CN105572049B - Optoacoustic quantifies elastograph imaging method and device - Google Patents

Abstract

The invention discloses a method and device for photoacoustic quantitative elastography. The method comprises: a laser emits pulsed laser light, the pulsed laser light is focused through a focusing lens, and shines on a tissue sample to excite a photoacoustic signal, and the photoacoustic signal passes through a coupling groove The coupling liquid is received by the ultrasonic detector; the photoacoustic signal received by the ultrasonic detector is amplified by the amplifier, collected by the oscilloscope, and the signal information is stored in the computer. The computer controls the stepping motor to move the tissue sample point by point, and the corresponding tissue sample Form an X-Y two-dimensional plane scanning area; after the oscilloscope collects all the signals, the computer calculates the quantitative elastic modulus of the tissue sample at each point; according to the calculated quantitative elastic modulus, the quantitative elastic two-dimensional image of the tissue sample is reconstructed; The device includes a photoacoustic excitation source, a signal acquisition/transmission/reconstruction component, a coupling slot, a stepper motor and an X-Y two-dimensional scanning platform. The invention can realize non-destructive, high-resolution quantitative measurement and imaging of tissue elasticity.

Description

Photoacoustic quantitative elastography method and device

technical field

The invention relates to an elastography method and device, in particular to a photoacoustic quantitative elastography method and device, belonging to the technical field of biomedical detection.

Background technique

The pathological changes of tissues are often accompanied by the changes of their mechanical properties, especially the elastic modulus, so the detection of tissue lesions can be realized by analyzing the physical parameters of tissues. At present, the method of predicting tissue diseases by detecting tissue elasticity has been widely accepted by doctors and imaging researchers. For example, the detection method of non-destructive liver cirrhosis using ultrasound elasticity detection method has been applied to the parameter detection of clinical diseases.

The existing quantitative elastic testing methods are mainly static ultrasonic elastic testing and ultrasonic shear wave elastography. The static ultrasonic elastic detection method adopts a static or quasi-static tissue excitation method, artificially uses a known force to squeeze the tissue to cause deformation of the tissue, and uses ultrasonic imaging to obtain the displacement in the tissue. According to the elastic modulus equal to (force/displacement ), the quantitative elastic modulus can be obtained. The disadvantage of this approach is that modeling the tissue as a pure elastic body, ignoring the fact that the tissue has viscoelastic properties, inevitably leads to inaccurate measurements. At the same time, the distribution of the force exerted on the tissue in this method is affected by the shape of the tissue sample and the excitation means, resulting in a large deviation between the measurement result and the true value. Ultrasonic shear wave elastography uses the nonlinear effect induced by focused ultrasound at the focal point to excite shear waves, and obtains the elastic modulus of tissues by measuring the propagation velocity of shear waves in tissues. This method is mainly used in the elastic detection of large tissues and organs such as breast and thyroid gland. It has the disadvantages of low excitation efficiency and inaccurate detection of small lesions, and the high energy of the focused area will cause damage to biological tissues or detection areas due to temperature rise. Changes in physiological properties are inevitable. at the same time. The current quantitative elasticity detection and imaging can mainly be realized in large organs, and the elasticity imaging of vascular diseases still stays at the level of imaging strain maps and cannot achieve quantitative elasticity imaging. The photoacoustic quantitative measurement and imaging method of tissue elastic modulus proposed in this paper can realize quantitative elastic measurement and imaging of small lesions without damage, and has incomparable advantages compared with existing elastic measurement and imaging techniques.

At present, the use of photoacoustic method to detect tissue elasticity has been reported in my country, such as the invention patent published on September 7, 2011: photoacoustic elastography method and device, applicant: South China Normal University, application date: January 14, 2011 Japan, application number: 201110008213.5, which uses an intensity-modulated continuous light source to excite a photoacoustic signal. By measuring the phase difference between the signal and the modulated signal and scanning point by point, the elastic distribution image of the tissue sample can be reconstructed. However, in the above method, the quantitative measurement of the tissue elastic modulus cannot be realized, that is, the absolute value of the elastic modulus cannot be obtained, and only relative values can be provided, which reduces the accuracy of the measurement results of this method in practical applications.

Contents of the invention

The object of the present invention is to solve the above-mentioned defects in the prior art, and provide a photoacoustic quantitative elastography method, which can realize non-destructive, high-resolution quantitative measurement and imaging of tissue elasticity.

Another object of the present invention is to provide a photoacoustic quantitative elastography device for realizing the above method.

The purpose of the present invention can be achieved by taking the following technical solutions:

A photoacoustic quantitative elastography method, the method comprising the steps of:

1) Place the tissue sample on the X-Y two-dimensional scanning platform and immerse it in the coupling liquid of the coupling tank; set the focusing lens directly above the tissue sample, and adjust the height of the focusing lens so that the focus of the focusing lens does not deviate from the surface of the tissue sample ;Aim the ultrasonic probe at the tissue sample, and make the lower end of the ultrasonic probe enter the coupling liquid in the coupling tank;

2) The laser emits pulsed laser light, which is focused by the focusing lens and irradiated on the tissue sample to excite a photoacoustic signal, which is received by the ultrasonic detector after passing through the coupling liquid in the coupling tank;

3) The photoacoustic signal received by the ultrasonic detector is amplified by the amplifier and collected by the oscilloscope. The oscilloscope stores the collected signal information in the computer. The computer controls the stepping motor to move the tissue sample point by point, and forms an X-Y two-dimensional image on the corresponding tissue sample. In the plane scanning area, every time the stepper motor moves, the oscilloscope performs a signal acquisition;

4) After the oscilloscope has collected all the signals, the computer integrates the signals at each point with respect to time to obtain the time function of the vibration displacement of the tissue sample surface; obtain the time required for the surface vibration displacement of the tissue sample to rise from zero to its maximum value, and use At this time, the quantitative elastic modulus of the tissue sample at each point is calculated; according to the calculated quantitative elastic modulus, the quantitative elastic two-dimensional image of the tissue sample is reconstructed.

As a preferred solution, in step 1), the step of allowing the lower end of the ultrasonic probe to enter the coupling liquid in the coupling tank specifically includes: allowing the lower end of the ultrasonic probe to enter the coupling liquid in the coupling tank at a depth of 5-8mm.

As a preferred solution, in step 3), the computer controls the stepping motor to move the tissue sample point by point refers to: the computer uses the Labview program to control the stepping motor to move the tissue sample point by point; in step 4), the computer moves each Integrating the signal of each point with respect to time means that the computer uses the Matlab program to integrate the signal of each point with respect to time once.

As a preferred solution, in step 4), the quantitative elastic modulus of the tissue sample at each point of the calculation adopts the following formula:

Among them, ρ is the density of biological tissue, R is the radius of the laser spot, and t _max is the time required for the surface vibration displacement of the tissue sample to rise from zero to its maximum value.

Another object of the present invention can be achieved by taking the following technical solutions:

A photoacoustic quantitative elastography device, the device includes a photoacoustic excitation source, a signal acquisition/transmission/reconstruction component, a coupling groove, a stepper motor and an X-Y two-dimensional scanning platform, and the photoacoustic excitation source includes a laser and a focusing lens; The signal acquisition/transmission/reconstruction assembly includes an ultrasonic detector, an amplifier, an oscilloscope and a computer, the ultrasonic detector, the amplifier, an oscilloscope and the computer are connected in sequence, and the computer is equipped with an acquisition control and signal processing system; the stepping motor Connected to a computer, the X-Y two-dimensional scanning platform is placed in a coupling tank, and the coupling tank is filled with coupling liquid;

During the test, the tissue sample is placed on the X-Y two-dimensional scanning platform and immersed in the coupling liquid in the coupling tank; the focusing lens is set directly above the tissue sample, and the focus of the focusing lens does not deviate from the surface of the tissue sample, and the laser emits The pulsed laser light is focused through the focusing lens and irradiated on the tissue sample; the ultrasonic probe is aimed at the tissue sample, and the lower end of the ultrasonic probe enters the coupling liquid in the coupling groove to receive the photoacoustic signal excited by the tissue sample; The computer controls the stepper motor to move the tissue sample point by point.

As a preferred solution, the device further includes an instrument fixing/supporting instrument assembly, and the instrument fixing/supporting instrument assembly is used for fixing/supporting the X-Y two-dimensional scanning platform, the focusing lens and the ultrasonic probe.

As a preferred solution, the ultrasonic detector is a hydrophone with a response frequency of 200KHz-15MHz and a diameter of 1 mm; the piezoelectric conversion part of the ultrasonic detector is a gold electrode polyvinylidene fluoride film with a thickness of 28 μm , when receiving a photoacoustic signal, the polyvinylidene fluoride membrane of the gold electrode is aligned with the tissue sample.

As a preferred solution, the sampling rate of the oscilloscope is 2.5GHz, and the acquisition control and signal processing system installed in the computer is programmed by using Labview and Matlab programs.

As a preferred solution, the wavelength of the pulse laser emitted by the laser is 400-2500 nm, the pulse width is 1-50 ns, and the repetition frequency is 1 Hz-5 KHz.

As a preferred solution, the coupling liquid in the coupling tank is water, and the water temperature is monitored to keep the water temperature consistent with the temperature of the tissue sample.

Compared with the prior art, the present invention has the following beneficial effects:

1. In the present invention, the signal collected by the oscilloscope is integrated once over time to obtain the time function of the surface vibration displacement of the tissue sample, and the time required for the surface vibration displacement of the tissue sample to rise from zero to its maximum value is obtained, and the quantitative elasticity of the tissue is calculated using this time Modulus, compared with existing relative elastic measurement methods, does not require normal tissue as a reference and has higher accuracy.

2. The present invention uses a laser to emit pulsed laser light. The pulsed laser light is focused by a focusing lens and irradiated on a tissue sample to excite a photoacoustic signal, thereby performing tissue elasticity detection. Compared with the traditional ultrasonic elasticity detection method, it has tissue specificity. and high resolution capabilities.

3. The ultrasonic detector used in the present invention is a hydrophone with a response frequency of 200KHz-15MHz and a diameter of 1mm. It has the advantages of high detection sensitivity and no bandwidth limitation, thereby ensuring the ability of highly sensitive detection.

4. The photoacoustic quantitative elastic detection method of the present invention has the ability of rapid detection, and the device for realizing the method is simple in structure and easy to use, and can be widely used in tissue elastic imaging, which is convenient for industrialization.

Description of drawings

FIG. 1 is a schematic structural diagram of a photoacoustic quantitative elastography device according to Embodiment 1 of the present invention.

FIG. 2 is a graph showing the dependence of displacement on time in Example 1 of the present invention.

Fig. 3 is a schematic diagram of agar sample a of Example 2 of the present invention.

Fig. 4 is a schematic diagram of agar sample b of Example 2 of the present invention.

Fig. 5 is a photoacoustic image of agar sample a in Example 2 of the present invention.

Fig. 6 is a photoacoustic image of agar sample b in Example 2 of the present invention.

Fig. 7 is a photoacoustic elastic image of agar sample a in Example 2 of the present invention.

Fig. 8 is a photoacoustic elastic image of agar sample b in Example 2 of the present invention.

FIG. 9 is a curve diagram of elastic modulus at the dotted line in FIG. 3 and FIG. 4 .

Among them, 1-coupling tank, 2-stepping motor, 3-laser, 4-focusing lens, 5-ultrasonic detector, 6-amplifier, 7-oscilloscope, 8-computer, 9-tissue sample.

Detailed ways

The present invention will be further described in detail below in conjunction with the embodiments and the accompanying drawings, but the embodiments of the present invention are not limited thereto.

Example 1:

As shown in Figure 1, the photoacoustic quantitative elastography device of this embodiment includes a photoacoustic excitation source, a signal acquisition/transmission/reconstruction component, a coupling tank 1, a stepping motor 2, an X-Y two-dimensional scanning platform and an instrument fixing/supporting device Components (not shown in the figure), the photoacoustic excitation source includes a laser 3 and a focusing lens 4; the signal acquisition/transmission/reconstruction assembly includes an ultrasonic probe 5, an amplifier 6, an oscilloscope 7 and a computer 8, and the ultrasonic Detector 5, amplifier 6, oscilloscope 7 and computer 8 are connected successively; The sampling rate of described oscilloscope 7 is 2.5GHz; Described computer 8 is equipped with acquisition control and signal processing system, and this system utilizes Labview and Matlab program to form; The stepper motor 2 is connected to the computer 8, the X-Y two-dimensional scanning platform is placed in the coupling tank 1, and the coupling tank 1 is filled with coupling liquid;

The ultrasonic probe 5 is a hydrophone with a response frequency of 200 KHz-15 MHz and a diameter of 1 mm; the piezoelectric conversion part of the ultrasonic probe is a gold electrode polyvinylidene fluoride film with a thickness of 28 μm.

The instrument fixing/supporting instrument assembly is used to fix/support the X-Y two-dimensional scanning platform, the focusing lens 4 and the ultrasonic probe 5 .

To realize the photoacoustic quantitative elastography method of this embodiment, the following principles are mainly adopted:

The tissue is irradiated by laser to generate shear wave, whose equation is:

Among them, u _z is the displacement in the z direction, that is, the direction of the excitation light, which is the shear wave displacement and also the displacement when the photoacoustic signal is generated after the tissue is excited. is the shear wave velocity, μ is the shear modulus, v=μ/ρ is the dynamic shear viscosity coefficient, and F _z is the photothermoelastic radiation force. At the laser focus position, M=β ₀ αI ₀ , β ₀ is the thermal expansion coefficient, α is the tissue absorption coefficient, and I ₀ is the laser intensity. r is the independent variable of the position, R is the radius of the laser spot, φ(t) is the relationship of the laser intensity with time, and the pulse width is t ₀ .

According to the solution of the ordinary differential equation, and carry out the Hankel transformation to get:

The above equation is written in the form of Green's function:

This shear displacement is simultaneously the displacement of the surface of the biological tissue when the photoacoustic signal is generated.

Because the relationship between the photoacoustic signal and the displacement satisfies:

Considering that the temperature change at the laser focus is a time-slow change, the variable is analyzed by the above formula:

The time elapsed for the amplitude of the photoacoustic signal to change from zero to its maximum value satisfies t _max =R/c _t , and the shear modulus μ satisfies μ=ρ(R/t _max ) ² ; where ρ is the density of biological tissue, which can be is 1100kg/m ³ , by using the relationship between elastic modulus and shear modulus E=2μ(1+η), where η is the Poisson’s ratio of biological tissue, which is taken as 0.499 due to the incompressibility of biological tissue, thereby obtaining the Quantitative modulus of elasticity:

Therefore, the photoacoustic quantitative elastography method of this embodiment includes the following steps:

1) The tissue sample 9 is placed on the X-Y two-dimensional scanning platform, and immersed in the coupling liquid of the coupling tank 1; the focusing lens 4 is arranged directly above the tissue sample 9, and the height of the focusing lens 4 is adjusted so that the focusing lens 4 The focus does not deviate from the surface of the tissue sample 9; the ultrasonic probe 5 is aligned with the tissue sample 9, that is, the polyvinylidene fluoride film of the gold electrode is aligned with the tissue sample 9, and the depth of the coupling liquid that makes the lower end of the ultrasonic probe 5 enter the coupling groove 1 is about In the 5-8mm position, the coupling liquid is water, and the water temperature is monitored to keep the water temperature consistent with the temperature of the tissue sample 9;

2) The laser 3 emits pulsed laser light with a wavelength of 400-2500 nm, a pulse width of 1-50 ns, and a repetition rate of 1 Hz-5 KHz. The pulsed laser light is focused by the focusing lens 4 and irradiated on the tissue sample 9 to excite light The acoustic signal, the photoacoustic signal is received by the ultrasonic detector 5 after passing through the coupling liquid in the coupling tank 1;

3) The photoacoustic signal received by the ultrasonic detector 5 is amplified by the amplifier 6 and collected by the oscilloscope 7. The oscilloscope 7 stores the collected signal information in the computer 8, and the computer 8 uses the Labview program to control the stepping motor 2 to move the tissue sample point by point 9. An X-Y two-dimensional plane scanning area is formed on the corresponding tissue sample 9, and each time the stepping motor 2 moves once, the oscilloscope 7 performs a signal acquisition;

4) After the oscilloscope 7 has collected all the signals, the computer 8 uses the Matlab program to integrate the signals of each point with respect to time to obtain the time function of the vibration displacement of the tissue sample surface; when the vibration displacement of the tissue sample surface rises from zero to its maximum value, The required time, as shown in Figure 2, provides four kinds of displacement relationships with time in the figure, different elastic modulus, the time required for displacement to reach the maximum value is not the same; through the above formula (6) , using the time to calculate the quantitative elastic modulus of the tissue sample at each point; according to the calculated quantitative elastic modulus, the quantitative elastic two-dimensional image of the tissue sample is reconstructed.

Example 2:

The present embodiment is the experiment that utilizes agar sample to carry out, mainly comprises the following steps:

1) Add 10% ink to make a square sample in the agar with a concentration of 20g/L, make agar with a concentration of 15g/L in the middle of it and add 3% ink to make a square sample, which forms a graph Agar sample a in 3; add 10% ink to agar with a concentration of 30g/L to make a square sample, make agar with a concentration of 25g/L in the middle of it and add 3% ink to make a square sample , which forms agar sample b in Figure 4;

2) start the laser, the output pulse laser has a wavelength of 532nm, a pulse width of 10ns, and a repetition rate of 15Hz; the pulse laser is irradiated on agar samples a and b after being focused by a focusing lens, and agar samples a and b are excited to emit photoacoustic signals, The photoacoustic signal is received by the ultrasonic detector after passing through the coupling liquid in the coupling tank;

3) After the photoacoustic signal received by the ultrasonic detector is amplified by the amplifier, it is transmitted to the oscilloscope for data collection, and the oscilloscope then transmits and stores the data to the computer, and the computer controls the stepping motor to form a corresponding scanning area on the sample;

4) After all the signals are collected, the collected data are first normalized, and then the photoacoustic image and the photoacoustic image are reconstructed by the maximum projection method and the elastic projection method. Figure 5 and Figure 6 are the photoacoustic images of agar samples a and b respectively. Acoustic image, it can be seen that the photoacoustic imaging of the displayed background agar has almost no contrast, and the photoacoustic imaging of the middle circular area has almost no contrast; Figure 7 and Figure 8 are the photoacoustic elastic images of agar samples a and b respectively, which can be It can be seen that the displayed photoacoustic elastography image shows a large contrast, which illustrates the necessity of photoacoustic elastography; a and b in Fig. 9 show the elasticity values of the agar samples at the dotted lines in Fig. 3 and Fig. 4 respectively, A clear change in the elasticity value can be seen.

In summary, the present invention proposes a new method for measuring the quantitative elastic modulus of tissue, compared with the existing method for measuring relative elasticity, it does not require normal tissue as a reference, and has higher accuracy; Tissue elasticity detection, compared with the traditional ultrasonic elasticity detection method, has tissue specificity and high resolution; the ultrasonic detector used is a hydrophone, which has the advantages of high detection sensitivity and no bandwidth limitation, thus ensuring high sensitivity detection Ability.

The above is only a preferred embodiment of the patent of the present invention, but the scope of protection of the patent of the present invention is not limited thereto. Equivalent replacements or changes to the technical solutions and their inventive concepts all fall within the scope of protection of the invention patent.

Claims (10)

1. optoacoustic quantifies elastograph imaging method, it is characterised in that：It the described method comprises the following steps：

1) tissue sample is placed in X-Y two-dimensional scanning platforms, and be immersed in the coupling liquid of coupling slot；Condenser lens is set The height set right over tissue sample, and adjust condenser lens makes the focus of condenser lens without departing from tissue sample surface；It will Ultrasonic detector is directed at tissue sample, and the lower end of ultrasonic detector is made to enter in the coupling liquid of coupling slot；

2) laser sends out pulse laser, which is focused by condenser lens, is impinged upon on tissue sample, and optoacoustic is inspired Signal, photoacoustic signal are received after the coupling liquid of coupling slot by ultrasonic detector；

3) photoacoustic signal that ultrasonic detector receives is acquired after amplifier amplifies by oscillograph, and oscillograph is by the signal of acquisition In information storage to computer, computer-controlled stepper motor moves tissue sample point by point, and X-Y is formed on corresponding tissue sample Two dimensional surface scanning area, stepper motor is often mobile primary, and oscillograph just carries out a signal acquisition；

4) after oscillograph has acquired whole signals, computer once integrates the signal of each point the time, obtains tissue sample The function of time of product surface vibration displacement；Obtain tissue sample surface vibration displacement from it is above freezing rise to its maximum value when taken Between, the tissue sample that each point is calculated using the time quantifies elasticity modulus；According to the quantitative elasticity modulus of calculating, tissue is reconstructed The quantitative elastic two dimensional image of sample.

2. optoacoustic according to claim 1 quantifies elastograph imaging method, it is characterised in that：It is described to make ultrasound in step 1) The lower end of detector enters in the coupling liquid of coupling slot：Keep the coupling liquid that the lower end of ultrasonic detector enters coupling slot deep It spends at 5-8mm.

3. optoacoustic according to claim 1 quantifies elastograph imaging method, it is characterised in that：In step 3), the computer Control stepper motor moves tissue sample and refers to point by point：Computer moves group point by point using Labview programs control stepper motor Tissue samples；In step 4), the signal of each point is carried out primary integral to the time and refers to by the computer：Computer utilizes Matlab Program once integrates the signal of each point the time.

4. optoacoustic according to claim 1 quantifies elastograph imaging method, it is characterised in that：It is described to calculate respectively in step 4) The tissue sample of point quantifies elasticity modulus, using following formula：

Wherein, ρ is biological tissue density, and R is laser facula radius, t_maxIt is risen to from above freezing for tissue sample surface vibration displacement The time required to when its maximum value.

5. optoacoustic quantifies elastogram device, it is characterised in that：Described device includes photo-acoustic excitation source, signal acquisition/transmission/weight Component, coupling slot, stepper motor and X-Y two-dimensional scanning platforms are built, the photo-acoustic excitation source includes laser and condenser lens；Institute It includes ultrasonic detector, amplifier, oscillograph and computer to state signal acquisition/transmission/reconstruction component, the ultrasonic detector, Amplifier, oscillograph and computer are sequentially connected, and the computer is equipped with acquisition control and signal processing system；The stepping Motor is connected with computer, and the X-Y two-dimensional scanning platforms are placed in coupling slot, and coupling liquid is full of in the coupling slot；

When test, tissue sample is placed in X-Y two-dimensional scanning platforms, and is immersed in the coupling liquid of coupling slot；The focusing Lens are arranged right over tissue sample, and the focus of condenser lens is without departing from tissue sample surface, what the laser was sent out Pulse laser is focused by condenser lens, is impinged upon on tissue sample；The ultrasonic detector is directed at tissue sample, and supersonic sounding The lower end of device enters in the coupling liquid of coupling slot, receives the photoacoustic signal that tissue sample is inspired；What ultrasonic detector received Photoacoustic signal is acquired after amplifier amplifies by oscillograph, and oscillograph is calculated in the signal message storage to computer of acquisition Machine control stepper motor moves tissue sample point by point, and X-Y two dimensional surface scanning areas, stepping electricity are formed on corresponding tissue sample Machine is often mobile primary, and oscillograph just carries out a signal acquisition；After oscillograph has acquired whole signals, computer is by the letter of each point Number the time is once integrated, obtains the function of time of tissue sample surface vibration displacement；Obtain tissue sample surface vibration Displacement from it is above freezing rise to its maximum value when the time required to, the tissue sample that each point is calculated using the time quantifies elasticity modulus；Root According to the quantitative elasticity modulus of calculating, the quantitative elastic two dimensional image of tissue sample is reconstructed.

6. optoacoustic according to claim 5 quantifies elastogram device, it is characterised in that：Described device further includes that instrument is solid Fixed/fixing device component, the instrument are fixed, and/fixing device component is for fixing/supports X-Y two-dimensional scanning platforms, focuses thoroughly Mirror and ultrasonic detector.

7. optoacoustic according to claim 5 or 6 quantifies elastogram device, it is characterised in that：The ultrasonic detector is Hydrophone, response frequency 200KHz-15MHz, a diameter of 1mm；The piezoelectricity converting member of ultrasonic detector is that a thickness is 28 μm of gold electrode PVDF membrane, when receiving photoacoustic signal, which is directed at tissue sample.

8. optoacoustic according to claim 5 or 6 quantifies elastogram device, it is characterised in that：The sampling of the oscillograph Rate is 2.5GHz, and the acquisition control and signal processing system of the computer installation utilize Labview and Matlab programmings It forms.

9. optoacoustic according to claim 5 or 6 quantifies elastogram device, it is characterised in that：What the laser was sent out Pulse laser wavelength is 400~2500nm, and pulse width is 1~50ns, and repetition rate is 1Hz~5KHz.

10. optoacoustic according to claim 5 or 6 quantifies elastogram device, it is characterised in that：Coupling in the coupling slot Conjunction liquid is water, monitors water temperature, the temperature of water temperature and tissue sample is made to be consistent.