A circuit and method for determining the contact between an ultrasound therapy system and tissue.

Abstract

This invention discloses a circuit and method for determining contact between an ultrasound therapy system and tissue. The circuit for determining contact between the ultrasound therapy system and tissue includes a common-mode inductor, a diode detection circuit, and a microcontroller unit. The two pins of the first side of the common-mode inductor are electrically connected to the output of an impedance matching circuit and the input of a transducer, respectively. The diode detection circuit is electrically connected to the second side of the common-mode inductor, and the microcontroller unit is electrically connected to the diode detection circuit. The circuit for determining contact between the ultrasound therapy system and tissue in this invention provides a relatively short determination time, enabling timely detection of whether the transducer in the ultrasound therapy system is in contact with tissue. This avoids damage to the transducer due to excessive temperature rise caused by prolonged determination time. Furthermore, this circuit for determining contact between the ultrasound therapy system and tissue has lower cost and better accuracy and stability.

Description

Technical Field

[0001] This invention belongs to the field of medical device technology, and in particular relates to a circuit and method for determining the contact between an ultrasound therapy system and tissue. Background Technology

[0002] When using ultrasound for human therapy, the ultrasound transducer must be in full contact with the human tissue, and a coupling agent must be placed between them. This ensures that the energy emitted by the ultrasound can be coupled into the human tissue efficiently. If no coupling agent is applied or the contact is insufficient, the ultrasound energy emitted by the transducer cannot be dissipated, generating a large amount of heat at the interface between the transducer and the air. This wastes ultrasound energy, reduces the transducer's lifespan, and makes it more susceptible to damage from high temperatures.

[0003] Currently, most ultrasound therapy devices or systems use a temperature sensor embedded deep within the transducer's metal components to detect temperature rise. When the transducer is not in contact with human tissue, or is in contact with human tissue but without coupling agent, its surface temperature rises sharply. In this case, the start or stop of ultrasound emission can be determined by judging the rate of temperature rise or setting a temperature threshold. However, this approach has a long time delay. From the time the transducer leaves the skin tissue until the temperature rise detected by the temperature sensor reaches the specified rate of rise or threshold, several seconds or even tens of seconds are required. During this period, the temperature rise in the core area of ​​the transducer has already exceeded the set threshold, which can still cause some damage to the transducer.

[0004] Meanwhile, as a component carrying high-frequency and high-voltage signals, the ultrasonic transducer has a limited lifespan. If it fails to contact human tissue to emit ultrasonic beams during use, the effective lifespan of the transducer will be significantly reduced due to the excessively long detection time. Summary of the Invention

[0005] This invention provides a circuit for determining the contact between an ultrasound therapy system and tissue, aiming to solve the problem that the lifespan of transducers in existing ultrasound therapy systems is greatly reduced due to the excessive time spent determining whether they are in contact with human tissue.

[0006] This invention provides a circuit for determining contact between an ultrasound therapy system and tissue. The ultrasound therapy system includes an excitation circuit, an impedance matching circuit electrically connected to the excitation circuit, and a transducer electrically connected to the impedance matching circuit. The circuit for determining contact between the ultrasound therapy system and tissue includes a common-mode inductor, a diode detection circuit, and a microcontroller unit. Two pins on the first side of the common-mode inductor are electrically connected to the output terminal of the impedance matching circuit and the input terminal of the transducer, respectively. The diode detection circuit is electrically connected to the second side of the common-mode inductor, and the microcontroller unit is electrically connected to the diode detection circuit. The common-mode inductor is used to acquire the excitation waveform output by the impedance matching circuit and transmit the excitation waveform to the diode detection circuit. The diode detection circuit is used to convert the received excitation waveform into an envelope signal and transmit the envelope signal to the microcontroller unit. The microcontroller unit is used to compare the waveform amplitude value of the received envelope signal with a preset waveform amplitude value and determine whether the ultrasound therapy system is in contact with tissue.

[0007] Furthermore, the diode detection circuit includes a first resistor, a first capacitor, a diode, a second resistor, a third resistor, a fourth resistor, a fifth resistor, and a second capacitor. The first terminal of the first resistor is electrically connected to one pin of the second side of the common-mode inductor. The first terminal of the first capacitor is electrically connected to the second terminal of the first resistor. The anode of the diode is electrically connected to the second terminal of the first capacitor. The first terminal of the second resistor is electrically connected to the cathode of the diode. The first terminal of the third resistor is electrically connected to the first terminal of the first capacitor. The first terminal of the fourth resistor is electrically connected to the anode of the diode. The first terminal of the fifth resistor is electrically connected to the first terminal of the second resistor. The first terminal of the second capacitor is electrically connected to the first terminal of the second resistor. The second terminals of the third, fourth, fifth, and second capacitors are all grounded. The other pin of the second side of the common-mode inductor is grounded. The sampling pin of the microcontroller unit is electrically connected to the second terminal of the second resistor.

[0008] Furthermore, the capacitance value of the second capacitor is greater than the capacitance value of the first capacitor.

[0009] The present invention also provides a method for determining contact between an ultrasound therapy system and tissue, comprising the following steps:

[0010] S1. Obtain the excitation waveform output by the impedance matching circuit through the common-mode inductor, and transmit the excitation waveform to the diode detection circuit;

[0011] S2. The received excitation waveform is converted into an envelope signal by the diode detection circuit, and the envelope signal is transmitted to the microcontroller unit.

[0012] S3. The microcontroller unit compares the received envelope signal waveform amplitude value with a preset waveform amplitude value:

[0013] If the waveform amplitude value of the envelope signal is less than or equal to the preset waveform amplitude value, it is determined that the ultrasound treatment system is in contact with the tissue.

[0014] If the waveform amplitude value within the envelope signal is greater than the preset waveform amplitude value, it is determined that the ultrasound treatment system is not in contact with the tissue.

[0015] Furthermore, if the waveform amplitude value within the envelope signal is greater than or equal to the preset waveform amplitude value, the method further includes the following steps:

[0016] S4. The output of the excitation circuit is turned off by the microcontroller unit.

[0017] Furthermore, in step S1, before obtaining the excitation waveform output by the impedance matching circuit through the common-mode inductor, the excitation circuit excites for 100µs and transmits the excitation signal generated by the excitation circuit to the transducer through the impedance matching circuit. The excitation circuit stops exciting after 100µs.

[0018] Furthermore, in step S3, before the microcontroller compares the waveform amplitude value of the received envelope signal with the preset waveform amplitude value, the microcontroller waits for the excitation circuit to stop excitation for 70µs before receiving the envelope signal transmitted by the diode detection circuit.

[0019] The beneficial effects achieved by this invention are as follows: By adding a common-mode inductor, a diode detection circuit, and a microcontroller to the ultrasound therapy system, the excitation waveform can be obtained through the common-mode inductor. Then, the excitation waveform is converted into an envelope signal through the diode detection circuit. Finally, the microcontroller compares the waveform amplitude value within the envelope signal with the expected amplitude value to determine whether the ultrasound therapy system is in contact with the tissue. This method of determining contact through waveform amplitude is relatively quick and can promptly determine whether the transducer in the ultrasound therapy system is in contact with the tissue, avoiding damage to the transducer due to excessive temperature rise caused by excessively long determination time. At the same time, the circuit for determining whether the ultrasound therapy system is in contact with the tissue has lower cost and better determination accuracy and stability. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the module connection of a circuit for determining the contact between an ultrasound therapy system and tissue, provided in an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the connection between the diode detection circuit and the corresponding module in a circuit for determining the contact between an ultrasound therapy system and tissue, provided in an embodiment of the present invention.

[0022] Figure 3 This is a flowchart illustrating the steps of a method for determining contact between an ultrasound therapy system and tissue, as provided in an embodiment of the present invention.

[0023] Figure 4 This is a schematic diagram illustrating the implementation process of a method for determining contact between an ultrasound therapy system and tissue, provided in an embodiment of the present invention.

[0024] The components include: 1. Excitation circuit; 2. Impedance matching circuit; 3. Transducer; 4. Common mode inductor; 5. Diode detection circuit; and 6. Microcontroller unit. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0027] It should be noted that when one element is considered to be "connected" to another element, it can be directly connected to the other element or connected to the other element through an intermediary element. In the following embodiments, "connection" should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have the transmission of electrical signals or data between them.

[0028] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Furthermore, the terms used in this specification include any and all combinations of the associated listed items.

[0029] Example 1

[0030] This invention provides a circuit for determining contact between an ultrasound therapy system and tissue, combined with... Figure 1 and Figure 2As shown, the ultrasound therapy system includes an excitation circuit 1, an impedance matching circuit 2 electrically connected to the excitation circuit 1, and a transducer 3 electrically connected to the impedance matching circuit 2. The circuit for determining the contact between the ultrasound therapy system and the tissue includes a common-mode inductor 4, a diode detection circuit 5, and a microcontroller 6. The two pins on the first side of the common-mode inductor 4 are electrically connected to the output terminal of the impedance matching circuit 2 and the input terminal of the transducer 3, respectively. The diode detection circuit 5 is electrically connected to the second side of the common-mode inductor 4, and the microcontroller 6 is electrically connected to the diode detection circuit 5.

[0031] The common-mode inductor 4 is used to acquire the excitation waveform output by the impedance matching circuit 2 and transmit the excitation waveform to the diode detection circuit 5. The diode detection circuit 5 is used to convert the received excitation waveform into an envelope signal and transmit the envelope signal to the microcontroller 6. The microcontroller 6 is used to compare the waveform amplitude value of the received envelope signal with the preset waveform amplitude value and determine whether the ultrasound treatment system is in contact with the tissue.

[0032] The microcontroller unit 6 acquires the envelope signal through its ADC sampling pin. That is, the microcontroller unit 6 samples the envelope signal through its ADC sampling pin, and at the same time, it acquires the waveform amplitude value of the envelope signal.

[0033] Excitation circuit 1 is also called ultrasonic excitation circuit, impedance matching circuit 2 is also called impedance circuit, transducer 3 is also called ultrasonic transducer 3, common mode inductor 4 can also be represented by the symbol "L", and micro control unit 6 is also called MCU.

[0034] Specifically, the diode detection circuit 5 includes a first resistor R1, a first capacitor C1, a diode D, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a second capacitor C2. The first end of the first resistor R1 is electrically connected to one of the pins of the second side of the common-mode inductor 4. The first end of the first capacitor C1 is electrically connected to the second end of the first resistor R1. The anode of the diode D is electrically connected to the second end of the first capacitor C1. The first end of the second resistor R2 is electrically connected to the cathode of the diode D. The first end of the third resistor R3 is electrically connected to the first end of the first capacitor C1. The first end of the fourth resistor R4 is electrically connected to the anode of the diode D. The first end of the fifth resistor R5 is electrically connected to the first end of the second resistor R2. The first end of the second capacitor C2 is electrically connected to the first end of the second resistor R2. The second ends of the third resistor R3, the fourth resistor R4, the fifth resistor R5, and the second capacitor C2 are all grounded. The other pin of the second side of the common-mode inductor 4 is grounded. The sampling pin of the microcontroller unit 6 is electrically connected to the second end of the second resistor R2.

[0035] Among them, the two pins on the first side of the common mode inductor 4 are pin 1 and pin 3, the two pins on the second side of the common mode inductor 4 are pin 2 and pin 4, the input terminals are pin 1 and pin 2, and the output terminals are pin 3 and pin 4.

[0036] In this embodiment, in the common mode inductor 4, the first pin is electrically connected to the impedance matching circuit 2, the second pin is electrically connected to the first end of the first resistor R1, the third pin is electrically connected to the transducer 3, and the fourth pin is grounded.

[0037] The working principle of the circuit that determines the contact between the ultrasound therapy system and the tissue is as follows: When the transducer 3 comes into contact with the human body through the coupling agent, its output impedance will change, which will cause the amplitude of the excitation waveform of the transducer 3 to change. Therefore, as long as the voltage waveform (referred to as the excitation waveform) of the excitation voltage output to the transducer 3 by the impedance matching circuit 2 is tracked and analyzed according to the amplitude change characteristics of the excitation waveform, it can be determined whether the transducer 3 is in contact with the human tissue.

[0038] When transducer 3 is not in contact with human tissue or when the human tissue is coated with coupling agent, most of the final contact area of ​​transducer 3 is in contact with air. At this time, the impedance of transducer 3 is relatively large, the amplitude of its excitation waveform is relatively high, and the waveform amplitude value of the corresponding envelope signal will also be relatively high. When the final contact surface is in contact with human tissue, its impedance will decrease, the corresponding power will increase, but the waveform amplitude value will decrease. Therefore, the waveform amplitude value of the envelope signal can also be used to determine whether it is in contact with human tissue through coupling agent.

[0039] Based on the above principle, this embodiment connects a common-mode inductor 4 in series between the impedance matching circuit 2 and the transducer 3. The common-mode inductor 4 converts the excitation voltage waveform between the impedance matching circuit 2 and the transducer 3 into an excitation waveform. Then, the diode detection circuit 5 performs detection processing to extract the signal amplitude envelope of the excitation waveform, thereby obtaining the envelope signal, and sampling according to an appropriate timing sequence. Finally, the microcontroller unit 6 compares the waveform amplitude value of the envelope signal with the preset waveform amplitude value to determine the amplitude of the excitation waveform of the transducer 3, and thus determine whether the transducer 3 is in contact with human tissue.

[0040] The preset waveform amplitude value is the waveform amplitude value when the transducer 3 comes into contact with human tissue.

[0041] Specifically, this embodiment adds a common-mode inductor 4, a diode detection circuit 5, and a microcontroller 6 to the ultrasound therapy system. The common-mode inductor 4 acquires the excitation waveform, the diode detection circuit 5 converts the excitation waveform into an envelope signal, and the microcontroller 6 compares the waveform amplitude value within the envelope signal with the expected amplitude value to determine whether the ultrasound therapy system is in contact with the tissue. This method of determining contact through waveform amplitude is relatively quick, allowing for timely detection of whether the transducer 3 in the ultrasound therapy system is in contact with the tissue. This avoids damage to the transducer 3 due to excessive temperature rise caused by prolonged detection time. Furthermore, this circuit for determining contact between the ultrasound therapy system and the tissue has lower cost and better accuracy and stability.

[0042] Furthermore, the capacitance of the second capacitor C2 is greater than that of the first capacitor C1.

[0043] In the actual implementation, due to the large amplitude of the excitation waveform, even after processing by the diode detection circuit 5, a small-amplitude high-frequency signal will still be superimposed on the envelope signal. If not processed, it will affect the sampling value of the ADC sampling pin of the microcontroller 6, ultimately affecting the contact judgment. The traditional method is to use an operational amplifier for low-pass filtering. However, in actual implementation, even with the addition of a low-pass filter, it is still impossible to filter out the high-frequency signal. Therefore, in this embodiment, the excitation waveform is stabilized by increasing the capacitance value of the second capacitor C2. Even if the excitation stops, the output amplitude of the diode detection circuit 5 will not change by more than 10mV within 100us. In this way, the waveform amplitude value of the current envelope signal can be sampled within 100us after the excitation stops. Since there is no excitation during this period, there is no high-frequency noise on the envelope signal, and stable and accurate sampling can be performed.

[0044] Example 2

[0045] This invention provides a method for determining contact between an ultrasound therapy system and tissue, combined with... Figures 1 to 3 As shown, it includes the following steps:

[0046] S1. Obtain the excitation waveform output by the impedance matching circuit 2 through the common-mode inductor 4, and transmit the excitation waveform to the diode detection circuit 5.

[0047] S2. The received excitation waveform is converted into an envelope signal by the diode detection circuit 5, and the envelope signal is transmitted to the microcontroller unit 6.

[0048] S3. The microcontroller unit 6 compares the received envelope signal waveform amplitude value with a preset waveform amplitude value:

[0049] If the waveform amplitude value of the envelope signal is less than the preset waveform amplitude value, it is determined that the ultrasound treatment system is in contact with the tissue.

[0050] If the waveform amplitude value within the envelope signal is greater than or equal to the preset waveform amplitude value, it is determined that the ultrasound treatment system is not in contact with the tissue.

[0051] In this embodiment, the method for determining contact between the ultrasound therapy system and tissue is based on the circuit for determining contact between the ultrasound therapy system and tissue in Embodiment 1. That is, the common-mode inductor 4, the diode detection circuit 5, and the microcontroller unit 6 in this embodiment all use the corresponding devices of the circuit for determining contact between the ultrasound therapy system and tissue in Embodiment 1. Their specific functions and effects are not described in detail here.

[0052] In this embodiment, if the waveform amplitude value within the envelope signal is greater than or equal to the preset waveform amplitude value, the method further includes step S4: turning off the output of the excitation circuit 1 through the microcontroller unit 6. This allows the excitation circuit 1 to be turned off promptly when it is determined that the ultrasound therapy system is not in contact with the tissue, preventing damage to the transducer 3 due to continuous temperature rise caused by the excitation circuit 1 continuously outputting excitation signals to the transducer 3 when the transducer 3 is not in contact with human tissue.

[0053] In this embodiment, before obtaining the excitation waveform output by the impedance matching circuit 2 through the common mode inductor 4 in step S1, the excitation circuit 1 excites for 100us and transmits the excitation signal generated by the excitation circuit 1 to the transducer 3 through the impedance matching circuit 2. The excitation circuit 1 stops excitation after 100us.

[0054] The excitation circuit 1 stops excitation after 100µs and waits for the determination result before confirming whether the excitation circuit 1 should continue to output the excitation signal: if the determination result is that the transducer 3 is not in contact with the tissue, then the excitation continues to stop until the next start of the ultrasound treatment system; if the determination result is that the transducer 3 is in contact with the tissue, then the excitation circuit 1 continues to output the excitation signal.

[0055] In this embodiment, before comparing the waveform amplitude value of the received envelope signal with the preset waveform amplitude value by the microcontroller unit 6 in step S3, the microcontroller unit 6 waits for the excitation circuit 1 to stop excitation for 70µs before receiving the envelope signal transmitted by the diode detection circuit 5. This achieves delayed sampling, ensuring that the microcontroller unit 6 can stably sample the envelope signal without affecting the output power of the ultrasonic excitation.

[0056] In this embodiment, the method for determining contact between the ultrasound therapy system and tissue is performed every 1 second after the excitation circuit 1 in the ultrasound therapy system is activated. Of course, depending on actual needs, the determination can also be performed every 2 seconds, 3 seconds, 4 seconds, etc.

[0057] like Figure 4 As shown, the specific determination process for determining contact between the ultrasound therapy system and tissue is as follows: After the ultrasound therapy system is started, a determination is performed every 1 second; when a determination is performed, the excitation circuit 1 is excited for 100µs, and the excitation signal generated by the excitation circuit 1 is transmitted to the transducer 3 through the impedance matching circuit 2. The excitation circuit 1 stops excitation after 100µs; at this time, the common-mode inductor 4 converts the voltage waveform output by the excitation circuit 1 into the excitation waveform, and then the diode detection circuit 5 can collect the excitation waveform converted by the common-mode inductor 4 and convert it into the envelope signal; finally, after the excitation circuit 1 stops excitation for 70µs, the microcontroller unit 6 collects the envelope signal converted by the diode detection circuit 5 again, and compares the waveform amplitude value of the collected envelope signal with the preset waveform amplitude value to obtain a comparison result; if the comparison result exceeds the preset waveform amplitude value, the excitation circuit 1 is controlled to continue to stop excitation until the next start of the ultrasound therapy system; if the comparison result does not exceed the preset waveform amplitude value, the excitation circuit 1 is controlled to continue excitation.

[0058] Since the method for determining contact between the ultrasound therapy system and tissue in this embodiment is based on the circuit for determining contact between the ultrasound therapy system and tissue in Embodiment 1, it can also achieve the technical effect achieved by the circuit for determining contact between the ultrasound therapy system and tissue in Embodiment 1, and will not be elaborated here.

[0059] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should all be considered to be within the scope of this specification.

[0060] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A circuit for determining contact between an ultrasound therapy system and tissue, the ultrasound therapy system comprising an excitation circuit, an impedance matching circuit electrically connected to the excitation circuit, and a transducer electrically connected to the impedance matching circuit, characterized in that, The circuit for determining whether the ultrasound therapy system is in contact with tissue includes a common-mode inductor, a diode detection circuit, and a microcontroller unit. The two pins of the first side of the common-mode inductor are electrically connected to the output of the impedance matching circuit and the input of the transducer, respectively. The diode detection circuit is electrically connected to the second side of the common-mode inductor, and the microcontroller unit is electrically connected to the diode detection circuit. The common-mode inductor is used to acquire the excitation waveform output by the impedance matching circuit and transmit the excitation waveform to the diode detection circuit. The diode detection circuit is used to convert the received excitation waveform into an envelope signal and transmit the envelope signal to the microcontroller unit. The microcontroller unit is used to compare the amplitude value of the received envelope signal with a preset amplitude value and determine whether the ultrasound therapy system is in contact with tissue. The diode detection circuit includes a first resistor, a first capacitor, a diode, a second resistor, a third resistor, a fourth resistor, a fifth resistor, and a second capacitor. The first terminal of the first resistor is electrically connected to one pin of the second side of the common-mode inductor. The first terminal of the first capacitor is electrically connected to the second terminal of the first resistor. The anode of the diode is electrically connected to the second terminal of the first capacitor. The first terminal of the second resistor is electrically connected to the cathode of the diode. The first terminal of the third resistor is electrically connected to the first terminal of the first capacitor. The first terminal of the fourth resistor is electrically connected to the anode of the diode. The first terminal of the fifth resistor is electrically connected to the first terminal of the second resistor. The first terminal of the second capacitor is electrically connected to the first terminal of the second resistor. The second terminals of the third, fourth, fifth, and second capacitors are all grounded. The other pin of the second side of the common-mode inductor is grounded. The sampling pin of the microcontroller unit is electrically connected to the second terminal of the second resistor.

2. The circuit for determining contact between the ultrasound therapy system and tissue as described in claim 1, characterized in that, The capacitance value of the second capacitor is greater than the capacitance value of the first capacitor.

3. A method for determining contact between an ultrasound therapy system and tissue, applied to the circuit for determining contact between the ultrasound therapy system and tissue as described in any one of claims 1 to 2, characterized in that, The method for determining contact between the ultrasound therapy system and tissue includes the following steps: S1. Obtain the excitation waveform output by the impedance matching circuit through the common-mode inductor, and transmit the excitation waveform to the diode detection circuit; S2. The received excitation waveform is converted into an envelope signal by the diode detection circuit, and the envelope signal is transmitted to the microcontroller unit. S3. The microcontroller unit compares the received envelope signal waveform amplitude value with a preset waveform amplitude value: If the waveform amplitude value of the envelope signal is less than or equal to the preset waveform amplitude value, it is determined that the ultrasound treatment system is in contact with the tissue. If the waveform amplitude value within the envelope signal is greater than the preset waveform amplitude value, it is determined that the ultrasound treatment system is not in contact with the tissue.

4. The method for determining contact between an ultrasound therapy system and tissue as described in claim 3, characterized in that, If the waveform amplitude value within the envelope signal is greater than or equal to the preset waveform amplitude value, the following steps are also included: S4. The output of the excitation circuit is turned off by the microcontroller unit.

5. The method for determining contact between an ultrasound therapy system and tissue as described in claim 4, characterized in that, Before obtaining the excitation waveform output by the impedance matching circuit through the common-mode inductor in step S1, the excitation circuit excites for 100µs and transmits the excitation signal generated by the excitation circuit to the transducer through the impedance matching circuit. The excitation circuit stops exciting after 100µs.

6. The method for determining contact between an ultrasound therapy system and tissue as described in claim 5, characterized in that, Before comparing the received envelope signal amplitude value with the preset waveform amplitude value by the microcontroller unit in step S3, the microcontroller unit waits for the excitation circuit to stop excitation for 70µs before receiving the envelope signal transmitted by the diode detection circuit.

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