Intelligent acoustic lens focusing system and focusing method suitable for removing and crushing stones

Abstract

The invention discloses an intelligent acoustic lens focusing system and focusing method suitable for removing and crushing stones, and belongs to the technical field of medical ultrasound. The system comprises a B-ultrasonic module, an improved Fresnel acoustic lens, a micro-flow control module and a control calculation module, the acoustic lens is of a concentric circle structure with alternate fixed material ring belts and injectable liquid ring belts, and the liquid sound velocity is dynamically adjusted through the micro-flow control technology to achieve accurate focus control. The method comprises the following steps of: positioning a stone coordinate in real time through B-mode ultrasound, predicting a current focus position, calculating a sound path distance difference and a phase compensation amount, inversely solving an optimal liquid sound velocity and injecting the optimal liquid sound velocity into a corresponding girdle to form closed-loop focusing regulation and control. The device solves the problems of energy dispersion and response lag of traditional stone crushing equipment, has the advantages of simplified structure, high adjustment precision and adaptability to dynamic targets, and has the advantages that the focusing error can be controlled within + / -1mm, and the stone crushing efficiency is improved by more than 30%.

Description

Technical Field

[0001] This invention belongs to the field of lithotripsy technology, specifically relating to an intelligent acoustic lens focusing system and focusing method suitable for lithotripsy. This invention addresses the problems of focal deviation and energy dispersion in extracorporeal shock wave lithotripsy by achieving precise focusing through ultrasound feedback and dynamic switching of liquid materials, making it suitable for medical scenarios such as stone fragmentation. Background Technology

[0002] Currently, extracorporeal shock wave lithotripsy (ESWL) devices generally use traditional fixed-focus elements as energy focusing components. However, traditional fixed-focus lenses suffer from energy dispersion and insufficient focusing accuracy, resulting in the shock wave energy not being able to accurately target the stone, leading to low lithotripsy efficiency. Furthermore, energy dispersion may cause unnecessary damage to surrounding tissues, increasing the risk of patient complications. Existing focusing control technologies mainly include two methods: mechanical adjustment and fixed parameters. Mechanical adjustment adjusts the focus by changing the position of the lens or shock wave source, but it suffers from slow response speed, complex structure, and poor stability, making it difficult to meet the real-time and stability requirements of ESWL. Fixed parameter methods use preset fixed parameters for energy focusing, which cannot adapt to individual differences among patients or dynamic changes caused by stone movement, resulting in unstable lithotripsy effects. Therefore, to address the needs of ESWL, a variable-focus system capable of dynamically adjusting the acoustic parameters of the lens through microfluidic control is developed. This system is suitable for scenarios requiring real-time focus adjustment, such as ultrasound therapy and acoustic manipulation. It simplifies the equipment structure, improves treatment efficiency, enhances lithotripsy effects, and reduces the incidence of treatment complications. Summary of the Invention

[0003] This invention proposes an intelligent acoustic lens focusing system and focusing method suitable for lithotripsy, aiming to solve the problems of energy focusing deviation, difficulty in dynamically adjusting the focal position, and low shock wave energy utilization in existing extracorporeal shock wave lithotripsy devices. This invention can adjust the focusing position based on the target image acquired by ultrasound, thereby improving the concentration of shock wave energy and enhancing the lithotripsy effect.

[0004] The technical solution of this invention is:

[0005] A smart acoustic lens focusing system suitable for stone removal and crushing includes:

[0006] The ultrasound module is used to acquire ultrasound images of the target stone in real time and determine the spatial coordinates of the stone.

[0007] The improved Fresnel acoustic lens consists of multiple concentric rings, where the odd-numbered rings are fixed material rings and the even-numbered rings are cavities that can be independently injected with liquid;

[0008] The microfluidic control module is used to inject liquids with different sound velocities into the injectable cavity according to control commands, so as to dynamically adjust the focusing characteristics of the acoustic lens;

[0009] The control and calculation module is used to process ultrasound data, predict the current focal position, calculate the deviation between the target and the focal point, and generate liquid sound velocity adjustment commands.

[0010] The fixing material ring is made of PMMA, which has a sound velocity of 2200 m / s and a density of 1180 kg / m³. 3 ;

[0011] The injectable liquid includes water, transformer oil, or a mixture thereof, and the liquid sound velocity is adjustable from 1325 m / s to 1500 m / s.

[0012] The acoustic lens operates in a frequency range of 500kHz-1MHz and has a dynamic focal length adjustment range of 45mm-80mm.

[0013] The upper and lower surfaces of the acoustic lens are covered with a sound-transmitting film to seal the liquid cavity and ensure efficient transmission of sound waves.

[0014] The control calculation module includes a pre-trained finite element simulation model for predicting the focal position under different liquid configurations.

[0015] The microfluidic control module includes a liquid storage unit, a proportioning unit, and an injection unit, and can precisely adjust the sound velocity of the liquid in each annulus according to instructions.

[0016] A smart acoustic lens focusing method suitable for stone removal and crushing includes the following steps:

[0017] S1. Target localization: The spatial coordinates of the stone are extracted by real-time acquisition of ultrasound images of the stone via B-ultrasound.

[0018] S2, Focus Prediction: Calculate the current focus position based on the current liquid sound velocity in each annulus of the acoustic lens;

[0019] S3. Deviation Calculation: Compare the target stone location with the predicted focal location and calculate the deviation vector;

[0020] S4. Sound path difference calculation: Calculate the required sound path difference and phase compensation for each annulus based on the deviation.

[0021] S5, Liquid sound velocity regulation: Inversely calculates the required liquid sound velocity for each annulus and controls the microfluidic module to inject the corresponding liquid;

[0022] S6. Focus Verification: Re-predict the focus position and confirm whether it matches the target position. If it does not match, iterate and adjust.

[0023] In step S2, the focus prediction uses a pre-trained COMSOL finite element model, and the input parameters include the ring geometry, the liquid sound velocity, and the operating frequency.

[0024] In step S4, the formula for calculating the phase compensation amount is:

[0025]

[0026] Where f is the operating frequency, ΔL is the sound path difference, and c0 is the sound velocity of the background medium (water).

[0027] In step S5, the liquid sound velocity adjustment is based on a lookup table or real-time calculation, matching a preset liquid sound velocity-density database.

[0028] The method is applicable to extracorporeal shock wave lithotripsy and supports real-time dynamic adjustment to adapt to stone displacement or tissue deformation.

[0029] Its design principle is based on an improved Fresnel lens, which consists of multiple concentric rings. The odd-numbered rings are made of fixed material, while the even-numbered rings are designed as independent injection chambers. The local phase delay and / or energy output can be altered by injecting liquids with different sound velocities. Its working steps are as follows:

[0030] During operation, the ultrasound module acquires raw ultrasound images, uses image recognition algorithms to detect the target location in the image coordinate system, and extracts the target's physical spatial coordinates (x, y). t ,y t ,z t Mapping the image coordinates to the acoustic lens coordinate system yields a three-dimensional spatial vector. For calibration matrix;

[0031] For the current m-th ring, its speed of sound c m The coordinates are r m =(x m ,y m ,z m The pre-trained COMSOL finite element model is used to predict the current three-dimensional coordinate position r of the acoustic lens focal point. s =(x s ,y s ,z s ) portion;

[0032] Based on the target point (x) t ,y t ,z t ) and prediction focus (x) s ,y s ,z s The coordinates of the deviation vector are used to obtain the deviation magnitude. and direction angle

[0033] Further calculate the distance difference required for the m-th loop. and the corresponding phase compensation amount Where f is the operating frequency, c0 is the sound velocity of the background medium water, and k is the wave number;

[0034] Finally, the sound velocity of the liquid that needs to be increased is obtained. d m Given the height of the m-th ring, the sound velocity command is transmitted to the microfluidic control module, which injects the pre-mixed liquid into the liquid chamber corresponding to each ring, thereby completing the focus control.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] 1. The beneficial effects of intelligent acoustic lens focusing systems suitable for stone removal and crushing

[0037] (1) Dynamic precision focusing

[0038] By improving the Fresnel acoustic lens structure (alternating design of fixed material ring and injectable liquid ring) and microfluidic technology, the focal position can be dynamically adjusted in real time, overcoming the defects of energy dispersion and large focusing deviation of traditional fixed focal length lenses. The focusing accuracy can reach ±1mm, significantly improving the efficiency of shock wave lithotripsy.

[0039] (2) Structural simplification and reliability improvement

[0040] Microfluidic liquid regulation is used to replace traditional mechanical moving parts, avoiding the complexity of mechanical structures and wear problems;

[0041] The acoustically permeable membrane sealing design ensures stable acoustic performance of the liquid ring while simplifying maintenance requirements.

[0042] (3) Strong adaptability

[0043] By providing real-time feedback on the location of the stones via ultrasound, and combining this with a pre-trained finite element model (such as COMSOL) to quickly predict the focal point, the system can adapt to changes in the target point caused by stone displacement or the patient's breathing.

[0044] It supports flexible mixing ratios of liquids with different sound velocities (such as water and transformer oil), covering a focal length range of 45-80mm.

[0045] (4) Security optimization

[0046] Precise focusing reduces accidental damage of shock waves to surrounding healthy tissues, lowering the risk of complications such as hematuria and kidney damage;

[0047] A closed-loop control mechanism (positioning-calculation-adjustment-verification) ensures a stable and reliable treatment process.

[0048] 2. Beneficial effects of the intelligent acoustic lens focusing method applicable to stone removal and crushing

[0049] (1) High-efficiency closed-loop control

[0050] Through a closed-loop process of "target positioning → focus prediction → deviation calculation → liquid adjustment → focus verification", fully automatic dynamic focusing is achieved with a response time of less than 100ms, far exceeding the traditional mechanical adjustment method (which usually takes several seconds).

[0051] (2) Algorithm-driven high-precision compensation

[0052] Based on the quantitative calculation of the sound path difference (ΔL) and the phase compensation amount (Δφ), combined with the liquid sound velocity-density database, the compensation accuracy is ensured;

[0053] Pre-trained finite element models improve focus prediction efficiency and reduce real-time computational load.

[0054] (3) Compatibility and scalability

[0055] The method can be adapted to different frequencies (500kHz-1MHz) and lens sizes, and its application scenarios can be expanded by adjusting the liquid type or ring parameters;

[0056] The algorithm module supports integration with existing ultrasound equipment, reducing the cost of upgrading hospital equipment.

[0057] (4) Significant clinical benefits

[0058] Actual tests show that the system improves lithotripsy efficiency by more than 30% and shortens the single treatment cycle by 20%.

[0059] Reducing the number of repetitive impacts lowers patient pain and treatment costs.

[0060] The comprehensive advantage of this invention is that it combines innovative system structure (microfluidic acoustic lens) with intelligent control method (closed-loop algorithm), which solves the three major technical problems of energy dispersion, response lag and operation complexity in extracorporeal shock wave lithotripsy. It has high precision, high reliability and low cost clinical value, and provides an innovative solution for ultrasound precision treatment. Attached Figure Description

[0061] Figure 1 This is a schematic diagram of the acoustic lens structure of the present invention;

[0062] Figure 2 This is a cross-sectional view of the acoustic lens of the present invention;

[0063] Figure 3 This is a flowchart of the process of this invention;

[0064] Figure 4 This is a simulation diagram of the focused sound field of the present invention as it changes with the liquid. Detailed Implementation

[0065] The present invention will now be described in detail with reference to the accompanying drawings.

[0066] Figure 1 This is a schematic diagram of the adjustable acoustic lens of the present invention. It includes a substrate ring 1 and a ring 2 with an injection cavity, and the multiple rings are concentric circles; from Figure 2 It can be seen that the ring is sealed with a sound-permeable film 3 at the top and bottom, and the substrate ring 1 and the ring 2 with the injection cavity appear alternately.

[0067] Figure 3 The workflow of this invention is as follows: First, target localization: real-time acquisition of tissue images by ultrasound to obtain the spatial coordinates of the stone's location. Second, focus prediction: calculation of the actual focus position coordinates based on the sound velocity of the injected fluid in each ring of the acoustic lens. Third, deviation calculation: calculation of the deviation direction and magnitude based on the target and predicted focus positions. Fourth, calculation of the sound path difference: the target sound path minus the current sound path. Fifth, obtaining the sound velocity of the fluid to be injected into the rings through an algorithm. Finally, the sound velocity information is transmitted to the microfluidic control module, which selects the corresponding fluid according to the instructions and injects it into the lens to form a new focusing configuration.

[0068] Figure 4 This is a simulation diagram of the focused sound field as it changes with the liquid.

[0069] Example

[0070] Considering the practical needs of lithotripsy, the desired ultrasonic operating frequency range is 500kHz-1MHz, and the focal length range is 45mm-80mm. The focal length can be dynamically adjusted according to the target position feedback from the ultrasound. An acoustic lens with independent liquid injection chambers is designed, employing a concentric ring structure. The odd-numbered concentric rings are made of PMMA (polymethyl methacrylate), while the even-numbered concentric rings are independent injection chambers that can inject different types of liquids. This embodiment demonstrates a variable-focus acoustic lens with 6 rings, an 80mm diameter, and a frequency of 500kHz. The radii of the odd-numbered rings (1, 3, and 5) are 14.5mm, 26mm, and 35.2mm, respectively, with a height of 3mm. They are made of PMMA, with a sound velocity of 2200m / s and a density of 1180kg / m³. Rings 2, 4, and 6 are hollow rings that can be injected with different liquids. The lens is sealed with an additional layer of sound-transmitting film on both the upper and lower layers. The radii of the hollow rings from the inside out are 14.7mm, 30.8mm, and 40mm, respectively, with a height of 3mm. The specific workflow of the system is as follows: B-mode ultrasound acquires images to locate the target area, obtaining the spatial coordinates of the stone's location, which are then converted to the lens coordinate system as (0, 0, 82). At this time, the liquid in the original independent injection chamber ring of the lens is water. The algorithm predicts that the current focal point of the lens is (0, 0, 79), with a difference of 4mm in the Z direction. The sound path difference is transmitted to the liquid density and sound velocity module. The calculated output density is 856.5kg / m3 and the sound velocity is 1325m / s. Based on the embedded liquid library, the density and sound velocity of the transformer oil are close to the output values. At this time, the microfluidic control device is activated to inject transformer oil into each ring. After injection, the ultrasonic driver is activated, and the sound field is focused at the measured target location. The simulation yields the sound pressure distribution of the two injected liquids as follows: Figure 3 As shown, the focal point is at 78.57 mm when the fluid in the annular ring is water, and at 82.12 mm when the fluid in the annular ring is transformer oil, which is in line with expectations and verifies the effectiveness of the system.

Claims

1. A smart acoustic lens focusing system suitable for crushing and discharging stones, characterized in that, include: The ultrasound module is used to acquire ultrasound images of the target stone in real time and determine the spatial coordinates of the stone. The improved Fresnel acoustic lens consists of multiple concentric rings, where the odd-numbered rings are fixed material rings and the even-numbered rings are cavities that can be independently injected with liquid; The microfluidic control module is used to inject liquids with different sound velocities into the injectable cavity according to control commands, so as to dynamically adjust the focusing characteristics of the acoustic lens; The control and calculation module is used to process ultrasound data, predict the current focal position, calculate the deviation between the target and the focal point, and generate liquid sound velocity adjustment commands.

2. The intelligent acoustic lens focusing system according to claim 1, characterized in that, The fixing material ring is made of PMMA, which has a sound velocity of 2200 m / s and a density of 1180 kg / m³. 3 ; The injectable liquid includes water, transformer oil, or a mixture thereof, and the liquid sound velocity is adjustable from 1325 m / s to 1500 m / s. The acoustic lens operates in a frequency range of 500kHz-1MHz and has a dynamic focal length adjustment range of 45mm-80mm.

3. The intelligent acoustic lens focusing system according to claim 1, characterized in that, The upper and lower surfaces of the acoustic lens are covered with a sound-transmitting film to seal the liquid cavity and ensure efficient transmission of sound waves.

4. The intelligent acoustic lens focusing system according to claim 1, characterized in that, The control calculation module includes a pre-trained finite element simulation model for predicting the focal position under different liquid configurations.

5. The intelligent acoustic lens focusing system according to claim 1, characterized in that, The microfluidic control module includes a liquid storage unit, a proportioning unit, and an injection unit, and can precisely adjust the sound velocity of the liquid in each annulus according to instructions.

6. A smart acoustic lens focusing method suitable for stone removal and crushing, characterized in that, Includes the following steps: S1. Target localization: The spatial coordinates of the stone are extracted by real-time acquisition of ultrasound images of the stone via B-ultrasound. S2, Focus Prediction: Calculate the current focus position based on the current liquid sound velocity in each annulus of the acoustic lens; S3. Deviation Calculation: Compare the target stone location with the predicted focal location and calculate the deviation vector; S4. Sound path difference calculation: Calculate the required sound path difference and phase compensation for each annulus based on the deviation. S5, Liquid sound velocity regulation: Inversely calculates the required liquid sound velocity for each annulus and controls the microfluidic module to inject the corresponding liquid; S6. Focus Verification: Re-predict the focus position and confirm whether it matches the target position. If it does not match, iterate and adjust.

7. The intelligent acoustic lens focusing method according to claim 6, characterized in that, In step S2, the focus prediction uses a pre-trained COMSOL finite element model, and the input parameters include the ring geometry, the liquid sound velocity, and the operating frequency.

8. The intelligent acoustic lens focusing method according to claim 6, characterized in that, In step S4, the formula for calculating the phase compensation amount is: Where f is the operating frequency, ΔL is the sound path difference, and c0 is the sound velocity of the background medium (water).

9. The intelligent acoustic lens focusing method according to claim 6, characterized in that, In step S5, the liquid sound velocity adjustment is based on a lookup table or real-time calculation, matching a preset liquid sound velocity-density database.

10. The intelligent acoustic lens focusing method according to claim 6, characterized in that, The method is applicable to extracorporeal shock wave lithotripsy and supports real-time dynamic adjustment to adapt to stone displacement or tissue deformation.

Images