Ultrasound focal region regulation system and method for realizing focal region localization complex motion in superficial tissue

Abstract

The application discloses an ultrasonic focal region regulation system and method for realizing focal region localization of shallow tissue, which comprises a transducer, a cavity, a regulation structure, and an acoustic Fresnel zone plate (FZP). The regulation structure can reciprocate along the cavity axis under the regulation of the regulation structure, so as to regulate the focal region form of the ultrasonic wave emitted from the transducer, and then the ultrasonic wave irradiates the cells at the target position. The system can effectively regulate the focal region form of the acoustic field, so as to generate a force field acting on the tissue in the focal region, uniformly output energy, expand the action area, and improve the cell irradiation effect and safety. The complexity of the operation process of the traditional ultrasonic cell irradiation equipment is reduced, the operation frequency and difficulty are greatly reduced, the cell irradiation operator can pay more attention to the optimization of the treatment scheme, and the convenience and efficiency of the treatment are effectively improved. The high-precision acoustic field regulation technology is combined with the humanized mechanical design.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to an ultrasonic focal zone control system and method for realizing localized compound motion within superficial tissues. Background Technology

[0002] Ultrasound refers to sound waves with frequencies higher than 20kHz. It possesses advantages such as strong directionality, good penetrating power, and ease of focusing sound energy, thus finding widespread application in the medical field. Ultrasound cell irradiation equipment converts electrical energy into ultrasonic energy through a high-frequency power generator and applies it to cells via a treatment head. In in vitro clinical trials, it is often used to study the effects of ultrasound on cell permeability, proliferation, and apoptosis, evaluate the efficacy of ultrasound in tumor treatment and tissue regeneration, and verify the safety and effectiveness of ultrasound in disease treatment.

[0003] Ultrasonic cell irradiation mainly relies on its thermal effect, mechanical effect, cavitation effect, and sonochemical effect:

[0004] 1. Thermal effect: It promotes local blood circulation and metabolism by generating heat;

[0005] 2. Mechanical effect: When ultrasound propagates in a medium, it generates periodic pressure changes, affecting the cell membrane and internal structure. At the same time, the sound waves generate flow in the liquid, affecting the cell's surrounding environment and cell function through micro-vibration and massage.

[0006] 3. Cavitation effect: Inertial cavitation causes bubbles to expand and burst rapidly, generating high-energy shock waves; in addition, non-inertial cavitation causes bubbles to oscillate in the sound field, generating microfluids and shear forces.

[0007] 4. Sonochemical effect: Ultrasound generates free radicals in liquids, triggering chemical reactions. This can be used to enhance drug release and cell killing.

[0008] The effectiveness of focused ultrasound in cellular irradiation largely depends on whether its focal zone morphology meets specific requirements. An ideal focal zone is typically elongated ellipsoidal or cigar-shaped, with appropriate major-to-minor axis ratios to ensure uniform energy distribution within the target area while minimizing damage to surrounding tissues. However, existing ultrasound cellular irradiation equipment still faces the following challenges in practical applications:

[0009] The treatment depth and focal zone morphology are relatively fixed, and the treatment mode is relatively simple.

[0010] The effectiveness of cell irradiation is highly dependent on the operator's skill level, making it difficult to promote and apply the equipment.

[0011] To address these challenges, researchers have begun exploring the design of acoustic artificial structures to achieve more flexible and precise control over sound waves. Through specific geometric configurations and material properties, acoustic artificial structures can effectively regulate the propagation path and focusing effect of sound waves, thus providing new technical avenues for more precise treatment and imaging. Against this backdrop, Fresnel zone plates (FZPs), as acoustic artificial structures with unique structures and functions, have gradually become a research hotspot due to their superior capabilities in wavefront control and acoustic focusing.

[0012] Acoustic Fresnel zone plates (FZPs), as acoustic lenses based on the Fresnel diffraction principle, can achieve diverse focusing modes through precise control of sound waves, providing an effective way to solve the problem of limited treatment modes in traditional ultrasound cell irradiation equipment. Compared with traditional acoustic lenses, Fresnel zone plates have significant advantages such as flexible structure, lightweight, and low cost. By adjusting the number, thickness, width, and material parameters of the Fresnel zones, the focal length, focal zone size, and focusing efficiency of the lens can be flexibly adjusted, thereby achieving precise control of the sound field morphology. For example, research by Daniel et al. showed that optimizing the radius of the central ring of the FZP can effectively suppress side lobes and improve lateral resolution; research by Liu et al. further revealed the linear relationship between the radial width of the outermost ring of the FZP and the lateral focal spot size, providing a theoretical basis for the precise design of the focal zone morphology; Calvo et al. proposed an ultrathin FZP structure through innovative material design, significantly improving the sound field gain. These studies fully demonstrate the superior ability of Fresnel zone plates in sound field control, making them an ideal choice for achieving diverse treatment modes.

[0013] Furthermore, to reduce the difficulty of using the equipment and lessen reliance on the operator's skill level, Fresnel zone plates can be combined with miniaturized motion mechanisms to achieve dynamic changes in focal length through mechanical adjustment. This design not only avoids frequent manual adjustments found in traditional equipment but also significantly improves operational convenience and treatment efficiency. For example, by integrating micro-stepping motors or piezoelectric actuators, FZPs can achieve precise focal length adjustment within a small range, thereby adapting to treatment needs at different depths and morphologies. This semi-automated operation not only lowers the barrier to entry for the equipment but also provides technical support for the widespread application of ultrasound cell irradiation equipment.

[0014] Therefore, a focal zone control system capable of regulating the focal zone within superficial tissues is needed. Summary of the Invention

[0015] In view of this, the purpose of the present invention is to provide an ultrasonic focal zone control system for realizing localized compound motion within superficial tissues. This system utilizes the combination of acoustic Fresnel zone plates and motion mechanisms to achieve ultrasonic focal zone control.

[0016] To achieve the above objectives, the present invention provides the following technical solution:

[0017] The ultrasonic focal zone modulation system for realizing localized compound motion within superficial tissues provided by the present invention includes a transducer, a cavity, a modulation structure, and an acoustic Fresnel zone plate (FZP).

[0018] The transducer is connected to the cavity, and the acoustic Fresnel zone plate (FZP) is disposed on the cavity. The acoustic Fresnel zone plate (FZP) is disposed on the adjustment structure. Under the adjustment of the adjustment structure, it can reciprocate along the cavity axis to adjust the focal morphology of the ultrasonic waves emitted from the transducer, thereby enabling the ultrasonic waves to irradiate the cells at the target location.

[0019] Furthermore, the control structure includes a drive mechanism and an FZP clamp assembly;

[0020] The acoustic Fresnel zone plate (FZP) is mounted on the FZP clamping assembly, which is connected to a drive mechanism and moves axially along the cavity under the action of the drive mechanism.

[0021] Furthermore, the drive mechanism includes a motor and a linkage mechanism;

[0022] The motor is connected to the FZP clamp assembly via a linkage mechanism. The FZP clamp assembly is used to clamp the FZP. Under the drive of the motor, the FZP clamp assembly moves through the linkage mechanism, thereby causing the acoustic Fresnel zone plate FZP set on the FZP clamp assembly to perform periodic reciprocating motion along the axial direction in the cavity.

[0023] Furthermore, the FZP clamp assembly includes a fixing bracket and adjusting screws;

[0024] The fixing bracket is disposed on the cavity wall and is connected to the connecting mechanism. The fixing bracket is used to clamp and fix the acoustic Fresnel zone plate FZP. The adjusting screw is disposed on the fixing bracket and is used to adjust the clamping tension of the fixing bracket on the acoustic Fresnel zone plate FZP.

[0025] Furthermore, the cavity housing is provided with a graduated scale for marking the displacement of the acoustic Fresnel zone plate (FZP), and / or...

[0026] A flexible sound-permeable membrane is provided on the cavity, and a sealed cavity is formed between the flexible sound-permeable membrane and the outer shell, and degassed water is provided inside.

[0027] Furthermore, the transducer is connected via a transducer interface disposed on the cavity, and the transducer interface connection adopts a threaded connection.

[0028] Furthermore, the dimensions of the acoustic Fresnel zone plate FZP are determined according to the following formula:

[0029]

[0030] in, The total number of rings in the acoustic Fresnel zone plate. To set the focal length, λ is the wavelength of the sound wave;

[0031] This indicates the total number of rings in the acoustic Fresnel zone plates; Indicates the distance between the sound source and the zone plate; This represents the radius of each ring of the Fresnel zone plate.

[0032] Furthermore, the acoustic Fresnel zone plate FZP is a phase-reversing Fresnel zone plate, and the thickness of the phase-reversing region of the FZP makes its phase difference with the acoustic transparent region an odd multiple of Π.

[0033] Furthermore, the acoustic impedance of the flexible acoustic membrane is matched with that of human tissue, and the acoustic transmission coefficient τ of the selected material is calculated according to the following formula:

[0034]

[0035]

[0036] Where Γ is the reflection coefficient of the soft silicone zone plate; The acoustic impedance of the lens; The acoustic impedance of water; It is the imaginary unit.

[0037] The modulation method provided by this invention, utilizing the aforementioned ultrasound focal zone modulation system for achieving localized compound motion within superficial tissues, includes the following steps:

[0038] Step 1. Prepare the ultrasonic focal zone control system and set the control parameters;

[0039] Step 2. Focal Zone Morphology Adjustment

[0040] Initial focal length settings: Start the system and adjust the Fresnel zone plate to its initial position to form the default focal length configuration;

[0041] Focal domain morphology adjustment: By designing the annular structure of the Fresnel zone plate and controlling the system, the position of the zone plate in the acoustic system is changed, the phase distribution of the sound field is altered, thereby controlling the major and minor axis ratio of the focal domain.

[0042] Step 3. Focus position movement

[0043] Focus reciprocating motion: Activate the intracavitary reciprocating motion function of the Fresnel zone plate, so that the focus moves in a small range along the depth direction within the superficial tissue;

[0044] Motion parameter adjustment: Adjust the amplitude, frequency and trajectory of the focal motion to ensure uniform energy distribution and expand the effective area;

[0045] Step 4. Cell irradiation

[0046] Initiate irradiation: Activate the ultrasonic therapy gun to irradiate the cell sample;

[0047] Dynamic regulation: During irradiation, the focal morphology and focal position are dynamically adjusted based on real-time monitoring results to ensure that cells are subjected to a uniform and effective force field.

[0048] Step 5. Record and save the data.

[0049] The beneficial effects of this invention are as follows:

[0050] This invention provides an ultrasonic focal zone control system for achieving localized compound motion within superficial tissues. This system enables the generation of compound reciprocating motions within a certain range of the focal zone in superficial tissues. An acoustic Fresnel zone plate, externally connected to the treatment gun, allows for reciprocating motion within the cavity, effectively controlling the focal zone morphology (range of major and minor axes) of the sound field. Simultaneously, changes in the focal zone morphology are adjusted through localized focal point position (focal length) movement, thereby creating a changing force field effect on the tissue within the focal zone. The movement of the focal point position allows for small-range reciprocating motions at both shallow and deep locations during cell irradiation, uniformly outputting energy and expanding the treatment area. This improves the effectiveness and safety of cell irradiation. This system reduces the complexity of traditional ultrasonic cell irradiation equipment, providing an important foundation for semi-automated operation of the cell irradiation process. Operators can achieve precise stimulation and massage of the target area without frequent position changes, significantly reducing the frequency and difficulty of operations. This allows cell irradiation therapists to focus more on optimizing the treatment plan, while effectively improving the convenience and efficiency of treatment. By combining high-precision sound field control technology with user-friendly mechanical design,

[0051] The system's control structure effectively adjusts the aspect ratio of the focal zone while simultaneously enabling dynamic movement of the localized focal point (focal length) and redistribution of energy within the target area. By precisely controlling the focal zone morphology, varying force fields can be applied to the tissue within the focal zone, achieving precise mechanical stimulation of tissues at different depths and ranges. Simultaneously, the dynamic movement of the focal point allows for cyclical action between superficial and deep areas during cell irradiation, ensuring uniform energy distribution and expanding the effective treatment area. This dual control mechanism not only significantly improves the coverage and effectiveness of cell irradiation but also enhances the safety and controllability of treatment by avoiding excessively high or low local energy levels. Ultimately, this design provides an efficient, precise, and safe solution for acoustic cell irradiation, with broad application prospects.

[0052] This regulatory structure achieves a composite pattern of mechanical stimulation and uniform energy distribution in superficial tissues through the reciprocating motion of FZP and dynamic regulation of focal zone morphology. This significantly improves the coverage, therapeutic effect, and safety of cell irradiation, while reducing operational complexity. It is suitable for medical fields such as tumor treatment and tissue regeneration.

[0053] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0054] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the following drawings are provided for illustration.

[0055] Figure 1 This is a front view of the control structure.

[0056] Figure 2 To adjust the side view of the structure.

[0057] Figure 3 This is a front view of the control structure and transducer assembly.

[0058] Figure 4 This is a side view of the assembly of the control structure and the transducer.

[0059] Figure 5 This is a schematic diagram of the action applied to a cell culture dish.

[0060] Figure 6 This is a 3D printed model of a Fresnel zone plate.

[0061] Figure 7 This is a schematic diagram of the Fresnel zone plate focusing principle.

[0062] Figure 8 Flowchart of an ultrasound focal zone modulation method for achieving localized compound motion within superficial tissues.

[0063] Figure 9 This represents the variation trend of the focal length-to-minor axis ratio and focal length with the position of the Fresnel zone plate.

[0064] Figure 10 This represents the changing trends of the major and minor axes of the focal region during reciprocating motion.

[0065] In the diagram, 1 represents the control structure, 2 represents the transducer, 3 represents the cell culture dish, 4 represents the scaffold; 11 represents the motor, 12 represents the linkage system, 13 represents the FZP clamp assembly, 14 and 15 represent the fixing screws, 16 represents the acoustic Fresnel zone plate FZP, 17 represents the graduated slide rail, 18 represents the flexible acoustic membrane, and 19 represents the transducer interface. Detailed Implementation

[0066] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0067] Example 1

[0068] like Figure 1 and Figure 2 As shown, the ultrasonic focal zone control system for realizing localized compound motion within superficial tissues provided in this embodiment includes a transducer, a cavity, a control structure, and an acoustic Fresnel zone plate (FZP).

[0069] The transducer is connected to the cavity, the acoustic Fresnel zone plate (FZP) is disposed on the cavity, and the acoustic Fresnel zone plate (FZP) is disposed on the adjustment structure. Under the adjustment of the adjustment structure, it can reciprocate along the cavity axis to adjust the focal morphology (length-to-short axis ratio) of the ultrasound emitted from the transducer, thereby enabling the ultrasound to irradiate the cells at the target location.

[0070] In this embodiment, the acoustic Fresnel zone plate FZP is installed in the cavity in a movable manner that can move along the cavity axis; at the same time, the focal length-to-minor axis ratio of the ultrasonic waves emitted from the transducer can be adjusted.

[0071] The control structure in this embodiment includes a drive mechanism and an FZP clamp assembly; the acoustic Fresnel zone plate FZP is disposed on the FZP clamp assembly, the FZP clamp assembly is connected to the drive mechanism, and moves along the cavity axis under the action of the drive mechanism;

[0072] The drive mechanism in this embodiment includes a motor and a linkage mechanism;

[0073] The motor is connected to the FZP clamp assembly via a linkage mechanism. The FZP clamp assembly is used to clamp the FZP. Under the drive of the motor, the FZP clamp assembly moves through the linkage mechanism, thereby driving the acoustic Fresnel zone plate FZP set on the FZP clamp assembly to perform periodic reciprocating motion along the axial direction in the cavity. The amplitude and speed of the motion are adjustable to achieve dynamic changes in the focal zone morphology.

[0074] The FZP clamp assembly in this embodiment includes a fixed bracket and an adjusting screw;

[0075] The fixing bracket is disposed on the cavity wall and is connected to the connecting mechanism. The fixing bracket is used to clamp and fix the acoustic Fresnel zone plate FZP. The adjusting screw is disposed on the fixing bracket and is used to adjust the clamping tension of the fixing bracket on the acoustic Fresnel zone plate FZP. It is compatible with FZP of different sizes to achieve quick replacement and maintenance.

[0076] The cavity shell provided in this embodiment is provided with a scale for marking the displacement of the acoustic Fresnel zone plate (FZP); the shell is a transparent shell.

[0077] In this embodiment, a flexible acoustic membrane is provided on the cavity, and a sealed cavity is formed between the flexible acoustic membrane and the outer shell. Degassed water is provided inside, and pressure fluctuations are compensated by piston movement to ensure stable transmission of ultrasonic energy.

[0078] In this embodiment, the transducer is connected via a transducer interface disposed on the cavity, and the transducer interface connection adopts a threaded connection; it can also be an internal threaded connection.

[0079] The acoustic Fresnel zone plate (FZP) in this embodiment is used to generate interference and diffraction phenomena by setting different rings to create phase differences for different wavelengths. The FZP in this embodiment is a ring-shaped phase-reversing structure, and its ring width and phase difference are precisely designed to control the amplitude, phase, and direction of the sound wave. The FZP is made of a material with acoustic impedance close to that of human tissue, including soft silicone or vulcanized rubber, and is used to reduce sound energy attenuation and dynamically adjust the aspect ratio and focal length of the focal region. In this embodiment, the amplitude, phase, and direction of the sound wave can be controlled, and the aspect ratio of the sound field focal region can be dynamically adjusted by changing its position to achieve periodic changes in the focal region shape.

[0080] This embodiment utilizes the periodic change in the focal length-to-minor axis ratio caused by altering the relative position between the acoustic Fresnel zone plate and the sound source. As the relative position of the sound source and the Fresnel zone plate changes, this change follows a periodic pattern, resulting in corresponding periodic fluctuations in the focal length-to-minor axis ratio. The device uses a high-performance motor to drive the Fresnel zone plate in precise reciprocating motion within a preset range. This motion dynamically adjusts the relative positional relationship between the sound source and the zone plate, causing the focal length size to change periodically. This change not only affects the geometry of the focal length but also leads to a redistribution of energy within the focal length, resulting in a dynamic equilibrium.

[0081] The drive mechanism in this embodiment is used to drive the FZP clamp assembly to reciprocate, thereby achieving periodic changes in the focal length-to-minor axis ratio and dynamic adjustment of the focal length. The reciprocating motion range of the drive mechanism is 1-10mm, and the motion frequency is 0.1-5Hz. The periodic changes in the focal length-to-minor axis ratio and dynamic adjustment of the focal length are achieved by adjusting the motor parameters. The drive mechanism integrates a micro stepper motor or a piezoelectric driver and achieves millimeter-level precision displacement adjustment through a closed-loop control system.

[0082] The driving mechanism in this embodiment includes a motor and a linkage system. The motor is connected to the FZP through the linkage and drives the FZP to perform periodic reciprocating motion along the axial direction in the cavity. The amplitude and speed of the motion are adjustable to achieve dynamic changes in the focal zone morphology.

[0083] The motor is a miniature stepper motor or a piezoelectric driver. It achieves precise adjustment of the FZP's movement amplitude and frequency through closed-loop control. The focal length-to-minor axis ratio and focal length change periodically with the FZP's position.

[0084] The FZP clamp assembly in this embodiment is used to fix the position of the acoustic Fresnel zone plate FZP, securely install the FZP in the cavity, and ensure the linear accuracy of its reciprocating motion.

[0085] The FZP clamp assembly in this embodiment includes a detachable bracket and fixing screws, which can be adapted to different sizes of FZP to enable quick replacement and maintenance.

[0086] The outer shell with a graduated scale in this embodiment is a transparent structure, with the drive mechanism and FZP fixed inside. The outer shell surface is provided with a graduated scale for real-time observation and calibration of the FZP's range of motion. The graduated scale of the outer shell has an accuracy of 0.1mm, which is used to quantify the displacement of the acoustic Fresnel zone plate and correlate it with the trend of focal zone morphology changes, thereby realizing real-time optimization of treatment parameters.

[0087] In this embodiment, the scale on the outer shell is linked to the motor drive signal, and the position of FZP is adjusted through real-time feedback to optimize the treatment parameters.

[0088] Flexible acoustic membrane: Covering the front end of the shell, it is made of waterproof and pressure-resistant soft silicone material and filled with degassed water to balance the cavity pressure, ensuring that the ultrasound energy is efficiently coupled to the target tissue;

[0089] In this embodiment, a sealed cavity is formed between the flexible acoustic membrane and the outer shell. The degassed water inside compensates for pressure fluctuations through piston movement, ensuring stable transmission of ultrasonic energy.

[0090] like Figure 3 and Figure 4 As shown, in this embodiment, the control structure (including the drive mechanism and the FZP clamp assembly) is connected to the ultrasonic transducer through the transducer interface to form a complete sound field output system;

[0091] In this embodiment, the Fresnel zone plate is fixed inside the housing by a clamp, the connecting rod of the drive mechanism is mechanically connected to the clamp, the flexible acoustic membrane is sealed and installed at the front end of the housing, and the transducer interface is located at the rear end of the housing. The components work together to achieve dynamic control of the focal zone morphology and periodic reciprocating motion of the focal position.

[0092] In this embodiment, after the control structure and transducer are assembled, the long axis of the focal region fluctuates periodically with the position of the Fresnel zone plate, while the short axis remains stable, and the uniformity of the energy distribution in the focal region is improved by 20%-40%.

[0093] like Figure 5 and Figure 6 As shown, the device in this embodiment can generate complex reciprocating motions within a certain range of the focal zone in superficial tissues, placing the cell culture dish above the zone plate to achieve cell irradiation. By dynamically adjusting the aspect ratio of the focal zone, the energy distribution within the focal zone is optimized, thereby achieving a complex pattern of action on the target area during cell irradiation.

[0094] When sound waves pass through an acoustic Fresnel zone plate, sound waves of different wavelengths will interfere and diffract due to the phase difference between different rings on the zone plate.

[0095] In this embodiment, precise control of the phase difference is crucial for achieving sound wave focusing. First, the Fresnel zone plate modulates the phase and amplitude of the sound wave through alternating transparent (sound-transmitting) and opaque (sound-insulating) ring structures. The ring radius is designed based on the Fresnel zone plate formula described above. The width and position of each ring determine the phase change of the sound wave as it passes through, thus affecting the interference and diffraction behavior. When the sound wave passes through the Fresnel zone plate, different rings introduce specific phase delays or advances, thereby precisely controlling the propagation characteristics of the sound wave: transparent rings allow the sound wave to pass through with a essentially unchanged phase. Opaque rings block the sound wave, effectively introducing a π phase difference (half-wavelength delay). By alternating transparent and opaque rings, the zone plate forms a periodic phase modulation structure along the sound wave propagation path. This modulation causes the sound wave to coherently superimpose after passing through different rings, ultimately forming an enhanced sound field at the focal point. When sound waves of different wavelengths pass through the same Fresnel zone plate, different interference and diffraction effects occur due to the different relationships between wavelength and ring size. By adjusting the width and position of the zone plate, the response of the zone plate to sound waves of different wavelengths can be optimized, enabling multi-wavelength modulation or wavelength-selective focusing.

[0096] By precisely designing the annular width and phase difference of the zone plate, the amplitude, phase, and direction of sound waves can be precisely controlled, resulting in significant sound wave control capabilities and focusing effects. By changing the position of the FZP in the acoustic system, the ratio of the major and minor axes of the focal region can be controlled within a certain range, and this pattern is periodic. Therefore, this pattern can be applied to cell irradiation applications.

[0097] The structure in this embodiment is adapted to the front end of an ultrasonic transducer. Through compound reciprocating motion, it achieves dynamic force field action and uniform energy distribution in the target tissue, expanding the effective treatment area. A motor and linkage system drives the Fresnel zone plate to reciprocate within the cavity, while simultaneously adjusting the amplitude and speed of the motion. A transparent shell equipped with a graduated scale facilitates observation of the zone plate's movement range and allows for real-time optimization of treatment parameters. Waterproof and pressure-resistant soft silicone material is used for pressure compensation during piston movement within the cavity filled with degassed water, ensuring better ultrasonic coupling. This invention enables compound-mode cell irradiation of the treatment target area, reducing operator workload and improving the user experience and ease of operation of ultrasonic cell irradiation equipment.

[0098] Example 2

[0099] This embodiment further illustrates the present invention. The Fresnel zone plate (FZP) of this embodiment, as a core component, can reciprocate within the device cavity under the drive of a motor and the action of a multi-functional clamp. The acoustic Fresnel zone plate (FZP), through its precise design, enables the control of the amplitude, phase, and direction of sound waves, effectively altering the aspect ratio of the sound field's focal region. The specific parameters of the acoustic Fresnel zone plate are as follows:

[0100] like Figure 7 As shown, in practical applications, the location and depth of cell irradiation, as well as the operating frequency of the treatment head, are determined. Based on these factors, the dimensions of the Fresnel zone plate are designed. The specific design method can be found in the following expression:

[0101]

[0102] in, The total number of rings in the Fresnel zone plate. To set the focal length, λ is the wavelength of the sound wave; Indicates the distance between the sound source and the zone plate; This represents the radius of each ring of the Fresnel zone plate;

[0103] This embodiment uses a phase-reversing Fresnel zone plate, and the thickness of the phase-reversing region of the FZP makes its phase difference with the acoustically transparent region an odd multiple of Π.

[0104] Phase difference | |, , These are the sound wavenumbers of the lens and the immersion medium, respectively.

[0105] in, This indicates the phase difference between different rings; Indicates the sound wave number of the lens; This indicates the wavenumber of the sound wave into which the lens is immersed in the medium; Indicates the wavelength of the sound wave in the lens material; Indicates the wavelength of the sound wave immersed in the medium; Represents pi;

[0106] In this embodiment, the Fresnel zone plate is made of soft silicone or vulcanized rubber, and the lens thickness... The following formula can be used to calculate:

[0107]

[0108] Where q is an odd number, meaning the thickness of the lens is equal to the phase difference. An odd multiple of.

[0109] In practice, materials with acoustic impedance close to that of human tissue can be selected as zone plate materials, such as soft silicone and vulcanized rubber, which have a high transmission coefficient to reduce energy attenuation.

[0110] In this embodiment, the acoustic impedance of the flexible acoustic membrane is matched with that of human tissue. The acoustic transmission coefficient τ of the selected material can be expressed by the following expression:

[0111]

[0112] Where Γ is the reflection coefficient of the soft silicone zone plate, its value can be expressed as:

[0113]

[0114] in, Let be the acoustic impedance of the lens. The acoustic impedance of water, The imaginary unit is represented; the reflection coefficient Γ is determined by the difference between the acoustic impedance of the material and that of water.

[0115] Based on the wavefront analysis of sound waves passing through the Fresnel zone plate and the law of conservation of energy, the sound pressure function near the focal point can be obtained as follows:

[0116]

[0117] Where F is the focal length, P0 is the initial sound pressure level, and k is the wave number. (x) is a zero-order Bessel function of the first kind, used to describe the energy distribution in the focal region, η is the direction of the acoustic axis of the sound field, γ is the direction perpendicular to the acoustic axis along the radius of the zone plate, and α is the central angle formed by the maximum radius of the zone plate and the focal region. The focused sound field of the FZP in this embodiment satisfies the above sound pressure distribution function.

[0118] like Figure 8 As shown, this embodiment also provides a control method using an ultrasound focal zone control system that realizes localized compound motion within superficial tissues. The optimal effect is achieved by manipulating and changing the focal zone morphology. The specific process is as follows:

[0119] Step 1. System Preparation:

[0120] Equipment check: Ensure that the ultrasonic therapy gun, external motion device, control system, and power supply are in good working order;

[0121] Parameter settings: Based on experimental requirements, preset basic parameters such as ultrasonic frequency, power, and irradiation time;

[0122] Experimental system setup: Based on the experimental parameters, a Fresnel zone plate was designed and fixed inside the motion device to match the ultrasonic therapy gun;

[0123] Sample preparation: Fix the cell sample to be irradiated (such as a culture dish or tissue model) on the experimental stage, ensuring that it is aligned with the sound field of the ultrasound therapy gun.

[0124] Step 2. Focal Zone Morphology Adjustment

[0125] Initial focal length settings: Start the system and adjust the Fresnel zone plate to its initial position to form the default focal length configuration;

[0126] Focal domain morphology adjustment: By designing the annular structure of the Fresnel zone plate and controlling the system, the position of the zone plate in the acoustic system is changed, the phase distribution of the sound field is altered, thereby controlling the major and minor axis ratio of the focal domain.

[0127] Real-time monitoring: Use sound field detection equipment (such as a sound barometer or sound field imaging system) to monitor changes in the focal zone morphology in real time to ensure that the adjustment effect meets expectations.

[0128] Step 3. Focus position movement

[0129] Focus reciprocating motion: Activate the intracavitary reciprocating motion function of the Fresnel zone plate, so that the focus moves in a small range along the depth direction (axial direction) within the superficial tissue;

[0130] Motion parameter adjustment: Adjust the amplitude, frequency and trajectory of the focal motion according to experimental requirements to ensure uniform energy distribution and expand the effective area.

[0131] Step 4. Cell irradiation

[0132] Initiate irradiation: Activate the ultrasonic therapy gun to irradiate the cell sample;

[0133] Dynamic regulation: During irradiation, the focal morphology and focal position are dynamically adjusted based on real-time monitoring results to ensure that cells are subjected to a uniform and effective force field.

[0134] Irradiation time control: Control the irradiation time according to the experimental design to avoid overheating or insufficient energy.

[0135] Step 5. Data Recording and Analysis

[0136] Experimental data recording: Record parameters during irradiation (such as focal morphology, focal point position, sound field intensity, etc.) and cell responses (such as morphological changes, survival rate, etc.).

[0137] Results analysis: The cell irradiation effects under different focal zone morphologies and focal motion parameters were compared to optimize system parameters.

[0138] Key operational instructions in this method

[0139] 1. Focal morphology adjustment: The phase distribution of the sound field is adjusted by designing the annular structure of the Fresnel zone plate and controlling its position in the acoustic system. The focal morphology is monitored in real time to ensure that the adjustment effect meets experimental requirements.

[0140] 2. Focal Point Movement: The motion device activates the Fresnel zone plate's reciprocating motion, causing the focal point to move along the depth direction within the superficial tissue. Motion parameters (amplitude, frequency) are adjusted to optimize energy distribution. During irradiation, the focal morphology and focal point position are dynamically adjusted based on real-time monitoring results to ensure cells receive a uniform and effective force field.

[0141] This experimental method achieves dynamic control over the morphology and focal point position of the ultrasound focal zone by precisely adjusting the annular structure and motion parameters of the Fresnel zone plate, thereby optimizing cell irradiation. The experimental procedure is clear, and the operation steps are well-defined, effectively verifying the performance and application potential of the system.

[0142] Taking f=250kHz, F=12mm, and n=11 as an example, numerical simulations using COMSOL MUTIPHYSICS show that by changing the position of the acoustic Fresnel zone plate, the aspect ratio of the focal length exhibits a certain periodic variation, and the acoustic focal length also periodically varies within a certain range of the set value. Figure 9 As shown.

[0143] The designed Fresnel zone plate is embedded in the structure and fixed with clamp screws. A reciprocating motor drives the Fresnel zone plate to reciprocate within the cavity via a connecting rod. This reciprocating motion of the Fresnel zone plate causes a periodic change in the focal length-to-minor axis ratio, such as... Figure 10 As shown, the major axis of the focal region primarily causes periodic changes during positional shifts, while the minor axis of the acoustic focal region remains relatively stable. Therefore, energy is redistributed within the focal region, achieving an automatic massage effect on the target area in cell irradiation applications.

[0144] The above-described embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the claims.

Claims

1. An ultrasonic focal zone modulation system for realizing localized compound motion within superficial tissues, characterized in that: It includes a transducer, a cavity, a control structure, and an acoustic Fresnel zone plate (FZP). The transducer is connected to the cavity, the acoustic Fresnel zone plate (FZP) is disposed on the cavity, and the acoustic Fresnel zone plate (FZP) is disposed on the control structure. Under the control of the control structure, it can reciprocate along the cavity axis to adjust the focal morphology of the ultrasound waves emitted from the transducer, thereby enabling the ultrasound waves to irradiate cells at the target location.

2. The ultrasonic focal zone modulation system for realizing localized compound motion within superficial tissues as described in claim 1, characterized in that: The control structure includes a drive mechanism and an FZP clamp assembly; the acoustic Fresnel zone plate FZP is disposed on the FZP clamp assembly, the FZP clamp assembly is connected to the drive mechanism, and moves along the cavity axis under the action of the drive mechanism.

3. The ultrasonic focal zone modulation system for realizing localized compound motion within superficial tissues as described in claim 2, characterized in that: The driving mechanism includes a motor and a linkage mechanism; the motor is connected to the FZP clamp assembly through the linkage mechanism, and the FZP clamp assembly is used to clamp the FZP. Under the driving action of the motor, the FZP clamp assembly is moved through the linkage mechanism, thereby driving the acoustic Fresnel zone plate FZP set on the FZP clamp assembly to perform periodic reciprocating motion along the axial direction in the cavity.

4. The ultrasonic focal zone modulation system for realizing localized compound motion within superficial tissues as described in claim 2, characterized in that: The FZP clamping assembly includes a fixed bracket and an adjusting screw; the fixed bracket is disposed on the cavity wall and connected to the connecting mechanism, and is used to clamp and fix the acoustic Fresnel zone plate FZP; the adjusting screw is disposed on the fixed bracket and is used to adjust the clamping tension of the fixed bracket on the acoustic Fresnel zone plate FZP.

5. The ultrasonic focal zone modulation system for realizing localized compound motion within superficial tissues as described in claim 1, characterized in that: The cavity shell is provided with a scale for marking the displacement of the acoustic Fresnel zone plate (FZP), and / or a flexible acoustic membrane is provided on the cavity, forming a sealed cavity between the flexible acoustic membrane and the outer shell, with degassed water inside.

6. The ultrasonic focal zone modulation system for realizing localized compound motion within superficial tissues as described in claim 1, characterized in that: The transducer is connected via a transducer interface disposed on the cavity, and the transducer interface is connected by a threaded connection.

7. The ultrasonic focal zone modulation system for realizing localized compound motion within superficial tissues as described in claim 1, characterized in that: The dimensions of the acoustic Fresnel zone plate FZP are determined according to the following formula: in, The total number of rings in the acoustic Fresnel zone plate. To set the focal length, λ is the wavelength of the sound wave; Indicates the distance between the sound source and the zone plate; This represents the radius of each ring of the Fresnel zone plate.

8. The ultrasonic focal zone modulation system for realizing localized compound motion within superficial tissues as described in claim 1, characterized in that: The acoustic Fresnel zone plate FZP is a phase-reversing Fresnel zone plate, and the thickness of the phase-reversing region of the FZP makes its phase difference with the acoustic transparent region an odd multiple of Π.

9. The ultrasonic focal zone modulation system for realizing localized compound motion within superficial tissues as described in claim 5, characterized in that: The acoustic impedance of the flexible acoustic membrane is matched with that of human tissue, and the acoustic transmission coefficient τ of the selected material is calculated according to the following formula: Where Γ is the reflection coefficient of the soft silicone zone plate; The acoustic impedance of the lens; The acoustic impedance of water; It is the imaginary unit.

10. A method for controlling the movement using the ultrasonic focal zone control system for achieving localized compound motion within superficial tissues according to any one of claims 1-9, characterized in that: Includes the following steps: Step 1. Prepare the ultrasonic focal zone control system and set the control parameters; Step 2. Focal Zone Morphology Adjustment Initial focal length settings: Start the system and adjust the Fresnel zone plate to its initial position to form the default focal length configuration; Focal domain morphology adjustment: By designing the annular structure of the Fresnel zone plate and controlling the system, the position of the zone plate in the acoustic system is changed, the phase distribution of the sound field is altered, thereby controlling the major and minor axis ratio of the focal domain. Step 3. Focus position movement Focus reciprocating motion: Activate the intracavitary reciprocating motion function of the Fresnel zone plate, so that the focus moves in a small range along the depth direction within the superficial tissue; Motion parameter adjustment: Adjust the amplitude, frequency and trajectory of the focal motion to ensure uniform energy distribution and expand the effective area; Step 4. Cell irradiation Initiate irradiation: Activate the ultrasonic therapy gun to irradiate the cell sample; Dynamic regulation: During irradiation, the focal morphology and focal position are dynamically adjusted based on real-time monitoring results to ensure that cells are subjected to a uniform and effective force field. Step 5. Record and save the data.

Images