CN114129255A

CN114129255A - Impedance detection device and radio frequency ablation system of living body

Info

Publication number: CN114129255A
Application number: CN202010918869.XA
Authority: CN
Inventors: 刘道洋; 王雄志; 胡善锋; 丘信炯
Original assignee: Hangzhou Nuo Cheng Medical Instrument Co ltd
Current assignee: Hangzhou Nuo Cheng Medical Instrument Co ltd
Priority date: 2020-09-03
Filing date: 2020-09-03
Publication date: 2022-03-04

Abstract

The application provides an impedance detection device and a radio frequency ablation system of a living body. The detection device comprises an excitation signal generation unit, a transmission unit, an impedance signal acquisition unit and a processing unit. The excitation signal generation unit generates and outputs a high-frequency excitation signal. The transmission unit transmits the high-frequency excitation signal to a detection site on the living body through an output end thereof, wherein the output end of the transmission unit constitutes an impedance signal detection point. The impedance signal acquisition unit is electrically connected with the impedance signal detection point and is used for acquiring a sampling signal from the impedance signal detection point in real time. The processing unit is electrically connected with the impedance signal acquisition unit and is used for acquiring the sampling signal and determining a real-time impedance value of the organism corresponding to a real-time sampling value of the sampling signal according to a preset impedance calibration data table. The impedance detection device of the organism can accurately and quickly detect the real-time impedance value of the organism in the treatment process so as to monitor the change of the impedance of the organism in real time in the treatment process.

Description

Impedance detection device and radio frequency ablation system for living body

Technical Field

The application relates to the technical field of impedance detection, in particular to an impedance detection device and a radio frequency ablation system of an organism.

Background

The ablation operation is to deliver energy such as radio frequency, microwave, freezing, laser and the like to target tissues for ablation under the guidance of images, has the characteristic of minimally invasive, and is applied to clinical treatment of tumor diseases, nerve diseases and heart diseases such as hypertrophic cardiomyopathy and the like.

The impedance of a living body, such as a human body, is an important electrophysiological signal, and during an ablation treatment, the impedance of the living body changes continuously as the ablation treatment progresses. However, if the impedance of the living body changes at too fast a rate or the impedance value is too high, there is a risk that ablation will be excessive, resulting in carbonization of the tissue in the target region. Therefore, real-time detection of the impedance of the living body is very necessary to ensure the self-safety of the patient and the effect of the ablation treatment. Some existing schemes for detecting the impedance of the organism have the defects of complex scheme and slow dynamic response, and are not suitable for detecting the impedance of the organism in real time and rapidly in the ablation surgical process.

Disclosure of Invention

The application provides an impedance detection device and a radio frequency ablation system of a biological body, which can detect the impedance of the biological body in real time in the treatment process, have high response speed and simple structure, and can monitor the impedance change of the biological body in real time in the treatment process, thereby ensuring the safe treatment.

A first aspect of the present application provides an impedance detection apparatus of a living organism, including an excitation signal generation unit, a transmission unit, an impedance signal acquisition unit, and a processing unit. The excitation signal generating unit is used for generating and outputting a high-frequency excitation signal. The transmission unit comprises a first transmission end and a second transmission end, the transmission unit is electrically connected with the excitation signal generation unit through the first transmission end to receive the high-frequency excitation signal, and transmits the high-frequency excitation signal to a detection part on the organism through the second transmission end, wherein the second transmission end forms an impedance signal detection point. The impedance signal acquisition unit is electrically connected with the impedance signal detection point and is used for acquiring a sampling signal from the impedance signal detection point in real time. The processing unit is electrically connected with the impedance signal acquisition unit and is used for acquiring the sampling signal and determining a biological real-time impedance value corresponding to a real-time sampling value of the sampling signal according to a preset impedance calibration data table, wherein the impedance calibration data table records mapping relations between a plurality of biological analog impedance values and sampling values of a plurality of sampling signals in advance.

A second aspect of the application provides a radio frequency ablation system comprising a radio frequency energy generation unit, an ablation device and an impedance detection device of a living being as described above. The radio frequency energy generating unit is used for providing radio frequency energy required by radio frequency ablation. The ablation device is electrically connected with the radio frequency energy generation unit and is used for being inserted into a treatment part of an organism during radio frequency ablation, receiving the radio frequency energy output by the radio frequency energy generation unit and releasing the radio frequency energy to the treatment part so as to perform radio frequency ablation on the treatment part.

The utility model provides an impedance detection device of organism, according to the impedance value of organism and the characteristic that sampling value of sampling signal becomes approximate linear relation in certain extent, through preset the real-time impedance value of organism is confirmed to the impedance calibration data table, and the response is fast, can detect out the real-time impedance value of organism accurately, fast to can be at the change of treatment in-process real time monitoring organism impedance, provide reference information for medical personnel, and then ensure that the safety of treatment goes on.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a schematic structural view of an impedance detection device for a living body according to an embodiment of the present invention.

Fig. 2 is a schematic diagram of an impedance loop according to an embodiment of the present disclosure.

Fig. 3 is a schematic circuit diagram of the excitation signal generating unit and the transmission unit in fig. 1.

Fig. 4 is a schematic diagram of a waveform transformation process of the excitation signal generation unit of fig. 3.

Fig. 5 is a schematic circuit structure diagram of the impedance signal acquisition unit in fig. 1.

Fig. 6 is a circuit configuration diagram of the operational amplifier unit in fig. 1.

Fig. 7 is an equivalent circuit diagram of the impedance loop of the present application.

Fig. 8 is a graph showing a relationship between a voltage value of a sampling signal and a biological impedance value according to the present invention.

Fig. 9 is a schematic diagram of an impedance calibration data table according to an embodiment of the present application.

Fig. 10 is a flowchart of a method for detecting impedance of a living body according to an embodiment of the present application.

Fig. 11 is a flowchart of another method for detecting impedance of a living body according to the embodiment of the present application.

Fig. 12 is a schematic structural diagram of a radio frequency ablation system according to an embodiment of the present application.

Description of the main elements

Impedance detection device 100 for living body

Excitation signal generating unit 31

First input terminal 311

First output terminal 312

Waveform conversion circuit 313

Transmission unit 32

First transmission end 321

A second transmission terminal, an impedance signal detecting point 322

Impedance signal acquisition unit 33

Second input terminal 331

Second output terminal 332

Anti-jamming circuit 333

Operational amplification unit 34

Third input terminal 341

Third output terminal 342

Filter circuit 343

Operational amplifier circuit 344

Processing unit 35

Data acquisition module 351

Calculation Module 352

Neutral electrode 41

Memory 42

Capacitances C1, C2, C3, C4, C7, C8, C9, C10

Resistors R1, R2, R3, R5 and R6

Inductances L1, L2, L3

Operational amplifiers AR1, AR2, AR3

Biological object 200

Detection site 21

Radiofrequency ablation system 1000

Radio frequency energy generating unit 500

Ablation device 600

Steps

1001 and 1002, 1101 and 1106

The following detailed description will further illustrate the present application in conjunction with the above-described figures.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. The drawings are for illustration purposes only and are merely schematic representations, not intended to limit the present application. It is to be understood that the embodiments described are only a few examples of the present application and not all examples. All other embodiments obtained by a person of ordinary skill in the art without any inventive work based on the embodiments in the present application are within the scope of protection of the present application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

The application provides an impedance detection device of a biological body, which is used for detecting the impedance value of the biological body in the treatment operation process so as to monitor the change situation of the impedance value of the biological body, thereby being capable of assisting the safe proceeding of the treatment operation process. Wherein the therapeutic procedure may include, but is not limited to, ablation, coagulation, and the like. The present application describes an impedance detection device of a living body, taking an application of the impedance detection device of a living body in radio frequency ablation therapy as an example.

Fig. 1 is a schematic structural view of an impedance detection device for a living body according to an embodiment of the present invention. As shown in fig. 1, the impedance detection apparatus 100 of the living body 200 includes an excitation signal generation unit 31, a transmission unit 32, an impedance signal acquisition unit 33, and a processing unit 35. Wherein, the excitation signal generating unit 31 is configured to generate and output a high-frequency excitation signal.

The transmission unit 32 includes a first transmission terminal 321 and a second transmission terminal 322. The transmission unit 32 is electrically connected to the excitation signal generation unit 31 through the first transmission end 321 to receive the high-frequency excitation signal, and transmits the high-frequency excitation signal to the detection site 21 of the living body 200 through the second transmission end 322 (as shown in fig. 2).

As shown in fig. 2, the living body 200 may be a human body or other animals. In this embodiment, taking a human body as an example, the detection site 21 is a treatment site, such as a heart, and the impedance detection apparatus 100 of the living body 200 may further include a neutral electrode 41 electrically connected to the excitation signal generating unit 31, wherein the neutral electrode 41 is attached to a proper position of the body (i.e., the living body 200) of the patient, such as a leg or a back surface, during the treatment. The output end of the excitation signal generating unit 31 forms an impedance loop through the transmission unit 32, the living body 200, and the neutral electrode 41 in this order, and the high-frequency excitation signal can be transmitted through the impedance loop. Fig. 7 is a schematic diagram of an equivalent circuit of the impedance loop. In other embodiments, the detection site 21 may be a different site than the treatment site, such as a body surface site adjacent to the treatment site.

In this embodiment, the second transmission end 322 of the transmission unit 32 constitutes an impedance signal detection point 322. The impedance signal acquisition unit 33 is electrically connected to the impedance signal detection point 322, and is configured to acquire a sampling signal from the impedance signal detection point 322 in real time. For example, the impedance signal acquisition unit 33 may acquire a sampling signal from the impedance signal detection point 322 in real time during the treatment. In this embodiment, the sampling signal is a voltage signal.

The processing unit 35 is electrically connected to the impedance signal acquiring unit 33, and is configured to acquire the sampling signal and determine a real-time impedance value of the biological body corresponding to a real-time sampling value of the sampling signal according to a preset impedance calibration data table. The impedance calibration data table records mapping relations between a plurality of organism analog impedance values and sampling values of a plurality of sampling signals in advance.

Specifically, the processing unit 35 determines a real-time sampling value of the sampling signal when the sampling signal is acquired, and queries, in a preset impedance calibration data table, a biological real-time impedance value corresponding to the real-time sampling value of the sampling signal.

Referring to fig. 1 again, in the present embodiment, the impedance detecting apparatus 100 of the living body 200 further includes an operational amplifier unit 34 electrically connected between the impedance signal acquiring unit 33 and the processing unit 35, wherein the operational amplifier unit 34 is configured to receive the sampling signal output by the impedance signal acquiring unit 33 and amplify the sampling signal by a preset multiple.

It can be understood that, for safety, the voltage value of the high-frequency excitation signal applied to the living organism 200 is generally small, and accordingly, the sampling value of the sampling signal acquired by the impedance signal acquisition unit 33 is also small, so that the real-time impedance value of the living organism determined by the processing unit 35 according to the sampling value of the sampling signal acquired by the impedance signal acquisition unit 33 may have a large calculation error. By amplifying the sampling signal using the operational amplification unit 34, the calculation accuracy of the processing unit 35 can be improved to reduce the calculation error.

The circuit configuration and the operation principle of each of the units 31 to 35 described above will be described below.

Fig. 3 is a schematic circuit diagram of the excitation signal generating unit 31 and the transmission unit 32. As shown in fig. 3, the excitation signal generating unit 31 includes a first input terminal 311(Port 1), a first output terminal 312, and a waveform converting circuit 313 electrically connected between the first input terminal 311 and the first output terminal 312. The first input terminal 311 is configured to receive an input high frequency PWM (Pulse Width Modulation) square wave signal. It is understood that the PWM square wave signal inputted from the first input terminal 311, i.e., Port 1, can be generated in various ways, for example, the processing unit 35 can be a single chip, the PWM square wave signal can be generated by the processing unit 35, and the waveform of the PWM square wave signal refers to the waveform a shown in fig. 4.

In this embodiment, the waveform converting circuit 313 is configured to convert the high-frequency PWM square-wave signal into a high-frequency sine-wave signal, i.e., a high-frequency excitation signal. The waveform conversion circuit 313 includes an RC coupling circuit, an RC integrating circuit, and an LC filter circuit, which are electrically connected in sequence.

Specifically, the waveform conversion circuit 313 includes capacitors C1, C2, C3, resistors R1, R2, and an inductor L1. The first input terminal 311(Port 1), the capacitor C1, the resistor R2, the inductor L1, and the first output terminal 312 are sequentially connected in series.

One end of the resistor R1 is electrically connected to a connection circuit between the capacitor C1 and the resistor R2, and the other end is grounded. The capacitor C1 and the resistor R1 form the RC coupling circuit, and are used for filtering out the direct current component in the high-frequency PWM square-wave signal and only retaining the alternating current component. In the parameter selection, the capacitor C1 and the resistor R1 that form the RC coupling circuit need to satisfy τ ═ RC > > T (τ is a time constant, R is a resistance value, C is a capacitance value, and T is a period), and the output waveform is similar to the input waveform. When the RC coupling circuit stabilizes, a B waveform, an approximate PWM waveform with a downward shift in amplitude 1/2, is obtained as shown in fig. 4.

One end of the capacitor C2 is electrically connected to the connection circuit between the resistor R2 and the inductor L1, and the other end is grounded. The resistor R2 and the capacitor C2 form the RC integrating circuit, and are used for converting the high-frequency PWM square wave signal into an approximate triangular wave or sawtooth wave signal. Wherein, the resistor R2 and the capacitor C2 forming the RC integral circuit need to satisfy tau-RC when selecting parameters>>After the waveform B shown in fig. 4 passes through the RC integrating circuit, the waveform C shown in fig. 4, i.e., the approximate triangular waveform, is obtained. Expanding the triangular wave according to Fourier series to obtain

(wherein, U_mRepresenting the maximum amplitude).

The capacitor C3 is connected in parallel with the inductor L1 and is electrically connected between the resistor R2 and the first output terminal 312. The inductor L1 and the capacitor C3 form a parallel frequency selection circuit, namely the LC filter circuit is used for converting an approximately triangular wave or sawtooth wave signal into a sine wave signal, and the LC filter circuit formed by the inductor L1 and the capacitor C3 also has the function of isolating radio frequency current for ablation treatment. When the inductance L1 and the capacitance C3 forming the LC filter circuit are used for parameter selection, the passband cutoff frequency should be higher than the fundamental frequency of the triangular wave and lower than the third harmonic frequency of the triangular wave, and the Q value (quality factor) of the inductance L1 should be as large as possible to obtain better frequency selection performance. The waveform C shown in fig. 4 is converted into a waveform D shown in fig. 4 after being filtered by an LC filter circuit, and a sinusoidal excitation signal that can be applied to a biological load is obtained.

The first output terminal 312 is used for outputting the sine wave excitation signal, i.e. the high frequency excitation signal. The frequency of the high-frequency PWM square-wave signal is the same as that of the high-frequency excitation signal, for example, both the high-frequency PWM square-wave signal and the high-frequency excitation signal may be 50 KHZ. The excitation signal generating unit 31 of the present application can generate a 50kHz high-frequency excitation signal by constituting a coupling, integrating, and frequency-selecting circuit with simple components, and the circuit structure is relatively simple.

Referring to fig. 3 again, the transmission unit 32 further includes a voltage dividing resistor R3 electrically connected between the first transmission end 321 and the second transmission end 322(Port 2), and the transmission unit 32 transmits the high frequency excitation signal to the detection site 21 of the living body 200 through the voltage dividing resistor R3 and the second transmission end 322.

The second transmitting end 322 can be an electrode, and the electrode penetrates into the internal body tissue of the living body 200, i.e. the treatment site, such as the hypertrophic cardiac muscle in the ventricular septum. The high-frequency excitation signal is output from the first output terminal 312 of the excitation signal generating unit 31, and then applied to the detection site 21, i.e., the treatment site, of the living body 200 via the voltage dividing resistor R3 and the electrodes.

In this embodiment, the second transmission end 322 for transmitting the high-frequency excitation signal and the ablation electrode for transmitting the rf ablation current signal may share the same transmission channel, that is, the high-frequency excitation signal and the rf ablation current signal may be simultaneously superimposed on the ablation electrode. It will be appreciated that the high frequency excitation signal is simply an electrical signal applied to the biological subject 200 for the purpose of detecting the impedance of the biological subject, and is a different frequency electrical stimulation signal than the radio frequency current signal used for radio frequency ablation. Thus, the ablation electrode forms the impedance signal detection point, and the impedance signal acquisition unit 33 acquires the voltage of the high-frequency excitation signal at the impedance signal detection point. It is understood that, in another embodiment, the second transmission end 322 and the ablation electrode may correspond to different transmission channels, i.e., the second transmission end 322 may be another transmission electrode independent from the ablation electrode.

Fig. 5 is a schematic circuit structure diagram of the impedance signal acquisition unit 33. As shown in fig. 5, the impedance signal acquiring unit 33 includes a second input terminal 331(port 3), a second output terminal 332(port 4), and an anti-jamming circuit 333 electrically connected between the second input terminal 331 and the second output terminal 332. Wherein, the second input 331(port 3) is electrically connected to the impedance signal detecting point 322, and the second input 331 is configured to obtain the sampling signal from the impedance signal detecting point 322 in real time. It can be understood that the high frequency excitation signal is output from the first output terminal 312 of the excitation signal generating unit 31, and is attenuated by the voltage dividing resistor R3 to obtain the sampling signal with a reduced voltage value, but the frequency of the sampling signal is still the same as that of the high frequency excitation signal.

As mentioned above, the second transmission terminal 322 for transmitting the high-frequency excitation signal and the ablation electrode for transmitting the rf ablation current signal may share the same transmission channel. Therefore, an interference signal exists in the sampling signal acquired by the second input terminal 331 in real time from the impedance signal detection point 322. It is understood that when the second transmission end 322 and the ablation electrode do not share the same transmission channel, the rf ablation current signal may enter the impedance signal collection unit 33 from the impedance signal detection point 322 through the transmission of the living body 200, thereby interfering with the sampling signal. In this embodiment, the immunity circuit 333 is configured to perform signal processing on the sampling signal to filter an interference signal in the sampling signal. The anti-jamming circuit 333 includes a capacitor C4, an RC low-pass filter circuit, and an LC parallel frequency-selecting circuit, which are electrically connected in sequence.

Specifically, the anti-jamming circuit 333 includes capacitors C4, C8, C9, resistors R5, R6, and an inductor L2. Wherein the second input terminal 331(port 3), the capacitor C4, the resistor R5, the resistor R6, and the second output terminal 332(port 4) are sequentially connected in series.

The capacitor C4 is used to isolate the dc component of the sampled signal.

One end of the capacitor C8 is electrically connected to the connection circuit between the resistors R5 and R6, and the other end is grounded. The resistor R5 and the capacitor C8 form the RC low-pass filter circuit for passing the alternating current component in the sampled signal, i.e. passing the high-frequency excitation signal that is voltage attenuated by the transmission unit 32, mainly the voltage dividing resistor R3.

The inductor L2 is connected in parallel with the capacitor C9, and is electrically connected between the ground and the circuit connected between the resistors R5 and R6. The inductor L2 and the capacitor C9 form the LC parallel frequency selection circuit, and are used for filtering interference of power frequency in the sampling signal and radio frequency current signals for radio frequency ablation which are aliased in the sampling signal. When the inductance L2 and the capacitance C9 forming the LC parallel frequency selection circuit are used for parameter selection, the resonant frequency of the loop needs to be enabled

Equal to the frequency of the excitation signal and having a passband width

Should be small, i.e., the Q value (quality factor) is large. It can be understood that the larger the Q value, the narrower the passband, and the better the filtering effect.

It can be understood that, because the rf ablation current has large energy, the rf ablation signal will interfere with the sampling signal much more than other signals, which will cause significant interference to the impedance detection circuit of the living being 200, and therefore it is necessary to filter the rf ablation current as much as possible. By arranging the anti-interference circuit 333 in the impedance signal acquisition unit 33, a more significant filtering effect can be still obtained under the condition that the radio frequency ablation signal is mixed in the sampling signal, so that the accuracy of impedance detection is ensured. The power frequency is the frequency of the alternating current used in industry, generally the frequency of the commercial power, and is 50Hz in China.

The impedance signal detection unit 33 outputs the sampled signal processed by the interference rejection circuit 333 through a second output terminal 332(Port 4) thereof.

Fig. 6 is a schematic circuit diagram of the operational amplifier unit 34. As shown in fig. 6, the operational amplification unit 34 includes a third input terminal 341(Port5), a third output terminal 342(Port 6), and a filter circuit 343 and an operational amplification circuit 344 electrically connected between the third input terminal 341(Port5) and the third output terminal 342(Port 6). A third input terminal 341(Port5) is electrically connected to the second output terminal 332(Port 4) of the impedance signal acquiring unit 33, and the third input terminal 341 is configured to receive the sampling signal output by the impedance signal acquiring unit 33.

The filter circuit 343 is configured to filter the sampling signal received by the third input terminal 341(Port5) to filter an interference signal in the sampling signal, so as to ensure that the sampling signal subjected to operational amplification has no other interference. In this embodiment, the filter circuit 343 includes an inductor L3 and a capacitor C10, the inductor L3 and the capacitor C10 are connected in parallel to form a parallel frequency selection circuit, and the parallel frequency selection circuit is electrically connected between a connection circuit between the third input terminal 341(Port5) and the positive input terminal of the operational amplifier AR1 and a ground terminal.

The operational amplifier circuit 344 is configured to amplify the sampling signal by a preset multiple. Specifically, in the present embodiment, the operational amplification circuit 344 includes operational amplifiers AR1, AR2, AR3, and a diode D1. The operational amplifier AR1 is a non-inverting amplifier, and since the frequency of the sampling signal is high and the capacitance reactance of the capacitor C7 is negligible, the amplification factor of the operational amplifier AR1 is

The operational amplifier AR2 is an inverting amplifier, in which the resistances of the resistors R13 and R14 are equal, i.e., R13 is equal to R14, so the amplification factor of the operational amplifier AR2 is equal to

Diode D1 is a high-speed switching diode for rectification to obtain a dc signal for impedance calculation. The operational amplifier AR3 is a non-inverting amplifier with an amplification factor of

It is understood that the actual amplification of the operational amplifier circuit 344 may be adjusted according to the range and accuracy required for detection. Finally, the operational amplifier unit 34 outputs the amplified dc voltage signal through the third output terminal 342(Port 6).

It can be understood that, after the LC filtering pretreatment of the impedance signal acquisition unit 33, the sampling signal enters the operational amplification unit 34, LC filtering treatment is performed again, and then after in-phase amplification, rectification by the diode D1 and secondary amplification are performed, and finally, the interference signal included in the obtained sampling signal is small, thereby being beneficial to improving the accuracy of the biological impedance detection.

The equivalent circuit diagram of the impedance loop described above is described below.

The organism impedance is composed of a resistor, a capacitive reactance and an inductive reactance. Because the inductive reactance of the organism 200 is very weak, it is generally negligible. The capacitive reactance of the organism 200 is sensitive to frequency and is calculated by the formula of the capacitive reactance

It can be seen that the capacitive reactance is inversely proportional to the frequency, and the higher the frequency, the smaller the capacitive reactance. In the present embodiment, since the excitation signal output from the excitation signal generating unit 31 is a high-frequency excitation signal, for example, the frequency thereof is 50kHz, the capacitive reactance in this case can be ignored. Thus, the impedance of the living organism can be approximated as being purely resistive.

Fig. 7 shows an equivalent circuit schematic of the impedance loop. As shown in fig. 7, wherein the voltage Vo is the voltage of the high frequency excitation signal output from the first output terminal 312 of the excitation signal generating unit 31. The resistance Ro is an equivalent resistance of a transmission circuit from the first output terminal 312 of the pumping signal generation unit 31 to the second transmission terminal 322 of the transmission unit 32, that is, an equivalent resistance of the entire transmission circuit transmitting the high-frequency pumping signal. It is understood that the equivalent resistor Ro includes the resistance of the divider resistor R3 and the transmission cable, etc. In the present embodiment, the voltage dividing resistor R3 is a resistor having a large resistance. The resistance Rx is the equivalent organism impedance to be measured. Since the living body 200 is connected to the neutral electrode 41, the resistance Rx is equivalent to the ground. The voltage Vadc is the voltage at the impedance signal detection point 322. That is, in the present embodiment, the sampling signal is a voltage signal Vadc.

According to the principle of resistance voltage division:

where Uo is the voltage value of the voltage Vo, and Uadc is the voltage value of the voltage signal Vadc. In this way, the relationship between the body impedance Rx and the voltage value Uadc of the sampling signal Vadc is obtained as follows:

fig. 8 is a graph illustrating a relationship between the voltage value Uadc of the sampling signal Vadc and the impedance value of the living body impedance Rx. As can be seen from fig. 8, the voltage value Uadc of the sampling signal Vadc is in a positive correlation with the biological impedance Rx, and is in an approximately linear relationship within a certain range.

Referring to fig. 7 again, in the present embodiment, the processing unit 35 includes a data acquisition module 351 and a calculation module 352, wherein the data acquisition module 351 may adopt an ADC acquisition module for acquiring the sampling signal Vadc and determining a real-time sampling value of the sampling signal Vadc. It is understood that, in this embodiment, the sampling signal Vadc acquired by the data acquisition module 351 is a sampling signal that is subjected to signal processing and amplification by the impedance signal acquisition unit 33 and the operational amplification unit 34.

In this embodiment, the calculating module 352 is configured to determine a real-time impedance value of a biological body corresponding to a real-time sampling value of the sampling signal according to the preset impedance calibration data table.

Fig. 9 is a schematic diagram of the preset impedance calibration data table. The impedance detection apparatus 100 of the living body 200 may further include a memory 42, and the impedance calibration data table may be stored in the memory 42 in advance. As shown in fig. 9, the impedance calibration data table records mapping relationships between a plurality of biological analog impedance values and sampling values of a plurality of sampling signals in advance.

The impedance calibration data table may be pre-established before the device leaves a factory, and the data recorded in the impedance calibration data table may be determined by: the impedance of the living body 200 is simulated by using a plurality of high-precision non-inductive resistors, the sampling signal at the impedance signal detection point is detected by using the impedance detection device 100, the voltage value of the sampling signal acquired by the data acquisition module 351 (that is, the voltage value of the voltage signal transmitted to the data acquisition module 351 after the voltage signal at the impedance signal detection point passes through the impedance signal acquisition unit 33 and the operational amplification unit 34) is recorded at different living body simulated impedance values, and finally the impedance calibration data table is created according to the correspondence relationship between the plurality of living body simulated impedance values and the voltage values of the plurality of sampling signals.

In this embodiment, the calculating module 352 is configured to call a preset impedance calibration data table and query the impedance calibration data table for a real-time impedance value of a living body corresponding to a real-time sampling value of the sampling signal.

Specifically, when the data acquisition module 351 acquires a real-time sampling value of the sampled signal Vadc, i.e., the voltage value Uadc_xEqual to a certain sampling value Uadc in the impedance calibration data table_nThen, the impedance calibration data table and the sampling value Uadc_nCorresponding biological analog impedance value R_nI.e. the real-time impedance value of the biological body 200.

In this embodiment, when the impedance calibration data table does not look up the biological real-time impedance value corresponding to the real-time sampling value of the sampling signal, the calculating module 352 is further configured to continue to look up two sampling values closest to the real-time sampling value of the sampling signal and the biological analog impedance value corresponding to the two sampling values in the impedance calibration data table, and calculate the biological real-time impedance value corresponding to the real-time sampling value of the sampling signal according to the biological analog impedance values corresponding to the two sampling values and a preset linear formula.

Specifically, as described above, the voltage value Uadc of the sampling signal Vadc is in a positive correlation with the living body impedance Rx, and is in an approximately linear relationship within a certain range. Suppose the real-time sample value of the current sampling signal is Uadc_xTwo sampling values which are closest to the real-time sampling value of the sampling signal in the impedance calibration data table are Uadc_n-1And Uadc_nI.e. Uadc_n-1<Uadc_x<Uadc_nAnd two sampled values are Uadc_n-1And Uadc_nCorresponding to a biological analog impedance value of R_n-1And R_nTwo-point equation based on straight lines

It can be known that the real-time impedance value Rx of the living body can be calculated by the following linear formula:

it can be understood that the more data recorded in the impedance calibration data table is, the more the calculation accuracy of the real-time impedance value of the living body is improved.

The impedance detection device 100 determines the real-time impedance value of the organism 200 through presetting according to the characteristic that the impedance value of the organism 200 and the sampling value of the sampling signal form an approximate linear relation in a certain range, has quick response, can accurately and quickly detect the real-time impedance value of the organism 200, can monitor the change of the organism impedance in real time in the treatment process, provides reference information for medical staff, and further ensures the safe treatment. Specifically, the real-time impedance value of the organism is determined by directly checking a table in the detection process or by calculating a sectional table and a formula.

It can be understood that, since the equivalent resistor Ro includes the resistance of the transmission cable and the like in addition to the resistance of the voltage dividing resistor R3, there is a certain error in the measurement of the actual resistance of the equivalent resistor Ro if the voltage dividing formula is used

To calculate the real-time impedance value Rx of the living body may cause an error in the calculation result of the real-time impedance value Rx of the living body.

The impedance detection device 100 of the present application determines the real-time impedance value of the living body 200 by presetting the impedance calibration data table and in the detection process, in a table look-up manner or a sectional table look-up manner and a formula calculation manner, so as to effectively eliminate the calculation error, thereby improving the accuracy of the impedance detection of the living body 200, and avoiding the influence of the actual resistance value measurement error of the equivalent resistor Ro on the calculation of the real-time impedance value Rx of the living body.

In addition, the impedance detection device 100 of the present application can detect the impedance value of the living organism 200 by generating the excitation signal of the fixed voltage, only performing voltage sampling, and without performing current sampling, thereby achieving the effect of simplifying the structure of the detection circuit, thereby reducing the cost and the volume of the impedance detection device 100 of the living organism 200, and simultaneously enabling the impedance detection device 100 of the living organism 200 to have a faster dynamic response speed; further, since the impedance detection device 100 of the living body 200 has a simple circuit configuration, the living body impedance circuit can be equivalent to a simple resistance voltage division model, and the detected actual impedance value of the living body 200 can be more accurate and reliable.

The present application also provides a method for detecting an impedance of a living body, which is implemented by the impedance detection apparatus 100 of the living body 200 described above. Fig. 10 is a flowchart of an impedance detection method of a living body 200 according to an embodiment of the present application. It should be noted that the method for detecting the impedance of the living body 200 described in the embodiment of the present application is not limited to the steps and the sequence in the flowchart shown in fig. 10. Steps in the illustrated flowcharts may be added, removed, or changed in order according to various needs. As shown in fig. 10, the method for detecting the impedance of a living body includes the following steps.

Step 1001, a real-time sampling value of a sampling signal at an impedance signal detection point is obtained.

For details of the sampling signal at the impedance signal detection point, reference may be made to the above detailed description of the impedance detection apparatus 100 of the living body 200, which is not repeated herein.

Step 1002, a preset impedance calibration data table is queried to determine a real-time impedance value of the biological body corresponding to the real-time sampling value of the sampling signal.

The impedance calibration data table records mapping relations between a plurality of organism analog impedance values and sampling values of a plurality of sampling signals in advance.

Fig. 11 is a flowchart of another method for detecting impedance of a living body according to the embodiment of the present application. As shown in fig. 11, the method for detecting the impedance of a living body includes the following steps.

Step 1101, acquiring a real-time sampling value of the sampling signal of the impedance signal detection point.

Step 1102, a preset impedance calibration data table is called.

Step 1103, looking up a first sampling value equal to the real-time sampling value of the sampling signal in the impedance calibration data table.

Step 1104, determining whether the first sampling value is found in the impedance calibration data table. If the first sampling value is not found, step 1105 is executed. Otherwise, if the first sampling value is found, step 1107 is executed.

Step 1105, continuously inquiring two sampling values closest to the real-time sampling value of the sampling signal and the biological body analog impedance value corresponding to the two sampling values in the impedance calibration data table.

And step 1106, calculating a real-time impedance value of the biological body corresponding to the real-time sampling value of the sampling signal according to the analog impedance value of the biological body corresponding to the two sampling values and a preset linear formula.

As mentioned above, the preset linear formula can be set as:

wherein Uadc_xFor the current sampled signal, the real-time sampled value is Uadc_n-1And Uadc_nFor the real-time sampling value Uadc of the sampling signal inquired in the impedance calibration data table_xTwo closest sampled values, i.e. Uadc_n-1<Uadc_x<Uadc_n，R_n-1And R_nTo the two sampled values Uadc_n-1And Uadc_nThe corresponding bio-analog impedance value.

Step 1107, continuously inquiring the biological body analog impedance value corresponding to the first sampling value in the impedance calibration data table, and using the biological body analog impedance value corresponding to the first sampling value as the biological body real-time impedance value corresponding to the real-time sampling value of the sampling signal.

According to the method for detecting the impedance of the organism, the impedance calibration data table is preset according to the characteristic that the impedance value of the organism and the sampling value of the sampling signal form an approximate linear relation in a certain range, the real-time impedance value of the organism is determined in the detection process in a table look-up mode or a sectional table look-up mode and a formula calculation mode, the real-time impedance value of the organism can be detected accurately and quickly in real time, the change of the impedance of the organism can be monitored in real time in the treatment process, reference information is provided for medical staff, and then the safe treatment is ensured.

It will be understood by those skilled in the art that the foregoing schematic diagram 1 is merely an example of the impedance detection apparatus 100 for implementing the impedance detection method of the living body 200, and does not constitute a limitation of the impedance detection apparatus 100 of the living body 200, and the impedance detection apparatus 100 of the living body 200 may include more or less components than those shown in the drawings, or may combine some components, or different components, for example, the impedance detection apparatus 100 of the living body 200 may further include a display unit, etc.

The memory 42 may include high speed random access memory and may also include non-volatile memory such as a hard disk, a memory, a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), at least one magnetic disk storage device, a Flash memory device, or other volatile solid state storage device.

The memory 42 may also have a computer program stored therein. The computer program may be divided into one or more modules/units, which are stored in the memory 42 and executed by the processing unit 35 to perform the method of impedance detection of a biological body of the present application. The one or more modules/units may be a series of computer program instruction segments capable of performing specific functions, which are used to describe the execution process of the computer program in the impedance detection apparatus 100 of the living being 200.

The Processing Unit 35 may be a single chip, a Central Processing Unit (CPU), or other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA) or other Programmable logic device, a discrete Gate or transistor logic device, a discrete hardware component, or the like. The processing unit 35 implements the function of the bio-impedance detection by running or executing the computer program and/or the module/unit stored in the memory 42 and calling up the data stored in the memory 42.

In the present embodiment, the processing unit 35 implements the steps of the above-described method for detecting impedance of each living body, for example, steps 1001 to 1002 shown in fig. 10 or steps 1101 to 1106 shown in fig. 11, when executing the computer program.

The present application also provides a radiofrequency ablation system using the impedance detection device 100 of the living organism 200 described above. Fig. 12 is a schematic structural diagram of the radiofrequency ablation system. As shown in fig. 12, the rf ablation system 1000 includes an rf energy generating unit 500, an ablation device 600, and the impedance detecting device 100. The rf energy generating unit 500 is configured to generate an rf current signal with a set power during the rf ablation process to provide the rf energy required by the rf ablation. The impedance detection device 100 of the living body 200 is used for detecting the impedance value of the living body 200 in real time in the radiofrequency ablation process so as to monitor the change of the impedance value of the living body 200, thereby assisting the safe proceeding of the radiofrequency ablation operation.

The excitation signal generating unit 31 and the rf energy generating unit 500 of the impedance detecting apparatus 100 of the living body 200 may be two independent apparatuses or may be provided in the same apparatus.

The rf energy generating unit 500 is also electrically connected to the ablation device 600 (e.g., an ablation electrode). The ablation device 600 is configured to be inserted into an ablation site (for example, a treatment site of the living body 200 described above) during rf ablation, receive rf energy output by the rf energy generation unit 500, and release the rf energy to the ablation site, so as to perform rf ablation on the ablation site, thereby achieving the purpose of treating diseased tissue. The ablation site/treatment site refers to a lesion site in the living body 200, such as a lesion tissue of the heart or other lesion tissue. Taking hypertrophic cardiomyopathy as an example, the ablation device 600 is inserted into the heart of a patient via the apical approach to perform radio frequency ablation on hypertrophic ventricular septal myocardium to treat hypertrophic cardiomyopathy.

In the present embodiment, the detection site 21 and the treatment site are the same site. In this way, in the impedance detecting apparatus 100 of the living organism 200, as described above, the second transmitting terminal 322 for transmitting the high-frequency excitation signal and the ablation electrode for transmitting the rf ablation current signal may share the same transmitting channel, that is, the transmitting unit 32 may be partially or entirely disposed on the ablation apparatus 600.

In this embodiment, the processing unit 35 of the impedance detecting apparatus 100 of the living body 200 is further electrically connected to the excitation signal generating unit 31 and the rf energy generating unit 500, respectively, and is configured to provide the excitation signal generating unit 31 with a high-frequency PWM square wave signal, analyze a change of the impedance value of the living body within a preset time range according to the determined actual impedance value of the living body 200, and adjust the rf current signal output by the rf energy generating unit 500 according to the analysis result, for example, adjust the output state and/or the magnitude of the rf current signal, so as to avoid an abnormal condition that the cell tissue of the living body 200 at the ablation site is carbonized, scabbed or dropped during the rf ablation process, which may result in an enlarged wound area, a large amount of bleeding, even perforation, etc. at the treatment site.

It can be seen that by using the above-mentioned impedance detection device 100 of the living body 200 in the rf ablation system 1000, an effective solution can be provided for detecting the impedance of the living body in real time during the rf ablation treatment.

Finally, it should be noted that the above embodiments are only for illustrating the technical solutions of the present application and not for limiting, and although the present application is described in detail with reference to the above preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present application without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. An impedance detection device for a living body, comprising:

an excitation signal generating unit for generating and outputting a high-frequency excitation signal;

the transmission unit comprises a first transmission end and a second transmission end, is electrically connected with the excitation signal generation unit through the first transmission end to receive the high-frequency excitation signal, and transmits the high-frequency excitation signal to a detection part on the organism through the second transmission end, wherein the second transmission end forms an impedance signal detection point;

the impedance signal acquisition unit is electrically connected with the impedance signal detection point and is used for acquiring a sampling signal from the impedance signal detection point in real time; and

and the processing unit is electrically connected with the impedance signal acquisition unit and is used for acquiring the sampling signal and determining a biological real-time impedance value corresponding to a real-time sampling value of the sampling signal according to a preset impedance calibration data table, wherein the impedance calibration data table records the mapping relation between a plurality of biological analog impedance values and the sampling values of a plurality of sampling signals in advance.

2. The apparatus according to claim 1, wherein the processing unit comprises a data acquisition module and a calculation module, the data acquisition module is used for acquiring the sampling signal and determining a real-time sampling value of the sampling signal;

the calculation module is used for calling a preset impedance calibration data table and inquiring a biological real-time impedance value corresponding to a real-time sampling value of the sampling signal in the impedance calibration data table.

3. The apparatus according to claim 2, wherein when the impedance calibration data table does not look up the real-time impedance value of the living organism corresponding to the real-time sampling value of the sampling signal, the calculating module is further configured to continue looking up two sampling values closest to the real-time sampling value of the sampling signal and the simulated impedance values of the living organism corresponding to the two sampling values in the impedance calibration data table, and calculate the real-time impedance value of the living organism corresponding to the real-time sampling value of the sampling signal according to the simulated impedance values of the living organism corresponding to the two sampling values and a preset linear formula.

4. The apparatus according to claim 1, wherein the transmission unit further comprises a voltage-dividing resistor electrically connected between the first transmission terminal and the second transmission terminal, and the transmission unit transmits the high-frequency excitation signal to the detection site of the living body through the voltage-dividing resistor and the second transmission terminal.

5. The apparatus according to any one of claims 1 to 4, further comprising an operational amplifier unit electrically connected between the impedance signal acquisition unit and the processing unit, wherein the operational amplifier unit is configured to receive the sampling signal output by the impedance signal acquisition unit and amplify the sampling signal by a predetermined factor.

6. The apparatus according to claim 5, wherein the operational amplifier unit comprises a filter circuit and an operational amplifier circuit, wherein the filter circuit is configured to filter the sampled signal received by the operational amplifier unit to filter an interference signal in the sampled signal; the operational amplification circuit is used for amplifying the sampling signal by a preset multiple.

7. The apparatus according to any one of claims 1 to 4, wherein said excitation signal generating unit includes a first input terminal, a first output terminal, and a waveform converting circuit electrically connected between said first input terminal and said first output terminal, wherein,

the first input end is used for receiving an input high-frequency PWM square wave signal;

the waveform conversion circuit is used for converting the high-frequency PWM square wave signal into a high-frequency sine wave signal, wherein the high-frequency sine wave is the high-frequency excitation signal; and

the first output end is used for outputting the high-frequency excitation signal.

8. The apparatus according to claim 7, wherein the processing unit is further electrically connected to the excitation signal generating unit, and the processing unit is configured to provide the excitation signal generating unit with the high-frequency PWM square-wave signal.

9. The apparatus according to any one of claims 1 to 4, wherein the impedance signal acquiring unit further comprises an anti-interference circuit for performing signal processing on the sampled signal to filter out interference signals in the sampled signal.

10. The apparatus for detecting impedance of a living body according to claim 9, wherein said anti-interference circuit comprises a capacitor, an RC low-pass filter circuit, and an LC parallel frequency-selecting circuit, which are electrically connected in this order,

the capacitor is used for isolating the direct current component in the sampling signal;

the RC low-pass filter circuit is used for passing an alternating current component in the sampling signal;

the LC parallel frequency selection circuit is used for filtering interference of power frequency in the sampling signals and radio frequency current signals for radio frequency ablation which are mixed in the sampling signals.

11. A radio frequency ablation system comprising a radio frequency energy generation unit, an ablation device, and an impedance detection device of the living body according to any one of claims 1 to 10;

the radio frequency energy generating unit is used for providing radio frequency energy required by radio frequency ablation;

the ablation device is electrically connected with the radio frequency energy generation unit and is used for being inserted into a treatment part of an organism during radio frequency ablation, receiving the radio frequency energy output by the radio frequency energy generation unit and releasing the radio frequency energy to the treatment part so as to perform radio frequency ablation on the treatment part.

12. The rf ablation system of claim 11, wherein the detection site is the same site as the treatment site, and the transmission unit is partially or fully disposed on the ablation device.

13. The rf ablation system of claim 11, wherein the processing unit of the impedance detection device of the living body is further electrically connected to the rf energy generating unit, and the processing unit is configured to analyze a variation of the impedance value of the living body within a preset time range according to the determined actual impedance value of the living body, and adjust the rf current signal output by the rf energy generating unit according to the analysis result.