation therapy system

Info

Publication number: WO2018130095A1
Application number: PCT/CN2017/119958
Authority: WO
Inventors: 杨泰克•布; 刁月鹏; 葛均波; 沈雳
Original assignee: 康沣生物科技(上海)有限公司
Priority date: 2017-01-16
Filing date: 2017-12-29
Publication date: 2018-07-19
Also published as: CN106821489A; CN106821489B

Abstract

Provided is a cryoablation therapy system (10), comprising: a Dewar flask component, a pressure vessel component, a heat exchange component, and a freezing unit (600); the Dewar flask component receives a liquid refrigerant from the exterior; the pressure vessel component is arranged inside the Dewar flask component and receives the liquid refrigerant from the Dewar flask; in the pressure vessel (134), the liquid refrigerant is transformed, by means of the principles of liquid-gas conversion and expansion, to a working fluid having a higher pressure and temperature and delivered to a working-fluid pipeline; the heat exchange component is arranged inside the Dewar flask component; by means of a connection between the working-fluid pipeline and the pressure vessel component, the heat exchange component receives a working fluid from the pressure vessel component and transforms said working fluid into a working refrigerant and delivers the working refrigerant to a working-refrigerant pipeline; the freezing unit (600) is connected to the heat exchange component and used for receiving the working refrigerant, and its far end is the cold-source release region of the working refrigerant.

Description

Cryoablation treatment system

Related application

The present application claims priority to the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the disclosure.

Technical field

The present application relates to a medical device, and more particularly to a cryoablation therapy system for freezing and destroying biological tissue.

Background technique

Cryosurgical treatment is the proper freezing of the target biological tissue to be treated using extremely low temperatures and complex systems designed. Many of these systems use a working fluid that is connected to the system from an external high pressure gas tank through a long flexible transfer tube. These gas cylinders typically have a large internal volume to hold enough working fluid to ensure a typical cryosurgery procedure. Gas cylinders are usually made of steel with a very thick wall, which can meet the high pressure requirements, but at the same time make the gas tank very bulky. Due to the large size and high pressure, the pressurized gas cylinder is generally placed outside the freezing ablation unit, so the installation and operation of the system is complicated. The purpose of the present application is to develop an cryoablation unit with a single Dewar that removes the external gas cylinder, which receives the fluid refrigerant from the low pressure storage tank and automatically converts it into the desired ablation fluid, The ablative fluid is delivered to an ablation assembly of the catheter. The catheter receives the ablation fluid and returns the used fluid to the cryoablation unit.

Summary of the invention

It is an object of the present invention to provide an improved cryoablation therapy system for freezing and destroying biological tissue.

To achieve the above object of the present application, the technical solution adopted in the present application is:

A cryoablation therapy system comprising:

a Dewar component that receives liquid refrigerant from the outside;

a pressure vessel component disposed inside the Dewar component to receive liquid refrigerant from the Dewar component, wherein the liquid refrigerant passes through the fluid container The principle of gas conversion expansion is converted into a working fluid with higher pressure and temperature and is delivered to the working fluid line;

a heat exchange member disposed inside the Dewar member, connected to the pressure vessel member by the working fluid line, the heat exchange member receiving work from the pressure vessel member Fluid and converting it into a working refrigerant, and delivering the working refrigerant to the working refrigerant line;

a freezing unit connected by the working refrigerant line and the heat exchange unit for receiving the working refrigerant, and a distal end portion of the freezing unit is a cold source releasing area of the working refrigerant.

In one embodiment, the cryoablation therapy system further includes a heater component and a rewarming passage, the rewarming passage being coupled to the pressure vessel component, the heater component for heating the rewarming conduit The working fluid is received and converted to a rewarming fluid at a temperature above room temperature.

In one embodiment, the cryoablation therapy system further includes a return air control component for preventing undesired condensation and reducing exhaust noise levels.

In one embodiment, the cryoablation therapy system further includes a control module that automates operation of the overall system.

In one embodiment, the process of filling the liquid container from the Dewar component to the pressure vessel component is an automated process that is driven and controlled by the control module.

In one embodiment, the pressure vessel component is a single-stage pressure vessel component, and the liquid filling process of the single-stage pressure vessel component is time-controlled, and the filling time set by each filling is less than five minutes. .

In one embodiment, the cryoablation therapy system is provided with a high pressure relief valve that defines a maximum allowable operating pressure level.

In one embodiment, the high pressure relief valve sets a maximum rated pressure of the pressure vessel, and the control module limits the pressure input by the user to exceed a maximum rated pressure.

In one embodiment, the pressure vessel utilizes an electrical heating source to produce a positive pressure to the fluid in the pressure vessel, the pressure having a maximum rated pressure of 100 bar and a maximum tolerance range of ± 10 bar.

In one embodiment, the pressure vessel is a variable pressurization system that produces different pressure levels of the working fluid based on user input.

In one embodiment of the present application, the cryoablation therapy system is further modified to have a multi-stage pressure vessel. The multi-stage pressure vessel system produces a continuous working fluid and delivers the working fluid to the freezing unit without interruption until the liquid refrigerant in the reservoir is exhausted.

In one embodiment, the pressure vessel component is a multi-stage pressure vessel component.

In a more preferred embodiment, the multi-stage pressure vessel component comprises two pressure vessels having an optimized volume such that the preparation time is less than or equal to the injection time.

In a more preferred embodiment, the pressure cycle and the infusion cycle of each of the two pressure vessels are synchronized in time to continuously deliver the working fluid.

In a more preferred embodiment, the synchronization of the pressure vessel is by setting a delay at the beginning of each pressure cycle, which is a preparation time period or an injection time period.

In a more preferred embodiment, the multi-stage pressure vessel component comprises three or more pressure vessels.

In a more preferred embodiment, the volume of the pressure vessel is optimized such that its preparation time does not have to be less than or equal to the injection time.

In a more preferred embodiment, the minimum infusion time for each of the pressure vessels is determined by the time taken to divide the preparation time by the number of pressure vessels.

In a more preferred embodiment, the pressure cycle and the infusion cycle in each of the pressure vessels are synchronized to continuously deliver the working fluid.

In a more preferred embodiment, a plurality of said pressure vessels operate in synchronism, and the beginning of the infusion cycle of one of said pressure vessels is the end of the infusion cycle of the preceding one of said pressure vessels.

DRAWINGS

FIG. 1 is a cryoablation system provided by an embodiment of the present application.

2 is a schematic illustration of the ablation unit of the cryoablation system of FIG. 1 having a single stage pressure vessel.

Figure 3 is a flow chart of the liquid filling cycle control of the pressure vessel.

Figure 4 is a flow chart of the pressure cycle control of the pressure vessel.

Figure 5 is a schematic illustration of the ablation unit in the cryoablation system shown in Figure 1, at which time the gas of the cryoablation system is returned to the Dewar.

6 is a schematic illustration of an ablation unit in the cryoablation system shown in FIG. 1 having a two-stage pressure vessel.

Figure 7 is a synchronized comparison of liquid pressure cycles in a two-stage pressure vessel.

Figure 8 is a synchronized comparison of liquid pressure cycles in a three-stage pressure vessel.

Figure 9 is a schematic illustration of a catheter in the cryoablation system of Figure 1.

detailed description

The preferred embodiments of the present application are described in detail below. This description only explains the basic principles of the embodiments of the present application, but the present application is not limited to this description. The protection scope of the present application is most precisely defined by the appended claims.

Referring to Figure 1, the present application provides a cryoablation system 10 that delivers cold and hot energy to the distal end of a freezing unit 600 using a liquid refrigerant such as nitrogen, helium, argon, helium, or the like. The cryoablation system 10 includes a cryoablation unit 100 to provide working refrigerant to the freezing unit 600. The cryoablation unit 100 includes a Dewar component, a pressure vessel component, and a heat exchange component, the Dewar component receiving liquid refrigerant from the outside; the pressure vessel component being disposed on the Dewar component Internally receiving liquid refrigerant from the Dewar component, wherein the liquid refrigerant is converted into a working fluid having a higher pressure and temperature by a liquid-gas conversion expansion principle, and Served to a working fluid line; the heat exchange component is disposed inside the Dewar component, connected to the pressure vessel component by the working fluid conduit, the heat exchange component receiving the pressure The working fluid of the container component is converted to a working refrigerant and the working refrigerant is delivered to the working refrigerant circuit. The freezing unit 600 is connected to the working refrigerant by the working refrigerant line and the heat exchange unit, and the distal end portion of the freezing unit is a cold source releasing area of the working refrigerant.

Referring to Figure 2, the cryoablation unit 100 has a single stage pressure vessel component disposed in a thermally insulated reservoir or Dewar. The cryoablation unit 100 includes a Dewar component, a single stage pressure vessel component, a heat exchange component, a heater component, a return air control component, and an evacuation component, all of which are controlled by a software control module (not shown) Controlling, wherein the Dewar component is used to store liquid refrigerant from the outside, the single-stage pressure vessel component receives liquid refrigerant from the Dewar component and converts it into a working fluid, The heat exchange component again cools the working fluid into a working refrigerant that converts the cold working fluid into a rewarming fluid.

The Dewar component includes a Dewar 102, a top plate 104, a seal 106, a heat insulating layer 108, a liquid filling valve 112, a liquid filling pipe 114, an exhaust valve 116, an exhaust pipe 124, and a primary pressure relief valve 118. Stage relief valve 120 and Dewar pressure sensor 122. The dewar 102 receives the liquid refrigerant from the outside through the liquid filling valve 112 and the liquid filling pipe 114. The gas in the Dewar 102 is vented through the exhaust valve 116 and the exhaust pipe 124. The outlet of the fill tube 114 is disposed near the bottom of the Dewar 102 to reduce evaporation of the liquid refrigerant during the filling process. The inlet of the exhaust pipe 124 is disposed near the top of the Dewar 102 to limit the maximum level 110 of refrigerant within the Dewar. Dewar 102 is an insulated storage that is designed to minimize the evaporation loss of the refrigerant under the influence of an external heat source. The Dewar fluid pressure P _D typically ranges from 5 psi to 250 psi. Higher fluid pressure dewars prevent more fluid from escaping or depleting as the fluid changes from a frozen state to a gas. However, components with higher pressure values are more expensive, meaning higher manufacturing costs. Low Dewar pressure provides more advantages, such as equipment that is safer to operate and less expensive. In this embodiment, the preferred Dewar fluid pressure P _D is 10 psi. The seal 106 and the top plate 104 in the Dewar component seal the Dewar 102 to maintain a positive pressure inside. The insulating layer 108 thermally insulates the top plate 104 to slow the evaporation of the refrigerant. The primary pressure relief valve 118 maintains the accumulated pressure in the Dewar below 10 psi as a primary safety element. The secondary relief valve 120 has a relief pressure of 15 psi as a secondary safety element to prevent overheating of the Dewar. Dewar pressure sensor 122 indicates the internal pressure of the Dewar and provides feedback. The Dewar component includes a sealed insulated storage or Dewar that is used to receive and store refrigerant and is thermally isolated from the outside to maintain a low fluid pressure. The fluid pressure of the Dewar is the driving force for the liquid refrigerant to enter the after-stage components such as the pressure vessel 134 from the Dewar. Also, liquid nitrogen in the Dewar 102 is used as a refrigerant to produce a working refrigerant.

The pressure vessel component includes a pressure vessel 134, a pressure heater 136, an intake pipe 138, an intake control valve 126, an intake check valve 128, a high pressure relief valve 146, a pressure sensor 148, an exhaust valve 170, and an exhaust muffler 172. And a pressure relief control valve 178. The pressure vessel 134 receives the refrigerant delivered from the Dewar 102 via the intake pipe 138, the intake control valve 126, and the intake check valve 128. The fluid pressure P _{D of the} Dewar provides energy to push the liquid refrigerant into the pressure vessel. During the filling cycle, the vaporized gas escapes from the pressure relief control valve 178. The process of filling the pressure vessel 134 from the Dewar 102 is an automated process controlled by a software control module. Referring to Figure 3, a flow chart of the liquid filling cycle control of the pressure vessel 134. When the Dewar pressure sensor 122 detects the Dewar fluid pressure P _D , the filling cycle begins. If the fluid pressure in the Dewar is less than or equal to 0 psi, the system will display a warning “Low Cryogen Pressure – Refill Dewar” to alert the operator. Once the Dewar pressure P _D and the pressure vessel P _C in the pressure vessel are both greater than 0 psi, the vent valve 170 opens to reduce the fluid pressure P _C in the pressure vessel to 0 psig or less. Once the P _C pressure reaches 0 psig or less, the pressure relief valve 178 and the intake control valve 128 are opened, and the exhaust valve 170 is closed to restart the refrigerant charging process. The filling cycle is determined by the filling time T _F , and the pressure vessel component design needs to weigh the filling time and volume. A larger volume requires a longer filling time. Smaller volumes require more cycles of filling cycles during the same time period. The object of the present application is to make the filling time T _F is minimized, each filling time T _F should be less than five minutes. Once the software time counter reaches the fill time T _F , the device will assume that the pressure vessel is full of refrigerant, at which point the intake check valve 128 and the pressure relief control valve 178 will close and then wait for the next pressurization cycle.

The pressure vessel component utilizes an electrical heating source to create a positive pressure for the fluid within it. A thermocouple (not shown) is provided inside the pressure heater 136 to map the pressure heater temperature T _H and the fluid temperature T _F inside the pressure vessel 134. Temperature readings and pressure readings from pressure sensor 148 are used to control the opening and closing of pressure heater 136, as further described below. A pressure heater is placed around the outer edge of the pressure vessel 134, which delivers hot steam to convert the liquid refrigerant to a gaseous state to create a positive pressure to the fluid. The upper internal pressure limit of the pressure vessel 134 is designed to be 100 bar. The pressure vessel fluid pressure P _C or the later-mentioned working fluid pressure P _W has a certain tolerance range, fluctuating between the lower pressure limit P _L and the upper pressure limit P _H . Among them, the working fluid pressure P _W allows a maximum tolerance range of ± 10 bar, and the upper pressure limit P _H will reach 100 bar. The purpose of this application is to design a pressurized system in which the working fluid pressure P _W can be varied based on user input data. The system allows the user to enter the desired pressure level and the software control system will automatically generate working fluid pressures with tolerances in the range of ±10 bar or less. In the pressure cycle, the software control system produces a positive pressure and adjusts the pressure in the pressure vessel component.

Referring to Figure 4, a pressure cycle control flow diagram in a pressure vessel component. The pressure cycle begins after the pressure sensor detects the working fluid pressure Pw in the pressure vessel 134. If Pw is above the upper pressure limit P _H , the vent valve 170 is opened, a portion of the working fluid is vented to the atmosphere for decompression, and the pressure heater will be shut down. When the fluid pressure Pw is lower than the upper pressure limit P _H , the exhaust valve is closed. When the working fluid pressure P _W falls below the lower pressure limit P _L , the fluid temperature T _{F is} lower than 0 ° C, at which time the temperature T _H of the pressure heater is lower than or equal to the highest rated temperature T _RH of the pressure heater, and the pressure is heated. The device will be turned on and heated. If the system detects that the temperature of the pressure heater is above T _RH , the pressure heater will be turned off. When the fluid pressure in the pressure vessel 134 is within the desired working fluid pressure range, the working fluid is used as a treatment. When the pressure vessel 134 runs out of internal fluid, the value of the fluid temperature T _F is greater than or equal to 0 ° C (in this case into the pressure vessel) and the filling cycle begins. The liquid remaining in the pressure vessel will be drained out for new filling.

When the pressure in the pressure vessel 134 rises, the monitoring system connects the primary and secondary safety elements in real time to prevent overpressure of the pressure vessel. Pressure sensor 148 collects working fluid pressure information and feeds it back to the software control system. When the pressure rises above the upper pressure upper limit P _H , the exhaust valve 170 is triggered to open, and when the pressure drops below the highest pressure, the exhaust valve 170 is closed. The exhaust valve 170 acts as a primary safety element to regulate the upper pressure limit and acts as a safety guard against overpressure. However, the exhaust valve 170 requires a power source to operate it. When the cryoablation unit 100 is de-energized, a mechanically operated high pressure relief valve 146 is used as the secondary safety element. The high pressure relief valve has only one pressure setting, which is the nominal internal pressure of the pressure vessel 134. The high pressure relief valve sets the maximum allowable operating pressure level, and the software control system limits the user to exceed this maximum rated pressure when entering the desired fluid pressure, which ensures that the high pressure relief valve can protect the cryoablation system from overpressure, And the system can be allowed to operate at any desired fluid pressure input value below the rated pressure of the pressure vessel.

When the fluid pressure in the pressure vessel 134 is within the desired range, the freeze/ablation cycle begins. In the refrigeration cycle, the working fluid flows from the pressure vessel component into the heat exchange component before flowing into the refrigeration unit 600. The heat exchange unit includes an outlet control valve 130, an optional outlet check valve 132, a heat exchange intake manifold 140, a heat exchanger 144, a heat exchanger outlet 142 and a delivery tube 162. In the refrigerating cycle command, the outlet control valve 130 is activated to open, allowing the working fluid in the pressure vessel 134 to flow into the heat exchanger 144 through the outlet control valve 130, the outlet check valve 132, and the intake manifold 140. The heat exchanger re-cools the working fluid using the liquid refrigerant in the Dewar 102 as a refrigerant. The heat exchanger component receives the working fluid and converts it into a working refrigerant, which is then delivered to the working refrigerant line. In a refrigerating cycle, the working refrigerant exits the heat exchanger into the outlet pipe 142, passes through the delivery pipe 162 into the joint X of the freezing unit 600, and the freezing unit 600 receives the working refrigerant at the joint X. The distal end portion of the freezing unit 600 is a cold source release region of the working refrigerant.

A rewarming passage is coupled to the pressure vessel component, the heater component for heating the working fluid received by the rewarming line and converting it to a rewarming fluid having a temperature above room temperature. In one embodiment, a switchable valve is disposed between the rewarming passage and the working fluid line. In the rewarming cycle, the working fluid flows into the heater component from the pressure vessel component before flowing into the freezing unit 600. The heater component converts it into a rewarming fluid after receiving the working fluid, and the rewarming fluid temperature is above room temperature. The (reheating) heater unit includes a rewarming control valve 150, a rewarming check valve 152, a rewarming heater 154, a rewarming exhaust valve 156, a rewarming pressure sensor 158, and a check valve 160. In the rewarming cycle command, the rewarming control valve 150 is activated to open, and the working fluid in the pressure vessel 134 flows through the rewarming control valve 150 and the rewarming check valve 152 into a built-in rewarming heater 154. The rewarming heater 154 heats the working fluid above room temperature. The fluid changes from the rewarming heater 154 to a rewarming fluid, and the temperature of the rewarming fluid is controlled to have a high upper temperature limit which is approximately equal to the highest rated temperature T _{RH of the} pressure heater. However, for safety reasons, the temperature of the rewarming fluid should not exceed the temperature that is unsafe for the human body. The rewarming heater integrates a thermocouple (not shown) to detect the temperature of the rewarming heater and the temperature of the rewarming fluid. The heater temperature sensor is used to ensure that the operating temperature of the reheat heater is lower than the maximum rated temperature T _{RH of the} pressure heater to prevent overheating. The software control module uses a rewarming fluid temperature sensor to control the opening and closing of the heater so that the rewarming temperature is maintained between room temperature and T _RH . A rewarmable exhaust valve 156 is used to exhaust fluid within the system at the end of each refrigeration cycle and rewarming cycle. The rewarmable exhaust valve 156 can also be used as a safety element when the rewarping pressure sensor 158 detects an overpressure.

During the cryoablation treatment cycle, the working fluid is returned from the freezing unit 600 (eg, a catheter) into the cryoablation unit 100. The return air control unit receives the fluid flowing back from the freezing unit 600 at the X point. The return air control unit includes a return air passage 164, a reheat heat exchanger 166, and a return air silencer 168. The returning fluid first enters the return air passage 164 and then enters the rewarming heat exchanger 166. Inside the rewarming heat exchanger 166, the return air temperature rises to near room temperature and is discharged to the atmosphere through the return muffler 168. The purpose of the rewarming heater is to eliminate condensation water droplets caused by low temperatures and to have a slow expansion of the return air to reduce the pressure. The return air silencer helps to reduce the noise emitted by the gas to the atmosphere. As mentioned earlier, there is also a design that can be integrated into the device in place of the return air control component described above. Referring to Figure 5, a return air passage 164A receives the return air from point X and discharges it into the gas space within the Dewar 102. This gas space is at the top of the Dewar 102, which is above the opening of the exhaust pipe 124, and the opening of the exhaust pipe 124 is defined by the highest rated level 110 of the charged refrigerant. This alternative design eliminates the need for rewarming heat exchangers and return air silencers. However, the return air pressure is high, so the Dewar 102 and the components that make up the Dewar component are required to have a higher rated pressure.

The dashed line 176 refers to thermally insulating the cryoablative fluid from its external environment through an optional vacuum insulation component to avoid damage to the non-frozen ablation portion of the patient. The vacuum of the vacuum insulation system is produced by the ultra high vacuum system 174. The vacuum insulation system adiabatically protects the delivery tube 162, the check valve 160, the X point, the freezing unit 600, and the return air tube 164. The secondary cooled fluid from the Dewar 102 is protected from thermal insulation from the top plate 104 to the X point on the cryoablation unit 100. The working refrigerant enters the freezing unit 600 at the X point through the conveying pipe 162, and then returns from the X point to the return pipe 164.

In one embodiment, the present application provides a software controlled cryoablation therapy system comprising a cryoablation unit and a catheter, the cryoablation unit comprising an insulated reservoir or Dewar, a pressure chamber, and a catheter Heat exchanger and heater, a vacuum insulation system, a return air sub-assembly and a software control module. The heat insulating reservoir or Dewar obtains a fluid refrigerant from the outside; the pressure chamber generates a working fluid from the fluid refrigerant; the heat exchanger and the heater convert the working fluid into a working refrigerant required for treatment or a rewarming fluid that insulates heat transfer from the working refrigerant and the outside to protect a non-frozen ablation zone of the patient; the return gas secondary component blocks unwanted condensate and reduces noise; the software control module ( Not shown) for automatic control of the operation of the system. The catheter is coupled to the cryoablation unit to receive the working refrigerant delivered from the cryoablation unit and direct the returned fluid back to the cryoablation unit. The distal portion of the catheter delivers working refrigerant to the site where the body needs treatment.

The cryoablation therapy system automatically fills the fluid refrigerant from the adiabatic reservoir into a single stage pressure vessel and then uses thermal energy to vaporize it into a working fluid having a higher pressure and temperature. A software control module controls the flow of working fluid. In a refrigerating cycle, the working fluid flows through a heat exchanger that is immersed in the liquid refrigerant and is again cooled to become a working refrigerant. In the rewarming cycle, a built-in heater is used to convert the working fluid into a (hot) rewarming fluid. The software control module automatically adjusts fluid pressure, monitors operational status, directs fluid, and triggers an emergency stop procedure upon detection of an unsafe operating condition. The cryoablation unit uses one type of refrigerant, preferably liquid nitrogen. Liquid nitrogen is used not only as a working fluid but also as a refrigerant.

The above embodiment describes the design of a single stage pressure vessel. The working fluid in the pressure vessel is capable of providing continuous flow until exhaustion. If it is necessary to constantly fill during the treatment, the preparation time or the filling time or the pressing time is very short. But it is difficult to reduce the preparation time to be short enough. Then, increasing the volume of the pressure vessel to accommodate a working fluid sufficient for one cryotherapy seems to be a good choice, but this will result in a large space for the entire system, which is not practical for a hospital environment. In still another alternative, a second embodiment of the present application includes a multi-stage pressure vessel design having a plurality of smaller pressure vessels to overcome the disadvantages of a single stage pressure vessel. As will be described in further detail below, the multi-stage pressure vessel is capable of continuously delivering the working fluid without stopping and refilling during the treatment cycle.

Referring to Figure 6, a cryoablation unit having a two-stage pressure vessel. This cryoablation unit is structurally identical to the single stage pressure vessel design shown in FIG. The difference is that it has two pressure vessels and associated parts, as indicated by the suffixes A and B on the figure. The two-stage pressure vessel is designed such that when one pressure vessel is filled, the other pressure vessel is delivering the working fluid. The volume of the two-stage pressure vessel is smaller than that of the single-stage pressure vessel. A smaller volume requires less refrigerant fill time and more pressure vessels can be placed in a given space. The volume of the pressure vessel is optimized. The preparation time is the time taken for the filling time and the pressure of the pressurized refrigerant to become the working fluid. The infusion time is the time required to drain all of the working fluid in the pressure vessel each time. The preparation time should be less than or equal to the injection time. When the injection time is greater than or equal to the filling time, the pressure vessel can work continuously in synchronization to provide a continuous working fluid. As shown in Figure 7, the two-stage pressure vessel is filled and pressure circulated. Figure 7 shows that the pressure vessels 1 and 2 operate synchronously, with a delay at the beginning of each pressure cycle, which is a preparation time period or an injection time period. Since the preparation time (injection time of the two pressure vessels) is the same, continuous pressure cycling, or continuous flow of fluid, is possible.

Similarly, a multi-stage pressure vessel system can also be designed with three or more pressure vessels (not shown). In this example, the volume of the pressure vessel is optimized, wherein the preparation time of each vessel need not be less than or equal to its injection time. Instead, the preparation time of each pressure vessel is divided by the number of pressure vessels, which is the minimum injection time of a pressure vessel. The injection cycle of each pressure vessel is synchronized to deliver a continuous fluid, as shown in FIG. For a three-stage pressure vessel system, when the minimum injection time for each pressure vessel is determined, the beginning of each pressure vessel injection cycle is the end of the previous pressure vessel injection cycle. If the injection time is greater than the minimum value, the pressure cycle synchronization work overlaps (injection), which ensures that the required working fluid can flow continuously.

The above embodiment includes one or more pressure vessels that are placed in the gas space of the Dewar 102. Although in a preferred embodiment, the pressure vessel can also be placed outside of the Dewar 102 (not shown) or immersed in refrigerant near the bottom of the Dewar 102 (not shown). Regardless of where the pressure vessel is placed, the pressure vessel of the present application can be automatically controlled and operated by a software control module (not shown) or other control means such as a microprocessor, an embedded system, an industrial computer, and the like. . The pressure vessel receives the refrigerant from the Dewar component and converts it into a working fluid. The freezing unit is coupled to a freezing ablation unit that receives the working refrigerant after passing through the heat exchanger component during the refrigeration cycle or the rewarming fluid after the refrigeration unit receives the heater component during the rewarming cycle. The fluid discharged from the freezing unit is returned to the cryoablation unit. The entire cryoablation system 10 utilizes thermal energy to generate a positive pressure from the liquid refrigerant, control the temperature of the fluid, and deliver it to the freezing unit 600 for therapeutic use. The cryoablation therapy system of the present application receives an externally filled liquid cryogen and automatically converts the liquid cryogen into a therapeutic working fluid without the need for an external gas canister to provide a continuous gas.

Freezing unit

Referring to Figure 9, a schematic diagram of a typical refrigeration unit 600. The freezing unit 600 is preferably a conduit, and the freezing unit is coupled to the cryoablation system 10 at point X. The freezing unit has a thermally insulated section 206, a freezing section 208, and a distal head 210. Thermal insulation section 206 includes an X point. The delivery pipe 202 of the freezing unit and the return pipe 204 of the freezing unit are connected to the X point. The space between the thermal insulation section 206 and the intersection with the freezing section 208 is thermally insulated by vacuuming the vacuum system 174.

Freezing section 208 is a non-adiabatic section. The freezing unit 600 is connected to the freezing passage through the X point for receiving the working refrigerant, and the freezing energy is provided by the conveying pipe and the return pipe, and the working fluid is delivered to the treatment site through the freezing portion 508 of the freezing unit 600, and the freezing unit 600 The distal portion is the cold source release area of the working refrigerant. The chilled energy is either in direct contact with the body tissue to be treated or by a medical balloon or other heat transfer medium wrapped in an equivalent material. The heat transfer medium can be physiological saline or other biocompatible liquid that is not volatile at room temperature. The delivery tube 202 and the return air tube 204 of the freezing unit 600 extend beyond the thermal insulation section 206 into the freezing section 208 and partially into the head 210.

The head 210 is extended from the freezing section 208. The head end is typically designed to be soft and smooth so that the freezing unit can pass through a tortuous path without damaging the surrounding tissue.

The above description is a preferred embodiment of the present application, and it is to be understood that there are many alternative modifications that may be made without departing from the spirit and scope of the application. All modifications within.

Claims

A cryoablation therapy system comprising:

a Dewar component that receives liquid refrigerant from the outside;

a pressure vessel component disposed inside the Dewar component to receive liquid refrigerant from the Dewar component, wherein the liquid refrigerant passes through the fluid container The principle of gas conversion expansion is converted into a working fluid with higher pressure and temperature and is delivered to the working fluid line;

a heat exchange member disposed inside the Dewar member, connected to the pressure vessel member by the working fluid line, the heat exchange member receiving work from the pressure vessel member Fluid and converting it into a working refrigerant, and delivering the working refrigerant to the working refrigerant line;

a freezing unit connected by the working refrigerant line and the heat exchange unit for receiving the working refrigerant, and a distal end portion of the freezing unit is a cold source release of the working refrigerant region.
A cryoablation treatment system according to claim 1, wherein said cryoablation treatment system further comprises a heater member and a rewarming passage, said rewarming passage being coupled to said pressure vessel member, said heater member And heating the working fluid received by the rewarming line and converting it into a rewarming fluid having a temperature higher than room temperature.
The cryoablation therapy system of claim 1, wherein the cryoablation therapy system further comprises a return air control component for preventing undesired condensation and reducing exhaust noise levels.
The cryoablation therapy system of claim 1 wherein said cryoablation therapy system further comprises a control module that automates operation of the entire system.
A cryoablation therapy system according to claim 4, wherein the process of filling the liquid container from the Dewar component to the pressure vessel component is an automated process driven and controlled by the control module.
The cryoablation treatment system according to claim 5, wherein the pressure vessel component is a single-stage pressure vessel component, and the liquid filling process of the single-stage pressure vessel component is controlled by time, and is set for each liquid filling. The set filling time is less than five minutes.
A cryoablation therapy system according to claim 4, wherein said cryoablation therapy system is provided with a high pressure relief valve that defines a maximum allowable operating pressure level.
A cryoablation treatment system according to claim 7, wherein said high pressure relief valve sets a maximum rated pressure of said pressure vessel, and said control module limits a pressure input by a user to exceed a maximum rated pressure.
The cryoablation treatment system according to claim 1, wherein the pressure vessel uses an electric heating source to generate a positive pressure to the fluid in the pressure vessel, the pressure having a maximum rated pressure of 100 bar and a maximum tolerance range of ±10 bar.
A cryoablation therapy system according to claim 1 wherein said pressure vessel is a variable pressurization system capable of producing different pressure levels of said working fluid based on user input .
A cryoablation therapy system according to claim 1, wherein the pressure vessel component is a multi-stage pressure vessel component.
A cryoablation treatment system according to claim 11, wherein said multi-stage pressure vessel component comprises two pressure vessels having an optimized volume such that the preparation time is less than or equal to the injection time.
A cryoablation treatment system according to claim 12, wherein the pressure cycle and the infusion cycle of each of the two pressure vessels are synchronized in time to continuously deliver the working fluid.
A cryoablation therapy system according to claim 13 wherein the synchronization of the pressure vessel is by setting a delay at the beginning of each pressure cycle, the delay being a preparation time period or an infusion time period.
A cryoablation therapy system according to claim 11 wherein said multi-stage pressure vessel component comprises three or more pressure vessels.
A cryoablation treatment system according to claim 15, wherein the volume of the pressure vessel is optimized such that the preparation time does not have to be less than or equal to the injection time.
A cryoablation treatment system according to claim 16, wherein the minimum infusion time of each of said pressure vessels is determined by the time taken to divide the preparation time by the number of said pressure vessels.
A cryoablation treatment system according to claim 15, wherein the pressure cycle and the infusion cycle in each of said pressure vessels are synchronized to continuously deliver said working fluid.
A cryoablation treatment system according to claim 18, wherein a plurality of said pressure vessels operate in synchronism, and the beginning of a liquid injection cycle of said one pressure vessel is the end of a liquid injection cycle of said previous pressure vessel.