Ultrasonic ablation system and ablation method

Abstract

The invention discloses an ultrasonic ablation system and method, and relates to the technical field of interventional medical instruments.The ultrasonic ablation system comprises a first driving unit and a second driving unit, the first driving unit is connected with a first pipeline, and the first pipeline communicates with a water return channel; the second driving unit is connected with the second pipeline; the second pipeline is communicated with the water inlet channel; the ablation host, the first driving unit and the second driving unit are electrically connected with the ablation host, the first driving unit and the second driving unit are independently adjusted through the ablation host, net flow difference generated between cooling liquid entering and flowing out of the balloon is controlled, the balloon is expanded and deformed, the net flow difference is adjusted, and the outer diameter of the balloon is adjusted to the target diameter. According to the system, the mechanical injury risk of vascular interlayer and rupture caused by excessive expansion of the balloon is fundamentally eliminated, and the safety of a vascular interventional operation is improved.

Description

Technical Field

[0001] This invention relates to the field of interventional medical device technology, specifically to an ultrasonic ablation system and ablation method, which is an ultrasonic ablation device and its intelligent method that can achieve low pressure, adaptive diameter change and efficient cooling. Background Technology

[0002] Ultrasonic ablation has been widely used in interventional procedures such as hypertension treatment due to its advantages of minimal damage to the vascular endothelium and high safety. Its core technology involves delivering an ultrasound transducer to the target blood vessel via a catheter, using a balloon to centrally position the transducer, and simultaneously protecting the blood vessel wall from overheating damage through circulating cooling fluid within the balloon.

[0003] Currently, there are several main technical solutions for achieving balloon diameter variation to accommodate blood vessels of different sizes, but all of them have significant drawbacks: Category 1: Separate cooling and positioning design (e.g., CN117797421A). This design uses an independent cooling balloon to encapsulate the transducer, plus a mechanically variable outer diameter component (such as a shape memory metal basket) to achieve vessel wall contact and centering. Its fundamental drawback is that the cooling balloon does not directly contact the vessel wall, resulting in the cooling medium not effectively cooling the vessel intima, posing a risk of thermal damage; simultaneously, the additional mechanical components complicate the catheter structure and reduce reliability.

[0004] The second type is the multi-balloon discrete switching design (such as CN120938546A). This solution achieves limited size selection by integrating two or more fixed-size balloons and a complex internal flow channel switching mechanism. Essentially, it is still a mechanical integration of multiple catheters, unable to achieve continuous stepless diameter change, and the internal switching valve is prone to failure in confined spaces, resulting in a complex structure and poor reliability.

[0005] The third type: Single-pump high-pressure differential passive diameter reduction design (e.g., CN120732499A). This scheme represents the current mainstream technical approach, which involves designing the water injection channel to have a larger cross-sectional area than the return water channel, utilizing the resulting positive pressure difference to inflate the balloon. This scheme suffers from three interrelated fundamental contradictions: 1. High pressure risk: In order to achieve the expansion size required in clinical practice (such as a diameter of 4-12 mm), the pressure inside the cyst needs to be maintained as high as 2-6 standard atmospheres (atm). This high pressure acts directly on the blood vessel wall, which can easily cause vascular dissection, intimal tear or even vascular rupture, raising serious safety concerns.

[0006] 2. The contradiction between cooling and diameter change: In order to form and maintain a high pressure difference, the system must limit the return water flow rate, which inevitably leads to slow coolant circulation, low heat exchange efficiency, and inability to effectively remove the heat generated by the transducer, thus exacerbating the risk of thermal damage to the blood vessel wall.

[0007] 3. Passive and unsafe control: Its expansion process is a passive result of pressure difference, lacking active and precise size control capabilities, and the system does not have an effective pressure limiting mechanism, which poses a risk that the balloon may over-inflate due to pressure accumulation and eventually rupture.

[0008] Therefore, there is an urgent need in this field for a new type of ultrasonic ablation system that can fundamentally solve the above contradictions and achieve low-pressure, high-efficiency, and intelligent integrated control. Summary of the Invention

[0009] To solve the above-mentioned technical problems, the present invention provides an ultrasonic ablation system, including an interventional catheter unit, a balloon and an ultrasonic transducer located inside the balloon at its distal end, the interventional catheter unit also having independent water inlet channel and water return channel, the water inlet channel and water return channel respectively communicating with the inner cavity of the balloon, the balloon being made of a compliant material; It also includes a first drive unit and a second drive unit. The first drive unit is connected to a first pipeline, which is connected to a return water channel. The second drive unit is connected to a second pipeline, which is connected to a water inlet channel. The ablation host, the first drive unit and the second drive unit are both electrically connected to the ablation host. The ablation host independently adjusts the first drive unit and the second drive unit to control the net flow difference between the coolant entering and leaving the balloon, causing the balloon to expand and deform. Adjusting the net flow difference adjusts the outer diameter of the balloon to the target diameter.

[0010] Preferably, the first drive unit is a water pump, the inlet of which is connected to the cooling water outlet through a first pipeline, and the outlet of which is connected to the cooling unit through a first pipeline.

[0011] Preferably, the second drive unit is a water inlet pump, the inlet of which is connected to the cooling unit through a second pipeline, and the outlet of which is connected to the cooling water inlet through a second pipeline.

[0012] Preferably, it also includes a cooling unit for storing coolant. The coolant enters the balloon through the water inlet channel of the interventional catheter unit via the second pipeline and the second drive unit, and then flows back to the cooling unit through the water return channel into the first pipeline and the first drive unit.

[0013] Preferably, a detection unit is also provided, including a pressure sensor located inside the balloon and / or near the end of the return water channel, for real-time monitoring of the pressure inside the balloon.

[0014] Preferably, the detection unit further includes a temperature sensor for monitoring the coolant temperature, and the signals monitored by the pressure sensor and the temperature sensor are fed back to the controller in real time. The controller is located inside the ablation host.

[0015] Preferably, the interventional catheter unit includes a multi-lumen tube, with an inlet water channel and an outlet water channel axially arranged inside the multi-lumen tube. An inner tube is coaxially arranged inside the multi-lumen tube, with the distal end of the inner tube extending to the outside of the multi-lumen tube. The multi-lumen tube has an inner lumen corresponding to the inner tube, and an ultrasonic transducer is fixed on the inner tube.

[0016] A method for ultrasonic ablation, the specific steps of which are as follows: S1. Determine the target diameter of the balloon based on the target blood vessel diameter; S2. Match the target diameter of the spherical bag with the mapping table to determine the target net flow difference, the first flow rate, and the second flow rate; S3. Start the first drive unit to run at the first flow rate, the balloon expands to the nominal diameter, the coolant forms a cooling cycle inside the balloon, and the detection unit monitors the internal pressure of the balloon in real time. S4. Start the second drive unit to operate at the second flow rate, and generate expansion pressure by accumulating in the balloon through the target net flow rate difference, driving the balloon to expand to the target diameter; S5. In real time, determine whether the actual pressure inside the balloon is less than the preset P_max. If yes, proceed to the next step; otherwise, control the first drive unit and / or the second drive unit to decelerate and depressurize the balloon. S6. Keep the balloon stable at the target diameter and perform ultrasonic ablation.

[0017] Preferably, the stable actual pressure inside the balloon is less than 1 atm.

[0018] Preferably, the first flow rate is the base flow rate, which is a constant cooling flow rate, so that the coolant forms a basic cooling cycle within the bladder; The second flow rate is the sum of the difference between the first flow rate and the net flow rate.

[0019] The technical effects and advantages of this invention are as follows: 1. This system achieves excellent thermal management by precisely controlling the flow difference to ensure continuous and rapid cooling of the balloon. It can also reduce the working pressure of the balloon from the high pressure range of 2-6 atm in existing technologies to an extremely low level of less than 1 atm. The low pressure makes the balloon more flexible, which can better adapt to and conform to irregular blood vessel walls, eliminate gaps, improve the efficiency of ultrasound energy transmission, and achieve more uniform and effective ablation.

[0020] 2. It can also fundamentally eliminate the risk of mechanical damage caused by vascular dissection and rupture due to excessive balloon inflation, thus improving the safety of vascular interventional surgery.

[0021] 3. By integrating the core complex control algorithm into the ablation host, the interventional catheter unit can be simplified and its reliability improved. Clinicians only need to set the target vessel diameter or have it automatically identified by the system. Subsequent complex flow calculations and adjustments are all completed automatically by the system, which greatly reduces the technical threshold and training costs of surgical operations and improves the consistency and efficiency of the operation.

[0022] 4. This ablation method only requires setting the working parameters of each unit according to the target blood vessel diameter, simplifying complex fluid control into an intuitive clinical operation. This avoids the excessive reliance on doctors' experience in traditional ablation surgery, thus improving the safety and efficiency of the operation. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the ultrasonic ablation system provided in the embodiments of this application; Figure 2 This is a schematic diagram of the interventional catheter unit in the ultrasonic ablation system provided in the embodiments of this application; Figure 3 This is a flowchart of the ultrasonic ablation method provided in the embodiments of this application; Figure 4 This is a flowchart of the actual surgical procedure for the ultrasonic ablation method provided in the embodiments of this application; Figure 5 This is a flowchart of the closed-loop control algorithm in the ultrasonic ablation method provided in the embodiments of this application; Figure 6 This is a comparison curve between the low-pressure scheme of the ultrasonic ablation method provided in this application embodiment and the high-pressure scheme of the prior art; Figure 7 This is a photograph of the balloon being inflated in the ultrasonic ablation method provided in the embodiments of this application.

[0024] In the diagram: 1. Ablation unit; 2. Interventional catheter unit; 21. Balloon; 22. Ultrasonic transducer; 23. Inner tube; 24. Multi-lumen tube; 25. Divider; 251. Cooling water inlet; 252. Cooling water outlet; 26. Detection unit; 3. First drive unit; 4. First pipeline; 5. Second drive unit; 6. Second pipeline; 7. Cooling unit. Detailed Implementation

[0025] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and design various embodiments with various modifications suitable for a particular purpose.

[0026] Please see Figures 1-2 As shown, this embodiment provides an ultrasound ablation system, including an interventional catheter unit 2 for percutaneous delivery to a target blood vessel. The distal end of the catheter unit 2 is provided with a balloon 21 and an ultrasound transducer 22 located inside the balloon 21. The interventional catheter unit 2 is also provided with an independent inlet channel and an outlet channel. The inlet channel and the outlet channel have the same cross-sectional area and are connected to the inner cavity of the balloon 21. The balloon 21 is made of a compliant material, and the compliant material is medical polyurethane (TPU) with a Shore hardness of 90A.

[0027] It also includes a first drive unit 3 and a second drive unit 5. The first drive unit 3 is connected to the first pipe 4, which is connected to the return water channel; the second drive unit 5 is connected to the second pipe 6, which is connected to the inlet water channel. The ablation host 1, the first drive unit 3 and the second drive unit 5 are all electrically connected to the ablation host 1. The operating parameters of the first drive unit 3 and the second drive unit 5 can be independently adjusted by the ablation host 1 to control the net flow difference between the coolant entering and exiting the balloon 21, causing the balloon 21 to expand and deform. The net flow difference is adjusted to adjust the outer diameter of the balloon 21 to the target diameter.

[0028] It also includes a cooling unit 7 for storing coolant. When in use, the coolant enters the inlet channel of the interventional catheter unit 2 through the second pipeline 6 and the second drive unit 5 and enters the balloon 21. After passing through the return channel, it enters the first pipeline 4 and the first drive unit 3 and flows back to the cooling unit 7. After being cooled, the coolant enters the second pipeline 6 again, forming a closed-loop controlled cooling cycle.

[0029] It is also equipped with a detection unit 26, including a pressure sensor disposed inside the balloon 21 and / or near the end of the return water channel, for real-time monitoring of the pressure inside the balloon 21; The detection unit 26 includes a temperature sensor for monitoring the coolant temperature, and a pressure sensor. The signals monitored by the temperature sensor are fed back to the controller in real time. The controller is located inside the ablation host 1.

[0030] This system ensures continuous and rapid cooling of the balloon 21 through precise flow difference control, achieving excellent thermal management. It also fundamentally eliminates the risk of mechanical damage such as vascular dissection and rupture caused by over-inflation of the balloon 21, thus improving the safety of vascular interventional surgery.

[0031] It is important to understand that the pressure inside balloon 21 satisfies the formula P = (P1 - P2) / 2; Where P is the pressure of the balloon, P1 is the pressure at the inlet of the water inlet channel, and P2 is the pressure at the outlet of the water return channel.

[0032] In actual operation, the pressure at the outlet is approximately -1 atm, and the pressure at the inlet is always less than 3 atm. This net flow difference P is converted into a uniform internal net pressure within the compliant balloon, which is far lower than that of traditional methods and is always below 1 atm. Using this low pressure, the balloon 21 can be gently and stably expanded to the required diameter. It can also reduce the working pressure of the balloon 21 from the high pressure range of 2-6 atm in the existing technology to an extremely low level that is always below 1 atm. The low pressure makes the balloon 21 more flexible, which can better adapt to and conform to irregular blood vessel walls, eliminate gaps, improve the efficiency of ultrasound energy transmission, and achieve more uniform and effective ablation.

[0033] In one specific embodiment, the interventional catheter unit 2 further includes a multi-lumen tube 24, with an inlet water channel and a return water channel axially arranged inside the multi-lumen tube 24. An inner tube 23 is coaxially arranged inside the multi-lumen tube 24, with the distal end of the inner tube 23 extending to the outside of the multi-lumen tube 24. The multi-lumen tube 24 is provided with an inner lumen corresponding to the inner tube 23, and the ultrasonic transducer 22 is fixed on the inner tube 24.

[0034] The proximal end of the balloon 21 is fixed to the outside of the multi-lumen tube 24, and the distal end of the balloon 21 is fixed to the outside of the inner tube 23, so that the inner cavity of the balloon 21 can communicate with the water inlet channel and the water return channel.

[0035] The proximal end of the multi-cavity tube 24 is fixedly connected to the cavity component 25. The cavity component 25 is provided with a cooling water inlet 251 and a cooling water outlet 252. The cooling water inlet 251 is connected to the inlet channel and the second pipeline 6, and the cooling water outlet 252 is connected to the outlet channel and the first pipeline 4.

[0036] Multiple wire cavities are also provided inside the multi-cavity tube 24. The multiple wire cavities are arranged along the axial direction of the multi-cavity tube 24 and are respectively used for the wires of the ultrasonic transducer 22, pressure sensor and temperature sensor. The ultrasonic transducer 22, pressure sensor and temperature sensor are electrically connected to the ablation host 1. The probes of the pressure sensor and temperature sensor are located in the inner cavity of the balloon 21.

[0037] In this embodiment, the first drive unit 3 is a water pump. The inlet of the water pump is connected to the cooling water outlet 252 through the first pipe 4, and the outlet of the water pump is connected to the cooling unit 7 through the first pipe 4.

[0038] The second drive unit 5 is a water inlet pump. The inlet of the water inlet pump is connected to the cooling unit 7 through the second pipe 6, and the outlet of the water inlet pump is connected to the cooling water inlet 251 through the second pipe 6.

[0039] In this embodiment, both the outlet pump and the inlet pump are peristaltic pumps. By controlling the pump speed, the flow rate of coolant in the pipeline can be adjusted, thereby achieving high-precision flow output.

[0040] Both the outlet pump and the inlet pump can be independently adjusted with high precision. Both the outlet pump and the inlet pump are electrically connected to the ablation host 1. The ablation host 1 has a built-in controller for receiving instructions and sensor signals, and outputting control instructions to drive the two pumps to work together to form a dual-pump circulation system.

[0041] In this embodiment, the cooling unit 7 may be a coolant container for holding a mixture of contrast agent and saline solution.

[0042] The directly controlled object in this system is the net flow difference ΔQ between the coolant flowing into and out of the balloon 21, i.e., ΔQ = Q_in - Q_out, where Q_in is the inlet pump flow rate and Q_out is the outlet pump flow rate.

[0043] For a sealed balloon made of a compliant material, the balloon volume will increase slowly when there is a net inflow (ΔQ > 0); conversely, the volume will decrease when there is a net outflow (ΔQ < 0).

[0044] Changes in volume directly lead to changes in pressure (P) within balloon 21, and this relationship is determined by the stress-strain characteristics of the balloon 21 material. By precisely controlling a small, stable ΔQ, a correspondingly small and stable net pressure boost can be generated and maintained within balloon 21.

[0045] By controlling ΔQ at a fine level of milliliters per minute (mL / min), even when the balloon 21 is inflated to its maximum working diameter (e.g., 10 mm), the steady-state pressure generated inside it is far below 1 atm (typical range 0.3-0.9 atm), thus enabling variable diameter balloon 21 with relatively low internal pressure.

[0046] In use, the flow rate (Q_out) of the outlet pump is set and locked at a relatively high constant value (e.g., 30-45 mL / min). This flow rate is sufficient to ensure that the coolant circulates at high speed within the balloon 21 regardless of its state, continuously and efficiently removing the heat generated by the transducer and cooling the blood vessel walls. This fundamentally solves the contradiction between cooling and diameter variation, achieving diameter variation only by adjusting the flow rate (Q_in) of the inlet pump. When expansion is required, Q_in = Q_out + |ΔQ_target|; when contraction is required, Q_in = Q_out - |ΔQ_target|, where ΔQ_target is a small flow rate value calculated by the controller based on the target balloon diameter.

[0047] In this ultrasound ablation system, a dual-pump circulation system is used to achieve high-precision flow regulation, which ensures continuous high-speed cooling of the balloon 21 while reducing the pressure of the balloon 21 during operation. The low pressure makes the balloon 21 more flexible, which can better adapt to and conform to the irregular blood vessel wall, eliminate gaps, improve the efficiency of ultrasound energy transmission, and achieve more uniform and effective ablation.

[0048] Employing a closed-loop control algorithm based on pressure feedback, the system can achieve continuous, precise, and adaptive adjustment of the balloon size 21. Combined with the highest priority safety monitoring mechanism, the system has intelligent error prevention and self-protection capabilities, and high operational fault tolerance.

[0049] By integrating the core complex control algorithm into the ablation host 1, the interventional catheter unit 2 can be simplified and its reliability improved. Clinicians only need to set the target vessel diameter or have it automatically identified by the system. Subsequent complex flow calculations and adjustments are all completed automatically by the system, which greatly reduces the technical threshold and training costs of surgical operations and improves the consistency and efficiency of the operation.

[0050] See Figure 3 As shown, a method using an ultrasonic ablation system includes the following specific steps: S1. Determine the target diameter of the balloon based on the target blood vessel diameter; S2. Match the target diameter of the spherical bag with the mapping table to determine the target net flow difference, the first flow rate, and the second flow rate; S3. Start the first drive unit to run at the first flow rate, the balloon expands to the nominal diameter, the coolant forms a cooling cycle inside the balloon, and the detection unit monitors the internal pressure of the balloon in real time. S4. Start the second drive unit to operate at the second flow rate, and generate expansion pressure by accumulating in the balloon through the target net flow rate difference, driving the balloon to expand to the target diameter; S5. In real time, determine whether the actual pressure inside the balloon is less than the preset P_max. If yes, proceed to the next step; otherwise, control the first drive unit and / or the second drive unit to decelerate and depressurize the balloon. S6. Keep the balloon stable at the target diameter and perform ultrasonic ablation.

[0051] This ablation method simplifies complex fluid control into intuitive clinical operation by simply setting the working parameters of each unit according to the target blood vessel diameter. This avoids the excessive reliance on doctors' experience in traditional ablation surgery, thus improving the safety and efficiency of the procedure.

[0052] In this ablation method, the first flow rate can set and maintain a relatively high base flow rate to ensure that regardless of the inflation state of the balloon, the coolant can circulate at a high speed inside it, continuously carry away the heat generated by the ultrasonic transducer, and effectively cool the vascular intima. The base flow rate of the water pump is about -1 atm for the pressure inside the balloon, and the pressure at the water inlet is always less than 3 atm, which reduces the working pressure of the balloon 21 to an extremely low level that is always lower than 1 atm. The low pressure makes the balloon 21 softer, enabling it to better adaptively conform to the irregular blood vessel wall, eliminate gaps, improve the ultrasonic energy transfer efficiency, and achieve more uniform and effective ablation.

[0053] Refer to Figure 4 As shown, after the operation starts, the interventional catheter unit inserts the sheath tube to deliver the balloon to the target blood vessel; if the balloon is not in place, continue to adjust the position of the balloon, and if the balloon is in place, the ablation host and the drive unit initialize the system; Select the operation mode. The doctor sets the target blood vessel diameter or the system automatically identifies the target blood vessel diameter. The controller receives the target net flow difference (ΔQ_target), calls the core control algorithm, the drive unit moves in coordination, and the pressure sensor monitors the pressure inside the balloon in real time; Judge whether the balloon reaches the target diameter and the pressure P < P_max. If not, continue to call the core control algorithm and then proceed to the next step; if so, the balloon enters the stable ablation state and maintains the state for ultrasonic ablation; Judge whether it is necessary to adjust the position or diameter. If so, the ablation host and the drive unit re-initialize the system and then proceed to the next step; if not, the ablation ends and the recovery mode is started; [[ID=,13]]Reverse the flow difference to shrink the balloon and complete the operation.

[0054] In this embodiment, the balloon is a compliant balloon, and the actual pressure P inside the balloon is less than 1 atm.

[0055] The balloon is inflated by generating a net flow difference inside the balloon. On the one hand, the structure of the balloon is simple, without the need to design complex internal flow channels, with a lower cost, and also avoiding the hidden danger of rupture caused by excessive internal pressure accumulation when the balloon is working. On the other hand, the continuous high-speed cooling flow inside the balloon can ensure the heat dissipation of the balloon, and the outer wall of the balloon is softer, enabling it to better adaptively conform to the irregular blood vessel wall, eliminate gaps, improve the ultrasonic energy transfer efficiency, and achieve more uniform and effective ablation.

[0056] In this embodiment, the first drive unit is a water pump, the first flow rate is the base flow rate, match the target blood vessel diameter with the preset mapping table, determine the initial target net flow difference when the water pump operates at the first flow rate, and set the water pump to operate at the base flow rate.

[0057] The base flow rate is a constant cooling flow rate, which allows the coolant to form a basic cooling cycle within the balloon for cooling the balloon.

[0058] In this embodiment, the second driving unit is an inlet pump. It compares the target diameter of the balloon with a preset mapping table to obtain a net flow difference between the inlet flow rate and the return flow rate of the balloon. The inlet pump is set to operate at a second flow rate, which is the sum of the first flow rate and the net flow difference.

[0059] Driven by the inlet and outlet pumps, the coolant begins to circulate, the balloon begins to inflate, and the pressure sensor inside the balloon feeds back the pressure signal to the ablation host in real time. The ablation host adjusts the second flow rate through the PI algorithm to keep the steady-state working pressure inside the balloon stable. At this time, the outer diameter of the balloon remains stable. Throughout the process, because the first flow rate remains high and constant, the coolant continues to flow, effectively controlling the temperature of the balloon and the blood vessel wall.

[0060] If it is necessary to change the ablation site or adapt to different blood vessel segments, the doctor only needs to input the new target diameter, and the ablation host will automatically calculate the new net flow difference and adjust the inlet pump to run at a different flow rate to keep the steady-state working pressure inside the balloon stable.

[0061] If an abnormal situation occurs that causes the pressure inside the balloon to rise abnormally close to P_max (1.0 atm), this circuit will be triggered immediately to forcibly adjust the pump speed to release pressure and ensure safety.

[0062] After the ablation is complete, the controller sets the net flow difference to a negative value, allowing the coolant inside the balloon to flow out net, the balloon to contract to a folded state, and then the catheter is safely withdrawn.

[0063] In one specific implementation, see [reference] Figure 5 As shown, the core closed-loop control algorithm executed by the controller in this ultrasonic ablation method follows this process: The ablation unit 1 inputs the target balloon diameter (D_target), queries the preset "diameter-target net flow rate difference (ΔQ_target)" mapping table, calculates the initial target net flow rate difference ΔQ_target, adopts a constant speed strategy for the outlet pump, sets Q_out=Q_base, where Q_base is the preset base flow rate, and calculates and sets the inlet flow rate: Q_in=Q_base+ΔQ_target; Based on the actual pressure (P_actual) fed back by the pressure sensor as the core controlled variable, the controller compares P_actual with the expected pressure (P_expected) corresponding to the current target diameter, and reads the actual pressure value P_actual from the pressure sensor in real time. It also continuously compares P_actual with a preset absolute safety pressure upper limit P_max. If P_expected ≥ P_max (e.g., 0.9 atm) is detected, the safety protocol is executed: immediately forcefully decrease ΔQ_target or increase Q_out to make ΔQ_target negative, quickly depressurize, and ensure that the balloon pressure will not exceed the safety limit under any circumstances; If P_expected < P_max, then calculate the pressure deviation e: e = P_expected - P_actual; The proportional-integral (PI) algorithm is used to calculate the adjustment ΔQ_adjustment to ΔQ_target. ΔQ_adjustment=Kpe+Ki∫edt; where Kp and Ki are adjustable parameters; The controller dynamically adjusts Q_in to ensure that P_actual is precisely stable near P_expected. Based on the deviation between the pressure setpoint and the actual pressure value and its integral value, the controller calculates the action of the actuator (such as a control valve or pump) and updates the target flow difference in real time. ΔQtarget = ΔQ_target_initial + ΔQ_adjustment: This achieves precise pressure control without steady-state error. For example, if the actual pressure is lower than the preset pressure value (positive error), the controller will increase the flow rate or opening (positive ΔQ_target) to raise the pressure. Conversely, if the actual pressure is higher than the preset pressure value (negative error), the controller will decrease the flow rate or opening (negative ΔQ_target) to lower the pressure. By adjusting Kp and Ki, the response speed of the ablation system can be adjusted, thereby achieving precise and stable diameter control. Once the system reaches stability, the pressure sensor values ​​are read in real time. The algorithm continuously monitors minute fluctuations in pressure and determines whether the fluctuations exceed the threshold. If the fluctuations exceed the allowable range due to vascular pulsation, patient movement, or other reasons, the controller automatically performs milliliter-level flow compensation to quickly restore stability. This ensures that the balloon size remains constant while maintaining the high-speed cooling cycle.

[0064] To facilitate a full understanding and implementation of the present invention, two non-limiting specific embodiments are provided: The balloon material is made of medical-grade polyurethane (TPU) with a Shore hardness of 90A.

[0065] Use case 1: Target diameter 6.0mm; The controller determines the initial ΔQ_target = +5 mL / min based on the mapping table; If Q_out is set to 30 mL / min (constant base cooling flow rate), then Q_in is set to 35 mL / min. After the system was running, the pressure sensor feedback P_actual stabilized at around 0.6 atm. During the ultrasonic ablation process, the return water temperature monitoring showed a temperature rise of ≤2°C.

[0066] Use case 2: Target diameter 9.0mm; Adjust ΔQ_target = +15 mL / min.

[0067] Keep Q_out = 30 mL / min constant, and adjust Q_in = 45 mL / min.

[0068] Once the system stabilizes, P_actual is approximately 0.8 atm, which is still far below the safe limit of 1 atm.

[0069] See Figure 6 As shown, with the balloon diameter as the horizontal axis and the stable working pressure inside the balloon as the vertical axis, the blue curve represents the balloon diameter in this invention from 4mm to 10mm. As the outer diameter of the balloon increases, the stable working pressure inside the balloon gradually increases from about 0.2 atm to below 1.0 atm. The stable working pressure inside the balloon is always below 0.9 atm, which brings an exponential improvement in vascular safety.

[0070] The red curve represents the existing technology. Starting from 4mm, the stable working pressure inside the balloon is at a high level of 2atm, and it rapidly climbs to 6atm as the balloon diameter increases. The huge pressure difference between the two curves visually highlights the low-pressure safety advantage of the present invention.

[0071] Compared to existing high-pressure technologies, which require an internal pressure of up to 4 atm to achieve an 8mm diameter expansion, this invention achieves a larger diameter (9mm) with an operating pressure of only 0.8 atm, just one-fifth of existing technologies.

[0072] See Figure 7 As shown in the image, during actual testing, the balloon inflated to 6mm under dual-pump control, and the ultrasonic transducer 22 was centered to ensure uniform ablation.

[0073] Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art and related fields based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described and explained in the present invention, unless otherwise specified or limited, shall be implemented according to conventional means in the art.

Claims

1. An ultrasound ablation system, comprising an interventional catheter unit, wherein a balloon is disposed distally thereto and an ultrasound transducer located within the balloon, characterized in that, The interventional catheter unit is also provided with independent inlet and outlet water channels, which are respectively connected to the inner lumen of the balloon. The balloon is made of compliant material. It also includes a first drive unit and a second drive unit, the first drive unit being connected to a first pipeline, and the first pipeline being connected to a return water channel; The second drive unit is connected to the second pipeline, and the second pipeline is connected to the water inlet channel; The ablation host, the first drive unit and the second drive unit are both electrically connected to the ablation host. The ablation host independently adjusts the first drive unit and the second drive unit to control the net flow difference between the coolant entering and leaving the balloon, causing the balloon to expand and deform. Adjusting the net flow difference adjusts the outer diameter of the balloon to the target diameter.

2. The ultrasonic ablation system according to claim 1, characterized in that, The first drive unit is a water pump. The inlet of the water pump is connected to the cooling water outlet through a first pipe, and the outlet of the water pump is connected to the cooling unit through a first pipe.

3. The ultrasonic ablation system according to claim 1, characterized in that, The second drive unit is a water inlet pump. The inlet of the water inlet pump is connected to the cooling unit through a second pipeline, and the outlet of the water inlet pump is connected to the cooling water inlet through a second pipeline.

4. The ultrasonic ablation system according to claim 1, characterized in that, It also includes a cooling unit for storing coolant. The coolant enters the balloon through the water inlet channel of the interventional catheter unit via the second pipeline and the second drive unit, and then flows back to the cooling unit through the water return channel into the first pipeline and the first drive unit.

5. The ultrasonic ablation system according to claim 1, characterized in that, It is also equipped with a detection unit, including a pressure sensor located inside the balloon and / or near the return water channel, for real-time monitoring of the pressure inside the balloon.

6. The ultrasonic ablation system according to claim 5, characterized in that, The detection unit also includes a temperature sensor for monitoring the coolant temperature, and the signals monitored by the pressure sensor and temperature sensor are fed back to the controller in real time. The controller is located inside the ablation host.

7. The ultrasonic ablation system according to claim 1, characterized in that, The interventional catheter unit includes a multi-lumen tube, with an inlet water channel and an outlet water channel axially arranged inside the multi-lumen tube. An inner tube is coaxially arranged inside the multi-lumen tube, with the distal end of the inner tube extending to the outside of the multi-lumen tube. The multi-lumen tube has an inner lumen corresponding to the inner tube, and an ultrasonic transducer is fixed on the inner tube.

8. A method for ultrasonic ablation, using the ultrasonic ablation system according to any one of claims 1-7, characterized in that, The specific steps are as follows: S1. Determine the target diameter of the balloon based on the target blood vessel diameter; S2. Match the target diameter of the spherical bag with the mapping table to determine the target net flow difference, the first flow rate, and the second flow rate; S3. Start the first drive unit to run at the first flow rate, the balloon expands to the nominal diameter, the coolant forms a cooling cycle inside the balloon, and the detection unit monitors the internal pressure of the balloon in real time. S4. Start the second drive unit to operate at the second flow rate, and generate expansion pressure by accumulating in the balloon through the target net flow rate difference, driving the balloon to expand to the target diameter; S5. In real time, determine whether the actual pressure inside the balloon is less than the preset P_max. If yes, proceed to the next step; otherwise, control the first drive unit and / or the second drive unit to decelerate and depressurize the balloon. S6. Keep the balloon stable at the target diameter and perform ultrasonic ablation.

9. The ultrasonic ablation method according to claim 1, characterized in that, The stable actual pressure inside the balloon is less than 1 atm.

10. The ultrasonic ablation method according to claim 1, characterized in that, The first flow rate is the base flow rate, which is a constant cooling flow rate, so that the coolant forms a basic cooling cycle inside the bladder; The second flow rate is the sum of the difference between the first flow rate and the net flow rate.

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