CN114681042A - Radio frequency ablation measurement and control system - Google Patents

Radio frequency ablation measurement and control system Download PDF

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CN114681042A
CN114681042A CN202011583160.5A CN202011583160A CN114681042A CN 114681042 A CN114681042 A CN 114681042A CN 202011583160 A CN202011583160 A CN 202011583160A CN 114681042 A CN114681042 A CN 114681042A
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radio frequency
temperature
voltage
current
output
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邹金成
邹柯
王逸飞
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Shanghai Meijie Medical Technology Co ltd
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Shanghai Meijie Medical Technology Co ltd
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/04—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
    • A61B18/12—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00636—Sensing and controlling the application of energy
    • A61B2018/00642—Sensing and controlling the application of energy with feedback, i.e. closed loop control
    • A61B2018/00648—Sensing and controlling the application of energy with feedback, i.e. closed loop control using more than one sensed parameter
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00636—Sensing and controlling the application of energy
    • A61B2018/00696—Controlled or regulated parameters
    • A61B2018/00702—Power or energy
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00636—Sensing and controlling the application of energy
    • A61B2018/00696—Controlled or regulated parameters
    • A61B2018/00767—Voltage
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00636—Sensing and controlling the application of energy
    • A61B2018/00773—Sensed parameters
    • A61B2018/00791—Temperature
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00636—Sensing and controlling the application of energy
    • A61B2018/00773—Sensed parameters
    • A61B2018/00791—Temperature
    • A61B2018/00821—Temperature measured by a thermocouple
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00636—Sensing and controlling the application of energy
    • A61B2018/00773—Sensed parameters
    • A61B2018/00827—Current
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00636—Sensing and controlling the application of energy
    • A61B2018/00773—Sensed parameters
    • A61B2018/00875—Resistance or impedance
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00636—Sensing and controlling the application of energy
    • A61B2018/00773—Sensed parameters
    • A61B2018/00892—Voltage

Abstract

The application relates to the field of biomedical engineering and discloses a radio frequency ablation measurement and control system. The system comprises a linearized voltage acquisition circuit, a voltage calibration module and an output module, wherein the linearized voltage acquisition circuit acquires current radio frequency detection voltage, the voltage calibration module detects current ablation tissue impedance by taking rated impedance as a reference, the radio frequency output voltage is corrected according to the current radio frequency detection voltage and the current ablation tissue impedance, and the output module outputs radio frequency signals according to the corrected radio frequency output voltage so as to heat the current ablation tissue. The radio frequency ablation measurement and control system can rapidly and accurately control the output radio frequency ablation energy, protect normal tissues from being damaged and improve the cure rate.

Description

Radio frequency ablation measurement and control system
Technical Field
The application relates to the field of biomedical engineering, in particular to a radio frequency ablation measurement and control technology.
Background
The incidence of malignant tumor, atherosclerosis, arrhythmia, benign prostatic hyperplasia, arteriovenous malformation and the like is increased year by year, the threat to human health is more and more serious, although the traditional treatment methods such as surgical operation, radiotherapy, chemotherapy and the like are mature day by day in the treatment process, the methods inevitably cause damage to the normal functions of the organism to different degrees, and the treatment success rate is still required to be improved.
With the development of science and technology, in particular the progress of medical imaging technology such as nuclear magnetic resonance imaging and ultrasonic imaging, the minimally invasive treatment operations such as thermal physical therapy and the like have been developed greatly and are more and more popular. However, the method still has the defects that the accurate treatment of the focal tissues is difficult to realize.
The radiofrequency ablation utilizes a high-frequency current field to heat and treat focal tissues, has low cost and is easy to control and widely applied to treatment of diseases such as atherosclerosis, tumors, arrhythmia and the like compared with microwave and laser ablation, but the radiofrequency ablation treatment in the market is only limited to burning off the focal, damaging normal tissues, has high recurrence rate and is difficult to realize long-term and effective treatment at one time.
The multi-modal tumor radio-frequency treatment method is characterized in that after pre-freezing is carried out, precise radio-frequency heating treatment is carried out, the defects of conventional freezing or thermal treatment are overcome, the cure rate can be improved, and the method becomes a hot point of precise thermal physical treatment. Animal experiments show that the antigen can be promoted to be released and effectively presented by accurately controlling the thermotherapy temperature around tumor cells, and researches show that the immune system can be started under a specific temperature environment to stimulate the expression and presentation of immune factors. And the effective treatment of atherosclerosis needs to be fully opened to block the blood vessel, ensure smooth blood flow, effectively protect endothelial cells as far as possible, inhibit smooth muscle cell proliferation and prevent restenosis, and the unique action of thermophysics on biological tissues needs to be utilized to accurately control the thermal physical energy to control the center of the plaque to form high-temperature ablation and simultaneously protect the endothelial cells, so that the occurrence of restenosis is reduced as far as possible, and long-term effective treatment is achieved.
Disclosure of Invention
The application aims to provide a radio frequency ablation measurement and control system which can rapidly and accurately control output radio frequency ablation energy, protect normal tissues from being damaged and improve the cure rate.
The application discloses radio frequency melts system of observing and controling includes:
the linear voltage acquisition circuit is used for acquiring the current radio frequency detection voltage;
the voltage calibration module is used for detecting the current impedance of the ablation tissue by taking the rated impedance as a reference, and correcting the radio frequency output voltage according to the current radio frequency detection voltage and the current impedance of the ablation tissue;
and the output module is used for outputting a radio frequency signal according to the corrected radio frequency output voltage so as to heat the current ablation tissue.
In a preferred embodiment, the voltage calibration module is further configured to apply a formula according to the current rf detection voltage and the current ablated tissue impedance
Figure BDA0002866366500000021
Correcting the radio frequency output voltage, wherein Z represents the current ablation tissue impedance, a, b, c and d respectively represent correction coefficients which are constants, and UcRepresenting the current rf detection voltage.
In a preferred embodiment, the voltage calibration module is further configured to: carrying out linear calibration on the current radio frequency detection voltage in advance under rated impedance to obtain a calibration equation; based on the current ablation tissue impedance Z, a correction formula is adopted
Figure BDA0002866366500000022
Correcting the first-order coefficient k of the calibration equation to obtain a corrected calibration equation; and detecting the voltage U according to the current radio frequencycCalculating the corrected radio frequency output voltage based on the corrected calibration equation.
In a preferred embodiment, the voltage calibration module is further configured to: performing linear calibration on the radio frequency detection voltages under n groups of different load impedances, and solving a first-order coefficient k of the calibration equation under each group of load impedances1,k2,k3,…,kn(ii) a Based on the solved k1,k2,k3,…,knAnd calculating the correction coefficients a, b, c and d by adopting a data fitting mode.
In a preferred embodiment, the voltage calibration module is further configured to iteratively perform the following steps until a preset condition is met: and calculating the current ablation tissue impedance according to the corrected radio frequency output voltage, and correcting the corrected radio frequency output voltage according to the calculated current ablation tissue impedance.
In a preferred embodiment, the preset conditions are: and reaching a preset iteration time, or enabling the difference value of the corrected radio frequency output voltage of the two iterations to be smaller than a preset threshold value.
In a preferred embodiment, the system further comprises a linearization temperature acquisition circuit for acquiring the current detection temperature;
the system also comprises a temperature calibration module for calibrating the current output temperature by adopting a hot environment temperature and cold environment temperature correction compensation algorithm and a machine autonomous learning correction algorithm based on the target temperature and the current detection temperature.
In a preferred embodiment, the system further comprises a temperature control module for controlling the temperature of the output shaft based on the actual output temperature and the target output temperature according to a control equation
Figure BDA0002866366500000031
Figure BDA0002866366500000032
Precise and rapid output of control temperature, where kpIs a proportional term, kiAs integral term, kdA derivative term, S (n) is a temperature control amount, and Δ T ═ Ts-T0，T0To actually output the temperature, TsIs the target output temperature.
In a preferred embodiment, the system further comprises a power control module for controlling the power of the output power of the power converter based on the actual output power and the target output power according to the formula
Figure BDA0002866366500000033
Controlling the accurate and fast output of power, wherein PsIs the target output power, P0In order to actually output the power,
Figure BDA0002866366500000034
ΔP＝Ps-P0in order to be able to measure the power error,
Figure BDA0002866366500000035
U0、I0respectively, the calibrated rf voltage and current.
In a preferred embodiment, the system further comprises a low-radiation interference radio frequency temperature integrated transmission line for parallel transmission of radio frequency signals and temperature signals, and the transmission line uses an insulation design of a radiation interference resistant material on a metal outer layer.
Compared with the prior art, the embodiment of the application at least comprises the following advantages and effects:
the method comprises the steps of collecting radio frequency output voltage in the radio frequency treatment process, processing collected parameters by adopting a linear processing circuit, detecting current ablation tissue impedance by taking rated impedance as a reference for the processed parameters, and correcting the radio frequency output voltage according to the current radio frequency detection voltage and the current ablation tissue impedance, so that precise control of radio frequency output signals is realized, the radio frequency signals are accurately applied to target tissues, precise treatment and precise control of radio frequency ablation are realized, normal tissues are protected from being damaged, the cure rate is improved, and even long-term effective treatment of tumors and atherosclerosis is expected to be realized.
And carrying out multiple iterative corrections on the radio frequency output voltage, and further improving the precision of the radio frequency output signal.
The radio frequency and temperature integrated transmission line with the radiation interference resistance is adopted in the radio frequency signal transmission, the radio frequency output voltage, the radio frequency current and the radio frequency temperature are collected at the same time, the linearization processing is used, the temperature calibration algorithm, the radio frequency voltage calibration algorithm, the power control algorithm and the temperature control algorithm are designed on the basis of the circuit linearization processing, the precision of the radio frequency output signal is improved, the accurate and quick response of the output radio frequency signal is realized, the cure rate is further improved, the normal tissue is protected from being damaged, and even the long-term effective treatment of the tumor and the atherosclerosis is expected to be realized.
The present specification describes a number of technical features distributed throughout the various technical aspects, and if all possible combinations of technical features (i.e. technical aspects) of the present specification are listed, the description is made excessively long. 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, the feature a + B + C is disclosed, in another example, the feature a + B + D + E is disclosed, and the features C and D are equivalent technical means for the same purpose, and technically only one feature is used, but not simultaneously employed, and the feature E can be technically combined with the feature C, then the solution of a + B + C + D should not be considered as being described because the technology is not feasible, and the solution of a + B + C + E should be considered as being described.
Drawings
Fig. 1 is a block diagram of a radio frequency ablation measurement and control system according to a first embodiment of the present application.
FIG. 2 is a block diagram of an example acquisition unit structure according to the present application.
Fig. 3a is a circuit diagram of a radio frequency output network according to the present application.
Fig. 3b is an equivalent impedance network circuit diagram of a radio frequency output network according to the present application.
Fig. 4 is a flow chart of a precise fast temperature control process according to the present application.
Fig. 5 is a flow chart of a precise fast power control procedure according to the application.
Fig. 6 is a block diagram of an example rf ablation measurement and control system configuration according to the present application.
Fig. 7 is a control graph of an example power control according to the present application.
FIG. 8 is a control graph of an example temperature control according to the present application.
FIG. 9 is a graph of the effects of an example temperature control according to the present application.
Wherein the content of the first and second substances,
11-radio frequency temperature integrated transmission line 12-linear voltage acquisition circuit
13-linearized temperature acquisition circuit 14-voltage calibration module
15-temperature calibration module 16-power control module
17-temperature control module 18-output module
121-radio frequency output isolation circuit 122-thermocouple temperature acquisition circuit
123-thermocouple temperature compensation and correction circuit 124-thermocouple signal amplification circuit
125-radio frequency current isolation coupling circuit 126-radio frequency voltage compensation correction circuit
127-radio frequency voltage acquisition processing circuit 128-radio frequency current sampling compensation circuit
129-linear optical coupling isolation circuit 221-small signal trial voltage generation module
222-fast power control algorithm 223-probing the rf output power
224-target power 225-actual power output
231-target temperature 232-temperature control algorithm
233 algorithm output control parameter 234 control radio frequency power output
235-target temperature output
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 rf ablation measurement and control system, which is configured as shown in fig. 1 and includes a linearized voltage acquisition circuit 12, a voltage calibration module 14, and an output module 18.
The linearized voltage acquisition circuit 12 is used to acquire the current radio frequency detection voltage. Specifically, the linearized voltage acquisition circuit 12 detects the radio frequency detection voltage, and linearizes the detected radio frequency detection voltage to obtain the current radio frequency detection voltage.
Optionally, the system further comprises a linearized temperature acquisition circuit 13 for acquiring the current detected temperature. The linearized temperature acquisition circuit 13 is configured to detect one or more sets of temperature signals.
Optionally, the system further comprises a low radiation interference radio frequency temperature integrated transmission line 11 as a transmission line between the radio frequency treatment probe and the acquisition circuit, the transmission line uses an insulation design of a radiation interference resistant material on a metal outer layer, during the radio frequency ablation, the radio frequency signal is accurately transmitted to the currently ablated tissue through the integrated transmission line 11, and the standard temperature signal monitored by a thermocouple arranged at the radio frequency treatment probe is transmitted to the linearization temperature acquisition circuit 13 through the integrated transmission line 11.
Fig. 2 is a schematic structural diagram of an exemplary acquisition unit, which mainly includes a linearized voltage acquisition circuit, a current acquisition circuit, and a linearized temperature acquisition circuit, as shown in fig. 2. The example acquisition unit mainly outputs acquired radio frequency voltage, current and temperature data to the control unit 2 for processing after linear processing, compensation correction processing and optical coupling isolation; specifically, in the working process, the radio frequency output isolation circuit 121 isolates the collected signal from the radio frequency output signal, so as to avoid mutual interference between the collection circuit and the radio frequency output, in the radio frequency voltage collection process, the radio frequency voltage collection and processing circuit 127 linearly processes the effective value of the radio frequency voltage, converts the effective value into a direct current signal (for example, a 0-5V direct current voltage signal) and inputs the direct current signal to the AD end of the control system through the linear optocoupler isolation circuit 129, and in the radio frequency voltage collection and processing process, the radio frequency voltage compensation and correction circuit 126 is used to correct the real-time voltage and ensure the linearization of the output signal; in the current signal collection process, firstly, the radio frequency current is linearly converted into a radio frequency voltage value through the radio frequency current coupling isolation circuit 125, then the radio frequency voltage value is converted into an output linear voltage (for example, 0-5V) through the radio frequency current collection processing circuit 128, the output linear voltage is output to the AD end of the control system through the linear isolation circuit, and in the radio frequency current collection process, the compensation correction circuit 126 is added for circuit correction and compensation; in the process of acquiring the temperature signals, the high-speed thermocouple temperature acquisition circuit 122 is used for acquiring and processing the thermocouple signals, the thermocouple temperature compensation and correction circuit 123 is used for correcting and compensating the circuits in the acquisition process to ensure the accuracy of the acquisition circuits, and then the high-precision thermocouple signal amplification circuit 124 is used for amplifying the acquired thermocouple signals and transmitting the signals to the AD port of the control system 2 through the linear isolation circuit for acquisition and processing. The control unit 2 may include, for example, the aforementioned voltage calibration module 14, a temperature calibration module 15 to be described later, a power control module 16, a temperature control module 17, and the like.
Further, the voltage calibration module 14 is configured to detect a current ablated tissue impedance with reference to a rated impedance, and correct the rf output voltage according to the current rf detection voltage and the current ablated tissue impedance; and the output module 18 is used for outputting a radio frequency signal according to the corrected radio frequency output voltage so as to heat the current ablation tissue.
Optionally, the voltage calibration module 14 is further configured to apply a formula according to the current RF detection voltage and the current ablated tissue impedance
Figure BDA0002866366500000081
Correcting the RF output voltage, wherein Z represents the current ablated tissue impedance, a, b, c, d represent correction coefficients, UcRepresenting the current rf detection voltage.
Optionally, the voltage calibration module 14 is further configured to: the current radio frequency detection voltage is subjected to linear calibration in advance under the rated impedance to obtain a calibration equation UE＝kUc+ x, wherein UcRepresenting the current RF detection voltage under rated impedance, k representing the first order coefficient, x being a constant, UERepresenting the radio frequency output voltage at the rated impedance; based on the current ablation tissue impedance Z detected by taking the rated impedance as the reference, a correction formula is adopted
Figure BDA0002866366500000082
Correcting the first-order coefficient k to obtain a corrected calibration equation UE＝(k+Δk)Uc+ x; and detecting the voltage U according to the current radio frequencycThe modified rf output voltage is calculated based on the modified calibration equation.
The correction coefficients a, b, c, and d are obtained by pre-calculating, for example, by performing linear calibration on the rf detection voltages under n groups of different load impedances, and solving a first order coefficient k of the calibration equation under each group of load impedances1,k2,k3,…,kn(ii) a Based on the solved k1,k2,k3,…,knThe correction coefficients a, b, c, d are calculated by data fitting. Such as, but not limited to, a least squares data fitting.
Optionally, a correction formula
Figure BDA0002866366500000083
Calculated by the following method: analyzing the RF output circuit to obtain equivalent impedance network, analyzing the network transfer function to obtain impedance correction relation, and obtaining correction formula
Figure BDA0002866366500000084
Specifically, the RF output network is shown in FIG. 3a, and the equivalent impedance network is shown in FIG. 3b, where U1For measuring and controlling the radio-frequency detection voltage, U2For the radio frequency output voltage, Z1Is a load equivalent impedance, Z2Is the input impedance of the transformer, Z3To sample the line impedance. According to the equivalent circuit of fig. 3b, the network function relationship of the signal transmission can be obtained as follows:
Figure BDA0002866366500000085
since the detected impedance is Z1Where Z is the actual impedance and Δ Z is the line deviation impedance, which is substituted into transfer function (1), the relationship can be found as
Figure BDA0002866366500000091
The deviation impedance DeltaZ in the same circuit is a constant value, and Z2、Z3Is constant, so a ═ Z can be defined2，b＝ΔZ×Z2，c＝Z2+Z3，d＝ΔZ(Z2+Z3)+Z2×Z3
Bringing it into relation (2) to obtain
Figure BDA0002866366500000092
Normalizing the radio frequency detection voltage of the rated impedance by taking the rated impedance as a standard, wherein the error relation between the radio frequency output voltage and the radio frequency detection voltage meets a relational expression (3), and then obtaining the radio frequency detection voltage
Figure BDA0002866366500000093
Optionally, the voltage calibration module 14 is further configured to iteratively perform the following steps until a preset condition is met: and calculating the current ablation tissue impedance according to the corrected radio frequency output voltage, and correcting the corrected radio frequency output voltage according to the calculated current ablation tissue impedance. Wherein the preset condition is, for example, but not limited to, a group of the following: firstly, reaching a preset iteration frequency; and the difference value of the corrected radio frequency output voltage of the two iterations is smaller than a preset threshold value.
The system further comprises a temperature calibration module 15, the temperature calibration module 15 being configured to calibrate the current output temperature using a hot and cold ambient temperature correction compensation algorithm and a machine-independent learning correction algorithm based on the target temperature and the current detected temperature. Specifically, N superfine standard thermocouples are integrated on one point of a radio frequency probe in advance, one of the N superfine standard thermocouples is connected to a standard temperature detector, the other N-1 thermocouples are connected to the system and used for collecting standard temperature data in real time, and the standard temperature detector is communicated with the system; compiling a polynomial fitting algorithm and a machine automatic calibration correction algorithm in advance; in the calibration process, a standard thermocouple is placed in a water bath with temperature change at the same time, the system autonomously acquires N-1 paths of real-time temperature data, one path of temperature data detected by a standard temperature detector is used for calibrating the N-1 paths of temperature data, a machine automatic correction algorithm is adopted for learning the temperature data, and a polynomial coefficient is solved according to the machine correction data by adopting a least square algorithm; the real-time temperature is calibrated according to a pre-programmed polynomial fitting algorithm.
Optionally, the system further comprises a temperature control module 17, the temperature control module 17 being configured to control the temperature based on the actual output temperature and the target output temperature according to a control equation
Figure BDA0002866366500000101
Figure BDA0002866366500000102
Precise and rapid output of control temperature, where kpIs a proportional term, kiAs integral term, kdA derivative term, S (n) is a temperature control amount, and Δ T ═ Ts-T0，T0To actually output the temperature, TsIs the target output temperature. Specifically, as shown in fig. 4, which is a flow chart of accurate and fast temperature control, when temperature control is performed, the temperature control module 17 takes the target temperature 231 and the real-time acquisition temperature 235 as inputs of the fast temperature control algorithm 232, and outputs the real-time rf power control signal 233 to control the rf energy output 234 after the calculation processing of the fast temperature control algorithm 232, so as to control the rf to perform rf heating on tissue quickly, and finally, quickly, the error between the real-time temperature 235 and the target temperature 231 is smaller than 0.15 ℃, and the system can complete 20 to 100 ℃ fast heating within 10sHeat quickly and stabilize the temperature. The rapid temperature control algorithm mainly adopts a typical PID control method, the control equation is obtained after the algorithm adopts accurate timing control and real-time normalization, and k is separated according to the set temperature response rate and the set temperature valuepAction time and adjustment kpValue, while adaptively adjusting kiAnd kdThe value of (c) is obtained, so that a reasonable temperature control quantity S (n) is obtained, and the real-time and accurate output and quick response of the temperature are controlled.
Optionally, the system further comprises a power control module 16 for controlling the power of the power converter based on the actual output power and the target output power according to a formula
Figure BDA0002866366500000103
Controlling the accurate and fast output of power, wherein PsIs the target output power, P0In order to actually output the power of the power,
Figure BDA0002866366500000104
ΔP＝Ps-P0in order to be able to measure the power error,
Figure BDA0002866366500000105
U0、I0respectively, the calibrated rf voltage and current. Specifically, as shown in fig. 5, which is a flow chart of an accurate and fast power control process, when performing power control, firstly, a small-signal trial voltage 221 is used, a trial power 223 is calculated primarily by a fast power control algorithm 222, and a first step of control is performed to feed back an error between the trial power and a target power to the fast control algorithm 222 for control output to obtain an actual output power 225, and then the actual output power is fed back to an input end of the fast control algorithm for power control with a circular negative feedback. The control time of the first step trial power control process is less than 3ms, and the whole stable target power control output time is less than 40 ms. Obtaining radio frequency voltage and radio frequency current after accurate calibration, calculating real-time radio frequency power, analyzing the variation of the real-time power and power error, establishing an error mathematical model, carrying out Taylor expansion on the error mathematical model, and reserving the Taylor expansionCalculating at least two terms of the Leehrlan series, using a precise timing control algorithm, precisely controlling time output power, and controlling rapid and precise output of power, wherein the mathematical relationship of the rapid power control algorithm is established and realized as follows: according to power calculation formula
Figure BDA0002866366500000111
Available voltage-power relationship
Figure BDA0002866366500000112
Due to the actual power P1＝Ps- Δ P, wherein PsFor the target power, Δ P is the power error, so the actual output voltage is
Figure BDA0002866366500000113
Due to the fact that
Figure BDA0002866366500000114
Very small, in addition
Figure BDA0002866366500000115
The Taylor expansion is as follows:
Figure BDA0002866366500000116
the control signal DA and the actual output voltage are in a linear relation, and then the actual output control signal DA is obtained as kU.
Fig. 6 is a block diagram of an exemplary rf ablation measurement and control system, which includes an acquisition unit, a calibration unit, a control unit, an output unit, and an rf therapy probe. The acquisition unit may comprise, for example, a linearized voltage acquisition circuit 12 and a linearized temperature acquisition circuit 13 in fig. 1; the calibration unit may for example comprise the voltage calibration module 14 and the temperature calibration module 15 of fig. 1; the control unit may include, for example, the power control module 16 and the temperature control module 17 of fig. 1; the output unit may comprise, for example, the output module 18 of fig. 1.
In order to better understand the technical solution of the present application, the following description is made with reference to a specific test example, and the details listed in the example are mainly for understanding and are not intended to limit the scope of the present application.
In this test example, the above-mentioned rapid and accurate rf ablation measurement and control system was tested in combination with an rf generation system, and the rf generation system described herein is a small digital cold and hot alternative therapeutic apparatus, chinese patent application publication No. CN106137378A, and an rf ablation signal generation and control circuit with selectable frequency, chinese utility model patent publication No. CN 208989123U.
During the test, the treatment electrodes were inserted into the bio-gel of 15 × 10cm size, and the neutral electrode plate for rf ablation was placed at the bottom of the bio-gel, and rf ablation signals were applied to the multi-modal tumor rf treatment probe, and the actual output powers when heated at 5W, 10W, 20W, 30W, 40W, 50W, and 60W powers were tested as shown in fig. 7.
The above-mentioned colloids were subjected to rapid temperature rise control at 50 ℃, 60 ℃, 70 ℃, 80 ℃, 90 ℃ and 95 ℃ under the same conditions, and the control curves thereof are shown in FIG. 8.
The temperature control experiment of the system on the isolated pork liver is carried out, the temperature control error is less than 0.5 ℃ when the temperature is controlled to be constant at 95 ℃, and the control curve is shown in figure 9.
From the experimental data of the test example, the radio frequency ablation measurement and control system disclosed by the invention realizes the accurate control and the quick response of the radio frequency power and the temperature in the radio frequency treatment, provides a premise for realizing an accurate radio frequency treatment control algorithm, and can target the precise action of the radio frequency treatment energy to tissues to achieve the aim of the accurate radio frequency treatment.
It is noted that, in the present patent application, relational terms such as first and second, and the like are 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 incorporated in their entirety into the disclosure of this application so as to be subject to modification as necessary. It should be understood that the above description is only a preferred embodiment of the present disclosure, and is not intended to limit the scope of the present disclosure. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of one or more embodiments of the present disclosure should be included in the scope of protection of one or more embodiments of the present disclosure.

Claims (10)

1. A radio frequency ablation measurement and control system, comprising:
the linear voltage acquisition circuit is used for acquiring the current radio frequency detection voltage;
the voltage calibration module is used for detecting the current impedance of the ablation tissue by taking the rated impedance as a reference, and correcting the radio frequency output voltage according to the current radio frequency detection voltage and the current impedance of the ablation tissue;
and the output module is used for outputting a radio frequency signal according to the corrected radio frequency output voltage so as to heat the current ablation tissue.
2. The radio frequency of claim 1The ablation measurement and control system is characterized in that the voltage calibration module is further used for adopting a formula according to the current radio frequency detection voltage and the current ablation tissue impedance
Figure FDA0002866366490000011
Correcting the radio frequency output voltage, wherein Z represents the current ablation tissue impedance, a, b, c and d respectively represent correction coefficients which are constant, and UcRepresenting the current rf detection voltage.
3. The rf ablation measurement and control system of claim 2, wherein the voltage calibration module is further configured to: carrying out linear calibration on the current radio frequency detection voltage in advance under rated impedance to obtain a calibration equation; based on the current ablation tissue impedance Z, a correction formula is adopted
Figure FDA0002866366490000012
Correcting the first-order coefficient k of the calibration equation to obtain a corrected calibration equation; and detecting the voltage U according to the current radio frequencycCalculating the corrected radio frequency output voltage based on the corrected calibration equation.
4. The rf ablation measurement and control system of claim 3, wherein the voltage calibration module is further configured to: performing linear calibration on the radio frequency detection voltages under n groups of different load impedances, and solving a first-order coefficient k of the calibration equation under each group of load impedances1，k2，k3，...，kn(ii) a Based on the solved k1，k2，k3，...，knAnd calculating the correction coefficients a, b, c and d by adopting a data fitting mode.
5. The rf ablation measurement and control system of claim 1, wherein the voltage calibration module is further configured to iteratively perform the following steps until a predetermined condition is met: calculating the current ablation tissue impedance according to the corrected radio frequency output voltage, and correcting the corrected radio frequency output voltage according to the calculated current ablation tissue impedance.
6. The rf ablation measurement and control system of claim 2, wherein the predetermined conditions are: and reaching a preset iteration time, or enabling the difference value of the corrected radio frequency output voltage of the two iterations to be smaller than a preset threshold value.
7. The rf ablation measurement and control system of claim 1, further comprising a linearized temperature acquisition circuit for acquiring a current detected temperature;
the system also comprises a temperature calibration module for calibrating the current output temperature by adopting a hot environment temperature and cold environment temperature correction compensation algorithm and a machine autonomous learning correction algorithm based on the target temperature and the current detection temperature.
8. The rf ablation measurement and control system of claim 7, further comprising a temperature control module for controlling the temperature of the target output temperature based on the actual output temperature and a target output temperature according to a control equation
Figure FDA0002866366490000021
Figure FDA0002866366490000022
Precise and rapid output of control temperature, where kpIs a proportional term, kiAs integral term, kdA derivative term, S (n) is a temperature control amount, and Δ T ═ Ts-T0，T0To actually output the temperature, TsIs the target output temperature.
9. The rf ablation measurement and control system of claim 8, further comprising a power control module for controlling the rf ablation measurement and control system based on the actual output power and the target output power according to a formula
Figure FDA0002866366490000023
Figure FDA0002866366490000024
Controlling the accurate and fast output of power, wherein PsTo target output power, P0 is actual output power,
Figure FDA0002866366490000025
ΔP＝Ps-P0in order to be able to measure the power error,
Figure FDA0002866366490000026
U0、I0respectively, the calibrated rf voltage and current.
10. The rf ablation measurement and control system according to any of claims 1-9, further comprising a low-radiation interference rf-temperature integrated transmission line for parallel transmission of rf signals and temperature signals, wherein the transmission line uses an insulation design of a radiation interference resistant material on the outer metal layer.
CN202011583160.5A 2020-12-28 2020-12-28 Radio frequency ablation measurement and control system Pending CN114681042A (en)

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