Composite high and low temperature thermal ablation system

Abstract

This invention relates to a composite high and low temperature thermal ablation system, and pertains to the field of ablation technology. The composite high and low temperature thermal ablation system of this invention adjusts the pressure of the working fluid storage tank by controlling the number and diameter of the ablation needles connected in the pipeline, and adjusts the opening of the phase separation valve to maintain the phase separation valve at the target temperature. This allows for rapid cooling with minimal consumption of working fluid, regardless of the combination of ablation needles.

Description

[0001] This application is a divisional application of Chinese Patent CN 202411472318.X, filed on October 22, 2024, entitled "Composite High and Low Temperature Cold and Heat Ablation System and Control Method Thereof". Technical Field

[0002] This invention relates to the field of ablation technology, and particularly to a composite high and low temperature cold and hot ablation system. Background Technology

[0003] A combined high-low temperature cryogenic ablation system typically includes a working fluid storage tank, connecting pipelines, and ablation needles. After precooling, the working fluid in the storage tank is delivered to the ablation needles via the connecting pipelines, where it performs the ablation operation. The number and diameter of the ablation needles connected in the pipelines affect the flow rate of the working fluid within the needles, which in turn affects the temperature of the working fluid. This results in significant differences in the time required for precooling and ablation operations, the amount of working fluid consumed, and the effectiveness of the ablation operation. Summary of the Invention

[0004] This invention provides a composite high and low temperature thermal ablation system that can achieve rapid cooling with minimal use of working fluid, regardless of the combination of ablation needles.

[0005] According to a first aspect of the present invention, the present invention provides a composite high and low temperature thermal ablation system, comprising a working fluid storage tank, a phase separation valve, a connecting pipeline, an ablation needle, and a controller, wherein the connecting pipeline is used to connect to the working fluid storage tank, the phase separation valve, and the ablation needle, and the controller is connected to the working fluid storage tank, the phase separation valve, and the ablation needle respectively;

[0006] The controller is configured to perform the following steps:

[0007] 100: Determine if the number of ablation needles connected in the connecting pipeline is 0. If yes, proceed to step 200; otherwise, proceed to step 300.

[0008] 200: Adjust the pressure of the working fluid storage tank from P3 to P1-ΔP2, and maintain the phase separation valve at the target temperature T3 to T4;

[0009] 300: Determine if the number of ablation needles connected in the connecting pipeline is 1. If yes, proceed to step 400; otherwise, proceed to step 500.

[0010] 400: Determine whether the diameter of the ablation needle connected in the connecting pipeline is ≥d1. If yes, adjust the pressure of the working fluid storage tank to P1 and keep the phase separation valve at the target temperature T3 to T4. If no, proceed to step 401.

[0011] 401: Determine whether the diameter of the ablation needle connected in the connecting pipeline is between d2 and d1. If yes, adjust the pressure of the working fluid storage tank to P2 and keep the phase separation valve at the target temperature T3 to T4. If no, proceed to step 402.

[0012] 402: Determine whether the diameter of the ablation needle connected in the connecting pipeline is <d2. If so, adjust the pressure of the working fluid storage tank to P3 and keep the phase separation valve at the target temperature T1 to T2.

[0013] 500: Determine whether the diameter of the ablation needle connected in the connecting pipeline is ≥d2. If yes, adjust the pressure of the working fluid storage tank to P1 and keep the phase separation valve at the target temperature T3 to T4. If no, proceed to step 501.

[0014] 501: Determine whether the diameter of the ablation needle connected in the connecting pipeline is <d2. If so, adjust the pressure of the working fluid storage tank to P2 and keep the phase separation valve at the target temperature T2 to T3.

[0015] Where ΔP2<P1<P2<P3;T1<T2<T3<T4。

[0016] In one implementation, during step S400 or S500, when the pressure of the working fluid storage tank is adjusted to P1:

[0017] If the pressure in the working fluid storage tank is less than P1-ΔP2, the controller will fully open the pressure boosting valve on the working fluid storage tank and fully close the venting valve on the working fluid storage tank.

[0018] If the pressure in the working fluid storage tank is between P1-ΔP2 and P1+ΔP2, the controller will gradually close the pressure boosting valve on the working fluid storage tank.

[0019] If the pressure in the working fluid storage tank is greater than P1+ΔP2, the controller will gradually open the vent valve on the working fluid storage tank.

[0020] If the pressure of the working fluid storage tank is less than P1-ΔP1, the controller will completely close the vent valve on the working fluid storage tank, thereby adjusting the pressure of the working fluid storage tank to P1.

[0021] Wherein, P1 is the pressure of the working fluid storage tank, ΔP1 and ΔP2 are the pressure changes of the working fluid storage tank, and ΔP1 < ΔP2.

[0022] In one embodiment, during steps S200, S400, 401, or S500, when the target temperature of the phase separation valve is T3 to T4:

[0023] If the current temperature of the phase separation valve is ≥ T5, the controller will adjust the opening of the phase separation valve to 100%.

[0024] If T4 ≤ the current temperature of the phase separation valve < T5, then the controller will adjust the opening degree of the phase separation valve to K3.

[0025] If T3 ≤ the current temperature of the phase separation valve < T4, then the controller will adjust the opening degree of the phase separation valve to K4, where K4 > K3;

[0026] If the current temperature of the phase separation valve is ≤ T3, the controller will adjust the opening of the phase separation valve to 0%, where T3 < T4 < T5.

[0027] Where k is a constant, and its value ranges from 1 to k to 1.2.

[0028] In one implementation, K3 and K4 respectively satisfy the following expressions:

[0029]

[0030] In one implementation, during step 401, when the pressure of the working fluid storage tank is adjusted to P2:

[0031] If the pressure in the working fluid storage tank is less than P2-ΔP2, the controller will fully open the pressure boosting valve on the working fluid storage tank and fully close the venting valve on the working fluid storage tank.

[0032] If the pressure in the working fluid storage tank is between P2-ΔP2 and P2+ΔP2, the controller will gradually close the pressure boosting valve on the working fluid storage tank.

[0033] If the pressure in the working fluid storage tank is greater than P2-ΔP2, the controller will gradually open the vent valve on the working fluid storage tank.

[0034] If the pressure of the working fluid storage tank is less than P2-ΔP1, the controller will completely close the vent valve on the working fluid storage tank, thereby adjusting the pressure of the working fluid storage tank to P2.

[0035] Wherein, ΔP1 and ΔP2 are the pressure changes in the working fluid storage tank, respectively, and ΔP1 < ΔP2.

[0036] In one implementation, during step 501, the phase separation valve is maintained at the target temperature T2 to T3:

[0037] If the current temperature of the phase separation valve is ≥ T3, the controller will adjust the opening of the phase separation valve to 100%.

[0038] If T2 ≤ the current temperature of the phase separation valve < T3, then the controller will adjust the opening degree of the phase separation valve to K2;

[0039] If the current temperature of the phase separation valve is less than T2, the controller will adjust the opening of the phase separation valve to 0%, where T2 < T3;

[0040] Wherein, K2 satisfies the following expression:

[0041]

[0042] k is a constant, and its value range is 1≤k≤1.2.

[0043] In one implementation, during step 402, when the pressure of the working fluid storage tank is adjusted to P3:

[0044] If the pressure in the working fluid storage tank is less than P3-2ΔP2, the controller will fully open the pressure boosting valve on the working fluid storage tank and fully close the venting valve on the working fluid storage tank.

[0045] If the pressure in the working fluid storage tank is between P3-2ΔP2 and P3-ΔP2, the controller will gradually close the pressure boosting valve on the working fluid storage tank.

[0046] If the pressure in the working fluid storage tank is greater than P3-ΔP2, the controller will gradually open the vent valve on the working fluid storage tank.

[0047] If the pressure in the working fluid storage tank is less than P3-ΔP3, the controller will completely close the vent valve on the working fluid storage tank; thereby, the controller will adjust the pressure in the working fluid storage tank to P3.

[0048] Wherein, P1, P2, and P3 are the pressures of the working fluid storage tank, P1 < P2 < P3; ΔP1, ΔP2, and ΔP3 are the pressure changes of the working fluid storage tank, ΔP1 < ΔP2 < ΔP3.

[0049] In one implementation, in step 402, the phase separation valve is maintained at the target temperature T1 to T2:

[0050] If the current temperature of the phase separation valve is ≥ T2, the controller will adjust the opening of the phase separation valve to 100%.

[0051] If T1 ≤ the current temperature of the phase separation valve < T2, then the controller will adjust the opening degree of the phase separation valve to K1;

[0052] If the current temperature of the phase separation valve is less than T1, the controller will adjust the opening of the phase separation valve to 0%, where T1 < T2;

[0053] Wherein, K1 satisfies the following expression:

[0054]

[0055] k is a constant, and its value range is 1≤k≤1.2.

[0056] In one implementation, during step 200, when the pressure of the working fluid storage tank is adjusted from P3 to P1-ΔP2:

[0057] If the pressure in the working fluid storage tank is less than P1-2ΔP2, the controller will fully open the pressure boosting valve on the working fluid storage tank and fully close the venting valve on the working fluid storage tank.

[0058] If the pressure in the working fluid storage tank is between P1-2ΔP2 and P1, the controller will gradually close the pressure boosting valve on the working fluid storage tank.

[0059] If the pressure in the working fluid storage tank is greater than P1, the controller will gradually open the vent valve on the working fluid storage tank.

[0060] If the pressure of the working fluid storage tank is less than P1-ΔP3, the vent valve on the working fluid storage tank is completely closed, thereby the controller adjusts the pressure of the working fluid storage tank to P1-ΔP2.

[0061] Wherein, P2 and P3 are the pressures of the working fluid storage tank, ΔP3 is the pressure change of the working fluid storage tank, and ΔP1 < ΔP2 < ΔP3 < P1 < P3.

[0062] In one implementation, P1 is 650 kPa, P2 is 850 kPa, P3 is 1000 kPa, ΔP1 is 5 kPa to 30 kPa, ΔP2 is 10 kPa to 50 kPa, and ΔP3 is 30 kPa to 80 kPa.

[0063] Compared with the prior art, the advantages of the present invention are that the number and diameter of the ablation needles connected in the controller connection pipeline adjust the pressure of the working fluid storage tank and adjust the opening of the phase separation valve so that the phase separation valve is kept at the target temperature, thereby achieving the purpose of rapid cooling with the least amount of working fluid consumption under various combinations of ablation needles. Attached Figure Description

[0064] The invention will now be described in more detail with reference to embodiments and the accompanying drawings.

[0065] Figure 1 This is a flowchart of the control method of the composite high and low temperature thermal ablation system in an embodiment of the present invention;

[0066] Figure 2 yes Figure 1 Flowchart for step 200;

[0067] Figure 3 yes Figure 1 Flowchart for step 403;

[0068] Figure 4 yes Figure 1 Flowchart for step 404;

[0069] Figure 5 yes Figure 1 Flowchart for step 405;

[0070] Figure 6 yes Figure 1 The flowchart for step 502. Detailed Implementation

[0071] The invention will now be further described with reference to the accompanying drawings.

[0072] This invention provides a composite high and low temperature cold and hot ablation system, including a working fluid storage tank, a phase separation valve, a connecting pipeline, an ablation needle, and a controller. The connecting pipeline is used to connect to the working fluid storage tank, the phase separation valve, and the ablation needle, and the controller is connected to the working fluid storage tank, the phase separation valve, and the ablation needle respectively.

[0073] The working fluid storage tank of the present invention can be, for example, a cold tank for storing cold working fluids such as liquid nitrogen. Its structure can adopt various implementation methods in the prior art. Similarly, the phase separation valve, connecting pipeline and ablation needle can also adopt various implementation methods in the prior art.

[0074] The controller of the present invention is configured to adjust the pressure of the working fluid storage tank according to the number of ablation needles connected in the connecting pipeline and the diameter of the ablation needles connected in the connecting pipeline.

[0075] The concept of this invention lies in designing different thresholds based on different combinations of ablation needle diameters and numbers, thereby achieving rapid cooling in the most efficient way (e.g., using liquid nitrogen) regardless of how the ablation needles are combined. Specifically, when the number of ablation needles connected in the pipeline is one, there are three cases.

[0076] The first scenario is: the number of ablation needles connected in the connecting tubing is 1, and the diameter of the ablation needle is ≥d1. Here, d1 can be, for example, 2.6mm. The fact that the diameter of the ablation needle connected in the connecting tubing is ≥d1 indicates that the diameter of the ablation needle connected in the connecting tubing may be 2.6mm or larger.

[0077] It should be noted that the diameter of the ablation needle refers to the diameter of the exit point at the tip of the ablation needle.

[0078] In the first case described above, the controller is configured to control the pressure boosting valve and / or venting valve on the working fluid storage tank, thereby adjusting the pressure of the working fluid storage tank to P1.

[0079] The controller regulates the pressure (working pressure) of the working fluid storage tank by controlling the opening and closing of the pressure boosting valve or the gradual opening and closing of the venting valve. The pressure boosting valve and venting valve can be electrically connected to the controller, which is configured to send commands to the valve to cause corresponding actions by relevant components, thereby adjusting the opening degree of the valve, such as fully opening (100%) or fully closing (0%).

[0080] For example, in the first case, the controller is configured such that when the pressure in the working fluid storage tank is less than P1-ΔP2, the controller fully opens the pressure boosting valve and fully closes the venting valve; when the pressure in the working fluid storage tank is between P1-ΔP2 and P1+ΔP2, the controller gradually closes the pressure boosting valve (at which point the venting valve is fully closed); when the pressure in the working fluid storage tank is greater than P1+ΔP2, the controller gradually opens the venting valve; when the pressure in the working fluid storage tank is less than P1-ΔP1, the controller fully closes the venting valve, thereby adjusting the pressure in the working fluid storage tank to P1; where ΔP1 < ΔP2.

[0081] More specifically, P1 can be, for example, 650 kPa, P2 can be, for example, 850 kPa, the value range of ΔP1 can be, for example, 5 kPa to 30 kPa, and the value range of ΔP2 can be, for example, 10 kPa to 50 kPa. The smaller the values ​​of ΔP1 and ΔP2, the higher the adjustment accuracy. Optionally, ΔP1 is 30 kPa and ΔP2 is 50 kPa; or alternatively, ΔP1 is 10 kPa and ΔP2 is 30 kPa; or alternatively, ΔP1 is 5 kPa and ΔP2 is 10 kPa. In the first case, the target pressure of the working fluid storage tank is 650 kPa. Under this target pressure, the temperature fed back by the phase separation valve can reach the target temperature within 10 minutes, which is much less than the preparation time before the ablation operation, thereby improving the efficiency of the ablation operation.

[0082] The following explanation uses ΔP1 as an example of 30 kPa and ΔP2 as an example of 50 kPa.

[0083] Understandably, in the first case, the target pressure is P1 (650 kPa), P1-ΔP2 is 600 kPa, P1+ΔP2 is 700 kPa, and P1-ΔP1 is 620 kPa.

[0084] When the pressure of the working medium storage tank is less than 600 kPa, the controller controls the pressure boosting valve to fully open and the venting valve to fully close, thus increasing the pressure of the working medium storage tank. When the pressure of the working medium storage tank is between 600 kPa and 700 kPa, the controller controls the pressure boosting valve to gradually close. When the pressure of the working medium storage tank is greater than 700 kPa, the controller controls the venting valve to gradually open, thus depressurizing the working medium storage tank to reduce its pressure. When the pressure of the working medium storage tank is less than 620 kPa, the controller controls the venting valve to fully close, thereby dynamically regulating the pressure of the working medium storage tank to 650 kPa.

[0085] During the above adjustment process, if the pressure in the working fluid storage tank is between 600 kPa and 700 kPa, it indicates that it is close to the target pressure. Therefore, the controller can gradually close the pressure boosting valve to gradually approach the target temperature. In other words, when adjusting the pressure of the working fluid storage tank, it is not directly compared with the target pressure, but rather compared with the lower limit (e.g., 600 kPa) and upper limit (e.g., 700 kPa) of the target pressure range. This ensures that the pressure in the working fluid storage tank gradually approaches the target temperature, taking into account the time required for both pressurization and depressurization, and avoids frequent opening / closing of the pressure boosting valve or venting valve, which could cause system turbulence.

[0086] The second scenario is: the number of ablation needles connected in the connecting tubing is 1, and the diameter of the ablation needle is between d2 and d1. Here, d2 can be, for example, 2mm, and the diameter of the ablation needle connected in the connecting tubing being between d2 and d1 indicates that the diameter of the ablation needle connected in the connecting tubing may be 2mm or 2.5mm, etc.

[0087] In the second case described above, the controller is configured to control the pressure boosting valve and / or venting valve on the working fluid storage tank, thereby adjusting the pressure of the working fluid storage tank to P2, where P1 < P2.

[0088] The controller regulates the pressure (working pressure) of the working medium storage tank by controlling the opening or closing of the pressure boosting valve on the working medium storage tank, or by controlling the gradual opening or closing of the venting valve on the working medium storage tank.

[0089] For example, in the second case, the controller is configured such that when the pressure in the working fluid storage tank is less than P2-ΔP2, the booster valve is fully opened and the vent valve is fully closed; when the pressure in the working fluid storage tank is between P2-ΔP2 and P2+ΔP2, the booster valve is gradually closed; when the pressure in the working fluid storage tank is greater than P2-ΔP2, the vent valve is gradually opened; and when the pressure in the working fluid storage tank is less than P2-ΔP1, the vent valve is fully closed, thereby adjusting the pressure in the working fluid storage tank to P2; where ΔP1 < ΔP2.

[0090] More specifically, d2 can be, for example, 2 mm, and P2 can be, for example, 850 kPa.

[0091] Understandably, in the second case, the target pressure is P2 (850 kPa), P2-ΔP2 is 800 kPa, P2+ΔP2 is 900 kPa, and P2-ΔP1 is 820 kPa.

[0092] In other words, in the second scenario, the target pressure of the working fluid storage tank is 850 kPa. When the pressure of the working fluid storage tank is less than 800 kPa, the controller fully opens the pressure boosting valve and fully closes the venting valve, allowing the working fluid storage tank to be pressurized to increase its pressure. When the pressure of the working fluid storage tank is between 800 kPa and 900 kPa, the controller gradually closes the pressure boosting valve. When the pressure of the working fluid storage tank is greater than 800 kPa, the controller gradually opens the venting valve, allowing the working fluid storage tank to be depressurized to reduce its pressure. When the pressure of the working fluid storage tank is less than 820 kPa, the controller fully closes the venting valve, thereby dynamically adjusting the pressure of the working fluid storage tank to 850 kPa.

[0093] During the above adjustment process, if the pressure in the working fluid storage tank is between 800 kPa and 900 kPa, it indicates that it is close to the target pressure. Therefore, the controller can gradually close the pressure boosting valve to gradually approach the target temperature. In other words, when adjusting the pressure of the working fluid storage tank, it is not directly compared with the target pressure, but rather compared with the lower limit (e.g., 800 kPa) and upper limit (e.g., 900 kPa) of the target pressure range. This ensures that the pressure in the working fluid storage tank gradually approaches the target temperature, taking into account the time required for both pressurization and depressurization, and avoids frequent opening / closing of the pressure boosting valve or venting valve, which could cause system turbulence.

[0094] The third scenario is: the number of ablation needles connected in the connecting tubing is 1, and the diameter of the ablation needle is < d2. Here, d2 can be, for example, 2 mm, and the diameter of the ablation needle connected in the connecting tubing < d2 indicates that the diameter of the ablation needle connected in the connecting tubing may be 1.7 mm.

[0095] In the third scenario described above, the controller adjusts the pressure of the working fluid storage tank to P3.

[0096] The controller regulates the pressure (working pressure) of the working medium storage tank by controlling the opening or closing of the pressure boosting valve on the working medium storage tank, or by controlling the gradual opening or closing of the venting valve on the working medium storage tank.

[0097] For example, in the third case, when the pressure of the working fluid storage tank is less than P3-2ΔP2, the pressure boosting valve is fully opened and the venting valve is fully closed; when the pressure of the working fluid storage tank is between P3-3ΔP2 and P3-ΔP2, the pressure boosting valve is gradually closed; when the pressure of the working fluid storage tank is greater than P3-ΔP2, the venting valve is gradually opened; when the pressure of the working fluid storage tank is less than P3-ΔP3, the venting valve is fully closed, thereby adjusting the pressure of the working fluid storage tank to P2; where P1 < P2 < P3; ΔP1 < ΔP2 < ΔP3.

[0098] More specifically, P3 can be, for example, 1000 kPa, and the range of ΔP3 can be, for example, 30 kPa to 80 kPa. Optionally, ΔP3 can be 80 kPa, ΔP3 can be 50 kPa, or ΔP3 can be 30 kPa.

[0099] In other words, in the third scenario, the target pressure of the working fluid storage tank is 1000 kPa. When the pressure of the working fluid storage tank is less than 900 kPa, the controller controls the pressure boosting valve to fully open and the venting valve to fully close, allowing the working fluid storage tank to be pressurized to increase its pressure. When the pressure of the working fluid storage tank is between 850 kPa and 950 kPa, the controller controls the pressure boosting valve to gradually close. When the pressure of the working fluid storage tank is greater than 950 kPa, the controller controls the venting valve to gradually open, allowing the working fluid storage tank to be depressurized to reduce its pressure. When the pressure of the working fluid storage tank is less than 920 kPa, the controller controls the venting valve to fully close, thereby dynamically adjusting the pressure of the working fluid storage tank to 1000 kPa.

[0100] During the above adjustment process, since the maximum pressure of the working fluid storage tank is set to 1000 kPa, the lower limit of the target pressure range can be 850 kPa, and the upper limit (which cannot exceed the maximum pressure) can be 950 kPa.

[0101] Similarly, if the pressure in the working fluid storage tank is between 850 kPa and 950 kPa, it indicates that it is already close to the target pressure. Therefore, the controller can gradually close the pressure boosting valve to gradually approach the target temperature. In other words, when adjusting the pressure in the working fluid storage tank, it is not directly compared with the target pressure, but rather with the lower limit (e.g., 850 kPa) and upper limit (e.g., 950 kPa) of the target pressure range. This ensures that the pressure in the working fluid storage tank gradually approaches the target temperature, taking into account the time required for both pressurization and depressurization, and avoids frequent opening / closing of the pressure boosting or venting valves, which could cause system turbulence.

[0102] Based on the first, second, and third scenarios above, when the number of ablation needles connected in the pipeline is the same, the smaller the diameter of the ablation needle, the higher the pressure of the working fluid storage tank needs to be adjusted to ensure that the temperature of the cold working fluid at the tip of each ablation needle of different diameters meets the treatment temperature requirements.

[0103] In addition, when the number of ablation needles connected in the connecting pipeline is greater than or equal to 2, it is divided into the following four and five cases.

[0104] The fourth scenario is when the number of ablation needles connected in the pipeline is ≥2 and the diameter of the ablation needles is ≥d2. In this fourth scenario, the controller is configured to control the pressure boosting valve and / or venting valve on the working fluid storage tank, thereby adjusting the pressure of the working fluid storage tank to P1.

[0105] In the fourth case, the controller can use the same control method as in the first case to adjust the pressure of the working fluid storage tank to P1, which will not be elaborated further in this invention.

[0106] The fifth scenario is as follows: when the number of ablation needles connected in the pipeline is ≥2 and the diameter of the ablation needle is <d2, the controller controls the pressure boosting valve and / or venting valve on the working fluid storage tank to adjust the pressure of the working fluid storage tank to P2; where P1 < P2.

[0107] In the fifth case, the controller can use the same control method as in the second case to adjust the pressure of the working fluid storage tank to P2, which will not be elaborated further in this invention.

[0108] Based on the fourth and fifth scenarios above, when the number of ablation needles connected in the pipeline is the same, the smaller the diameter of the ablation needle, the higher the pressure of the working fluid storage tank needs to be adjusted to ensure that the temperature of the cold working fluid at the tip of each ablation needle of different diameters meets the treatment temperature requirements.

[0109] In addition, for the case where the number of ablation needles connected in the connecting pipeline is 0, i.e., the sixth case, the controller control method is as follows.

[0110] The controller is designed so that when the number of ablation needles connected in the pipeline is 0, the controller controls the pressure boosting valve and / or venting valve on the working fluid storage tank, thereby adjusting the pressure in the working fluid storage tank from P3 to P1-ΔP2, i.e., the target pressure is P1-ΔP2. Since the number of ablation needles connected in the pipeline is 0, meaning no ablation needles are connected, it indicates that the process is in preparation before the ablation operation. Therefore, in this case, the pressure in the working fluid storage tank can be adjusted to a smaller pressure range to avoid wasting the working fluid (liquid nitrogen).

[0111] Specifically, when the pressure in the working fluid storage tank is less than P1-2ΔP2, the pressure boosting valve is fully opened and the venting valve is fully closed; when the pressure in the working fluid storage tank is between P1-2ΔP2 and P1, the pressure boosting valve is gradually closed (at this time, the venting valve is fully closed); when the pressure in the working fluid storage tank is greater than P1, the venting valve is gradually opened; when the pressure in the working fluid storage tank is less than P1-ΔP3, the venting valve is fully closed, thereby adjusting the pressure in the working fluid storage tank to P1-2ΔP2. Where ΔP1 < ΔP2 < ΔP3 < P1 < P3.

[0112] Understandably, in the sixth case, the target pressure is P1-ΔP2 (600 kPa), P1-2ΔP2 is 550 kPa, and P1-ΔP3 is 570 kPa.

[0113] More specifically, in the sixth case, since the ablation needle is not connected in the connecting pipeline, it indicates that no ablation operation is performed at this time, but a pre-cooling operation is performed. Therefore, in the pre-cooling operation, it is necessary to control the target pressure of the working fluid storage tank to a small level, so as to reduce the consumption of liquid nitrogen.

[0114] In other words, in the sixth scenario, the target pressure of the working fluid storage tank is 600 kPa. When the pressure of the working fluid storage tank is less than 550 kPa, the controller controls the pressure boosting valve to fully open and the venting valve to fully close, allowing the working fluid storage tank to be pressurized to increase its pressure. When the pressure of the working fluid storage tank is between 550 kPa and 650 kPa, the controller controls the pressure boosting valve to gradually close. When the pressure of the working fluid storage tank is greater than 650 kPa, the controller controls the venting valve to gradually open, allowing the working fluid storage tank to be depressurized to reduce its pressure. When the pressure of the working fluid storage tank is less than 570 kPa, the controller controls the venting valve to fully close, thereby dynamically adjusting the pressure of the working fluid storage tank to 600 kPa.

[0115] During the above adjustment process, if the pressure in the working fluid storage tank is between 550 kPa and 650 kPa, it indicates that it is close to the target pressure. Therefore, the controller can gradually close the pressure boosting valve to gradually approach the target temperature. In other words, when adjusting the pressure of the working fluid storage tank, it is not directly compared with the target pressure, but rather compared with the lower limit (e.g., 550 kPa) and upper limit (e.g., 650 kPa) of the target pressure range. This ensures that the pressure in the working fluid storage tank gradually approaches the target temperature, taking into account the time required for both pressurization and depressurization, and avoids frequent opening / closing of the pressure boosting valve or venting valve, which could cause system turbulence.

[0116] In all the above scenarios, the controller uses PID control to regulate the opening and closing of the pressure boosting valve and the venting valve, allowing the pressure in the working fluid storage tank to gradually approach the target temperature. For example, controlling the gradual closing of the pressure boosting valve or the gradual opening of the venting valve can be achieved by adjusting the opening degree of the pressure boosting valve or the venting valve using PID control. For instance, the pressure boosting valve opening can be adjusted from 100% to 80%, then to 10%, and finally to 0%; or the venting valve opening can be adjusted from 0% to 20%, then to 70%, and finally to 100%.

[0117] In all the above-described cases, the working fluid storage tank is equipped with a pressure detection device, such as a pressure sensor, to detect its pressure. The pressure detection device is electrically connected to the controller, allowing it to provide feedback on the working fluid storage tank's pressure. Based on this pressure feedback, the controller implements the corresponding control strategies described above.

[0118] In a second aspect, the present invention provides a composite high and low temperature thermal ablation system, comprising a working fluid storage tank, a phase separation valve, a connecting pipeline, an ablation needle, and a controller. The connecting pipeline is used to connect to the working fluid storage tank, the phase separation valve, and the ablation needle, and the controller is connected to the working fluid storage tank, the phase separation valve, and the ablation needle respectively.

[0119] The working fluid storage tank of the present invention can be, for example, a cold tank for storing cold working fluids such as liquid nitrogen. Its structure can adopt various implementation methods in the prior art. Similarly, the phase separation valve, connecting pipeline and ablation needle can also adopt various implementation methods in the prior art.

[0120] The controller of this invention is configured to adjust the opening degree of the phase separation valve according to the number of ablation needles connected in the connecting pipeline and the diameter of the ablation needles connected in the connecting pipeline, so that the phase separation valve is maintained at a target temperature. The phase separation valve may, for example, be electrically connected to the controller, which is configured to send relevant commands to the phase separation valve to cause relevant components on the phase separation valve to perform corresponding actions, thereby adjusting the opening degree of the phase separation valve, for example, setting the opening degree of the phase separation valve to 100% or 0%.

[0121] The concept of this invention is to design different thresholds based on different combinations of ablation needle diameters and numbers, so as to achieve rapid cooling in the most liquid nitrogen-saving way regardless of how the ablation needles are combined.

[0122] Specifically, when the number of ablation needles connected in the connecting pipeline is 1, there are three situations.

[0123] The first scenario is: the number of ablation needles connected in the connecting pipeline is 1 and the diameter of the ablation needle is ≥d1, where d1 can be, for example, 2.6mm. The fact that the diameter of the ablation needle connected in the connecting pipeline is ≥d1 indicates that the diameter of the ablation needle connected in the connecting pipeline may be 2.6mm or larger.

[0124] In the first case described above, the controller is configured such that the opening of the phase separation valve is maintained at the target temperature T3 to T4.

[0125] Specifically, when the current temperature of the phase separation valve is ≥ T5, the controller adjusts the opening of the phase separation valve to 100%; when T4 ≤ the current temperature of the phase separation valve < T5, the controller adjusts the opening of the phase separation valve to K3; when T3 ≤ the current temperature of the phase separation valve < T4, the controller adjusts the opening of the phase separation valve to K4, where K4 > K3; when the current temperature of the phase separation valve is ≤ T3, the controller adjusts the opening of the phase separation valve to 0%, where T3 < T4 < T5.

[0126] K3 and K4 satisfy the following expressions respectively:

[0127]

[0128] Where k is a constant, and its value ranges from 1 to k to 1.2.

[0129] The value of k is an empirical constant summarized and verified based on experimental results, and its value is related to the pressure of the working fluid storage tank and the number of ablation needles connected in the pipeline. In the first case, the pressure of the working fluid storage tank is the target pressure P1 (650 kPa), and the number of ablation needles connected in the pipeline is 1. Therefore, the controller adjustment needs to be more significant so that the phase separation valve can be adjusted to the target temperature more quickly, thus bringing the value of k closer to its maximum value. Therefore, in the first case, the value of k can be 1.15.

[0130] More specifically, T3 is -5℃, T4 is 0℃, and T5 is 10℃. Understandably, in the first case described above, the controller is configured such that the opening of the phase separation valve is maintained at the target temperature of -5℃ to 0℃.

[0131] Specifically, when T3 is -5℃, the flow rate of the phase separation valve is 15L / min-18L / min; when T4 is 0℃, the flow rate of the phase separation valve is 10L / min-14L / min; and when T5 is 10℃, the flow rate of the phase separation valve is 8L / min-10L / min, which ensures that the consumption of liquid nitrogen is relatively low.

[0132] Therefore, the controller adjusts the opening degree of the phase separation valve as follows:

[0133] When the current temperature of the phase separation valve is ≥10℃, the controller adjusts the opening of the phase separation valve to 100%; when 0℃≤current temperature of the phase separation valve<10℃, the controller adjusts the opening of the phase separation valve to K3; when -5℃≤current temperature of the phase separation valve<0℃, the controller adjusts the opening of the phase separation valve to K4, where K4>K3; when the current temperature of the phase separation valve is ≤-5℃, the controller adjusts the opening of the phase separation valve to 0%.

[0134] K3 satisfies the following expression:

[0135]

[0136] K4 satisfies the following expressions:

[0137]

[0138] The second scenario is: the number of ablation needles connected in the connecting tubing is 1, and the diameter of the ablation needle is between d2 and d1. Here, d2 can be, for example, 2mm, and the diameter of the ablation needle connected in the connecting tubing being between d2 and d1 indicates that the diameter of the ablation needle connected in the connecting tubing may be 2mm or 2.5mm, etc.

[0139] In the second scenario described above, the controller adjusts the opening of the phase separation valve to maintain it at a target temperature, which is T3 to T4. Understandably, in this second scenario, the controller is configured to adjust the opening of the phase separation valve to maintain it at a target temperature of -5°C to 0°C.

[0140] In the second case, the controller can use the same control method as in the first case to adjust the opening of the phase separation valve to keep the phase separation valve at the target temperature, which is T3 to T4. This invention will not elaborate further on this.

[0141] The third scenario is: the number of ablation needles connected in the connecting tubing is 1, and the diameter of the ablation needle is < d2. Here, d2 can be, for example, 2 mm, and the diameter of the ablation needle connected in the connecting tubing < d2 indicates that the diameter of the ablation needle connected in the connecting tubing may be 1.7 mm.

[0142] In the third case, the controller is configured to adjust the opening of the phase separation valve to maintain the phase separation valve at a target temperature, which is T1 to T2.

[0143] Specifically, when the current temperature of the phase separation valve is ≥ T2, the controller adjusts the opening of the phase separation valve to 100%; when T1 ≤ the current temperature of the phase separation valve < T2, the controller adjusts the opening of the phase separation valve to K1; when the current temperature of the phase separation valve < T1, the controller adjusts the opening of the phase separation valve to 0%, where T1 < T2; and K1 satisfies the following expression:

[0144]

[0145] k is a constant, and its value range is 1≤k≤1.2.

[0146] The value of k is an empirical constant summarized and verified based on experimental results, and its value is related to the pressure of the working fluid storage tank and the number of ablation needles connected in the connecting pipeline. In the third case, the pressure of the working fluid storage tank is the target pressure P3 (1000 kPa), and the number of ablation needles connected in the connecting pipeline is 1. Therefore, the degree of controller adjustment can be slightly smaller than in the first case. Thus, in the third case, the value of k can be 1.12.

[0147] More specifically, T1 can be, for example, -15°C, and T2 can be, for example, -10°C. Understandably, in the third case described above, the controller is configured such that the opening of the phase separation valve is maintained at the target temperature of -15°C to -10°C.

[0148] Therefore, the controller adjusts the opening degree of the phase separation valve as follows:

[0149] When the current temperature of the phase separation valve is ≥ -10℃, the controller adjusts the opening of the phase separation valve to 100%; when -15℃ ≤ the current temperature of the phase separation valve < -10℃, the controller adjusts the opening of the phase separation valve to K1; when the current temperature of the phase separation valve is < -15℃, the controller adjusts the opening of the phase separation valve to 0%, where T1 < T2; and K1 satisfies the following expression:

[0150]

[0151] In addition, when the number of ablation needles connected in the connecting pipeline is greater than or equal to 2, it is divided into the following four and five cases.

[0152] The fourth scenario is when the number of ablation needles connected in the pipeline is ≥2 and the diameter of the ablation needles is ≥d2. In this fourth scenario, the controller adjusts the opening of the phase separation valve to maintain the phase separation valve at a target temperature, which is T3 to T4. Understandably, in the second scenario, the controller is configured to adjust the opening of the phase separation valve to maintain it at a target temperature of -5℃ to 0℃.

[0153] In the fourth case, the controller can use the same control method as in the first case to adjust the opening of the phase separation valve to keep the phase separation valve at the target temperature, which is T3 to T4. This invention will not elaborate further on this.

[0154] Furthermore, the fifth case is: when the number of ablation needles connected in the connecting pipeline is ≥2 and the diameter of the ablation needle is <d2.

[0155] In the fifth scenario, the controller adjusts the opening of the phase separation valve to maintain it at a target temperature, which is T2 to T3. Understandably, in this fifth scenario, the controller is configured to adjust the opening of the phase separation valve to maintain it at a target temperature of -10°C to -5°C.

[0156] For example, in the fifth case, when the current temperature of the phase separation valve is ≥ T3, the controller adjusts the opening of the phase separation valve to 100%; when T2 ≤ the current temperature of the phase separation valve < T3, the controller adjusts the opening of the phase separation valve to K2; when the current temperature of the phase separation valve < T2, the controller adjusts the opening of the phase separation valve to 0%, where T2 < T3; and K2 satisfies the following expression:

[0157]

[0158] k is a constant, and its value range is 1≤k≤1.2.

[0159] The value of k is an empirical constant summarized and verified based on experimental results, and its value is related to the pressure of the working fluid storage tank and the number of ablation needles connected in the connecting pipeline. In the fifth case, the pressure of the working fluid storage tank is the target pressure P2 (850 kPa), and the number of ablation needles connected in the connecting pipeline is 2. Therefore, the degree of controller adjustment can be smaller than in the first case. Thus, in the fifth case, the value of k can be 1.05.

[0160] Therefore, the controller adjusts the opening degree of the phase separation valve as follows:

[0161] When the current temperature of the phase separation valve is ≥ -5℃, the controller adjusts the opening of the phase separation valve to 100%; when -10℃ ≤ the current temperature of the phase separation valve < -5℃, the controller adjusts the opening of the phase separation valve to K2; when the current temperature of the phase separation valve is < -10℃, the controller adjusts the opening of the phase separation valve to 0%, where K2 satisfies the following expression:

[0162]

[0163] Furthermore, in the case where the number of ablation needles connected in the connecting pipeline is 0, i.e., the sixth case, the controller is configured such that when the number of ablation needles connected in the connecting pipeline is 0, the controller adjusts the opening of the phase separation valve to maintain the phase separation valve at the target temperature, which is T3 to T4.

[0164] In the sixth scenario, the controller can employ the same control method as in the first scenario to adjust the opening of the phase separation valve to maintain it at the target temperature, which is T3 to T4. This will not be elaborated further in this invention. Understandably, in the sixth scenario, the controller is configured to adjust the opening of the phase separation valve to maintain it at the target temperature of -5°C to 0°C.

[0165] It should be noted that the current temperature of the phase separation valve refers to the temperature obtained at the temperature measuring point downstream of the phase separation valve, which is generally the temperature of the gaseous working fluid separated by the phase separation valve (or may also include a small amount of liquid working fluid). Therefore, if the current temperature of the phase separation valve is high (e.g., greater than 10°C), it indicates that there is a large amount of gas in the working fluid, so it is necessary to increase the opening of the phase separation valve to increase the discharge gas velocity.

[0166] In all the above scenarios, the value of k is related to the pressure of the working fluid storage tank and the number of ablation needles connected in the connecting pipeline. Specifically, the lower the pressure of the working fluid storage tank, the larger the value of k; and the fewer the number of ablation needles connected in the connecting pipeline, the larger the value of k. A larger value of k indicates a greater degree of adjustment of the phase separation valve opening by the controller, thus enabling more agile feedback adjustment based on the phase separation temperature.

[0167] In all the above-described cases, a temperature detection device, such as a temperature sensor or thermocouple, is installed on the phase separation valve (or in its downstream pipeline) to detect the temperature of the phase separation valve. The temperature detection device is electrically connected to the controller, allowing it to provide feedback on the temperature of the working fluid storage tank. Based on the temperature feedback from the temperature detection device, the controller implements the corresponding control strategy described above.

[0168] Furthermore, the controller of the present invention can also be configured to adjust the pressure of the working fluid storage tank and the opening of the phase separation valve according to the number of ablation needles connected in the connecting pipeline and the diameter of the ablation needles connected in the connecting pipeline, so that the pressure of the working fluid storage tank is maintained near the target pressure and the phase separation valve is maintained at the target temperature.

[0169] In a third aspect, the present invention provides a control method for a composite high-low temperature thermal ablation system. The control method is applied to the aforementioned composite high-low temperature thermal ablation system and includes the following steps:

[0170] Step 100: Determine if the number of ablation needles connected in the connecting pipeline is 0. If yes, proceed to step 200; otherwise, proceed to step 300.

[0171] Specifically, feedback can be provided through the connection positioning device on the ablation needle. For example, when the connecting tube is connected to the corresponding ablation needle, it indicates that the two are properly engaged, and the connection positioning device will send a signal to the controller that the ablation needle is connected, indicating that the ablation needle is connected in the connecting tube; otherwise, it indicates that the ablation needle is not connected in the connecting tube.

[0172] Step 200: For the case where the number of ablation needles connected in the connecting pipeline is 0 (i.e., the sixth case mentioned above), adjust the pressure of the working fluid storage tank from P3 to P1-ΔP2, and maintain the current temperature of the phase separation valve between T3 and T4.

[0173] In this case, adjusting the pressure of the working fluid storage tank from P3 to P1-ΔP2 and maintaining the current temperature of the phase separation valve between T3 and T4 can be achieved using the control method described in the sixth case above.

[0174] Step 300: If the number of ablation needles connected in the connecting tubing is not zero, further judgment is required. Specifically, determine whether the number of ablation needles connected in the connecting tubing is 1. If yes, proceed to step 400; otherwise, proceed to step 500.

[0175] Step 400: If the number of ablation needles connected in the connecting pipeline is 1, further judgment is required. That is, determine whether the diameter of the ablation needle connected in the connecting pipeline is ≥d1. If the diameter of the ablation needle connected in the connecting pipeline is ≥d1 (i.e., corresponding to the first case above), then adjust the pressure of the working fluid storage tank to P1 and maintain the current temperature of the phase separation valve between T3 and T4 (i.e., step 403); otherwise, proceed to step 401, that is, further judgment is required.

[0176] In this case, adjusting the pressure of the working fluid storage tank to P1 and maintaining the current temperature of the phase separation valve between T3 and T4 can be achieved using the control method described in the first case above.

[0177] Step 401: Determine whether the diameter of the ablation needle connected in the connecting pipeline is between d2 and d1. If the diameter of the ablation needle connected in the connecting pipeline is between d2 and d1 (i.e., corresponding to the second case above), then adjust the pressure of the working fluid storage tank to P2 and maintain the current temperature of the phase separation valve between T3 and T4 (i.e., step 404); otherwise, proceed to step 402.

[0178] In this case, adjusting the pressure of the working fluid storage tank to P2 and maintaining the current temperature of the phase separation valve between T3 and T4 can be achieved using the control method described in the second scenario above.

[0179] Step 402: Determine if the diameter of the ablation needle connected in the connecting pipeline is less than d2. If the diameter of the ablation needle connected in the connecting pipeline is less than d2 (i.e., corresponding to the third case described above), then adjust the pressure of the working fluid storage tank to P3 and maintain the current temperature of the phase separation valve between T1 and T2.

[0180] In this case, adjusting the pressure of the working fluid storage tank to P3 and maintaining the current temperature of the phase separation valve between T1 and T2 (i.e., step 405) can be achieved using the control method described in the third case above.

[0181] 500: If the number of ablation needles connected in the connecting pipeline is ≥2, further judgment is required. That is, determine whether the diameter of the ablation needles connected in the connecting pipeline is ≥d2. If the diameter of the ablation needles connected in the connecting pipeline is ≥d2 (i.e., the fourth case mentioned above), then adjust the pressure of the working fluid storage tank to P1 and maintain the current temperature of the phase separation valve between T3 and T4 (i.e., step 403); otherwise, proceed to step 501.

[0182] In this case, adjusting the pressure of the working fluid storage tank to P1 and maintaining the current temperature of the phase separation valve between T3 and T4 can be achieved using the control method described in the fourth case above.

[0183] 501: Determine if the diameter of the ablation needle connected in the connecting pipeline is less than d2. If the diameter of the ablation needle connected in the connecting pipeline is less than d2 (i.e., corresponding to the fifth case described above), then adjust the pressure of the working fluid storage tank to P2 and maintain the current temperature of the phase separation valve between T2 and T3 (i.e., step 502). Wherein, ΔP2 < P1 < P2 < P3; T1 < T2 < T3 < T4.

[0184] In this case, adjusting the pressure of the working fluid storage tank to P2 and maintaining the current temperature of the phase separation valve between T2 and T3 can be achieved using the control method described in the fifth case above.

[0185] This method can be terminated once the pre-cooling or ablation operation is completed.

[0186] Example 1

[0187] The ablation needle is not connected in the pipeline.

[0188] The target pressure of the working fluid storage tank is 600 kPa. When the pressure of the working fluid storage tank is less than 550 kPa, the controller controls the pressure boosting valve to fully open and the venting valve to fully close. When the pressure of the working fluid storage tank is between 550 kPa and 650 kPa, the controller controls the pressure boosting valve to gradually close. When the pressure of the working fluid storage tank is greater than 650 kPa, the controller controls the venting valve to gradually open. When the pressure of the working fluid storage tank is less than 650 kPa, the controller controls the venting valve to fully close, thereby dynamically adjusting the pressure of the working fluid storage tank to 570 kPa.

[0189] During this process, the liquid nitrogen consumption is approximately 3%, and the pre-cooling operation of the composite high-low temperature thermal ablation system lasts for 6 minutes (i.e., the time it takes for the composite high-low temperature thermal ablation system to cool down to the required temperature).

[0190] Therefore, when the ablation needle is not connected in the connecting pipeline, that is, during the precooling process of the system, the pressure of the working fluid storage tank is controlled so that the consumption of liquid nitrogen meets the requirement of less than 8%, and the precooling time meets the requirement of no more than 8 minutes.

[0191] Example 2

[0192] The number of ablation needles connected in the connecting pipeline is 1.

[0193] The ablation needle has a diameter of 3mm. The target pressure of the working fluid storage tank is 650kPa. When the pressure of the working fluid storage tank is less than 600kPa, the controller controls the pressure boosting valve to fully open and the venting valve to fully close. When the pressure of the working fluid storage tank is between 600kPa and 700kPa, the controller controls the pressure boosting valve to gradually close. When the pressure of the working fluid storage tank is greater than 700kPa, the controller controls the venting valve to gradually open. When the pressure of the working fluid storage tank is less than 620Pa, the controller controls the venting valve to fully close, thereby dynamically adjusting the pressure of the working fluid storage tank to 650kPa.

[0194] When using this ablation needle for ablation, the liquid nitrogen consumption is approximately 13%, the ice ball size is approximately 50mm (minor axis) × 70mm (major axis), and the ablation operation lasts for 20 minutes. It should be noted that the above ice ball dimensions are measured in a gelatin environment at 37°C.

[0195] The ablation needle has a diameter of 2.6 mm. The target pressure of the working fluid storage tank is 850 kPa. When the pressure of the working fluid storage tank is less than 800 kPa, the controller controls the pressure boosting valve to fully open and the venting valve to fully close. When the pressure of the working fluid storage tank is between 800 kPa and 900 kPa, the controller controls the pressure boosting valve to gradually close. When the pressure of the working fluid storage tank is greater than 800 kPa, the controller controls the venting valve to gradually open. When the pressure of the working fluid storage tank is less than 820 kPa, the controller controls the venting valve to fully close, thereby dynamically adjusting the pressure of the working fluid storage tank to 850 kPa.

[0196] When using this ablation needle for ablation, the liquid nitrogen consumption is approximately 15%, the ice ball size is approximately 43mm (minor axis) × 52mm (major axis), and the ablation operation lasts for 20 minutes. It should be noted that the above ice ball dimensions are measured in a gelatin environment at 37°C.

[0197] The ablation needle has a diameter of 1.7 mm. The target pressure of the working fluid storage tank is 1000 kPa. When the pressure of the working fluid storage tank is less than 900 kPa, the controller controls the pressure boosting valve to fully open and the venting valve to fully close. When the pressure of the working fluid storage tank is between 850 kPa and 950 kPa, the controller controls the pressure boosting valve to gradually close. When the pressure of the working fluid storage tank is greater than 950 kPa, the controller controls the venting valve to gradually open. When the pressure of the working fluid storage tank is less than 920 kPa, the controller controls the venting valve to fully close, thereby dynamically adjusting the pressure of the working fluid storage tank to 1000 kPa.

[0198] When using this ablation needle for ablation, the liquid nitrogen consumption is approximately 17%, the ice ball size is approximately 28mm (minor axis) × 32mm (major axis), and the ablation operation lasts for 20 minutes. It should be noted that the above ice ball dimensions are measured in a gelatin environment at 37°C. Therefore, when connecting the ablation needle in the tubing, the pressure of the working fluid storage tank should be controlled to ensure that the liquid nitrogen consumption (total) is less than 20% (for the minimum diameter of the ablation needle connected in the tubing).

[0199] Example 3

[0200] The number of ablation needles connected in the connecting pipeline is 2.

[0201] The ablation needles have diameters of 3mm and 2.6mm. The target pressure of the working fluid storage tank is 650kPa. When the pressure of the working fluid storage tank is less than 600kPa, the controller controls the pressure boosting valve to fully open and the venting valve to fully close; when the pressure of the working fluid storage tank is between 600kPa and 700kPa, the controller controls the pressure boosting valve to gradually close; when the pressure of the working fluid storage tank is greater than 700kPa, the controller controls the venting valve to gradually open; when the pressure of the working fluid storage tank is less than 620Pa, the controller controls the venting valve to fully close, thereby dynamically regulating the pressure of the working fluid storage tank to 650kPa.

[0202] When using this ablation needle for ablation, the liquid nitrogen consumption is approximately 28%, and the ablation operation lasts for 20 minutes.

[0203] The ablation needles have diameters of 1.7 mm and 1.7 mm. The target pressure of the working fluid storage tank is 850 kPa. When the pressure of the working fluid storage tank is less than 800 kPa, the controller controls the pressure boosting valve to fully open and the venting valve to fully close; when the pressure of the working fluid storage tank is between 800 kPa and 900 kPa, the controller controls the pressure boosting valve to gradually close; when the pressure of the working fluid storage tank is greater than 800 kPa, the controller controls the venting valve to gradually open; when the pressure of the working fluid storage tank is less than 820 kPa, the controller controls the venting valve to fully close, thereby dynamically adjusting the pressure of the working fluid storage tank to 850 kPa.

[0204] When using this ablation needle for ablation, the liquid nitrogen consumption is approximately 32%, the ice ball size is approximately 30mm (minor axis 1) × 37mm (minor axis 2) × 46mm (major axis) (the distance between the two ablation needles is 10mm), and the ablation operation lasts for 20 minutes. It should be noted that the above ice ball dimensions are measured in a gelatin environment at 37°C.

[0205] Therefore, when connecting the ablation needle in the connecting pipeline, the pressure of the working fluid storage tank is controlled so that the consumption (total) of liquid nitrogen basically meets the requirement of less than 30% (for the minimum diameter of the ablation needle connected in the connecting pipeline).

[0206] Although the invention has been described with reference to preferred embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. The invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A combined high and low temperature cold thermal ablation system, characterized by, The system comprises a working medium storage tank, a phase separation valve, a connecting pipeline, an ablation needle and a controller, the connecting pipeline is used for connecting the working medium storage tank, the phase separation valve and the ablation needle, and the controller is connected with the working medium storage tank, the phase separation valve and the ablation needle respectively; The controller is configured to execute the following steps: S100: judging whether the number of the ablation needles connected in the connecting pipeline is 0, if yes, executing step S200, if not, executing step S300; S200: Adjust the pressure of the working fluid storage tank from P 3 to P 1-Δ P 2, and maintain the phase separation valve at the target temperature T 3 to T 4; S300: judging whether the number of the ablation needles connected in the connecting pipeline is 1, if yes, executing step S400, if not, executing step S500; S300: judging whether the number of the ablation needles connected in the connecting pipeline is 1, if yes, executing step S400, if not, executing step S500; S400: Determine whether the diameter of the ablation needle connected in the connecting pipeline is ≥ d 1, if yes, adjust the working medium storage tank pressure to P 1, and keep the phase separation valve at the target temperature T 3 to T 4, if no, execute step S401; S401: Determine whether the diameter of the ablation needle connected in the connecting pipeline is between d 2 and d 1, if yes, adjust the working medium storage tank pressure to P 2, and keep the phase separation valve at the target temperature T 3 to T 4, if not, execute step S402; S402: judge whether the diameter of the ablation needle connected in the connecting pipeline is < 0.5 mm d 2, if yes, adjust the working medium storage tank pressure to 20 MPa P 3, and keep the phase separation valve at the target temperature T 1 to T 2; S500: Determine whether the diameter of the ablation needle connected in the connecting pipeline is ≥ d 2, if yes, adjust the working medium storage tank pressure to P 1, and keep the phase separation valve at the target temperature T 3 to T 4, if no, execute step S501; S501: Determine if the diameter of the ablation needle connected in the connecting line is < 1.5 mm d 2, if yes, adjust the working medium storage tank pressure to P 2, and keep the phase separation valve at the target temperature T 2 to T 3; where Δ P 2 < Δ < 4 P 1 < Δ < 3 P 2 < Δ < 4 P 3 T 1 < Δ < 3 T 2 < Δ < 4 T 3 < Δ < 5 T 4 2. The combined cryo- and thermal-ablation system of claim 1, wherein, In step S400 or step S500, the working fluid storage tank pressure is adjusted to P 1 when: if the pressure of the working fluid storage tank is less than P 1-Δ P 2, then the controller fully opens a pressure increasing valve on the working fluid storage tank and fully closes a pressure decreasing valve on the working fluid storage tank; if the pressure in the working fluid storage tank is between P 1-Δ P 2 and P 1+Δ P 2, then the controller gradually closes a pressure increasing valve on the working fluid storage tank; If the pressure of the working fluid storage tank is greater than P 1+Δ P 2, the controller gradually opens a gas release valve on the working fluid storage tank. if the pressure of the working fluid storage tank is less than P 1 - Δ P 1, then the controller fully closes a bleed valve on the working fluid storage tank, such that the controller regulates the pressure of the working fluid storage tank to P 1 ; wherein, P 1 is the pressure of the working fluid storage tank, Δ P 1, Δ P 2 are the pressure change amounts of the working fluid storage tank, respectively, Δ P 1 < Δ P 2.

3. The combined high and low temperature cold thermal ablation system of claim 1 or 2, wherein, In step S200, step S400, step S401, or step S500, the target temperature of the phase separation valve is T 3 to T 4: If the current temperature of the phase separation valve is ≥ T At time 5, the controller adjusts the opening of the phase separation valve to 100%. If T 4 < the current temperature of the phase separation valve < 5, T then the controller adjusts the opening of the phase separation valve to K 3. If T 3 < the current temperature of the phase separation valve < 4 T 4, then the controller adjusts the opening of the phase separation valve to K 4, where K 4 > 3 K 3; if the current temperature of the phase separation valve < 3, then the controller adjusts the opening of the phase separation valve to 0%, wherein, T 3 T 3 < 5 T 4 < 5 T 5; wherein k is a constant having a value in the range 1 k ≤ 1.

2.

4. The combined high and low temperature cold thermal ablation system of claim 3, wherein, K 3 and K 4 satisfy the following expressions, respectively:

5. The combined cryo- and thermal-ablation system of claim 1 or 2, wherein, In step S401, the working fluid storage tank pressure is adjusted to P 2 when: if the pressure of the working fluid storage tank is less than P 2-Δ P 2, the controller fully opens a pressure increasing valve on the working fluid storage tank and fully closes a pressure decreasing valve on the working fluid storage tank; if the pressure of the working fluid storage tank is between P 2-Δ P 2 and P 2+Δ P 2, the controller gradually closes a pressure increasing valve on the working fluid storage tank; if the pressure of the working fluid storage tank is greater than P 2-Δ P 2, then the controller gradually opens a gas bleed valve on the working fluid storage tank; if the pressure of the working fluid storage tank is less than P 2-Δ P 1, then the controller fully closes a bleed valve on the working fluid storage tank, such that the controller regulates the pressure of the working fluid storage tank to P 2-Δ. wherein Δ P 1 P 2 P 1 P 2 6. The combined cryo- and hyperthermia ablation system of claim 5, wherein, In step S501, the phase separation valve is maintained at the target temperature T 2 to T 3: If the current temperature of the phase separation valve is ≥ T 3, then the controller adjusts the opening of the phase separation valve to 100%. If T 2 < the current temperature of the phase separation valve < 3, T then the controller adjusts the opening of the phase separation valve to K 2. if the current temperature of the phase separation valve < 0°C, then the controller adjusts the opening of the phase separation valve to 0%, wherein, T 2 is greater than 0°C and less than 30°C, then the controller adjusts the opening of the phase separation valve to 100%. T 2 is greater than 30°C, then the controller adjusts the opening of the phase separation valve to 0%. T 3. The method of claim 1, wherein the controller adjusts the opening of the phase separation valve wherein K 2 satisfies the following expression: k is a constant, which has a value range of 1≤ k ≤1.

2.

7. The combined cryo- and thermal-ablation system of claim 1 or 2, wherein, In step S402, the working fluid storage tank pressure is adjusted to P 3 hours: if the pressure of the working fluid storage tank is less than P 3-2Δ P 2, the controller fully opens a pressure increasing valve on the working fluid storage tank and fully closes a pressure decreasing valve on the working fluid storage tank; if the pressure in the working fluid storage tank is between P 3-2Δ P 2 and P 3-Δ P 2, then the controller gradually closes a pressure increasing valve on the working fluid storage tank; if the pressure of the working fluid storage tank is greater than P 3-Δ P 2, then the controller gradually opens a gas bleed valve on the working fluid storage tank; if the pressure of the working fluid storage tank is less than P 3-Δ P 3, then the controller fully closes a bleed valve on the working fluid storage tank; whereby the controller regulates the pressure of the working fluid storage tank to P 3; wherein, P 1, P 2, P 3 are pressure of the working fluid storage tank respectively, P 1 P 2 P 3; Δ P 1, Δ P 2, Δ P 3 are pressure change amount of the working fluid storage tank respectively, Δ P 1 P 2 P 3.

8. The combined high and low temperature cold thermal ablation system of claim 7, wherein, In step S402, the phase separation valve is maintained at the target temperature T 1 to T 2: If the current temperature of the phase separation valve is ≥ T 2, then the controller adjusts the opening of the phase separation valve to 100%. If T 1 < the current temperature of the phase separation valve < 2, T then the controller adjusts the opening of the phase separation valve to K 1. If the current temperature of the phase separation valve is < T When 1 is reached, the controller adjusts the opening of the phase separation valve to 0%, wherein, T 1 < T 2; wherein K 1 satisfies the following expression: k is constant and has a value in the range 1≤ k ≤1.

2.

9. The combined cryo- and thermal-ablation system of claim 1 or 2, wherein, In step S200, the pressure of the working fluid storage tank is adjusted from P 3 to P 1-Δ P 2 if the pressure of the working fluid storage tank is less than P 1-2Δ P 2, the controller fully opens a pressure increasing valve on the working fluid storage tank and fully closes a pressure decreasing valve on the working fluid storage tank; if the pressure in the working fluid reservoir is between P 1-2Δ P 2 and P 1, the controller gradually closes a pressure increasing valve on the working fluid reservoir; If the pressure of the working fluid storage tank is greater than P 1, the controller gradually opens a gas release valve on the working fluid storage tank. if the pressure of the working fluid storage tank is less than P 1 - Δ P 3, then the controller fully closes a bleed valve on the working fluid storage tank, such that the controller regulates the pressure of the working fluid storage tank to P 1 - Δ P 2; wherein, P 2, P 3 are the pressure of the working fluid storage tank, Δ P 3 is the pressure change amount of the working fluid storage tank, Δ P 1 < Δ P 2 < Δ P 3 < Δ P 1 < Δ P 3.

10. The combined cryo- and thermal-ablation system of claim 1 or 2, wherein, P 1 is 650 kPa, P 2 is 850 kPa, P 3 is 1000 kPa, Δ P 1 is 5 kPa ~ 30 kPa, Δ P 2 is 10 kPa ~ 50 kPa, Δ P 3 is 30 kPa ~ 80 kPa.

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