Photoacoustic / ultrasonic bimodal tissue-imitating phantom material and preparation method thereof

Abstract

The invention discloses an opto-acoustic / ultrasonic dual-mode tissue-imitating phantom material and a preparation method of the opto-acoustic / ultrasonic dual-mode tissue-imitating phantom material. The opto-acoustic / ultrasonic bimodal tissue-like phantom material is prepared from the following raw materials in percentage by mass: 10 to 15 percent of polyvinyl alcohol, 2 to 5 percent of a first cross-linking agent, 10 to 12 percent of a water-soluble organic solvent, 1 to 3 percent of an initiator, 5 to 7 percent of a second cross-linking agent and the balance of water, the first cross-linking agent comprises one or more than two of carboxymethyl cellulose sodium, glucose, boric acid and adipic acid; the second cross-linking agent is an amide compound.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and more specifically, to a photoacoustic / ultrasonic dual-mode tissue-mimicking phantom material and a preparation method thereof. Background Art

[0002] Photoacoustic imaging is a new type of non-invasive and non-ionizing biomedical imaging method developed in recent years. The basic principle of photoacoustic imaging is that when a pulsed laser is irradiated into biological tissue, the light absorption domain of the tissue will generate an ultrasonic signal. We call this ultrasonic signal generated by light excitation a photoacoustic signal. The photoacoustic signal generated by biological tissue carries the light absorption characteristic information of the tissue. By detecting the photoacoustic signal, the light absorption distribution image in the tissue can be reconstructed. Photoacoustic imaging combines the advantages of high selectivity in pure optical tissue imaging and deep penetration in pure ultrasonic tissue imaging, and can obtain high-resolution and high-contrast tissue images. In principle, it avoids the influence of light scattering, breaks through the "soft limit" (~1mm) of high-resolution optical imaging depth, and can achieve 50mm deep in vivo tissue imaging.

[0003] Ultrasonic tissue phantoms are similar to biological tissues in terms of ultrasonic properties and are mainly used for the correction, inspection, and in vitro learning and training of ultrasonic products. Cardiovascular-specific ultrasonic tissue phantoms include a heart phantom with ultrasonic properties similar to those of heart tissue and a blood flow channel located inside the phantom. A pump is used to make the simulated blood fluid flow in the blood flow channel to simulate the blood flow in the heart. However, existing heart phantom materials can only simulate pure ultrasonic imaging and are not suitable for photoacoustic imaging technology. Summary of the invention

[0004] The purpose of the present invention is to overcome the above-mentioned defects in the prior art and to provide a photoacoustic / ultrasonic dual-modal tissue-mimicking phantom material and a preparation method thereof.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] A photoacoustic / ultrasonic dual-mode tissue-mimicking phantom material, the raw materials of which include the following components in percentage by mass:

[0007] 5% to 35% of polyvinyl alcohol, 2% to 5% of a first crosslinking agent, 10% to 12% of a water-soluble organic solvent, 1% to 3% of an initiator, 5% to 7% of a second crosslinking agent and the balance of water;

[0008] The first cross-linking agent includes one or more of sodium hydroxymethyl cellulose, glucose, boric acid, and adipic acid;

[0009] The second cross-linking agent is an amide compound.

[0010] The present invention also discloses a method for preparing the above-mentioned photoacoustic / ultrasonic dual-modal tissue-mimicking phantom material, comprising the following process:

[0011] Dissolving polyvinyl alcohol in water and heating to obtain polyvinyl alcohol hydrogel;

[0012] adding a first cross-linking agent into the polyvinyl alcohol hydrogel and mixing them to obtain a first cross-linked product;

[0013] adding a second crosslinking agent and an initiator to the first crosslinked product to carry out a chemical crosslinking reaction to obtain a second crosslinked product;

[0014] performing ultrasonic homogenization on the second cross-linked product to obtain a homogeneous copolymer solution;

[0015] A water-soluble organic solvent is added to the homogeneous copolymer solution and mixed to obtain a freezing liquid, which is poured into a mold for freezing, and then thawed after freezing, and the freezing and thawing are repeated to obtain the photoacoustic / ultrasonic dual-modality tissue-mimicking phantom material.

[0016] Implementing the embodiments of the present invention will have the following beneficial effects:

[0017] In the embodiment of the present invention, the strength of polyvinyl alcohol can be enhanced by the first cross-linking agent. The first cross-linking agent is also a thickener, a dispersant and a stabilizer, which can enhance the viscosity, strength, dispersibility and stability of polyvinyl alcohol, reduce ionic polyvinyl alcohol, and improve the dispersion uniformity of polyvinyl alcohol, so as to facilitate the later acquisition of a homogeneous porous three-dimensional network structure; then, the second cross-linking agent is chemically grafted and copolymerized with polyvinyl alcohol and the first cross-linking agent to form a three-dimensional network copolymer structure, and the amide compound can enhance the crystallinity, transparency and mechanical strength of the copolymer by chemical grafting; by adding a water-soluble organic solvent to the freezing liquid, the water-soluble organic solvent can be soluble in water, and can have good compatibility and binding with organic impurities such as polyvinyl alcohol with a lower alcoholysis degree that are not involved in the three-dimensional network copolymer structure, and can be replaced by water in the freeze-thaw cycle, thereby further improving the transmittance of the phantom, and also further improving the homogeneity of the phantom.

[0018] The present invention can obtain a high-transmittance phantom through the combined effect of chemical grafting of the second cross-linking agent and removal of organic impurities by a water-soluble organic solvent during a freeze-thaw cycle, thereby being able to apply a photoacoustic / ultrasound dual-modality imaging technique.

[0019] The acoustic impedance of the photoacoustic / ultrasonic dual-mode tissue-mimicking phantom material of the present invention is 1.5 MRayls, the sound velocity is close to 1540 m / s of human soft tissue, and the sound attenuation is close to 0.5 dB / MHz.cm, which is close to the ultrasonic characteristics of human heart tissue. It can be used in endoscopic ultrasound systems such as intracardiac ultrasound (ICE) and transesophageal ultrasound (TEE) or photoacoustic systems for blood flow simulation and function calibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] in:

[0022] Figure 1 This is a transparency photograph of the tissue-mimicking phantom material prepared in Example 1 on a black substrate.

[0023] Figure 2 This is a transparency photograph of the tissue-mimicking phantom material prepared in Comparative Example 1 on a black substrate.

[0024] Figure 3 This is a transparency photograph of the tissue-mimicking phantom material prepared in Comparative Example 2 on a black substrate.

[0025] Figure 4 This is a transparency photograph of the tissue-mimicking phantom material prepared in Comparative Example 3 on a black substrate.

[0026] Figure 5 This is a transparency photograph of the tissue-mimicking phantom material prepared in Comparative Example 4 on a black substrate.

[0027] Figure 6 This is a transparency photograph of the tissue-mimicking phantom material prepared in Comparative Example 5 on a black substrate. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] The present invention discloses a photoacoustic / ultrasonic dual-mode tissue-mimicking phantom material, the raw materials of which include the following components in percentage by mass:

[0030] 5% to 35% polyvinyl alcohol, 2% to 5% first crosslinking agent, 10% to 12% water-soluble organic solvent, 1% to 3% initiator, 5% to 7% second crosslinking agent and balance water. The first crosslinking agent includes one or more of sodium hydroxymethyl cellulose, glucose, boric acid and adipic acid; the second crosslinking agent is an amide compound.

[0031] In the embodiment of the present invention, the strength of polyvinyl alcohol can be enhanced by the first cross-linking agent. The first cross-linking agent is also a thickener, a dispersant and a stabilizer, which can enhance the viscosity, strength, dispersibility and stability of polyvinyl alcohol, reduce ionic polyvinyl alcohol, and improve the dispersion uniformity of polyvinyl alcohol, so as to facilitate the later acquisition of a homogeneous porous three-dimensional network structure; then, the second cross-linking agent is chemically grafted and copolymerized with polyvinyl alcohol and the first cross-linking agent to form a three-dimensional network copolymer structure, and the amide compound can enhance the crystallinity, transparency and mechanical strength of the copolymer by chemical grafting; by adding a water-soluble organic solvent to the freezing liquid, the water-soluble organic solvent can be soluble in water, and can have good compatibility and binding with organic impurities such as polyvinyl alcohol with a lower alcoholysis degree that are not involved in the three-dimensional network copolymer structure, and can be replaced by water in the freeze-thaw cycle, thereby further improving the transmittance of the phantom, and also further improving the homogeneity of the phantom.

[0032] The present invention can obtain a high-transmittance phantom through the combined effect of chemical grafting of the second cross-linking agent and removal of organic impurities by a water-soluble organic solvent during a freeze-thaw cycle, thereby being able to apply a photoacoustic / ultrasound dual-modality imaging technique.

[0033] The acoustic impedance of the photoacoustic / ultrasonic dual-mode tissue-mimicking phantom material of the present invention is 1.5 MRayls, the sound velocity is close to 1540 m / s of human soft tissue, and the sound attenuation is close to 0.5 dB / MHz.cm, which is close to the ultrasonic characteristics of human heart tissue. It can be used in endoscopic ultrasound systems such as intracardiac ultrasound (ICE) and transesophageal ultrasound (TEE) or photoacoustic systems for blood flow simulation and function calibration.

[0034] In a specific embodiment, the amide compound is preferably an amide compound containing a carbon-carbon double bond. Specifically, the amide compound may include one or more of acrylamide and N,N-methylenebisacrylamide.

[0035] In a specific embodiment, the polyvinyl alcohol includes one or more of PVA1699, PVA1799, and PVA2699.

[0036] The initiator is used to initiate a crosslinking reaction between the polyvinyl alcohol, the first crosslinking agent and the second crosslinking agent to generate a three-dimensional network polymer. The initiator can be any initiator that initiates a crosslinking reaction. In a specific embodiment, the initiator includes one or more of ammonium persulfate, undecane diammonium, and diethylenetriamine.

[0037] The water-soluble organic solvent is soluble in water and has high binding and compatibility with polyvinyl alcohol with low alcoholysis degree and other organic impurities that are not involved in forming a three-dimensional network structure. It can be replaced by water during the freeze-thaw cycle, thereby further improving the light transmittance of the phantom and the homogeneity of the phantom. In a specific embodiment, the water-soluble organic solvent includes one or more of dimethyl sulfoxide, ethylene glycol, ethylenediamine, dimethylformamide and glycerol.

[0038] In a specific embodiment, the raw material also includes a defoamer with a mass percentage of 1% to 5%, and the defoamer is used to eliminate fine bubbles and maintain the stability of the system. Specifically, the defoamer can include one or more of emulsified silicone oil, high carbon alcohol fatty acid ester, polydimethylsiloxane, and polyoxypropylene glycerol ether.

[0039] In a specific embodiment, the raw material further includes 1% to 3% by mass of a pH buffer solution, the pH value of the pH buffer solution ranges from 6.5 to 8.0, and the pH buffer solution is used to adjust the acid-base balance.

[0040] In a specific embodiment, the pH buffer includes one or more of PBS buffer, boric acid buffer, and potassium hydrogen phthalate buffer.

[0041] In a specific embodiment, the raw material further comprises 0.1% to 0.5% by mass of a toner. Preferably, the toner comprises a water-soluble dye.

[0042] The present invention also discloses a method for preparing the above-mentioned photoacoustic / ultrasonic dual-modal tissue-mimicking phantom material, comprising the following process:

[0043] 1) Dissolving polyvinyl alcohol in water and heating to obtain polyvinyl alcohol hydrogel.

[0044] In a specific embodiment, a vessel containing polyvinyl alcohol and water is placed in a water bath of an ultrasonic cleaner for heating. The water bath heating temperature is preferably 80°C to 100°C. The vessel is heated for 10min to 20min. The vessel is taken out and a magnetic stirrer is placed in the vessel for stirring. The water bath heating and stirring are repeated until a homogeneous, transparent polyvinyl alcohol hydrogel without flocculent precipitation is formed.

[0045] When the raw materials further include a toner, the toner may be added into the polyvinyl alcohol hydrogel for mixing before step 2).

[0046] 2) Adding a first cross-linking agent into the polyvinyl alcohol hydrogel and mixing the mixture to obtain a first cross-linked product.

[0047] In this process, the hydroxyl groups of polyvinyl alcohol and the hydroxyl groups of the first cross-linking agent are cross-linked through intermolecular hydrogen bonds. The first cross-linking agent is also a thickener, dispersant and stabilizer, which can enhance the viscosity, dispersibility and stability of polyvinyl alcohol, reduce ionic polyvinyl alcohol, improve the dispersion uniformity of polyvinyl alcohol, and facilitate the later acquisition of a homogeneous porous three-dimensional network structure.

[0048] When the raw materials further include a defoaming agent, in step 2), the defoaming agent and the first cross-linking agent can be added together into the polyvinyl alcohol hydrogel and mixed.

[0049] 3) Adding a second crosslinking agent and an initiator to the first crosslinked product to carry out a chemical crosslinking reaction to obtain a second crosslinked product.

[0050] In this process, the second crosslinking agents are chemically grafted with each other, and the second crosslinking agents are respectively grafted with polyvinyl alcohol and the first crosslinking agent to form a three-dimensional network copolymer. The second crosslinking agent can enhance the crystallinity, transparency and mechanical strength of the copolymer.

[0051] The initiator may be any initiator that initiates a crosslinking reaction. Preferably, the initiator is a photoinitiator. Specifically, the initiator includes one or more of ammonium persulfate, ammonium persulfate, undecanediammonium, and diethylenetriamine.

[0052] In a specific embodiment, the process of the chemical cross-linking reaction is: using ultraviolet light with a wavelength of 350nm to 400nm and a power of 30W to 50W to excite the initiator and perform chemical graft copolymerization.

[0053] 4) Ultrasonic homogenization is performed on the second cross-linked product to obtain a homogeneous copolymer solution.

[0054] The main function of ultrasonic homogenization is to make the three-dimensional network structure evenly and stably dispersed, and to improve the overall homogeneity and transparency of the phantom material.

[0055] In a specific embodiment, the ultrasonic homogenization process is: first use 40KHz~50KHz, 40W~60W ultrasonic sonication for 40min~80min, and then use 60KHz~100KHz, 40W~60W ultrasonic sonication for 40min~80min, so that the entire solution system is completely dissolved and the three-dimensional network structure is evenly and stably dispersed.

[0056] Preferably, in this process, a pH buffer is also added to the second cross-linked product to maintain the acid-base balance of the system, to prevent the reaction of the polyvinyl alcohol that is not fully alcoholyzed, and to maintain the stabilizer of the hydroxyl group.

[0057] 5) adding an organic solvent to the homogeneous copolymer solution and mixing to obtain a freezing liquid, pouring the freezing liquid into a mold for freezing, and then thawing after the freezing is completed, cyclically freezing and thawing to obtain a photoacoustic / ultrasound dual-modality tissue-mimicking phantom material.

[0058] In this process, the organic solvent has good compatibility and binding properties with polyvinyl alcohol with a lower degree of alcoholysis. In the subsequent freeze-thaw cycle, the organic solvent and the polyvinyl alcohol with a lower degree of alcoholysis combined with the organic solvent can also be replaced together with water, which not only increases the porosity and further improves the transmittance of the phantom, but also further improves the homogeneity of the phantom.

[0059] In a specific embodiment, the freezing temperature is -25°C to -15°C, the freezing time is 6h to 10h, the thawing temperature is room temperature (20°C to 30°C), the thawing time is 4h to 6h, and the number of freeze-thaw cycles is 2-3 times.

[0060] The final cross-linking of the phantom material of the present invention occurs during the temperature change process. Repeated freezing-thawing processes will form a three-dimensional network cross-linked structure. The temperature change has a gradient and time. Generally, the freezing temperature is -25°C to -15°C, and the freezing time is 6h to 10h; the thawing is carried out at room temperature (20°C to 30°C), and the thawing time is 4h to 6h.

[0061] The following are specific embodiments.

[0062] Example 1

[0063] A photoacoustic / ultrasonic dual-mode tissue-mimicking phantom material, the raw materials of which include the following components in percentage by mass:

[0064] 5% PVA1699, 2% sodium hydroxymethylcellulose, 10% dimethyl sulfoxide, 1% ammonium persulfate, 5% acrylamide, 1% emulsified silicone oil, 1% PBS buffer and the balance water.

[0065] The preparation method of the photoacoustic / ultrasonic dual-modality tissue-mimicking phantom material includes the following steps:

[0066] 1) Place the PVA1699 particles in a 500 mL plastic container, place the entire plastic container in an ultrasonic cleaning machine for water bath heating and turn on the ultrasonic wave, the water temperature is 100°C, and keep warm for 15 minutes.

[0067] 2) Take out the container, put in the stirring bar of the magnetic stirrer, and mix the PVA solution; repeat steps 1) and 2) until the mixed solution is transparent without flocculent precipitation. The overall stirring process takes about 1h to 1.5h.

[0068] 3) adding sodium hydroxymethyl cellulose and emulsified silicone oil to the PVA hydrogel prepared in step 2), stirring until the solution becomes clear, to obtain a first cross-linked product.

[0069] 4) Add acrylamide and ammonium persulfate, irradiate with 350-400 nm UV light at a power of 40 W for 10 minutes to obtain a second cross-linked product.

[0070] 5) Add PBS buffer, heat to 80°C, first sonicate with 45KHz, 50W ultrasound for 60 minutes, then change to 80KHz, 50W ultrasound for 60 minutes to obtain a homogeneous copolymer solution.

[0071] 6) adding dimethyl sulfoxide, stirring and removing bubbles to obtain a frozen liquid, pouring the frozen liquid into a mold for freezing, the freezing temperature is -20°C, freezing for 8 hours, and then naturally thawing at 25°C for 4 hours, and freezing and thawing cycles are repeated 3 times to obtain the photoacoustic / ultrasound dual-modal tissue-mimicking phantom material of the present invention.

[0072] Example 2

[0073] The difference between Example 2 and Example 1 is that the contents of the components are different, and the preparation process and parameters are exactly the same.

[0074] Specifically, a photoacoustic / ultrasonic dual-modal tissue-mimicking phantom material, the raw materials of which include the following components in percentage by mass:

[0075] 35% PVA1699, 5% sodium hydroxymethylcellulose, 12% dimethyl sulfoxide, 3% ammonium persulfate, 7% acrylamide, 5% emulsified silicone oil, 3% PBS buffer and the balance water.

[0076] Example 3

[0077] The difference between Example 3 and Example 1 is that the components are different, but the preparation process and parameters are exactly the same.

[0078] Specifically, a photoacoustic / ultrasonic dual-modal tissue-mimicking phantom material, the raw materials of which include the following components in percentage by mass:

[0079] 5% PVA2699, 2% glucose, 10% glycerol, 1% ammonium persulfate, 5% acrylamide, 1% emulsified silicone oil, 1% PBS buffer and the balance water.

[0080] Comparative Example 1

[0081] The difference between Comparative Example 1 and Example 1 is that the raw material components do not include acrylamide.

[0082] Comparative Example 2

[0083] The difference between Comparative Example 2 and Example 1 is that the components of the raw materials do not include dimethyl sulfoxide.

[0084] Comparative Example 3

[0085] The difference between Comparative Example 3 and Example 1 is that the raw material components do not include acrylamide and dimethyl sulfoxide.

[0086] Comparative Example 4

[0087] The difference between Comparative Example 4 and Example 1 is that the components of the raw materials do not include sodium hydroxymethyl cellulose.

[0088] Comparative Example 5

[0089] The only difference between Comparative Example 5 and Example 1 is that the preparation method does not include the step of ultrasonic homogenization.

[0090] Test Example 1

[0091] The acoustic performance indicators of the tissue-mimicking phantom materials prepared in Examples 1 to 3 and Comparative Examples 1 to 5 were tested respectively, and the sound velocity was tested by the transmission method. The specific testing process was as follows: 1) Two Olympus commercial transducers were used, and the transducers were placed in a sound-absorbing water tank; 2) The transmitter was a DPR300PR pulse transmitter-receiver, and the distance between the two transducers was adjusted using the penetration mode, and the transducers were in a one-transmit-one-receive mode; 3) The delay time displayed on the oscilloscope was checked, and this time was recorded as T0; 4) The prepared phantom material of a certain thickness was placed between the two transducers to ensure that the transducers were facing the phantom material; 5) The thickness d and T1 of the phantom material were recorded; 6) The formula d / C was used to calculate the delay time displayed on the oscilloscope, and the delay time was recorded as T0; 7) The phantom material of a certain thickness was placed between the two transducers to ensure that the transducers were facing the phantom material; 8) The thickness d and T1 of the phantom material were recorded; 9) The thickness d and T1 of the phantom material were recorded; 10) The thickness d and T1 of the phantom material were recorded; 11) The thickness d and T1 of the phantom material were recorded; 12) The thickness d and T1 of the phantom material were recorded; 13) The thickness d and T1 of the phantom material were recorded; 14) The thickness d and T1 of the phantom material were recorded; 15) The thickness d and T1 of the phantom material were recorded; 16) The thickness d and T1 of the phantom material were recorded; 17) The thickness d and T1 of the phantom material were recorded; 18) The thickness d and T1 of the phantom material were recorded water -d / C phantom =T0-T1, where C water is the speed of sound in water at room temperature of 25℃, which can be obtained by referring to relevant data, C phantom is the sound velocity of the phantom material; T0 and T1 are both values ​​that can be directly obtained on an oscilloscope. The acoustic properties of the tissue-mimicking phantom material obtained based on the above test process are shown in Table 1.

[0092] Table 1: Acoustic performance indicators of tissue-mimicking phantom materials

[0093]

[0094] From Table 1, it can be seen that the acoustic attenuation index of the tissue-mimicking phantom materials prepared in Examples 1 to 3 of the present invention meets the standard, which is less than 0.5 dB / MHz.cm, close to human heart tissue. However, the acoustic attenuation index of the phantom materials prepared in Comparative Examples 1 to 5 does not meet the standard.

[0095] Test Example 2

[0096] The tissue-mimicking phantom materials prepared in Example 1 and Comparative Examples 1 to 5 were placed on a black substrate, and then light was irradiated on the tissue-mimicking phantom materials. The transparency photos thereof are shown in FIG. Figure 1 to Figure 6 The transmittance range is shown in Table 1. Figure 1 It can be seen that the phantom material prepared in Example 1 has a black base under light, has a transmittance of more than 80%, and the phantom material is uniform, and the opaque polymer particles are small and uniformly dispersed. Comparative Example 1 does not include acrylamide, has a transmittance of <80%, and the phantom material is uneven. Comparative Example 2 does not include dimethyl sulfoxide, and has poor transmittance. Comparative Example 3 does not include acrylamide and dimethyl sulfoxide, and has poor transmittance. Comparative Example 4 does not include sodium hydroxymethyl cellulose, and it can be seen that there are obvious opaque agglomerates of uneven size in the phantom, which affects the transmittance. Comparative Example 5 does not perform ultrasonic homogenization, and it can be seen that there are also obvious opaque agglomerates of uneven size in the phantom, which affects the transmittance.

[0097] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A photoacoustic / ultrasonic dual-modal tissue-mimicking phantom material, characterized in that: The raw materials include the following components in percentage by mass: 5% to 35% of polyvinyl alcohol, 2% to 5% of a first crosslinking agent, 10% to 12% of a water-soluble organic solvent, 1% to 3% of an initiator, 5% to 7% of a second crosslinking agent and the balance of water; The first cross-linking agent includes one or more of sodium hydroxymethyl cellulose, glucose, boric acid, and adipic acid; The second cross-linking agent is an amide compound.

2. The photoacoustic / ultrasonic dual-modality tissue-mimicking phantom material according to claim 1, characterized in that: The initiator includes one or more of ammonium persulfate, undecane diammonium, and diethylenetriamine; The amide compound includes one or more of acrylamide and N,N-methylenebisacrylamide; The polyvinyl alcohol includes one or more of PVA1699, PVA1799 and PVA2699; The water-soluble organic solvent includes one or more of dimethyl sulfoxide, ethylene glycol, ethylenediamine, dimethylformamide and glycerol.

3. The photoacoustic / ultrasonic dual-modality tissue-mimicking phantom material according to claim 1 or 2, characterized in that: The raw materials also include a defoamer in an amount of 1% to 5% by mass.

4. The photoacoustic / ultrasonic dual-modality tissue-mimicking phantom material according to claim 3, characterized in that: The defoaming agent includes one or more of emulsified silicone oil, higher alcohol fatty acid ester, polydimethylsiloxane, and polyoxypropylene glycerol ether.

5. The photoacoustic / ultrasonic dual-modality tissue-mimicking phantom material according to claim 3, characterized in that: The raw material also includes 0.1% to 0.5% by mass of toner.

6. A method for preparing a photoacoustic / ultrasonic dual-modality tissue-mimicking phantom material, characterized in that: The process includes: Dissolving polyvinyl alcohol in water and heating to obtain polyvinyl alcohol hydrogel; adding a first cross-linking agent into the polyvinyl alcohol hydrogel and mixing them to obtain a first cross-linked product; adding a second crosslinking agent and an initiator to the first crosslinked product to carry out a chemical crosslinking reaction to obtain a second crosslinked product; performing ultrasonic homogenization on the second cross-linked product to obtain a homogeneous copolymer solution; A water-soluble organic solvent is added to the homogeneous copolymer solution and mixed to obtain a freezing liquid, which is poured into a mold for freezing, and then thawed after freezing, and the freezing and thawing are repeated to obtain the photoacoustic / ultrasonic dual-modality tissue-mimicking phantom material.

7. The preparation method according to claim 6, characterized in that: The process of the chemical cross-linking reaction is: using ultraviolet light with a wavelength of 350nm to 400nm and a power of 30W to 50W to excite the initiator.

8. The preparation method according to claim 6, characterized in that: The ultrasonic homogenization process is: firstly use 40KHz-50KHz, 40W-60W ultrasonic sonication for 40min-80min, and then use 60KHz-100KHz, 40W-60W ultrasonic sonication for 40min-80min.

9. The preparation method according to claim 6 or 8, characterized in that: During the ultrasonic homogenization process, a pH buffer solution is also added to the second cross-linked product, and the pH value of the pH buffer solution is in the range of 6.5 to 8.

0.

10. The preparation method according to claim 6, characterized in that: The freezing temperature is -25°C to -15°C, the freezing time is 6h to 10h, the thawing temperature is 20°C to 30°C, the thawing time is 4h to 6h, and the freezing and thawing cycles are 2-3 times.

Images