CN111227857A - Detector module, detector and CT equipment - Google Patents

Abstract

The application discloses detector module, detector and CT equipment. The detector module is used for detecting rays emitted by an X-ray source of a CT host computer after being attenuated by a scanned object and comprises a support and a plurality of detector sub-modules arranged on the support. Each detector sub-module includes a top surface to receive radiation, and the top surfaces of the plurality of detector sub-modules are arranged along a Z-direction arc or a straight line of the CT rotation system. The top surfaces of the detector sub-modules form a receiving field corresponding to the irradiation field of the X-ray source in a YZ plane of the CT rotating system, the receiving field is asymmetric relative to a focus reference plane of the X-ray source, the focus reference plane passes through the focus center of the X-ray source and is parallel to an XY plane of the CT rotating system. The detector module can reduce the performance parameter requirement of an X-ray source and the manufacturing cost and difficulty of a CT device with large Z-direction coverage (such as 512 layers).

Description

Detector modules, detectors and CT equipment

technical field

The present application relates to the technical field of computed tomography, and in particular, to a detector module, a detector, and a CT apparatus.

Background technique

With the development of CT (Computed Tomography, Computed Tomography) technology, the coverage of a single scan of the human body is required to be larger and larger. Accordingly, the number of layers of the detector is increasing, and more and more layers need to be installed on the housing. At the same time of the detector sub-module, the irradiation field of the X-ray source as the detector signal source is also required to be larger and larger. In this way, an X-ray source with a larger target angle has to be used to achieve a large Z-direction of the CT rotation system. Imaging of coverage areas, however, ultimately makes it difficult and expensive to manufacture CT devices with large coverage areas in the Z direction.

SUMMARY OF THE INVENTION

To overcome some or all of the problems in the related art, the present application provides a detector module. The detector module is used to detect the attenuated rays of the scanned object emitted by the X-ray source of the CT host, and includes a bracket and a plurality of detector sub-modules mounted on the bracket, wherein each detector sub-module includes a receiving ray The top surfaces of the plurality of detector sub-modules are arranged along the Z-direction arc or straight line of the CT rotation system of the CT host; The YZ plane constitutes a receptive field corresponding to the irradiation field of the X-ray source, the receptive field being asymmetric with respect to the focal reference plane of the X-ray source, the focal reference plane passing through the focal center of the X-ray source and Parallel to the XY plane of the CT rotation system.

Optionally, the top surfaces of all detector sub-modules are distributed on the arc of the same target circle with the focal center of the X-ray source as the center, or the top surfaces of a plurality of the detector sub-modules are distributed. On the arc of the target circle with unequal radii with the focal center of the X-ray source as the center.

Optionally, the radius of the target circle tangent to the top surfaces of the detector submodules on both sides of the focus reference plane is Rc, and the top surfaces of the detector submodules far from the focus reference plane are tangent to each other. The radius of the target circle is Rf, Rc<Rf.

Optionally, the sum of the widths of the top surfaces of the detector submodules on one side of the focus reference plane along the Z direction is greater than the top surface of the detector submodules on the other side of the focus reference plane along the Z direction. The sum of the widths is such that the receptive field is asymmetric with respect to the focal reference plane.

Optionally, the X-ray source includes a target disk, and a receptive field close to the target disk is smaller than a receptive field farther from the target disk.

Optionally, the widths of the top surfaces of the plurality of detector sub-modules in the Z direction are equal or unequal.

Optionally, the width in the X direction of the top surface of the detector submodule close to the focal reference plane is greater than the width in the X direction of the top surface of the detector submodule far from the focal reference plane so that the top surface is in the X direction. The width in the X direction presents a decreasing trend along the Z direction from the focal reference plane in the direction away from the focal reference plane.

Optionally, the width in the X direction of the top surface of the detector submodule close to the focus reference plane is greater than the width in the X direction of the top surface of the detector submodule far from the focus reference plane. The top surfaces of the detector submodules with the same distance from the reference surface have the same width in the X direction, or the top surfaces of the detector submodules within the preset range outside the preset distance from the focus reference surface are in the X direction. The widths are equal; or, a plurality of detector sub-modules within the preset range beyond the preset distance from the focus reference surface are rectangular parallelepipeds, and each detector sub-module within the second preset range has The top surfaces are of equal width in the X direction, equal width in the Z direction, and equal height in the Y direction for each detector submodule.

Optionally, among the plurality of detector sub-modules, the shape of the top surface of at least one detector sub-module is a trapezoid.

Optionally, the trapezoid is an isosceles trapezoid.

Optionally, each of the detector sub-modules includes a scintillator pixel array, and each scintillator pixel of the array includes a top surface that receives the rays; the shape of the top surface is a trapezoidal scintillator pixel of the detector sub-module. The array includes edge scintillator pixels located along the Z direction and on both sides of the array, and the top surface of each edge scintillator pixel is trapezoidal in shape.

Optionally, the top surfaces of all scintillator pixels of the scintillator pixel array are trapezoidal; alternatively, the scintillator pixel array includes intermediate scintillator pixels located between edge scintillator pixels, the edge scintillator pixels The top surface of the middle scintillator pixel is trapezoidal, and the top surface of the middle scintillator pixel is rectangular.

Optionally, each of the detector submodules includes a bottom surface opposite the top surface and side surfaces connected to the top and bottom surfaces, the side surfaces being perpendicular to the XZ plane of the CT rotation system.

The present application also discloses a detector, which includes a housing and a plurality of detector modules of any of the foregoing, wherein the plurality of detector modules are arranged side by side on the housing along the X-direction of the CT rotation system.

The present application also discloses a CT device, which includes a scanning gantry, an X-ray source and any one of the foregoing detectors, wherein the scanning gantry includes an opening for receiving a scanned object; the X-ray source is used for transmitting The scanning object emits rays; the detector and the X-ray source are arranged on opposite sides of the opening, and are used for receiving the rays attenuated by the scanning object and converting the rays into electrical signals.

The technical solutions provided by the embodiments of the present application have at least the following beneficial effects:

1. Since the top surfaces of the plurality of detector sub-modules form a receptive field corresponding to the irradiation field of the X-ray source on the YZ plane of the CT rotation system, the receptive field is relative to the focal reference plane of the X-ray source. Asymmetric, in this way, it can better meet the irradiation characteristics of the X-ray source and make full use of the rays of the X-ray source, reducing the performance parameters of the X-ray source (such as the tube that emits X-rays) and the Z-direction large coverage ( For example, the manufacturing difficulty and cost of CT equipment with 512 layers).

2. When the receptive field formed by the top surface of the detector sub-module is asymmetrical with respect to the focal reference plane in the Z-direction, the X-direction gap between adjacent modules at different positions in the Z-direction will be larger than that in the Z-direction symmetrical state. The more inhomogeneous, the greater the deviation. Distributing the top surfaces of a plurality of the detector sub-modules on the arc of the target circle with the focal center of the X-ray source as the center and unequal radii can make the adjacent detector modules in different positions in the Z direction. The X-axis gap is equal or the deviation value is as small as possible, which can ensure or even optimize the image quality while reducing the cost of the X-ray source. In addition, when the electrical signal generated by the detector module is processed in the later stage, the correction of the data is relatively small. Easy, which simplifies the processing of data.

3. Since the radius of the target circle tangent to the top surfaces of the detector submodules on both sides of the focal reference plane is Rc, the target circle tangent to the top surfaces of the detector submodules far from the focal reference plane The radius is Rf, Rc<Rf, so the advantage is that the X-direction gaps of adjacent detector modules at different positions in the Z-direction can be made equal or the deviation value is as small as possible, and the electrical signals generated by the detector modules can be processed later. During processing, it is easier to modify the data, which can simplify the processing of the data.

4. Since the width of the top surface of the detector submodule close to the focal reference plane in the X direction is greater than the width of the top surface of the detector submodule far from the focal reference plane in the X direction, the top surface is in the X direction. The width of the focal reference plane shows a decreasing trend from the focal reference plane to the direction away from the focal reference plane in the Z direction. In this way, it is ensured that the gaps in the X direction of the adjacent detector modules at different positions in the Z direction are equal or the deviation value is as far as possible. Small, increase the physical area of the CT detector to collect images and simplify data processing; moreover, it can also reduce the performance parameters of the X-ray source (such as the tube that emits X-rays) and the Z-direction large coverage (such as 512 layers) The manufacturing difficulty and cost of CT equipment.

5. Since the shape of the plurality of detector sub-modules in the second preset range beyond the second preset distance from the focus reference surface is a cuboid, the top of each detector sub-module in the second preset range is The width of the surface in the X direction is equal, the width in the Z direction is equal, and the height of each detector sub-module in the Y direction is equal, thus reducing the types of detector sub-modules and achieving the purpose of cost optimization.

6. In the detector sub-module whose top surface is trapezoidal, the top surface of the edge scintillator pixel is trapezoidal, so that the X-ray receiving area can be maximized, and the image quality can be finally improved. When the shape of the top surface of the edge scintillator pixel is a trapezoid and the top surface of the middle scintillator pixel is a rectangle, the X-ray receiving area can be more maximized, and the image quality is finally improved. In the case where the top surfaces of all scintillator pixels are trapezoidal, the X-ray receiving area can also be maximized, and the image quality can be finally improved.

7. When designing and manufacturing a detector with a large coverage in the Z direction, the receptive field formed by the top surface of the detector sub-module is asymmetric in the Z direction, and the X-direction gap between adjacent modules in different positions in the Z direction will be It is more inhomogeneous and the deviation is larger than in the Z-symmetric state. The trapezoidal shape of the top surface of the at least one detector sub-module can solve this problem, and can also ensure or even optimize image quality while reducing the cost of the X-ray source.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not limiting of the present application.

Description of drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and together with the description serve to explain the principles of the application.

1 is a schematic diagram of the state of X-rays emitted by a bulb;

Fig. 2 is a kind of structural representation of CT equipment;

3 is a schematic diagram of a receiving field corresponding to an irradiation field formed by a detector module of the present application;

4 is a schematic structural diagram of a detector formed by the detector module of the present application;

Fig. 5 is the structural representation of the first detector module;

6 is a projection view of the detector module shown in FIG. 5 on the YZ plane of the CT rotation system;

Fig. 7 is the structural representation of the second detector module;

8 is a projection view of the detector module shown in FIG. 7 on the YZ plane of the CT rotation system;

9 is a projection view of the third detector module on the XZ plane of the CT rotation system;

Figure 10 is a projection view of the fourth detector module on the XZ plane of the CT rotation system;

11 is a projection view of the fifth detector module on the XZ plane of the CT rotation system;

Figure 12 is a projection view of the sixth detector module on the XZ plane of the CT rotation system;

13 is a schematic diagram of a scintillator pixel array of a trapezoidal detector sub-module;

14 is a schematic diagram of a scintillator pixel array of another trapezoidal detector sub-module;

FIG. 15 is a schematic diagram of another asymmetric distribution of receptive fields of a detector module;

FIG. 16 is a projection view of the seventh detector module on the YZ plane.

Detailed ways

Exemplary embodiments will be described in detail herein, examples of which are illustrated in the accompanying drawings. Where the following description refers to the drawings, the same numerals in different drawings refer to the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments are not intended to represent all implementations consistent with this application. Rather, they are merely examples of apparatus and methods consistent with some aspects of the present application as recited in the appended claims.

The terms used in this application are for the purpose of describing particular embodiments only and are not intended to limit the application. As used in this application and the appended claims, the singular forms "a," "the," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise.

It should be understood that "first", "second" and similar words used in the description and claims of the present application do not denote any order, quantity or importance, but are only used to distinguish different components. Likewise, "a" or "an" and the like do not denote a quantitative limitation, but rather denote the presence of at least one; "a plurality" denotes a quantity of two or more. Unless otherwise indicated, terms such as "front," "rear," "lower," and/or "upper" are for convenience of description and are not limited to one location or one spatial orientation. Words like "include" or "include" mean that the elements or items appearing before "including" or "including" cover the elements or items listed after "including" or "including" and their equivalents, and do not exclude other elements or objects.

The exemplary embodiments of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments and features in the embodiments may complement each other or be combined with each other without conflict.

Referring to FIG. 1, an X-ray tube (or called a tube) includes a target disk 1, which has a focal point F, and the focal point F has a focal center. For example, when the focal point F is square, the focal center is the geometric center of the square focal point . In order to solve the problem that the X-ray tube with a larger target angle makes it difficult and expensive to manufacture CT equipment with a large Z-direction coverage, the inventor of the present application found that the detector of the existing CT equipment can use the X-ray irradiation The field is symmetrical with respect to the focal reference plane L of the X-ray tube, as shown in the fan angle A and the fan angle B in Figure 1, in order to obtain a larger irradiation field (that is, to make the fan angle A and the fan angle B larger ), an X-ray tube with a larger target angle is required, which makes the CT equipment difficult to manufacture and expensive. In order to solve this problem and meet the requirement of a large irradiation field, the inventor thought that if the C area can be used, the irradiation field can be increased, and accordingly, the requirements on the performance parameters of the X-ray tube are reduced (for example, the X-ray ball The target angle of the tube does not need to be too large), thereby reducing the manufacturing difficulty and cost of CT equipment with large coverage in the Z direction. Therefore, the inventors of the present application developed a detector module, a detector, and a CT apparatus. In order to facilitate a clearer understanding of this application, the relevant contents of the CT equipment are first described as follows:

Please refer to FIG. 2 . The CT device shown in FIG. 2 is a medical device. However, the skilled person can understand that the CT device may be a device used for security inspection (for example, a security inspection machine). Since these equipments all include detectors, only a CT machine used for medical treatment is used as an example to describe the configuration as follows: the medical equipment includes a scanning gantry 10 , an X-ray source 20 , a detector 30 and a carrying table 40 . The gantry 10 is formed with an opening 11 for receiving the scanned object 50 . The illustrated coordinate system is the coordinate system of the CT rotation system rotatable with respect to the gantry 10 . The CT rotation system includes at least the X-ray source 20 and the detector 30 . As shown in the figure, the coordinate system includes an X axis, a Y axis and a Z axis that are perpendicular to each other. Correspondingly, in the subsequent description, the Z direction is the direction along the Z axis, and the X direction is the direction along the X axis. The Z axis is the rotation axis of the CT rotation system, which is parallel to the coronal plane of the scanning object 50 (patient in the medical field), and defines the slice direction of the CT device. The X-axis and Y-axis define a plane perpendicular to the Z-axis, which is generally along the channel direction of the detector 30 . The X-ray source 20 and detector 30 rotate circumferentially about the Z-axis as a group.

The scanning object 50 is placed on the carrying table 40 and can be located in the opening 11 together with the carrying table 40 . In the field of security inspection, the scanning object is luggage or a human body, which can be conveyed by the conveying device to pass through the opening 11 . The X-ray source 20 and the detector 30 are arranged on opposite sides of the opening 11 . The X-ray source 20 is used to emit a fan-shaped or cone-shaped beam of rays to the scanned object 50 . The X-ray source 20 projects an X-ray beam from its focal point F to the scanning object 50 .

Referring to FIGS. 4 to 12 , the detector 30 of the present application is used to detect rays attenuated by the scanned object 50 emitted by the X-ray source 20 of the CT host, and includes a plurality of detector modules 3 (as shown in the dashed box in FIG. 4 ) is a detector module 3) and the housing 302. A plurality of detector modules 3 are arranged side by side on the housing 302 along the X-direction of the CT rotation system.

Please refer to FIGS. 3 , 5 to 8 in conjunction with FIG. 4 , each detector module 3 includes a bracket 301 and a plurality of detector sub-modules 31a1 to 31a8 mounted on the bracket 301 . Although 8 detector sub-modules are shown, the number of detector sub-modules is not limited to this. Each of the detector sub-modules 31a1 to 31a8 includes a top surface 311 for receiving rays. As shown in FIGS. 5 to 8 , the top surfaces 311 of the plurality of detector sub-modules 31a1 to 31a8 are along the coordinate system of the CT rotation system. (hereinafter referred to as CT rotation system for short) is arranged in an arc in the Z direction. In various embodiments of the present application, the arc arrangement refers to the circle between the top surface of the detector sub-module and the target circle with the focal center as the center of the circle. The arcs are tangent. Those skilled in the art can understand that, in other embodiments, the top surfaces 311 may also be aligned along the Z-direction. In various embodiments of the present application, the linear arrangement means that the top surfaces of the detector submodules are coplanar or that the top surfaces of the detector submodules on the bracket are respectively located on several different planes, and these planes are parallel to each other, and the sides of the planes are parallel to each other. See, these planes form a staircase. The top surfaces 311 of the plurality of detector sub-modules 31a1 to 31a8 form a receiving field 32 corresponding to the irradiation field of the X-ray source on the YZ plane of the CT rotation system, and the receiving field 32 is opposite to the X-ray source 20 . The focal reference plane L (which can also be considered to be the target disk 1) is asymmetrical. As shown in FIG. 3 , taking the focal reference plane L as a reference, the receiving field 32 includes a left receiving field 321 and a right receiving field 322 , and the left receiving field 321 and the right receiving field 322 are not relative to the focal reference plane L. symmetry. The receptive field 322 close to the target disk 1 is smaller than the receptive field 321 away from the target disk 1 . By arranging the receptive field 32 asymmetrically with respect to the focal reference plane L (the focal reference plane L passing through the focal center of the X-ray source and parallel to the XY plane of the CT rotation system), the detector sub-surface is made The distribution of the top surface of the module is more in line with the irradiation characteristics of the X-ray source, making full use of the X-rays in the C area, and can not use the X-ray source with a large target angle, reducing the performance parameters of the X-ray source and the large coverage in the Z direction. Difficulty and cost of manufacture of CT devices of a range (eg 512 slices).

Please continue to refer to FIG. 5 and FIG. 6 , in one embodiment, the top surfaces 311 of all detector sub-modules 31a1 to 31a8 are distributed on the same target circle centered on the focal center of the focal point F of the X-ray source on the arc. 5 and 6 illustrate eight detector submodules 31a1 to 31a8, and those skilled in the art can understand that, in any implementation manner, the specific number of detector submodules is not limited thereto, and depends on the number of layers of detectors. As shown in FIGS. 5 and 6 , the widths of the top surfaces 311 of each detector sub-module 31a1 to 31a8 in the Z direction are equal, so that, taking the focus reference plane L as the dividing point, the number of detector sub-modules on the left (( 5, respectively 31a1, 31a2, 31a3, 31a4 and 31a5) than the number of detector sub-modules on the right (3, respectively 31a6, 31a7, 31a8). In FIG. 6 , in order to specifically illustrate the asymmetry, the focal reference plane L is extended toward the detector sub-module. Through such a design, the sum of the widths of the detector submodules on one side of the focal reference plane L along the Z direction is greater than the sum of the widths of the detector submodules on the other side of the focal reference plane L along the Z direction and so that the receptive field is asymmetric with respect to the focal reference plane L of the X-ray source.

Referring to FIG. 7 and FIG. 8 , in an embodiment, the top surfaces 311 of the plurality of detector sub-modules 31a1 to 31a8 are distributed on targets with unequal radii with the focus F of the X-ray source 20 as the center of the circle on the arc of the circle. Figures 7 and 8 illustrate two radii R1 and R2, the top surface 311 of the first to third detector submodules 31a1 to 31a3 and the seventh detector submodule 31a7 and the eighth detector submodule The top surface of 31a8 is distributed on and tangent to a target circle of radius R2, and the top surfaces 311 of the fourth to sixth detector sub-modules 31a4 to 31a6 are distributed on and tangent to the target circle of radius R1. The circles are tangent, where R1<R2. In FIG. 8 , the width of the top surface of each detector sub-module along the Z direction is equal, and the number of detector sub-modules on the left side of the focal reference plane L is more than the number of detector sub-modules on the right side (the left side includes at least 4 detector sub-modules). The detector submodules 31a1 to 31a4, the right side includes at least three detector submodules 31a6 to 31a8), so that the sum of the widths of the detector submodules on the side of the focal reference plane L along the Z direction is greater than the The sum of the widths of the detector sub-modules on the other side of the focal reference plane along the Z direction is such that the receptive field is asymmetric with respect to the focal reference plane L of the X-ray source.

When designing and manufacturing a detector with a large coverage in the Z-direction, when the top surface of the detector module is in the Z-direction asymmetric state, the X-direction gap between adjacent modules at different positions in the Z-direction will be larger than that in the Z-direction symmetrical state. The more inhomogeneous, the greater the deviation. The top surfaces of the plurality of detector sub-modules are distributed on the arc of the target circle with the focal center of the X-ray source as the center and with unequal radii, so that the X-direction of adjacent detector modules at different positions in the Z-direction The gap is equal or the deviation value is as small as possible, which can ensure or even optimize the image quality while reducing the cost of the X-ray source. In addition, when the electrical signal generated by the detector module is processed in the later stage, it is easier to correct the data. Simplify the processing of data.

Please continue to refer to FIG. 7 and FIG. 8. In one embodiment, the radius of the target circle tangent to the top surfaces of the detector sub-modules on both sides of the focal reference plane L is Rc, and the radius of the target circle far from the focal reference plane is Rc. The radius of the target circle tangent to the top surface of the detector sub-module is Rf, where Rc<Rf. In this embodiment, approach and distance are relative concepts, and there are only two types of target circles as shown in FIG. 8 . In this case, Rc=R1 and Rf=R2. Because only two kinds of radii are shown in FIG. 7 and FIG. 8 , according to the actual situation, three or more radius values may be set, and these radius values may be completely unequal or not completely equal. The description of the three radius values is as follows, and the other radius values are deduced by analogy. In order to illustrate the case of a target circle with three radius values, the case is illustrated by using Figure 7 and Figure 8 as examples to illustrate the situation as follows:

8, from left to right, the first and second detector sub-modules 31a1 and 31a2 are compared with the third detector sub-module 31a3, the first and second detector sub-modules 31a1 and 31a2 are the detector submodules far from the focus reference plane L, the radius of the tangent target circle is R2, and the third detector submodule 31a3 is the detector submodule close to the focus reference plane L, and the tangent target circle has a radius of R2. The radii are respectively Rc, which are shown as dashed lines in FIG. 8 because the description is borrowed from FIG. 8; compared with the fourth detector submodule 31a4, the third detector submodule 31a4 is For the detector submodule close to the focal reference plane L, the radius of the target circle tangent to the fourth detector submodule 31a4 is R1. According to the above Rc<Rf, R1<Rc<R2 can be obtained.

Since the Rc<Rf, in this way, it is ensured that the X-direction gaps of adjacent detector modules 3 at different positions in the Z-direction are equal or the deviation value is as small as possible, so as to obtain better image quality.

The inventors of the present application found that: in order to ensure consistent detector characteristics, the detector sub-modules on the detector module are usually arranged along a circular arc in the Z direction, so that the distance from the focus to the detector is consistent, and the radiation attenuation characteristics are consistent, which is convenient for subsequent images. deal with. Since the X and Z directions are arranged along arcs concentric with the focal point, the top surface of the detector sub-module is equivalent to being arranged on a spherical surface. It can be seen from the spherical cutting that if the detector sub-module of square scintillator pixels is used to spell out A spherical surface, then the scintillator pixels of each detector sub-module need to be rectangles of different sizes to ensure the same gap at the splicing. At least the width of the detector sub-module along the Z direction is getting smaller and smaller. If it converges to the rotating shaft , theoretically the width of the detector submodule will be zero. In fact, this ideal detector sub-module is difficult to manufacture. For the convenience of manufacturing, the same square or rectangular detector sub-module is usually used in the same CT system. For the special case of rectangle, the principle is similar and will not be repeated. If the rectangular detection sub-modules of the same size are used, in order to ensure that the detector sub-modules located at the edge do not interfere, there will be a large gap at the detector sub-module located in the middle during splicing, especially as the number of layers of CT equipment increases. , the more detector modules are spliced in the Z direction, the larger the gap reserved for the detector sub-module in the middle, the larger the gap between the adjacent detector modules in the X direction in the entire Z direction, and the collected data will affect the image. quality.

In order to solve the above problems, the present application discloses a detector module. Please refer to FIG. 9 to FIG. 12 , it should be noted that FIG. 9 to FIG. 12 are only to highlight the technical means that the top surface 311 of the detector sub-module is designed as a trapezoid. Therefore, each of the drawings presents the diagrams shown in FIGS. 9 to 12 . The state shown, the skilled person can understand that it does not represent the actual size of the detector sub-module and its proportional relationship with other detector sub-modules. Each detector sub-module includes a top surface 311 for receiving the rays emitted by the X-ray source 20 , and the width of the top surface 311 of the detector sub-module close to the focal reference plane L in the X direction is greater than that far from the focal reference plane L The width of the top surface 311 of the detector submodule in the X direction is such that the width of the top surface of each detector submodule in the X direction is away from the focal reference plane in the Z direction away from the focal reference plane (such as the edge of the detector submodule). ) shows a decreasing trend. In this way, this method is combined with the asymmetric method of the receptive field relative to the focal reference plane, which not only ensures that the X-direction gaps of adjacent detector modules at different positions in the Z-direction are equal or the deviation value is as small as possible, so that the , to achieve a CT detector with a large coverage area in the Z direction (such as 512 layers), increase the physical area of the CT detector to collect images, simplify data processing, and improve image quality; The performance parameter requirements of the tube) and the manufacturing difficulty and cost of CT equipment with a large coverage area in the Z direction (such as 512 layers). For example, in FIG. 4 , the X direction is the row, the Z direction is the column, and one column is a detector module 3 shown in the dotted box in FIG. 4 . The X-direction deviation of the adjacent X detector sub-module is smaller as follows: the deviation of the detector sub-module in the first column and the first row and the detector sub-module in the second column and the first row in the X direction is recorded as A1, the first column is the second The deviation of the detector submodule of the row and the detector submodule of the second column and the second row in the X direction is denoted as A2 and the detector submodule of the first column and the third row and the detector submodule of the second column and the third row. The deviation in the X direction is recorded as A3. The deviation is that the deviation of the A1, A2, and A3 relative to the preset value is as small as possible, which means that the difference from the preset value is within a certain range (the deviation value can also be zero if required).

The above-mentioned decreasing trend will be described in detail below: In FIGS. 9 to 12 , the focus reference plane L is marked. The width of the top surface 311 of the detector submodule close to the focal reference plane in the X direction is greater than the width of the top surface 311 of the detector submodule farther away from the focal reference plane in the X direction so that the top surface 311 is wider in the X direction. The decreasing trend of the width from the focal reference plane to the direction away from the focal reference plane along the Z direction includes the following two situations:

1. The width of the top surface 311 of the detector sub-module close to the focal reference plane L in the X direction is greater than the width of the top surface 311 of the detector sub-module far from the focal reference plane L in the X direction, and the distance from the focal reference plane L is equal. The top surfaces 311 of the detector submodules are of equal width in the X direction. For example, in FIG. 9 , the first to third detector sub-modules 31a1 to 31a3 are gradually approaching the focus reference plane L, and the corresponding width of the top surface thereof is L1<L2<L3, which is equal to the distance from the focus reference plane L. The widths of the top surfaces 311 of the detector sub-modules 31a3 and 31a8 in the X direction are equal, ie L3=L8. Similarly, in FIG. 10 , the widths of the top surfaces 311 of the first to fourth detector submodules 31a1 to 31a4 in the X direction are L1<L2<L3<L4 and the fourth detector submodules 31a4 and the seventh detector submodules 31a4 and the seventh The widths of the top surfaces of the detector submodules 31a7 in the X direction L4=L7; in FIG. 11 , the widths of the top surfaces of the first to fourth detector submodules 31a1 to 31a4 in the X direction L1<L2<L3< The width L3=L8 of the top surfaces of L4 and the third detector sub-module 31a3 and the eighth detector sub-module 31a8 in the X direction.

2) The top surfaces of the multiple detector sub-modules in the preset range beyond the preset distance from the focus reference surface are equal in width in the X direction, and the preset distance and preset range can be determined according to the actual situation, as shown in the figure. 11, the preset distance is 0 detector sub-modules, and the preset range is 2 detector sub-modules, then, the top surfaces of the four detector sub-modules 31a4, 31a5, 31a6, 31a7 near the focus reference plane L The width in the X direction is equal, both are L4. For another example, in FIG. 12 , the preset distance is one detector sub-module and the preset range is two detector sub-modules, then the third to fourth detector sub-modules 31a3 and 31a4 and the seventh and fourth detector sub-modules The respective top surfaces of the eight detector sub-modules 31a7 and 31a8 have the same width in the X direction, ie, L3=L4=L7=L8.

Please continue to refer to FIGS. 9 to 12 in conjunction with FIGS. 5 to 8 , in one embodiment, each of the detector sub-modules includes a bottom surface opposite to the top surface 311 and a bottom surface connected to the top surface and The side surface of the bottom surface, the shape of the top surface of at least one detector sub-module is a trapezoid, and the skilled person can understand that in other embodiments, the side surface thereof is perpendicular to the XZ plane of the CT rotation system (which can be understood as: The shape of the detector sub-module is a right quadrangular prism with a trapezoidal top surface and a trapezoidal bottom surface. For the convenience of description, the detector module with a trapezoidal top surface is called a trapezoidal detector sub-module (including a trapezoidal top surface and vertical sides). The detector submodules on the XZ plane). As shown in Figure 9, along the Z direction, the eight detector submodules 31a1, 31a2, 31a3, 31a4, 31a5, 31a6, 31a7 and 31a8 are all trapezoidal detector submodules; As shown in FIG. 10 , the first detector submodule 31a1 is a trapezoidal detector submodule; as shown in FIG. 11 , the first to third detector submodules 31a1 to 31a3 and the eighth detector submodule 31a8 are trapezoidal Detector sub-module. The skilled person can understand that the trapezoid includes an isosceles trapezoid, a right-angled trapezoid or other shapes. Preferably, the trapezoid is an isosceles trapezoid, which is convenient for the manufacture of detectors and CT equipment and can make the The deviation value of the X-direction gap between adjacent detector modules at different positions in the Z-direction is as small as possible to improve the image quality, because when designing and manufacturing a detector with a large coverage in the Z-direction, the top surface of the detector sub-module constitutes the receiving area. In the state of Z-direction asymmetry, the X-direction gap between adjacent modules at different positions in Z-direction will be more inhomogeneous and larger than in Z-direction symmetry state. The top surface of the aforementioned detector sub-module adopts a trapezoidal design , which can solve this problem; moreover, it can ensure or even optimize the image quality while reducing the cost of the X-ray source.

Please continue to refer to FIG. 9 to FIG. 12 , in one embodiment, among the plurality of detector sub-modules, the top surface of at least one detector sub-module has a rectangular shape (a detector whose top surface is a rectangle The submodule is called the rectangle detector submodule). The skilled person can understand that the width of the top surface of the detector sub-module in the X direction gradually decreases from the focal reference plane along the Z direction of the CT rotation system, which can be realized by the combination of the trapezoidal detector sub-module and the rectangular detector sub-module. As shown in Fig. 10 to Fig. 12; it can also be all realized by trapezoidal detector sub-modules, as shown in Fig. 9; of course, based on the second to eighth detector sub-modules 31a2 to 31a8 in Fig. 10 and Fig. 12 And the idea that the second to seventh detector sub-modules 31a2 to 32a7 in FIG. 11 can be designed as rectangular detector sub-modules, and the gradual reduction of the width in the X direction can also be realized by the rectangular detector sub-modules. .

Since the overall trend is to decrease in the Z direction, and the upper base of the trapezoid is parallel to the lower base and in general, the length of the upper base is smaller than the length of the lower base, therefore, for the trapezoidal detector submodule, the top surface The width in the X direction can be considered as one of the lower base or the upper base. In the embodiments of the present application, for the convenience of description, the length of the upper base represents the width of the top surface of the trapezoidal detector sub-module in the X direction; Detector sub-module, its width in X direction is its side length.

Please refer to FIG. 11 and FIG. 12 , in one embodiment, the shape of a plurality of detector sub-modules within a preset range beyond the preset distance from the focal reference plane is a cuboid, and a cube is a special case of a cuboid, The top surfaces of each detector submodule within the preset range are equal in width in the X direction, equal in width in the Z direction, and each detector submodule has an equal height in the Y direction (that is, within the preset range The detector sub-modules have the same length, width and height). For example, in FIG. 11 , the preset distance is 0 detector sub-modules, and the preset range is 2 detector sub-modules. In this way, the top of the fourth to seventh detector sub-modules 31a4, 31a5, 31a6 and 31a7 are respectively The width of the surface in the X direction is equal, the width in the Z direction is the same, and the height of the detector sub-modules in the Y direction is the same, so that the length, width and height of each detector sub-module are equal. For another example, in Figure 12, The preset distance is 1 detector submodule, the preset range is 2 detector submodules, the third detector submodule 31a3, the fourth detector submodule 31a4, the seventh detector submodule 31a7 and the third detector submodule 31a4. The respective top surfaces of the eight detector submodules 31a8 have the same width in the X direction, the same width in the Z direction, and the same height in the Y direction of the detector submodules. high equal. This implementation can reduce the types of sub-modules and achieve the purpose of cost optimization.

Please continue to refer to FIG. 9 to FIG. 12. In FIG. 9 and FIG. 12, the trapezoidal detector sub-module is located at one end or both ends of the entire detector module, but the skilled person can understand that in some embodiments, the The trapezoidal detector sub-module may also be located at other positions of the entire detector module, as long as the width of the top surface of the detector sub-module in the X-direction shows the decreasing trend.

Please refer to FIGS. 13 and 14 in conjunction with FIGS. 5 to 12 . In one embodiment, each of the detector sub-modules includes an array of scintillator pixels, each scintillator pixel of the array of scintillator pixels including a top surface receiving the X-rays, a bottom surface opposite the top surface, and a connection sides of the top and bottom surfaces. In one embodiment, the side surface is perpendicular to the XZ plane of the CT rotation system. The scintillator pixel array of the trapezoidal detector sub-module includes edge scintillator pixels along the Z direction and on both sides of the array, and the top surface of each edge scintillator pixel is trapezoidal. In one embodiment, the scintillator pixel array includes edge scintillator pixels 3111b along the Z-direction and on both sides of the array and intermediate scintillator pixels 3111a between the edge scintillator pixels. As shown in FIG. 13, the top surfaces of all scintillator pixels (edge scintillator pixel 3111b and middle scintillator pixel 3111a) are trapezoidal. For another example, as shown in FIG. 14, the shape of the top surface of the edge scintillator pixel 3111b is a trapezoid (the edge scintillator pixel is a right quadrangular prism whose top and bottom surfaces are trapezoids), and the top surface of the middle scintillator pixel 3111a is a trapezoid. The shape of is a rectangle (it can be understood that the middle scintillator pixel is a cuboid or a cube). In other embodiments, at least the width of the top surface of the edge scintillator pixel in the X direction gradually decreases along the Z direction. As shown in FIG. 13 , the top surface of all the edge scintillator pixels 3111b is a trapezoid, which is in X The width in the direction gradually decreases along the Z direction; in FIG. 14 , the top surface of the edge scintillator pixel 3111b is a trapezoid whose width in the X direction gradually decreases along the Z direction. Since the pixels are small, the relationship between D1 and D2 in FIG. 15 can be referred to for this reduction method. In the X direction, the width of D2 is reduced relative to the width of D1. In other embodiments, as shown in FIG. 13 , the widths of the top surfaces of the intermediate scintillator pixels in the X direction are equal. By designing the top surfaces of the edge scintillator pixels as trapezoids, or by designing the top surfaces of all scintillator pixels as trapezoids, or by designing the top surfaces of the middle scintillator pixels 3111a as rectangles and the edge scintillator pixels The top surface of 3111b is designed as a trapezoid, so that the receiving area of rays can be maximized.

Although in the embodiments shown in FIGS. 9 to 12 , the widths of the top surfaces of the detector submodules in the Z direction are equal, the skilled person can also understand that the widths of the top surfaces 311 of the detector submodules in the Z direction are not equal. In this case, the length of the receptive field formed by the top surface on one side of the focal reference plane L is greater than that on the other side by arranging the detector sub-modules in an arc in the Z direction. The length of the receptive field on the side is sufficient.

Please refer to FIG. 15 and FIG. 16 , the above-mentioned solution in which the receptive field is asymmetric with respect to the focal reference plane of the X-ray source can also be applied to the following detector modules. In the detector module shown in the embodiment shown in FIG. 15 , the plurality of detector sub-modules include an intermediate detector sub-module located within a preset distance range of the focus reference plane and an edge detector sub-module outside the range, the focus reference plane passing through the focal point of the X-ray source center and parallel to the XY plane of the CT rotation system; each detector submodule includes a top surface that receives the ray, and the top surface of the edge detector submodules is arranged in an arc along the Z direction of the CT rotation system, so The top surfaces of the intermediate detector sub-modules are aligned along the Z-direction. As shown in FIG. 15 , the receptive field 32 includes a left receptive field 321 and a right receptive field 322 , the left receptive field 321 and the right receptive field 322 are asymmetrical with respect to the focal reference plane L, and the left receptive field 321 and the right receptive field 322 respectively have a part The receptive fields are linear, and the two parts of the receptive fields form a linear receptive field 323. This part of the receptive fields 323 corresponds to the middle detector sub-module, and its top surface is arranged in a straight line, and the other parts of the receptive fields correspond to the edge detector sub-modules. Its top surface is arranged in an arc. As shown in FIG. 16 , in one embodiment, the top surfaces of the detector submodules have the same width in the Z direction, and there are two intermediate detector submodules (detector submodules 31a6 and 31a7 on the right side of the focus reference plane L). ) and an edge detector submodule 31a8, there are two intermediate detector submodules 31a4 and 31a5 and three edge detector submodules 31a1, 31a2 and 31a3 on the left side of the focal reference plane L.

The present application also discloses a detector, which includes a housing and a plurality of detector modules according to any one of the foregoing, and the plurality of detector modules are arranged side by side on the X-direction of the CT rotation system. on the casing.

The detector module is not only suitable for use in imaging equipment that converts X-rays into visible light particles, such as GOS, and then obtains images through photoelectric conversion, etc., but also applies to cadmium zinc telluride crystals (CdZnTe , CZT) and other materials, and then use the imaging equipment to obtain images through data processing. Based on this, the present application also discloses a CT apparatus, which includes a scanning gantry, an X-ray source and any one of the aforementioned detectors, wherein the scanning gantry includes an opening for receiving a scanned object. The X-ray source is used for emitting rays to the scanning object. The detector and the X-ray source are disposed on opposite sides of the opening, and are used for receiving attenuated rays passing through the scanning object and converting the rays into electrical signals.

The above is only the preferred embodiment of the application, and does not limit the application in any form. Although the application has been disclosed in the preferred embodiment as above, it is not intended to limit the application. Anyone familiar with this professional technology Personnel, without departing from the scope of the technical solution of the present application, can make some changes or modifications to equivalent embodiments of equivalent changes by using the technical content disclosed above, provided that any content that does not depart from the technical solution of the present application, according to this Any simple modifications, equivalent changes and modifications made to the above embodiments by the technical essence of the application still fall within the scope of the technical solutions of the present application.

Claims (15)

1. A detector module for detecting the attenuated rays of the scanned object sent by the X-ray source of the CT host, wherein the detector module comprises a support and a plurality of detector sub-modules installed on the support ,in, Each detector sub-module includes a top surface for receiving rays, and the top surfaces of the plurality of detector sub-modules are arranged in an arc or in a line along the Z-direction of the CT rotation system of the CT host; The top surfaces of the plurality of detector sub-modules form a receptive field corresponding to the irradiation field of the X-ray source on the YZ plane of the CT rotation system, and the receptive field is asymmetric with respect to the focal reference plane of the X-ray source, The focal reference plane passes through the focal center of the X-ray source and is parallel to the XY plane of the CT rotation system. 2. The detector module according to claim 1, wherein the top surfaces of all detector sub-modules are distributed on the arc of the same target circle centered on the focal center of the X-ray source, or , the top surfaces of the plurality of detector sub-modules are distributed on the arc of the target circle with unequal radii with the focal center of the X-ray source as the center. 3 . The detector module according to claim 2 , wherein the radius of the target circle tangent to the top surfaces of the detector sub-modules on both sides of the focal reference plane is Rc, which is far from the focal reference plane. 4 . The radius of the target circle tangent to the top surface of the detector sub-module of the face is Rf, Rc<Rf. 4 . The detector module according to claim 1 , wherein the sum of the widths of the top surfaces of the detector submodules on one side of the focal reference plane along the Z direction is greater than that on the other side of the focal reference plane. 5 . The sum of the widths of the top surfaces of the detector submodules along the Z direction is such that the receptive field is asymmetric with respect to the focal reference plane. 5. The detector module of claim 1 or 4, wherein the X-ray source comprises a target disk, and a receptive field close to the target disk is smaller than a receptive field farther from the target disk. 6 . The detector module according to claim 1 , wherein the widths of the top surfaces of the plurality of detector sub-modules in the Z direction are equal or unequal. 7 . 7 . The detector module according to claim 1 , wherein the width of the top surface of the detector sub-module close to the focal reference plane in the X direction is greater than the top surface of the detector sub-module far from the focal reference plane. 8 . The width of the surface in the X direction is such that the width of the top surface in the X direction exhibits a decreasing trend from the focal reference plane along the Z direction away from the focal reference plane. 8 . The detector module according to claim 7 , wherein the width of the top surface of the detector sub-module close to the focal reference plane in the X direction is greater than the top surface of the detector sub-module far from the focal reference plane. 9 . The width of the surface in the X direction also includes: the top surface of the detector sub-module with the same distance from the focal reference surface has the same width in the X direction, or, a plurality of multiples within a preset range outside the preset distance from the focal reference surface The widths of the top surfaces of the detector sub-modules in the X direction are equal; or, a plurality of detector sub-modules within a preset range beyond the preset distance from the focus reference surface are rectangular parallelepipeds, and within the preset range The top surface of each detector submodule is equal in width in the X direction, equal in width in the Z direction, and equal in height in the Y direction for each detector submodule. 9 . The detector module according to claim 7 , wherein among the plurality of detector sub-modules, the shape of the top surface of at least one detector sub-module is a trapezoid. 10 . 10. The detector module of claim 9, wherein the trapezoid is an isosceles trapezoid. 11. The detector module of claim 9, wherein each of the detector sub-modules comprises an array of scintillator pixels, each scintillator pixel of the array comprising a top surface that receives the radiation; The scintillator pixel array of the detector sub-module with a trapezoidal top surface includes edge scintillator pixels along the Z direction and on both sides of the array, and the top surface of each edge scintillator pixel is trapezoidal in shape. 12. The detector module of claim 11, wherein the top surfaces of all scintillator pixels of the scintillator pixel array are trapezoidal; Alternatively, the scintillator pixel array includes intermediate scintillator pixels located between edge scintillator pixels, the top surfaces of the edge scintillator pixels are trapezoidal, and the top surfaces of the intermediate scintillator pixels are rectangular. 13. The detector module of claim 1, wherein each of the detector sub-modules includes a bottom surface opposite the top surface and sides connected to the top and bottom surfaces, the The sides are perpendicular to the XZ plane of the CT rotation system. 14. A detector, comprising a housing and a plurality of detector modules according to any one of claims 1 to 13, wherein a plurality of the detector modules are arranged side by side along the X direction of the CT rotation system. on the housing. 15. A CT apparatus, comprising a gantry, an X-ray source and the detector of claim 14, wherein, the gantry includes an opening for receiving a scanned object; the X-ray source is used for emitting rays to the scanning object; The detector and the X-ray source are disposed on opposite sides of the opening, and are used for receiving attenuated rays passing through the scanning object and converting the rays into electrical signals.

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