CN104473638B - Mammary tissue elastography detection array structure based on piezoelectric impedance method and detection method of mammary tissue elastography detection array structure - Google Patents

Abstract

The invention discloses a mammary tissue elastography detection array structure based on a piezoelectric impedance method and a detection method of the mammary tissue elastography detection array structure. The detection array structure is characterized in that multiple piezoelectric unit structures are arranged on the internal surface of a supporting frame to form a shape similar to the surface of a breast, and can be worn on the to-be-detected breast of a human body; based on the piezoelectric impedance method, the analysis relationship between the resonance frequency of the piezoelectric unit structures and the elastic information of a to-be-detected sample is obtained by measuring the resonance frequency of piezoelectric parameters such as the admittances and the phases of the piezoelectric unit structures and according to an established corresponding piezoelectric equivalent circuit model. According to the detection method provided by the invention, the specificity is strong; a quantitative detection result can be given; therefore the structure and the method are more applicable for the detection of the breast cancer that a cancer tissue is located in the superficial zone, and the difficult problem that the detection on the superficial tissue is difficultly realized through ultrasonic elastography is solved; the structure and the method are simple and reliable; not only can assistance be provided for the implementation of physical examination by medical workers, but also the daily physical examination in a family can be realized, so the early discovery and the early treatment of related breast diseases can be favourably realized.

Description

Mammary gland elastography detection array structure based on piezoelectric impedance method and detection method thereof

Technical Field

The invention belongs to the field of medical health detection, and particularly relates to a mammary gland elastography detection array structure based on a piezoelectric impedance method and a detection method thereof.

Background

Mammary gland is one of the most important organs of human body, and the incidence rate of diseases related to mammary gland is always high, and the diseases have obvious influence on the normal production and life of residents, and enough attention needs to be paid. While breast cancer is a major concern of the malignant disease among these breast-related diseases, it is noted that, despite the current improvement in living levels and medical conditions, the incidence of breast cancer continues to increase and has a consistently high mortality rate.

The current approach to such malignant diseases is to find a policy for early treatment, but early diagnosis of breast cancer cancerous tissues remains challenging: daily palpation examination needs abundant clinical experience to find early-onset cancerous tissues, and the body self-examination of ordinary people without related experience is almost impossible to find; in addition, breast cancer tissues are not obvious in ultrasonic reflection echo due to low specificity. Therefore, the breast cancer is difficult to find by the conventional ultrasonic detection adopted in the physical examination.

How to solve the early detection and early diagnosis of breast related diseases, especially breast cancer, has become a problem which needs to be solved urgently in the medical field. It is noteworthy that there are studies showing that the elastic properties of human tissue, such as young's modulus, change significantly after a lesion. Based on the characteristics, at present, scholars at home and abroad put forward the concept of 'elastography', namely, an advanced imaging method is used for imaging the elastic properties of tissues, and the elastic modulus is used as a diagnosis index to judge whether human tissues are diseased or not and diagnose the degree of the diseases. Currently, the elastography technology which is widely applied comprises methods such as ultrasonic elastography UE, nuclear magnetic resonance elastography MRI and the like. However, the breast cancer cancerous tissue is located on a superficial layer, and the breast cancer tissue is difficult to accurately find by using the technologies such as ultrasonic elastography and the like due to the near-field effect, so that an elastography method suitable for breast cancer is urgently needed to be provided.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a breast elastography detection system based on a piezoelectric impedance method and a detection method thereof, which are suitable for health monitoring of a breast and can be used for early diagnosis and treatment of breast related diseases such as breast cancer.

The invention aims to provide a mammary gland elastography detection array structure based on a piezoelectric impedance method.

The mammary gland elasticity imaging detection array structure based on the piezoelectric impedance method comprises the following components: a plurality of piezoelectric unit structures and a support frame; each piezoelectric unit structure comprises a plurality of supporting bars, supporting rings, piezoelectric patches, probes and strain patches; the supporting rings are annular, one ends of the supporting bars are intersected in the centers of the supporting rings, the other ends of the supporting bars are uniformly fixed on the supporting rings respectively, and the supporting bars are even in number to form a centrosymmetric structure; each support bar is provided with a piezoelectric sheet; arranging strain gauges on the upper parts of the intersection points of the plurality of supporting strips; a conical probe is arranged at the lower part of the intersection point; the piezoelectric unit structures are arranged on the inner surface of the support frame; the probe of each piezoelectric unit structure is contacted with a sample to be detected; the piezoelectric sheet detects a frequency response curve of a piezoelectric impedance parameter of the piezoelectric unit structure; the strain gauge detects the contact pressure between the probe and the sample.

The invention also aims to provide a mammary gland elastography detection system based on the piezoelectric impedance method.

The breast elasticity imaging detection system based on the piezoelectric impedance method comprises: the device comprises a detection array structure, a piezoelectric impedance tester, a strain gauge, a data acquisition card and a computer; the detection array structure comprises a plurality of piezoelectric unit structures and a support frame; each piezoelectric unit structure comprises a support ring, a plurality of support bars, a piezoelectric sheet, a strain gauge and a probe; the supporting rings are annular, one ends of the supporting bars are intersected in the centers of the supporting rings, the other ends of the supporting bars are uniformly fixed on the supporting rings respectively, and the supporting bars are even in number to form a centrosymmetric structure; each support bar is provided with a piezoelectric sheet; arranging strain gauges on the upper parts of the intersection points of the plurality of supporting strips; a conical probe is arranged at the lower part of the intersection point; the piezoelectric unit structures are arranged on the inner surface of the support frame and form a shape similar to the surface of a breast; the probe of each piezoelectric unit structure is contacted with a sample to be detected; the piezoelectric patch is connected to a piezoelectric impedance tester through a control line, and a frequency response curve of a piezoelectric impedance parameter of the piezoelectric unit structure is measured; the strain gauge is connected to a strain measuring instrument through a control line, and the contact pressure between the probe and the sample is detected; the electrical impedance tester and the strain gauge are respectively connected to the data acquisition card; the data acquisition card is connected to the computer.

The invention adopts a plurality of piezoelectric unit structures arranged on the inner surface of the support frame to form a shape similar to the surface of a breast, and the piezoelectric unit structures are placed on a sample to be detected, namely breast tissue to be detected; in the detection process, the support frame provides support for the piezoelectric unit structures, and the distance between the support frame and the piezoelectric unit structures can be adjusted, so that the probe is contacted with a sample to be detected; the probe of each piezoelectric unit structure is contacted with a sample to be detected; the strain gauge detects the contact pressure between the probe and a sample to be detected; the strain gauge measures to obtain contact pressure, and the contact pressure is adjusted by adjusting the distance between the piezoelectric unit structure and the support frame; the piezoelectric impedance tester measures the frequency response curve of the piezoelectric impedance parameters (the piezoelectric impedance parameters comprise admittance G, phase theta and impedance Z) of each piezoelectric unit structure to obtain the resonance frequency of the piezoelectric impedance parameters; establishing a relation between the resonance frequency of the piezoelectric impedance parameters of the piezoelectric unit structures and the Young modulus of the contact points, and thus calculating to obtain the local Young modulus of the sample to be detected, which is detected by each piezoelectric unit structure; and summarizing and integrating the local Young modulus obtained by all the piezoelectric unit structures according to the spatial positions corresponding to the piezoelectric unit structures to form a Young modulus distribution map, wherein the Young modulus distribution map is the Young modulus distribution of the mammary gland, and further the health state of the tissue is diagnosed.

In the piezoelectric unit structure, a piezoelectric sheet is arranged on one surface of each support bar which is centrosymmetrically distributed to form a single crystal piezoelectric unit structure; or, the upper surface and the lower surface of each support strip which is centrosymmetric are respectively provided with a piezoelectric sheet to form a double-crystal piezoelectric unit structure.

The plurality of piezoelectric unit structures are arranged on the inner surface of the support frame, the needle points of the probes are in contact with the surface of the breast tissue to be detected by adjusting the distance between the piezoelectric unit structures and the support frame, so that the curved surface formed by the needle points of the probes is consistent with the surface of the breast, the shape of the curved surface is similar to that of the surface of the breast, and the breast tissue to be detected can be conveniently placed on the breast tissue to be detected.

Each piezoelectric patch in the plurality of piezoelectric unit structures is respectively connected to one channel of the piezoelectric impedance tester through a control line; each strain gauge in the plurality of piezoelectric unit structures is connected to one channel of the strain gauge through a control line; the invention integrates a plurality of control lines on the support frame, and then the support frame is respectively connected to the piezoelectric impedance tester and the strain gauge, thereby realizing that each piezoelectric sheet is respectively connected to a channel of the piezoelectric impedance tester through the control line, and each strain sheet is respectively connected to a channel of the strain gauge through the control line.

The invention further aims to provide a mammary gland elastography detection method based on the piezoelectric impedance method.

The invention discloses a mammary gland elastography detection method based on a piezoelectric impedance method, which comprises the following steps:

1) placing the detection array structure on a sample to be detected, and enabling the probe of each piezoelectric unit structure to be in contact with the sample to be detected;

2) the strain gauge detects the contact pressure between the probe and the sample, the strain gauge measures the contact pressure, and the contact pressure is adjusted by adjusting the distance between the piezoelectric unit structure and the support frame;

3) the piezoelectric impedance tester measures the frequency response curve of the piezoelectric impedance parameters of each piezoelectric unit structure to obtain the resonance frequency of the piezoelectric impedance parameters, and the strain gauge measures the contact pressure between the probe and the sample;

4) the data acquisition card acquires and respectively acquires the resonance frequency measured by the piezoelectric impedance tester and the value of the contact pressure measured by the strain gauge and transmits the values to the computer;

5) and the computer calculates and obtains local elasticity information measured by each piezoelectric unit structure in contact with the sample to be measured according to the values of the resonance frequency and the contact pressure, the established piezoelectric equivalent circuit model and the obtained analytic mechanical relation formula, and summarizes and integrates the local elasticity information obtained by all the piezoelectric unit structures according to the spatial positions corresponding to the piezoelectric unit structures to form an elasticity information distribution diagram, so that the health degree of the sample is judged.

Wherein, in step 5), the elasticity information comprises an elasticity property k_tAnd Young's modulus E_xResonance frequency f of piezoelectric unit structure₀And elastic properties k_tSatisfies the following relation:

$k_t=m_t{\mathrm{\ω}}_0^2+{\stackrel{\‾}{k}}_b{\mathrm{\λ}}_{b0}^3\frac{1+\cos {\mathrm{\λ}}_{b0}L\cosh {\mathrm{\λ}}_{b0}L}{\sin {\mathrm{\λ}}_{b0}L\cosh {\mathrm{\λ}}_{b0}\text{L-cos}{\mathrm{\λ}}_{b0}L\sinh {\mathrm{\λ}}_{b0}L}$

wherein, ω is₀＝2πf₀，m_tL is the radius of the piezoelectric unit structure, lambda, is the mass of the probe_b0In order to be an equivalent wavelength of the light,equivalent beam stiffness.

Further, according to the Hertz contact theory, the Young modulus E of the sample to be measured can be obtained_xSatisfies the following formula:

$E_x=\frac{E_t\sqrt{\frac{{\left(k_t\right)}^3}{6\mathrm{RF}}}}{\sqrt{\frac{{\left(k_t\right)}^3}{6\mathrm{RF}}}-E_t}$

wherein E is_tIs the Young's modulus of the probe, R is the radius of the probe, and F is the contact pressure.

THE ADVANTAGES OF THE PRESENT INVENTION

Compared with the traditional cantilever beam type elastography system, the brand-new mammary gland elastography detection system based on the piezoelectric impedance method provided by the invention has the following differences and advantages:

the invention designs a brand-new piezoelectric unit structure and a detection array structure, the shape of the detection array structure is similar to the surface of a breast and can be worn on the human breast to be detected, and the analytic relation between the resonance frequency of the piezoelectric unit structure and the elastic information of a sample to be detected is obtained by measuring the resonance frequency of piezoelectric parameters such as admittance and phase of the piezoelectric unit structure and according to a corresponding established piezoelectric equivalent circuit model based on a piezoelectric impedance method. In the traditional method, a piezoelectric cantilever beam is adopted, based on the mechanical resonance principle, the relation between the mechanical vibration frequency and a sample to be measured is measured through strain tracking and according to an established mechanical balance model.

The piezoelectric unit structure-based measurement device has the advantages that based on the piezoelectric unit structure measurement, the stability is higher, the device is not easily interfered by external vibration, the applied measurement voltage is less than 1V, the force and vibration amplitude are smaller, and an object to be measured cannot feel vibration caused by the test; the traditional method adopts strain tracking, needs to use higher voltage (generally more than 500V) to excite the cantilever beam to generate measurable strain, so that the measurement of contacting with the skin has larger electric leakage risk, and the traditional method adopts a pure mechanical balance model to describe piezoelectric vibration, has larger theoretical error and brings larger measurement error.

The invention uses a specially designed piezoelectric unit structure, integrates the piezoelectric unit structure into a medical detection array structure suitable for mammary tissue, builds a detection system according to the structure, and provides a mammary health detection method based on the detection system. Compared with other medical detection means, the detection method has strong specificity, can give quantitative detection results, is more suitable for the breast cancer with cancerous tissues on the superficial layer due to the special design, and solves the difficult problem of detection of the superficial tissues which is difficult to finish by ultrasonic elastography. The invention is simple and reliable, can assist medical staff to carry out physical examination, can also miniaturize the medical staff, is suitable for daily physical self-examination in families, and is beneficial to early discovery and early treatment of related diseases of mammary glands.

Drawings

Fig. 1 is a schematic structural diagram of a piezoelectric unit structure of the present invention, wherein (a) is a schematic structural diagram of four crossed single-crystal piezoelectric unit structures, (b) is a schematic structural diagram of four crossed twin-crystal piezoelectric unit structures, (c) is a schematic structural diagram of six 60 ° crossed single-crystal piezoelectric unit structures, and (d) is a schematic structural diagram of six 60 ° crossed twin-crystal piezoelectric unit structures;

FIG. 2 is a schematic structural diagram of a plurality of piezoelectric units distributed on a sample to be tested according to the present invention;

FIG. 3 is a schematic diagram of the structure of a breast elastography detection array based on a piezoelectric impedance method according to the present invention;

FIG. 4 is a schematic diagram of one embodiment of a breast elastography detection system based on a piezoelectric impedance method of the present invention;

FIG. 5 is a schematic diagram of a bimorph piezoelectric unit structure equivalent to a bimorph beam contact vibration model according to the present invention;

fig. 6 is a piezoelectric equivalent circuit diagram of a bimorph beam contact vibration model equivalent to the bimorph piezoelectric unit structure shown in fig. 5.

Detailed Description

The invention will be further elucidated by means of specific embodiments in the following with reference to the drawing.

As shown in fig. 1, the piezoelectric unit structure includes a plurality of support bars 21, a support ring 22, a piezoelectric sheet 23, a probe 24, and a strain gauge 25; the supporting strips 21 are long-strip-shaped, the supporting ring 22 is circular, one ends of the supporting strips 21 are intersected in the center of the supporting ring 22, the other ends of the supporting strips 21 are respectively and uniformly fixed on the supporting ring 22, and the supporting strips 21 are even in number to form a centrosymmetric structure; each support strip 21 is provided with a piezoelectric sheet 23; a strain gauge 25 is arranged above the intersection point of the support bars; a tapered probe 24 is provided at the lower part of the intersection. Piezoelectric sheets 23 can be arranged on one surface of the support bars which are distributed in the central symmetry to form a single crystal piezoelectric unit structure; or, the piezoelectric sheets 23 are respectively arranged on the upper surface and the lower surface of the support bar with central symmetry to form a bimorph piezoelectric unit structure. In fig. 1, (a) is a schematic diagram of a structure of four crossed single crystal piezoelectric units, (b) is a schematic diagram of a structure of four crossed double crystal piezoelectric units, (c) is a schematic diagram of a structure of six 60 ° crossed single crystal piezoelectric units, and (d) is a schematic diagram of a structure of six 60 ° crossed double crystal piezoelectric units.

As shown in fig. 2, a plurality of piezoelectric unit structures 2 are uniformly distributed on a curved surface of a semi-ellipsoid to form a shape similar to the surface of a breast, and can be worn on a breast tissue to be measured.

As shown in fig. 3, the breast elastography detecting array structure based on the piezoelectric impedance method of this embodiment includes: a plurality of piezoelectric unit structures 2 and a support frame 1; a plurality of piezoelectric unit structures 2 are arranged on the inner surface of the support frame 1 to form a shape similar to the surface of a breast, and the contact pressure between the probe and a sample to be measured is adjusted by adjusting the distance between the piezoelectric unit structures and the support frame.

As shown in fig. 4, the breast elastography detection system based on the piezoelectric impedance method of the present embodiment includes: the device comprises a detection array structure, a piezoelectric impedance tester 3, a strain gauge 4, a data acquisition card 5 and a computer 6; the probe of each piezoelectric unit structure is contacted with a sample to be detected; a plurality of control lines are integrated on the support frame 1, and then the support frame 1 is respectively connected to the piezoelectric impedance tester 3 and the strain gauge 4, so that the piezoelectric patches of each piezoelectric unit structure are respectively connected to one channel of the piezoelectric impedance tester 3 through the control lines, and each strain patch is respectively connected to one channel of the strain gauge 4 through the control lines; the electrical impedance tester 3 and the strain gauge 4 are respectively connected to the data acquisition card 5; the data acquisition card 5 is connected to a computer 6.

The bimorph piezoelectric unit structure is equivalent to a bimorph beam contact vibration model shown in fig. 5, and a piezoelectric equivalent circuit diagram is thus established, as shown in fig. 6. The detection method of the invention is based on the piezoelectric impedance method and establishes a piezoelectric equivalent circuit model to calculate the resonant frequency f of the piezoelectric unit structure₀And elastic properties k of the sample_tAnd Young's modulus E of the sample_xThe detection principle of the present invention is described below.

For the piezoelectric unit structure shown in fig. 1, it is essentially a centrosymmetric structure, so when describing the contact vibration with the sample to be measured, it can be simplified to a piezoelectric bimorph beam contact vibration model as shown in fig. 5, where L is the radius of the piezoelectric unit structure, and m is the radius of the piezoelectric unit structure_tIs the mass of the probe, h_sIs half the thickness of the probe metal layer, h_pIs the thickness of the piezoelectric sheet. In FIG. 5, the contact between the probe and the sample of the piezoelectric unit structure is performed using a stiffness k_tThe parameters include the elastic properties of the sample.

Resonance frequency f of piezoelectric unit structure₀And elastic properties k of the sample_tThe relationship between them can be obtained by an equivalent circuit as shown in fig. 6, whose impedance matrix is:

$\left\{\begin{array}{c}{F}_1\\ F_2\\ F_3\\ F_4\\ V\end{array}\right\}=\left[\begin{array}{ccccc}{Z}_{11}& Z_{12}& Z_{13}& Z_{14}& Z_{15}\\ & Z_{22}& Z_{23}& Z_{24}& Z_{25}\\ & & Z_{33}& Z_{34}& Z_{35}\\ & \mathrm{Symm}& & Z_{44}& Z_{45}\\ & & & & Z_{55}\end{array}\right]\left\{\begin{array}{c}{U}_1\\ U_2\\ U_3\\ U_4\\ I\end{array}\right\}---\left(1\right)$

wherein, F₁As a shear boundary condition of the clamped ends, F₂For the boundary condition of bending moment at the clamped end, F₃As a free end shear boundary condition, F₄As a free-end bending moment boundary condition, U₁For fast branch speed boundary conditions, U₂For the fixed-branch-end angular velocity boundary condition, U₃As a free end velocity boundary condition, U₄V and I are the voltage and the current loaded on the piezoelectric sheet by the piezoelectric impedance tester respectively for the free end angular velocity boundary condition. Symm indicates that the matrix is a symmetric matrix, and each impedance element in the matrix can be represented as:

$Z_{11}=Z_{33}=\frac{{\stackrel{\‾}{K}}_b{\mathrm{\λ}}_b^3}{\mathrm{j\ω}}\frac{-\mathrm{cn}-\mathrm{sm}}{1-\mathrm{cm}}$

$Z_{12}=-Z_{34}=\frac{{\stackrel{\‾}{K}}_b{\mathrm{\λ}}_b^2}{\mathrm{j\ω}}\frac{\mathrm{sn}}{1-\mathrm{cm}}$

$Z_{13}=\frac{{\stackrel{\‾}{K}}_b{\mathrm{\λ}}_b^3}{\mathrm{j\ω}}\frac{s+n}{1-\mathrm{cm}}$

$Z_{14}=-Z_{23}=\frac{{\stackrel{\‾}{K}}_b{\mathrm{\λ}}_b^2}{\mathrm{j\ω}}\frac{-c+m}{1-\mathrm{cm}}$

Z₁₅＝Z₃₅＝0 (2)

$Z_{22}=Z_{44}=\frac{{\stackrel{\‾}{K}}_b{\mathrm{\λ}}_b}{\mathrm{j\ω}}\frac{\mathrm{cn}-\mathrm{sm}}{1-\mathrm{cm}}+\frac{N^2}{\mathrm{j\ω}{C}_c}$

$Z_{24}=\frac{{\stackrel{\‾}{K}}_b{\mathrm{\λ}}_b}{\mathrm{j\ω}}\frac{s-n}{1-\mathrm{cm}}-\frac{N^2}{\mathrm{j\ω}{C}_c}$

$Z_{25}=-Z_{45}=\frac{N}{\mathrm{j\ω}{C}_c}$

$Z_{55}=\frac{1}{\mathrm{j\ω}{C}_c}$

where ω is the vibration angular frequency and has ω 2 π f, f is the vibration frequency, and the equivalent depth ${\stackrel{\‾}{K}}_b=\frac{2}{3}\mathrm{\ω}[\frac{1}{S_{p_{11}}^E}({(h_p+h_s)}^3-h_s^3)+\frac{1}{S_{s_{11}}}{h}_s^3],N=-\frac{d_{31}}{S_{p_{11}}^E}\mathrm{\ω}\left(\frac{h_p+2h_s}{2}\right),$ d₃₁And S_s11Respective material parameter, equivalent wavelengthρ_pAnd ρ_sC ═ cos λ, the densities of the piezoelectric sheet and the supporting strips, respectively_bL，s＝sinλ_bL，m＝coshλ_bL，n＝sinhλ_bL, capacitance of piezoelectric beamp₃₃Is the dielectric constant of the piezoelectric sheet, N is the transformation coefficient, and the meaning of each impedance element in fig. 6 is:

Z_c＝Z₁₁+Z₁₂+Z₁₃-Z₁₄

Z_d＝Z₁₂+Z₁₄+Z₂₂+Z₂₄Z_e＝-Z₁₄-Z₂₄Z_f＝-Z₁₂+Z₁₄(3)

Z_g＝Z₁₂Z_h＝-Z₁₂-Z₁₄Z_i＝-Z₁₃+Z₁₄

C_m＝-C_c/N²

according to the equivalent circuit theory, the relationship between the admittance Y and the vibration angular frequency ω in fig. 6 can be expressed as:

$Y=\mathrm{j\ω}(C_c+\frac{N^2}{{\stackrel{\‾}{K}}_b{\mathrm{\λ}}_b}\frac{-\mathrm{cn}-\mathrm{sm}-\mathrm{cm\β}+\mathrm{\β}}{1+\mathrm{cm}-\mathrm{sm\β}+\mathrm{cn\β}})---\left(4\right)$

wherein, $\mathrm{\β}=\frac{-{\mathrm{\ω}}^2{m}_t+k_t}{{\stackrel{\‾}{K}}_b{\mathrm{\λ}}_b^3}.$

the oscillation frequency of the circuit when the admittance Y is at the maximum is the resonance frequency, i.e. the formula (4) is at omega₀＝2πf₀Taking the maximum value of f₀Is the resonance frequencyAt this time, β satisfies 1+ cm-sm β + cn β as 0, and therefore:

$k_t=m_t{\mathrm{\ω}}_0^2+{\stackrel{\‾}{k}}_b{\mathrm{\λ}}_{b0}^3\frac{1+\cos {\mathrm{\λ}}_{b0}L\cosh {\mathrm{\λ}}_{b0}L}{\sin {\mathrm{\λ}}_{b0}L\cosh {\mathrm{\λ}}_{b0}\text{L-cos}{\mathrm{\λ}}_{b0}L\sinh {\mathrm{\λ}}_{b0}L}---\left(5\right)$

wherein,further, according to the Hertz contact theory, the Young modulus E of the sample to be measured can be obtained_xExpression (c):

$E_x=\frac{E_t\sqrt{\frac{{\left(k_t\right)}^3}{6\mathrm{RF}}}}{\sqrt{\frac{{\left(k_t\right)}^3}{6\mathrm{RF}}}-E_t}---\left(6\right)$

in the formula, E_tThese parameters are known as the Young's modulus of the probe, R as the radius of the probe, and F as the contact pressure. Thereby obtaining the resonant frequency f of the piezoelectric unit structure₀Then, k is calculated from equation (5)_tFurther calculating the Young modulus E of the sample to be measured according to the formula (6)_xThe above equations (5) and (6) are equations for calculating the resonant frequency f of the piezoelectric unit structure based on the piezoelectric impedance method₀And analyzing the mechanical relationship with the elastic information of the sample to be detected.

The invention discloses a mammary gland elastography detection method based on a piezoelectric impedance method, which comprises the following steps:

1) placing the detection array structure on a sample to be detected, and enabling the probe of each piezoelectric unit structure to be in contact with the sample to be detected;

2) the strain gauge detects the contact pressure between the probe and the sample, the strain gauge measures the contact pressure, and the contact pressure is adjusted by adjusting the distance between the piezoelectric unit structure and the support frame;

3) the piezoelectric impedance tester measures the frequency response curve of the piezoelectric impedance parameters of each piezoelectric unit structure to obtain the resonance frequency of the piezoelectric impedance parameters, and the strain gauge measures the contact pressure between the probe and the sample;

4) the data acquisition card acquires and respectively acquires the resonance frequency measured by the piezoelectric impedance tester and the value of the contact pressure measured by the strain gauge and transmits the values to the computer;

5) and the computer calculates and obtains local elasticity information measured by each piezoelectric unit structure in contact with the sample to be measured according to the values of the resonance frequency and the contact pressure, the established piezoelectric equivalent circuit model and the obtained analytic mechanical relation formula, and summarizes and integrates the local elasticity information obtained by all the piezoelectric unit structures according to the spatial positions corresponding to the piezoelectric unit structures to form an elasticity information distribution diagram, so that the health degree of the sample is judged.

Finally, it is noted that the disclosed embodiments are intended to aid in further understanding of the invention, but those skilled in the art will appreciate that: various substitutions and modifications are possible without departing from the spirit and scope of the invention and the appended claims. Therefore, the invention should not be limited to the embodiments disclosed, but the scope of the invention is defined by the appended claims.

Claims (5)

1. A breast elastography detection array structure, the detection array structure comprising: a plurality of piezoelectric unit structures and a support frame; each piezoelectric unit structure comprises a plurality of supporting bars, supporting rings, piezoelectric patches, probes and strain patches; the supporting rings are annular, one ends of the supporting bars are intersected in the centers of the supporting rings, the other ends of the supporting bars are uniformly fixed on the supporting rings respectively, and the supporting bars are even in number to form a centrosymmetric structure; each support bar is provided with a piezoelectric sheet; arranging strain gauges on the upper parts of the intersection points of the plurality of supporting strips; a conical probe is arranged at the lower part of the intersection point; the piezoelectric unit structures are arranged on the inner surface of the support frame; the probe of each piezoelectric unit structure is contacted with a sample to be detected; the piezoelectric sheet detects a frequency response curve of a piezoelectric impedance parameter of the piezoelectric unit structure; the strain gauge detects the contact pressure between the probe and the sample.

2. The probing array structure of claim 1, wherein the contact pressure between the probe and the sample to be tested is adjusted by adjusting the distance between the piezoelectric unit structure and the supporting frame.

3. The probe array structure according to claim 1, wherein in the piezoelectric unit structure, a piezoelectric sheet is disposed on one surface of each support bar which is centrosymmetrically distributed to form a single crystal piezoelectric unit structure; or, the upper surface and the lower surface of each support strip which is centrosymmetric are respectively provided with a piezoelectric sheet to form a double-crystal piezoelectric unit structure.

4. A breast elastography detection system, the detection system comprising: the device comprises a detection array structure, a piezoelectric impedance tester, a strain gauge, a data acquisition card and a computer; the detection array structure comprises a plurality of piezoelectric unit structures and a support frame; each piezoelectric unit structure comprises a support ring, a plurality of support bars, a piezoelectric sheet, a strain gauge and a probe; wherein,

the supporting strips are long-strip-shaped, the supporting ring is circular, one ends of the supporting strips are intersected in the center of the supporting ring, the other ends of the supporting strips are uniformly fixed on the supporting ring respectively, and the supporting strips are even in number to form a centrosymmetric structure; each support bar is provided with a piezoelectric sheet; arranging strain gauges on the upper parts of the intersection points of the plurality of supporting strips; a conical probe is arranged at the lower part of the intersection point; the piezoelectric unit structures are arranged on the inner surface of the support frame; the probe of each piezoelectric unit structure is contacted with a sample to be detected;

the piezoelectric patch is connected to a piezoelectric impedance tester through a control line, and a frequency response curve of a piezoelectric impedance parameter of the piezoelectric unit structure is measured;

the strain gauge is connected to a strain measuring instrument through a control line, and the contact pressure between the probe and the sample is detected; the piezoelectric impedance tester and the strain gauge are respectively connected to the data acquisition card; the data acquisition card is connected to the computer.

5. A test system as claimed in claim 4 wherein the plurality of control lines are integrated on a support frame which is connected to the piezoelectric impedance tester and the strain gauge respectively, whereby each piezoelectric patch is connected to a channel of the piezoelectric impedance tester via a control line and each strain patch is connected to a channel of the strain gauge via a control line.