Energy spectrum CT quality control die body based on PMMA material

Abstract

The invention discloses an energy spectrum CT (Computed Tomography) quality control die body based on a PMMA (Polymethyl Methacrylate) material, and belongs to the technical field of medical image quality control. The material separation module, the energy spectrum curve and effective atomic number module, the single energy image module and the pure water module are sequentially arranged in the die body; the substance separation module comprises five chambers; the energy spectrum curve and effective atomic number module comprises six cavities; the single-energy image module comprises a central artifact source and four concentric circular ring cavities; the system is used for verifying the performance of an energy spectrum computed tomography (CT) system, and through the modular design, the comprehensive test of the material separation capacity, the single energy imaging quality, the imaging uniformity, the energy spectrum curve accuracy, the effective atomic number measurement and the artifact inhibition effect can be realized; the die body and the modules are complete in function, modular design is achieved, and the die body and the modules are suitable for performance verification and daily quality control of energy spectrum CT equipment.

Description

Technical Field

[0001] The invention relates to the technical field of medical image quality control, and in particular to an energy spectrum CT quality control phantom based on PMMA material. Background Art

[0002] Spectral CT can achieve material separation, single energy imaging, effective atomic number calculation, energy spectrum curve analysis and artifact suppression by decomposing X-ray attenuation information at different energy levels; Traditional quality control phantoms are mostly used for ordinary CT and cannot meet the comprehensive verification of the spectral CT system for material separation, single-energy imaging, effective atomic number calculation, spectral curve analysis and artifact suppression effects. It is urgent to develop a multifunctional quality control phantom to achieve a comprehensive evaluation of the performance of spectral CT equipment.

[0003] Based on this, the present invention designs an energy spectrum CT quality control phantom based on PMMA material to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to provide a PMMA-based spectral CT quality control phantom to solve the above technical problems.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a PMMA-based spectral CT quality control phantom, comprising: a phantom made of PMMA material; and also comprising a material separation module, a spectrum curve and effective atomic number module, a single energy image module and a pure water module sequentially arranged in the phantom; The substance separation module includes five chambers, and the five chambers are evenly distributed in a circular area with a radius of 5 cm in the center of the module and are filled with iodine solution; The energy spectrum curve and effective atomic number module includes six chambers, five of which are evenly distributed on the periphery and filled with iodine solution and pure water, and the central chamber is empty; The single-energy imaging module includes a central artifact source embedded with uniformly arranged metal wires and four concentric ring chambers filled with iodine solution and pure water, respectively; The pure water module is an independent module, which is completely filled with pure water.

[0006] Preferably, an upper shell is provided at the top of the mold body and a lower shell is provided at the bottom end, a sealing screw is threadedly connected in the cavity of the mold body, a plurality of positioning slots are sequentially opened on the outer wall of the upper shell and a suspension arm is fixed at the center position, and the upper shell, lower shell, suspension arm, the main body of the material separation module and the main body of the pure water module are also made of PMMA material.

[0007] Preferably, the five chambers of the substance separation module each have a diameter of 20 mm and a depth of 30 mm, and are filled with 1 mg / mL, 1 mg / mL, 5 mg / mL, 10 mg / mL, and 20 mg / mL iodine solutions, respectively.

[0008] Preferably, the six chambers of the energy spectrum curve and effective atomic number module have a diameter of 20 mm and a depth of 30 mm, and the five chambers distributed on the periphery are filled with 20 mg / mL, 15 mg / mL, 10 mg / mL iodine solution and pure water in sequence.

[0009] Preferably, the central artifact source of the single-energy imaging module has a tungsten wire embedded in the uniformly arranged metal wire with a diameter of 0.1 mm, and its four concentric ring chambers are filled with 5 mg / mL, 5 mg / mL, 10 mg / mL iodine solution and pure water respectively.

[0010] Preferably, a water injection hole is opened on the outer wall of the pure water module, and the whole is a cylinder with a diameter of 14 cm and a thickness of 4 cm.

[0011] Compared with the prior art, the present invention has the following beneficial effects: First, the phantom adopts a cylindrical structure and is divided into four modules: material separation module, single energy imaging module, pure water module, energy spectrum curve and effective atomic number module. Through modular design, comprehensive testing of material separation capability, single energy imaging quality, imaging uniformity, energy spectrum curve accuracy, effective atomic number measurement and artifact suppression effect can be achieved. The phantom is fully functional and modularly designed, and is suitable for performance verification and daily quality control of energy spectrum CT equipment; Second, each module is designed with multiple chambers, which are filled with iodine solutions or pure water of different concentrations, and embedded with cross-arranged metal tungsten wires to simulate complex artifact sources. Through scanning and data analysis, the performance of spectral CT in material separation, accuracy of spectral curves, single energy images, artifact suppression effects, and effective atomic number calculations is verified. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0013] Figure 1 This is a structural diagram of the appearance of the phantom in the embodiment; Figure 2 This is a schematic diagram of the chamber layout of the substance separation module in the embodiment; Figure 3It is a schematic diagram of the energy spectrum curve and the effective atomic number module test in the embodiment; Figure 4 Schematic diagram of the artifact structure of the single energy image module in the embodiment; Figure 5 This is a schematic diagram of the structure of the pure water module in the embodiment; Figure 6 This is a schematic diagram of the structure of the lower shell of the mold body in the embodiment; Figure 7 Schematic diagram of the upper shell structure of the mold body in the embodiment; Figure 8 Schematic diagram of the mold cavity structure in the embodiment.

[0014] In the accompanying drawings, the components represented by the reference numerals are listed as follows: 1. Suspension arm; 2. Material separation module; 3. Energy spectrum curve and effective atomic number module; 4. Single energy image module; 5. Pure water module; 6. Water injection hole; 7. Positioning slot; 8. Sealing screw; 9. Tungsten wire; 10. Upper shell; 11. Lower shell. DETAILED DESCRIPTION

[0015] 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.

[0016] like Figure 1-8 As shown: One embodiment of the present invention is: A PMMA-based phantom that can be used for quality control of various functions of spectral CT is provided, comprising: a phantom 1 made of PMMA material; and also comprising a material separation module 2, a spectrum curve and effective atomic number module 3, a single energy image module 4, and a pure water module 5 that are sequentially arranged in the phantom 1; The substance separation module 2 includes five chambers, and the five chambers are evenly distributed in a circular area with a radius of 5 cm at the center of the module and are filled with iodine solution; The energy spectrum curve and effective atomic number module 3 includes six chambers, five of which are evenly distributed on the periphery and filled with iodine solution and pure water, and the central chamber is empty; The single energy imaging module 4 includes a central artifact source embedded with uniformly arranged metal wires and four concentric ring chambers filled with iodine solution and pure water respectively; Pure water module 5 is an independent module, which is completely filled with pure water; The quality control model 1 includes a material separation module 2, a single energy image module 4, an energy spectrum curve and effective atomic number module 3 and a pure water module 5, and each module can be tested independently.

[0017] Further preferably, an upper shell 10 is provided at the top of the mold body 1 and a lower shell 11 is provided at the bottom, a sealing screw 8 is threadedly connected in the chamber of the mold body 1, a plurality of positioning slots 7 are sequentially provided on the outer wall of the upper shell 10 and a suspension arm is fixed at the center, and the upper shell 10, the lower shell 11, the suspension arm, the main body of the substance separation module 2, and the main body of the pure water module 5 are also made of PMMA material; The mold body 1, the upper shell 10, the lower shell 11, the suspension arm, the main body of the material separation module 2, and the main body of the pure water module 5 are all made of PMMA material, which has good mechanical strength and X-ray absorption characteristics. The shell of the mold body 1 adopts a cylindrical structure, and the top of the upper shell 10 adopts a suspension slot to fix the suspension arm. The upper shell 10 includes an adjustable sealing screw 8 to ensure that the position of the mold body 1 can be adjusted to remain horizontal as needed.

[0018] Further preferably, the five chambers of the substance separation module 2 each have a diameter of 20 mm and a depth of 30 mm, and are filled with 1 mg / mL, 1 mg / mL, 5 mg / mL, 10 mg / mL, and 20 mg / mL of iodine solution, respectively.

[0019] Further preferably, the six chambers of the energy spectrum curve and effective atomic number module 3 have a diameter of 20 mm and a depth of 30 mm, and the five chambers distributed on the periphery are filled with 20 mg / mL, 15 mg / mL, 10 mg / mL iodine solution and pure water in sequence.

[0020] Further preferably, the central artifact source of the single-energy imaging module 4 has a tungsten wire 9 embedded in uniformly arranged metal wires with a diameter of 0.1 mm, and its four concentric ring chambers are filled with 5 mg / mL, 5 mg / mL, 10 mg / mL iodine solution and pure water respectively.

[0021] Further preferably, the outer wall of the pure water module 5 is provided with a water injection hole 6, and the whole is a cylinder with a diameter of 14 cm and a thickness of 4 cm; Pure water module 5 is mainly used for imaging uniformity testing and standard background correction.

[0022] The specific application of this embodiment is: the substance separation module 2 is used to generate an iodine-based map and a water-based map to verify the accuracy of the separation of iodine and water signals. The error between the iodine solution concentration measured in the iodine-based map and the actual iodine solution concentration shall not exceed ±5%, and the uniformity of the water-based map shall be within ±3 HU; Energy spectrum curve and effective atomic number module 3 is used to verify the consistency of energy spectrum curves of the same substance and the distinction between curves of different substances, and can measure the effective atomic number of the substances in the module. The slope and shape of the energy spectrum curve of each substance should be consistent with expectations, with an error of no more than ±5%, and the effective atomic number measurement error should not exceed ±5%; The single energy image module 4 is used to ensure that the device can generate high-quality single energy images at different energy levels, proving that single energy images can help reduce artifacts, enhance contrast and optimize image quality. The image with the best imaging quality at different energy levels is selected to measure its noise and artifacts. The noise level and detection method are based on the quality control inspection specifications of X-ray computed tomography devices, which can effectively suppress artifacts; Pure water module 5 is used to detect image uniformity at different energy levels of spectral CT. The detection method is based on the quality control and detection specifications of X-ray computed tomography devices. The water model CT value is within ±6HU. The positions of the modules in the phantom 1 can be adjusted as needed, and the installation sequence of the modules can also be adjusted according to actual conditions.

[0023] In the description of the present invention, it is necessary to understand that the terms indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0024] In the present invention, unless otherwise clearly specified and limited, the terms should be understood in a broad sense, and a person of ordinary skill in the art can understand the specific meaning of the terms in the present invention according to specific circumstances.

[0025] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A PMMA-based spectral CT quality control phantom, characterized in that: include: A phantom (1) made of PMMA material; further comprising a material separation module (2), an energy spectrum curve and effective atomic number module (3), a single energy image module (4) and a pure water module (5) which are sequentially arranged in the phantom (1); The substance separation module (2) comprises five chambers, and the five chambers are evenly distributed in a circular area with a radius of 5 cm at the center of the module and are filled with iodine solution; The energy spectrum curve and effective atomic number module (3) includes six chambers, five of which are evenly distributed on the periphery and filled with iodine solution and pure water, and the central chamber is empty; The single energy imaging module (4) includes a central artifact source embedded with uniformly arranged metal wires and four concentric ring chambers filled with iodine solution and pure water respectively; The pure water module (5) is an independent module, which is completely filled with pure water.

2. The PMMA-based spectral CT quality control phantom according to claim 1, characterized in that: The mold body (1) is provided with an upper shell (10) at the top and a lower shell (11) at the bottom. A sealing screw (8) is threadedly connected in the chamber of the mold body (1). The outer wall of the upper shell (10) is provided with a plurality of positioning slots (7) in sequence and a suspension arm is fixed at the center. The upper shell (10), the lower shell (11), the suspension arm, the main body of the material separation module (2), and the main body of the pure water module (5) are all made of PMMA material.

3. The PMMA-based spectral CT quality control phantom according to claim 1, characterized in that: The five chambers of the substance separation module (2) each have a diameter of 20 mm and a depth of 30 mm, and are filled with iodine solutions of 1 mg / mL, 1 mg / mL, 5 mg / mL, 10 mg / mL, and 20 mg / mL, respectively.

4. The PMMA-based spectral CT quality control phantom according to claim 1, characterized in that: The six chambers of the energy spectrum curve and effective atomic number module (3) have a diameter of 20 mm and a depth of 30 mm. The five chambers distributed on the periphery are filled with 20 mg / mL, 15 mg / mL, 10 mg / mL iodine solution and pure water respectively.

5. The PMMA-based spectral CT quality control phantom according to claim 1, characterized in that: The central artifact source of the single-energy imaging module (4) is a tungsten wire (9) embedded in a uniformly arranged metal wire with a diameter of 0.1 mm, and its four concentric ring chambers are filled with 5 mg / mL, 5 mg / mL, 10 mg / mL iodine solution and pure water respectively.

6. The PMMA-based spectral CT quality control phantom according to claim 1, characterized in that: The outer wall of the pure water module (5) is provided with a water injection hole (6), and the whole is a cylinder with a diameter of 14 cm and a thickness of 4 cm.

Images