phantoms for magnetic resonance dielectric properties tomography and their fabrication methods

Abstract

This application relates to a phantom specifically designed for magnetic resonance dielectric property tomography and its fabrication method. By designing independent array unit functional areas, namely dielectric property array units, the dielectric properties of human tissue are simulated. Based on this, combined with the functions of traditional system phantoms, a phantom with array units simulating the dielectric properties of human tissue can be fabricated, enabling accurate evaluation of the MR EPT measurement process. Furthermore, the phantom fabrication process of this technical solution is low-cost and highly flexible, and can fabricate MR EPT-specific phantoms with high accuracy, stability, and repeatability, enabling performance evaluation of the same MR EPT technology on different magnetic resonance platforms.

Description

Technical Field

[0001] This application relates to the field of magnetic resonance phantom design and fabrication technology, and in particular to a phantom specifically for magnetic resonance dielectric property tomography and its fabrication method. Background Technology

[0002] With the development of magnetic resonance imaging (MRI) technology, many MRI techniques have emerged. Among them, MR EPT (Medium-to-Electrical Properties Tomography) is a magnetic resonance imaging method that has attracted much attention in recent years. This method can non-invasively measure the dielectric properties of biological tissues and detect changes in the dielectric properties of suspicious lesions, thereby providing imaging evidence for the early detection of tumor lesions and medical intervention, and improving patient survival rates.

[0003] Phantoms are recognized quality control standards; they are numerical or physical models that represent specific human structural features and can be used as quantitative tools. For safety, accuracy, and repeatability reasons, MRI phantoms are used to analyze, evaluate, and calibrate MRI systems and new technologies before they are applied to human trials.

[0004] However, current MRI phantoms are mainly used for qualitative measurement of MRI system evaluation, such as basic imaging quality parameters of the MRI system, such as signal-to-noise ratio, spatial resolution, slice thickness, and geometric distortion. MR EPT technology is a quantitative measurement technique, and existing MRI phantoms cannot accurately evaluate the MR EPT measurement process. Summary of the Invention

[0005] Based on this, it is necessary to provide a special phantom for magnetic resonance dielectric tomography and a method for preparing a special phantom for magnetic resonance dielectric tomography, in order to address the above-mentioned technical problems and prepare a special phantom for magnetic resonance dielectric tomography that can accurately evaluate the MR EPT measurement process.

[0006] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0007] On one hand, embodiments of the present invention provide a phantom specifically for magnetic resonance dielectric property tomography, including a reference array unit, a dielectric property array unit, a single-layer support disk structure, and a spherical shell encapsulation structure;

[0008] The reference array unit includes multiple reference units. Each reference unit includes a first unit ball filled with a reference test solution and a corresponding first support stud. The first unit ball is mechanically connected to one end of the first support stud.

[0009] The dielectric property array unit includes multiple dielectric units. Each dielectric unit includes a second unit ball filled with a dielectric property test solution and a corresponding second support stud. The second unit ball is mechanically connected to one end of the second support stud. The dielectric property test solution is an electrolyte solution.

[0010] One side of the single-layer support disk structure is provided with a first threaded hole array, and the other side of the single-layer support disk structure is provided with a second threaded hole array. The first threaded hole array is used to install a reference array unit, and the threaded holes of the first threaded hole array are mechanically connected to the other end of the first support stud. The second threaded hole array is used to install a dielectric property array unit, and the threaded holes of the second threaded hole array are mechanically connected to the other end of the second support stud.

[0011] The spherical shell encapsulation structure includes two hemispherical shells that are detachably connected to form a sealed spherical structure. A single-layer support disk structure is installed inside the spherical structure, and the spherical structure is filled with phantom fluid.

[0012] In one embodiment, the reference test solution is a 3-4 mmol / L CuSO4 solution, and the dielectric property test solution is a 0.01-2.5 mol / L NaCl solution, with the concentration of the dielectric property test solution in each dielectric unit exhibiting a gradient distribution.

[0013] In one embodiment, the surface of the single-layer support disk structure is provided with uniformly and equidistantly distributed grid grooves.

[0014] In one embodiment, there are N reference array units, where N is an odd number greater than 1, and their corresponding threaded holes are distributed at the intersection of the grid grooves. There are M dielectric property array units, where M is an even number greater than 1, and their corresponding threaded holes are distributed at the center of the grid grooves.

[0015] In one embodiment, the two hemispherical shells are detachably connected by a flange structure or a threaded connection structure, and a circular groove is provided on the inner edge of the two hemispherical shells for fixing the single-layer support disk structure.

[0016] On the other hand, a method for preparing a phantom for magnetic resonance dielectric property tomography as described above is also provided, characterized in that the method includes the following steps:

[0017] Use software to draw a phantom model specifically for magnetic resonance dielectric property tomography.

[0018] Based on the model, a single-layer support disk structure, a spherical shell encapsulation structure containing two hemispherical shells, each first unit sphere, and each second unit sphere are constructed.

[0019] The reference test solution is filled into each first unit ball, and the first unit balls are connected one by one to the corresponding first support studs and then installed on one side of the single-layer support disk structure to form a reference array unit;

[0020] The dielectric property test solution is filled into each second unit ball, and the second unit balls are connected one by one to the corresponding second support studs and then installed on the other side of the single-layer support disk structure to form a dielectric property array unit.

[0021] A single-layer support disk structure is installed inside two hemispherical shells, and the two hemispherical shells are fixed together to form a spherical shell encapsulation structure.

[0022] The phantom fluid is filled into a spherical shell encapsulation structure to form a phantom specifically for magnetic resonance dielectric tomography.

[0023] In one embodiment, the steps of fabricating the single-layer support disk structure, the spherical shell encapsulation structure comprising two hemispherical shells, each first unit sphere, and each second unit sphere are fabricated using 3D printing technology or CNC precision machining technology.

[0024] In one embodiment, the 3D printing technology employs one of the following processes: SLA stereolithography, SLS selective laser sintering, and MJF multi-jet melting.

[0025] In one embodiment, the process of filling the reference test solution into the first unit sphere and the process of filling the dielectric property test solution into the second unit sphere employs the following solution filling method:

[0026] After drilling and injection, the injection hole is heat-sealed.

[0027] In one embodiment, the first unit ball and the first supporting stud are bonded together with epoxy resin AB glue, and the second unit ball and the second supporting stud are bonded together with epoxy resin AB glue.

[0028] One of the above technical solutions has the following advantages and beneficial effects:

[0029] The aforementioned phantom for magnetic resonance dielectric tomography (MRET) and its fabrication method simulate the dielectric properties of human tissue by designing independent array unit functional areas, namely dielectric property array units. Based on this, and combined with the basic functions of traditional system phantoms, a phantom with array units simulating the dielectric properties of human tissue can be fabricated, enabling accurate evaluation of the MRET measurement process. Furthermore, this technical solution offers low cost, high flexibility, and the ability to fabricate MRET phantoms with high accuracy, stability, and repeatability, allowing for performance evaluation of the same MRET technology on different magnetic resonance platforms. Attached Figure Description

[0030] Figure 1 This is a phantom model diagram for magnetic resonance dielectric property tomography in one embodiment;

[0031] Figure 2 This is a model diagram of a phantom array unit for magnetic resonance dielectric property tomography in one embodiment;

[0032] Figure 3 This is a schematic diagram of a single-layer supported disk structure model of a phantom for magnetic resonance dielectric property tomography in one embodiment.

[0033] Figure 4 This is a schematic diagram of a spherical shell encapsulation structure for a phantom specifically designed for magnetic resonance dielectric property tomography in one embodiment.

[0034] Figure 5 This is a physical image of a single-layer support disk structure for a phantom specifically designed for magnetic resonance dielectric property tomography in one embodiment.

[0035] Figure 6 This is a schematic flowchart of a method for preparing a phantom for magnetic resonance dielectric property tomography in one embodiment. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0038] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are implemented by those skilled in the art. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0039] This application provides a phantom specifically for magnetic resonance dielectric property tomography, such as Figure 1 As shown, it includes: a reference array unit 11, a dielectric property array unit 12, a single-layer support disk structure 13, and a spherical shell encapsulation structure 14.

[0040] The reference array cell includes multiple reference cells, such as Figure 2As shown in (a), each reference unit 21 includes a first unit ball 211 filled with a reference test solution and a corresponding first support stud 212, with the first unit ball 211 mechanically connected to one end of the first support stud 212.

[0041] The dielectric property array cell includes multiple dielectric cells, such as Figure 2 As shown in (b), each dielectric unit 22 includes a second unit ball 221 filled with a dielectric property test solution and a corresponding second support stud 222. The second unit ball 221 is mechanically connected to one end of the second support stud 222. The dielectric property test solution is an electrolyte solution.

[0042] It is understood that there can be multiple reference units 21 and dielectric units 22, and the size of each unit can be different according to the requirements. The solution in the reference unit 21 and dielectric unit 22 is used to imitate the liquid substance in human tissues and organs (such as the human brain). The first unit sphere 211 and the second unit sphere 221 are both hollow spheres with a certain thickness, which have good sealing and stability to ensure that the solution in the sphere does not seep out. Depending on the requirements of MR EPT evaluation, different types or ratios of solutions can be filled into the first unit sphere 211 and the second unit sphere 221, respectively. The dielectric property testing solution is an electrolyte solution with a concentration gradient. Different concentrations of electrolyte solutions have different dielectric properties. For example, in this embodiment, a CuSO4 solution of a certain concentration is used as the reference solution. CuSO4 solution is simple to prepare, low in cost, and can show a high signal shadow under T1 sequence even at low concentrations, facilitating image observation. Furthermore, the solution has low toxicity and stable properties at this concentration. The dielectric property testing solution is a NaCl solution with a concentration gradient. The higher the NaCl concentration, the greater the dielectric properties. NaCl solution is easy to prepare, non-toxic, highly safe, highly stable, and low in cost, making it an electrolyte solution with excellent overall performance. The reference array unit is used to test the basic performance parameters of MR EPT, and the dielectric property array unit is used to test the dielectric property parameters of MR EPT.

[0043] like Figure 3 As shown, one side of the single-layer support disk structure 31 is provided with a first threaded hole array 31, and the other side of the single-layer support disk structure is provided with a second threaded hole array 32. The first threaded hole array is used to install a reference array unit, and the threaded holes of the first threaded hole array are mechanically connected to the other end of the first support stud 212. The second threaded hole array is used to install a dielectric characteristic array unit, and the threaded holes of the second threaded hole array are mechanically connected to the other end of the second support stud 222.

[0044] It is understandable that the single-layer support disk structure is used to fix the reference array unit and the dielectric property array unit. The fixing method adopts a combination of threaded studs. The size of the threaded hole matches the stud size of the corresponding array unit, and its depth is determined by the length of the corresponding stud. It can pass through or not pass through the single-layer support disk body.

[0045] The spherical housing encapsulation structure 14 includes two hemispherical housings 141 and 142, as shown below. Figure 4 As shown, the two hemispherical shells are detachably connected to form a sealed spherical structure. A single-layer support disc structure is installed inside the spherical structure, which is filled with phantom fluid.

[0046] As can be understood, the spherical shell encapsulation structure serves as the outer shell of the entire magnetic resonance dielectric tomography phantom. It can be transparent or opaque, possesses excellent stability and sealing, and its size is similar to that of the human brain, making it compatible with most current head coils. The phantom fluid is a liquid that mimics human tissue fluid, and the type and amount of solution can be selected as needed.

[0047] In one embodiment, the reference test solution is a 3-4 mmol / L CuSO4 solution, and the dielectric property test solution is a 0.01 mol / L-2.5 mol / L NaCl solution, with the concentration of the dielectric property test solution in each dielectric unit exhibiting a gradient distribution.

[0048] It is understood that CuSO4 solution and NaCl solution are used to examine the baseline and dielectric properties of MR EPT in MR EPT evaluation, respectively. For the same type of array unit, solutions of the same type but different concentrations can be filled as needed. For example, in this embodiment, 3.21 mmol / L CuSO4 solution is filled in the 8 baseline array units, and the solution concentration in the 9 dielectric property array units is filled using a gradient distribution method. Figure 5 As shown, the NaCl solutions are 0.01, 0.1, 0.9, 1, 1.5, 2, 2.5, 3, and 3.5 mol / L, respectively. Since the higher the concentration of NaCl solution, the greater the dielectric properties, the dielectric properties of array units with different dielectric properties can be gradient-distributed, which is convenient for imaging comparison studies in MR EPT phantom testing.

[0049] In one embodiment, the surface of the single-layer support disk structure is provided with uniformly and equidistantly distributed grid grooves.

[0050] It is understandable that the grid groove is composed of groove lines in two mutually perpendicular directions, forming equidistant square grids. These square grids can be distributed on one or both sides of the single-layer support disc structure. The square grids are conducive to comparison and can well reflect the shape changes of the single-layer support disc structure before and after the test, further reflecting the degree of pressure on the phantom during the MR EPT test.

[0051] In one embodiment, there are N reference array units, where N is an odd number greater than 1, and their corresponding threaded holes are distributed at the intersection of the grid grooves. There are M dielectric property array units, where M is an even number greater than 1, and their corresponding threaded holes are distributed at the center of the grid grooves.

[0052] It is understandable that by setting the threaded holes of the reference array unit at the intersection of the grid grooves and the threaded holes of the dielectric property array unit at the center of the grid grooves, the reference array unit and the dielectric property array unit can be arranged using the grid features, so that the reference array unit and the dielectric property array unit are evenly distributed on the single-layer support disk structure, which is beneficial to improving image acquisition during the MR EPT test process.

[0053] In one embodiment, the two hemispherical shells are detachably connected by a flange structure or a threaded connection structure, and a circular groove is provided on the inner edge of the two hemispherical shells for fixing the single-layer support disc structure.

[0054] It is understood that flange structures are commonly used detachable connection structures for connecting container bodies and heads, bodies to bodies, pipes, and valves. They consist of a pair of flanges, several bolts, nuts, and a gasket, possessing strong sealing performance and good strength. In this embodiment, using flange structures to fix the two hemispherical shells of the spherical shell encapsulation structure effectively ensures the sealing performance of the spherical shell encapsulation structure and prevents leakage of the molding fluid inside the shell. A circular groove is provided around the inner edge of the hemispherical shell, with a radius equal to the radius of the single-layer support disc structure and a depth half the thickness of the single-layer support disc structure, effectively fixing the single-layer support disc structure. Threaded connection structures are detachable fixed connection structures, simple in structure, reliable in connection, and convenient to assemble and disassemble. Commonly used threaded connection structures include connections composed of bolts, studs, screws, and nuts.

[0055] This application provides a method for fabricating a phantom specifically for magnetic resonance dielectric property tomography, such as... Figure 6 As shown, it includes the following steps:

[0056] S1: Use software to draw a phantom model specifically for magnetic resonance dielectric property tomography.

[0057] S2: Based on the model, construct the single-layer support disk structure of the model, the spherical shell encapsulation structure containing two hemispherical shells, each first unit sphere and each second unit sphere;

[0058] S3: Fill each first unit ball with the reference test solution, connect each first unit ball to the corresponding first support stud, and install it onto one side of the single-layer support disk structure to form a reference array unit;

[0059] S4: Fill each second unit ball with dielectric property test solution, connect each second unit ball to the corresponding second support stud, and install it on the other side of the single-layer support disk structure to form a dielectric property array unit.

[0060] S5: Install the single-layer support disk structure inside the two hemispherical shells, and fix the two hemispherical shells together to form a spherical shell encapsulation structure;

[0061] S6: Fill the phantom fluid into the spherical shell encapsulation structure to form a phantom specifically for magnetic resonance dielectric tomography.

[0062] It is understood that the drawing software used in step S1 can be SolidWorks, AutoCAD, 3D Max, or other drafting software.

[0063] It is understandable that in steps S3 and S4, the solution must fill the unit sphere. Filling the entire sphere with liquid can make the array unit imaging within the phantom uniform, which is convenient for imaging positioning, geometric measurement, and subsequent evaluation of the distortion and feasibility of sphere MR imaging.

[0064] It is understandable that in steps S3 and S4, there is a one-to-one correspondence between the unit ball and the supporting stud, and there is also a one-to-one correspondence between the supporting stud of the combined array unit and the screw hole of the single-layer supporting disk structure.

[0065] It is understood that in step S5, both hemispherical shells are designed with grooves. These grooves are specifically designed to hold the single-layer support disc structure. Therefore, the radius of the groove is the same as the radius of the single-layer support disc structure, and the depth of the groove is half that of the single-layer support disc structure. This can effectively fix the single-layer support disc structure and ensure the stability of the entire model.

[0066] It is understandable that in step S6, when filling the phantom fluid into the spherical shell encapsulation structure, the method of injection followed by heat sealing can be adopted.

[0067] In one embodiment, the steps of fabricating the single-layer support disk structure, the spherical shell encapsulation structure comprising two hemispherical shells, each first unit sphere, and each second unit sphere are fabricated using 3D printing technology or CNC precision machining technology.

[0068] As can be understood, 3D printing technology is based on digital model files and uses powdered metal or plastic and other bondable materials to construct modules by printing layer by layer. CNC precision machining technology refers to computer-controlled precision machining technology, which uses digital control technology and CNC machine tools to create parts. Both 3D printing and CNC precision machining technologies are relatively mature modern processing technologies with excellent manufacturing precision, which can ensure the accuracy and stability of the prepared models.

[0069] In one embodiment, the 3D printing technology employs one of the following processes: SLA stereolithography, SLS selective laser sintering, and MJF multi-jet melting.

[0070] It is understandable that SLA stereolithography, SLS selective laser sintering, and MJF multi-jet melting are all mature 3D printing technologies that can achieve high-precision printing of model parts and ensure the accuracy and stability of the model preparation process.

[0071] In one embodiment, the process of filling the reference test solution into the first unit ball and the dielectric property test solution into the second unit ball uses a solution filling method of: injecting through a hole and then heat-sealing the injection hole.

[0072] It is understandable that a syringe is used to fill the hollow unit spheres of the array with solution. After filling, the material at the injection port is heated to make it reach a viscous flow state and then pressure is applied to seal it. Alternatively, heat sealing tape can be used to seal the injection hole. This heat sealing method can have good sealing and stability, ensuring that the solution inside the unit sphere does not overflow and can ensure that the overall morphology of the device itself is not affected to the greatest extent.

[0073] In one embodiment, the first unit ball and the first supporting stud are bonded together with epoxy resin AB glue, and the second unit ball and the second supporting stud are bonded together with epoxy resin AB glue.

[0074] It is understandable that epoxy resin AB adhesive is a two-component high-temperature resistant adhesive based on epoxy resin. It can be cured at low or room temperature, has a fast curing speed, and after curing, it has high bonding strength, good hardness, and a certain degree of toughness. The cured product has good acid and alkali resistance, and excellent moisture-proof, waterproof, oil-proof, and dust-proof properties. It is resistant to humid heat and atmospheric aging, and has good electrical and physical properties such as insulation, compressive strength, and high bonding strength. It can well ensure the stability of the reference test unit and dielectric property test unit.

[0075] It should be understood that, although Figure 6 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order in which these steps are executed, and they can be performed in other orders. Figure 6 At least some of the steps in the process may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least some of the sub-steps or stages of other steps.

[0076] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0077] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A phantom specifically designed for magnetic resonance dielectric property tomography, characterized in that, It includes a reference array unit, a dielectric property array unit, a single-layer support disk structure, and a spherical shell packaging structure; The reference array unit includes multiple reference units, each of which includes a first unit ball filled with a reference test solution and a corresponding first support stud, wherein the first unit ball is mechanically connected to one end of the first support stud. The dielectric property array unit includes multiple dielectric units. Each dielectric unit includes a second unit ball filled with a dielectric property test solution and a corresponding second support stud. The second unit ball is mechanically connected to one end of the second support stud. The dielectric property test solution is an electrolyte solution. One side of the single-layer support disk structure is provided with a first threaded hole array, and the other side of the single-layer support disk structure is provided with a second threaded hole array. The first threaded hole array is used to install the reference array unit, and the threaded holes of the first threaded hole array are mechanically connected to the other end of the first support stud. The second threaded hole array is used to install the dielectric property array unit, and the threaded holes of the second threaded hole array are mechanically connected to the other end of the second support stud. The spherical shell encapsulation structure includes two hemispherical shells that are detachably connected to form a sealed spherical structure. The single-layer support disk structure is installed inside the spherical structure, and the spherical structure is filled with a phantom fluid.

2. The phantom for magnetic resonance dielectric property tomography according to claim 1, characterized in that, The reference test solution is a 3-4 mmol / L CuSO4 solution, and the dielectric property test solution is a 0.01-2.5 mol / L NaCl solution. The concentration of the dielectric property test solution in each dielectric unit is distributed in a gradient.

3. The phantom for magnetic resonance dielectric property tomography according to claim 1, characterized in that, The surface of the single-layer support disc structure is provided with uniformly and equidistantly distributed grid grooves.

4. The phantom for magnetic resonance dielectric property tomography according to claim 3, characterized in that, The reference array unit has N units, where N is an odd number greater than 1, and its corresponding threaded holes are distributed at the intersection of the grid grooves. The dielectric property array unit has M units, where M is an even number greater than 1, and its corresponding threaded holes are distributed at the center of the grid grooves.

5. The phantom for magnetic resonance dielectric property tomography according to claim 4, characterized in that, The two hemispherical shells are detachably connected by a flange structure or a threaded connection structure. A circular groove is provided on the inner edge of the two hemispherical shells to fix the single-layer support disc structure.

6. A method for preparing a phantom for magnetic resonance dielectric property tomography as described in any one of claims 1-5, characterized in that, The method includes the following steps: The phantom model for magnetic resonance dielectric property tomography was drawn using software. Based on the phantom model, a single-layer supporting disk structure, a spherical shell encapsulation structure containing two hemispherical shells, each first unit sphere, and each second unit sphere are fabricated for the phantom model. The reference test solution is filled into each of the first unit balls, and the first unit balls are connected one by one to the corresponding first support studs and then installed on one side of the single-layer support disk structure to form a reference array unit; The dielectric property test solution is filled into each of the second unit balls, and the second unit balls are connected one by one to the corresponding second support studs and then installed on the other side of the single-layer support disk structure to form a dielectric property array unit. The single-layer support disk structure is installed inside the two hemispherical shells, and the two hemispherical shells are fixed together to form a spherical shell encapsulation structure. The phantom fluid is filled into a spherical shell encapsulation structure to form a phantom specifically for magnetic resonance dielectric tomography.

7. The method for preparing a phantom for magnetic resonance dielectric property tomography according to claim 6, characterized in that, The manufacturing process of the single-layer support disk structure, the spherical shell encapsulation structure containing two hemispherical shells, each first unit sphere and each second unit sphere can be carried out using 3D printing technology or CNC precision machining technology.

8. The method for preparing a phantom for magnetic resonance dielectric property tomography according to claim 7, characterized in that, The 3D printing technology mentioned uses one of the following processes: SLA stereolithography, SLS selective laser sintering, and MJF multi-jet melting.

9. The method for preparing a phantom for magnetic resonance dielectric property tomography according to claim 6, characterized in that, The process of filling the reference test solution into the first unit sphere and the process of filling the dielectric property test solution into the second unit sphere employs the following solution filling method: After drilling and injection, the injection hole is heat-sealed.

10. The method for preparing a phantom for magnetic resonance dielectric property tomography according to claim 6, characterized in that, The first unit ball and the first supporting stud are bonded together with epoxy resin AB glue, and the second unit ball and the second supporting stud are bonded together with epoxy resin AB glue.

Images