CN117030083B - A shock wave therapy instrument impact strength testing system - Google Patents

Abstract

The invention discloses a shock wave therapeutic instrument impact strength test system, which relates to the field of shock wave mechanical parameter measurement, and comprises: the device comprises a soft tissue elastography body model, scattering objects uniformly distributed in the soft tissue elastography body model, an ultrasonic probe arranged on the surface of the soft tissue elastography body model, an ultrasonic imaging module connected with the ultrasonic probe, an ultrasonic image processing module connected with the ultrasonic imaging module and a shock wave mechanical parameter calculation module connected with the ultrasonic image processing module; the ultrasonic probe is arranged on the surface of the soft tissue elastography phantom in a direction perpendicular to the incidence direction of the target shock wave; the target shock wave is the shock wave emitted by the shock wave therapeutic instrument; according to the invention, by utilizing an ultrasonic imaging technology and measuring and calculating the displacement characteristics of the scatterer, the calculation of the mechanical parameters of the shock wave in the internal propagation process of the soft tissue elastography phantom is realized, and the quantitative description of the propagation process of the shock wave in the soft tissue elastography phantom is realized.

Description

A shock wave therapy instrument impact strength testing system

Technical field

The invention relates to the field of shock wave mechanical parameter measurement, and in particular to a shock wave therapy instrument impact strength testing system.

Background technique

Medical shock waves can induce a variety of biological effects in tissues through mechanical impact, and are widely used in the clinical treatment of musculoskeletal diseases. The key to shock wave therapy is to apply appropriate energy to the exact site. The energy used and the site selected directly determine the therapeutic effect. If the energy is too low, the therapeutic effect will not be achieved, while if the energy is too high, adverse reactions will occur. Therefore, it is of great significance to accurately describe the propagation rules of the shock wave stress field in different tissues, quantitatively obtain the mechanical load mode and energy magnitude of the tissue at the treatment target site, and evaluate the energy density level and damage risk along the transmission path.

Existing measurements of mechanical parameters of shock waves mostly use load cells to obtain the residual pressure after the shock wave penetrates the simulated load, and calculate the residual impact strength of the shock wave, or further calculate based on the residual pressure and the contact area between the shock wave treatment head and the load. energy density method. This method is a contact measurement. Due to the existence of the sensor, it will inevitably cause interference to the mechanical characteristics of the load and cannot obtain actual mechanical parameters. In addition, the propagation characteristics of shock waves in soft tissues are similar to sound waves, and the measurement results at the peak or trough positions vary greatly. Therefore, a limited number of sensors cannot reconstruct the complete force field distribution and propagation rules of shock waves within soft tissues, and thus cannot accurately evaluate the tissue. Internally loaded energy level.

Contents of the invention

The purpose of the present invention is to provide an impact strength testing system for a shock wave therapy device to solve the above problems.

In order to achieve the above objects, the present invention provides the following solutions.

A shock wave therapy instrument impact strength testing system, including: a soft tissue elastic imaging phantom, scatterers evenly distributed inside the soft tissue elastic imaging phantom, an ultrasonic probe arranged on the surface of the soft tissue elastic imaging phantom, and the The ultrasonic imaging module connected to the ultrasonic probe, the ultrasonic image processing module connected to the ultrasonic imaging module, and the shock wave mechanical parameter calculation module connected to the ultrasonic image processing module.

Wherein, the direction in which the ultrasonic probe is arranged on the surface of the soft tissue elastic imaging phantom is perpendicular to the incident direction of the target shock wave; the target shock wave is a shock wave emitted by a shock wave therapy instrument.

The ultrasonic probe is used to generate ultrasonic excitation and act on the soft tissue elastic imaging phantom and obtain ultrasonic echo signals during the impact process of the shock wave therapy device.

The ultrasonic imaging module is configured to receive the ultrasonic echo signal acquired by the ultrasonic probe and generate a continuous ultrasonic image sequence according to the intensity value of the ultrasonic echo signal.

The ultrasound image processing module is used to preprocess the ultrasound image sequence to obtain a sequence of slice sonograms, and perform a cross-correlation operation on two adjacent slice sonograms in the sequence of slice sonograms, Obtain the curve of the image cross-correlation coefficient changing with time.

The shock wave mechanical parameter calculation module is used to calculate and determine the shock wave mechanical parameters at different positions inside the soft tissue elastography phantom based on the time-varying curve of the image cross-correlation coefficient and the parameters of the soft tissue elastography phantom.

Through the reflectors evenly distributed inside the soft tissue elastography phantom, the force field distribution of the shock wave inside the soft tissue elastography phantom can be comprehensively detected, and the shock wave propagation process within the soft tissue elastography phantom can be quantitatively described, which can be more accurate. Evaluation of mechanical effects.

Description of the drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the drawings needed to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some of the drawings of the present invention. Embodiments, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without exerting creative efforts.

Figure 1 is a partial structural schematic diagram of an impact strength testing system for a shock wave therapy device provided by an embodiment of the present invention.

Figure 2 is a structural block diagram of an impact strength testing system for a shock wave therapy device provided by an embodiment of the present invention.

Figure 3 is a schematic diagram of propagation time calculation provided by an embodiment of the present invention.

Figure 4 is a schematic diagram of the calculation principle of shock wave mechanical parameters provided by the embodiment of the present invention.

Figure 5 is a work flow chart of an impact strength testing system for a shock wave therapy device provided by an embodiment of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

In order to make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

As shown in Figures 1 and 2, this embodiment provides a shock wave therapy instrument impact strength testing system including: a soft tissue elastography phantom 2, scatterers evenly distributed inside the soft tissue elastography phantom 2, and a The ultrasonic probe 3 on the surface of the soft tissue elastic imaging phantom 2, the ultrasonic imaging module connected to the ultrasonic probe 3, the ultrasonic image processing module connected to the ultrasonic imaging module, and the shock wave connected to the ultrasonic image processing module Mechanical parameter calculation module.

The scatterers are used for ultrasonic visualization of deformations in soft tissue elastography phantoms.

The ultrasonic probe 3 is arranged on the surface of the soft tissue elastic imaging phantom in a direction perpendicular to the incident direction of the target shock wave; the target shock wave is the shock wave emitted by the shock wave therapy device 1; the ultrasonic probe 3 is used to generate ultrasonic excitation And it acts on the soft tissue elastic imaging phantom and acquires the ultrasonic echo signal during the impact of the shock wave therapy device.

The ultrasonic imaging module is configured to receive the ultrasonic echo signal acquired by the ultrasonic probe, and generate a continuous ultrasonic image sequence (ie, a two-dimensional image sequence) according to the intensity value of the ultrasonic echo signal; wherein, in the ultrasonic image sequence Medium, when the imaging depth is 10cm and the lateral resolution at 5cm is greater than 2mm, the frame rate is greater than 30 frames. In addition, the soft tissue elastography phantom and scatterers are displayed as pixels with different brightness in the ultrasound image; in addition, the ultrasound imaging module is also used to excite the ultrasound probe to generate ultrasound excitation.

The ultrasound image processing module is used to preprocess the ultrasound image sequence to obtain a sequence of slice sonograms, and perform a cross-correlation operation on two adjacent slice sonograms in the sequence of slice sonograms, Obtain the curve of the image cross-correlation coefficient changing with time.

The shock wave mechanical parameter calculation module is used to calculate and determine the shock wave mechanical parameters at different positions inside the soft tissue elastography phantom based on the time-varying curve of the image cross-correlation coefficient and the parameters of the soft tissue elastography phantom.

In this embodiment, the soft tissue elastography phantom 2 is a cubic hydrogel phantom with a constant elastic modulus. That is, the soft tissue elastography phantom 2 is made of hydrogel and purified water mixed in a certain proportion, and has a constant elastic modulus. The elastic modulus is similar to that of muscle or fat tissue (elastic modulus is about 2 kPa). The scatterers are solid particles with a particle size of about 100 microns. The acoustic impedance characteristics of the scatterers are similar to those of the soft tissue elastography phantom 2. There are significant differences in acoustic impedance characteristics.

Further, the soft tissue elastography phantom 2 is produced using the following steps: (1) Take an appropriate amount of hydrogel dry powder and dissolve it in purified water according to a predetermined proportion, heat and boil until completely dissolved, and stir evenly to form a mixed solution; (2) Take an appropriate amount of Scatter sub-particles, add them to the mixed solution, and stir evenly; (3) After the phantom is completely solidified, cut it into blocks of predetermined size to obtain a soft tissue elastography phantom for ultrasound imaging.

Further, the density of the soft tissue elastography phantom 2 The determination process is: first weigh the weight W of a soft tissue elastography phantom in the air, then measure the length a, width b, and height c of the soft tissue elastography phantom, and finally according to the formula Calculate the density of soft tissue elastography phantoms.

In this embodiment, the emission direction of the shock wave emitted by the treatment head of the shock wave therapy instrument 1 is perpendicular to the incident surface and perpendicular to the ultrasonic excitation direction emitted by the ultrasonic probe 3 .

In this embodiment, in terms of preprocessing the ultrasonic image sequence to obtain a slice sonogram sequence, the ultrasonic image processing module is used to: obtain the ultrasonic image sequence, and process the ultrasonic image sequence in the ultrasonic image sequence. The ultrasound image is subjected to linear interpolation and image enhancement processing to obtain a sequence of slice sonograms of the target shock wave propagation process within the soft tissue elastography phantom.

Among them, linear interpolation is specifically to obtain continuous deformation signals, interpolating images from 30 frames per second to 100 frames per second, which is beneficial to the accuracy of image cross-correlation coefficient calculation. Image enhancement includes linear histogram stretching and contrast enhancement, which are used to improve the brightness information of feature points.

In this embodiment, in the sequence of slice sonograms, the corrcoef function in the numpy package is used, and the environment is python3. The cross-correlation operation is performed on two adjacent slice sonograms, and the image cross-correlation coefficient x changes with time. The curve x(t) of The larger the value of . Formula in/> is the elastic deformation amount of the soft tissue elastography phantom, k is the proportion coefficient to be determined, and x is the image cross-correlation coefficient.

The proportional coefficient k can be calibrated by performing a compression experiment on a soft tissue elastography phantom using a material testing machine. The specific operation method is: a. Under no stress, perform ultrasonic elastography on the soft tissue elastography phantom to obtain the initial state sonogram A; b. Compress the soft tissue elastography phantom to the maximum elastic deformation amount. , obtain the sonogram B at this time through the ultrasound imaging module; c. Perform cross-correlation operations on the sonogram A and the sonogram B to obtain the correlation coefficient x; and according to the formula Get the proportional coefficient k.

In this embodiment, the shock wave mechanical parameters include impact force, propagation speed and shock wave energy flow density, and the calculation process is shown in Figure 4.

Further, in terms of calculating impact force, the shock wave mechanical parameter calculation module is used: according to the formula Calculate impact force.

Among them, F(t) is the impact force curve that changes with time, E is the elastic modulus of the soft tissue elastography phantom, measured by a compression experiment using a material testing machine; x(t) is the image cross-correlation coefficient x that changes with time The curve of is also used to characterize the deformation variable of the soft tissue elastography phantom; L is the size of the soft tissue elastography phantom, which is 10 cm in one embodiment; S is the action area of the energy.

Further, in terms of calculating the propagation speed, the shock wave mechanical parameter calculation module is used: according to the formula Calculate the speed of propagation.

x(t) is the curve of the image correlation coefficient x changing with time, and it is also the curve of the soft tissue elastography phantom deformation variable changing with time. According to x(t), we can get the time t1 when the shock wave starts to be loaded onto the soft tissue elastography phantom. , the time t2 when the deformation of the soft tissue elastography phantom reaches the maximum, That is the propagation time of the shock wave in the soft tissue elastography phantom. Combined with the length d of the soft tissue elastography phantom, the propagation speed of the shock wave in the soft tissue elastography phantom can be obtained/> , the details are shown in Figure 3.

In terms of calculating shock wave energy density, the shock wave mechanical parameter calculation module is used: according to the formula Calculate shock wave energy density.

in, is the shock wave energy flux density, and P is the energy loaded during an impact. This energy represents the effective therapeutic energy that the shock wave generated by the shock wave therapy device passes through the biological tissue, that is, the soft tissue elastography phantom is attenuated and then transferred to the deep affected area. It is the best way to evaluate shock wave therapy. An indicator of the energy penetration performance of the instrument, S is the area of action of energy P, F(t) is the pressure value that changes with time, that is, the calculated impact force,/> is the density of the soft tissue elastography phantom, c is the propagation speed of waves in the medium,/> That is the acoustic impedance of the medium.

This embodiment also provides a work flow of a shock wave therapy instrument impact strength testing system, as shown in Figure 5, which specifically includes the following steps.

First, start the shock wave therapy device.

Second, the soft tissue elastography phantom is used to receive the shock wave emitted by the treatment head of the shock wave therapy device, so that the shock wave enters the interior of the soft tissue elastography phantom from the incident surface and causes internal deformation of the soft tissue elastography phantom. This deformation causes the embedded ultrasound The relative position of the scatterers changes.

Third, use an ultrasonic probe to emit and obtain ultrasonic reflection signals.

Fourth, the ultrasound imaging module obtains an ultrasound image sequence based on the ultrasound reflection signal.

Fifth, the ultrasound image processing module enhances the ultrasound image, performs linear interpolation on the ultrasound image according to a fixed time interval Δt, and performs cross-correlation operations on the two adjacent images to obtain the displacement over time. Signal x(t).

Sixth, the shock wave intensity calculation module calculates the impact force, shock wave propagation speed, and shock wave energy flow density parameters based on the obtained displacement signal.

The invention can achieve quantitative description of the propagation process of shock waves in soft tissue elastic imaging phantoms and be used for accurate evaluation of the performance of shock wave therapy instruments.

Each embodiment in this specification is described in a progressive manner. Each embodiment focuses on its differences from other embodiments. The same and similar parts between the various embodiments can be referred to each other.

This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and the core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the present invention There will be changes in the specific implementation methods and application scope of the ideas. In summary, the contents of this description should not be construed as limitations of the present invention.

Claims (7)

1. A shock wave therapy instrument impact strength testing system, characterized in that it includes: a soft tissue elastic imaging phantom, scatterers evenly distributed inside the soft tissue elastic imaging phantom, and arranged on the surface of the soft tissue elastic imaging phantom. An ultrasonic probe, an ultrasonic imaging module connected to the ultrasonic probe, an ultrasonic image processing module connected to the ultrasonic imaging module, and a shock wave mechanical parameter calculation module connected to the ultrasonic image processing module; Wherein, the direction in which the ultrasonic probe is arranged on the surface of the soft tissue elastic imaging phantom is perpendicular to the incident direction of the target shock wave; the target shock wave is a shock wave emitted by a shock wave therapy instrument; The ultrasonic probe is used to generate ultrasonic excitation and act on the soft tissue elastic imaging phantom and obtain ultrasonic echo signals during the impact of the shock wave therapy device; The ultrasonic imaging module is configured to receive the ultrasonic echo signal acquired by the ultrasonic probe and generate a continuous ultrasonic image sequence according to the intensity value of the ultrasonic echo signal; The ultrasound image processing module is used to preprocess the ultrasound image sequence to obtain a sequence of slice sonograms, and perform a cross-correlation operation on two adjacent slice sonograms in the sequence of slice sonograms, Obtain the curve of the image cross-correlation coefficient changing with time; The shock wave mechanical parameter calculation module is used to calculate and determine the shock wave mechanical parameters at different positions inside the soft tissue elastography phantom based on the curve of the image cross-correlation coefficient changing with time and the parameters of the soft tissue elastography phantom; The shock wave mechanical parameters include impact force, propagation speed and shock wave energy flow density. 2. A shock wave therapy instrument impact strength testing system according to claim 1, characterized in that the soft tissue elastic imaging phantom is a cubic hydrogel phantom with constant elastic modulus. 3. A shock wave therapy instrument impact strength testing system according to claim 1, characterized in that the acoustic impedance characteristics of the scatterers are different from the acoustic impedance characteristics of the soft tissue elastography phantom. 4. A shock wave therapy instrument impact strength testing system according to claim 1, wherein the ultrasonic image processing module is used to preprocess the ultrasonic image sequence to obtain a slice sonogram sequence. : The ultrasound image sequence is acquired, and the ultrasound images in the ultrasound image sequence are linearly interpolated and image enhanced to obtain a sequence of slice sonograms of the target shock wave propagation process inside the soft tissue elastic imaging phantom. 5. A shock wave therapy instrument impact strength testing system according to claim 1, characterized in that, in terms of calculating impact force, the shock wave mechanical parameter calculation module is used for: According to the formula Calculate impact force; Among them, F(t) is the impact force curve changing with time, E is the elastic modulus of the soft tissue elastography phantom, x(t) is the curve of the image cross-correlation coefficient x changing with time, k is the proportion coefficient, and L is The size of the soft tissue elastography phantom, S is the area of action of the energy. 6. A shock wave therapy instrument impact strength testing system according to claim 1, characterized in that, in terms of calculating propagation speed, the shock wave mechanical parameter calculation module is used for: According to the formula Calculate propagation speed; Among them, c is the propagation speed of the shock wave in the soft tissue elastography phantom, d is the length of the soft tissue elastography phantom, is the propagation time of the shock wave in the soft tissue elastography phantom,/> , t1 is the time when the shock wave starts to be loaded onto the soft tissue elastography phantom, and t2 is the time when the deformation of the soft tissue elastography phantom reaches the maximum. 7. A shock wave therapy instrument impact strength testing system according to claim 5, characterized in that, in terms of calculating shock wave energy density, the shock wave mechanical parameter calculation module is used for: According to the formula Calculate shock wave energy density; in, is the shock wave energy flow density, P is the energy loaded during an impact,/> is the density of the soft tissue elastography phantom, and c is the propagation speed of waves in the medium.