Radio frequency signal generator for radio frequency ablation

Abstract

The invention discloses a radio frequency signal generator for radio frequency ablation, and belongs to the technical field of signal generators. The invention aims to solve the problems of high complexity and poor stability of generated signals of an existing radiofrequency ablation signal generator. A main control module sends frequency, amplitude and phase setting commands to a main channel and an auxiliary channel of a DDS module according to required radio frequency ablation signals; the DDS module respectively outputs a radio frequency ablation signal and a radio frequency measurement signal with corresponding frequency, amplitude and phase from the main channel and the auxiliary channel according to a set command; the linear power amplifier and impedance matching module carries out amplification and impedance matching on the radiofrequency ablation signal and then outputs the radiofrequency ablation signal to an ablation catheter; the VIP measurement module monitors a radio frequency ablation signal or a radio frequency measurement signal fed back by the ablation catheter in real time, and the main control module compares the feedback signal with the required radio frequency ablation signal and sends an adjustment control signal to the DDS module in real time. The method is suitable for generating radio frequency ablation signals.

Description

Technical Field

[0001] The invention belongs to the technical field of signal generators. Background Art

[0002] In the clinical application of modern medicine, cardiac electrophysiology is an important branch. Arrhythmia (atrial fibrillation) refers to abnormal changes in heart rhythm and heart rate, which are mainly caused by changes in the generation or conduction of electrical activity in the myocardium. At present, in the process of electrophysiological treatment, ablation surgery is the main means of treating electrophysiological diseases. Commonly used treatment options in ablation methods include radiofrequency ablation, cryoablation and pulsed electric field ablation.

[0003] Radiofrequency ablation is a relatively common method of surgical treatment. Among the three different ablation methods, it belongs to the traditional ablation treatment method. After the tip electrode of the radiofrequency ablation catheter contacts the lesion site of the heart or other target tissue, the radiofrequency ablation energy is transmitted to the target tissue to achieve the treatment process.

[0004] Radiofrequency ablation energy is usually generated by sampling oscillator circuits or PWM circuits. The frequency stability of oscillator circuits is usually limited and is generally susceptible to temperature drift; PWM radiofrequency ablation energy generators usually rely on high-power and high-speed MOS switches, which are challenging to switch stably at high frequencies. In addition, the output waveform of this development model is not a native sine wave and requires filtering and shaping.

[0005] In traditional RF ablation products, sampling oscillation circuits or PWM circuits are usually used to generate RF ablation signals. Using an oscillation circuit to generate RF ablation signals is a classic method. Since oscillation circuits generally contain basic capacitors or inductors, these basic components are easily affected by temperature drift, which in turn affects the frequency stability of the RF ablation signal. Usually, the stability of ±1KHz is difficult to achieve. This may not be a big deal for ordinary consumer products, but it will bring uncertainty to medical equipment involving life safety.

[0006] There are also sampling PWM circuits to generate radiofrequency ablation signals. The basic principle is that the PWM signal is amplified by the MOS tube switch circuit, which is essentially a switch power amplification. First, the stability of the high-speed MOS switch tube under high-power conditions is a challenge; second, the signal after this switch amplification is not a native sine wave, and the harmonic components are complex, and it often needs to be supplemented by a high-power filter to be shaped into a sine wave.

[0007] In recent years, companies such as Kunshan Leisheng (authorization announcement number CN 207627397 U), Hangzhou Nuocheng (application publication number CN111214289A), and Hangzhou Kunbo (application publication number CN 219000528 U) have proposed PWM radiofrequency ablation energy generation mechanisms and related radiofrequency ablation systems. The sampling PWM mechanism can indeed better control the frequency stability compared to the resonant circuit, but the stability of the high-frequency switch MOS tube introduced by this solution under high-power conditions is a challenge; secondly, the signal amplified by this switch is not a native sine wave, and it must rely on a high-power filter to be shaped into a sine wave, which increases the complexity and risk of the system. Summary of the invention

[0008] The present invention aims to solve the problems of high complexity and poor stability of the generated signal of the existing radio frequency ablation signal generator, and provides a radio frequency signal generator for radio frequency ablation.

[0009] The radio frequency signal generator for radio frequency ablation described in the present invention comprises: an AC-DC isolated power supply, a DDS module, a main control module, a VIP measurement module, a temperature measurement module, and a linear power amplifier and impedance matching module;

[0010] The main control module sends frequency, amplitude and phase setting commands to the DDS module according to the required radiofrequency ablation signal;

[0011] The DDS module first outputs a radio frequency measurement signal of corresponding frequency, amplitude and phase through an auxiliary channel according to the frequency, amplitude and phase commands set by the main control module, and sends the radio frequency measurement signal to the ablation catheter;

[0012] The VIP measurement module is used to receive the radiofrequency ablation signal or measurement signal fed back by the ablation catheter in real time; extract the current, voltage and phase of the received signal, and send the extracted current, voltage and phase to the main control module;

[0013] If the main control module receives the current, voltage and phase of the feedback measurement signal within the T time, the main control module calculates the bioelectrical impedance obtained by the contact between the catheter and the human tissue using the current, voltage and phase, and determines whether the bioelectrical impedance is within the impedance threshold range. If so, the driving signal generated by the radiofrequency ablation signal is sent to the DDS module, otherwise, a warning signal is issued; the impedance threshold range is: 50Ω to 250Ω;

[0014] If the main control module does not receive the feedback measurement signal within T time, it will issue a warning signal;

[0015] The DDS module receives the driving signal, and outputs a radiofrequency ablation signal of corresponding frequency, amplitude and phase through the main channel according to the frequency, amplitude and phase commands set by the main control module; and sends the radiofrequency ablation signal to the linear power amplifier and impedance matching module;

[0016] The main control module also sends amplification factor setting signals to the linear power amplifier and impedance matching modules;

[0017] The linear power amplifier and impedance matching module performs linear amplification and impedance matching on the received radiofrequency ablation signal according to the amplification control signal sent by the main control module, and then outputs it to the ablation catheter;

[0018] The main control module also compares the frequency, amplitude and phase of the fed-back radiofrequency ablation signal with the frequency, amplitude and phase of the required radiofrequency ablation signal, and sends an output signal adjustment control signal to the DDS module in real time according to the comparison result.

[0019] Furthermore, the present invention also includes a temperature measurement module, which is used to monitor the temperature signal of the thermocouple at the tip of the radiofrequency ablation catheter and send the temperature signal to the main control module. The main control module adjusts the power gain of the linear power amplifier and the impedance matching module according to the received temperature signal.

[0020] Furthermore, the present invention also includes an isolation circuit I and an isolation circuit II;

[0021] The main control module is connected to the VIP measurement module, the temperature measurement module, the DDS module and the linear power amplifier and impedance matching module through an isolation circuit I;

[0022] The VIP measurement module, the temperature measurement module, the linear power amplifier and the impedance matching module are connected to the ablation catheter and the negative electrode plate through the isolation circuit II.

[0023] Furthermore, the present invention further includes a display module, and the main control module sends the frequency, amplitude and phase of the required radiofrequency ablation signal and the feedback signal voltage, current and phase signal monitored by the VIP measurement module to the display module;

[0024] The display module is used to display the received signal.

[0025] Furthermore, in the present invention, the display module is also used to display a warning signal.

[0026] Further, in the present invention, the linear power amplifier and impedance matching module includes two transistors T1 and T2, three resistors Rd1, Rd2 and Rs, an inductor coil L, and an impedance matching group;

[0027] The RF ablation signal is input to the gate of transistor T1, the source of transistor T1 is connected to the ground through resistor Rs, and the drain is connected to the power supply V through resistor Rd1. DD , the drain of transistor T1 is also connected to the source of transistor T2;

[0028] The given static operating point voltage V of the gate of transistor T2 GG , the drain of T2 is connected to one end of the primary coil of inductor L, and the other end of the primary coil of inductor L is connected to the power supply V through resistor Rd2 DD ;

[0029] One end of the secondary coil of the inductor L is connected to the electrical signal input end of the ablation catheter through an impedance matching group;

[0030] The other end of the secondary coil of the inductor L is connected to the negative plate through an impedance matching group.

[0031] Furthermore, the present invention also includes an AC-DC isolated power supply, and the AC-DC isolated power supply is used to power the DDS module.

[0032] The present invention uses a DDS module to receive the frequency, amplitude and phase setting commands from the main control module, generates a small radiofrequency ablation signal with specified characteristics (frequency, amplitude and phase), and sends it to the power amplifier module behind. The linear power amplifier module receives the small radiofrequency ablation signal, and after amplification, impedance matching and isolation, it outputs a stable and accurate radiofrequency ablation energy signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a principle block diagram of the radio frequency signal generator for radio frequency ablation according to the present invention;

[0034] Figure 2 It is a schematic diagram of the linear power amplifier and impedance matching module described in the specific embodiment. DETAILED DESCRIPTION

[0035] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0036] Specific implementation method 1: refer to Figure 1 Specifically describe this embodiment, the embodiment described in this embodiment includes: including: AC-DC isolated power supply 1, DDS module 2, main control module 4, VIP measurement module 6, temperature measurement module 7 and linear power amplifier and impedance matching module 8;

[0037] The main control module 4 sends frequency, amplitude and phase setting commands to the DDS module 2 according to the required radiofrequency ablation signal;

[0038] The DDS module 2 first outputs a radio frequency measurement signal of corresponding frequency, amplitude and phase through an auxiliary channel according to the frequency, amplitude and phase commands set by the main control module 4, and sends the radio frequency measurement signal to the ablation catheter;

[0039] The VIP measurement module 6 is used to receive the radiofrequency ablation signal or measurement signal fed back by the ablation catheter in real time; extract the current, voltage and phase of the received signal, and send the extracted current, voltage and phase to the main control module 4;

[0040] If the main control module 4 receives the current, voltage and phase of the feedback measurement signal within the T time, it uses the current, voltage and phase to calculate the bioelectrical impedance obtained by the contact between the catheter and the human tissue, and determines whether the bioelectrical impedance is within the impedance threshold range. If so, it sends the driving signal generated by the radiofrequency ablation signal to the DDS module 2, otherwise, it sends a warning signal; the impedance threshold range is: 50Ω to 250Ω;

[0041] If the main control module 4 does not receive the feedback measurement signal within T time, it will issue a warning signal;

[0042] The DDS module 2 receives the driving signal, and outputs a radiofrequency ablation signal of corresponding frequency, amplitude and phase through the main channel according to the frequency, amplitude and phase commands set by the main control module 4; and sends the radiofrequency ablation signal to the linear power amplifier and impedance matching module 8;

[0043] The main control module 4 also sends an amplification factor setting signal to the linear power amplifier and impedance matching module 8;

[0044] The linear power amplifier and impedance matching module 8 performs linear amplification and impedance matching on the received radiofrequency ablation signal according to the amplification control signal sent by the main control module 4, and then outputs it to the ablation catheter;

[0045] The main control module 4 also compares the frequency, amplitude and phase of the fed-back radiofrequency ablation signal with the frequency, amplitude and phase of the required radiofrequency ablation signal, and sends an output signal adjustment control signal to the DDS module 2 in real time according to the comparison result.

[0046] Furthermore, in this embodiment, a temperature measurement module 7 is also included, which is used to monitor the temperature signal of the thermocouple at the tip end of the radiofrequency ablation catheter and send the temperature signal to the main control module 4. The main control module 4 adjusts the power gain of the linear power amplifier and impedance matching module 8 according to the received temperature signal.

[0047] Furthermore, in this embodiment, an isolation circuit I3 and an isolation circuit II9 are also included;

[0048] The main control module 4 is connected to the VIP measurement module 6, the temperature measurement module 7, the DDS module 2 and the linear power amplifier and impedance matching module 8 through the isolation circuit I3;

[0049] The VIP measurement module 6, the temperature measurement module 7 and the linear power amplifier and impedance matching module 8 are connected to the ablation catheter and the negative electrode plate through the isolation circuit II9.

[0050] Furthermore, in this embodiment, a display module 5 is also included, and the main control module 4 sends the frequency, amplitude and phase of the required radiofrequency ablation signal and the feedback signal voltage, current and phase signal monitored by the VIP measurement module 6 to the display module 5;

[0051] The display module 5 is used to display the received signal.

[0052] Furthermore, in this embodiment, the display module 5 is also used to display a warning signal.

[0053] Furthermore, combined with Figure 2 To illustrate this embodiment, in this embodiment, the linear power amplifier and impedance matching module 8 includes two transistors T1 and T2, three resistors Rd1, Rd2 and Rs, an inductor coil L, and an impedance matching group;

[0054] The radiofrequency ablation signal is input to the gate of transistor T1, the source of transistor T1 is connected to the ground through resistor Rs, and the drain is connected to the power supply V through resistor Rd1. DD , the drain of transistor T1 is also connected to the source of transistor T2;

[0055] The given static operating point voltage V of the gate of transistor T2 GG , the drain of T2 is connected to one end of the primary coil of inductor L, and the other end of the primary coil of inductor L is connected to the power supply V through resistor Rd2 DD ;

[0056] One end of the secondary coil of the inductor L is connected to the electrical signal input end of the ablation catheter through an impedance matching group;

[0057] The other end of the secondary coil of the inductor L is connected to the negative plate through an impedance matching group.

[0058] Furthermore, in this embodiment, an AC-DC isolated power supply 1 is also included, and the AC-DC isolated power supply 1 is used to power the DDS module 2 .

[0059] In the present invention, the DDS module adopts the AD9959 chip, which contains multiple signal channels. It can output a small radiofrequency ablation signal to perform ablation treatment on human tissue after power amplification and filtering, and can also output a small signal required for voltage, current and phase measurement, and it is stable and high in precision.

[0060] Combination Figure 2 To illustrate, the DC power supply and LDO linear power supply together power the DDS module, the high-stability crystal oscillator provides an accurate timing reference, and the main control module controls the output frequency, amplitude and phase of the DDS module through the I2C bus. The ablation treatment signal, the small measurement signal and the returned sampling signal generated by the DDS module are routed by a multiplexer.

[0061] Linear power amplification and impedance matching:

[0062] The linear power amplifier module consists of an amplifier part composed of a power MOS tube and an impedance matching part composed of passive components. It cooperates with impedance measurement and control algorithms to achieve optimized power output performance. The linear power amplifier is built with MOS tubes and matched with impedance matching arrays.

[0063] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that the features described in conjunction with a single embodiment may be used in other described embodiments.

Claims

1. A radio frequency signal generator for radio frequency ablation, characterized in that: include: AC-DC isolated power supply (1), DDS module (2), main control module (4), VIP measurement module (6), temperature measurement module (7) and linear power amplifier and impedance matching module (8); The main control module (4) sends frequency, amplitude and phase setting commands to the DDS module (2) according to the required radiofrequency ablation signal; The DDS module (2) first outputs a radio frequency measurement signal of corresponding frequency, amplitude and phase through an auxiliary channel according to the frequency, amplitude and phase commands set by the main control module (4), and sends the radio frequency measurement signal to the ablation catheter; The VIP measurement module (6) is used to receive in real time the radiofrequency ablation signal or measurement signal fed back by the ablation catheter; extract the current, voltage and phase of the received signal, and send the extracted current, voltage and phase to the main control module (4); If the main control module (4) receives the current, voltage and phase of the feedback measurement signal within the time T, it calculates the bioelectrical impedance obtained by the contact between the catheter and the human tissue using the current, voltage and phase, and determines whether the bioelectrical impedance is within the impedance threshold range. If so, it sends a driving signal generated by the radiofrequency ablation signal to the DDS module (2); otherwise, it sends a warning signal; If the main control module (4) does not receive the feedback measurement signal within the time T, it will issue a warning signal; The DDS module (2) receives the driving signal, and outputs a radiofrequency ablation signal of corresponding frequency, amplitude and phase through a main channel according to the frequency, amplitude and phase commands set by the main control module (4); and sends the radiofrequency ablation signal to the linear power amplifier and impedance matching module (8); The main control module (4) also sends an amplification factor setting signal to the linear power amplifier and impedance matching module (8); The linear power amplifier and impedance matching module (8) performs linear amplification and impedance matching on the received radiofrequency ablation signal according to the amplification control signal sent by the main control module (4), and then outputs the signal to the ablation catheter; The main control module (4) also compares the frequency, amplitude and phase of the fed-back radiofrequency ablation signal with the frequency, amplitude and phase of the required radiofrequency ablation signal, and sends an output signal adjustment control signal to the DDS module (2) in real time according to the comparison result.

2. The radio frequency signal generator for radio frequency ablation according to claim 1, characterized in that: It also includes a temperature measurement module (7), which is used to monitor the temperature signal of the thermocouple at the tip of the radiofrequency ablation catheter and send the temperature signal to the main control module (4). The main control module (4) adjusts the power amplification factor of the linear power amplifier and the impedance matching module (8) according to the received temperature signal.

3. A radio frequency signal generator for radio frequency ablation according to claim 1 or 2, characterized in that: Also includes an isolation circuit I (3) and an isolation circuit II (9); The main control module (4) is connected to the VIP measurement module (6), the temperature measurement module (7), the DDS module (2) and the linear power amplifier and impedance matching module (8) via an isolation circuit I (3); The VIP measurement module (6), the temperature measurement module (7) and the linear power amplifier and impedance matching module (8) are connected to the ablation catheter and the negative electrode plate via an isolation circuit II (9).

4. The radio frequency signal generator for radio frequency ablation according to claim 3, characterized in that: It also includes a display module (5), and the main control module (4) sends the frequency, amplitude and phase of the required radiofrequency ablation signal and the voltage, current and phase signal of the feedback signal monitored by the VIP measurement module (6) to the display module (5); The display module (5) is used to display the received signal.

5. The radio frequency signal generator for radio frequency ablation according to claim 4, characterized in that: The display module (5) is also used to display warning signals.

6. The radio frequency signal generator for radio frequency ablation according to claim 4, characterized in that: The linear power amplifier and impedance matching module (8) comprises two transistors T1 and T2, three resistors Rd1, Rd2 and Rs, an inductor coil L, and an impedance matching group; The radiofrequency ablation signal is input to the gate of transistor T1, the source of transistor T1 is connected to the ground through resistor Rs, and the drain is connected to the power supply V through resistor Rd1. DD , the drain of transistor T1 is also connected to the source of transistor T2; V GG To provide a static operating point voltage to the gate of transistor T2, the drain of T2 is connected to one end of the primary coil of inductor L, and the other end of the primary coil of inductor L is connected to the power supply V through resistor Rd2. DD ; One end of the secondary coil of the inductor L is connected to the electrical signal input end of the ablation catheter through an impedance matching group; The other end of the secondary coil of the inductor L is connected to the negative plate through an impedance matching group.

7. A radio frequency signal generator for radio frequency ablation according to claim 1 or 2, characterized in that: It also includes an AC-DC isolated power supply (1), wherein the AC-DC isolated power supply (1) is used to supply power to the DDS module (2).

8. The radio frequency signal generator for radio frequency ablation according to claim 1, characterized in that: The impedance threshold range is: 50Ω to 250Ω.

Images