Multifunctional cavitation detection and excitation device

Abstract

The invention relates to the technical field of ultrasonic measurement testing, in particular to a multifunctional cavitation detection and excitation device. The double-frequency single-aperture transmitting transducer at the bottom of the spherical water tank and the eight transmitting-receiving integrated focusing ultrasonic transducers around the spherical water tank are confocal, and a medium irradiated by ultrasonic is fixed in the phantom box and moved to a confocal area; the signal generator excites the double-frequency single-aperture transmitting transducer at the bottom of the spherical water tank to generate cavitation in a confocal area through the power amplifier. And single-frequency or double-frequency ultrasonic excitation can be realized through different wiring modes. The eight transmitting-receiving integrated focused ultrasonic transducers around the water tank can also realize active cavitation detection and passive cavitation detection through different wiring modes. According to the invention, active cavitation detection and passive cavitation detection under different ultrasonic cavitation excitation modes can be realized under the same device, the operation is convenient, the measurement efficiency and accuracy are improved, and real-time accurate detection of cavitation is flexibly realized according to different actual conditions.

Description

Technical Field

[0001] The invention relates to the technical field of ultrasonic measurement and testing, and in particular to a multifunctional cavitation detection and excitation device. Background Art

[0002] High-intensity focused ultrasound (HIFU) therapy is an emerging non-invasive technology that is widely used in the field of tumor treatment. Its basic principle is to use high-intensity ultrasonic energy to focus on specific target tissues through focusing, resulting in local temperature increase, thereby achieving thermal ablation of tissues or stimulating biological responses. Its advantages are that it is non-invasive, has a short recovery period, has little damage to surrounding tissues, is easy to operate, and can be treated repeatedly.

[0003] During high-intensity focused ultrasound (HIFU) treatment, the occurrence of cavitation has important clinical significance, however, its potential risks cannot be ignored. The phenomenon that tiny bubbles in liquid or tissue continue to oscillate or expand and contract to collapse under the action of appropriate ultrasound is called ultrasonic cavitation. The bursting of cavitation bubbles can lead to a sudden increase in local temperature, causing excessive thermal damage to the target tissue, leading to cell death and tissue necrosis. This thermal damage is not limited to the target tissue, but may also affect the surrounding healthy tissue, causing unnecessary side effects. The cavitation process may be accompanied by the generation of sound waves, which can cause mechanical damage to surrounding cells when propagating in the tissue, increasing the risk of treatment. In addition, the frequency and intensity of cavitation are closely related to the parameters of ultrasound. Improper treatment settings may induce excessive cavitation, thereby increasing the possibility of complications.

[0004] Therefore, real-time monitoring and control of cavitation is crucial during HIFU treatment to ensure the improvement of treatment plans and the safety and effectiveness of the treatment process. Active cavitation detection (ACD) and passive cavitation detection (PCD) can be used to detect cavitation activity in real time. The implementation of an effective cavitation detection mechanism can identify and control these risks in a timely manner to ensure patient safety. In summary, active and passive cavitation detection of tissues under focused ultrasound has broad application prospects and great potential in medicine and biology. Summary of the invention

[0005] In view of this, the present invention designs a multifunctional cavitation detection and excitation device, which can excite cavitation under the action of single-frequency or dual-frequency ultrasound and realize active cavitation detection and passive cavitation detection, and improve the accuracy of cavitation measurement through multiple measurement methods.

[0006] In order to achieve the above purpose, the following technical solutions are proposed:

[0007] A spherical water tank is used to construct a spherical sound field;

[0008] Eight integrated focused ultrasonic transducers are fixed around the spherical water tank at 45° intervals and focused on the same focal area to output or receive low-power ultrasonic waves.

[0009] A dual-frequency single-aperture transmitting transducer is a dual-frequency confocal composite transducer made by cutting a concave spherical piezoelectric ceramic wafer into two transducers in concentric circles. It is fixed at the bottom of the spherical water tank and is used to output high-power ultrasonic waves to excite cavitation and focus them in the focal area to achieve confocality with eight integrated transceiver focused ultrasonic transducers.

[0010] A transducer fixing device, connected to the eight integrated transceiver focused ultrasonic transducers, and used to fix the eight integrated transceiver focused ultrasonic transducers;

[0011] An XYZ multi-axis linear slide, connected to the phantom box, and used to move the phantom box to the focal area of ​​the transducer;

[0012] A phantom box, connected to the XYZ multi-axis linear slide, is used to fix the phantom irradiated by ultrasound;

[0013] Aluminum profile, connected with the dual-frequency single-aperture transmitting transducer, the transducer fixture and the XYZ multi-axis linear slide, used to support the entire device;

[0014] The moving pulley is connected to the aluminum profile and is used to move the entire device;

[0015] Two signal generators, one signal generator is connected to eight integrated focused ultrasonic transducers for transmitting detection signals during active cavitation detection, and the other signal generator is connected to a dual-frequency single-aperture transmitting transducer after being connected to a power amplifier for exciting cavitation. The signal generator can generate a continuous sine wave signal or a pulse signal to excite the transducer to focus the sound field on a common focal area;

[0016] A power amplifier, connected to the signal generator, is used to amplify the power of the input signal to drive the transducer to generate high-intensity ultrasonic excitation cavitation;

[0017] An acquisition card connected to eight focused ultrasonic transducers with integrated transmitter and receiver functions, and used to receive acoustic signals within the focus area;

[0018] The computer is connected to the acquisition card and is used to analyze the sound signal received by the acquisition card and extract the cavitation information in the sound signal to determine whether cavitation occurs.

[0019] Compared with the current conventional methods, the beneficial effects of the present invention are as follows: the present invention proposes a multifunctional cavitation detection and excitation device. In terms of cavitation excitation, single-frequency excitation cavitation can be used, and more efficient dual-frequency excitation cavitation can also be used. The emission power and emission mode of the focusing transducer can be flexibly adjusted by adjusting the signal generator and the power amplifier. In cavitation detection, active cavitation detection and passive cavitation detection can be flexibly used to analyze the cavitation conditions of various phantoms by fixing different phantoms in a phantom box according to actual conditions, providing help for cavitation-related research. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are only used to provide further understanding of the present invention and do not constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation of the present invention.

[0021] Figure 1 It is a schematic diagram of the main body of the device;

[0022] Figure 2 This is the principle diagram of active cavitation detection;

[0023] Figure 3 This is the schematic diagram of passive cavitation monitoring.

[0024] Figure 4 Schematic diagram of the phantom box

[0025] Explanation of the reference numerals: 1. XYZ multi-axis linear slide; 2. Phantom box; 3. Spherical water tank; 4. Eight integrated focused ultrasonic transducers for transmitting and receiving; 5. Transducer fixing device; 6. Dual-frequency single-aperture transmitting transducer; 7. Aluminum profile; 8. Moving pulley. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with specific implementation modes and accompanying drawings.

[0027] in Figure 1 This is a schematic diagram of the entire multifunctional cavitation detection and excitation device. The main body of the device includes a spherical water tank, eight integrated focused ultrasonic transducers, a dual-frequency single-aperture transmitting transducer, a transducer fixing device, an XYZ multi-axis linear slide, a phantom box, an aluminum profile, and a moving pulley.

[0028] The specific process of active cavitation detection is as follows:

[0029] Step 1: Connect the signal generator to the power amplifier and then to the dual-frequency single-aperture transmitting transducer at the bottom of the spherical water tank. In dual-frequency transmission, the two transmitting ends of the signal generator need to be connected to a power amplifier and two piezoelectric ceramics of the dual-frequency single-aperture transmitting transducer respectively. In single-frequency transmission, only the signal generator needs to be connected to the power amplifier and one piezoelectric ceramic of the dual-frequency single-aperture transmitting transducer.

[0030] Step 2: Fix the phantom on the phantom box and move the phantom box to the transducer confocal area

[0031] Step 3: Connect the signal generator to the three focused ultrasonic transducers on one side of the water tank as transmitting transducers to emit low-power detection signals

[0032] Step 4: Excite the dual-frequency single-aperture transmitting transducer at the bottom of the water tank to induce cavitation in the phantom. The acquisition card is connected to the three focused ultrasonic transducers on the other side of the water tank as receiving transducers to receive the detection signal. The computer determines whether cavitation occurs by detecting the attenuation of the signal amplitude or the enhancement of high-order harmonics.

[0033] The specific process of passive cavitation detection is as follows:

[0034] Step 1: Connect the signal generator to the power amplifier and then to the dual-frequency single-aperture transmitting transducer at the bottom of the spherical water tank. In dual-frequency transmission, the two transmitting ends of the signal generator need to be connected to a power amplifier and two piezoelectric ceramics of the dual-frequency single-aperture transmitting transducer respectively. In single-frequency transmission, only the signal generator needs to be connected to the power amplifier and one piezoelectric ceramic of the dual-frequency single-aperture transmitting transducer.

[0035] Step 2: Fix the phantom on the phantom box and move the phantom box to the transducer confocal area

[0036] Step 3: Excite the dual-frequency single-aperture transmitting transducer at the bottom of the water tank to induce cavitation in the phantom. The acquisition card is connected to 8 or any number of focused ultrasonic transducers around the water tank to receive the detection signal. The computer determines whether cavitation occurs by detecting the subharmonics of the signal, the appearance of broadband noise, or the enhancement of the amplitude of the difference frequency signal under the action of dual frequencies.

[0037] In some examples of the present invention, a human tissue phantom can be used as a medium for cavitation detection. The raw materials of the human tissue phantom are 40% acrylamide solution, egg white, 10% ammonium persulfate solution, methylenebisacrylamide, degassed water with an oxygen content of 0.1 mg / L, and tetramethylethylenediamine. The phantom has high transparency, and the sound velocity and sound attenuation coefficient are similar to those of the human body. When the phantom is irradiated with focused ultrasound and the temperature exceeds a certain temperature, the egg white, as a temperature indicator, will present an opaque milky white color, and the change is irreversible. This is because the egg white undergoes protein coagulation when heated, which is conducive to directly observing HIFU irradiation.

[0038] The preparation method of the simulated human tissue is as follows:

[0039] 1. When the total dosage is 150 ml, first take 44.5% by volume of deaerated water, then add 24.8% by volume of acrylamide solution and 0.5% by volume of ammonium persulfate solution and fully dissolve them.

[0040] 2. Add 30% by volume of fresh egg white and mix by centrifuge;

[0041] 3. Place the mixed liquid into a degassing pump and degas for 1 hour;

[0042] 4. After adding 0.2% by volume tetramethylethylenediamine solution, quickly pour it into the mold and take it out after cooling and solidification.

[0043] In some examples of the present invention, the dual-frequency single-aperture transmitting transducer is manufactured by cutting a concave spherical piezoelectric ceramic wafer into two transducers in concentric circles to form a dual-frequency confocal composite transducer, which can transmit at dual frequencies or act at a single frequency.

[0044] In some examples of the present invention, the geometric focal length of the eight integrated transceiver focused ultrasonic transducers is 150 mm, the resonant frequency is 61 kHz, and the focal range (-3dB) is an ellipsoidal region with a major axis of 31 mm and a minor axis of 5 mm.

[0045] In some examples of the present invention, the dual-frequency single-aperture transmitting transducer has a geometric focal length of 200 mm, a resonant frequency of 1.15 MHz, and a focal region (-3 dB) of an ellipsoidal region with a major axis of 25 mm and a minor axis of 3 mm.

[0046] In some embodiments of the present invention, the phantom box is composed of five acrylic plates and a plastic rod, and the plastic rod is fixed to the XYZ multi-axis linear slide with screws. Figure 4 shown.

[0047] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A multifunctional cavitation detection and excitation device, which can excite cavitation under the action of single-frequency or dual-frequency ultrasound and realize active cavitation detection and passive cavitation detection, characterized in that: include: A spherical water tank is used to construct a spherical sound field; Eight integrated focused ultrasonic transducers are fixed around the spherical water tank at 45° intervals and focused on the same focal area to output or receive low-power ultrasonic waves. A dual-frequency single-aperture transmitting transducer, fixed at the bottom of the spherical water tank, is used to output single-frequency or dual-frequency high-power ultrasonic waves to excite cavitation and achieve co-focusing with the focal area of ​​eight integrated transceiver focused ultrasonic transducers; A transducer fixing device, connected to the eight integrated transceiver focused ultrasonic transducers, and used to fix the eight integrated transceiver focused ultrasonic transducers; An XYZ multi-axis linear slide, connected to the phantom box, and used to move the phantom box to the focal area of ​​the transducer; A phantom box, connected to the XYZ multi-axis linear slide, is used to fix the phantom irradiated by ultrasound; Aluminum profile, connected to the transducer fixture and the XYZ multi-axis linear slide, used to support the entire device; The moving pulley is connected to the aluminum profile and is used to move the entire device; Two signal generators, one signal generator is connected to eight integrated focused ultrasonic transducers for transmitting detection signals during active cavitation detection, and the other signal generator is connected to a dual-frequency single-aperture transmitting transducer after being connected to a power amplifier for exciting cavitation. The signal generator can generate a continuous sine wave signal or a pulse signal to excite the transducer to focus the sound field on a common focal area; A power amplifier, connected to the signal generator, is used to amplify the power of the input signal to drive the transducer to generate high-intensity ultrasonic excitation cavitation; An acquisition card connected to eight focused ultrasonic transducers with integrated transmitter and receiver functions, for receiving acoustic signals within the focus area; The computer is connected to the acquisition card and is used to analyze the acoustic signal obtained by the acquisition card and extract cavitation information from the acoustic signal to determine whether cavitation occurs.

2. A multifunctional cavitation detection and excitation device as claimed in claim 1, characterized in that: The dual-frequency ultrasonic action to excite cavitation requires that the two transmitting ends of the signal generator be connected to a power amplifier respectively and then connected to two piezoelectric ceramics of the dual-frequency single-aperture transmitting transducer for excitation.

3. A multifunctional cavitation detection and excitation device as claimed in claim 1, characterized in that: The single-frequency ultrasonic action to excite cavitation requires connecting the signal generator to a power amplifier and then to any one of the piezoelectric ceramics in the dual-frequency single-aperture transmitting transducer for excitation.

4. A multifunctional cavitation detection and excitation device as claimed in claim 1, characterized in that: The active cavitation detection can be achieved by using an XYZ multi-axis linear slide to move the phantom where cavitation is required to be generated to the transducer confocal area, a signal generator excites the dual-frequency single-aperture transmitting transducer at the bottom of the water tank through a power amplifier to stimulate cavitation, a signal generator is connected to three focused ultrasonic transducers on one side of the water tank to emit a low-power detection signal, an acquisition card is connected to three focused ultrasonic transducers on the other side of the water tank to receive the detection signal, and a computer determines whether cavitation is generated by detecting the attenuation of the signal amplitude or the enhancement of high-order harmonics.

5. A multifunctional cavitation detection and excitation device as claimed in claim 1, characterized in that: The passive cavitation detection can be realized by using an XYZ multi-axis linear slide to move the phantom where cavitation is to be generated to the transducer confocal area, a signal generator excites the dual-frequency single-aperture transmitting transducer at the bottom of the water tank through a power amplifier to stimulate cavitation, an acquisition card is connected to eight or any number of focused ultrasonic transducers in the water tank to receive detection signals, and a computer determines whether cavitation is generated by receiving subharmonics and broadband noise of the acoustic signal. Under the action of dual frequencies, it can also determine whether cavitation is generated by the change in the difference frequency amplitude.

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