CN115530962A - Thermal ablation system and method for controlling flowing medium in thermal ablation system - Google Patents
Thermal ablation system and method for controlling flowing medium in thermal ablation system Download PDFInfo
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- 238000002679 ablation Methods 0.000 title claims abstract description 153
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- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 175
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- 238000007674 radiofrequency ablation Methods 0.000 claims abstract description 18
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- 239000002504 physiological saline solution Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 1
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- 210000004185 liver Anatomy 0.000 description 1
- 239000013307 optical fiber Substances 0.000 description 1
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Abstract
The application relates to the field of thermal ablation systems and control thereof, and discloses a thermal ablation system and a control method of a flowing medium in the thermal ablation system. The heat ablation system comprises a radio frequency ablation probe, a pressure liquid nitrogen source and a heat exchange evaporation unit connected between the ablation probe and the pressure liquid nitrogen source, wherein the heat exchange evaporation unit is provided with a gas-liquid separator; the control method comprises the following steps: adjusting the rear-end flow resistance of the gas-liquid separator to control the temperature of the nitrogen flowing into the ablation probe to be kept in a preset temperature range; and detecting the head temperature of the ablation probe, and adjusting the rear-end flow resistance of the ablation probe according to the detected head temperature and the set radio frequency power so as to enable the head temperature to be the target temperature. Embodiments of the present application avoid tissue carbonization due to high temperatures around the probe while providing a greater ablation range.
Description
Technical Field
The present application relates to the field of thermal ablation systems and control thereof, and more particularly, to a method and system for controlling a flowing medium in a thermal ablation system.
Background
Thermal ablation is mainly divided into radiofrequency ablation and microwave ablation. If no flowing medium is introduced into the thermal ablation system, the biggest influence on the radiofrequency ablation is that tissues around the probe are quickly dehydrated and carbonized in the ablation process, so that a radiofrequency loop is cut off, the radiofrequency ablation cannot be continued, and the ablation of a target focus is incomplete. The microwave ablation also faces the problem that the ablation efficiency is affected by the carbonized tissues, meanwhile, the carbonized tissues are adhered around the ablation probe, the tissues can be torn, the exit after the treatment is not facilitated, and the microwave probe is serious in self-heating and is easy to burn normal tissues near the needle channel.
The currently commonly used flowing medium is saline driven by a peristaltic pump, and a high-pressure gas is used as the flowing medium in the ablation probe by a special device. For example, a conventional scheme 1 that uses a peristaltic pump to drive physiological saline as a flowing medium has advantages that the physiological saline is simple and easy to obtain, but parameters of the peristaltic pump are usually fixed, a rotating speed cannot be adjusted according to an ablation power and a tissue state, the protection capability of a biological tissue is insufficient, a region where the tissue is dehydrated and carbonized is only about 2 mm away from the surface of an ablation probe, and an effect of expanding an ablation range is insufficient. For example, a prior art 2 using high-pressure gas as a flowing medium inside a microwave ablation probe has the advantages of stronger protection capability on biological tissues, and can produce a larger ablation range compared with the technical scheme 1, but has no mature control scheme, but has the disadvantages that the gas pressure is adjusted by a hand valve, and serious tissue carbonization still exists in a place where the head of the ablation probe is not cooled, and even the ablation probe burns out.
In addition, the prior art also discloses a prior scheme 3 of using high-pressure gas as a flowing medium in a radio frequency ablation probe, which needs to use a throttling principle to control the size of freezing power and has the advantages of strong controllability, but the gas pressure is usually higher than 2MPa under the throttling principle, certain transportation and storage qualifications are needed, meanwhile, the throttling principle has the problems of slow cooling and complex equipment, a large amount of time is needed for precooling, and the equipment cost is also high. And a paper 'control mode of a novel air-cooled radio frequency ablation system' based on the existing scheme 3 only describes that the temperature of the probe is controlled to be 80-90 ℃ by adopting a conventional PID algorithm in the radio frequency process, and the described system has large hysteresis and low precision and still has the problem of great carbonization of tissues around the probe.
Disclosure of Invention
The present application aims to provide a thermal ablation system and a method for controlling a flowing medium in the thermal ablation system, which can avoid tissue carbonization caused by high temperature around a probe while providing a larger ablation range.
The application discloses a method for controlling a flowing medium in a thermal ablation system, wherein the thermal ablation system comprises a radio frequency ablation probe, a pressure liquid nitrogen source and a heat exchange evaporation unit connected between the ablation probe and the pressure liquid nitrogen source, and the heat exchange evaporation unit is provided with a gas-liquid separator;
the control method comprises the following steps:
a, adjusting the rear end flow resistance of the gas-liquid separator to control the temperature of nitrogen flowing into the ablation probe to be kept within a preset temperature range;
b, detecting the head temperature of the ablation probe, and adjusting the rear-end flow resistance of the ablation probe according to the detected head temperature and the set radio frequency power so as to enable the head temperature to be the target temperature.
In a preferred embodiment, the predetermined temperature range is-140 ℃ to-130 ℃, and the target temperature is between 0 ℃ and-40 ℃.
In a preferred embodiment, step B further comprises:
detecting the head temperature of the ablation probe, calculating the control voltage of a rear-end flow regulating device of the ablation probe by adopting a first formula and a second formula according to the detected head temperature, the set radio frequency power and the target temperature, and generating and outputting the control voltage to a control end of the flow regulating device at the rear end of the ablation probe so as to adjust the rear-end flow resistance of the ablation probe; wherein,
the first formula is:
the second formula is: error r N ＝T-T set ；
Wherein, error N At the current momentTemperature error, k P Is the power term proportionality coefficient, k T Is a temperature term proportionality coefficient, T is the detected head temperature, P is the set RF power, T set And V is the control voltage of the rear end flow regulating device of the ablation probe.
In a preferred embodiment, step a further comprises:
detecting the nitrogen temperature of the ablation probe;
and when the detected nitrogen temperature is higher than a second threshold value, opening the flow regulating device at the rear end of the gas-liquid separator and/or increasing the voltage applied to the flow regulating device so as to control the temperature of the nitrogen flowing into the ablation probe to be kept within the preset temperature range between the first threshold value and the second threshold value.
In a preferred embodiment, the method further comprises the following steps:
performing steps A to B in real time or periodically to maintain the head temperature at the target temperature.
The application also discloses a thermal ablation system, which comprises a radio frequency ablation probe, a pressure liquid nitrogen source and a heat exchange evaporation unit connected between the ablation probe and the pressure liquid nitrogen source, wherein the heat exchange evaporation unit is provided with a gas-liquid separator;
the thermal ablation system further comprises:
a first flow resistance control unit configured to adjust a rear end flow resistance of the gas-liquid separator to control a temperature of nitrogen flowing into the ablation probe to be maintained within a predetermined temperature range;
the second flow resistance control unit is configured to detect the head temperature of the ablation probe and adjust the rear end flow resistance of the ablation probe according to the detected head temperature and the set radio frequency power so as to enable the head temperature to be a target temperature.
In a preferred embodiment, the predetermined temperature range is-140 ℃ to-130 ℃, and the target temperature is between 0 ℃ and-40 ℃.
In a preferred embodiment, the second flow resistance control unit includes a second temperature detection device, a second voltage adjustment module, and a second flow regulation device disposed at the rear end of the ablation probe;
the second temperature detection device is configured to detect a head temperature of the ablation probe;
the second voltage adjusting module is configured to calculate a control voltage of the second flow regulating device according to the detected head temperature of the ablation probe, the set radio frequency power and the target temperature by adopting a first formula and a second formula, and generate and output the control voltage to a control end of the first flow regulating device so as to adjust the rear end flow resistance of the ablation probe, wherein the first formula is
The second formula is error N ＝T-T set Wherein error r N Temperature error at the present time, k P Is the power term scaling factor, k T Is a temperature term scaling factor, T is the detected head temperature, P is the set RF power, T set V is a control voltage of the second flow regulating device for the target temperature.
In a preferred embodiment, the first flow resistance control unit includes a first temperature detection device, a first voltage adjustment module, and a first flow rate adjustment device disposed at a rear end of the gas-liquid separator;
the temperature detection device is configured to detect a nitrogen temperature of the ablation probe;
the first voltage adjustment module is configured to turn off the first flow rate adjustment device or reduce a control voltage applied to the first flow rate adjustment device when the detected nitrogen temperature is less than a first threshold, and turn on the flow rate adjustment device at the rear end of the gas-liquid separator and/or increase the control voltage applied to the first flow rate adjustment device when the detected nitrogen temperature is greater than a second threshold, so as to control the temperature of nitrogen flowing into the ablation probe to be maintained within the predetermined temperature range between the first threshold and the second threshold.
In a preferred example, the first flow resistance control unit and the second flow resistance control unit are alternately periodically executed to maintain the head temperature at the target temperature.
The embodiment of the application at least comprises the following advantages and beneficial effects:
in the radio frequency ablation process, the liquid nitrogen phase change evaporation is used as the low-temperature nitrogen, and the ambient temperature of the ablation probe is stabilized at the temperature within the subzero preset temperature range by controlling the flow of the low-temperature nitrogen in the system. Compared with water circulation, the temperature of the ablation probe can be controlled to be 0-40 ℃, more redundant heat can be absorbed, the occurrence of tissue carbonization is delayed, a larger ablation range is obtained, the problem is favorably solved better, and the conventional water circulation generally needs more than 0 ℃, and the excessively low temperature can freeze the periphery of the ablation probe, influence the output of radio frequency energy and cause the ablation process to be interrupted accidentally and cause incomplete ablation. Therefore, the embodiment of the present application can achieve a larger ablation range than the technical solution 1, and at the same time, better controllability than the technical solution 2.
Furthermore, an improved radio frequency ablation control algorithm is provided according to the characteristics of the internal cooling circulation radio frequency ablation large-lag system, the low-temperature nitrogen obtained through phase change can be quickly controlled and/or kept at a preset temperature below zero, and the method is small in overshoot and fluctuation. Therefore, compared with the technical scheme 3, the improved control algorithm provided by the embodiment of the application can better deal with the problem of large hysteresis of the system, has small overshoot and high precision, and is cheap and easy to obtain because the low-temperature nitrogen is obtained from the evaporation of the liquid nitrogen.
A large number of technical features are described in the specification of the present application, and are distributed in various technical solutions, so that the specification is too long if all possible combinations of the technical features (i.e., the technical solutions) in the present application are listed. In order to avoid this problem, the respective technical features disclosed in the above summary of the invention of the present application, the respective technical features disclosed in the following embodiments and examples, and the respective technical features disclosed in the drawings may be freely combined with each other to constitute various new technical solutions (which are considered to have been described in the present specification) unless such a combination of the technical features is technically infeasible. For example, in one example, feature a + B + C is disclosed, in another example, feature a + B + D + E is disclosed, and features C and D are equivalent technical means that serve the same purpose, technically only one feature is used, but not both, and feature E may be technically combined with feature C, then the solution of a + B + C + D should not be considered as already described because the technology is not feasible, and the solution of a + B + C + E should be considered as already described.
Drawings
FIG. 1 is a schematic diagram of a thermal ablation system according to a first embodiment of the present application.
FIG. 2 is a flow chart illustrating a method for controlling a flowing medium in a thermal ablation system according to a second embodiment of the present application.
FIG. 3 is a flow chart illustrating a method for controlling a flowing medium in thermal ablation according to an embodiment of the present application.
FIG. 4 is a graph of the proportional valve control voltage at the back end of the probe and the tip temperature control results according to one embodiment of the present application.
FIG. 5 is a graph of proportional valve control voltage at the back end of a gas-liquid separator and nitrogen inlet temperature change, according to one embodiment of the present application.
Detailed Description
In the following description, numerous technical details are set forth in order to provide a better understanding of the present application. However, it will be understood by those skilled in the art that the technical solutions claimed in the present application may be implemented without these technical details and with various changes and modifications based on the following embodiments.
To make the objects, technical solutions and advantages of the present application more clear, embodiments of the present application will be described in further detail below with reference to the accompanying drawings.
A first embodiment of the present application relates to a thermal ablation system, as shown in fig. 1, comprising a radiofrequency ablation probe, a pressure liquid nitrogen source, a heat exchange evaporation unit connected between the ablation probe and the pressure liquid nitrogen source. Wherein, the pressure liquid nitrogen source is a liquid nitrogen container with certain pressure, and the pressure is used for leading the liquid nitrogen to flow to the ablation probe through a pipeline. The liquid nitrogen is liquid nitrogen and has the characteristic of low temperature, and the temperature of the liquid nitrogen is-196 ℃ under normal pressure. The heat exchange evaporation unit is, for example but not limited to, a pipeline connecting the ablation probe and a pressure liquid nitrogen source, liquid nitrogen flows into the heat exchange evaporation unit, and low-temperature nitrogen flows out of the heat exchange evaporation unit. After the liquid nitrogen is evaporated, the liquid nitrogen is changed into nitrogen gas to generate huge flow resistance, so that the flow of the liquid nitrogen is slowed down or even stopped, the heat exchange time is too long, and the temperature is too high after the liquid nitrogen reaches the ablation probe. Therefore, the heat exchange evaporation unit also comprises a gas-liquid separator, and the flow velocity of liquid nitrogen is controlled by adjusting the flow resistance at the rear end of the gas-liquid separator, so that the nitrogen entering the ablation probe is ensured to have a sufficiently low temperature.
Optionally, the thermal ablation system further comprises a control unit comprising a first flow resistance control unit and a second flow resistance control unit. The first flow resistance control unit is configured to adjust a rear end flow resistance of the gas-liquid separator to control a temperature of nitrogen flowing into the ablation probe to be maintained within a predetermined temperature range. Optionally, the first flow resistance control unit includes a first temperature detection device, a first voltage adjustment module, and a first flow rate adjustment device disposed at a rear end of the gas-liquid separator, wherein the first temperature detection device is configured to detect a nitrogen temperature of the ablation probe, the first voltage adjustment module is configured to close the flow rate adjustment device at the rear end of the gas-liquid separator or decrease a control voltage applied to the first flow rate adjustment device when the detected nitrogen temperature is less than a first threshold, and open the flow rate adjustment device at the rear end of the gas-liquid separator and/or increase the control voltage applied to the first flow rate adjustment device when the detected nitrogen temperature is greater than a second threshold, so as to control the nitrogen temperature flowing into the ablation probe to be maintained within the predetermined temperature range between the first threshold and the second threshold. For example, in one embodiment, the first flow resistance control unit comprises a flow rate adjusting device arranged at the rear end of the gas-liquid separator and the temperature measuring device arranged at the liquid nitrogen inlet. Wherein the temperature measuring device may be, but is not limited to, a thermocouple, etc. The first flow regulating device may be a proportional valve, or may be a device and structure for controlling flow, such as an electromagnetic valve and a hand valve. For example, the first flow regulating device is a proportional valve, and in one embodiment, the nitrogen gas is considered to be at too high a temperature when the temperature measured by a thermocouple at the liquid nitrogen inlet is higher than-130 ℃; when the temperature measured by the thermocouple at the liquid nitrogen inlet is lower than-140 ℃, the temperature of the nitrogen is considered to be too low, and the proportional valve at the rear end of the gas-liquid separator is closed, namely the applied voltage is 0V.
Further, the second flow resistance control unit is configured to detect the head temperature of the ablation probe, and adjust the rear end flow resistance of the ablation probe according to the detected head temperature and the set radio frequency power so as to enable the head temperature to be the target temperature. Optionally, the second flow resistance control unit includes a second temperature detection device, a second voltage adjustment module, and a second flow regulation device disposed at the rear end of the ablation probe. Wherein the second temperature detection device is configured to detect a head temperature of the ablation probe; the second voltage adjusting module is configured to calculate a control voltage of the second flow regulating device according to the detected head temperature of the ablation probe, the set radio frequency power and the target temperature by adopting a first formula and a second formula, and generate and output the control voltage to a control end of the second flow regulating device so as to adjust the rear end flow resistance of the ablation probe, wherein the first formula is
The second formula is error N ＝T-T set Wherein error N For temperature error at the present moment, k P Is the power term proportionality coefficient, k T Is a temperature term proportionality coefficient, T is the detected head temperature, P is the detected head temperatureSet radio frequency power, T set V is the control voltage of the second flow regulating device for the target temperature.
The second temperature sensing device is integrated into the ablation probe head, such as but not limited to a thermocouple, embedded inside the ablation probe, so that the combined thermal effects of the internal flowing medium and thermal ablation can be measured. Or,
optionally, the first flow resistance control unit and the second flow resistance control unit are alternately periodically executed to maintain the head temperature at the target temperature.
In one embodiment, the system adjusts the flow resistance at the rear end of the ablation probe through the temperature value detected by the second flow resistance control unit, thereby controlling the flow rate of the low-temperature nitrogen to control the temperature of the nitrogen flowing into the ablation probe to be kept in a preset temperature range of-140 ℃ to-130 ℃, and also adjusting the flow resistance at the rear end of the gas-liquid separator to control the temperature of the ablation probe to be in a target temperature range of 0 ℃ to-40 ℃ if the temperature of the nitrogen detected by the first flow resistance control unit is not low enough. In other embodiments, the predetermined temperature range and the target temperature range may have other values, such as may be experimentally obtained from a pipeline configuration.
A second embodiment of the present application relates to a method for controlling a flowing medium in a thermal ablation system, the thermal ablation system includes a radio frequency ablation probe, a pressure liquid nitrogen source, and a heat exchange evaporation unit connected between the ablation probe and the pressure liquid nitrogen source, the heat exchange evaporation unit is provided with a gas-liquid separator, and the flow of the control method is as shown in fig. 2, the control method includes the following steps:
Optionally, the predetermined temperature range is-140 ℃ to-130 ℃, and the target temperature is a temperature value between 0 ℃ and-40 ℃.
Optionally, the step 202 may further include: detecting the head temperature of the ablation probe, and applying a first formula based on the detected head temperature, the set RF power, and the target temperature
And a second formula error N ＝T-T set And calculating the control voltage of the rear-end flow regulating device of the ablation probe, and generating and outputting the control voltage to the control end of the flow regulating device at the rear end of the ablation probe so as to adjust the rear-end flow resistance of the ablation probe. Wherein, error N For temperature error at the present moment, k P Is the power term proportionality coefficient, k T Is a temperature term proportionality coefficient, T is the detected head temperature, P is the set RF power, T set V is the control voltage of the rear end flow regulating device of the ablation probe for the target temperature.
Optionally, the step 201 further comprises the following steps 201a and 201b:
step 201a, detecting the nitrogen temperature of the ablation probe;
and step 201b, when the detected temperature of the nitrogen is less than a first threshold value, closing a flow regulating device at the rear end of the gas-liquid separator or reducing the voltage applied to the flow regulating device, and when the detected temperature of the nitrogen is greater than a second threshold value, opening the flow regulating device at the rear end of the gas-liquid separator and/or increasing the voltage applied to the flow regulating device so as to control the temperature of the nitrogen flowing into the ablation probe to be kept within the preset temperature range between the first threshold value and the second threshold value.
Optionally, the control method further includes: steps 201 to 202 are performed in real time or periodically to maintain the head temperature at the target temperature.
In order to better understand the beneficial effects of the present application, the following description will take the example that the rf ablation probe continuously heats the excised pig liver with 60W power to control the temperature of the ablation probe between 0 ℃ and-40 ℃, referring to fig. 3, which includes the following steps:
step 301: firstly, a valve of a liquid nitrogen tank is opened, and the pressure of the liquid nitrogen tank is between 0.8MPa and 1.2 MPa. The liquid nitrogen flows through a pipeline connecting the ablation probe and a pressure liquid nitrogen source under the driving of pressure, and exchanges heat and evaporates to be low-temperature nitrogen. The pipeline is provided with a gas-liquid separator, the flow velocity of liquid nitrogen is controlled by adjusting the flow resistance at the rear end of the gas-liquid separator, so that the nitrogen entering the ablation probe is ensured to have low enough temperature, and the flow resistance of the gas-liquid separator is adjusted, namely the control voltage of a proportional valve at the rear end of the gas-liquid separator is adjusted.
Step 302: and acquiring the temperature measured by the thermocouple at the tip of the radio frequency ablation needle, storing the temperature in a storage medium, and reading the temperature in real time by a program.
Step 303: in this embodiment, the target tip temperature of the rf ablation needle is set between 0 ℃ and-40 ℃, the set rf ablation power P and the rf ablation needle tip temperature T obtained in step 302 are used as inputs, and the control voltage of the proportional valve at the rear end of the ablation probe is calculated by using the following control equation:
error N ＝T+15error N ＝T-T set
wherein V is the calculated control voltage of the proportional valve at the rear end of the ablation probe, k P Is the power term proportionality coefficient, k T As a temperature term proportionality coefficient, error N Temperature error at the present time, T set Is the target tip temperature of the radiofrequency ablation needle. In this embodiment, the variation relationship between the control voltage V of the proportional valve at the rear end of the ablation probe and the temperature T of the tip of the radiofrequency ablation probe is shown in fig. 4.
Step 304: the voltage V calculated in step 303 is applied to the ablation probe rear proportional valve and the flow of nitrogen in the ablation probe is between 0 and 100L/min.
Step 306: when it is determined in step 305 that the nitrogen gas temperature is too high, the proportional valve at the rear end of the gas-liquid separator needs to be opened in step 301, and in the present embodiment, the voltage applied to the proportional valve at the rear end of the gas-liquid separator is 1V. The voltage may also be other values, and the numerical value in this embodiment is obtained through a pipeline structure experiment. The proportional valve control voltage at the back end of the gas-liquid separator and the temperature change of the nitrogen inlet are shown in figure 5.
Through the analysis and the experiment of the embodiment, the temperature of the ablation probe can be quickly stabilized at a target temperature value within a certain temperature range of 0 ℃ to-40 ℃ under the condition of realizing a larger ablation range, the maximum overshoot is within 3 ℃, the fluctuation after stabilization is less than +/-0.5 ℃, the supercooling or overheating around the ablation probe is avoided, and the purpose of controlling the ablation range is achieved.
The first embodiment is a method embodiment corresponding to the present embodiment, and the technical details in the first embodiment may be applied to the present embodiment, and the technical details in the present embodiment may also be applied to the first embodiment.
It should be noted that the ablation probe in this application may be needle-type, or may be flat-head-type, or may be other. The flow regulating device can be a proportional valve, and can also be a device and a structure for controlling flow, such as an electromagnetic valve, a hand valve and the like. The temperature measuring unit can be a thermocouple arranged in the ablation probe, and also can be an optical fiber, an external thermocouple, or non-contact MR, ultrasonic temperature measurement and the like. In addition, the improved temperature control algorithm can be used, and adaptive control algorithms such as PID control, sliding mode control, fuzzy control, neural network, genetic algorithm, predictive control, quadratic optimal control, time delay control and estimation based on uncertain disturbance can also be used. The input of the control unit of the present application may be temperature, or additionally input flow rate, pressure, output power of thermal ablation, and tissue impedance, and the output may be target flow rate, or target output power of thermal ablation, target pressure, and target tissue impedance may be controlled simultaneously.
It should be noted that embodiments of the present invention are not limited to any specific combination of hardware and software. In the present patent application, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, the use of the verb "comprise a" to define an element does not exclude the presence of another, same element in a process, method, article, or apparatus that comprises the element. In the present patent application, if it is mentioned that a certain action is executed according to a certain element, it means that the action is executed according to at least the element, and two cases are included: performing the action based only on the element, and performing the action based on the element and other elements. The expression of a plurality of, a plurality of and the like includes 2, 2 and more than 2, more than 2 and more than 2.
All documents mentioned in this application are to be considered as being integrally included in the disclosure of this application so as to be subject to modification as necessary. Further, it is understood that various changes or modifications may be made to the present application by those skilled in the art after reading the above disclosure of the present application, and such equivalents are also within the scope of the present application as claimed.
Claims (10)
1. The control method of the flowing medium in the thermal ablation system is characterized in that the thermal ablation system comprises a radio frequency ablation probe, a pressure liquid nitrogen source and a heat exchange evaporation unit connected between the ablation probe and the pressure liquid nitrogen source, wherein the heat exchange evaporation unit is provided with a gas-liquid separator;
the control method comprises the following steps:
a, adjusting the rear end flow resistance of the gas-liquid separator to control the temperature of nitrogen flowing into the ablation probe to be kept within a preset temperature range;
b, detecting the head temperature of the ablation probe, and adjusting the rear-end flow resistance of the ablation probe according to the detected head temperature and the set radio frequency power so as to enable the head temperature to be the target temperature.
2. The control method according to claim 1, wherein the predetermined temperature range is-140 ℃ to-130 ℃, and the target temperature is between 0 ℃ and-40 ℃.
3. The control method according to claim 1, wherein step B further includes:
detecting the head temperature of the ablation probe, calculating the control voltage of a rear-end flow regulating device of the ablation probe by adopting a first formula and a second formula according to the detected head temperature, the set radio frequency power and the target temperature, and generating and outputting the control voltage to a control end of the flow regulating device at the rear end of the ablation probe so as to adjust the rear-end flow resistance of the ablation probe; wherein,
the first formula is:
the second formula is: error N ＝T-T set ；
Wherein, error N Temperature error at the present time, k P Is the power term proportionality coefficient, k T Is a temperature term scaling factor, T is the detected head temperature, P is the set RF power, T set And V is the control voltage of the rear end flow regulating device of the ablation probe.
4. The control method according to claim 1, wherein step a further includes:
detecting the nitrogen temperature of the ablation probe;
and when the detected nitrogen temperature is higher than a second threshold value, opening the flow regulating device at the rear end of the gas-liquid separator and/or increasing the voltage applied to the flow regulating device so as to control the temperature of the nitrogen flowing into the ablation probe to be kept within the preset temperature range between the first threshold value and the second threshold value.
5. The control method according to any one of claims 1 to 4, further comprising:
performing steps A to B in real time or periodically to maintain the head temperature at the target temperature.
6. The thermal ablation system is characterized by comprising a radio frequency ablation probe, a pressure liquid nitrogen source and a heat exchange evaporation unit connected between the ablation probe and the pressure liquid nitrogen source, wherein the heat exchange evaporation unit is provided with a gas-liquid separator;
the thermal ablation system further comprises:
a first flow resistance control unit configured to adjust a rear end flow resistance of the gas-liquid separator to control a temperature of nitrogen flowing into the ablation probe to be maintained within a predetermined temperature range;
the second flow resistance control unit is configured to detect the head temperature of the ablation probe and adjust the rear end flow resistance of the ablation probe according to the detected head temperature and the set radio frequency power so as to enable the head temperature to be a target temperature.
7. The thermal ablation system of claim 1, wherein the predetermined temperature range is-140 ℃ to-130 ℃ and the target temperature is between 0 ℃ and-40 ℃.
8. The thermal ablation system of claim 6, wherein the second flow resistance control unit includes a second temperature detection device, a second voltage adjustment module, and a second flow regulation device disposed at a rear end of the ablation probe;
the second temperature detection device is configured to detect a head temperature of the ablation probe;
the second voltage adjusting module is configured to calculate a control voltage of the second flow regulating device according to the detected head temperature of the ablation probe, the set radio frequency power and the target temperature by adopting a first formula and a second formula, and generate and output the control voltage to a control end of the first flow regulating device so as to adjust the rear end flow resistance of the ablation probe, wherein the first formula is
The second formula is error N ＝T-T set Wherein error r N For temperature error at the present moment, k P Is the power term proportionality coefficient, k T Is a temperature term proportionality coefficient, T is the detected head temperature, P is the set RF power, T set V is a control voltage of the second flow rate adjustment device for the target temperature.
9. The thermal ablation system of claim 6, wherein the first flow resistance control unit includes a first temperature detection device, a first voltage regulation module, and a first flow regulation device disposed at a rear end of the gas-liquid separator;
the temperature detection device is configured to detect a nitrogen temperature of the ablation probe;
the first voltage adjustment module is configured to turn off the first flow rate adjustment device or reduce a control voltage applied to the first flow rate adjustment device when the detected nitrogen temperature is less than a first threshold, and turn on the flow rate adjustment device at the rear end of the gas-liquid separator and/or increase the control voltage applied to the first flow rate adjustment device when the detected nitrogen temperature is greater than a second threshold, so as to control the temperature of nitrogen flowing into the ablation probe to be maintained within the predetermined temperature range between the first threshold and the second threshold.
10. The thermal ablation system of any one of claims 6-9, wherein the first flow resistance control unit and the second flow resistance control unit are alternately periodically executed to maintain the head temperature at the target temperature.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211229426.5A CN115530962A (en) | 2022-10-09 | 2022-10-09 | Thermal ablation system and method for controlling flowing medium in thermal ablation system |
| PCT/CN2022/131752 WO2024077704A1 (en) | 2022-10-09 | 2022-11-14 | Thermal ablation system and method for controlling flow medium in thermal ablation system |
| PCT/CN2023/123384 WO2024078415A1 (en) | 2022-10-09 | 2023-10-08 | Thermal ablation system, and method for controlling flowing medium in thermal ablation system |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202211229426.5A CN115530962A (en) | 2022-10-09 | 2022-10-09 | Thermal ablation system and method for controlling flowing medium in thermal ablation system |
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| WO (2) | WO2024077704A1 (en) |
Cited By (1)
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|---|---|---|---|---|
| WO2024078415A1 (en) * | 2022-10-09 | 2024-04-18 | 上海美杰医疗科技有限公司 | Thermal ablation system, and method for controlling flowing medium in thermal ablation system |
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| US6162217A (en) * | 1999-04-21 | 2000-12-19 | Oratec Interventions, Inc. | Method and apparatus for controlling a temperature-controlled probe |
| US7479139B2 (en) * | 2002-01-04 | 2009-01-20 | Galil Medical Ltd. | Apparatus and method for protecting tissues during cryoablation |
| CN100574719C (en) * | 2006-12-26 | 2009-12-30 | 上海导向医疗***有限公司 | Gas throttling cooling type radio frequency ablation electrode |
| WO2009090647A2 (en) * | 2008-01-15 | 2009-07-23 | Arbel Medical Ltd. | Cryosurgical instrument insulating system |
| EP2160990B1 (en) * | 2008-07-02 | 2015-11-04 | Erbe Elektromedizin GmbH | Supply device with control for operating a cryoprobe, cry-surgical device |
| US20220061902A1 (en) * | 2013-02-26 | 2022-03-03 | Cpsi Holdings Llc | Deployable assembly sleeve for ablation probe with deployable sensors |
| CN111839713B (en) * | 2019-04-24 | 2023-03-24 | 上海美杰医疗科技有限公司 | Multi-modal tumor ablation probe system and control method thereof |
| CN111012474A (en) * | 2019-09-17 | 2020-04-17 | 日照天一生物医疗科技有限公司 | Cryoablation needle and ablation system thereof |
| CN110934635A (en) * | 2019-12-04 | 2020-03-31 | 海杰亚（北京）医疗器械有限公司 | High-low temperature composite ablation operation system |
| CN212879546U (en) * | 2020-03-24 | 2021-04-06 | 海杰亚（北京）医疗器械有限公司 | Single working medium combined type ablation operation system |
| CN112263321B (en) * | 2020-06-23 | 2022-04-01 | 上海微创电生理医疗科技股份有限公司 | Cryoablation temperature control method, system and medium |
| CN115089286A (en) * | 2021-11-08 | 2022-09-23 | 海杰亚（北京）医疗器械有限公司 | Cryoablation temperature control method and device and cryosurgery system |
| CN115530962A (en) * | 2022-10-09 | 2022-12-30 | 上海美杰医疗科技有限公司 | Thermal ablation system and method for controlling flowing medium in thermal ablation system |
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2022
- 2022-10-09 CN CN202211229426.5A patent/CN115530962A/en active Pending
- 2022-11-14 WO PCT/CN2022/131752 patent/WO2024077704A1/en unknown
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024078415A1 (en) * | 2022-10-09 | 2024-04-18 | 上海美杰医疗科技有限公司 | Thermal ablation system, and method for controlling flowing medium in thermal ablation system |
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