CT Performance Detection Phantom, Performance Detection Method, Device and CT Equipment

Abstract

The present application provides a CT performance detection phantom, a performance detection method, a device and a CT device. The phantom includes: a housing which is a cylindrical hollow structure, and positioning lines are provided on the outer peripheral wall of the housing along a direction perpendicular to the axis of the housing; a performance test module disposed inside the housing, and the performance test module includes at least one of a first module layer, a second module layer and a third module layer. Among them, the first module layer is used to detect the spatial resolution index and the slice thickness index, the second module layer is used to detect the accuracy index of CT value and the spatial linearity index, and the third module layer is used to detect the low contrast resolution index and the uniformity index of CT value; a base body connected to the housing, and a connection hole is provided on the base body; an adjusting member passing through the connection hole, and the adjusting member is used to adjust the height of the base body. Thereby, the CT image quality can be objectively evaluated, the difficulty of operating the mold is reduced, and both the detection accuracy and efficiency are taken into account.

Description

Technical Field

[0001] The present application relates to the technical field of CT medical imaging, and particularly relates to a CT performance detection phantom, a performance detection method, a device, and a CT device. Background Art

[0002] Medical computed tomography (CT) systems are now conventional medical devices. CT systems include fan-beam CT, cone-beam CT (abbreviated as CBCT in English), etc. High-quality CT images can improve the accuracy of tumor radiotherapy, maximize the protection of surrounding normal tissues, and reduce the damage to critical organs and surrounding normal tissues when applied to elastic deformation registration or adaptive radiotherapy. Therefore, it becomes particularly important to comprehensively evaluate the image quality of CT.

[0003] In related technologies, when using conventional CT and CBCT performance evaluation phantoms for CT performance detection, it is necessary to subjectively detect by manually adjusting the window width and window level to evaluate indicators such as the spatial resolution and low-contrast resolution of images. It is greatly affected by human factors and conditional factors, making the detection results inaccurate. Moreover, due to the limitations of the structure of existing phantoms, the process of positioning and adjusting the phantom is relatively complex, which is not conducive to user operation and seriously affects the efficiency of detecting image indicators. Summary of the Invention

[0004] In view of this, the present application provides a CT performance detection phantom, a performance detection method, a device, and a CT device, which can objectively and comprehensively evaluate the CT image quality, while reducing the difficulty of operating the mold, thereby improving the detection accuracy and efficiency of CT performance and being beneficial to reducing the test cost.

[0005] According to one aspect of the present application, a CT performance detection phantom is provided, including:

[0006] A housing, the housing is a cylindrical hollow structure, and along the direction perpendicular to the axis of the housing, a positioning line is provided on the outer peripheral wall of the housing, and the positioning line is used to position the central tomogram of the phantom;

[0007] A performance test module, disposed inside the housing, the performance test module includes at least one of a first module layer, a second module layer, and a third module layer, wherein the first module layer is used to detect the spatial resolution index and the tomogram thickness index, the second module layer is used to detect the accuracy index of CT value and the spatial linearity index, and the third module layer is used to detect the low-contrast resolution index and the CT value uniformity index;

[0008] A base body, connected to the housing, and a connection hole is provided on the base body, and an adjusting member is used to adjust the height of the base body;

[0009] The adjusting member is inserted through the connecting hole, and the adjusting member is used to adjust the height of the seat body.

[0010] Optionally, the first module layer includes: a first base material configured as a cylinder; a metal point source embedded in the first base material and located at the central fault of the first base material; at least two pairs of metal wires embedded in the first base material, and at least two pairs of metal wires are inclined with respect to the axial direction of the first base material and / or the direction perpendicular to the axis of the first base material;

[0011] The second module layer includes: a second base material configured as a cylinder, and the second base material is provided with four through holes along the axial direction of the second base material. The distances between the central points of the four through holes and the axis of the second base material are the same, and the distances between the central points of adjacent two through holes are the same; a plurality of test parts with different densities, and the plurality of test parts with different densities are embedded in the second base material;

[0012] The third module layer includes: a third base material configured as a cylinder.

[0013] Optionally, identification lines are provided on the outer peripheral wall of the housing, and the identification lines are used to indicate the positions of the first module layer, the second module layer, and the third module layer.

[0014] Optionally, the metal point source is a sphere, and the diameter of the metal point source is less than or equal to the preset spatial resolution of CT imaging.

[0015] Optionally, the lengths of the plurality of test parts with different densities are less than or equal to the length of the second base material.

[0016] Optionally, the outer diameter of the housing is 140 mm to 180 mm, the inner diameter is 120 mm to 160 mm, and the length is 70 mm to 150 mm.

[0017] According to another aspect of the present application, there is provided a performance detection method for a CT performance detection phantom provided in the first aspect, including:

[0018] When the phantom is in a preset position, scan the performance test module according to preset scanning parameters to obtain a central tomographic image;

[0019] Measure the spatial resolution index and the tomographic thickness index through the central tomographic image of the first module layer; and / or

[0020] Measure the CT value accuracy index and the spatial linear index through the central tomographic image of the second module layer; and / or

[0021] Measure the low contrast resolution index and the CT value uniformity index through the central tomographic image of the third module layer;

[0022] Evaluate the CT performance according to at least one of the spatial resolution index, slice thickness index, CT value accuracy index, spatial linearity index, low contrast resolution index, and CT value uniformity index, and the corresponding preset standard values.

[0023] Optionally, the first module layer includes: a first substrate, a metal point source, and at least two pairs of metal wires. The metal point source is located at the central slice of the first substrate. At least two pairs of metal wires are inclined with respect to the axial direction of the first substrate and / or the direction perpendicular to the axis of the first substrate to measure the spatial resolution index and the slice thickness index. Specifically, it includes:

[0024] Determine the region center of the target pixel region through centroid operation. The target pixel region is the pixel region where the metal point source is located in the central slice image of the first module layer; perform Fourier transform on the pulse signal obtained based on the region center to generate a modulation transfer function curve to determine the spatial resolution index;

[0025] Determine the length of each metal wire in the central slice image of the first module layer; obtain the inclination angle of each pair of metal wires with respect to the cross-section of the first substrate; calculate the slice thickness according to the length and the inclination angle; determine the average value of the slice thicknesses corresponding to at least two pairs of metal wires as the slice thickness index.

[0026] Optionally, the second module layer includes: a second substrate and multiple test parts with different densities. The second substrate is provided with four through holes along the axial direction of the second substrate to measure the CT value accuracy index and the spatial linearity index. Specifically, it includes:

[0027] According to the central slice image of the second module layer, detect the CT values of the regions corresponding to each test part; determine the CT values of the regions corresponding to all test parts as the CT value accuracy index;

[0028] Determine the central coordinates of the four through holes in the central slice image of the second module layer; determine the detection distance between the center points of two adjacent through holes according to the central coordinates; determine the detection distance as the index of spatial linearity.

[0029] Optionally, the third module layer includes a third substrate to measure the low contrast resolution index and the CT value uniformity index. Specifically, it includes:

[0030] Through edge detection algorithm and circle detection algorithm, determine the center point of the third substrate in the central slice image of the third module layer, and the central region where the center point of the third substrate is located;

[0031] Divide the central region into multiple first sub-regions according to the first preset size; detect the CT values of the first sub-regions based on the central tomographic image of the third module layer; determine the low contrast resolution index according to the preset contrast and the standard deviation of the CT values of the multiple first sub-regions.

[0032] Select multiple second sub-regions in the central tomographic image of the third module layer according to the second preset size; detect the CT values of the multiple second sub-regions and the central region based on the central tomographic image of the third module layer; determine the maximum difference between the CT values of the multiple second sub-regions and the CT value of the central region as the uniformity index of the CT value.

[0033] According to another aspect of the present application, there is provided a performance detection device for a CT performance detection phantom provided in the first aspect, including:

[0034] A scanning module, configured to scan the performance test module according to preset scanning parameters to obtain a central tomographic image when the phantom is located at a preset position;

[0035] A detection module, configured to measure the spatial resolution index and the slice thickness index through the central tomographic image of the first module layer; and / or measure the CT value accuracy index and the spatial linearity index through the central tomographic image of the second module layer; and / or measure the low contrast resolution index and the CT value uniformity index through the central tomographic image of the third module layer;

[0036] An evaluation module, configured to evaluate the CT performance according to at least one of the spatial resolution index, the slice thickness index, the CT value accuracy index, the spatial linearity index, the low contrast resolution index, and the CT value uniformity index, and the corresponding preset standard value.

[0037] Optionally, the first module layer includes: a first substrate, a metal point source, and at least two pairs of metal wires. The metal point source is located at the central slice of the first substrate, and at least two pairs of metal wires are inclined with respect to the axis direction of the first substrate and / or the direction perpendicular to the axis of the first substrate. The detection module specifically includes:

[0038] A spatial resolution detection module, configured to determine the regional center of the target pixel region through centroid calculation, where the target pixel region is the pixel region where the metal point source is located in the central tomographic image of the first module layer; perform Fourier transform on the pulse signal obtained based on the regional center to generate a modulation transfer function curve to determine the spatial resolution index;

[0039] The fault thickness detection module is used to determine the length of each metal wire in the central fault image of the first module layer; obtain the inclination angle of each pair of metal wires relative to the cross-section of the first substrate; calculate the fault thickness according to the length and the inclination angle; and determine the average value of the fault thicknesses corresponding to at least two pairs of metal wires as the fault thickness index.

[0040] Optionally, the second module layer includes: a second substrate and a plurality of test parts with different densities. The second substrate is provided with four through holes along the axis direction of the second substrate. The detection module specifically includes:

[0041] The accuracy detection module is used to detect the CT value of the area corresponding to each test part according to the central fault image of the second module layer; and determine the CT value accuracy index of all the areas corresponding to the test parts.

[0042] The spatial linearity detection module is used to determine the central coordinates of the four through holes in the central fault image of the second module layer; determine the detection distance between the central points of two adjacent through holes according to the central coordinates; and determine the detection distance as the spatial linearity index.

[0043] Optionally, the third module layer includes a third substrate. The detection module specifically includes:

[0044] The center detection module is used to determine the center point of the third substrate in the central fault image of the third module layer and the central area where the center point of the third substrate is located through an edge detection algorithm and a circle detection algorithm.

[0045] The low contrast resolution detection module is used to divide the central area into a plurality of first sub-areas according to a first preset size; detect the CT value of the first sub-areas according to the central fault image of the third module layer; and determine the low contrast resolution index according to a preset contrast and the standard deviation of the CT values of the plurality of first sub-areas.

[0046] The uniformity detection module is used to select a plurality of second sub-areas in the central fault image of the third module layer according to a second preset size; detect the CT values of the plurality of second sub-areas and the central area according to the central fault image of the third module layer; and determine the maximum difference between the CT values of the plurality of second sub-areas and the CT value of the central area as the CT value uniformity index.

[0047] According to another aspect of the present application, there is provided a CT device, including a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor. When the processor executes the computer program, the above performance detection method is implemented.

[0048] According to another aspect of the present application, there is provided a storage medium, on which a computer program is stored. When the program is executed by a processor, the above performance detection method is implemented.

[0049] With the above technical solution, the CT performance detection phantom includes four structural parts: a housing, a performance test module, a base body, and an adjusting member. The performance test module of the phantom can include the following three types. The first module layer can evaluate the image spatial resolution and slice thickness indicators; the second module layer can evaluate the spatial linearity and CT value accuracy indicators; the third module layer can evaluate the CT value uniformity and low contrast resolution indicators. On the one hand, there is no need for manual comprehensive detection of CT performance, achieving the purpose of objective evaluation, especially for the spatial resolution indicator and the low contrast resolution indicator, avoiding the influence of factors such as human, environment, and conditions, and improving the accuracy and detection efficiency of image quality evaluation. At the same time, it is possible to use the first module layer to detect the image spatial resolution and tomographic thickness indicators simultaneously, and use the third module layer to detect the CT value uniformity and low contrast resolution indicators simultaneously, omitting the modules for subjective evaluation of the spatial resolution indicator and the low contrast resolution indicator, which is beneficial to reducing the cost of the phantom and miniaturizing the phantom. On the other hand, the positioning line can not only be used to determine the position of the central tomogram, but also calibrate the placement position of the phantom, and the adjusting member can be used to adjust the placement of the phantom in an easier operation manner, saving time and effort, facilitating accurate placement, and further improving the detection efficiency. On the further hand, the phantom proposed in this application has stronger versatility and can be used for detection and calibration of different models of CT devices, such as cone beam CT, fan beam CT, etc., avoiding the need to change conditions midway, thus ensuring the consistency of traceability.

[0050] The above description is only an overview of the technical solution of this application. In order to be able to more clearly understand the technical means of this application, it can be implemented in accordance with the content of the specification. And in order to make the above and other purposes, features, and advantages of this application more obvious and understandable, the following specifically gives the specific implementation manners of this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The drawings described herein are used to provide a further understanding of this application and constitute a part of this application. The schematic embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation to this application. In the drawings:

[0052] Figure 1 shows a schematic structural diagram of the CT performance detection phantom provided by an embodiment of this application;

[0053] Figure 2 shows a schematic structural diagram of the first module layer provided by an embodiment of this application;

[0054] Figure 3 shows a cross-sectional view of the first module layer provided by an embodiment of this application;

[0055] Figure 4 shows a schematic structural diagram of the second module layer provided by an embodiment of this application;

[0056] Figure 5 Shows a cross-sectional view of the second module layer provided by the embodiment of the present application;

[0057] Figure 6 Schematic structural diagram of the third module layer provided by the embodiment of the present application;

[0058] Figure 7 Shows a cross-sectional view of the third module layer provided by the embodiment of the present application;

[0059] Figure 8 Shows a schematic flow diagram of a performance detection method provided by the embodiment of the present application;

[0060] Figure 9 Shows a structural block diagram of a performance detection device provided by the embodiment of the present application.

[0061] Reference numerals:

[0062] 11 housing, 12 performance test module, 13 base body, 14 adjusting member, 111 positioning line, 112 identification line, 121 first module layer, 122 second module layer, 123 third module layer, 1211 first substrate, 1212 metal point source, 1213 metal wire, 1221 second substrate, 1222 through hole, 1223 test portion, 1231 third substrate. Detailed implementation manners

[0063] The present application will be described in detail below with reference to the drawings and in conjunction with the embodiments. It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other.

[0064] In this embodiment, a CT performance detection phantom is provided, as Figure 1 shown. The CT performance detection phantom includes: a housing 11, a performance test module 12, a base body 13, and an adjusting member 14.

[0065] Specifically, the housing 11 is a cylindrical hollow structure. In a direction perpendicular to the axis of the housing 11, a positioning line 111 is provided on the outer peripheral wall of the housing 11. The positioning line 111 is used to position the central section of the phantom. The positioning line 111 is made of a metal material so that the CT device can accurately sense it. If the positioning line 111 is not in the central section of the reconstructed image, it means that the axis of this layer is not aligned with the center of the device after the phantom is positioned, and thus the central section image cannot be obtained; otherwise, the central section image of the phantom can be determined. Among them, the number of positioning lines is at least one.

[0066] Among them, the central section image is the cross-sectional (transverse section) image of the housing 11 and the performance test module 12 in the vertical axis direction indicated by the positioning line after the axis of the phantom is aligned with the scanning center of the CT device.

[0067] It can be understood that the number of positioning lines 111 can be set as required. For example, as Figure 2 and Figure 3 shown, four metal positioning lines (positioning lines 111) extending from the surface of the housing 11 towards the axis of the housing are respectively embedded in the 3 o'clock, 6 o'clock, 9 o'clock, and 12 o'clock directions of the housing 11. Since the metal positioning lines are embedded in the housing 11, they are represented by dashed lines in the figure. If the upper and lower positioning metal lines are not in the same tomogram of the reconstructed image, it indicates that there is a pitch angle in the up and down tilt after the phantom is positioned. If the left and right positioning metal lines are not in the same tomogram of the reconstructed image, it indicates that there is a left and right tilt after the phantom is positioned. If the positioning metal line is not in the central tomogram of the reconstructed image, it indicates that the center of this layer is not aligned with the isocenter of the device after the phantom is positioned. It can be seen that the four positioning metal lines can not only determine the position of the central tomogram, but also be used to judge the positioning accuracy of the phantom in three dimensions. As Figure 5 and Figure 7 shown, since the three module layers are closely arranged in the housing 11, only one positioning metal line is embedded in the 12 o'clock direction of the second module layer 122 and the third module layer 123 for calibration with the first module layer 121.

[0068] Furthermore, the performance test module 12 is disposed in the hollow space of the housing 11, such as the dashed part in Figure 1 . The performance test module 12 includes at least one of the first module layer 121, the second module layer 122, and the third module layer 123. Among them, the first module layer 121 is used to detect the spatial resolution index and the tomographic thickness index, the second module layer 122 is used to detect the accuracy index of CT value and the spatial linearity index, and the third module layer 123 is used to detect the low contrast resolution index and the uniformity index of CT value.

[0069] It should be noted that the number of the first module layer 121, the second module layer 122, and the third module layer 123, their positions within the housing 11, and the distance between adjacent ones of the first module layer 121, the second module layer 122, and the third module layer 123 can be set as required, and the embodiments of the present application do not make specific limitations. In addition, in order to ensure that the positioning line 111 can assist the user in positioning the central tomogram of each module layer, positioning lines 111 are provided on the housing at the position where each module layer is located, that is, the position of the positioning line 111 on the housing 11 corresponds to the first module layer 121, the second module layer 122, and the third module layer 123.

[0070] Further, the base 13 is connected to the housing 11. The base 13 is provided with connection holes (not shown in the figure). The base 13 is used to support the housing 11 that houses the performance test module 12. The adjusting member 14 is inserted through the connection hole. The adjusting member 14 is used to adjust the height of the base 13. Further, the mold body can be made horizontal by adjusting the height of the base 13.

[0071] In this embodiment, the CT performance detection mold body includes four structural parts: a housing 11, a performance test module 12, a base 13, and an adjusting member 14. Among them, the first module layer 121 in the performance detection module can evaluate the image spatial resolution and slice thickness indexes; the second module layer 122 can evaluate the spatial linearity and CT value accuracy indexes; the third module layer 123 can evaluate the CT value uniformity and low contrast resolution indexes. On the one hand, there is no need for manual comprehensive detection of CT performance, achieving the purpose of objective evaluation. Especially for the spatial resolution index and low contrast resolution index, it avoids the influence of factors such as human, environment, and conditions, and improves the accuracy and detection efficiency of image quality evaluation. At the same time, the first module layer 121 can be used to detect the image spatial resolution and tomographic thickness indexes simultaneously, or the third module layer 123 can be used to detect the CT value uniformity and low contrast resolution indexes simultaneously, omitting the modules for subjective evaluation of the spatial resolution index and low contrast resolution index, which is beneficial to reducing the cost of the mold body and miniaturizing the mold body. On the other hand, the positioning line 111 can not only be used to determine the position of the central tomogram, but also assist the marking line 112 on the housing 11 to calibrate the placement position of the mold body. And through the adjusting member 14, the placement position of the mold body can be adjusted in an easier operation manner, saving time and effort and facilitating accurate placement, further improving the detection efficiency. On the other hand, the mold body proposed in this application has stronger versatility and can be used for detection and calibration of different CT devices, such as cone beam CT, fan beam CT, etc., avoiding the need to change conditions midway, thus ensuring the consistency of traceability.

[0072] In actual application scenarios, such as Figure 1 shown, the adjusting member 14 is a threaded rod, and the connection hole is a threaded hole. The matching connection relationship between the threaded rod and the threaded hole can simplify the operation of adjusting the placement of the mold body.

[0073] In addition, the number of the adjusting member 14 and the connection hole is at least three, so as to adjust the horizontal position and height of the base 13 in multiple directions. Figure 1 Three adjusting members 14 are provided in. The base 13 is divided into left and right parts. The left and right sides of the base 13 suspend the housing 11. One threaded rod is provided on one side of the base 13, and two threaded rods are provided on the other side. When placing the mold body, if the mold body is not placed horizontally, by adjusting these three threaded rods and referring to the corresponding relationship between the marking line 112 on the housing 11 and the laser line in the CT device, it can be quickly adjusted to be horizontal, facilitating the accurate placement of the mold body.

[0074] As Figure 2 and Figure 3 shown, in the embodiment of the present application, further, the first module layer 121 includes: a first substrate 1211, a metal point source 1212, and at least two pairs of metal wires 1213.

[0075] Specifically, the first substrate 1211 is configured as a cylinder. The center of the first substrate 1211 is located on the axis of the housing, that is, the first substrate 1211 is coaxial with the housing 11.

[0076] The metal point source 1212 is embedded in the first substrate 1211 and is located at the central section of the first substrate 1211. Thus, in the central section image of the first module layer 121 obtained when the CT device scans the phantom, a pattern corresponding to the metal point source 1212 can appear, so as to evaluate the spatial resolution based on the data related to the pattern corresponding to the metal point source 1212 in the central section image.

[0077] Similarly, at least two pairs of metal wires 1213 are also embedded in the first substrate 1211. Each metal wire 1213 can be inclined relative to the axial direction of the first substrate 1211, can also be inclined relative to the direction perpendicular to the axis of the first substrate 1211, or can be inclined relative to both the axial direction and the direction perpendicular to the axis at the same time. In other words, each metal wire 1213 can be inclined along the X direction and / or the Y direction, so that there is a certain inclination angle α between the metal wire 1213 and the cross-section of the first substrate 1211, that is, the section perpendicular to the axial direction of the first substrate 1211.

[0078] In this embodiment, in the central section image of the first module layer 121 obtained when scanning the phantom, a pattern corresponding to the metal point source 1212 can appear. The pattern corresponding to the metal point source 1212 is used to determine the pixel region containing the metal point source 1212 in the central section image, and the spatial resolution is objectively evaluated by calculating the MTF curve using the point spread function based on this pixel region. On the one hand, it avoids the influence of human factors and environmental factors during the detection of spatial resolution and improves the accuracy of performance detection. On the other hand, the method of embedding point sources has a lower processing difficulty compared to line pairs, reducing the processing difficulty of the phantom. Moreover, the accuracy of calculating the MTF is basically not affected when the position of the embedded metal point source 1212 structure in the phantom is slightly misaligned, improving the fault tolerance rate. On the other hand, there is no need for a module structure for subjectively evaluating the spatial resolution index, which is beneficial to reducing the cost of the phantom and miniaturizing the phantom.

[0079] Further, since at least two pairs of metal wires 1213 are embedded in the first substrate 1211, multiple imaging patterns corresponding to the metal wires 1213 will also be included in the central tomographic image. It can be understood that the metal wires 1213 are imaged in the form of line segments in the central tomographic image, and the length of the line segment is related to the inclination angle of the metal wire 1213. After obtaining the central tomographic image by scanning, determine the length L of the line segment corresponding to the metal wire 1213 in the central tomographic image. The tomographic thickness ST can be calculated using the length L and the inclination angle α, where ST = L × tan(α). Finally, take the average of the tomographic thickness measurement results of all the metal wires 1213 as the index of the tomographic thickness. Thus, by embedding metal wires 1213 with a certain inclination angle in the first substrate 1211, the tomographic thickness is evaluated, achieving the effect of objectively evaluating the tomographic thickness.

[0080] It is worth mentioning that the metal point source 1212 is a sphere, and the diameter of the metal point source 1212 needs to be significantly smaller than the system preset limit spatial resolution required by the user, that is, the required pixel size. In this way, the response of the metal point source 1212 can accurately serve as a model of the point spread function. Thus, as much as possible, the measurement error is reduced, so that the detected spatial resolution index can be more accurate, which is beneficial to improving the accuracy of spatial resolution evaluation.

[0081] In the actual application scenario, the projections of the extension lines of each pair of metal wires 1213 in at least two pairs of metal wires 1213 in the axial direction of the first substrate 1211 and / or the direction perpendicular to the axis are in an intersecting state, that is, the inclination directions of the two metal wires 1213 that appear in pairs are opposite. Thus, the thickness index can be calculated from multiple directions to ensure the accuracy of thickness calculation. Moreover, the inclination angles of all the metal wires 1213 embedded in the first substrate 1211 can be the same, which is beneficial to simplifying the subsequent thickness calculation process.

[0082] Exemplarily, the material of the first substrate 1211 can be selected according to the CT value. For example, polymethyl methacrylate (PMMA).

[0083] As Figure 3 shown, two pairs of metal wires 1213 are embedded in the first substrate 1211, and the two pairs of metal wires 1213 appear as two parallel line segments on the central section, which can be approximately regarded as a square.

[0084] As Figure 4 and Figure 5 shown, in the embodiment of the present application, further, the second module layer 122 includes: a second substrate 1221 and multiple test parts 1223 with different densities.

[0085] Specifically, the second substrate 1221 is configured as a cylinder to facilitate loading into the housing 11. The center of the second substrate 1221 is located on the axis of the housing, that is, the second substrate 1221 is coaxial with the housing 11. The second substrate 1221 is provided with four through holes 1222 along the axis direction of the second substrate 1221. The distances between the central points of the four through holes 1222 and the axis of the second substrate 1221 are the same, and the distances between the central points of two adjacent through holes 1222 are the same. That is, the projections of the four through holes 1222 in the axis direction of the second substrate 1221 form a square. Preferably, the center of the square is located on the axis of the second substrate 1221. It can be understood that the material filled in the four through holes 1222 is air.

[0086] A plurality of test parts 1223 with different densities are embedded in the second substrate 1221. The test parts 1223 are used to measure the CT values of different materials. Among them, in order to test the CT values of different materials, the materials of the plurality of test parts 1223 with different densities include equivalent tissue ray attenuation materials simulating human fat, soft tissue, bone tissue, high-density bone, human organs, and muscle, water (solid water), air, or other polymer materials. The polymer materials can be selected from polyoxymethylene, acrylic acid, low-density polyethylene, polystyrene, or polymethylpentene (PMP), etc. The number and density of the test parts 1223 can be reasonably set according to the actual CT value test requirements, and the present application does not make specific limitations.

[0087] In actual application scenarios, the lengths of the plurality of test parts 1223 with different densities can be less than or equal to the length of the second substrate 1221, and at least part of the test parts 1223 is located in the central section of the second substrate 1221.

[0088] Specifically, for example, as Figure 4 and Figure 5 shown, 6 cylinders (test parts 1223) with different densities and four cylindrical holes (through holes 1222) are provided. The cylinders are air, the equivalent material of water (solid water), and the equivalent materials of human fat, soft tissue, bone tissue, and high-density bone respectively. The circular centers of the cylinders are on the same diameter circle with the axis of the second substrate 1221 as the center of the circle, and the angles formed by the centers of every two adjacent materials and the axis of the second substrate 1221 are the same. The projections of the four middle cylindrical holes on the central section are axisymmetric and form a square, and the side lengths of the square are the same, that is, the distances between the centers of the four cylindrical holes are equal.

[0089] In this embodiment, in the central tomographic image of the second module layer 122, the physical distances between the center points of the four through holes 1222 forming a square are measured respectively, and used as an index of spatial linearity, so as to evaluate the spatial linearity performance of the reconstructed image and determine whether geometric distortion occurs. At the same time, in this central tomographic image, the CT values of the regions corresponding to the test parts 1223 with multiple different densities are measured respectively, that is, the average CT values of different equivalent materials, and used as an index of the accuracy of the CT value, so as to accurately reflect the accuracy of the image of the CT device in actual use. After detecting the accuracy of the objective CT value and the spatial linearity index by using the second module layer 122, the automatic analysis of the CT performance can be realized through the corresponding standard values, which can not only improve the accuracy of the image quality analysis, but also improve the efficiency of the image quality analysis.

[0090] Exemplarily, the material of the second substrate 1221 can be selected according to the CT value as required. For example, polymethyl methacrylate (PMMA).

[0091] Such as Figure 6 and Figure 7 As shown in the embodiment of the present application, further, the third module layer 123 includes: a third substrate 1231, the third substrate 1231 is configured as a cylinder so as to be loaded into the housing 11, and the center of the third substrate 1231 is located on the axis of the housing, that is, the third substrate 1231 is coaxial with the housing 11.

[0092] In this embodiment, the material of the third substrate 1231 is an equivalent material of "solid water", for example, a methylstyrene compound, so that the third module layer 123 is formed into a uniform solid water layer. The uniformity of the CT value and the low contrast resolution can be evaluated by using the uniform solid water layer.

[0093] Among them, first, through the edge detection algorithm and the circle detection algorithm, the center point of the third substrate 1231 in the central tomographic image of the third module layer 123 and the central region where the center point of the third substrate 1231 is located are determined. Considering that when measuring the low contrast resolution, it is necessary to determine the size of the region that can be resolved when the mean difference between the low contrast object and the background distribution is the preset contrast C. Based on this, according to the first preset size, the central region is divided into multiple first sub-regions. Then, according to the preset contrast and the standard deviation of the CT values of the multiple first sub-regions, the low contrast resolution index is calculated. Thus, the low contrast resolution is objectively evaluated by using statistical methods. Compared with the subjective evaluation using slices with different densities and different diameters, the influence of human subjective factors and environmental factors is avoided, so that the evaluated low contrast resolution is more objective and the detection result is more accurate. At the same time, removing the structure of the subjective evaluation of the low contrast resolution index is beneficial to reducing the cost of the phantom.

[0094] Further, for the uniformity of CT values, multiple second sub-regions of the same size at different positions are selected in the central tomographic image according to the second preset size, the differences between the CT values detected at different positions are calculated respectively, and the maximum value among them is selected. The smaller the maximum difference is, the more uniform the CT value detection based on the same substrate is. Therefore, the maximum difference can be determined as the uniformity index of the CT value, and based on this, it can be analyzed whether the CT imaging is uniform.

[0095] As Figure 1 , Figure 2 , Figure 4 and Figure 6 shown, in the embodiment of the present application, further, a marking line 112 is provided on the outer peripheral wall of the housing 11, and the marking line 112 is used to indicate the positions of the first module layer 121, the second module layer 122, and the third module layer 123.

[0096] In this embodiment, since the performance test module 12 is placed in the housing 11, when scanning the phantom, it is impossible to accurately and intuitively determine the positions of the first module layer 121, the second module layer 122, and the third module layer 123. Therefore, the marking line 112 is provided at the required positions for scanning the first module layer 121, the second module layer 122, and the third module layer 123. Thus, the marking line 112 is used to locate the positions of the first module layer 121, the second module layer 122, and the third module layer 123 respectively, so that the scanning operator can quickly locate the required test module, improving the detection efficiency. Moreover, the placement position of the phantom is calibrated by the marking line 112 and the laser lamp of the CT device, and combined with the positioning line 111, it is further judged whether the phantom placement is accurate, facilitating the acquisition of a precise CT central tomographic image, and further improving the detection accuracy.

[0097] It should be noted that the marking line 112 can be located at the center position of each module layer on the housing 11 to assist in positioning the central tomography and calibrating the phantom placement, or can be located at other positions. The marking line 112 can be arranged along the circumferential direction of the housing 11 or along the axial direction of the housing 11, and the number of the marking lines 112 can be set as required, and the embodiments of the present application do not make specific limitations.

[0098] In the embodiment of the present application, further, the outer diameter of the housing is 140 mm to 180 mm, the inner diameter is 120 mm to 160 mm, and the length is 70 mm to 150 mm.

[0099] In this embodiment, since the phantom does not include a test module specifically for subjectively evaluating the spatial resolution index and the low contrast resolution index, the length of the housing is greatly reduced, making the phantom smaller in volume, realizing the miniaturization of the phantom, and being beneficial to reducing the cost of the phantom.

[0100] In addition, the thicknesses (heights of the cylinders) of the first module layer 121, the second module layer 122, and the third module layer 123 can be set as required, and the thicknesses of different module layers can be the same or different. For example, the outer diameter of the housing is 160 mm, the inner diameter is 140 mm, and the length is 100 mm. The diameters of the first module layer 121, the second module layer 122, and the third module layer 123 are the same, all being 140 mm. Among them, the thicknesses of the first module layer 121 and the second module layer 122 are the same, both being 20 mm, and the thickness of the third module layer 123 is 60 mm. At this time, the three module layers are in a closely fitting state within the housing 11, and the three module layers can abut against each other for positioning. This not only facilitates the miniaturization of the phantom and reduces the cost of the phantom, but also enhances the fixing strength of the module layers, preventing each module layer from tilting within the housing, so as to facilitate the acquisition of central tomographic images.

[0101] It can be understood that in order to prevent the reduction of the service life of the phantom caused by the mutual friction between two adjacent module layers within the housing 11, when designing the phantom, there is a gap between two adjacent module layers within the housing 11, that is, the distance between two adjacent module layers is greater than 0. At this time, a limiting member is provided on the inner peripheral wall of the housing 11 to fix the positions of the first module layer 121, the second module layer 122, and the third module layer 123, so as to prevent each module layer from tilting or shifting in position within the housing, which helps to reduce the performance detection error.

[0102] As Figure 8 shown, according to an embodiment of another aspect of the present application, a performance detection method for a CT performance detection phantom provided in the first aspect is provided. The method includes:

[0103] Step 201, when the phantom is located at a preset position, scan the performance test module according to preset scanning parameters to obtain a central tomographic image;

[0104] Among them, the central tomographic image is the cross-sectional image of the housing and the performance test module found according to the positioning line embedded on the housing after the axis of the phantom is aligned with the scanning center of the CT device. Specifically, if the positioning line is not in the central tomogram of the reconstructed image, it means that the axis of this layer after the phantom is positioned is not aligned with the scanning center of the device.

[0105] Step 202, measure the spatial resolution index and the tomographic thickness index through the central tomographic image of the first module layer; and / or measure the CT value accuracy index and the spatial linearity index through the central tomographic image of the second module layer; and / or measure the low contrast resolution index and the CT value uniformity index through the central tomographic image of the third module layer;

[0106] Among them, the above indicators are the test data calculated after the CT device scans the phantom. By comparing the above indicators with the corresponding preset standard values, it can be determined whether the detected indicators meet the user's requirements.

[0107] Step 203, evaluate the CT performance according to at least one of the spatial resolution index, slice thickness index, CT value accuracy index, spatial linearity index, low contrast resolution index, and CT value uniformity index, and the corresponding preset standard values.

[0108] It can be understood that for the detection items of CT performance detection (spatial resolution, slice thickness, CT value accuracy, spatial linearity, low contrast resolution, and CT value uniformity), they can be selected as needed. When performing performance evaluation, only need to compare the indicators of the detection items required by the user with their corresponding preset standard values.

[0109] In this embodiment, on the one hand, there is no need for manual comprehensive detection of CT performance, achieving the purpose of objective evaluation. Especially for the spatial resolution index and low contrast resolution index, it avoids the influence of factors such as human, environment, and conditions, and improves the accuracy and detection efficiency of image quality evaluation. On the other hand, this method has stronger versatility and can be used for the detection and calibration of different models of CT devices, such as cone beam CT, fan beam CT, etc., avoiding the need to change conditions midway, thus ensuring the consistency of traceability.

[0110] In the embodiment of the present application, further, the first module layer includes: a first substrate, a metal point source, and at least two pairs of metal wires. The metal point source is located in the central slice of the first substrate, and at least two pairs of metal wires are inclined with respect to the axial direction of the first substrate and / or the direction perpendicular to the axis of the first substrate. Measuring the spatial resolution index specifically includes:

[0111] Determine the regional center of the target pixel region through centroid operation. The target pixel region is the pixel region where the metal point source is located in the central slice image of the first module layer; perform Fourier transform on the pulse signal obtained based on the regional center to generate a modulation transfer function curve to determine the spatial resolution index.

[0112] In this embodiment, in the central tomographic image of the first module layer obtained when scanning the phantom, a pattern corresponding to the metal point source can appear. Based on the pattern corresponding to the metal point source, the Modulation Transfer Function (MTF) curve is calculated in the form of a point spread function. Specifically, the pixel region containing the metal point source in the central tomographic image is determined through the pattern corresponding to the metal point source, and the centroid calculation method is used to locate the center of the sub-pixel level pixel region of the metal point source. A pulse signal is generated according to the center of the pixel region, and then the Fourier transform is performed on the pulse signal to obtain the MTF curve. Using the MTF curve as an index of spatial resolution to evaluate the spatial resolution of the CT device can avoid the influence of human factors and environmental factors and improve the accuracy of the evaluation. Moreover, since the pixel region is determined by the embedded metal point source structure, even when there is a slight error in the phantom positioning, it will not affect the accuracy of calculating the MTF, and the error tolerance is higher.

[0113] In the embodiment of the present application, further, the first module layer includes: a first substrate, a metal point source, and at least two pairs of metal wires. The metal point source is located in the central tomography of the first substrate, and at least two pairs of metal wires are inclined with respect to the axis direction of the first substrate and / or the direction perpendicular to the axis of the first substrate. Measuring the tomographic thickness index specifically includes:

[0114] Determine the length of each metal wire in the central tomographic image of the first module layer; obtain the inclination angle of each pair of metal wires with respect to the cross-section of the first substrate; calculate the tomographic thickness according to the length and the inclination angle; and determine the average value of the tomographic thicknesses corresponding to at least two pairs of metal wires as the tomographic thickness index.

[0115] In this embodiment, since at least two pairs of metal wires are embedded in the first substrate, then, the central tomographic image will also include imaging patterns corresponding to multiple metal wires. It can be understood that the metal wires are imaged in the form of line segments in the central tomographic image, and the length of the line segment is related to the inclination angle of the metal wire. After obtaining the central tomographic image by scanning, determine the physical length L of the line segment corresponding to the metal wire in the central tomographic image. The tomographic thickness ST can be calculated using the length L and the inclination angle α, where ST = L×tan(α). Finally, take the average of the tomographic thickness measurement results of all metal wires as the index of the tomographic thickness. Thus, the effect of objectively evaluating the tomographic thickness is achieved.

[0116] In the embodiment of the present application, further, the second module layer includes: a second substrate and multiple test parts with different densities. The second substrate is provided with four through holes along the axis direction of the second substrate. Measuring the accuracy index of the CT value specifically includes:

[0117] According to the central tomographic image of the second module layer, detect the CT values of the corresponding regions of each test part; determine the CT values of the corresponding regions of all test parts as the accuracy index of the CT values.

[0118] In this embodiment, in the central tomographic image of the second module layer, measure the CT values of the corresponding regions of multiple test parts with different densities, that is, the average CT values of different equivalent materials, and use them as the accuracy index of the CT values, so as to accurately reflect the accuracy of the images of the CT device in actual use. After detecting the objective accuracy and spatial linearity indexes of the CT values by using the second module layer, the automatic analysis of the CT performance can be realized through the corresponding standard values. This can not only improve the accuracy of image quality analysis, but also improve the efficiency of image quality analysis.

[0119] In the embodiment of the present application, further, the second module layer includes: a second base material and multiple test parts with different densities, and the second base material is provided with four through holes along the axis direction of the second base material. Measuring the spatial linearity index specifically includes:

[0120] Determine the central coordinates of the four through holes in the central tomographic image of the second module layer; according to the central coordinates, determine the detection distance between the center points of two adjacent through holes; determine the detection distance as the index of spatial linearity.

[0121] In this embodiment, in the central tomographic image of the second module layer, sequentially connect the center points of the four through holes, and use the central coordinates to calculate the physical distances between the center points of two adjacent through holes respectively, and use them as the index of spatial linearity, so as to evaluate the spatial linearity performance of the reconstructed image and judge whether geometric distortion occurs.

[0122] Specifically, for example, as Figure 3 shown, find the central tomographic image according to the positioning lines embedded on the shell in multiple tomographic images reconstructed by the second layer module, and then in this tomographic image, measure the physical distances of each pair of parallel lines of the center points of the four through holes forming a square respectively, and use them as the index of spatial linearity. Since the distances between the center points of two adjacent through holes in the phantom are the same, if there are differences between the detection distances obtained through the central tomographic image, it indicates that there are quality problems with the spatial linearity of the CT device imaging.

[0123] In the embodiment of the present application, further, the third module layer includes a third base material, and measuring the low contrast resolution index specifically includes:

[0124] Through the edge detection algorithm and the circle detection algorithm, determine the center point of the third base material in the central tomographic image of the third module layer, and the central region where the center point of the third base material is located;

[0125] Divide the central region into multiple first sub-regions according to a first preset size; detect the CT values of the first sub-regions based on the central tomographic image of the third module layer; determine the low-contrast resolution index according to a preset contrast ratio and the standard deviation of the CT values of the multiple first sub-regions.

[0126] In this embodiment, first, the center point of the third base material in the central tomographic image of the third module layer and the central region where the center point of the third base material is located are determined through an edge detection algorithm and a circle detection algorithm. Considering that when measuring the low-contrast resolution, it is necessary to determine the area size that can be resolved when the mean difference between the low-contrast object and the background distribution is the preset contrast ratio. Based on this, the central region is divided into multiple first sub-regions according to the first preset size. Then, according to the standard deviation of the CT values of the multiple first sub-regions, the size of the object that can be resolved at the preset contrast ratio, that is, the low-contrast resolution index, is obtained. Thus, the statistical method is used to objectively evaluate the low-contrast resolution. Compared with the subjective evaluation using slices with different densities and different diameters, this avoids the influence of human subjective factors and environmental factors, makes the evaluated low-contrast resolution more objective, the detection result more accurate, and at the same time removes the structure for subjectively evaluating the low-contrast resolution index, which is beneficial to reducing the cost of the phantom.

[0127] Among them, the preset contrast ratio, that is, the low-contrast level required by the user, can be reasonably set as needed.

[0128] In actual application scenarios, in order to further improve the calculation accuracy of the low-contrast resolution index, multiple different first preset sizes can be set to divide the central region by different first preset sizes respectively, so as to obtain multiple groups of first sub-regions. Each group of first sub-regions includes multiple first sub-regions obtained by dividing the central region according to each first preset size. Calculate the standard deviation of the CT values of the first sub-regions corresponding to each first preset size respectively, and fit the standard deviations of the CT values corresponding to multiple first preset sizes. Use the fitted result and the preset contrast to calculate the low-contrast resolution index. For example, use the Canny edge detection and Hough circle detection methods to find the center and central region of the solid water layer. Then, for different size values (first preset sizes) M1, M2,..., Mn of different low-contrast levels, divide the central region respectively. Specifically, first divide this central region into several squares (first sub-regions) of size M1×M1 according to M1, and calculate the standard deviation σ1 of the average CT values of these squares. Then divide this central region into several squares of size M2×M2 according to M2, and calculate the standard deviation σ2 of the average CT values of these squares, and so on, until this central region is divided into several squares of size Mn×Mn according to Mn, and calculate the standard deviation σn of the average CT values of these squares. After the standard deviation calculation is completed, take σ1, σ2,..., σn as the independent variable sequence, and take M1, M2,..., Mn as the dependent variable sequence for fitting. Calculate the contrast resolution index according to the fitting result.

[0129] In an embodiment of the present application, further, the third module layer includes a third substrate, and measures the uniformity index of the CT value, specifically including:

[0130] Through the edge detection algorithm and the circle detection algorithm, determine the center point of the third substrate in the central tomographic image of the third module layer, and the central region where the center point of the third substrate is located;

[0131] According to the second preset size, select multiple second sub-regions in the central tomographic image of the third module layer; detect the CT values of the multiple second sub-regions and the central region according to the central tomographic image of the third module layer; determine the maximum difference between the CT values of the multiple second sub-regions and the CT values of the central region as the uniformity index of the CT value.

[0132] In this embodiment, multiple second sub-regions of the same size at different positions are selected in the central tomographic image according to the second preset size, and the differences between the CT values detected at different positions are calculated respectively, and the maximum value among them is selected. The smaller the maximum difference, the more uniform the CT value detection based on the same substrate. Therefore, the maximum difference can be determined as the uniformity index of the CT value, and based on this, it can be analyzed whether the CT imaging is uniform.

[0133] It is understandable that the CT value of a region is the average of the CT values of each pixel point within the region.

[0134] In an actual application scenario, when referring to the second sub-region, to ensure the accuracy of detection, it is necessary to make the second sub-regions as evenly distributed as possible. At this time, the center points of multiple second sub-regions are respectively located on the connection line between the positioning point and the center point of the third substrate in the central tomographic image, as well as the center point of the third substrate, and the positioning point corresponds to the identification line of the housing. For example, on this tomographic image, a second sub-region of the same size is selected at the center of the phantom region and in the directions of 3, 6, 9, and 12 o'clock. Then, the maximum difference between the average CT value of the second sub-regions in the directions of 3, 6, 9, and 12 o'clock and the average CT value of the central region is calculated, and this maximum difference is used as the uniformity index of the CT value.

[0135] As Figure 9 shown, further, as a specific implementation of the above performance detection method, an embodiment of the present application provides a performance detection device, including: a scanning module, a detection module, and an evaluation module.

[0136] The scanning module is used to scan the performance test module according to preset scanning parameters to obtain a central tomographic image when the phantom is in a preset position; the detection module is used to measure the spatial resolution index and the tomographic thickness index through the central tomographic image of the first module layer; and / or measure the CT value accuracy index and the spatial linearity index through the central tomographic image of the second module layer; and / or measure the low contrast resolution index and the CT value uniformity index through the central tomographic image of the third module layer; the evaluation module is used to evaluate the CT performance according to at least one of the spatial resolution index, the tomographic thickness index, the CT value accuracy index, the spatial linearity index, the low contrast resolution index, and the CT value uniformity index, and the corresponding preset standard value.

[0137] In this embodiment, on the one hand, there is no need for manual comprehensive detection of CT performance, achieving the purpose of objective evaluation, especially for the spatial resolution index and the low contrast resolution index, avoiding the influence of factors such as human, environment, and conditions, and improving the accuracy and detection efficiency of image quality evaluation. On the other hand, this method has stronger versatility and can be used for the detection and calibration of different CT devices, such as cone beam CT, fan beam CT, etc., avoiding the need to change conditions midway, thus ensuring the consistency of traceability.

[0138] Further, the first module layer includes: a first substrate, a metal point source, and at least two pairs of metal wires. The metal point source is located at the central tomography of the first substrate, and at least two pairs of metal wires are inclined with respect to the axial direction of the first substrate and / or the direction perpendicular to the axis of the first substrate. The detection module specifically includes:

[0139] A spatial resolution detection module (not shown in the figure) is used to determine the regional center of the target pixel region through centroid operation. The target pixel region is the pixel region where the metal point source is located in the central tomographic image of the first module layer; perform Fourier transform on the pulse signal obtained based on the regional center to generate a modulation transfer function curve, so as to determine the spatial resolution index;

[0140] A tomographic thickness detection module (not shown in the figure) is used to determine the length of each metal line in the central tomographic image of the first module layer; obtain the inclination angle of each pair of metal lines relative to the cross-section of the first substrate; calculate the tomographic thickness according to the length and the inclination angle; determine the average value of the tomographic thicknesses corresponding to at least two pairs of metal lines as the tomographic thickness index.

[0141] Optionally, the second module layer includes: a second substrate and multiple test parts with different densities. The second substrate is provided with four through holes along the axis direction of the second substrate. The detection module specifically includes:

[0142] An accuracy detection module (not shown in the figure) is used to detect the CT value of the corresponding region of each test part according to the central tomographic image of the second module layer; determine the CT value of all the corresponding regions of the test parts as the accuracy index of the CT value;

[0143] A spatial linearity detection module (not shown in the figure) is used to determine the central coordinates of the four through holes in the central tomographic image of the second module layer; determine the detection distance between the central points of two adjacent through holes according to the central coordinates; determine the detection distance as the spatial linearity index.

[0144] Optionally, the third module layer includes a third substrate. The detection module specifically includes:

[0145] A center detection module (not shown in the figure) is used to determine the center point of the third substrate in the central tomographic image of the third module layer and the central region where the center point of the third substrate is located through an edge detection algorithm and a circle detection algorithm;

[0146] A low contrast resolution detection module (not shown in the figure) is used to divide the central region into multiple first sub-regions according to the first preset size; detect the CT value of the first sub-region according to the central tomographic image of the third module layer; determine the low contrast resolution index according to the preset contrast and the standard deviation of the CT values of the multiple first sub-regions;

[0147] A uniformity detection module (not shown in the figure) is used to select multiple second sub-regions in the central tomographic image of the third module layer according to the second preset size; detect the CT values of the multiple second sub-regions and the central region according to the central tomographic image of the third module layer; determine the maximum difference between the CT values of the multiple second sub-regions and the CT value of the central region as the uniformity index of the CT value.

[0148] It should be noted that for other corresponding descriptions of each functional module involved in the performance detection device provided in the embodiments of the present application, reference can be made to Figure 8 the corresponding description, which will not be elaborated here.

[0149] Based on the above-mentioned Figure 8 performance detection method as shown, correspondingly, the embodiments of the present application also provide a storage medium on which a computer program is stored, and when the program is executed by a processor, it implements the above-mentioned Figure 8 performance detection method as shown.

[0150] Based on such an understanding, the technical solution of the present application can be embodied in the form of a software product, a hardware product, or a combination of software and hardware. The software product can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.), and includes several instructions for causing a CT device (which can be a personal computer, a server, or a network device, etc.) to execute the methods in various implementation scenarios of the present application.

[0151] Based on the above-mentioned Figure 8 method as shown, and Figure 9 the performance detection device embodiments as shown, in order to achieve the above purpose, the embodiments of the present application also provide a CT device, which includes a storage medium and a processor; the storage medium is used to store a computer program; the processor is used to execute the computer program to implement the above-mentioned Figure 8 performance detection method as shown.

[0152] Those skilled in the art can understand that the structure of a CT device provided in this embodiment does not constitute a limitation on the CT device, and it may include more or fewer components, or combine certain components, or have different component arrangements.

[0153] The storage medium may also include an operating system and a network communication module. The operating system is a program for managing and storing the hardware and software resources of the CT device, and supports the operation of information processing programs and other software and / or programs. The network communication module is used to implement the communication between each control in the storage medium, as well as the communication between the storage medium and other hardware and software in the entity device.

[0154] Through the description of the above embodiments, those skilled in the art can clearly understand that the present application can be implemented by means of software plus a necessary general hardware platform, or can also be implemented by hardware.

[0155] Those skilled in the art can understand that the attached drawings are only schematic diagrams of a preferred implementation scenario, and the units or processes in the attached drawings are not necessarily essential for implementing the present application. Those skilled in the art can understand that the units in the devices in the implementation scenario can be distributed in the devices in the implementation scenario according to the description of the implementation scenario, or can be correspondingly changed and located in one or more devices different from the present implementation scenario. The units in the above implementation scenario can be combined into one unit, or can be further split into multiple sub-units.

[0156] The above serial numbers of the present application are only for description and do not represent the advantages or disadvantages of the implementation scenario. The above-disclosed are only several specific implementation scenarios of the present application. However, the present application is not limited thereto, and any changes that can be thought of by those skilled in the art should fall within the protection scope of the present application.

Claims

1. A CT performance detection phantom, characterized in that, it includes: A housing, the housing is a cylindrical hollow structure. Along the direction perpendicular to the axis of the housing, positioning lines are provided on the outer peripheral wall of the housing, and the positioning lines are used to position the central tomogram of the phantom; A performance test module, which is arranged inside the housing. The performance test module includes: a first module layer, a second module layer, and a third module layer. Among them, the first module layer is used to detect the spatial resolution index and the tomogram thickness index, the second module layer is used to detect the CT value accuracy index and the spatial linearity index, and the third module layer is used to detect the low contrast resolution index and the CT value uniformity index; The first module layer includes: A first base material, the first base material is configured as a cylinder; A metal point source, the metal point source is embedded in the first base material and is located at the central tomogram of the first base material. The metal point source is a sphere, and the diameter of the metal point source is smaller than the pixel size corresponding to the preset spatial resolution of the required CT imaging system; At least two pairs of metal wires for detecting the tomogram thickness index, the at least two pairs of metal wires are embedded in the first base material, and the at least two pairs of metal wires are inclined with respect to the axis direction of the first base material; A seat body, which is connected to the housing, and a connection hole is provided on the seat body; An adjusting member, which is inserted through the connection hole, and the adjusting member is used to adjust the height of the seat body.

2. The CT performance detection phantom according to claim 1, characterized in that, The second module layer includes: A second base material, the second base material is configured as a cylinder, and the second base material is provided with four through holes along the axis direction of the second base material. The distances between the center points of the four through holes and the axis of the second base material are the same, and the distances between the center points of adjacent two through holes are the same; A plurality of test parts with different densities, the plurality of test parts with different densities are embedded in the second base material; The third module layer includes: A third base material, the third base material is configured as a cylinder.

3. The CT performance detection phantom according to claim 2, characterized in that, Marking lines are provided on the outer peripheral wall of the housing, and the marking lines are used to indicate the positions of the first module layer, the second module layer, and the third module layer; and / or The lengths of the plurality of test parts with different densities are less than or equal to the length of the second base material.

4. The CT performance detection phantom according to any one of claims 1 to 3, characterized in that, The outer diameter of the housing is 140mm - 180mm, the inner diameter is 120mm - 160mm, and the length is 70mm - 150mm.

5. A performance detection method for a CT performance detection phantom according to any one of claims 1 to 4, characterized in that, it includes: When the phantom is in a preset position, scanning the performance test module according to preset scanning parameters to obtain a central tomogram; Measuring the spatial resolution index and the tomogram thickness index through the central tomogram of the first module layer; and / or Measure the accuracy index of CT value and the spatial linearity index through the central tomographic image of the second module layer; and / or Measure the low-contrast resolution index and the uniformity index of CT value through the central tomographic image of the third module layer; Evaluate the CT performance according to at least one of the spatial resolution index, the tomographic thickness index, the accuracy index of CT value, the spatial linearity index, the low-contrast resolution index, and the uniformity index of CT value, and the corresponding preset standard value; The measurement of the spatial resolution index specifically includes: Determine the regional center of the target pixel region through centroid operation, where the target pixel region is the pixel region where the metal point source is located in the central tomographic image of the first module layer; Perform Fourier transform on the pulse signal obtained based on the regional center to generate a modulation transfer function curve to determine the spatial resolution index.

6. According to the performance detection method described in claim 5, characterized in that, The measurement of the tomographic thickness index specifically includes: Determine the length of each metal wire in the central tomographic image of the first module layer; Obtain the inclination angle of each pair of metal wires relative to the cross-section of the first substrate; Calculate the tomographic thickness according to the length and the inclination angle; Determine the average value of the tomographic thicknesses corresponding to the at least two pairs of metal wires as the tomographic thickness index.

7. According to the performance detection method described in claim 5, characterized in that, The second module layer includes a second substrate and multiple test parts with different densities. The second substrate is provided with four through holes along the axis direction of the second substrate. The measurement of the accuracy index of CT value and the spatial linearity index specifically includes: Detect the CT value of the corresponding region of each test part according to the central tomographic image of the second module layer; Determine the CT values of the corresponding regions of all test parts as the accuracy index of CT value; Determine the central coordinates of the four through holes in the central tomographic image of the second module layer; Determine the detection distance between the central points of adjacent two through holes according to the central coordinates; Determine the detection distance as the index of spatial linearity.

8. According to the performance detection method described in claim 5, characterized in that, The third module layer includes a third substrate. The measurement of the low-contrast resolution index and the uniformity index of CT value specifically includes: Determine the center point of the third substrate and the central region where the center point of the third substrate is located in the central tomographic image of the third module layer through an edge detection algorithm and a circle detection algorithm; Divide the central region into multiple first sub-regions according to a first preset size; Detect the CT values of the first sub-regions according to the central tomographic image of the third module layer; Determine the low-contrast resolution index according to a preset contrast and the standard deviation of the CT values of the multiple first sub-regions; Select multiple second sub-regions in the central tomographic image of the third module layer according to a second preset size; Detect the CT values of the multiple second sub-regions and the central region according to the central tomographic image of the third module layer; Determine the maximum difference between the CT values of the multiple second sub-regions and the CT value of the central region as the uniformity index of the CT value.

9. A performance detection device for a CT performance detection phantom according to any one of claims 1 to 4, characterized in that, the device includes: a scanning module, configured to scan the performance test module according to preset scanning parameters to obtain a central tomographic image when the phantom is located at a preset position; a detection module, configured to measure the spatial resolution index and the slice thickness index through the central tomographic image of the first module layer; and / or measure the CT value accuracy index and the spatial linearity index through the central tomographic image of the second module layer; and / or measure the low contrast resolution index and the CT value uniformity index through the central tomographic image of the third module layer; an evaluation module, configured to evaluate the CT performance according to at least one of the spatial resolution index, the slice thickness index, the CT value accuracy index, the spatial linearity index, the low contrast resolution index, and the CT value uniformity index, and a corresponding preset standard value, wherein the measurement of the spatial resolution index specifically includes: Determine the regional center of the target pixel region through centroid operation, where the target pixel region is the pixel region where the metal point source is located in the central tomographic image of the first module layer; Perform Fourier transform on the pulse signal obtained based on the regional center to generate a modulation transfer function curve to determine the spatial resolution index.

10. A CT device, including a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor, characterized in that, when the processor executes the computer program, the performance detection method according to any one of claims 5 to 8 is implemented.

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