X-ray CT imaging apparatus and method for controlling x-ray CT imaging apparatus

Abstract

To shorten the time required for observing one object while accurately extracting a collision area in an X-ray CT imaging apparatus.SOLUTION: An X-ray CT scanner 100 includes a stage 22, an X-ray source 12, an X-ray detector 14, a 1CT imaging for reconstructing a plurality of X-ray images input from the X-ray detector and generating CT images of an object W, and a control device 30 for performing the 2CT imaging. The X-ray source irradiates an object with X-rays. The X-ray detector outputs a plurality of X-ray images of the object. The stage moves and rotates. The control device performs 1CT imaging and 2CT imaging on the object, extracts a collision region A indicating a range where the X-ray source and the object may collide with each other from the 1CT imaging, and determines an imaging position of the stage with respect to the X-ray source when the 2CT imaging is performed based on the collision region and a region of interest ROI indicating an observation range in the object.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an X-ray CT imaging apparatus and a control method for an X-ray CT imaging apparatus, and more particularly to a technique for preventing a collision between an X-ray source and an object in an X-ray CT imaging apparatus. [Background technology]

[0002] In an X-ray CT imaging device, the closer the object is to the X-ray source, the higher the magnification can be for CT imaging of the object. When the shape of the object is complex, the distance that the X-ray source can approach the object, i.e., the magnification that can be obtained, varies depending on the location of the object being imaged.

[0003] During CT imaging, the user manually tested whether the X-ray source would collide with the object and set the distance the X-ray source could approach the object each time they changed at least one of the magnification and imaging location. However, because this was done manually, there was a possibility that the user could misinterpret the test results or input an incorrect setting for the distance. Furthermore, because the user had to manually start the CT imaging in addition to the test each time they changed at least one of the magnification and imaging location, the time required to observe one object could be relatively long.

[0004] As a measure to prevent collision between the X-ray source and the object during such CT imaging, for example, Patent Publication No. 2022-139381 (Patent Document 1) discloses a CT device that acquires three-dimensional data of the object to be inspected using a 3D camera installed above the object, and automatically sets an approachable area based on the three-dimensional data. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-139381 Summary of the Invention [Problem to be solved by the invention]

[0006] In JP 2022-139381 A (Patent Document 1), the approachable area was set based on data obtained by photographing an object from above and below using a 3D camera and a mirror. As a result, the approachable area for parts of the object that cannot be recognized from above and below was set larger than the actual approachable area, which could result in the object being photographed at a magnification lower than the actual magnification that can be achieved.

[0007] Therefore, when photographing a part of an object that cannot be recognized by a 3D camera, in order to increase the magnification as much as possible, it is necessary to manually test whether the X-ray source will collide with the object, as in the past, and to set the distance at which the X-ray source can approach the object, which can result in a relatively long time being required to observe one object.

[0008] The present disclosure has been made to solve the above-mentioned problems, and its purpose is to shorten the time required to observe one object in an X-ray CT imaging device while appropriately extracting a collision area that matches the overall shape of the object. [Means for solving the problem]

[0009] An X-ray CT imaging apparatus according to one aspect of the present disclosure includes a stage on which an object is placed, an X-ray source, an X-ray detector, and a control device that performs first and second CT imaging, which reconstruct multiple X-ray images input from the X-ray detector and generate a CT image of the object. The X-ray source irradiates the object with X-rays. The X-ray detector is disposed opposite the X-ray source across the object and outputs multiple X-ray images of the object. The stage moves in a direction connecting the X-ray source and the X-ray detector and rotates around a rotation axis perpendicular to the stage. The control device performs the first and second CT imaging of the object, extracts a collision region indicating a range where the X-ray source and the object may collide from the data of the first CT imaging, and determines the imaging position of the stage relative to the X-ray source when performing the second CT imaging based on the collision region and a region of interest indicating an observation range of the object.

[0010] A control method according to another aspect of the present disclosure relates to a control method for an X-ray CT imaging apparatus. The X-ray CT imaging apparatus includes a stage on which an object is placed, an X-ray source, and an X-ray detector. The X-ray source irradiates the object with X-rays. The X-ray detector is disposed opposite the X-ray source across the object and outputs multiple X-ray images of the object. CT imaging involves reconstructing the multiple X-ray images input from the X-ray detector to generate a CT image of the object. The stage is movable in the X-axis direction connecting the X-ray source and the X-ray detector and rotatable around a rotation axis perpendicular to the stage. The control method includes the steps of performing a first CT scan on the object, extracting a collision area from data obtained in the first CT scan, which indicates the area where the X-ray source and the object may collide, determining the scanning position of the stage relative to the X-ray source when performing a second CT scan based on the collision area and a region of interest indicating the observation area in the object, moving the stage to the scanning position, performing the second CT scan on the object, and reconstructing and outputting the X-ray image obtained in the second CT scan. [Effects of the Invention]

[0011] The X-ray CT imaging device disclosed herein uses three-dimensional data from CT imaging to extract a collision area that matches the overall shape of the object, making it possible to perform CT imaging at an appropriate magnification while avoiding collisions between the X-ray source and the object, even for areas that cannot be recognized by a 3D camera. This allows the appropriate position of the stage during imaging to be automatically set for any part of the object, eliminating the need to manually determine the stage position during imaging even when imaging multiple locations, thereby reducing the time required to observe one object. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram showing an example of the overall configuration of an X-ray CT imaging apparatus according to an embodiment. [Figure 2] FIG. 2 is a functional block diagram of a control device in the X-ray CT imaging apparatus. [Figure 3] FIG. 10 is a diagram showing a method for extracting a collision region based on high-speed CT imaging by a control device. [Figure 4] FIG. 10 is a diagram showing changes in the impact area depending on the height. [Figure 5] 10 is a diagram showing a method for setting a region of interest at height Z1 and a method for determining an imaging position by a control device. FIG. [Figure 6] 10 is a diagram showing a method for setting a region of interest at height Z2 and a method for determining an imaging position by the control device. FIG. [Figure 7] 10 is a diagram showing a method for setting a region of interest at height Z3 and a method for determining an imaging position by the control device. FIG. [Figure 8] 3 is a flowchart showing a processing procedure of the X-ray CT imaging apparatus according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated.

[0014] 1 is a diagram showing an example of the overall configuration of an X-ray CT imaging apparatus 100 according to an embodiment. The X-ray CT imaging apparatus 100 performs CT (Computed Tomography) imaging using X-rays. As shown in FIG. 1, the X-ray CT imaging apparatus 100 includes a casing 10, a control device 30, an input device 40, and an output device 50.

[0015] The casing 10 houses an X-ray source 12, an X-ray detector 14, a base 20, rails 21, and a stage 22. The X-ray source 12 irradiates an object with an X-ray beam. The X-ray beam is a bundle of X-rays that expands in a cone shape from a focal point at its apex. The X-ray source 12 is, for example, an X-ray tube.

[0016] In the following description, the direction connecting the X-ray source 12 and the X-ray detector 14 will be referred to as the X-axis direction. The direction perpendicular to the X-axis direction and parallel to the surface of the stage 22 will be referred to as the Y-axis direction. The direction perpendicular to the X-axis and Y-axis directions, i.e., the normal direction to the stage 22, will be referred to as the Z-axis direction.

[0017] The X-ray detector 14 is provided opposite the X-ray source 12 across the stage 22. The X-ray detector 14 detects a two-dimensional distribution of X-ray intensity attenuated according to the transmission path of the X-ray. The X-ray detector 14 is configured, for example, by a flat panel detector (FPD). The X-ray detector 14 may be configured to be movable.

[0018] Rails 21 are fixed to the surface plate 20 so as to extend in the X-axis direction. A stage 22 is movably installed on the rails 21. The stage 22 further includes a base plate 24, a table 26, and a rotation stage .

[0019] The base plate 24 is configured to be movable in the X-axis direction on the rails 21. The base plate 24 is moved in the X-axis direction by, for example, a ball screw (not shown) arranged on the surface plate 20.

[0020] The table 26 is movably installed on the base plate 24. The table 26 moves in the Y-axis direction and the Z-axis direction. The table 26 moves in the Y-axis direction and the Z-axis direction, for example, by two ball screws (not shown) arranged on the base plate 24.

[0021] The rotating stage 28 is rotatably installed on the table 26. The rotating stage 28 rotates around a rotation axis extending in the Z-axis direction with an object placed on it. By rotating the rotating stage 28, the X-ray CT imaging apparatus 100 can capture images of the object from a horizontal direction to obtain X-ray images, and reconstruct a CT image from the obtained multiple X-ray images. The rotating stage 28 rotates around the rotation axis, for example, by a motor (not shown) arranged on the table 26.

[0022] Furthermore, the stage 22 can be moved in the X-, Y-, and Z-axis directions relative to the X-ray source 12, the X-ray detector 14, the base plate 20, and the rails 21 by the base plate 24 and the table 26. By moving the rotation stage 28 in the X-, Y-, and Z-axis directions and then rotating, the X-ray CT imaging device 100 can perform CT imaging by changing the magnification centered on a part of the object.

[0023] The controller 30 further comprises a communication interface 32 , a memory 34 and a processor 36 .

[0024] The communication interface 32 receives an operation to start CT imaging, etc. The communication interface 32 also transmits control signals to the X-ray source 12, the base plate 24, the table 26, and the rotation stage 28.

[0025] The memory 34 stores X-ray images, CT images, an operating system, and application programs, and is configured to include, for example, a read-only memory (ROM), a random access memory (RAM), and a flash memory.

[0026] The processor 36 controls each device of the X-ray CT imaging apparatus 100 based on the data acquired from the communication interface 32 and the data stored in the memory 34. The processor 36 is, for example, an arithmetic processing device such as a CPU (Central Processing Unit) and an MPU (Micro Processing Unit).

[0027] The input device 40 receives operation input from a user and transmits it to the control device 30. The input device 40 is, for example, a keyboard, a touch panel, or a mouse. The input device 40 may be located outside the X-ray CT imaging apparatus 100.

[0028] The output device 50 receives and outputs the results of CT imaging and the like from the control device 30. The output device 50 is, for example, a display or a printer. The output device 50 may be located outside the X-ray CT imaging apparatus 100.

[0029] Previously, the approachable area was set based on data obtained by photographing the object from above and below using a 3D camera and mirror. As a result, the approachable area for parts of the object that could not be recognized from above or below was set larger than the actual approachable area, which could result in images being captured at a lower magnification than was actually possible.

[0030] Furthermore, when photographing an unrecognizable part of an object, in order to increase the magnification as much as possible, it is necessary to manually test whether the X-ray source will collide with the object and set the distance at which the X-ray source can approach the object, which can result in a relatively long time required to observe one object.

[0031] Therefore, in the X-ray CT imaging device 100 of the embodiment, three-dimensional data from CT imaging is used to extract a collision area that matches the overall shape of the object, thereby performing CT imaging at an appropriate magnification while avoiding collision between the X-ray source and the object, even for areas that cannot be recognized by the 3D camera. This allows the appropriate position of the stage during imaging to be automatically set for any part of the object, eliminating the need to manually determine the position of the stage during imaging even when imaging multiple areas, thereby reducing the time required to observe one object.

[0032] 2 is a functional block diagram of the control device 30 in the X-ray CT imaging device 100. As shown in FIG. 2, the control device 30 includes a first CT imaging unit 62, a collision region extraction unit 63, a region of interest setting unit 64, an imaging position determination unit 65, a stage driving unit 66, and a second CT imaging unit 67.

[0033] The first CT imaging unit 62 controls the X-ray source 12 and the rotating stage 28 in response to receiving a start operation from the user via the input device 40 to perform CT imaging (first CT imaging). The first CT imaging is a CT imaging performed to detect a collision region, and is performed prior to CT imaging (second CT imaging) performed for actual observation. The first CT imaging is performed faster than the second CT imaging because its purpose is to recognize the external shape of the object rather than for observation.

[0034] Hereinafter, the first CT imaging performed at this high speed will be referred to as “high-speed CT imaging.” Specifically, the first CT imaging unit 62 emits an X-ray beam from the X-ray source 12 toward the X-ray detector 14, rotates the rotation stage 28 at a speed faster than that during the second CT imaging, and obtains an X-ray image of the object from the X-ray detector 14.

[0035] In addition, the high-speed CT scan uses a smaller total amount of X-rays than the second CT scan, resulting in a lower resolution image. During high-speed CT scans, the various parameters for the CT scan are set to values ​​that result in a faster scan speed at the expense of lower resolution.

[0036] For example, the second CT scan may take 30 to 35 seconds, while the high-speed CT scan may take 4 to 5 seconds. Alternatively, the imaging area of ​​the object may be limited in the high-speed CT scan. For example, the object may be rotated halfway (180 degrees) around the axis of rotation, rather than being imaged once (360 degrees) around the axis of rotation.

[0037] The first CT imaging unit 62 reconstructs multiple X-ray images obtained from the X-ray detector 14 during high-speed CT imaging to generate a maximum intensity projection (MIP) image of the object. An MIP image is an image in which volume data is projected in any direction and the maximum CT value among multiple voxels existing on the ray path of each slice is projected.

[0038] The collision region extraction unit 63 extracts a collision region based on the MIP image generated by the first CT imaging unit 62. The collision region indicates the range in which the X-ray source 12 and the object may collide. For example, when performing CT imaging of the object at the highest possible magnification, it is necessary to perform the CT imaging by positioning the X-ray source 12 as close as possible to the object.

[0039] In this case, even if the X-ray source 12 does not collide with the object before the start of CT imaging, the rotation of the rotating stage 28 after the start of CT imaging may cause the object to collide with the X-ray source 12. Therefore, the collision area is the area through which the object may pass when it rotates 360 degrees.

[0040] Specifically, from the MIP image of the XY plane perpendicular to the Z axis and the MIP image of the Z plane perpendicular to the X or Y axis, the collision area extraction unit 63 extracts a circle whose radius is the distance from the rotation axis to the point in the object that is farthest from the rotation axis on a plane parallel to the XY plane at each height from the surface of the rotation stage 28. The collision area extraction unit 63 then stacks the extracted circular areas by height to extract a three-dimensional collision area that corresponds to the overall shape of the object.

[0041] The region of interest setting unit 64 receives user input from the input device 40 and sets a region of interest in the object that the user wishes to observe in more detail. The region of interest indicates the observation range of the object. In the X-ray CT imaging device 100 of the present application, the object is enlarged and a second CT scan is performed on the region of interest set by the user, thereby obtaining an X-ray image with higher resolution for the region of interest. The user may set multiple regions of interest at the same time for one object.

[0042] The user may set the region of interest by specifying at least one of the regions on the ZX plane, the XY plane, and the YZ plane of the object displayed on a display device such as a display, and the magnification.

[0043] Note that the user may be prevented from setting a region of interest that would cause the X-ray source 12 to enter the collision region in advance. Furthermore, if the user sets a region of interest that would cause the X-ray source 12 to enter the collision region, the region of interest setting unit 64 may display a message on the output device 50 indicating that measurement is not possible.

[0044] The imaging position determination unit 65 determines an imaging position, which is the position of the stage 22 relative to the X-ray source 12, when performing the second CT imaging. To this end, first, in response to a start operation from the user via the input device 40, the imaging position determination unit 65 determines the range and magnification of CT imaging that can be achieved within a range where the object and the X-ray source 12 do not collide, taking into consideration the collision region and the region of interest.

[0045] From the region of interest set by the range, the imaging position determination unit 65 sets the maximum magnification that allows the entire range specified by the user to fit within the angle of view. Furthermore, from the region of interest set by the magnification, the imaging position determination unit 65 sets a range in which CT imaging of the object can be performed at the magnification specified by the user, centered on the rotation axis. In this way, the imaging position determination unit 65 determines the range and magnification of CT imaging that can be achieved within a range in which the object and the X-ray source 12 do not collide, taking into account the region and / or magnification set by the user and the collision region extracted by the collision region extraction unit 63.

[0046] The imaging position determination unit 65 determines the position of the stage 22 where CT imaging can be performed with the determined range and magnification as the imaging position. The imaging position is expressed by coordinates using the X-axis, Y-axis, and Z-axis, for example.

[0047] The stage driving unit 66 controls the base plate 24 and the table 26 to move the stage 22 to the imaging position.

[0048] The second CT imaging unit 67 performs second CT imaging on the object. Specifically, the second CT imaging unit 67 emits an X-ray beam from the X-ray source 12 toward the X-ray detector 14, rotates the rotating stage 28, and acquires an X-ray image of the object covering 180 degrees or 360 degrees around the rotation axis from the X-ray detector 14.

[0049] The second CT imaging is performed by rotating the object 180 degrees or 360 degrees using the rotating stage 28. The second CT imaging is performed, for example, in approximately 33 seconds. The second CT imaging unit 67 then reconstructs the obtained X-ray image to generate a CT image. The second CT imaging unit 67 then outputs the generated CT image to the output device 50.

[0050] Here, if the region of interest setting unit 64 has set multiple regions of interest, based on a single start operation by the user, the shooting position determination unit 65, the stage driving unit 66, and the second CT shooting unit 67 repeatedly and continuously perform the above processing for the multiple regions of interest.

[0051] In this way, the X-ray CT imaging apparatus 100 of the embodiment uses three-dimensional data obtained by CT imaging to extract a collision area that matches the overall shape of the object, thereby making it possible to perform CT imaging at an appropriate magnification even for areas that cannot be recognized by a 3D camera while avoiding collision between the X-ray source 12 and the object. This makes it possible to automatically set an appropriate position for the stage 22 during imaging for any part of the object, eliminating the need to manually determine the position of the stage 22 during imaging even when imaging multiple areas, thereby reducing the time required to observe one object.

[0052] 3 is a diagram for explaining in more detail the method for extracting a collision region based on high-speed CT imaging by the control device 30. Specifically, FIG. 3 shows the X-ray CT imaging device 100 on the XY plane as viewed from above. When the control device 30 performs high-speed CT imaging, an X-ray beam 16 is emitted from the X-ray source 12. A portion of the emitted X-ray beam passes through the object W on the stage 22 and reaches the X-ray detector 14.

[0053] Hereinafter, the distance from the center of the X-ray source 12 to the rotation axis RO will be referred to as the source to rotation center distance (SRD), and the distance from the center of the X-ray source 12 to the X-ray detector 14 will be referred to as the source to detector distance (SDD).

[0054] When performing CT imaging, the distances SRD and SDD are changed to change the magnification of the object. In the X-ray CT imaging apparatus 100 of the embodiment, the distance SDD is fixed, and the distance SRD is variable. As the distance SRD is shortened, the magnification of the object W increases.

[0055] The X-ray detector 14 generates an X-ray image in which the amount of detected X-rays is represented by shades of color. The control device 30 rotates the stage 22 while continuously detecting X-rays emitted from the X-ray source 12 and passing through the object W with the X-ray detector 14, thereby generating multiple X-ray images when X-rays are irradiated from multiple directions.

[0056] The control device 30 reconstructs the generated X-ray image to generate an MIP image of the XY plane perpendicular to the Z axis and an MIP image of a plane parallel to the Z axis. Based on the generated MIP images, the control device 30 extracts a circle of the collision area A at each height.

[0057] Specifically, when the size of the object W at a certain height is as shown in Fig. 3, the control device 30 determines the distance from the rotation axis RO to the farthest end P of the object W as the radius Ar of the circle of the collision area at the certain height. The three-dimensional collision area A is extracted by stacking the circles of radius Ar calculated at each height in the height direction (Z-axis direction).

[0058] In this way, in the X-ray CT imaging device 100 of the embodiment, by using three-dimensional data obtained by CT imaging to extract a collision area A that matches the overall shape of the object W, it is possible to perform CT imaging at an appropriate magnification even for areas that cannot be recognized by a 3D camera while avoiding collision between the X-ray source 12 and the object W. This makes it possible to automatically set an appropriate position for the stage 22 during imaging for any part of the object W, eliminating the need to manually determine the position of the stage 22 during imaging even when imaging multiple areas, thereby reducing the time required to observe one object W.

[0059] Figure 4 is a diagram showing an example of the change in the collision area A depending on the height. If the object W has a shape similar to three cylinders of different radii stacked on top of each other, when the object W is viewed on the ZX plane from the negative direction of the Y axis, it will appear as shown in the left diagram of Figure 4. The rotation axis RO of the stage 22 passes through the three cylinders.

[0060] The XY plane at height Z1 of the object W is as shown in Figure 4(a). The center of the circle W1 of the object at height Z1 is offset from the rotation axis RO of the stage 22. In this case, the control device 30 extracts a circle A1 of the collision area at height Z1, with the distance from the rotation axis RO to the farthest end P1 of the object circle W1 as the radius Ar1.

[0061] The XY plane at height Z2 of the object W is as shown in Figure 4(b). The center of the circle W2 of the object at height Z2 overlaps with the rotation axis RO of the stage 22. At this time, the control device 30 extracts a circle A2 of the collision area at height Z2, with the distance from the rotation axis RO to the farthest end of the object circle W2 as the radius Ar2.

[0062] The XY plane at height Z3 of the object W is as shown in Figure 4(c). The center of the circle W3 of the object at height Z3 is offset from the rotation axis RO of the stage 22. In this case, the control device 30 extracts a circle A3 of the collision area at height Z3, with the distance from the rotation axis RO to the farthest end P3 of the object circle W3 as the radius Ar3.

[0063] Finally, the collision area A of the entire object is extracted by combining the circles A1, A2, and A3 of the collision areas at each height and referring to the diagram on the ZX plane.

[0064] Fig. 5 is a diagram showing a method for setting a region of interest at height Z1 and a method for determining a photographing position by control device 30. As shown in the left diagram of Fig. 5, it is assumed that a user sets a region of interest ROI1 for an object W on the ZX plane. At this time, the XY plane at height Z1 of object W becomes as shown in the right diagram of Fig. 5. As described with reference to Fig. 4, control device 30 sets a collision region circle A1 for the object circle W1. Furthermore, the user sets a region of interest ROI1.

[0065] The control device 30 determines the imaging position at height Z1 so that the region of interest ROI1 is constantly exposed to the X-ray beam 16 emitted from the X-ray source 12 toward the X-ray detector 14 while the object W rotates 360 degrees, and so that the X-ray source 12 is not included in the collision area circle A1. The region of interest ROI1 includes the farthest end P1 of the object circle W1 from the rotation axis RO. Therefore, the distance SRD1 from the center of the X-ray source 12 to the rotation axis RO is as shown in the right diagram of Figure 5. The distance SDD is constant.

[0066] Fig. 6 is a diagram showing a method for setting a region of interest at height Z2 and a method for determining a photographing position by control device 30. As shown in the left diagram of Fig. 6, it is assumed that a user sets a region of interest ROI2 for an object W on the ZX plane. At this time, the XY plane at height Z2 of object W becomes as shown in the right diagram of Fig. 6. As described with reference to Fig. 4, control device 30 sets a collision region circle A2 for the object circle W2. Furthermore, the user sets a region of interest ROI2.

[0067] The control device 30 determines the imaging position at height Z2 so that the region of interest ROI2 is constantly exposed to the X-ray beam 16 emitted from the X-ray source 12 toward the X-ray detector 14 while the object W rotates 360 degrees, and so that the X-ray source 12 is not included in the collision region circle A2. The region of interest ROI2 includes the farthest end of the object circle W2 from the rotation axis RO. Therefore, the distance SRD2 from the center of the X-ray source 12 to the rotation axis RO is as shown in the right diagram of Figure 6. The distance SDD is constant.

[0068] At this time, when the XY plane is referenced, the X-ray source 12 is included in the circle A1 of the collision region at height Z1, but does not collide with the object W, as with the X-ray source 12 in the left diagram of Fig. 6. However, depending on the dimension of the X-ray source 12 in the height direction, there is a possibility that the X-ray source 12 may collide with the object W near height Z1. Therefore, when the X-ray source 12 enters the collision region A at any height when reference is made to the XY plane, the control device 30 also references the ZX plane to confirm that the X-ray source 12 is not entering the collision region A at any height.

[0069] Fig. 7 is a diagram showing a method for setting a region of interest at height Z3 and a method for determining a photographing position by the control device 30. As shown in the left diagram of Fig. 7, it is assumed that the user sets a region of interest ROI3 for an object W on the ZX plane. At this time, the XY plane at height Z3 of the object W becomes as shown in the right diagram of Fig. 7. As described with reference to Fig. 4, the control device 30 sets a collision region circle A3 for the object circle W3. Furthermore, the user sets the region of interest ROI3.

[0070] The control device 30 determines the imaging position at height Z3 so that the region of interest ROI3 is constantly exposed to the X-ray beam 16 emitted from the X-ray source 12 toward the X-ray detector 14 while the object W rotates 360 degrees, and so that the X-ray source 12 is not included in the collision region circle A3. The region of interest ROI3 does not include the farthest end P3 of the object circle W2 from the rotation axis RO. Therefore, the distance SRD3 from the center of the X-ray source 12 to the rotation axis RO is as shown in the right diagram of Figure 7. The distance SDD is constant.

[0071] As shown in FIGS. 5 to 7, the X-ray source can be brought as close as possible to the object while avoiding collision with the object, depending on the region of interest set by the user.

[0072] When the user sets regions of interest ROI1, ROI2, and ROI3 together for one object W, the control device 30 can automatically set the imaging position corresponding to each region of interest and move the stage with a single start operation by the user, thereby performing CT imaging continuously for the regions of interest ROI1, ROI2, and ROI3.

[0073] In this way, in the X-ray CT imaging device 100 of the embodiment, by using three-dimensional data obtained by CT imaging to extract a collision area A that matches the overall shape of the object W, it is possible to perform CT imaging at an appropriate magnification even for areas that cannot be recognized by a 3D camera while avoiding collision between the X-ray source 12 and the object W. This makes it possible to automatically set an appropriate position for the stage 22 during imaging for any part of the object W, eliminating the need to manually determine the position of the stage 22 during imaging even when imaging multiple areas, thereby reducing the time required to observe one object W.

[0074] 8 is a flowchart showing the processing procedure of the X-ray CT imaging apparatus 100 according to the embodiment. First, the user places the object W on the stage 22 (step S1). Next, in response to a start operation for starting high-speed CT imaging from the user via the input device 40, the X-ray CT imaging apparatus 100 performs high-speed CT imaging (step S2).

[0075] The control device 30 extracts a collision region A based on the data obtained by high-speed CT imaging using the method described with reference to Figures 4 to 7 (step S3). The user sets a region of interest ROI using the input device 40 (step S4). The user inputs a start operation to start CT imaging into the input device 40 (step S5).

[0076] Next, in response to the user's operation to start CT imaging, the control device 30 determines the imaging position so that the X-ray image includes the region of interest ROI and the X-ray source 12 is not included in the collision region A (step S6). Next, the control device 30 controls the base plate 24 and the table 26 to move the stage 22 to the imaging position (step S7).

[0077] Next, the X-ray CT imaging apparatus 100 performs CT imaging (step S8). Next, the control device 30 determines whether or not CT imaging has been performed on all regions of interest ROI designated by the user (step S9).

[0078] If CT imaging has been completed for all regions of interest ROI (YES in step S9), the output device 50 displays the CT images (step S10). If CT imaging has not been performed for all regions of interest ROI, in other words, if there are still regions of interest ROI to be subjected to CT imaging (NO in step S9), the control device 30 returns the process to step S6 and performs CT imaging for the remaining regions of interest ROI.

[0079] In this way, in the X-ray CT imaging device 100 of the embodiment, by using three-dimensional data obtained by CT imaging to extract a collision area A that matches the overall shape of the object W, it is possible to perform CT imaging at an appropriate magnification even for areas that cannot be recognized by a 3D camera while avoiding collision between the X-ray source 12 and the object W. This makes it possible to automatically set an appropriate position for the stage 22 during imaging for any part of the object W, eliminating the need to manually determine the position of the stage 22 during imaging even when imaging multiple areas, thereby reducing the time required to observe one object W. [Aspect] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0080] (Item 1) An X-ray CT imaging device according to one embodiment includes a stage on which an object is placed, an X-ray source, an X-ray detector, and a control device that performs first and second CT imaging, which reconstruct multiple X-ray images input from the X-ray detector and generate a CT image of the object. The X-ray source irradiates the object with X-rays. The X-ray detector is disposed opposite the X-ray source across the object and outputs multiple X-ray images of the object. The stage moves in a direction connecting the X-ray source and the X-ray detector and rotates around a rotation axis perpendicular to the stage. The control device may perform the first and second CT imaging of the object, extract a collision region from the data of the first CT imaging, which indicates the area where the X-ray source and the object may collide, and determine the imaging position of the stage relative to the X-ray source when performing the second CT imaging, based on the collision region and a region of interest, which indicates the observation area of ​​the object.

[0081] According to the X-ray CT imaging apparatus described in paragraph 1, a technique is provided that makes it possible to determine the imaging position of the stage based on the collision region and the region of interest.

[0082] (Item 2) In the X-ray CT imaging apparatus described in item 1, the collision region may include a region through which the object can pass when the object rotates once around the rotation axis on the stage.

[0083] According to the X-ray CT imaging apparatus described in the second aspect, a technique for extracting a collision region is provided.

[0084] (Item 3) In the X-ray CT imaging device described in item 1 or 2, the collision area may include an area in which circles perpendicular to the rotation axis, with the radius being the distance from the rotation axis to the farthest end of the object for each height from the stage, are stacked in the direction of the rotation axis for each height.

[0085] According to the X-ray CT imaging apparatus described in Section 3, a technique for extracting a collision region as small as possible is provided.

[0086] (4) In the X-ray CT imaging device described in any one of paragraphs 1 to 3, the control device may determine the imaging position so that the X-ray image includes the region of interest and the X-ray source is not included in the collision region.

[0087] According to the X-ray CT imaging apparatus described in item 4, a technique for determining the stage position is provided.

[0088] (Item 5) In the X-ray CT imaging device according to any one of Items 1 to 4, the first CT imaging may be performed on the entire object in order to extract the collision region.

[0089] According to the X-ray CT imaging device described in Section 5, a technique is provided that makes it possible to extract a collision region based on the first CT imaging.

[0090] (Item 6) In the X-ray CT imaging apparatus according to any one of Items 1 to 5, the second CT imaging may be performed on a region of interest of an object placed on a stage at the imaging position.

[0091] According to the X-ray CT imaging apparatus described in paragraph 6, a technique for performing a second CT imaging on a region of interest of an object is provided.

[0092] (Item 7) In the X-ray CT imaging apparatus according to any one of Items 1 to 6, the first CT imaging may be performed at a higher speed than the second CT imaging.

[0093] According to the X-ray CT imaging device described in Section 7, a technique for appropriately extracting a collision region that matches the overall shape of an object is provided.

[0094] (Item 8) In the X-ray CT imaging apparatus according to any one of Items 1 to 7, the control device may determine the region of interest based on an operation input entered by a user.

[0095] The X-ray CT imaging apparatus described in paragraph 8 provides a technique that allows a user to determine a region of interest.

[0096] (Item 9) In the X-ray CT imaging apparatus described in Item 8, the operation input may include at least one of the imaging range and the magnification.

[0097] The X-ray CT imaging apparatus described in paragraph 9 provides a technique that allows a user to determine a region of interest based on the range or magnification to be imaged.

[0098] (Item 10) In the X-ray CT imaging device described in any one of Items 1 to 9, the control device may perform the first CT imaging or the second CT imaging based on a start operation from the user.

[0099] According to the X-ray CT imaging device described in paragraph 10, a technique is provided that allows a user to instruct the start of the first CT imaging and the second CT imaging.

[0100] (Item 11) In the X-ray CT imaging device described in any one of items 8 to 10, the control device may determine a first area and a second area as the area of ​​interest for each imaging range or magnification, and may perform a second CT imaging targeting the first area and a second CT imaging targeting the second area consecutively based on a single start operation from the user.

[0101] According to the X-ray CT imaging apparatus described in paragraph 11, a technique is provided that makes it possible to perform second CT imaging consecutively on a plurality of regions of interest.

[0102] (Item 12) A control method according to one aspect relates to a control method for an X-ray CT imaging apparatus. The X-ray CT imaging apparatus includes a stage on which an object is placed, an X-ray source, and an X-ray detector. The X-ray source irradiates the object with X-rays. The X-ray detector is disposed opposite the X-ray source across the object and outputs multiple X-ray images of the object. CT imaging involves reconstructing the multiple X-ray images input from the X-ray detector to generate a CT image of the object. The stage is movable in the X-axis direction connecting the X-ray source and the X-ray detector, and is rotatable around a rotation axis perpendicular to the stage. The control method may include the steps of performing a first CT scan on the object, extracting a collision area from data obtained in the first CT scan, the collision area indicating the area where the X-ray source and the object may collide, determining the scanning position of the stage relative to the X-ray source when performing a second CT scan based on the collision area and a region of interest indicating the observation area of ​​the object, moving the stage to the scanning position, performing the second CT scan on the object, and reconstructing and outputting the X-ray image obtained in the second CT scan.

[0103] According to the control method for an X-ray CT imaging apparatus described in paragraph 12, a technique is provided that makes it possible to determine the imaging position of the stage based on the collision region and the region of interest.

[0104] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0105] 10 casing, 12 X-ray source, 14 X-ray detector, 16 X-ray beam, 20 surface plate, 21 rail, 22 stage, 24 base plate, 26 table, 28 rotation stage, 30 control device, 32 communication interface, 34 memory, 36 processor, 40 input device, 50 output device, 100 X-ray CT imaging device.

Claims

1. a stage on which an object is placed; an X-ray source for irradiating the object with X-rays; an X-ray detector disposed opposite the X-ray source across the object, the X-ray detector outputting a plurality of X-ray images of the object; a control device that performs first CT imaging and second CT imaging to reconstruct the plurality of X-ray images input from the X-ray detector and generate a CT image of the object; The stage is moving in a direction connecting the X-ray source and the X-ray detector; Rotating around a rotation axis perpendicular to the stage, The control device performing a first CT scan and a second CT scan on the object; extracting a collision region indicating a range where the X-ray source and the object may collide from the first CT imaging data; an X-ray CT imaging device that determines an imaging position of the stage relative to the X-ray source when performing a second CT imaging based on the collision region and a region of interest that indicates an observation range in the object;

2. 2. The X-ray CT imaging apparatus according to claim 1, wherein the collision region includes a region through which the object can pass when the object makes one rotation around the rotation axis on the stage.

3. 3. The X-ray CT imaging device according to claim 2, wherein the collision area includes an area obtained by stacking circles perpendicular to the rotation axis and having a radius equal to the distance from the rotation axis to the farthest end of the object for each height from the stage in the direction of the rotation axis.

4. 4. The X-ray CT imaging apparatus according to claim 3, wherein the control device determines the imaging position so that the X-ray image includes the region of interest and the X-ray source is not included in the collision region.

5. 5. The X-ray CT imaging apparatus according to claim 4, wherein the first CT imaging is performed on the entire object in order to extract the collision region.

6. The X-ray CT imaging apparatus according to claim 5 , wherein the second CT imaging is performed on the region of interest of the object placed on the stage at the imaging position.

7. 7. The X-ray CT imaging apparatus according to claim 6, wherein the first CT imaging is performed by rotating the stage at a higher speed than the second CT imaging.

8. The X-ray CT imaging apparatus according to claim 7 , wherein the control device determines the region of interest based on an operation input input by a user.

9. 9. The X-ray CT imaging apparatus according to claim 8, wherein the operation input includes at least one of an imaging range and a magnification.

10. 10. The X-ray CT imaging apparatus according to claim 1, wherein the control device performs the first CT imaging or the second CT imaging based on a start operation from a user.

11. The control device determining a first region and a second region for each range or magnification to be photographed as the region of interest; 11. The X-ray CT imaging apparatus according to claim 10, wherein the second CT imaging for the first region and the second CT imaging for the second region are performed consecutively based on a single start operation from a user.

12. A control method for an X-ray CT imaging apparatus, comprising: The X-ray CT imaging device a stage on which an object is placed; an X-ray source for irradiating the object with X-rays; an X-ray detector disposed opposite the X-ray source across the object, the X-ray detector outputting a plurality of X-ray images of the object; CT imaging is a process of reconstructing the plurality of X-ray images input from the X-ray detector to generate a CT image of the object; The stage is The X-ray source is movable in an X-axis direction connecting the X-ray detector and the X-ray source. The stage is rotatable around a rotation axis perpendicular to the stage, The control method includes: performing a first CT scan on the object; extracting a collision region indicating a range where the X-ray source and the object may collide from the data acquired by the first CT imaging; determining an imaging position of the stage relative to the X-ray source when performing a second CT imaging based on the collision region and a region of interest that indicates an observation range in the object; moving the stage to the imaging position; performing the second CT imaging on the object; and a step of reconstructing and outputting the X-ray image acquired in the second CT imaging.

Images