Collimator, detector assembly and computed tomography imaging system

Abstract

The embodiment of the utility model provides a collimator, a detector assembly and a computed tomography imaging system. The collimator is applied to a detector assembly and comprises a collimator module, and the collimator module comprises a plurality of first bases arranged at intervals; the second bases are located between every two first bases; the plurality of first shielding plates are positioned on the first base; wherein the width of the second base is smaller than that of the first base, and the width of the first shielding plate is smaller than that of the first base. According to the embodiment of the invention, the first shielding plates (such as Z plates) of the collimator of the detector assembly are arranged at intervals, the widths of the first bases below the first shielding plates are relatively wide and are enough to cover the shadows of the first shielding plates, so that the operation performance can be ensured, in addition, the second base with the narrower width is arranged between the two first bases, and the detection efficiency is improved. The uniform performance of pixels can be ensured when X-rays pass through, and higher dosage efficiency can be obtained.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of medical equipment, and in particular to a collimator, a detector assembly, and a computed tomography imaging system. Background Art

[0002] Computed tomography (CT) is a medical imaging technology that uses X-rays to produce detailed images of the body's internal structures. The basic principle of CT scanning is to use an X-ray beam to scan layers of the human body at specific thicknesses. The intensity variations of the X-rays detected by the detector are converted into electrical signals. These signals are then converted to digital signals via an analog-to-digital converter and fed into a computer for processing.

[0003] During CT imaging, the selected slice is divided into many small cubes of equal volume, known as voxels. The X-ray attenuation coefficient or absorption coefficient for each voxel is calculated by a computer and arranged into a digital matrix. This digital matrix can be stored on a disk or CD and converted into pixels of varying grayscale using a digital-to-analog converter. The resulting matrix arrangement forms the CT image. Therefore, a CT image is a reconstructed image, and the X-ray absorption coefficient for each voxel can be mathematically calculated.

[0004] The detector is one of the core components of the CT system, referred to as the CT detector. It is mainly composed of a collimator or anti-scatter grid (ASG), a scintillator, a photodiode and a circuit board (ASIC, Application Specific Integrated Circuit). The working process of the CT detector is that X-rays enter the CT detector, the collimator blocks the scattered light of the X-rays, and the collimated X-rays pass through the scintillator and are converted from high-energy rays to low-energy visible light. The photodiode then converts the optical signal into an electrical signal, and finally the electronic circuit performs analog-to-digital conversion and outputs the digital signal. To improve image clarity, the scintillator needs to be used in conjunction with the collimator to reduce scattered light, thereby avoiding affecting the image quality.

[0005] It should be noted that the above introduction to the technical background is merely intended to provide a clear and complete description of the technical solutions of this application and facilitate understanding by those skilled in the art. Simply because these solutions are described in the background technology section of this application, it should not be assumed that the above technical solutions are well known to those skilled in the art. Utility Model Content

[0006] The inventors have discovered that dose is a very important parameter of a CT system. CT detectors (referred to as detectors) generally use "dose efficiency" to evaluate X-ray dose. Dose efficiency refers to the efficiency with which X-rays passing through the object are converted by the detector system. Dose efficiency is typically evaluated by the detector system based on the ratio of the energy of the X-rays emitted by the X-ray source (e.g., a tube) to the energy received by the detector. To reduce costs, the detector's collimator can use a 3D (three-dimensional) printed collimator. Furthermore, to ensure strength, this 3D-printed collimator can be designed as a 2D (two-dimensional) flat plate. That is, the detector only has shielding plates (also called shielding plates) in the X and Z directions. This means that the collimator's X-plate (which is used to separate the radiation emitted to the detector into units in the X-direction or channel direction, extending parallel to the Z direction) and Z-plate (which is used to separate the radiation emitted to the detector into units in the Z-direction or slice direction, extending parallel to the X direction) also need to be designed as a flat plate or grid. However, if the collimator has uniformly wide plates or grids of X-plates and Z-plates, more useful rays passing through the inspection object will be blocked, resulting in poor dose efficiency.

[0007] In order to solve at least one of the above problems or other similar problems, embodiments of the present application provide a collimator, a detector assembly, and a computed tomography imaging system to balance high dose efficiency and good performance.

[0008] According to one aspect of an embodiment of the present application, a collimator is provided. The collimator is applied to a detector assembly and includes a collimator module. The collimator module includes:

[0009] a plurality of first bases arranged at intervals;

[0010] a second base located between every two first bases; and

[0011] a plurality of first shielding plates located on the first base;

[0012] The width of the second base is smaller than that of the first base, and the width of the first shielding plate is smaller than that of the first base.

[0013] In some embodiments, the detector assembly includes a plurality of scintillators, and the first base and the second base are respectively located above a gap between every two scintillators.

[0014] In some embodiments, the first base, the second base, and the first shielding plate are tilted relative to the scintillator, and the first base and the first shielding plate thereon have the same tilt angle.

[0015] In some embodiments, the detector assembly is applied to a computed tomography imaging system, which includes an X-ray source, and the plurality of first shielding plates are arranged toward the X-ray source.

[0016] In some embodiments, a projection of the first shielding plate falls on the first base on which the first shielding plate is located regardless of the angle of the X-ray source relative to the collimator.

[0017] In some embodiments, the collimator is a 3D printed collimator.

[0018] In some embodiments, the width of the first base is a specific size in the range of 0.18 to 0.26 mm, the width of the second base is a specific size in the range of 0.18 to 0.22 mm, and the width of the first shielding plate is a specific size in the range of 0.05 to 0.1 mm.

[0019] According to another aspect of an embodiment of the present application, a detector assembly is provided, wherein the detector assembly includes the collimator described in any one of the aforementioned embodiments.

[0020] According to yet another aspect of the embodiments of the present application, a computed tomography imaging system is provided, wherein the computed tomography imaging system includes the detector assembly described in the aforementioned embodiments.

[0021] One of the beneficial effects of the embodiment of the present application is that: according to the embodiment of the present application, the first shielding plates (such as Z plates) of the collimator of the detector assembly are arranged at intervals, and the width of the first base below the first shielding plate is relatively wide, sufficient to cover the shadow of the first shielding plate, thereby ensuring the operating performance. In addition, between the two first bases is a second base with a narrower width, which can ensure the uniform performance of the pixels when X-rays pass through, thereby helping to obtain higher dose efficiency.

[0022] With reference to the following description and drawings, specific embodiments of the present application are disclosed in detail, indicating the manner in which the principles of the present application can be employed. It should be understood that the embodiments of the present application are not limited in scope thereby. Within the scope of the terms of the appended claims, the embodiments of the present application include many variations, modifications, and equivalents.

[0023] Features described and / or illustrated with respect to one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0024] It should be emphasized that the term "include / comprising" when used herein refers to the presence of features, integers, steps or components, but does not exclude the presence or addition of one or more other features, integers, steps or components. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The elements and features described in one figure or one embodiment of the present application can be combined with the elements and features shown in one or more other figures or embodiments. In addition, in the accompanying drawings, similar reference numerals represent corresponding parts in several figures and can be used to indicate corresponding parts used in more than one embodiment.

[0026] The included drawings are used to provide a further understanding of the embodiments of the present application, constitute a part of the specification, and are used to illustrate the implementation methods of the present application and, together with the text description, explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without inventive work.

[0027] Figure 1 is a schematic diagram of a CT imaging device according to an embodiment of the present application;

[0028] Figure 2 is a schematic diagram of a CT imaging system according to an embodiment of the present application;

[0029] Figure 3 is a schematic diagram of an example of a collimator module according to an embodiment of the present application;

[0030] Figure 4 It is along Figure 3 A partial schematic diagram of the collimator module cut along the AA direction shown;

[0031] Figure 5 It is along Figure 4 The figure shows a schematic diagram of a cross-sectional view of the collimator module. DETAILED DESCRIPTION

[0032] The above and other features of the present application will become apparent through the following description with reference to the accompanying drawings. In the specification and the accompanying drawings, specific embodiments of the present application are disclosed in detail, which show some embodiments in which the principles of the present application can be adopted. It should be understood that the present application is not limited to the described embodiments. On the contrary, the present application includes all modifications, variations and equivalents that fall within the scope of the appended claims.

[0033] In the embodiments of the present application, the terms "first", "second", etc. are used to distinguish different elements from the name, but do not indicate the spatial arrangement or temporal order of these elements, and these elements should not be limited by these terms. The term "and / or" includes any one and all combinations of one or more of the associated listed terms. The terms "comprising", "including", "having", etc. refer to the presence of the stated features, elements, components or components, but do not exclude the presence or addition of one or more other features, elements, components or components.

[0034] In the embodiments of this application, the singular forms "a," "the," etc. may include plural forms and should be broadly understood to mean "a" or "a type" rather than being limited to "one." Furthermore, the term "said" should be understood to include both singular and plural forms, unless the context clearly indicates otherwise. Furthermore, the term "according to" should be understood to mean "at least in part based on...", and the term "based on" should be understood to mean "at least in part based on...", unless the context clearly indicates otherwise.

[0035] Figure 1 FIG. 1 is a schematic diagram of a CT imaging device according to an embodiment of the present application, schematically illustrating the CT imaging device 100. Figure 1 As shown, a CT imaging device 100 includes a scanning gantry 101 and a patient table 102. The scanning gantry 101 has an X-ray source 103 that projects an X-ray beam toward a collimator or detector assembly 104 on opposite sides of the scanning gantry 101. A subject 105 can lie flat on the patient table 102 and move into a scanning gantry opening 106 along with the patient table 102. Medical imaging data of the subject 105 can be obtained through scanning by the X-ray source 103.

[0036] Figure 2 FIG is a schematic diagram of a CT imaging system according to an embodiment of the present application, schematically showing a block diagram of a CT imaging system 200. Figure 2 As shown, the detector assembly 104 includes a plurality of detector units 104 a and a data acquisition system (DAS) 104 b . The plurality of detector units 104 a sense the projected X-rays that pass through the inspection object 105 .

[0037] The DAS 104b converts the collected information into projection data for subsequent processing based on the sensing of the detector unit 104a. During a scan to acquire X-ray projection data, the scanning gantry 101 and the components mounted thereon rotate around the rotation center 101c.

[0038] The rotation of the gantry 101 and the operation of the X-ray source 103 are controlled by a control mechanism 203 of the CT imaging system 200. The control mechanism 203 includes an X-ray controller 203a, which provides power and timing signals to the X-ray source 103, and a gantry motor controller 203b, which controls the rotational speed and position of the gantry 101. An image reconstruction device 204 receives projection data from the DAS 104b and performs image reconstruction. The reconstructed image is transmitted as input to a computer 205, which stores the image in a mass storage device 206.

[0039] The computer 205 also receives commands and scan parameters from an operator via a console 207. The console 207 has some form of operator interface, such as a keyboard, mouse, voice activated controller, or any other suitable input device. An associated display 208 allows the operator to observe the reconstructed image and other data from the computer 205. The commands and parameters provided by the operator are used by the computer 205 to provide control signals and information to the DAS 104b, the x-ray controller 203a, and the scan gantry motor controller 203b. In addition, the computer 205 operates the patient table motor controller 209, which controls the patient table 102 to position the subject 105 and the scan gantry 101. In particular, the patient table 102 moves the subject 105, in whole or in part, through the scan gantry 101. Figure 1 The scanning gantry opening 106 is provided.

[0040] The embodiments of the present application are described below with reference to the accompanying drawings. In the following description, the X direction refers to the lateral direction of the CT imaging device, that is, the left-right direction of the detection object, that is, the channel direction of the detector; the Z direction refers to the longitudinal direction, that is, the direction in which the detection object enters and exits the CT imaging device, that is, the tomographic or slice direction of the CT imaging device; the Y direction refers to the radial direction of the CT imaging device, that is, the direction perpendicular to both the X and Z directions; in addition, unless otherwise specified, "up" and "down" refer to "up" and "down" in the direction of gravity. Figure 1 The X direction, the Y direction, and the Z direction are schematically shown.

[0041] An embodiment of the present application provides a collimator, which is applied to a detector assembly of a CT system. For example, the detector assembly is the CT detector, detector assembly 104, etc. mentioned above. The present application is not limited thereto, and the collimator can also be applied to other detector assemblies in other fields.

[0042] In an embodiment of the present application, the collimator is also referred to as an anti-scatter grid (ASG), and includes a collimator module. The collimator module can be 3D printed, thereby reducing costs, and has the characteristics of strong rigidity, thin wall thickness, high density, high absorption of scattered radiation, and good light shielding. However, the present application is not limited thereto, and the collimator module can also be manufactured by other means, as long as it can absorb and filter X-rays scattered and refracted from CT detection to improve image contrast. In some embodiments, the collimator also includes other components in addition to the collimator module, such as a bracket supporting the collimator module, etc. For details, please refer to the relevant technology.

[0043] Figure 3 is a schematic diagram of an example of a collimator module according to an embodiment of the present application; Figure 4 It is along Figure 3 A partial schematic diagram of the collimator module cut along the AA direction shown; Figure 5 It is along Figure 4 The cross-sectional view of the collimator module is shown, schematically illustrating the basic structure of the collimator module. Figure 5 A scintillator S is also schematically shown.

[0044] like Figures 3 to 5 As shown, the collimator module of an embodiment of the present application includes a plurality of first bases 11 arranged at intervals, a second base 12 located between every two first bases 11, and a plurality of first shielding plates 13 located on the first base 11, wherein the width of the second base 12 is smaller than the width of the first base 11, and the width of the first shielding plate 13 is smaller than the width of the first base 11.

[0045] In the above embodiment, the first shielding plate 13 is, for example, a Z-plate of a collimator module (which is used to separate radiation directed to the detector into Z-direction, slice, or tomographic units, extending parallel to the X-direction). The Z-plates of the collimator module are arranged in intervals, and a first grid (i.e., a first base 11) is provided below the Z-plates. This first grid not only covers the gaps between adjacent scintillators but also covers the shadow of the Z-plate (i.e., the projection of the Z-plate on the scintillator. When the tube is hot or cold, the X-ray emission point will move. When this emission point is not fully aligned with the Z-plate, a shadow is formed on the scintillator, referred to as the Z-plate shadow). This ensures the motion performance of the Z-plate, meaning that no matter how the X-ray emission point moves, the performance of the collimator module is not affected. Furthermore, a second grid (i.e., a second base 12) is provided between each pair of Z-plates. This second grid ensures pixel uniformity when X-rays pass through, thereby contributing to higher dose efficiency.

[0046] In the above embodiment, the width of the first grid (referred to as the first width) is greater than the width of the second grid (referred to as the second width), that is, relative to the second grid, the first grid is a wider grid, and relative to the first grid, the second grid is a narrower grid.

[0047] In the embodiments of this application, Figure 5 As shown, the detector assembly (e.g., a CT detector) further includes a plurality of scintillators S, and the first base 11 and the second base 12 are respectively located above the gap between two adjacent scintillators S. This ensures that X-rays do not fall into the gap between the scintillators S, thereby improving imaging quality.

[0048] In the above embodiment, there are no restrictions on the configuration and structure of the scintillator S, nor on the distance between two adjacent scintillators S (i.e., the width of the gap, referred to as the third width). As long as the first base 11 and the second base 12 can block X-rays from the CT system's tube (X-ray source 103), the distance is sufficient. For example, the first width and the second width are both greater than the third width.

[0049] In some embodiments, as Figure 5 As shown, the first base 11, the second base 12, and the first shielding plate 13 are arranged at an angle relative to the scintillator S. Furthermore, the first base 11 and the first shielding plate 13 located thereon have the same inclination angle. This further prevents X-rays from entering the spaces between the scintillators S. In other words, X-rays that might otherwise reach the spaces between the scintillators S are shielded or absorbed, thereby improving imaging quality.

[0050] In some embodiments, as described above, the detector assembly is used in a computed tomography imaging system, such as Figure 2 The CT system shown in FIG. 1 includes an X-ray source, such as a Figure 2 The X-ray source 103 shown is also called a tube, and the plurality of first shielding plates 13 are arranged toward the X-ray source, thereby further ensuring that the X-rays emitted by the X-ray source will not fall into the gaps between the scintillators S, thereby improving imaging quality.

[0051] In the above embodiment, as the scanning gantry 101 rotates, the scanning assembly 104 also rotates, and the angle of the X-ray source relative to the collimator changes. However, regardless of how the angle of the X-ray source relative to the collimator changes, the projection of the first shielding plate 13 always falls on the first base 11 on which it is located. In other words, regardless of the angle of the X-ray source relative to the collimator, the projection of the first shielding plate 13 always falls on the first base 11 on which it is located. This further ensures that the X-rays emitted by the X-ray source do not fall into the gaps between the scintillators S, thereby improving imaging quality.

[0052] In some embodiments, the width of the first base 11 (first width) can be set to a specific size within the range of 0.18 to 0.26 mm, the width of the second base 12 (second width) can be set to a specific size within the range of 0.18 to 0.26 mm, and the width of the first shielding plate (i.e., (Z plate)) is a specific size within the range of 0.05 to 0.1 mm, thereby ensuring imaging quality. For example, the width of the first base is 0.23 mm, the width of the second base is 0.2 mm, and the width of the first shielding plate is 0.08 mm.

[0053] It is worth noting that the above description only describes the components or modules related to the present application, but the present application is not limited thereto. The collimator of the embodiment of the present application may also include other components or modules, and various implementations that can be conceived by those skilled in the art based on the above disclosure are included in the scope of protection of the present application.

[0054] According to the above embodiment, the first shielding plates (e.g., Z plates) of the collimator of the detector assembly are arranged at intervals, and the width of the first base below the first shielding plate is relatively wide, sufficient to cover the shadow of the first shielding plate, thereby ensuring operational performance. In addition, between the two first bases is a second base with a narrower width, thereby ensuring uniform performance of pixels when X-rays pass through, thereby contributing to obtaining higher dose efficiency.

[0055] The present application also provides a detector assembly. The detector assembly includes the collimator of the above embodiment, for example Figure 2 The detector assembly 104 shown in FIG. 1 may also be referred to as a CT detector. Figure 2 For details, please refer to the relevant technology and will not go into details here.

[0056] It can be seen from the above embodiments that the detector assembly of the embodiment of the present application includes the collimator of the aforementioned embodiment, and the first shielding plates (such as Z plates) of the collimator are arranged at intervals. The width of the first base below the first shielding plate is relatively wide, which is sufficient to cover the shadow of the first shielding plate, thereby ensuring the operating performance. In addition, between the two first bases is a second base with a narrower width, which can ensure the uniform performance of the pixels when X-rays pass through, thereby helping to obtain higher dose efficiency.

[0057] The present application also provides a computerized tomography imaging system. The computerized tomography imaging system includes the detector assembly of the above embodiment, for example, Figure 2 The CT imaging system shown in FIG. 3 may refer to FIG. 3 for other configurations and functions of the CT imaging system. Figure 2 For details, please refer to the relevant technology and will not go into details here.

[0058] It can be seen from the above embodiments that the computed tomography imaging system of the embodiment of the present application adopts the detector assembly of the aforementioned embodiment, which includes the collimator of the aforementioned embodiment, and the first shielding plates (such as Z plates) of the collimator are arranged at intervals. The width of the first base below the first shielding plate is relatively wide, sufficient to cover the shadow of the first shielding plate, thereby ensuring the operating performance. In addition, between the two first bases is a second base with a narrower width, which can ensure the uniform performance of the pixels when X-rays pass through, thereby helping to obtain higher dose efficiency.

[0059] It is worth noting that the above only describes the components or modules related to the present application, but the present application is not limited thereto. The lifting bed of the embodiment of the present application may also include other components or modules. For the specific contents of these components or modules, reference may be made to the relevant art.

Claims

1. A collimator, applied to a detector assembly, comprising a collimator module, characterized in that: The collimator module comprises: a plurality of first bases arranged at intervals; a second base located between every two first bases; and a plurality of first shielding plates located on the first base; The width of the second base is smaller than that of the first base, and the width of the first shielding plate is smaller than that of the first base.

2. The collimator according to claim 1, wherein The detector assembly includes a plurality of scintillators, and the first base and the second base are respectively located above the gap between every two scintillators.

3. The collimator according to claim 2, characterized in that The first base, the second base and the first shielding plate are arranged obliquely relative to the scintillator, and the first base and the first shielding plate located thereon have the same inclination angle.

4. The collimator according to claim 1, wherein: The detector assembly is applied to a computer tomography imaging system. The computer tomography imaging system includes an X-ray source. The plurality of first shielding plates are arranged toward the X-ray source.

5. The collimator according to claim 4, characterized in that The projection of the first shielding plate falls on the first base where the first shielding plate is located regardless of the angle of the X-ray source relative to the collimator.

6. The collimator according to claim 1, characterized in that The collimator is a 3D printed collimator.

7. The collimator according to any one of claims 1 to 6, characterized in that: The width of the first base is 0.23 mm, the width of the second base is 0.2 mm, and the width of the first shielding plate is 0.08 mm.

8. A detector assembly, characterized in that: The detector assembly comprises the collimator according to any one of claims 1 to 7.

9. A computer tomography imaging system, characterized in that: The computed tomography imaging system comprises the detector assembly of claim 8.

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