Multi-density polymer composite die body for CT (Computed Tomography) detection and preparation method of multi-density polymer composite die body

Abstract

The invention provides a polymer composite die body for CT (Computed Tomography) detection, which comprises a die body frame, at least one replaceable body module is arranged on the die body frame, and the body module is prepared by compounding at least two materials of polytetrafluoroethylene (PTFE), polypropylene (PP), polyurethane (PU), polyvinyl chloride (PVC) and polyethylene (PE), so that the CT values of different body modules can cover the full range of-1000HU to + 1200HU. The device is used for simulating the density characteristics of different tissues and organs of a human body and the specific density of specific diseases. The invention has the beneficial effects that the replaceable body module and the main water mold body are arranged in the same mold body, the structure is simple, the operation is convenient and fast, and the cost is low; through a five-dimensional polymer compound system, the body module capable of simulating density characteristics of different tissues and organs of a human body and specific density of specific diseases is prepared, and full-density coverage from-1000HU to + 1200HU is realized, so that the accuracy and efficiency of quality control and performance evaluation of CT equipment are remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of medical device technology, specifically relating to a multi-density polymer composite phantom for CT detection. Background Technology

[0002] International research on CT performance testing is constantly evolving. The United States, the United Kingdom, the European Union, and Japan have all published standard measurement methods. As an international standard, the International Electrotechnical Commission (IEC) has also published IEC 1223-2-6, which is adopted by many countries. my country has also long ago formulated national standards for CT testing, the latest of which is the "Quality Assurance Testing Specification for X-ray Computed Tomography Devices GB / T17589-2011". This standard clearly specifies the CT value, noise, and uniformity of water, and these are mandatory testing items for CT devices as stipulated by national regulations.

[0003] The CT detection phantoms commonly used in the market are mainly divided into two categories: water phantoms and solid phantoms.

[0004] A water phantom is a phantom that uses water as a medium and has a CT value of 0 HU (Hounsfield Unit). It is mainly used to calibrate the baseline values ​​of equipment and evaluate image uniformity. However, traditional water phantoms can only simulate the density of water (0 HU) and cannot meet the simulation requirements of various tissue densities (such as bone, muscle, fat, etc.). Furthermore, traditional materials (such as acrylic resin) are prone to cracking and damage under long-term exposure to X-rays, which affects the detection results.

[0005] For example, Chinese patent CN202410728061.3 discloses a CT water phantom and its preparation method, including a retaining ring forming a closed loop, a cover connected to an opening on one side of the retaining ring, and a cover installed at an opening on the other side; the inner cavity of the retaining ring is provided with a dividing component, which divides the inner cavity of the retaining ring into multiple nested cavities, wherein the cross-section of each cavity in the multiple cavities is a similar graphic structure, and the top of each cavity has a connecting channel with the adjacent cavity above it. The use of a multi-layered stacked sleeve allows for adjustment of the size of the water phantom by the amount of water, and the shapes of each water phantom are similar cylindrical structures, facilitating comparison work with the same group.

[0006] Phantoms refer to containers filled with materials of equivalent density to human tissue, used for more comprehensive performance testing. However, limitations in material technology result in high manufacturing and maintenance costs, with imported phantoms costing approximately 200,000-300,000 RMB per set, restricting their widespread application in small and medium-sized medical institutions. Furthermore, existing technologies struggle to provide precise, disease-specific density models for different CT scan sequences (such as low-dose lung nodule screening, enhanced CT, and CT angiography), leading to insufficient accuracy in diagnostic verification.

[0007] For example, Chinese patent CN201910407919.5 discloses a CT performance testing phantom and its testing method for CT automatic tube current modulation mode. The CT performance testing phantom, with polymethyl methacrylate as its main material, includes: a CT value detection module, a high contrast resolution detection module, a low contrast resolution detection module, and field uniformity and noise detection modules; it can be used to measure the uniformity and noise of all layers under tube current modulation mode. This solves the problem that current image quality testing phantoms are not suitable for scanning CT images in automatic tube current modulation mode. It can automatically analyze the image quality evaluation parameters (CT value linearity, noise, uniformity, high contrast resolution, low contrast resolution, texture features, etc.) generated by the automatic tube current modulation scanning sequence, realizing the image quality performance evaluation of the new CT technology—automatic tube current modulation technology. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention aims to provide a polymer composite phantom for CT detection that is simple in structure, easy to operate, low in cost, and can accurately simulate the density characteristics of different human tissues and organs, as well as the specific density of specific diseases.

[0009] Another object of the present invention is to provide a method for preparing a multi-density polymer composite phantom for CT detection.

[0010] The objective of this invention is achieved through the following technical solution: a polymer composite phantom for CT detection, comprising a phantom frame, wherein at least one replaceable body module is disposed on the phantom frame, the body module being made of at least two materials selected from polytetrafluoroethylene (PTFE), polypropylene (PP), polyurethane (PU), polyvinyl chloride (PVC) and polyethylene (PE), so that the CT values ​​of different body modules can cover the full range from -1000HU to +1200HU, for simulating the density characteristics of different tissues and organs of the human body, as well as the specific density of specific diseases.

[0011] A volumetric module capable of simulating the density characteristics of different human tissues and organs was prepared using a five-dimensional polymer compound system. The replaceable volumetric module enables precise and stable simulation of different tissue densities within the same phantom. By precisely controlling parameters such as the mixing ratio, crosslinking density, and porosity of the polymer materials in the volumetric module's compound formulation, specific density CT values ​​can be obtained, achieving full density coverage from -1000 HU to +1200 HU, supporting accurate simulation of CT sequences for various diseases. The CT values ​​of the volumetric module are stable within ±10 HU, thereby significantly improving the accuracy and efficiency of CT equipment quality control and performance evaluation.

[0012] Based on the above scheme, the body module is made of at least two of the following polymer materials: 60-80% polytetrafluoroethylene (PTFE), 40-50% polypropylene (PP), 30-70% polyurethane (PU), 20-60% polyvinyl chloride (PVC) or 10-30% polyethylene (PE).

[0013] 60-80% polytetrafluoroethylene (PTFE) can be used to simulate bone cortex, 40-50% polypropylene (PP) can be used to simulate soft tissue substrate, 30-70% polyurethane (PU) can be used to simulate muscle / fat, 20-60% polyvinyl chloride (PVC) can be used to simulate vascular reinforcement, and 10-30% polyethylene (PE) can be used as filler material to prepare body modules that simulate the density characteristics of different tissues and organs in the human body.

[0014] Based on the above scheme, the compound formula of the body module is PTFE 40% + PU 60%, PP 50% + PVC 30% + PE 20%, PTFE 80% + PU 20%, PU 70% + PE 30%, PP 40% + PVC 60% or PU 50% + PE 50%.

[0015] PTFE 40% + PU 60% can be used to simulate low-dose plain scan for lung nodule screening; PP 50% + PVC 30% + PE 20% can be used to simulate phase III enhanced liver cancer diagnosis; PTFE 80% + PU 20% can be used to simulate high-resolution scan for bone metastasis detection; PU 70% + PE 30% can be used for perfusion imaging for stroke assessment; PP 40% + PVC 60% can be used to simulate CTA angiography for coronary artery stenosis; and PU 50% + PE 50% can be used to simulate low-energy X-ray for breast cancer screening. These methods allow for the fabrication of volumetric modules with specific densities that mimic specific diseases.

[0016] Based on the above scheme, the phantom frame is also provided with at least one main water phantom for simulating water density. The main water phantom is a multi-layer nested sleeve structure, and the detection volume can be infinitely changed by adjusting the water injection volume.

[0017] By setting replaceable body modules and main water model in the same model, the versatility of the model is enhanced and replacement costs are reduced.

[0018] Based on the above scheme, the main water model body includes an outer shell and at least one layer of sleeve disposed in the inner cavity of the outer shell. The cross-section of the outer shell and each layer of sleeve is a concentric cylinder. Each layer of sleeve divides the inner cavity into a multi-layer nested sleeve structure. Each layer of sleeve is connected to the other through a connecting channel at the bottom. By injecting or discharging water into each layer of sleeve, the volume of each layer of sleeve can be infinitely changed, while maintaining the geometric similarity between each layer of sleeve.

[0019] The main water model adopts a multi-layer nested sleeve structure design, which can achieve stepless change of the detection volume by adjusting the water injection volume, maintaining the geometric similarity of each layer of sleeve (cylindricity error <0.1mm) and avoiding repeated calibration.

[0020] Based on the above scheme, the sleeve is equipped with an adjustment knob for manually adjusting the sleeve volume.

[0021] Based on the above scheme, the outer shell is made of polyvinyl chloride (PVC) and the sleeve is made of polypropylene (PP).

[0022] Based on the above scheme, the sleeve is equipped with a scale indicator and a quick-sealing interface.

[0023] Modularly designed scale indicators and quick-sealing interfaces improve operational efficiency.

[0024] Furthermore, the quick-sealing interface is made of polymethyl methacrylate (PMMA) material.

[0025] The quick-sealing interface is made of medical-grade PMMA material, ensuring sealing and durability, and facilitating on-site testing, carrying, and replacement.

[0026] Based on the above scheme, the phantom frame is equipped with an air storage bladder for temperature compensation.

[0027] The air bladder, which serves as a temperature compensation device, is connected to the phantom frame to reduce measurement errors caused by temperature effects.

[0028] Another objective of this invention is achieved through the following technical solution: a method for preparing a polymer composite phantom for CT detection, comprising the following steps: 1) The selected polymer material is used as the matrix material and is initially dried to obtain a dried matrix body; 2) The dried substrate is fed into a mixing tank in proportion and premixed to obtain material A; 3) Weigh 0.1-0.8 parts of compatibilizer and feed it together with material A into a high-speed mixer for mixing; 4) Vacuum degas the mixed material A; 5) The vacuum-degassed material A is fed into a twin-screw extruder for physical blending and extrusion, and then ring-cut in water to obtain material B; 6) After drying material B, use a vacuum casting process to melt and blend material B into the injection mold; 7) The molten material B in the injection mold is heated and pressurized in a stepwise manner to achieve incremental gradient solidification and obtain a solidified density body; 8) Wrap the cured density material with PE stretch film to maintain the cured state, and then place it in a constant temperature and humidity environment to cool and stabilize it; 9) Perform a CT value test on the cooled density body. If the CT value is stable within ±10HU, it is considered qualified. 10) Cut the qualified density body into standard-sized body modules.

[0029] Further steps include the following: 1) The selected polymer material is used as the matrix material and is initially dried to obtain a dry matrix with a moisture content of less than 5%; 2) The dried substrate is fed into a mixing tank in proportion and premixed for 30 minutes at 25±2℃ / normal pressure to obtain material A; 3) Weigh 0.1-0.8 parts of compatibilizer and feed it together with material A into a high-speed mixer and mix at a rate of 150 R / min; 4) Degas the mixed material A under vacuum at 60±5℃ / -0.08MPa for 45 minutes; 5) The vacuum-degassed material is fed into a twin-screw extruder for physical blending and extrusion. During this process, the temperature range of the extruder must be controlled at 150~220℃ and the temperature range of the water ring cutting must be controlled at 80~90℃ to obtain material B. 6) After drying material B for 30 minutes, use vacuum casting process to melt and blend material B into the injection mold. During this process, the blending temperature range needs to be controlled between 150 and 220°C. 7) The molten material B in the injection mold is kept at 80℃ / 0.5MPa for 60min, at 100℃ / 1MPa for 60min, and at 120℃ / 2MPa for 60min, for a total of 180min in an incremental gradient curing process to obtain the cured density body. 8) Wrap the density material with PE stretch film, continue to cure at 25℃ / normal pressure for 720 minutes, and then place it in a constant temperature and humidity environment to cool and stabilize for 36 hours; 9) Perform a CT value test on the cooled density body. If the CT value is stable within ±10HU, it is considered qualified. 10) Cut the qualified density body into standard-sized body modules.

[0030] Based on the above scheme, the injection mold is prepared through the following steps: a) After passing the material B obtained in step 5 through a sieve, send it back into the air shower dryer for drying to obtain material C; b) Mix 10% (w / w) of material C, 85% (w / w) of PMMA, and 5% (w / w) of hydroxyapatite nanoparticles, and then feed them into an injection molding machine for molding. c) The injection-molded material C is heated and pressurized in a stepwise manner to achieve incremental gradient curing, thereby obtaining a cured injection mold. d) Wrap the cured injection mold with PE stretch film, continue to maintain the cured state, and then place it in a constant temperature and humidity environment to cool, thus obtaining the injection mold.

[0031] Furthermore, the injection mold is prepared by the following steps: a) After passing the material B obtained in step 5 through a sieve, it is sent back into the air shower dryer for 30 minutes to dry and obtain material C. b) Mix 10% (w / w) of material C, 85% (w / w) of PMMA and 5% (w / w) of hydroxyapatite nanoparticles at a rate of 150 R / min and then feed them into an injection molding machine for molding. During this process, the equipment temperature range needs to be controlled between 150 and 220°C. c) The injection-molded material C is kept at 80℃ / 0.5MPa for 60min, at 100℃ / 1MPa for 60min, and at 120℃ / 2MPa for 60min, for a total of 180min in an incremental gradient curing process to obtain the cured injection mold. d) The injection mold is wrapped with PE stretch film and cured, and then cured at 25℃ / normal pressure for 720 min. After that, it is placed in a constant temperature and humidity environment to cool and stabilize for 48 hours to obtain the injection mold.

[0032] The preparation method of the body module in this invention includes the following steps: 1. Material selection and proportioning: Based on the density characteristics of the target tissues and organs and the compatibility ratio of polymeric material properties, two or more materials are selected from polypropylene (PP), polyethylene (PE), polyurethane (PU), polyvinyl chloride (PVC), and polytetrafluoroethylene (PTFE) for composite composition, and their proportions are determined. The structural stability, cost, simulated soft tissue, shell protection, and simulated bone of each material are analyzed.

[0033] 2. Composite process: Selected polymer materials are composite molded using processes such as melt blending, extrusion injection molding, or 3D printing to create bulk modules with specific density characteristics.

[0034] 3. Density calibration: The module prepared above is scanned on a standard CT device to measure its CT value, and compared with the CT value of the specific density of the target tissue or organ or a specific disease. The material ratio is adjusted until the target CT value range is reached.

[0035] 4. Stability Test: Long-term stability testing was conducted on the calibrated module to ensure that its CT value remained stable during the service life, with fluctuations controlled within ±2HU.

[0036] The beneficial effects of this invention are: This invention features replaceable body modules and a main water phantom within the same phantom, resulting in a simple structure, convenient operation, and low cost. Through a five-dimensional polymer composite system, body modules capable of simulating the density characteristics of different human tissues and organs, as well as the specific densities of specific diseases, are prepared, achieving full density coverage from -1000HU to +1200HU. This significantly improves the accuracy and efficiency of CT equipment quality control and performance evaluation. Attached Figure Description

[0037] Figure 1 A schematic diagram of the structure of this invention; Figure 2 Schematic diagram of the main water mold sleeve of this invention; Figure 3 Performance analysis diagram of the polymer materials PP, PE, PU, ​​PVC and PTFE in the compound formulation of this invention; Figure 4 A process flow diagram of the preparation method of this invention; Figure 1 Explanation of the award number: 1—Phantom frame; 2 — Body Module; 3——Main water phantom; 31—Outer shell; 32—Outer sleeve; 33—Middle layer casing; 34—Inner sleeve; 35 — Connecting channel; 36 — Quick-sealing interface. Detailed Implementation

[0038] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0039] Example 1 like Figure 1-3 As shown, a polymer composite phantom for CT detection includes a phantom frame 1, on which ten replaceable body modules 2, two main water phantoms 3 for simulating water density, and an air reservoir for temperature compensation are provided. The body module 2 is made of at least two of the following materials: polytetrafluoroethylene (PTFE), polypropylene (PP), polyurethane (PU), polyvinyl chloride (PVC), and polyethylene (PE), so that the CT values ​​of different body modules 2 can cover the full range from -1000HU to +1200HU, which is used to simulate the density characteristics of different tissues and organs in the human body, as well as the specific density of specific diseases. The main water model body 3 includes an outer shell 31 and outer, middle, and inner sleeves 32, 33, and 34 disposed in the inner cavity of the outer shell 31. The cross-sections of the outer shell 31 and the outer, middle, and inner sleeves 32, 33, and 34 are all concentric cylinders. The outer, middle, and inner sleeves 32, 33, and 34 divide the inner cavity into a multi-layer nested sleeve structure. The outer, middle, and inner sleeves 32, 33, and 34 are connected by a connecting channel 35 at the bottom. The outer, middle, and inner sleeves 32, 33, and 34 are equipped with adjustment knobs, scale indicators, and quick-sealing interfaces 36 for manually adjusting the sleeve volume. By injecting or draining water into the outer, middle, and inner sleeves 32, 33, and 34 respectively, the volume of the outer, middle, and inner sleeves 32, 33, and 34 can be infinitely changed while maintaining the geometric similarity between the outer, middle, and inner sleeves 32, 33, and 34.

[0040] Based on the above scheme, the outer shell 31 is made of polyvinyl chloride (PVC), the outer, middle and inner sleeves 32, 33 and 34 are made of polypropylene (PP), and the quick-sealing interface 36 is made of polymethyl methacrylate (PMMA).

[0041] The specific structural parameters of Example 1 are shown in Table 1: .

[0042] By systematically comparing five polymer materials—polypropylene (PP), polyethylene (PE), polyurethane (PU), polyvinyl chloride (PVC), and polytetrafluoroethylene (PTFE)—a five-dimensional composite system was constructed. The optimized scheme of the polymer composite system for the main water phantom 3 and the body module 2 is as follows (Table 2): .

[0043] To address the different CT examination needs for various diseases and the specific densitometer configurations required for each disease, several types of dedicated densitometer modules have been designed. Examples of some typical formulations are shown in Table 3. .

[0044] Based on the compounding ratio and formulation, module 3 was prepared using a gradient curing process. The key process parameters are as follows (Table 4): .

[0045] Module 2 needs to pass performance testing and verification. Its key performance indicators are as follows (Table 5): .

[0046] Example 2 A method for preparing a polymeric composite phantom for low-dose plain CT screening of pulmonary nodules, comprising the following steps: 1) Using the PTFE 40% / PU 60% composite system from the five-dimensional compound system as the matrix material, the ash was removed visually, and then sieved through a 600-mesh sieve. After drying and UV sterilization, an initial drying was performed to obtain a dried matrix body with a moisture content of less than 5%. 2) The dried substrate is fed into a mixing tank in a ratio of 40:60 by mass, and premixed for 30 minutes at 25±2℃ / normal pressure to obtain material A; 3) Weigh 0.1-0.8 parts of compatibilizer and feed it together with material A into a high-speed mixer and mix at a rate of 150 R / min; 4) Degas the mixed material A under vacuum at 60±5℃ / -0.08MPa for 45 minutes; 5) The vacuum-degassed material is fed into a twin-screw extruder for physical blending and extrusion. During this process, the temperature range of the extruder must be controlled at 150~220℃ and the temperature range of the water ring cutting must be controlled at 80~90℃ to obtain material B. 6) After drying material B for 30 minutes, use vacuum casting process to melt and blend material B into the injection mold. During this process, the blending temperature range needs to be controlled between 150 and 220°C. 7) The molten material B in the injection mold is kept at 80℃ / 0.5MPa for 60min, at 100℃ / 1MPa for 60min, and at 120℃ / 2MPa for 60min, for a total of 180min in an incremental gradient curing process to obtain the cured density body. 8) Wrap the density material with PE stretch film, continue to cure at 25℃ / normal pressure for 720 minutes, and then place it in a constant temperature and humidity environment to cool and stabilize for 36 hours; 9) Perform a CT value test on the cooled density body. If the CT value is stable within ±10HU, it is considered qualified. 10) Cut the qualified density body into standard-sized body modules 2 and integrate them into the mold frame 1.

[0047] Based on the above scheme, the injection mold is prepared through the following steps: a) After passing the material B obtained in step 5 through a sieve, it is sent back into the air shower dryer for 30 minutes to dry and obtain material C. b) Mix 10% (w / w) of material C, 85% (w / w) of PMMA and 5% (w / w) of hydroxyapatite nanoparticles at a rate of 150 R / min and then feed them into an injection molding machine for molding. During this process, the equipment temperature range needs to be controlled between 150 and 220°C. c) The injection-molded material C is kept at 80℃ / 0.5MPa for 60min, at 100℃ / 1MPa for 60min, and at 120℃ / 2MPa for 60min, for a total of 180min in an incremental gradient curing process to obtain the cured injection mold. d) The injection mold is wrapped with PE stretch film and cured, and then cured at 25℃ / normal pressure for 720 min. After that, it is placed in a constant temperature and humidity environment to cool and stabilize for 48 hours to obtain the injection mold.

[0048] The phantom frame of Example 2 was sent to CT scan. Under low-dose scanning conditions of 120kVp / 50mAs, it achieved lung parenchyma simulation of -950 to -700 HU, which can detect nodules larger than 3mm and reduce the false positive rate to 8.5%.

[0049] Example 3 A method for preparing a polymeric composite phantom for three-phase enhanced CT detection in the diagnosis of liver cancer, comprising the following steps: 1) Using a polymer material from the five-dimensional compound system consisting of 50% PP, 30% PVC, and 20% PE as the matrix material, the ash was removed visually, and then sieved through a 600-mesh screen. After drying and UV sterilization, an initial drying process was performed to obtain a dried matrix with a moisture content of less than 5%. 2) The dried substrate is fed into a mixing tank in a ratio of 50:30:20 by mass, and premixed for 30 minutes at 25±2℃ / normal pressure to obtain material A; 3) Weigh 0.1-0.8 parts of compatibilizer and feed it together with material A into a high-speed mixer and mix at a rate of 150 R / min; 4) Degas the mixed material A under vacuum at 60±5℃ / -0.08MPa for 45 minutes; 5) The vacuum-degassed material is fed into a twin-screw extruder for physical blending and extrusion. During this process, the temperature range of the extruder must be controlled at 150~220℃ and the temperature range of the water ring cutting must be controlled at 80~90℃ to obtain material B. 6) After drying material B for 30 minutes, use vacuum casting process to melt and blend material B into the injection mold. During this process, the blending temperature range needs to be controlled between 150 and 220°C. 7) The molten material B in the injection mold is kept at 80℃ / 0.5MPa for 60min, at 100℃ / 1MPa for 60min, and at 120℃ / 2MPa for 60min, for a total of 180min in an incremental gradient curing process to obtain the cured density body. 8) Wrap the density material with PE stretch film, continue to cure at 25℃ / normal pressure for 720 minutes, and then place it in a constant temperature and humidity environment to cool and stabilize for 36 hours; 9) Perform a CT value test on the cooled density body. If the CT value is stable within ±10HU, it is considered qualified. 10) Cut the qualified density body into standard-sized body modules 2 and integrate them into the mold frame 1.

[0050] Based on the above scheme, the injection mold is prepared through the following steps: a) After passing the material B obtained in step 5 through a sieve, it is sent back into the air shower dryer for 30 minutes to dry and obtain material C. b) Mix 10% (w / w) of material C, 85% (w / w) of PMMA and 5% (w / w) of hydroxyapatite nanoparticles at a rate of 150 R / min and then feed them into an injection molding machine for molding. During this process, the equipment temperature range needs to be controlled between 150 and 220°C. c) The injection-molded material C is kept at 80℃ / 0.5MPa for 60min, at 100℃ / 1MPa for 60min, and at 120℃ / 2MPa for 60min, for a total of 180min in an incremental gradient curing process to obtain the cured injection mold. d) The injection mold is wrapped with PE stretch film and cured, and then cured at 25℃ / normal pressure for 720 min. After that, it is placed in a constant temperature and humidity environment to cool and stabilize for 48 hours to obtain the injection mold.

[0051] The phantom frame of Example 3 was sent to CT for detection. Under the enhanced scanning conditions of 120kVp / 100mAs, it achieved +95±15 HU in the arterial phase, +75±15 HU in the portal venous phase, and +60±15 HU in the delayed phase. The enhanced detection rate in the arterial phase was increased to 92%, which can accurately reflect the "fast in and fast out" characteristics of liver cancer lesions in enhanced scanning.

[0052] Example 4 A method for preparing a polymeric composite phantom for high-resolution CT detection of bone metastases, comprising the following steps: 1) Using the PTFE 80% / PU 20% composite system from the five-dimensional compound system as the matrix material, the ash was removed visually, and then sieved through a 600-mesh sieve. After drying and UV sterilization, an initial drying was performed to obtain a dried matrix body with a moisture content of less than 5%. 2) The dried substrate is fed into a mixing tank in a ratio of 80:20 by mass, and premixed for 30 minutes at 25±2℃ / normal pressure to obtain material A; 3) Weigh 0.1-0.8 parts of compatibilizer and feed it together with material A into a high-speed mixer and mix at a rate of 150 R / min; 4) Degas the mixed material A under vacuum at 60±5℃ / -0.08MPa for 45 minutes; 5) The vacuum-degassed material is fed into a twin-screw extruder for physical blending and extrusion. During this process, the temperature range of the extruder must be controlled at 150~220℃ and the temperature range of the water ring cutting must be controlled at 80~90℃ to obtain material B. 6) After drying material B for 30 minutes, use vacuum casting process to melt and blend material B into the injection mold. During this process, the blending temperature range needs to be controlled between 150 and 220°C. 7) The molten material B in the injection mold is kept at 80℃ / 0.5MPa for 60min, at 100℃ / 1MPa for 60min, and at 120℃ / 2MPa for 60min, for a total of 180min in an incremental gradient curing process to obtain the cured density body. 8) Wrap the density material with PE stretch film, continue to cure at 25℃ / normal pressure for 720 minutes, and then place it in a constant temperature and humidity environment to cool and stabilize for 36 hours; 9) Perform a CT value test on the cooled density body. If the CT value is stable within ±10HU, it is considered qualified. 10) Cut the qualified density body into standard-sized body modules 2 and integrate them into the mold frame 1.

[0053] Based on the above scheme, the injection mold is prepared through the following steps: a) After passing the material B obtained in step 5 through a sieve, it is sent back into the air shower dryer for 30 minutes to dry and obtain material C. b) Mix 10% (w / w) of material C, 85% (w / w) of PMMA and 5% (w / w) of hydroxyapatite nanoparticles at a rate of 150 R / min and then feed them into an injection molding machine for molding. During this process, the equipment temperature range needs to be controlled between 150 and 220°C. c) The injection-molded material C is kept at 80℃ / 0.5MPa for 60min, at 100℃ / 1MPa for 60min, and at 120℃ / 2MPa for 60min, for a total of 180min in an incremental gradient curing process to obtain the cured injection mold. d) The injection mold is wrapped with PE stretch film and cured, and then cured at 25℃ / normal pressure for 720 min. After that, it is placed in a constant temperature and humidity environment to cool and stabilize for 48 hours to obtain the injection mold.

[0054] The phantom frame of Example 4 was sent to CT for detection. Under high-resolution scanning conditions of 120kVp / 100mAs, it achieved CT value gradient coverage of +250 ~ +1000 HU, which can clearly distinguish between cortical bone and cancellous bone, providing a reliable benchmark for the detection and evaluation of bone metastases.

[0055] Example 5 A method for preparing a polymeric composite phantom for perfusion imaging CT detection in stroke assessment, comprising the following steps: 1) Using the 70% PU / 30% PE composite system from the five-dimensional compound system as the matrix material, the ash was removed visually, and then sieved through a 600-mesh screen. After drying and UV sterilization, an initial drying was performed to obtain a dried matrix body with a moisture content of less than 5%. 2) The dried substrate is fed into a mixing tank in a ratio of 70:30 by mass, and premixed for 30 minutes at 25±2℃ / normal pressure to obtain material A; 3) Weigh 0.1-0.8 parts of compatibilizer and feed it together with material A into a high-speed mixer and mix at a rate of 150 R / min; 4) Degas the mixed material A under vacuum at 60±5℃ / -0.08MPa for 45 minutes; 5) The vacuum-degassed material is fed into a twin-screw extruder for physical blending and extrusion. During this process, the temperature range of the extruder must be controlled at 150~220℃ and the temperature range of the water ring cutting must be controlled at 80~90℃ to obtain material B. 6) After drying material B for 30 minutes, use vacuum casting process to melt and blend material B into the injection mold. During this process, the blending temperature range needs to be controlled between 150 and 220°C. 7) The molten material B in the injection mold is kept at 80℃ / 0.5MPa for 60min, at 100℃ / 1MPa for 60min, and at 120℃ / 2MPa for 60min, for a total of 180min in an incremental gradient curing process to obtain the cured density body. 8) Wrap the density material with PE stretch film, continue to cure at 25℃ / normal pressure for 720 minutes, and then place it in a constant temperature and humidity environment to cool and stabilize for 36 hours; 9) Perform a CT value test on the cooled density body. If the CT value is stable within ±10HU, it is considered qualified. 10) Cut the qualified density body into standard-sized body modules 2 and integrate them into the mold frame 1.

[0056] Based on the above scheme, the injection mold is prepared through the following steps: a) After passing the material B obtained in step 5 through a sieve, it is sent back into the air shower dryer for 30 minutes to dry and obtain material C. b) Mix 10% (w / w) of material C, 85% (w / w) of PMMA and 5% (w / w) of hydroxyapatite nanoparticles at a rate of 150 R / min and then feed them into an injection molding machine for molding. During this process, the equipment temperature range needs to be controlled between 150 and 220°C. c) The injection-molded material C is kept at 80℃ / 0.5MPa for 60min, at 100℃ / 1MPa for 60min, and at 120℃ / 2MPa for 60min, for a total of 180min in an incremental gradient curing process to obtain the cured injection mold. d) The injection mold is wrapped with PE stretch film and cured, and then cured at 25℃ / normal pressure for 720 min. After that, it is placed in a constant temperature and humidity environment to cool and stabilize for 48 hours to obtain the injection mold.

[0057] The phantom frame of Example 5 was sent to CT for detection. Under the perfusion scanning conditions of 80kVp / 80mAs, the CT value was varied between +35 and +45 HU, which can accurately reflect the perfusion status of brain tissue and provide reliable imaging evidence for the early diagnosis and treatment of stroke patients.

Claims

1. A polymer composite phantom for CT detection, characterized in that: It includes a phantom frame, on which at least one replaceable body module is disposed. The body module is made of at least two materials selected from polytetrafluoroethylene (PTFE), polypropylene (PP), polyurethane (PU), polyvinyl chloride (PVC) and polyethylene (PE), so that the CT values ​​of different body modules can cover the full range from -1000HU to +1200HU, and is used to simulate the density characteristics of different tissues and organs in the human body, as well as the specific density of specific diseases.

2. The polymer composite phantom for CT detection according to claim 1, characterized in that: The body module is made of at least two of the following polymer materials: 60-80% polytetrafluoroethylene (PTFE), 40-50% polypropylene (PP), 30-70% polyurethane (PU), 20-60% polyvinyl chloride (PVC), or 10-30% polyethylene (PE).

3. The polymer composite phantom for CT detection according to claim 1, characterized in that: The compound formulation of the body module is PTFE 40% + PU 60%, PP 50% + PVC 30% + PE 20%, PTFE 80% + PU 20%, PU 70% + PE 30%, PP 40% + PVC 60% or PU 50% + PE 50%.

4. The polymer composite phantom for CT detection according to any one of claims 1-3, characterized in that: The phantom frame is also provided with at least one main water phantom for simulating water density. The main water phantom is a multi-layer nested sleeve structure, and the detection volume can be infinitely changed by adjusting the water injection volume.

5. The polymer composite phantom for CT detection according to claim 4, characterized in that: The main water model body includes an outer shell and at least one layer of sleeve disposed in the inner cavity of the outer shell. The cross-section of the outer shell and each layer of sleeve is a concentric cylinder. Each layer of sleeve divides the inner cavity into a multi-layer nested sleeve structure. Each layer of sleeve is connected by a connecting channel at the bottom. By injecting or discharging water into each layer of sleeve, the volume of each layer of sleeve can be infinitely changed, while maintaining the geometric similarity between each layer of sleeve.

6. The polymer composite phantom for CT detection according to claim 5, characterized in that: The sleeve is equipped with an adjustment knob for manually adjusting the sleeve volume.

7. The polymer composite phantom for CT detection according to claim 5, characterized in that: The outer shell is made of polyvinyl chloride (PVC), and the sleeve is made of polypropylene (PP).

8. The polymer composite phantom for CT detection according to claim 5, characterized in that: The sleeve is equipped with a scale indicator and a quick-sealing interface.

9. The polymer composite phantom for CT detection according to claim 8, characterized in that: The quick-sealing interface is made of polymethyl methacrylate (PMMA) material.

10. The polymer composite phantom for CT detection according to claim 4, characterized in that: The phantom frame is equipped with an air reservoir for temperature compensation.

11. A method for preparing a polymeric composite phantom for CT detection according to any one of claims 1-10, characterized in that, Includes the following steps: 1) The selected polymer material is used as the matrix material and is initially dried to obtain a dried matrix body; 2) The dried substrate is fed into a mixing tank in proportion and premixed to obtain material A; 3) Weigh 0.1-0.8 parts of compatibilizer and feed it together with material A into a high-speed mixer for mixing; 4) Vacuum degas the mixed material A; 5) The vacuum-degassed material A is fed into a twin-screw extruder for physical blending and extrusion, and then ring-cut in water to obtain material B; 6) After drying material B, use a vacuum casting process to melt and blend material B into the injection mold; 7) The molten material B in the injection mold is heated and pressurized in a stepwise manner to achieve incremental gradient solidification and obtain a solidified density body; 8) Wrap the cured density material with PE stretch film to maintain the cured state, and then place it in a constant temperature and humidity environment to cool and stabilize it; 9) Perform a CT value test on the cooled density body. If the CT value is stable within ±10HU, it is considered qualified. 10) Cut the qualified density body into standard-sized body modules.

12. The method for preparing a polymer composite phantom for CT detection according to claim 11, characterized in that, Includes the following steps: 1) The selected polymer material is used as the matrix material and is initially dried to obtain a dry matrix with a moisture content of less than 5%; 2) The dried substrate is fed into a mixing tank in proportion and premixed for 30 minutes at 25±2℃ / normal pressure to obtain material A; 3) Weigh 0.1-0.8 parts of compatibilizer and feed it together with material A into a high-speed mixer and mix at a rate of 150 R / min; 4) Degas the mixed material A under vacuum at 60±5℃ / -0.08MPa for 45 minutes; 5) The vacuum-degassed material is fed into a twin-screw extruder for physical blending and extrusion. During this process, the temperature range of the extruder must be controlled at 150~220℃ and the temperature range of the water ring cutting must be controlled at 80~90℃ to obtain material B. 6) After drying material B for 30 minutes, use vacuum casting process to melt and blend material B into the injection mold. During this process, the blending temperature range needs to be controlled between 150 and 220°C. 7) The molten material B in the injection mold is kept at 80℃ / 0.5MPa for 60min, at 100℃ / 1MPa for 60min, and at 120℃ / 2MPa for 60min, for a total of 180min in an incremental gradient curing process to obtain the cured density body. 8) Wrap the density material with PE stretch film, continue to cure at 25℃ / normal pressure for 720 minutes, and then place it in a constant temperature and humidity environment to cool and stabilize for 36 hours; 9) Perform a CT value test on the cooled density body. If the CT value is stable within ±10HU, it is considered qualified. 10) Cut the qualified density body into standard-sized body modules.

13. The method for preparing a polymer composite phantom for CT detection according to claim 11 or 12, characterized in that, The injection mold is prepared by the following steps: a) After passing the material B obtained in step 5 through a sieve, send it back into the air shower dryer for drying to obtain material C; b) Mix 10% (w / w) of material C, 85% (w / w) of PMMA, and 5% (w / w) of hydroxyapatite nanoparticles, and then feed them into an injection molding machine for molding. c) The injection-molded material C is heated and pressurized in a stepwise manner to achieve incremental gradient curing, thereby obtaining a cured injection mold. d) Wrap the cured injection mold with PE stretch film, continue to maintain the cured state, and then place it in a constant temperature and humidity environment to cool, thus obtaining the injection mold.

14. The method for preparing a polymer composite phantom for CT detection according to claim 13, characterized in that, The injection mold is prepared by the following steps: a) After passing the material B obtained in step 5 through a sieve, it is sent back into the air shower dryer for 30 minutes to dry and obtain material C. b) Mix 10% (w / w) of material C, 85% (w / w) of PMMA and 5% (w / w) of hydroxyapatite nanoparticles at a rate of 150 R / min and then feed them into an injection molding machine for molding. During this process, the equipment temperature range needs to be controlled between 150 and 220°C. c) The injection-molded material C is kept at 80℃ / 0.5MPa for 60min, at 100℃ / 1MPa for 60min, and at 120℃ / 2MPa for 60min, for a total of 180min in an incremental gradient curing process to obtain the cured injection mold. d) The injection mold is wrapped with PE stretch film and cured, and then cured at 25℃ / normal pressure for 720 min. After that, it is placed in a constant temperature and humidity environment to cool and stabilize for 48 hours to obtain the injection mold.

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