Device for correcting registration precision of multi-modal imaging system
By employing high-density materials, this technology solves the existing technical problems and realizes a calibration device for multimodal imaging systems. Specifically, it is applied in the field of medical devices, including the registration device for multimodal imaging systems.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HAMAMATSU PHOTONICS MEDICAL TECH (LANGFANG) CO LTD
- Filing Date
- 2025-04-17
- Publication Date
- 2026-05-12
AI Technical Summary
Existing multimodal imaging systems suffer from problems during the calibration process, such as uneven distribution of radiation sources, position identification deviation, bubble effect, radioactive contamination, and difficulty in scaling, leading to inaccurate image registration.
The system employs a support structure, which includes at least four support rods and a point source housing. The point source is made of high-density material and can absorb the radioactive source solution to form a radioactive point source, simulating the three-dimensional structure of the human body, reducing interference, and ensuring positioning accuracy and safety.
It improves the accuracy of image registration, reduces the risk of radioactive contamination, and enhances the safety of the equipment and image clarity.
Smart Images
Figure CN224220154U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of medical devices, and more specifically, to a calibration device for the registration accuracy of a multimodal imaging system. Background Technology
[0002] Multimodal imaging technology utilizes different imaging techniques to create multidimensional and three-dimensional images of the same patient, resulting in more comprehensive and accurate medical image information. Common multimodal imaging techniques include PET-CT and SPECT-CT.
[0003] In PET-CT and SPECT-CT technologies, CT provides anatomical imaging, while PET / SPECT provides functional imaging. CT images can pinpoint the specific location of PET / SPECT images within the body, and attenuation correction can be applied to PET / SPECT images using CT images. This fusion technology leverages the advantages of both imaging techniques while compensating for their respective shortcomings, significantly increasing the amount of information obtained from the images. This enhances the sensitivity, specificity, and accuracy of disease diagnosis, enabling early diagnosis and assessment of treatment efficacy, achieving a synergistic effect greater than the sum of its parts.
[0004] During PET-CT and SPECT-CT operations, CT images and PET / SPECT images need to be precisely fused into a single image to achieve accurate lesion localization and attenuation correction. To ensure the accuracy, stability, and consistency of the equipment during manufacturing and use, and to guarantee the accuracy of image fusion, regular registration accuracy calibration is required. This necessitates the use of calibration models to perform registration accuracy calibration for PET-CT and SPECT-CT.
[0005] In existing technologies, calibration models primarily involve mixing Tc-99m solution with a high-density CT contrast agent in a specific ratio, and then injecting the mixture into multiple containers. Each container must contain a solution of equal volume, density, and radioactive source activity. Currently, the containers holding the mixture are generally cylindrical tubes or inverted cones, wider at the top and narrower at the bottom, such as CN103584878A and CN104665857A.
[0006] However, these solutions have the following shortcomings in practical operation:
[0007] 1. When the mixed solution is injected into the container, it is difficult to ensure that the injection volume of each container is consistent, which leads to inconsistent radioactive source activity of each point source, resulting in deviations in the identification of the position of each point source during the calibration process. Moreover, during the injection process, radioactive sources can easily adhere to the side wall of the container, resulting in a non-spherical distribution of radioactive sources, which will also lead to deviations in the identification of the position of each point source during the calibration process. Furthermore, air bubbles are prone to appear during the injection process, and the presence of air bubbles will also lead to inaccurate positioning.
[0008] 2. When the container is cylindrical or tapered (wider at the top and narrower at the bottom), the uneven distribution of the radiation source during 360° scanning by PET / SPECT and CT can lead to inaccurate positioning of the radiation source and make it impossible to determine the center coordinates of the radiation source.
[0009] 3. Since the radioactive source is liquid, it is prone to leakage during the injection process, causing radioactive contamination to the environment, personnel, and equipment, posing a safety hazard. Moreover, during the model's movement or during the scanning process, the internal radioactive source may shake, causing the container's sidewalls to become contaminated with the radioactive source. This can lead to inaccurate positioning of the radioactive source and increase the risk of leakage.
[0010] 4. Since the mixed solution has certain requirements for the ratio of radioactive source and contrast agent, the ratio of contrast agent and radioactive source needs to be strictly controlled. When the ratio is inaccurate, it will lead to unclear PET / SPECT and CT images, affecting the accuracy of registration correction. However, in actual operation, due to the short decay time of the radioactive source, it is very difficult to strictly control the ratio.
[0011] The content of the background section is merely technology known to the inventor and does not necessarily represent prior art in this field. Utility Model Content
[0012] To address at least one of the aforementioned technical problems, this application provides a calibration device for the registration accuracy of a multimodal imaging system, comprising:
[0013] The support includes at least four support rods, each of which has a point source receiving portion. The tops of the at least four support rods form a virtual three-dimensional structure, and each point source receiving portion is located at one of the top positions.
[0014] At least four point sources are respectively housed in at least four point source accommodating portions. The point sources are made of a high-density material with solution adsorption capacity. When the multimodal imaging system is calibrated using the calibration device, each point source absorbs a radioactive source solution.
[0015] In some embodiments of this application, the high-density material is a material with micropores dispersed in the matrix.
[0016] In some embodiments of this application, the density of the point source is greater than or equal to 2 g / cm³. 3 The porosity of the point source is greater than or equal to 20%.
[0017] In some embodiments of this application, the point source is made of at least one of maifanite, montmorillonite, kaolinite, illite, and synthetic molecular sieves.
[0018] In some embodiments of this application, the point source is a sphere, and the volume of the sphere is less than or equal to 10 mm. 3 .
[0019] In some embodiments of this application, the volume difference between any two point sources is within a predetermined range.
[0020] In some embodiments of this application, the bracket further includes a central support block, and at least four of the support rods are fixed on the central support block according to the distribution of the virtual three-dimensional structure.
[0021] In some embodiments of this application, the volume of the virtual three-dimensional structure is greater than or equal to four times the volume of the central support block.
[0022] In some embodiments of this application, the virtual three-dimensional structure is a polyhedron, and the central support block is a sphere or a polyhedron with the same shape as the virtual three-dimensional structure.
[0023] In some embodiments of this application, the portion where the central support block connects to the support rod is provided with a threaded hole, and one end of the support rod is provided with a first threaded post. The support rod and the central support block are screwed together through the threaded hole and the first threaded post.
[0024] In some embodiments of this application, the support includes eight struts, the vertices of which form a virtual cube structure; the central support block is also a cube structure.
[0025] The side length of the central support block is no more than 10cm, and the side length of the virtual cube structure is 20-40cm.
[0026] In some embodiments of this application, the point source receiving portion includes a receiving groove and a sealing head, the receiving groove being used to place the point source, and the sealing head being used to seal the point source in the receiving groove.
[0027] In some embodiments of this application, the receiving groove has a groove body, an inlet portion connected to the open end of the groove body, and a threaded portion disposed at the end of the inlet portion away from the groove body; both the inlet portion and the threaded portion are cylindrical; the sealing head is provided with a second threaded post, which can be connected to the threaded portion and form a seal for the inlet portion and the groove body.
[0028] In some embodiments of this application, the lateral dimension of the inner side of the opening end is equal to or greater than the maximum lateral dimension of the outer contour of the point source, and the difference is within 2 mm; the lateral dimension of the inner side of the inlet is equal to the lateral dimension of the inner side of the opening end; the lateral dimension of the inner side of the threaded portion is greater than the lateral dimension of the inner side of the opening end.
[0029] In some embodiments of this application, the sum of the longitudinal dimension of the inner side of the tank and the longitudinal dimension of the inner side of the inlet is equal to or greater than the maximum longitudinal dimension of the outer contour of the point source, and the difference is within 2 mm.
[0030] In some embodiments of this application, the point source is a sphere, and the inner side of the groove is a cylinder or has an arc surface.
[0031] In some embodiments of this application, the side of the sealing head is provided with an embossed pattern.
[0032] In some embodiments of this application, the support is made of a material with low absorption properties for gamma rays and X-rays.
[0033] In some embodiments of this application, the support is made of acrylic and / or carbon fiber.
[0034] In some embodiments of this application, the radioactive source solution is a Tc-99m radioactive source solution or an F-18 radioactive source solution.
[0035] In some embodiments of this application, the radioactivity concentration of the radioactive source solution is not less than 40 mCi / mL.
[0036] The correction device provided in this application includes a point source with solution adsorption capability. The point source can form a radioactive point source by fully absorbing the radioactive source solution. Moreover, the high density of the point source itself can replace the contrast agent for imaging under CT scan, eliminating the need to use a mixed solution of radioactive source and contrast agent.
[0037] Furthermore, the support includes at least four struts, the tops of which form a virtual three-dimensional structure. The point source is mounted on the apex of this virtual three-dimensional structure via the support, which can better simulate the three-dimensional structure of the human body in space, fully reflect the three-dimensional effect in space, and greatly reduce the interference of the support and other structures on the point source imaging during tomographic scanning. It can quickly locate the point source and thus use the point source for image registration correction.
[0038] Furthermore, since the radioactive source solution is adsorbed onto the point source, it will not contaminate the side wall of the calibration equipment and there are no air bubbles. Therefore, the calibration effect is more accurate and it will not leak into the environment, causing radioactive pollution to personnel, the environment, and equipment, making it highly safe.
[0039] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description
[0040] The accompanying drawings, which form part of this utility model, are used to provide a further understanding of this utility model. The illustrative embodiments of this utility model and their descriptions are used to explain this utility model and do not constitute an improper limitation of this utility model.
[0041] Figure 1 A three-dimensional structural schematic diagram of a calibration device for the registration accuracy of a multimodal imaging system provided in an embodiment of this application.
[0042] Figure 2 for Figure 1 The diagram shows a partial enlarged view of the calibration device.
[0043] Figure 3 for Figure 1 The diagram shows a partial disassembly of the calibration equipment.
[0044] Figure 4 A three-dimensional structural schematic diagram of a calibration device for registration accuracy of a multimodal imaging system provided in another embodiment of this application.
[0045] Figure 5 A three-dimensional structural schematic diagram of a calibration device for registration accuracy of a multimodal imaging system provided in another embodiment of this application.
[0046] Figure 6 This is a schematic diagram of the structure of the tank and the inlet provided in an embodiment of this application.
[0047] Figure 7 This is a process flow diagram for preparing a calibration device according to an embodiment of this application.
[0048] Figure 8This is a schematic diagram illustrating the application of the correction device shown in Figures 1 to 3 to a SPECT-CT system according to an embodiment of this application.
[0049] Figure 9 An image obtained by using a SPECT-CT system to perform SPECT tomography on a correction device, as provided in an embodiment of this application.
[0050] Figure 10 The image provided in one embodiment of this application is obtained after CT acquisition of a correction device using a SPECT-CT system.
[0051] Figure 11 The SPECT-CT fusion image obtained after correction using a correction device is provided in one embodiment of this application. Detailed Implementation
[0052] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of this application. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.
[0053] The following disclosure provides many different embodiments or examples for implementing different structures of this application. To simplify the disclosure, specific examples of components and installations are described below. Of course, these are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or installations discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.
[0054] It should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances. Furthermore, in the accompanying drawings, the thickness, proportions, and dimensions of the components have been exaggerated or reduced for the purpose of effectively describing the technical content.
[0055] The specific embodiments of this application will be described in more detail below with reference to the accompanying drawings and examples, so as to better understand the solution of this application and its advantages in various aspects. However, the specific embodiments and examples described below are for illustrative purposes only and are not intended to limit this application.
[0056] Figures 1-3 A calibration device 1 provided in one embodiment of this application is shown, including a bracket 10 and a point source 20.
[0057] Figures 1-3 In the illustrated embodiment, the support 10 includes eight support rods 11. The vertices of the eight support rods 11 form a virtual cube structure, and each support rod 11 is provided with a point source receiving part 111. Each point source receiving part 111 is located at the top of the support rod 11 and is used to receive a point source 20.
[0058] In other embodiments of this application, there need to be four or more support rods 11. For example, the bracket 10 may include four, five, six, seven or other numbers of support rods 11, and the tops of at least four support rods 11 can form a virtual three-dimensional structure. Figure 4 The present application shows a calibration device provided in another embodiment, which includes four support rods 11, the tops of which can form a virtual three-dimensional structure.
[0059] The point source 20 is mounted on the vertex of the virtual three-dimensional structure via the support 10, which can effectively simulate the three-dimensional structure of the human body in space and fully reflect the three-dimensional effect in space. Moreover, during tomographic scanning, the interference of the support 10 and other structures on the imaging of the point source 20 is greatly reduced, and the point source 20 can be quickly located, so as to use the point source 20 for image registration correction.
[0060] Figures 1-3 In the illustrated embodiment, the vertices of the eight support rods 11 form a virtual cube structure. This virtual cube structure can more accurately simulate the three-dimensional structure of the human body in space, fully demonstrating the three-dimensional effect. Furthermore, this structure ensures the consistency of the point source heights, which is more conducive to eliminating deviations in the identification of point source positions during the calibration process.
[0061] Point sources 20 are made of high-density materials with solution adsorption capabilities. When using calibration equipment 1 to calibrate the multimodal imaging system, each point source 20 absorbs a radioactive source solution. In this application, the point sources 20 can form radioactive point sources by fully absorbing the radioactive source solution. Furthermore, the high density of the point sources themselves allows them to replace contrast agents in CT scans, eliminating the need for a mixture of radioactive source and contrast agent. Moreover, because the point sources 20 are fixed, movement of the bed board, support, etc., will not cause movement of the radioactive source, thus ensuring the accuracy of the point source position. In addition, since the radioactive source solution is adsorbed onto the point sources 20, there is no liquid, therefore no air bubbles, and it will not contaminate the sidewalls of the calibration equipment, nor will it leak into the environment, causing radioactive contamination to personnel, the environment, or equipment.
[0062] Optionally, the high-density material is a material with micropores dispersed in the matrix; for example, the density of point source 20 can be greater than or equal to 2 g / cm³. 3 The density of the material is greater than that of a liquid, resulting in clearer images acquired by CT scans, which aids in localization and increases convenience. Optionally, the porosity of the point source 20 can be greater than or equal to 20%, ensuring a strong adsorption capacity for the radioactive source solution. In this application, porosity refers to the percentage of pore volume to total volume in a material. Further, optionally, the point source 20 is made of at least one of maifanite, montmorillonite, kaolinite, illite, and synthetic molecular sieves, all of which have a strong adsorption capacity for the radioactive source solution. Each point source 20 can be made of one of maifanite, montmorillonite, kaolinite, illite, and synthetic molecular sieves, and multiple point sources 20 can use the same or different materials.
[0063] Figures 1-3 In the illustrated embodiment, the point source 20 is a sphere. A sphere is easy to manufacture and place, and its spherical structure helps ensure uneven distribution of the radiation source, thereby eliminating anisotropy problems. Optionally, the volume of the sphere is less than or equal to 10 mm². 3 The small volume of the sphere reduces the overall weight of the calibration device. Optionally, the volume difference between any two point sources 20 is within a predetermined range, and a regular shape helps reduce position identification errors caused by inconsistent distribution of radiation sources. In other embodiments of this application, the point source 20 may also be a cube, cuboid, or other shape, and this application does not impose any restrictions on this.
[0064] Optionally, the support 10 is made of a material with low absorption properties for gamma rays and X-rays, such as acrylic and / or carbon fiber. The low absorption properties of the material reduce interference from the support and other structures on point source sphere imaging, thereby enabling rapid point localization during scanning.
[0065] Optionally, the radioactive source solution is a Tc-99m radioactive source solution or an F-18 radioactive source solution. When the calibration equipment is used for a SPECT-CT system, the radioactive source solution corresponds to a Tc-99m radioactive source solution; when the calibration equipment is used for a PET-CT system, the radioactive source solution corresponds to an F-18 radioactive source solution. Optionally, the radioactivity concentration of the radioactive source solution is not less than 40 mCi / mL, thereby ensuring rapid localization during scanning.
[0066] Figures 1-3 In the illustrated embodiment, the support 10 further includes a central support block 12, with eight support rods 11 located at the eight vertices of the central support block 12. The central support block 12 provides better support for the support 10, thereby ensuring the stability of the calibration device 1. Figures 1-3 In the illustrated embodiment, the central support block 12 is also a cubic structure. In other embodiments of this application, the central support block 12 may also have other structures, with at least four support rods 11 fixed to the central support block according to the distribution of the virtual three-dimensional structure formed by their tops. The virtual three-dimensional structure is a polyhedron, and the preferred structure of the central support block is a sphere or a polyhedron with the same shape as the virtual three-dimensional structure, which is beneficial for forming a stable structure. Figure 4 In the embodiment shown, the central support block 12 is spherical, and the tops of the four support rods 11 form a virtual three-dimensional structure. Figure 5 The present application shows a calibration device provided in another embodiment, wherein the central support block 12 is also spherical, and eight support rods 11 are respectively located on the spherical central support block 12, and the eight support rods 11 constitute a cube structure.
[0067] Optionally, the volume of the virtual three-dimensional structure formed by at least four support rods 11 at their tops is greater than or equal to four times the volume of the central support block 12. The relatively small volume of the central support block 12 avoids deformation due to the gravity of the support rods 11 and reduces scattering and attenuation of rays passing through it. For Figures 1-3 In the illustrated embodiment, the side length of the central support block 12 can be no greater than 10cm, and the side length of the virtual cube structure can be 20-40cm. When a human body lies down, the width of the body is approximately 20-40cm. Setting the side length of the virtual cube within this range helps to better simulate the three-dimensional structure of the human body in space.
[0068] like Figure 3 As shown, in this embodiment, each vertex of the central support block 12 is provided with a threaded hole 121, and the other end of the support rod 11 opposite to the power source receiving part 111 is provided with a first threaded post 112. The support rod 11 and the central support block 12 are screwed together through the threaded hole 121 and the first threaded post 112. The threaded connection makes replacement convenient.
[0069] like Figure 2As shown, the point source receiving unit 111 includes a receiving groove 1111 and a sealing head 1112. The receiving groove 1111 is used to place the point source 20, and the sealing head 1112 is used to seal the point source 20 in the receiving groove 1111. This structure facilitates the placement and removal of the point source, and once fixed, the point source will not shake or move due to the movement of the bed board, support, etc., thus ensuring the accuracy of the point source position, guaranteeing a good sealing effect, and improving safety.
[0070] The receiving groove 1111 has a groove body 1111a, an inlet portion 1111b connected to the open end of the groove body 1111a, and a threaded portion 1111c provided at the end of the inlet portion 1111b away from the groove body 1111a. Figure 2 In the embodiment shown, the groove 1111a is hemispherical, and the inlet 1111b and the threaded part 1111c are both cylindrical.
[0071] Optionally, in order to ensure that the point source 20 is smoothly placed and fixed in the receiving groove 1111, the lateral dimension of the inner side of the opening end of the groove 1111a is equal to or greater than the maximum lateral dimension of the outer contour of the point source 20, and the difference is within 2 mm. Optionally, the lateral dimension of the inner side of the inlet 1111b is equal to the lateral dimension of the inner side of the opening end of the groove 1111a, which is beneficial for fixing it in the receiving groove 1111. Of course, the lateral dimension of the inner side of the inlet 1111b can also be greater than the lateral dimension of the inner side of the opening end of the groove 1111a, without hindering the point source 20 from being placed into the groove 1111a. Optionally, the lateral dimension of the inner side of the threaded portion 1111c is larger than the lateral dimension of the inner side of the opening end of the groove 1111a. This is because the threaded portion 1111c needs to be provided with internal threads. If the inner dimension is smaller than the lateral dimension of the inner side of the opening end, the point source may not be able to be placed. In addition, it can also ensure that the threaded portion 1111c completely covers the inlet portion 1111b, thereby sealing it. Optionally, the sum of the longitudinal dimension of the inner side of the groove 1111a and the longitudinal dimension of the inner side of the inlet portion 1111b is equal to or greater than the maximum longitudinal dimension of the outer contour of the point source 20, and the difference is within 2mm. This can ensure that when the point source 20 is placed in the receiving groove 1111, it is completely within the space formed by the groove 1111a and the inlet portion 1111b, without hindering the engagement between the threaded portion and the second threaded post on the sealing head, ensuring the sealing effect, and fixing the point source 20 so that the point source 20 will not shake when moved.
[0072] For example, in Figures 1-3In the illustrated embodiment, the lateral dimension inside the opening end of the groove 1111a and the lateral dimension inside the inlet 1111b can be equal to or greater than the diameter of the point source 20, with a difference of less than 2 mm. The longitudinal dimension inside the inlet 1111b can be greater than or equal to the longitudinal dimension inside the groove 1111a. The sum of the longitudinal dimension inside the groove 1111a and the longitudinal dimension inside the inlet 1111b can be equal to or greater than the diameter of the point source 20, with a difference of less than 2 mm. The lateral dimension inside the threaded portion 1111c can be greater than the diameter of the point source 20.
[0073] Figure 6 The state is shown when the point source 20 is placed in the space formed by the tank 1111a and the inlet 1111b. Figure 6 In the diagram, the tank 1111a is represented by a dashed line, and the inlet 1111b is represented by a solid line. For example... Figure 6 As shown, the inner side of the inlet 1111b can be any cylindrical shape, such as a triangular prism or a square prism. Ideally, the shape of the inlet 1111b should match the shape of the point source 20. Similarly, the threaded part 1111c can also be any cylindrical shape, preferably matching the shape of the point source 20. For example, Figures 1-3 In the embodiment shown, the point source 20 is a sphere, and the inlet portion 1111b and the threaded portion 1111c are both cylinders.
[0074] Figure 6 The dashed line L in the diagram represents the possible shape of the bottom (inner side) of the groove 1111a. When the point source 20 is a sphere, the inner side of the groove 1111a can be a cylinder or have an arc surface. Preferably, the groove 1111a is hemispherical, and the diameter of the arc surface of the groove bottom L is equal to or slightly larger than the diameter of the point source 20. After the point source 20 is placed, half of the spherical surface of the point source 20 rests against the arc surface of the groove bottom L, thus fixing the point source 20 more securely. In other embodiments of this application, the groove 1111a can be a cylinder with an arc shape, and the diameter of the arc surface of the groove bottom L is larger than the diameter of the point source 20. After the point source 20 is placed, part of the arc surface of the point source 20 rests against the arc surface of the groove bottom L. In other embodiments of this application, the groove 1111a can be a cylinder, and the groove bottom L is a plane. After the point source 20 is placed, the lowest point of the point source 20 rests against the surface of the groove bottom L. In other embodiments of this application, various changes can be made to the structure of the point source 20, as long as it can serve to accommodate and fix the point source 20.
[0075] Figures 1-3In the illustrated embodiment, the sealing head 1112 is provided with a second threaded post 1112a, which can be connected to the threaded portion 1111c and form a seal between the inlet portion 1111b and the groove 1111a. The sealing head and the receiving groove are easily replaced due to the threaded connection. The side of the sealing head 1112 is provided with embossed patterns 1112b, which are designed to increase friction and facilitate the disassembly of the sealing head.
[0076] The correction device provided in this application includes a point source with solution adsorption capability. The point source can form a radioactive point source by fully absorbing the radioactive source solution. Moreover, the high density of the point source itself can replace the contrast agent in CT scanning imaging, eliminating the need for a mixed solution of radioactive source and contrast agent. Furthermore, the high density of the point source makes the images acquired by CT clearer, which helps with localization and increases convenience.
[0077] Furthermore, the support system comprises at least four struts, the tops of which form a virtual three-dimensional structure. The point source is mounted on the apex of this virtual three-dimensional structure via the support system, which better simulates the three-dimensional structure of the human body in space, fully demonstrating the three-dimensional effect. Moreover, during tomographic scanning, it significantly reduces interference from the support system and other structures on the point source imaging, enabling rapid positioning of the point source and preventing deviations in point source location identification during calibration. This allows for image registration correction using the point source. The point source is fixed within the point source housing of the struts, preventing movement of the radiation source due to movement of the bed board or support system, thus ensuring the accuracy of the point source position.
[0078] Furthermore, since the radioactive source solution is adsorbed onto the point source, it will not contaminate the side wall of the calibration equipment and there are no air bubbles. Therefore, the calibration effect is more accurate and it will not leak into the environment, causing radioactive pollution to personnel, the environment, and equipment, making it highly safe. Figure 7 A method for preparing the above-mentioned calibration device according to an embodiment of this application is shown, which includes the following steps S1 to S3.
[0079] S1: Preparation point source.
[0080] In step S1, a point source made of a high-density material with solution adsorption capacity is immersed in a radioactive source solution for a predetermined time.
[0081] After being immersed in the radioactive source solution for a predetermined time, the point source can fully absorb the radioactive source solution. As mentioned earlier, the high-density material can be a material with micropores dispersed in the matrix; for example, the density of the point source can be greater than or equal to 2 g / cm³. 3The porosity can be greater than or equal to 20%. The point source is made of a high-density material, which is denser than a liquid, making the images acquired by CT clearer and aiding in localization. Furthermore, it eliminates the need for density control, increasing convenience. Optionally, the point source is made of at least one of maifanite, montmorillonite, kaolinite, illite, or synthetic molecular sieves, materials that have a strong adsorption capacity for the radioactive source solution.
[0082] As mentioned earlier, when the calibration device is used in a SPECT-CT system, the corresponding radioactive source solution is Tc-99m radioactive source solution; when the calibration device is used in a PET-CT system, the corresponding radioactive source solution is F-18 radioactive source solution.
[0083] S2: Fabrication of the scaffold.
[0084] In step S2, at least four support rods are prepared, and each support rod has a point source receiving part that matches the point source structure. The specific structure of the point source receiving part is as described above and will not be repeated here.
[0085] S3: Assembly.
[0086] In step S3, the point sources can be first installed into the point source receiving parts; then at least four support rods are assembled so that the tops of the at least four support rods form a virtual three-dimensional structure, and each point source receiving part is located at a top position.
[0087] The preparation method provided in this application is simple and easy to operate. The resulting calibration device includes a point source with solution adsorption capacity. The point source can form a radioactive point source by fully absorbing the radioactive source solution. Moreover, the high density of the point source itself can replace the contrast agent in CT scanning, eliminating the need for a mixed solution of radioactive source and contrast agent and avoiding a series of effects caused by using a mixed solution. Furthermore, the support includes at least four struts, the top of which forms a virtual three-dimensional structure. The point source is mounted on the apex of this virtual three-dimensional structure by the support, which can better simulate the three-dimensional structure of the human body in space, fully reflecting the three-dimensional effect in space. Moreover, during tomographic scanning, the interference of the support and other structures on the point source imaging is greatly reduced, and the point source can be quickly located, thereby using the point source for image registration correction.
[0088] In one embodiment of this application, preparation Figures 1-3 The method of the calibration device 1 shown is as follows:
[0089] Eight volumes no larger than 10mm 3The point sources 20 are immersed in a Tc-99m or F-18 radioactive source solution with a radioactivity concentration of not less than 40 mCi / mL for more than ten minutes to allow them to fully absorb the radioactive source solution. Then, these eight point sources 20 are placed into the spaces formed by the hemispherical grooves 1111a and cylindrical inlets 1111b of the eight support rods 11, and then the eight point sources 20 are sealed inside the eight support rods 11 using eight sealing heads 1112. Finally, the eight support rods 11 are fixed to the eight vertices of the central support block 12, completing the fabrication process.
[0090] This application further provides the application of the aforementioned calibration device in correcting the registration accuracy of a multimodal imaging system. Optionally, the multimodal imaging system includes a SPECT-CT system or a PET-CT system.
[0091] Figure 8 This application illustrates an embodiment of the correction device 1 shown in Figures 1 to 3, which is applied to a SPECT-CT system. Figure 8 The SPECT-CT system shown includes a SPECT unit 2, a CT unit 3, two gantry detectors 4, a support bed 5, and a bed 6.
[0092] During calibration, the calibration device 1 is first placed at five positions on the support bed 5 of the SPECT-CT system, with these five positions evenly spaced across the entire support bed. After each placement, the SPECT-CT system scans the calibration device 1 to obtain five sets of first images from the SPECT imaging system and five sets of second images from the CT imaging system. Before calibration, the height of the examination bed 6 needs to be adjusted so that the center of the calibration device 1 is aligned with the rotation axis of the SPECT-CT system. Then, the support bed 5 is extended so that the center of the calibration device 1 coincides with the center of the imaging field of view of the SPECT detector 4. Figure 9 and Figure 10 The image is obtained by SPECT and CT acquisition from a point source of the calibration device 1 at the position closest to the gantry detector 4 among the five positions of the support bed plate 5.
[0093] Then, filtered backprojection is used to perform 3D reconstruction on each of the five sets of first images, thereby obtaining five sets of first 3D image data corresponding to five locations. Next, based on each set of first 3D image data, the first pixel value contour line of each point source in each direction of the XYZ coordinate system is determined, and the first centroid of the first pixel value contour line in each direction is calculated using the centroid method. Then, the coordinate values of each first centroid in the XYZ coordinate system are determined, thereby obtaining the first coordinates, and thus obtaining the first coordinate set. The first coordinate set includes 40 coordinates in each of the X, Y, and Z directions, for a total of 120 coordinates. Then, the same method is used to obtain the second coordinate set. Similarly, the second coordinate set includes 40 coordinates in each of the X, Y, and Z directions, for a total of 120 coordinates.
[0094] The first coordinate set and the second coordinate set can be represented as follows:
[0095]
[0096] Among them, X Sij Y Sij Z Sij X represents the coordinates of the i-th point source at the j-th position in the first imaging system. Cij Y Cij Z Cij Let represent the coordinates of the i-th point source at the j-th position in the second imaging system, where 1≤i≤8 and 1≤j≤5.
[0097] Then, based on the coordinates in the first and second coordinate sets, the spatial coordinate correction factors ΔX of the SPECT imaging system in the X, Y, and Z directions are obtained. Sij ΔY Sij ΔZ Sij Alternatively, obtain the spatial coordinate correction factor ΔX of the CT imaging system in the X, Y, and Z directions. Cij ΔY Cij ΔZ Cij .
[0098] When acquiring SPECT-CT images subsequently, a spatial coordinate correction factor ΔX is used. Sij ΔY Sij ΔZ Sij The images acquired by the SPECT imaging system are corrected, or a spatial coordinate correction factor ΔX is used. Cij ΔY Cij ΔZ Cij Correcting the images acquired by the CT imaging system completes the calibration. The calibrated images ensure that the deviation between the SPECT imaging system and the CT imaging system is within 2mm. Figure 11The illustration shows a SPECT-CT fusion image obtained after correction according to an embodiment of this application. The position of the fused SPECT image and the CT image is almost identical.
[0099] The above descriptions are merely illustrative embodiments of this application and are not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.
[0100] As can be understood from the description of the above embodiments, this specification includes disclosures in the following ways.
[0101] [Postscript 1]
[0102] A device for correcting the registration accuracy of a multimodal imaging system, comprising:
[0103] The support includes at least four support rods, each of which has a point source receiving portion. The tops of the at least four support rods form a virtual three-dimensional structure, and each point source receiving portion is located at one of the top positions.
[0104] At least four point sources are respectively housed in at least four point source accommodating portions. The point sources are made of a high-density material with solution adsorption capacity. When the multimodal imaging system is calibrated using the calibration device, each point source absorbs a radioactive source solution.
[0105] [Postscript 2]
[0106] According to the calibration device described in Appendix 1, the high-density material is a material with micropores dispersed in the matrix;
[0107] Optionally, the density of the point source is greater than or equal to 2 g / cm³. 3 The porosity of the point source is greater than or equal to 20%;
[0108] Optionally, the point source is made from at least one of maifanite, montmorillonite, kaolinite, illite, and synthetic molecular sieves.
[0109] [Postscript 3]
[0110] According to the calibration device described in Appendix 1, the point source is a sphere, and the volume of the sphere is less than or equal to 10 mm. 3 ;
[0111] Optionally, the volume difference between any two point sources is within a predetermined range.
[0112] [Postscript 4]
[0113] According to the calibration device described in Appendix 1 or 2, the bracket further includes a central support block, and at least four of the support rods are fixed on the central support block according to the distribution of the virtual three-dimensional structure;
[0114] Optionally, the volume of the virtual three-dimensional structure is greater than or equal to four times the volume of the central support block;
[0115] Optionally, the virtual three-dimensional structure is a polyhedron, and the central support block is a sphere or a polyhedron with the same shape as the virtual three-dimensional structure.
[0116] Optionally, the central support block is provided with a threaded hole at the connection point with the support rod, and a first threaded post is provided at one end of the support rod. The support rod and the central support block are screwed together through the threaded hole and the first threaded post.
[0117] [Postscript 5]
[0118] According to the calibration device described in Appendix 4, the support includes eight rods, the vertices of which form a virtual cube structure; the central support block is also a cube structure.
[0119] The side length of the central support block is no more than 10cm, and the side length of the virtual cube structure is 20-40cm.
[0120] [Postscript 6]
[0121] According to the calibration device described in Appendix 1 or 2, the point source receiving part includes a receiving groove and a sealing head, the receiving groove being used to place the point source, and the sealing head being used to seal the point source in the receiving groove.
[0122] [Postscript 7]
[0123] According to the calibration device described in Appendix 6, the receiving groove has a groove body, an inlet portion connected to the open end of the groove body, and a threaded portion disposed at the end of the inlet portion away from the groove body; both the inlet portion and the threaded portion are cylindrical; the sealing head is provided with a second threaded post, which can be connected to the threaded portion and form a seal for the inlet portion and the groove body;
[0124] Optionally, the lateral dimension of the inner side of the opening end is equal to or greater than the maximum lateral dimension of the outer contour of the point source, and the difference is within 2mm; the lateral dimension of the inner side of the inlet is equal to the lateral dimension of the inner side of the opening end; the lateral dimension of the inner side of the threaded portion is greater than the lateral dimension of the inner side of the opening end.
[0125] Optionally, the sum of the longitudinal dimension of the inner side of the tank and the longitudinal dimension of the inner side of the inlet is equal to or greater than the maximum longitudinal dimension of the outer contour of the point source, and the difference is within 2 mm.
[0126] Optionally, the point source is a sphere, and the inner side of the groove is a cylinder or has an arc surface.
[0127] Optionally, the side of the sealing head is provided with an embossed pattern.
[0128] [Postscript 8]
[0129] According to the calibration device described in Appendix 1 or 2, the support is made of a material with low absorption characteristics for gamma rays and X-rays;
[0130] Optionally, the support is made of acrylic and / or carbon fiber.
[0131] [Postscript 9]
[0132] According to the calibration device described in Appendix 1 or 2, the radioactive source solution is a Tc-99m radioactive source solution or an F-18 radioactive source solution;
[0133] Optionally, the radioactivity concentration of the radioactive source solution is not less than 40 mCi / mL.
Claims
1. A calibration device for registration accuracy of a multimodal imaging system, characterized in that, include: The support includes at least four support rods, each of which is provided with a point source receiving part. The tops of the at least four support rods form a virtual three-dimensional structure, and each point source receiving part is located at one of the top positions. as well as At least four point sources are respectively housed in at least four point source accommodating portions. The point sources are made of a high-density material with solution adsorption capacity. When the multimodal imaging system is calibrated using the calibration device, each point source absorbs a radioactive source solution.
2. The calibration device according to claim 1, characterized in that, The high-density material is a material with micropores distributed in its matrix; Optionally, the point source is made from at least one of maifanite, montmorillonite, kaolinite, illite, and synthetic molecular sieves.
3. The calibration device according to claim 1 or 2, characterized in that, The point source is a sphere, and the volume of the sphere is less than or equal to 10 mm. 3 ; Optionally, the volume difference between any two point sources is within a predetermined range.
4. The calibration device according to claim 1 or 2, characterized in that, The bracket also includes a central support block, and at least four of the support rods are fixed on the central support block according to the distribution of the virtual three-dimensional structure. Optionally, the volume of the virtual three-dimensional structure is greater than or equal to four times the volume of the central support block; Optionally, the virtual three-dimensional structure is a polyhedron, and the central support block is a sphere or a polyhedron with the same shape as the virtual three-dimensional structure. Optionally, the central support block is provided with a threaded hole at the connection point with the support rod, and a first threaded post is provided at one end of the support rod. The support rod and the central support block are screwed together through the threaded hole and the first threaded post.
5. The calibration device according to claim 4, characterized in that, The support structure includes eight rods, the vertices of which form a virtual cube structure; the central support block is also a cube structure. The side length of the central support block is no more than 10cm, and the side length of the virtual cube structure is 20-40cm.
6. The calibration device according to claim 1 or 2, characterized in that, The point source receiving part includes a receiving groove and a sealing head. The receiving groove is used to place the point source, and the sealing head is used to seal the point source in the receiving groove.
7. The calibration device according to claim 6, characterized in that, The receiving groove has a groove body, an inlet portion connected to the open end of the groove body, and a threaded portion disposed at the end of the inlet portion away from the groove body; both the inlet portion and the threaded portion are cylindrical; the sealing head is provided with a second threaded post, which can be connected to the threaded portion and form a seal for the inlet portion and the groove body; Optionally, the lateral dimension of the inner side of the opening end is equal to or greater than the maximum lateral dimension of the outer contour of the point source, and the difference is within 2mm; the lateral dimension of the inner side of the inlet is equal to the lateral dimension of the inner side of the opening end; the lateral dimension of the inner side of the threaded portion is greater than the lateral dimension of the inner side of the opening end. Optionally, the sum of the longitudinal dimension of the inner side of the tank and the longitudinal dimension of the inner side of the inlet is equal to or greater than the maximum longitudinal dimension of the outer contour of the point source, and the difference is within 2 mm. Optionally, the point source is a sphere, and the inner side of the groove is a cylinder or has an arc surface; Optionally, the side of the sealing head is provided with an embossed pattern.
8. The calibration device according to claim 1 or 2, characterized in that, The support is made of a material with low absorption properties for gamma rays and X-rays; Optionally, the support is made of acrylic and / or carbon fiber.
9. The calibration device according to claim 1 or 2, characterized in that, The radioactive source solution is either a Tc-99m radioactive source solution or an F-18 radioactive source solution.