X-ray phase imaging apparatus and method for displaying preview images in an X-ray phase imaging apparatus

Abstract

To provide an X-ray phase imaging device that, when a plurality of gratings and a subject are relatively rotated and thereby a phase contrast image is photographed, can prevent the relatively rotated subject from being arranged outside a photographing allowable range.SOLUTION: An X-ray imaging device 100 comprises: an X-ray source 1; a detector 4; a plurality of gratings; rotation mechanisms 7, 11 that relatively rotate the plurality of gratings and a subject 90; an image processing unit 5 that creates a phase contrast image 20 from detection signals generated by the X-ray source 1 and the detector 4, and creates a preview image 28 from detection signals generated by the X-ray source 1 and the detector 4 before photographing the phase contrast image 20; and a control unit 6 that performs control of causing a display unit 12 to display the preview image 28 created by the image processing unit 5, and causing the display unit 12 to display, in an identifiable manner, a photographing allowable range 30 of the phase contrast image 20 associated with the relative rotation angle of the plurality of gratings and the subject 90.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to an X-ray phase imaging device and a method for displaying a preview image in an X-ray phase imaging device.

Background Art

[0002] Conventionally, an X-ray phase imaging device including an X-ray source, a plurality of gratings, and a detector has been known (for example, Patent Document 1).

[0003] Patent Document 1 discloses an X-ray imaging system (X-ray phase imaging device) including an X-ray source, a plurality of gratings, a detector, a display unit, a controller (control unit), and an image processing device (image processing unit). Further, Patent Document 1 discloses that the image processing device generates an orientation image representing the orientation of resin and fibers from a dark field image (phase contrast image) generated by the Talbot effect. Further, Patent Document 1 discloses that an orientation image is generated by performing orientation imaging in which the relative angle between the grating and the sample (subject) is changed by rotating a subject table functioning as a rotating stage around a rotation axis along the optical axis.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Although not disclosed in Patent Document 1, a preview image of the subject may be displayed on the display unit of the X-ray phase imaging apparatus before the phase contrast image is captured. Although not disclosed in Patent Document 1, a preview image is an image captured before the phase contrast image is captured under simpler shooting conditions than those for capturing the phase contrast image. Although not disclosed in Patent Document 1, the user can confirm the position of the subject in the preview image displayed on the display unit.

[0006] Here, although not disclosed in Patent Document 1 mentioned above, when orientation imaging is performed by changing the relative rotation angle between the subject and multiple grids from 0 degrees to 45 degrees, the grid support portion may appear along the upper and lower edges of the phase contrast image when the relative rotation angle is 0 degrees. Also, when the relative rotation angle is 45 degrees, the grid support portion may appear tilted at 45 degrees at the four corners of the phase contrast image. In this case, the subject, positioned at the four corners of the preview image when the relative rotation angle is 0 degrees, is within the imaging range and therefore captured in the phase contrast image. However, when the relative rotation angle is 45 degrees, it overlaps with the grid support portion and is outside the imaging range, so it may not be captured in the phase contrast image. Therefore, when multiple grids and a subject are rotated relative to each other to capture a phase contrast image, it is desirable to be able to suppress the positioning of the subject being rotated relative to each other outside the imaging range.

[0007] This invention was made to solve the above-mentioned problems, and one object of this invention is to provide an X-ray phase imaging apparatus and a method for displaying a preview image in an X-ray phase imaging apparatus that can suppress the positioning of a subject being rotated relative to a grid and a subject when a phase contrast image is captured by relatively rotating the subject. [Means for solving the problem]

[0008] The X-ray phase imaging apparatus in the first aspect of this invention comprises an X-ray source, a detector for detecting X-rays irradiated from the X-ray source, a plurality of gratings arranged between the X-ray source and the detector, a rotation mechanism for relatively rotating the plurality of gratings and a subject in a plane perpendicular to the optical axis direction of the X-rays, an image processing unit for generating a phase contrast image from detection signals generated by the X-ray source and the detector, and for generating a preview image from detection signals generated by the X-ray source and the detector before capturing the phase contrast image, and a control unit for displaying the preview image generated by the image processing unit on a display unit, and for displaying on the display unit in an identifiable manner the range in which the phase contrast image can be captured, which is associated with the relative rotation angles between the plurality of gratings and the subject.

[0009] A second aspect of this invention relates to a method for displaying a preview image in an X-ray phase imaging apparatus, comprising an X-ray source, a detector, and a plurality of gratings, the method comprising: generating a preview image from detection signals generated by the X-ray source and the detector before capturing a phase contrast image; displaying the preview image on a display unit; and displaying on the display unit the captureable range of the phase contrast image, which is associated with the relative rotation angles between the plurality of gratings and the subject, in the preview image. [Effects of the Invention]

[0010] The preview image clearly displays the captureable range corresponding to the relative rotation angle, allowing the user to quickly recognize the captureable range of the subject before capturing the phase contrast image. Therefore, when multiple grids and a subject are rotated relative to each other to capture a phase contrast image, it is possible to prevent the rotated subject from being positioned outside the captureable range. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic diagram showing the overall configuration of an X-ray phase imaging apparatus according to one embodiment. [Figure 2] This is a schematic diagram showing an example of a phase contrast image. [Figure 3] This is a schematic diagram showing an example of a CT image. [Figure 4] This is a schematic diagram showing an example of a preview image where the shooting range is not displayed. [Figure 5] This is a schematic diagram showing an example of a preview image displaying the captureable area in 2D image capture mode. [Figure 6] This is a schematic diagram showing an example of a grid rotation mechanism. [Figure 7] This is a schematic diagram showing an example of a grid movement mechanism. [Figure 8] This is an explanatory diagram for illustrating the translational movement of a grid. [Figure 9] This is a schematic diagram of multiple dark-field images and total scattering images captured from multiple angles. [Figure 10] This is an explanatory diagram for describing multiple shooting modes. [Figure 11] This is a schematic diagram illustrating the superimposition of multiple phase contrasts in a 2D image capture mode, with the subject's position fixed. [Figure 12] This is a schematic diagram illustrating the superimposition of multiple phase contrasts in CT image acquisition mode, with the subject's position fixed. [Figure 13] This is a schematic diagram showing an example of a preview image displaying the capture range in CT image acquisition mode. [Figure 14] This is a flowchart illustrating the process for controlling the display of the shooting range. [Figure 15] This is a schematic diagram showing an example of a preview image displaying the shooting range of Modification Example 1. [Figure 16] This is a schematic diagram showing an example of a preview image displaying the shooting range of modified example 2. [Modes for carrying out the invention]

[0012] Hereinafter, embodiments embodying the present invention will be described based on the drawings.

[0013] (Overall Structure of X-ray Phase Imaging Device) Referring to FIG. 1, the overall structure of an X-ray phase imaging device 100 according to an embodiment will be described.

[0014] As shown in FIG. 1, the X-ray phase imaging device 100 is a device that images the interior of a subject 90 using the Talbot effect.

[0015] FIG. 1 is a view of the X-ray phase imaging device 100 as seen from the X direction. As shown in FIG. 1, the X-ray phase imaging device 100 includes an X-ray source 1, a first grating 2, a second grating 3, a detector 4, an image processing unit 5, a control unit 6, a grating rotation mechanism 7, a grating movement mechanism 8, a grating position adjustment mechanism 9, a subject placement unit 10, a rotation mechanism 11, a display unit 12, and a storage unit 13. In this specification, the direction from the X-ray source 1 toward the first grating 2 is defined as the Z2 direction, and the opposite direction is defined as the Z1 direction. Also, the left-right direction within the plane orthogonal to the Z direction is defined as the X direction, the direction toward the back of the paper surface of FIG. 1 is defined as the X2 direction, and the direction toward the front side of the paper surface of FIG. 1 is defined as the X1 direction. Further, the up-down direction within the plane orthogonal to the Z direction is defined as the Y direction, the upward direction is defined as the Y1 direction, and the downward direction is defined as the Y2 direction. Also, the Z direction is an example of the "optical axis direction of X-rays" in the claims. Note that the positional relationships of the control unit 6, the display unit 12, and the storage unit 13 are positional relationships for the sake of illustration and are not limited to the positional relationships in FIG. 1. Also, the first grating 2 and the second grating 3 are examples of the "plurality of gratings" in the claims.

[0016] The X-ray source 1 generates X-rays when a high voltage is applied thereto. The X-ray source 1 is configured to irradiate the generated X-rays in the Z2 direction.

[0017] The first grid 2 has a plurality of slits 2a and X-ray phase shift sections 2b. Each slit 2a and X-ray phase shift section 2b is arranged in the Y direction with a predetermined period (pitch) d1. Each slit 2a and X-ray phase shift section 2b is formed to extend linearly. Also, each slit 2a and X-ray phase shift section 2b is formed to extend parallel to each other. The first grid 2 is a so-called phase grid.

[0018] The first grating 2 is positioned between the X-ray source 1 and the second grating 3, and is irradiated with X-rays from the X-ray source 1. The first grating 2 is provided to form a self-image 91 of the first grating 2 (see Figure 8) due to the Talbot effect. When coherent X-rays pass through the grating with the slit 2a formed therein, an image of the grating (self-image 91) is formed at a predetermined distance (Talbot distance) from the grating. This is called the Talbot effect.

[0019] The second grating 3 has multiple X-ray transmitting sections 3a and X-ray absorbing sections 3b. Each X-ray transmitting section 3a and X-ray absorbing section 3b is arranged in the Y direction with a predetermined period (pitch) d2. Each X-ray transmitting section 3a and X-ray absorbing section 3b is formed to extend in a straight line. Also, each X-ray transmitting section 3a and X-ray absorbing section 3b is formed to extend parallel to each other. The second grating 3 is a so-called absorption grating. The first grating 2 and the second grating 3 are gratings with different roles, but the slit 2a and X-ray transmitting section 3a transmit X-rays, respectively. The X-ray absorbing section 3b shields X-rays. The X-ray phase changing section 2b changes the phase of X-rays due to the difference in refractive index with respect to the slit 2a.

[0020] The second grating 3 is positioned between the first grating 2 and the detector 4, and is irradiated with X-rays that have passed through the first grating 2. The second grating 3 is also positioned at a predetermined Talbot distance from the first grating 2. The second grating 3 interferes with the self-image 91 of the first grating 2, forming moiré fringes on the detection surface of the detector 4.

[0021] Detector 4 is configured to detect X-rays, convert the detected X-rays into electrical signals, and read the converted electrical signals as image signals. Detector 4 is, for example, an FPD (Flat Panel Detector). Detector 4 is composed of multiple conversion elements (not shown) and pixel electrodes (not shown) arranged on the multiple conversion elements. The multiple conversion elements and pixel electrodes are arranged in an array in the X and Y directions at a predetermined period (pixel pitch). Detector 4 is also configured to output the acquired image signal to the image processing unit 5.

[0022] The subject placement unit 10 is positioned between the X-ray source 1 and the detector 4 and is configured to hold the subject 90. The subject 90 may be placed on the subject placement unit 10 via a holder (not shown) or the like for holding the subject 90.

[0023] The image processing unit 5 is configured to generate a phase contrast image 20 (see Figure 2) from the detection signals generated by the X-ray source 1 and the detector 4. The phase contrast image 20 includes an absorption image 21 (see Figure 2), a differential phase image 22 (see Figure 2), and a dark-field image 23 (see Figure 2). In this embodiment, the image processing unit 5 is configured to generate at least the dark-field image 23. Different hatching is applied to each of the absorption image 21, differential phase image 22, and dark-field image 23 to indicate that they are different images.

[0024] Furthermore, the image processing unit 5 is configured to generate a three-dimensional CT (Computed Tomography) image 24 (see Figure 3) from multiple phase contrast images 20 generated by imaging the subject 90, the X-ray source 1, the detector 4, and multiple gratings while relatively rotating them around the second axis 96. The three-dimensional CT image 24 includes an absorption CT image 25 (see Figure 3), a differential phase CT image 26 (see Figure 3), and a dark-field CT image 27 (see Figure 3). In this embodiment, the image processing unit 5 is configured to generate at least a dark-field CT image 27. Note that different hatching is applied to each of the absorption CT image 25, the differential phase CT image 26, and the dark-field CT image 27 to indicate that they are different images.

[0025] A dark-field image is a visibility image obtained by performing phase processing based on the change in visibility due to small-angle scattering of an object. Dark-field images are also called small-angle scattering images. "Visibility" refers to the clarity of the self-image 91. An absorption image is an image obtained by performing phase processing based on the attenuation of X-rays that occurs when X-rays pass through the subject 90. A differential phase image is an image obtained by performing phase processing based on the phase shift of X-rays that occurs when X-rays pass through the subject 90.

[0026] Furthermore, the image processing unit 5 is configured to generate a preview image 28 (see Figure 4) from the detection signals generated by the X-ray source 1 and the detector 4 before the acquisition of the phase contrast image 20. The preview image 28 (see Figure 4) is an image taken before the acquisition of the phase contrast image 20 under simpler acquisition conditions, such as shortening the exposure time or reducing the tube voltage or tube current compared to the acquisition conditions for the phase contrast image 20. The preview image 28 is also a moving image, or fluoroscopic image, obtained by sequentially updating chronologically continuous X-ray images of the subject 90 irradiated with X-rays from the X-ray source 1. The preview image 28 (see Figure 4) may also be a still image obtained by sequentially scanning the X-ray images of the subject 90 irradiated with X-rays from the X-ray source 1. Note that the preview image 28 (see Figure 4) is an image in which moiré fringes (not shown) are visible because no phase processing has been performed by the image processing unit 5.

[0027] The image processing unit 5 includes, for example, a processor such as a GPU (Graphics Processing Unit) or an FPGA (Field-Programmable Gate Array) configured for image processing.

[0028] The control unit 6 is configured to change the angle between the grating and the subject 90 (grating rotation angle) by rotating the grating via the grating rotation mechanism 7. The control unit 6 is also configured to make the first grating 2 movable in the vertical direction (Y direction) or horizontal direction (X direction) within the grating plane via the grating movement mechanism 8. Furthermore, the control unit 6 is configured to rotate the subject 90 around the first axis 95 and the second axis 96 via the rotation mechanism 11, thereby causing relative rotation between the subject 90, the X-ray source 1, the detector 4, and the multiple gratings.

[0029] Furthermore, the control unit 6 is configured to display the preview image 28 generated by the image processing unit 5 on the display unit 12. The control unit 6 is also configured to control the display unit 12 to display the captureable range 30 (see Figure 5) of the phase contrast image 20, which is associated with the relative rotation angles between the multiple grids and the subject 90 (subject placement unit 10) in the preview image 28, in a way that allows for identification. The control by which the control unit 6 displays the captureable range 30 in the preview image 28 in a way that allows for identification will be described later. The control unit 6 includes, for example, a processor such as a CPU (Central Processing Unit).

[0030] The lattice rotation mechanism 7 is configured to rotate the first lattice 2 and the second lattice 3 in a plane perpendicular to the optical axis direction of the X-rays, based on a signal from the control unit 6. The lattice rotation mechanism 7 is provided on the first lattice 2 and the second lattice 3, respectively. The lattice rotation mechanism 7 includes a lattice support part 70 that holds the lattice and a rotation part 71 that rotates the lattice support part 70. The lattice support part 70 supports each of the multiple lattices and rotates relative to the multiple lattices. The lattice rotation mechanism 7 is configured to change the angle between the lattice and the subject 90 by rotating the lattice. Note that the lattice rotation mechanism 7 is an example of a "rotation mechanism" in the claims. The detailed configuration of how the lattice rotation mechanism 7 rotates the lattice will be described later.

[0031] The lattice movement mechanism 8 is configured to move the first lattice 2 in the vertical (Y direction) or horizontal (X direction) direction based on signals from the control unit 6. The vertical direction refers to a position where the lattice is positioned at approximately 90 degrees relative to the horizontal direction (X direction) perpendicular to the X-ray optical axis direction (Z direction). The horizontal direction refers to a position where the lattice is positioned at approximately 0 degrees relative to the horizontal direction (X direction) perpendicular to the X-ray optical axis direction (Z direction). The detailed configuration of how the lattice movement mechanism 8 moves the lattice will be described later. The lattice movement mechanism 8 also holds the lattice rotation mechanism 7 via the lattice position adjustment mechanism 9.

[0032] The grid position adjustment mechanism 9 is configured to adjust the relative position of the first grid 2 between multiple grids based on signals from the control unit 6. A detailed configuration of how the grid position adjustment mechanism 9 adjusts the relative position of multiple grids between grids will be described later.

[0033] The rotation mechanism 11 is configured to rotate the subject 90 (subject mounting section 10), the X-ray source 1, the detector 4, and the multiple gratings relative to each other based on a signal from the control unit 6. The rotation mechanism 11 includes a first rotation mechanism 11a and a second rotation mechanism 11b. The first rotation mechanism 11a includes the subject mounting section 10 on which the subject 90 is placed, and is configured to rotate in a first rotational direction around a first axis 95 that is in the same straight line as the X-ray irradiation axis and passes through the center of the subject mounting section 10 when facing the X-ray source 1. The second rotation mechanism 11b holds the first rotation mechanism 11a and is configured to rotate the first rotation mechanism 11a in a second rotational direction around a second axis 96 that extends in a direction perpendicular to the first axis 95. The rotation mechanism 11 includes a motor and the like. Note that the first rotation mechanism 11a is an example of the "rotation mechanism" in the claims.

[0034] The memory unit 13 stores the program executed by the control unit 6, the two-dimensional phase contrast image 20 and CT image 24 generated by the image processing unit 5, multiple shooting modes A to G, and the shooting range 30 of the phase contrast image 20, which is associated with a relative rotation angle between multiple grids and the subject 90, and which differs for each of the multiple shooting modes. The shooting range 30 is acquired for each phase contrast image that is shot with relative rotation and stored in the memory unit 13. The memory unit 13 includes, for example, an HDD (Hard Disk Drive) or non-volatile memory. In this specification, the relative rotation angle is the angle between the first grid 2 and the second grid 3 and the subject 90 in a plane perpendicular to the optical axis of the X-ray. The relative rotation angle includes the grid rotation angle and the subject rotation angle. The grid rotation angle is the angle between the grid and the subject 90 obtained by rotating the first grid 2 and the second grid 3 by the grid rotation mechanism 7 in the two-dimensional image shooting mode described later. Furthermore, the subject rotation angle refers to the angle between the subject 90 and the grid, which is determined by rotating the subject mounting section 10 by the first rotation mechanism 11a in the CT image acquisition mode described later.

[0035] The display unit 12 displays a preview image 28, controlled by the control unit 6. The display unit 12 includes, for example, a liquid crystal monitor.

[0036] (Grid rotation mechanism, grid movement mechanism, and grid position adjustment mechanism) The configurations of the grid rotation mechanism 7, the grid movement mechanism 8, and the grid position adjustment mechanism 9 will be described with reference to Figures 6 and 7.

[0037] As shown in Figure 6, the grid rotation mechanism 7 includes a grid support portion 70 that holds the grid and a rotation portion 71 that rotates the grid support portion 70. The grid support portion 70 is configured to hold each of the first grid 2 and the second grid 3 internally while in contact with each of them. The grid support portion 70 is also formed in the shape of a disc. Furthermore, the outer circumferential surface of the grid support portion 70 is formed in the shape of a gear.

[0038] The rotating part 71 includes a drive unit (not shown) and a rotating part 71a. The drive unit includes a motor, encoder, etc. The rotating part 71a is formed in the shape of a disc. The outer surface of the rotating part 71a is formed in the shape of a gear. The rotating part 71a is configured to be rotated by the drive unit. In Figure 6, a grid rotation mechanism 7 for rotating the first grid 2 is shown, but the grid rotation mechanism 7 for rotating the second grid 3 has the same configuration as the grid rotation mechanism 7 for rotating the first grid 2.

[0039] As shown in Figure 7, the lattice movement mechanism 8 is configured to move the lattice in the vertical direction (Y direction) or horizontal direction (X direction) within a plane (XY plane) perpendicular to the optical axis direction (Z direction). Specifically, as shown in Figure 7, the lattice movement mechanism 8 includes an X-direction linear motion mechanism 80 and a Y-direction linear motion mechanism 81. The X-direction linear motion mechanism 80 is configured to move translationally in the X direction. The X-direction linear motion mechanism 80 includes, for example, a stepping motor. The Y-direction linear motion mechanism 81 is configured to move translationally in the Y direction. The Y-direction linear motion mechanism 81 includes, for example, a stepping motor. The lattice movement mechanism 8 is configured to move the lattice rotation mechanism 7 in the X direction via the lattice position adjustment mechanism 9 by the operation of the X-direction linear motion mechanism 80. The lattice movement mechanism 8 is also configured to move the lattice rotation mechanism 7 in the Y direction via the lattice position adjustment mechanism 9 by the operation of the Y-direction linear motion mechanism 81. In other words, the grid movement mechanism 8 is configured to move the first grid 2 together with the grid rotation mechanism 7.

[0040] As shown in Figure 7, the grid position adjustment mechanism 9 is held on the grid movement mechanism 8. The grid position adjustment mechanism 9 includes a stage support part 99, a drive unit 97, and a stage 98. The stage support part 99 supports the stage 98 from below (in the Y1 direction). The drive unit 97 is configured to reciprocate the stage support part 99 in the X direction. The stage 98 has a convex curved surface at its bottom facing the stage support part 99, and is configured to rotate around its central axis in the Z direction by reciprocating in the X direction. Unlike the grid rotation mechanism 7, which changes the orientation of each grid by rotating each grid significantly, the grid position adjustment mechanism 9 is a mechanism that adjusts minute angular deviations of the grid within the XY plane.

[0041] (Translation of the grid) Referring to Figure 8, the process by which the control unit 6 translates the grid using the grid movement mechanism 8 will be described. In this embodiment, the image processing unit 5 generates a phase contrast image 20 using the fringe scanning method. The fringe scanning method is a technique for generating an image based on the detected X-ray detection signal curve (step curve) by capturing multiple images while translating the grid by one or more cycles of the grid. In this embodiment, the grid movement mechanism 8 is configured to translate the first grid 2 by one or more cycles (d2) of the second grid 3. The example shown in Figure 6 is a schematic diagram showing the translational movement of the grid when the grid is arranged horizontally (X direction). When the grid is arranged horizontally (X direction), the control unit 6 translates the first grid 2 in the Y2 direction via the grid position adjustment mechanism 9.

[0042] (Generation, synthesis, and orientation color map generation of multiple dark-field images) Referring to Figure 9, the generation, synthesis, and orientation color map generation of multiple dark-field images 23 will be explained.

[0043] The image processing unit 5 is configured to generate a phase contrast image 20 of dark-field images 23 by arranging the grating at multiple angles using the grating rotation mechanism 7 in a plane perpendicular to the optical axis direction of the X-ray beam, thereby generating a plurality of dark-field images 23. The plurality of angles include the grating rotation angle (relative rotation angle) of the grating and the grating rotation angle obtained by rotating the first grating 2 and the second grating 3 by a predetermined angle via the grating rotation mechanism 7. The predetermined angle is, for example, 90 degrees. The number of dark-field images 23 that are arranged at the predetermined angle and the plurality of angles is not particularly limited.

[0044] Furthermore, the image processing unit 5 is configured to synthesize multiple dark-field images 23, which are captured by arranging the grating at multiple angles in a plane perpendicular to the optical axis, to generate a total scattering image 29 that represents the intensity of X-ray scattering by the subject 90. The total scattering image 29 is an image that corresponds to the sum of scattering in each direction obtained by imaging with different grating angles.

[0045] The control unit 6 positions the first grid 2 and the second grid 3 at a relative rotation angle of 0 degrees (X direction) via the grid rotation mechanism 7. The control unit 6 images the subject 90 while translating the first grid 2 via the grid movement mechanism 8. The image processing unit 5 generates a dark-field image 23 of the subject 90.

[0046] Figure 9(A) is a dark-field image 23 taken with the grid positioned at a relative rotation angle of 0 degrees (X direction). In the example shown in Figure 9(A), because the grid is positioned at a relative rotation angle of 0 degrees (X direction), the scratches 93a extending in the X direction among the scratches 93 inside the subject 90 are depicted. The circular area 94 is the impact mark when the subject 90 was struck.

[0047] Next, the control unit 6 rotates the first grid 2 and the second grid 3 by a predetermined angle via the grid rotation mechanism 7, thereby positioning the first grid 2 and the second grid 3 at a relative rotation angle of 90 degrees (Y direction). The control unit 6 images the subject 90 while translating the first grid 2 via the grid movement mechanism 8. The image processing unit 5 generates a dark-field image 23 of the subject 90.

[0048] Figure 9(B) is a dark-field image 23 taken with the grid positioned at a relative rotation angle of 90 degrees (Y direction). In the example shown in Figure 9(B), because the grid is positioned at a relative rotation angle of 90 degrees (Y direction), the scratches 93b extending in the Y direction are depicted among the scratches 93 inside the subject 90. The circular area 94 is the impact mark when the subject 90 was struck.

[0049] Next, the image processing unit 5 generates a total scattering image 29 by combining a dark-field image 23 captured with the grid positioned in the X direction and a dark-field image 23 captured with the grid positioned in the Y direction. The synthesis method can be any known method and is not particularly limited.

[0050] Figure 9(C) is a total scattering image 29 obtained by combining a dark-field image 23 taken with the grid positioned in the X direction and a dark-field image 23 taken with the grid positioned in the Y direction. In the example shown in Figure 9(C), the elliptical region 16 is the region where X-rays scattered in the Y and X directions due to interlayer delamination of the subject 90 were detected.

[0051] Next, the image processing unit 5 generates an orientation color map image (not shown) from the total scattering image 29. The orientation color map image is, for example, an image that represents the orientation of the resin and fibers contained in the subject 90 using color. The orientation color map image can represent the degree of orientation and direction of the resin and fibers contained in the subject 90 for each pixel. Furthermore, the orientation color map image can represent the amount and direction of the resin and fibers contained in the subject 90 for each pixel. The method for generating the orientation color map image is not particularly limited and any known method may be used.

[0052] (Shooting mode) Referring to Figure 10, the multiple shooting modes A to G will be described. In this embodiment, the multiple shooting modes A to G include a two-dimensional image shooting mode that generates a two-dimensional phase contrast image 20, and a CT image shooting mode that generates a two-dimensional phase contrast image 20 and a three-dimensional CT image 24 from the generated phase contrast image 20. The two-dimensional phase contrast image 20 includes at least a dark-field image 23. The three-dimensional CT image includes at least a dark-field CT image 27. The user may select one of the multiple shooting modes A to G before capturing the phase contrast image 20.

[0053] The 2D image capture modes include capture mode A, capture mode B, and capture mode C. In capture mode A, images are captured at a relative rotation angle (grid rotation angle) of 1 between the multiple grids and the subject 90 (subject mounting section 10). For example, the relative rotation angle for capture mode A is 0 degrees. In capture mode B, images are captured at a relative rotation angle (grid rotation angle) of 2 between the multiple grids and the subject 90. For example, the relative rotation angles for capture mode B are 0 degrees and 180 degrees. In capture mode C, images are captured at a relative rotation angle (grid rotation angle) of 4 between the multiple grids and the subject 90. For example, the relative rotation angles for capture mode C are 0 degrees, 45 degrees, 90 degrees, and 135 degrees. Capture mode C is an example of the "first capture mode" in the claims. When generating dark-field images 23 in capture mode C, the image processing unit 5 may generate an orientation color map image based on the multiple dark-field images 23.

[0054] In 2D image acquisition mode, the control unit 6 is configured to change the angle between the grating and the subject 90 in a plane perpendicular to the optical axis of the X-ray by rotating the first grating 2 and the second grating 3 using the grating rotation mechanism 7.

[0055] The CT image acquisition modes include acquisition mode D, acquisition mode E, acquisition mode F, and acquisition mode G. In acquisition mode D, images are acquired at a relative rotation angle of 1 between the multiple grids and the subject 90 (subject mounting section 10). For example, the relative rotation angle for acquisition mode D is 0 degrees. In acquisition mode E, images are acquired at a relative rotation angle of 2 between the multiple grids and the subject 90. For example, the relative rotation angles for acquisition mode E are 0 degrees and 180 degrees. In acquisition mode F, images are acquired at a relative rotation angle of 4 between the multiple grids and the subject 90. For example, the relative rotation angles for acquisition mode F are 0 degrees, 45 degrees, 90 degrees, and 135 degrees. In acquisition mode G, images are acquired at a relative rotation angle of 8 between the multiple grids and the subject 90. As an example, the relative rotation angles for shooting mode G are 0 degrees, 22.5 degrees, 45 degrees, 67.5 degrees, 90 degrees, 112.5 degrees, 135 degrees, and 157.5 degrees. Shooting modes F and G are examples of the "second shooting mode" in the claims. When generating dark-field CT images 27 in shooting modes F and G, the image processing unit 5 may generate an orientation color map image based on a plurality of dark-field images 23.

[0056] In CT image acquisition mode, the control unit 6 is configured to change the angle between the subject 90 and the grid in a plane perpendicular to the optical axis direction of the X-ray by rotating the subject mounting unit 10 with the first rotation mechanism 11a.

[0057] (Control that displays the shooting range in an identifiable manner by the control unit) Referring to Figures 4, 5, and 11-13, the control unit 6 will now describe how to display the identifiable shooting range 30. The control unit 6 displays the identifiable shooting range 30 in shooting mode C of the 2D image acquisition mode, and in shooting modes F and G of the CT image acquisition mode. The control unit 6 is configured to display the identifiable shooting range 30 based on the shooting mode selected by the user.

[0058] The control unit 6 performs a control to display the shooting range 30 in an identifiable manner by superimposing a marker 32 on the preview image 28 that indicates the shooting range 30 of the phase contrast image 20, which is associated with the relative rotation angles between multiple grids and the subject 90 (subject mounting unit 10).

[0059] (Control in shooting mode C of 2D image capture mode) Figure 4 is a schematic diagram showing a preview image 28 with a relative rotation angle (grid rotation angle) of 0 degrees in shooting mode C. In the preview image 28 with a relative rotation angle of 0 degrees, the grid support 70 is visible in the preview image 28 along the upper and lower edges of the preview image 28. The grid support 70 is visible in the preview image 28 due to the relationship between the grid size and the field of view. The area that does not overlap with the position corresponding to the grid support 70 is the shooting range 30. In shooting mode C, shooting is performed when the relative rotation angles between the subject 90 and the multiple grids are 0 degrees, 45 degrees, 90 degrees, and 135 degrees.

[0060] Figure 11 is a schematic diagram illustrating, for ease of explanation, the superimposed phase contrast images 20b (relative rotation angle 45 degrees), 20c (relative rotation angle 90 degrees), and 20d (relative rotation angle 135 degrees) of a phase contrast image 20a (relative rotation angle 0 degrees) with the position of the subject 90 fixed. For ease of explanation, the subject 90 is not shown. Also for ease of explanation, the grid support section 70 with different hatching for each phase contrast image is shown. The position corresponding to the grid support section 70 may differ for each of the multiple phase contrast images captured from four relative rotation angles relative to the subject 90, depending on the relative rotation angles between the multiple grids and the subject 90. That is, the captureable range 30 may also differ for each of the multiple phase contrast images.

[0061] The memory unit 13 (see Figure 1) pre-stores the shooting range 30 of the phase contrast image 20, which is associated with the relative rotation angles (grid rotation angles) between multiple grids and the subject 90 (subject mounting unit 10). The memory unit 13 pre-calculates the positions of the grid support units 70 that appear in the phase contrast image 20 for each of the multiple relative rotation angles, based on the position of the grid support units 70 that appear in the preview image 28 when the relative rotation angle is 0 degrees, and stores them as multiple shooting ranges 30. The memory unit 13 stores the multiple shooting ranges 30, which are associated with the relative rotation angles between the multiple grids and the subject 90. The memory unit 13 stores four shooting ranges 30 for shooting mode C.

[0062] The control unit 6 (see Figure 1) is configured to define the shooting range 30 in shooting mode C as a preset area based on the position of the grid support portion 70 that appears in each of the preview images 28 for each of the four relative rotation angles (grid rotation angles). Furthermore, the control unit 6 is configured to define the shooting range 30 in shooting mode C as the overlapping area of ​​the shooting ranges 30 for each relative rotation angle.

[0063] Figure 5 is a schematic diagram showing a preview image 28 in shooting mode C, where the control unit 6 has performed control to display the shooting range 30 in an identifiable manner. Specifically, as shown in Figure 5(A), the control unit 6 performs control to display the shooting range 30 in an identifiable manner by indicating the shooting range 30 with lines 31. The shooting range 30 in shooting mode C has an octagonal shape. The control unit 6 displays an octagonal frame image as the shooting range 30 in the preview image 28. For convenience of explanation, Figure 5(B) shows the shooting range 30 in the preview image 28 using hatching.

[0064] When the user selects shooting mode C, the control unit 6 displays an octagonal frame image in the preview image 28 based on the shooting range 30 stored in the memory unit 13.

[0065] (Control in CT image acquisition modes F and G) The control in CT image acquisition modes F and G differs from the control in 2D image acquisition mode C in terms of the capture range 30 of the phase contrast image 20, which is associated with the relative rotation angles between the multiple grids and the subject placement unit 10. This point will be explained below, and the control similar to that in 2D image acquisition mode C will not be explained.

[0066] This section describes the capture range 30 of the phase contrast image 20 in CT image acquisition mode G. Figure 12 is a schematic diagram illustrating, for the convenience of explanation, that in CT image acquisition mode G, a phase contrast image 20e with a relative rotation angle (subject rotation angle) of 0 degrees is superimposed with phase contrast images 20f with a relative rotation angle of 22.5 degrees, 20g with a relative rotation angle of 45 degrees, 20h with a relative rotation angle of 67.5 degrees, 20i with a relative rotation angle of 90 degrees, 20j with a relative rotation angle of 112.5 degrees, 20k with a relative rotation angle of 135 degrees, and 20l with a relative rotation angle of 157.5 degrees, with the position of the subject 90 fixed. For the convenience of explanation, the subject 90 is not shown. Also, for the convenience of explanation, a grid support section 70 with different hatching for each phase contrast image is shown. The position corresponding to the grid support portion 70 may differ for each of the multiple phase contrast images captured from eight relative rotation angles with respect to the subject, depending on the relative rotation angle between the multiple grids and the subject 90. In other words, the captureable range 30 may also differ for each of the multiple phase contrast images.

[0067] The memory unit 13 (see Figure 1) pre-stores the shooting range 30 of the phase contrast image 20, which is associated with the relative rotation angles (subject rotation angles) between multiple grids and the subject 90. The memory unit 13 stores four shooting ranges 30 for shooting mode F and eight shooting ranges 30 for shooting mode G.

[0068] The control unit 6 is configured to define the shooting range 30 in shooting mode G as a preset area based on the position of the grid support portion 70 that appears in each of the preview images 28 for each of the eight relative rotation angles (subject rotation angles). Furthermore, the control unit 6 is configured to define the shooting range 30 in shooting mode G as an area based on the overlapping range of the shooting ranges 30 for each relative rotation angle.

[0069] Figure 13 is a schematic diagram showing a preview image 28 in shooting mode G, where the control unit 6 controls the display of the identifiable shooting range 30. Specifically, as shown in Figure 13, the control unit 6 controls the display of the identifiable shooting range 30 by indicating it with a line 31. In shooting mode G, the overlapping area of ​​the shooting range 30 for each relative rotation angle has a hexagonal shape. However, in order to improve the visibility of the shooting range 30 compared to the hexagonal shape, the overlapping area of ​​the shooting range 30 for each relative rotation angle in the shooting of the phase contrast image 20 is set to a circular shape inscribed in the hexagonal shape. The control unit displays a circular frame line in the preview image 28 as the shooting range 30. Note that for the sake of explanation, Figure 13 shows the shooting range 30 in the preview image 28 using hatching.

[0070] In shooting mode F, the overlapping area of ​​the shooting range 30 for each relative rotation angle has an octagonal shape. However, as with shooting mode G, a circular frame inscribed within an octagon is displayed in the preview image 28 as the overlapping area of ​​the shooting range 30 for each relative rotation angle when capturing the phase contrast image 20.

[0071] When the user selects either shooting mode F or shooting mode G, the control unit 6 displays a circular frame image on the preview image 28 based on the shooting range 30 stored in the memory unit 13.

[0072] In addition, in shooting mode A of the 2D image capture mode and shooting mode D of the CT image capture mode, the subject 90 is captured from a relative rotation angle of 1, so the captureable range 30 does not change. Furthermore, in shooting mode B of the 2D image capture mode and shooting mode E of the CT image capture mode, the multiple phase contrast images 20 are captured with their orientation reversed, so the captureable range 30 does not differ for each of the multiple phase contrast images. For this reason, in this embodiment, the control unit 6 is configured not to perform the control to display the captureable range 30 in an identifiable manner in shooting mode A of the 2D image capture mode and shooting mode D of the CT image capture mode.

[0073] (Display control processing for the shooting range) Referring to Figure 14, the display control process for the shooting range 30 according to this embodiment will be explained.

[0074] In step S1, the image processing unit 5 generates a preview image 28 from the detection signals generated by the X-ray source 1 and the detector 4 before acquiring the phase contrast image 20. The processing then proceeds to step S2.

[0075] In step S2, the control unit 6 displays the preview image 28 generated by the image processing unit 5 on the display unit 12. The process then proceeds to step S3.

[0076] In step S3, the control unit 6 determines whether or not an input operation for selecting a shooting mode has been performed. If the control unit 6 determines that an input operation for selecting a shooting mode has been performed (Yes in step S3), the process proceeds to step S4. If the control unit 6 determines that an input operation for selecting a shooting mode has not been performed (No in step S3), the process proceeds to step S3.

[0077] In step S4, the control unit 6 determines whether an input operation has been performed for one of the following selected shooting modes: shooting mode C for 2D image shooting mode, shooting mode F for CT image shooting mode, or shooting mode G for CT image shooting mode. If the control unit 6 determines that an input operation for one of the following has been performed (Yes in step S4), the process proceeds to step S5. If the control unit 6 determines that an input operation for one of the following has not been performed (No in step S4), the process ends.

[0078] In step S5, the control unit 6 displays the identifiable shooting range 30 on the preview image 28 based on the selected shooting mode. After that, the process ends.

[0079] (Effects of this embodiment) In this embodiment, the following effects can be obtained.

[0080] In this embodiment, as described above, the X-ray phase imaging apparatus 100 includes an X-ray source 1, a detector 4 for detecting X-rays irradiated from the X-ray source 1, a plurality of gratings arranged between the X-ray source 1 and the detector 4, rotation mechanisms 7 and 11a for relatively rotating the plurality of gratings and the subject 90 in a plane perpendicular to the optical axis direction of the X-rays, an image processing unit 5 for generating a phase contrast image 20 from detection signals generated by the X-ray source 1 and the detector 4, and for generating a preview image 28 from detection signals generated by the X-ray source 1 and the detector 4 before capturing the phase contrast image 20, and a control unit 6 for displaying the preview image 28 generated by the image processing unit 5 on the display unit 12, and for displaying the captureable range of the phase contrast image 20, which is associated with the relative rotation angles between the plurality of gratings and the subject 90, on the display unit 12 in an identifiable manner. The control unit 6 controls the display unit 12 to display the captureable range 30 of the phase contrast image 20, which is associated with the relative rotation angles between the plurality of gratings and the subject 90, in the preview image 28 in an identifiable manner. As a result, the preview image 28 clearly displays the captureable range 30 corresponding to the relative rotation angle, allowing the user to recognize the captureable range 30 of the subject 90 at a glance before capturing the phase contrast image 20. Therefore, when multiple grids and the subject 90 are rotated relative to each other to capture the phase contrast image 20, it is possible to prevent the subject 90 being rotated relative to each other from being positioned outside the captureable range 30.

[0081] Furthermore, in this embodiment, as described above, the method for displaying the preview image 28 in the X-ray phase imaging apparatus 100 is a method for displaying the preview image 28 in an X-ray phase imaging apparatus 100 comprising an X-ray source 1, a detector 4, and a plurality of gratings, and comprises the steps of: generating a preview image 28 from detection signals generated by the X-ray source 1 and the detector 4 before capturing the phase contrast image 20; displaying the preview image 28 on the display unit 12; and displaying the captureable range of the phase contrast image 20, which is associated with the relative rotation angles between the plurality of gratings and the subject 90, in the preview image 28 in a recognizable manner on the display unit 12. As a result, the captureable range 30 associated with the relative rotation angles is recognizably displayed in the preview image 28, so that the user can recognize the captureable range 30 of the subject 90 at a glance before capturing the phase contrast image 20. Therefore, when the plurality of gratings and the subject 90 are rotated relative to each other to capture the phase contrast image 20, it is possible to suppress the positioning of the subject 90 being rotated relative to each other outside the captureable range 30.

[0082] Furthermore, in the above embodiment, the following additional effects can be obtained by configuring it as follows.

[0083] In other words, in this embodiment, as described above, the control unit 6 performs a control to display the captureable range 30 in an identifiable manner by superimposing a marker 32 indicating the captureable range 30 of the phase contrast image 20, which is associated with the relative rotation angles between the multiple grids and the subject 90, onto the preview image 28. By superimposing the marker 32 indicating the captureable range 30 of the phase contrast image 20, which is associated with the relative rotation angles between the multiple grids and the subject 90, onto the preview image 28, the captureable range 30 in the preview image 28 can be displayed appropriately so that the user can easily recognize it.

[0084] Furthermore, in this embodiment, as described above, the system further includes a plurality of grid support units 70 that support each of the plurality of grids and are rotated relative to the plurality of grids, and the control unit 6 is configured to set the shooting range 30 to a region that is preset based on the position of the relatively rotated grid support units 70 that are captured in the preview image 28. As a result, the shooting range 30 corresponding to the relatively rotated grid support units 70 that are captured in the preview image 28 can be preset, and the shooting range 30 in the preview image 28 can be easily displayed.

[0085] Furthermore, in this embodiment, when multiple phase contrast images 20 are captured while the multiple grids and the subject 90 are rotated relative to each other by the first rotation mechanism 11a as described above, the control unit 6 is configured to set the captureable range 30 to the range where the captureable ranges 30 for each relative rotation angle overlap. This makes it possible to appropriately display the captureable range 30 corresponding to the multiple phase contrast images 20 as the captureable range 30 in the preview image 28 when multiple phase contrast images 20 are captured while the multiple grids and the subject 90 are rotated relative to each other.

[0086] Furthermore, in this embodiment, as described above, the control unit 6 controls the display of the captureable range 30 in the preview image 28 so that it can be identified when the phase contrast image 20 is captured at relative rotation angles of at least 0 degrees, 45 degrees, 90 degrees, and 135 degrees. This ensures that when the phase contrast image 20 is captured at relative rotation angles of at least 0 degrees, 45 degrees, 90 degrees, and 135 degrees, the captureable range 30 corresponding to the four types of phase contrast image 20 can be reliably displayed as the captureable range 30 in the preview image 28.

[0087] Furthermore, in this embodiment, as described above, a storage unit 13 is provided that stores multiple shooting modes and multiple shooting ranges 30 that differ for each of the multiple shooting modes, and the control unit 6 performs control to display the shooting range 30 in an identifiable manner based on the selected shooting mode. As a result, when a shooting mode is selected in which the shooting range 30 may differ for each of the multiple phase contrast images, the shooting range 30 in the preview image 28 can be displayed appropriately.

[0088] Furthermore, in this embodiment, as described above, the multiple shooting modes include shooting mode C, which generates multiple phase contrast images 20 captured at multiple rotation angles while relatively rotating the subject 90, the X-ray source 1 and the detector 4; and shooting modes F and G, which generate multiple phase contrast images 20 captured at multiple rotation angles while relatively rotating the subject mounting unit 10, the X-ray source 1 and the detector 4, and generate a CT image 24 from the generated multiple phase contrast images 20. The shooting range 30 for shooting mode C is octagonal, and the shooting range 30 for shooting modes F and G is circular. This allows the user to easily recognize the shooting range 30, which is configured as octagonal or circular, in the preview image 28.

[0089] Furthermore, in this embodiment, as described above, the control unit 6 performs control to indicate the shooting range 30 with a line 31 as a control to display the shooting range 30 in an identifiable manner. This makes it easier for the user to recognize the shooting range 30 indicated by the line 31 in the preview image 28.

[0090] Furthermore, in this embodiment, as described above, the phase contrast image 20 is a dark-field image 23. This makes it possible to appropriately suppress the positioning of the relatively rotated subject 90 outside the shooting range 30, even when multiple grids and subjects 90 are rotated relative to each other to capture a dark-field image 23.

[0091] [Differentiation] It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims rather than by the description of the embodiments above, and further includes all modifications (exceptions) within the meaning and scope equivalent to the claims.

[0092] For example, in the above embodiment, an example was shown in which a control is performed to show the captureable range 30 of the phase contrast image 20, which is associated with the relative rotation angles of a plurality of grids and a subject 90, as a line 31, by superimposing a marker 32 indicating the captureable range 30 of the phase contrast image 20 onto the preview image 28, but the present invention is not limited thereto. In the present invention, as a control to superimpose a marker 32 indicating the captureable range 30 of the phase contrast image 20, which is associated with the relative rotation angles of a plurality of grids and a subject 90, the captureable range 30 of the phase contrast image 20 may be displayed on the preview image 28 by superimposing the captureable range 30 of the phase contrast image 20, which is associated with a plurality of relative rotation angles, with the areas other than the captureable range filled in black, as shown in Modification 1 in Figure 15.

[0093] Furthermore, while the above embodiment shows an example of controlling the superimposition of a marker 32 indicating the captureable range 30 of the phase contrast image 20, which is associated with the relative rotation angles between a plurality of grids and the subject 90, onto the preview image 28, the present invention is not limited thereto. In the present invention, control may be performed to crop the area outside the region indicating the captureable range 30 in the preview image 28.

[0094] In other words, as shown in the modified example 2 in Figure 16(A), in shooting mode C, where an octagonal shooting range 30 is formed in the preview image 28, the display unit 12 may display a preview image 28 cropped from the outside of the octagonal area representing the shooting range 30. Also, as shown in Figure 16(B), in shooting modes F and G, where a circular shooting range 30 is formed in the preview image 28, the display unit 12 may display a preview image 28 cropped from the outside of the circular area representing the shooting range 30. These methods also allow the shooting range 30 in the preview image 28 to be displayed appropriately.

[0095] Furthermore, in this invention, the control unit 6 is shown as a control that displays the shooting range 30 in an identifiable manner by indicating the shooting range 30 with a line 31, but the present invention is not limited to this. In this invention, as long as the shooting range 30 in the preview image 28 is displayed in an identifiable manner on the display unit 12, the method of displaying the shooting range 30 in the preview image 28 is not particularly limited.

[0096] Furthermore, in the above embodiment, an example was shown in which the control unit 6 is configured to set the shooting range 30 to a region predetermined based on the position corresponding to the grid support portion 70 that appears in the preview image 28, but the present invention is not limited thereto. In the present invention, the control unit 6 may be configured to set the shooting range 30 based on predetermined coordinate values.

[0097] Furthermore, in the above embodiments, shooting was performed in shooting mode C when the relative rotation angles between the subject 90 and the multiple grids were 0 degrees, 45 degrees, 90 degrees, and 135 degrees; in shooting mode F when the relative rotation angles between the subject 90 and the multiple grids were 0 degrees, 45 degrees, 90 degrees, and 135 degrees; and in shooting mode G when the relative rotation angles between the subject 90 and the multiple grids were 0 degrees, 22.5 degrees, 45 degrees, 67.5 degrees, 90 degrees, 112.5 degrees, 135 degrees, and 157.5 degrees. However, the present invention is not limited to these examples. The multiple relative rotation angles in shooting modes C, F, and G only need to be three or more, and the relative rotation angles are not limited to the angles described above.

[0098] Furthermore, in the above embodiment, an example was shown in which the control unit 6 performs control to display the identifiable shooting range 30 in the preview image 28 when shooting mode C, shooting mode F, and shooting mode G are selected, but the present invention is not limited thereto. In the present invention, the control unit 6 may perform control to display the identifiable shooting range 30 in the preview image 28 in any of the selected shooting modes.

[0099] Furthermore, although the above embodiment shows an example in which the shooting range 30 in shooting mode C is configured to be octagonal, the present invention is not limited thereto. In the present invention, it may be a polygonal shape corresponding to the number of relative rotation angles in shooting mode C, or it may be circular. Furthermore, although the above embodiment shows an example in which the shooting range 30 in shooting modes F and G is configured to be circular, the present invention is not limited thereto. In the present invention, it may be a polygonal shape corresponding to the number of relative rotation angles in shooting modes F and G.

[0100] Furthermore, although the above embodiment shows an example in which the plurality of gratings includes a first grating 2 and a second grating 3, the present invention is not limited thereto. In the present invention, the plurality of gratings may further include a third grating positioned between the X-ray source 1 and the first grating 2. This makes it possible to increase the coherence of the X-rays irradiated from the X-ray source 1 by the third grating.

[0101] Furthermore, although the above embodiment shows an example in which the grid movement mechanism 8 translates the first grid 2, the present invention is not limited to this. In the present invention, the grid that is translated can be any grid.

[0102] Furthermore, although the above embodiment shows an example in which the image processing unit 5 is configured to generate at least a dark-field image 23, the present invention is not limited thereto. In the present invention, the image processing unit 5 may not generate a dark-field image 23, but instead generate an absorption image 21 and / or a differential phase image 22.

[0103] Furthermore, although the above embodiment shows an example in which the image processing unit 5 is configured to generate at least a dark-field CT image 27, the present invention is not limited thereto. In the present invention, the image processing unit 5 may not generate a dark-field CT image 27, but instead generate an absorption CT image 25 and / or a differential-phase CT image 26.

[0104] [Aspect] Those skilled in the art will understand that the exemplary embodiments described above are specific examples of the following embodiments.

[0105] (Item 1) X-ray source and, A detector for detecting X-rays irradiated from the aforementioned X-ray source, A plurality of gratings are arranged between the X-ray source and the detector, A rotation mechanism that rotates the plurality of gratings and the subject relative to each other in a plane perpendicular to the optical axis of the X-ray, An image processing unit that generates a phase contrast image from the detection signals generated by the X-ray source and the detector, and generates a preview image from the detection signals generated by the X-ray source and the detector before capturing the phase contrast image, An X-ray phase imaging apparatus comprising: a control unit that causes the preview image generated by the image processing unit to be displayed on a display unit, and controls the display unit to display the captureable range of the phase contrast image, which is associated with the relative rotation angles between the plurality of grids and the subject, in an identifiable manner.

[0106] (Item 2) The X-ray phase imaging apparatus according to item 1, wherein the control unit performs a control to display the imaging range in an identifiable manner by superimposing a marker indicating the imaging range of the phase contrast image, which is associated with the relative rotation angles between the plurality of grids and the subject, onto the preview image, or by cropping out the area outside the region indicating the imaging range in the preview image.

[0107] (Item 3) The system further comprises a plurality of grid support parts that support each of the plurality of grids and are rotated relative to the plurality of grids, The X-ray phase imaging apparatus according to item 1, wherein the control unit is configured to set the imaging range to a region predetermined based on the position of the grid support portion that appears in the preview image.

[0108] (Item 4) The X-ray phase imaging apparatus according to item 1, wherein when multiple phase contrast images are captured while the multiple grids and the subject are rotated relative to each other by the rotation mechanism, the control unit is configured to set the imaging range to the range in which the imaging ranges for each relative rotation angle overlap.

[0109] (Item 5) The X-ray phase imaging apparatus according to item 1, wherein the control unit performs control to display the captureable range in the preview image in an identifiable manner when the phase contrast image is captured at relative rotation angles of at least 0 degrees, 45 degrees, 90 degrees, and 135 degrees.

[0110] (Item 6) The system further includes a storage unit that stores multiple shooting modes and multiple shooting ranges that differ for each of the multiple shooting modes, The X-ray phase imaging apparatus according to item 1, wherein the control unit performs control to display the imaging range in an identifiable manner based on the selected imaging mode.

[0111] (Item 7) The plurality of imaging modes include a first imaging mode that generates a plurality of phase contrast images captured at a plurality of rotation angles while the subject, the X-ray source and the detector are rotated relative to each other, and a second imaging mode that generates a plurality of phase contrast images captured at a plurality of rotation angles while the subject, the X-ray source and the detector are rotated relative to each other, and generates a CT image from the plurality of generated phase contrast images. The X-ray phase imaging apparatus according to item 6, wherein the imaging range of the first imaging mode is octagonal in shape, and the imaging range of the second imaging mode is circular in shape.

[0112] (Item 8) The control unit performs a control that displays the imaging range in an identifiable manner, which is a control that shows the imaging range as a line, according to any one of items 1 to 7, in the X-ray phase imaging apparatus.

[0113] (Item 9) The aforementioned phase contrast image is a dark-field image, and the X-ray phase imaging apparatus is one of the items 1 to 7.

[0114] (Item 10) A method for displaying a preview image in an X-ray phase imaging apparatus comprising an X-ray source, a detector, and a plurality of gratings, Before acquiring a phase contrast image, a step of generating a preview image from the detection signals generated by the X-ray source and the detector, The steps include displaying the preview image on the display unit, A display method comprising the step of displaying on the display unit the range of the phase contrast image that can be captured, which is associated with the relative rotation angles between the plurality of grids and the subject in the preview image. [Explanation of Symbols]

[0115] 1 X-ray source 4 detectors 5 Image Processing Unit 6 Control Unit 7. Grid rotation mechanism 11 Rotation mechanism 12 Display section 13 Storage section 20 Phase contrast image 23 Dark field image 24 CT dementia 27. CT images of dark-field imaging. 28 Preview Images 30 Shooting range 31 lines 32 signs 90 Subjects 100 X-ray phase imaging system

Claims

1. X-ray source and A detector for detecting X-rays irradiated from the aforementioned X-ray source, A plurality of gratings are arranged between the X-ray source and the detector, A rotation mechanism that rotates the plurality of gratings and the subject relative to each other in a plane perpendicular to the optical axis of the X-ray, An image processing unit that generates a phase contrast image from the detection signals generated by the X-ray source and the detector, and generates a preview image from the detection signals generated by the X-ray source and the detector before capturing the phase contrast image, An X-ray phase imaging apparatus comprising: a control unit that causes the preview image generated by the image processing unit to be displayed on a display unit, and controls the display unit to display the captureable range of the phase contrast image, which is associated with the relative rotation angles between the plurality of grids and the subject, in an identifiable manner.

2. The X-ray phase imaging apparatus according to claim 1, wherein the control unit performs a control to display the imaging range in an identifiable manner by superimposing a marker indicating the imaging range of the phase contrast image, which is associated with the relative rotation angles between the plurality of grids and the subject, onto the preview image, or by cropping out the area outside the region indicating the imaging range in the preview image.

3. The system further comprises a plurality of grid support parts that support each of the plurality of grids and are rotated relative to the plurality of grids, The X-ray phase imaging apparatus according to claim 1, wherein the control unit is configured to set the imaging range to a region predetermined based on the position corresponding to the relatively rotated grid support portion that appears in the preview image.

4. The X-ray phase imaging apparatus according to claim 1, wherein, when a plurality of phase contrast images are captured while the plurality of grids and the subject are rotated relative to each other by the rotation mechanism, the control unit is configured to set the imaging range to the range in which the imaging ranges for each relative rotation angle overlap.

5. The X-ray phase imaging apparatus according to claim 1, wherein the control unit performs control to display the captureable range in the preview image in an identifiable manner when the phase contrast image is captured at relative rotation angles of at least 0 degrees, 45 degrees, 90 degrees, and 135 degrees.

6. The system further includes a storage unit that stores multiple shooting modes and multiple shooting ranges that differ for each of the multiple shooting modes, The X-ray phase imaging apparatus according to claim 1, wherein the control unit performs control to display the imaging range in an identifiable manner based on the selected imaging mode.

7. The plurality of imaging modes include a first imaging mode that generates a plurality of phase contrast images captured at a plurality of rotation angles while the subject, the X-ray source and the detector are rotated relative to each other, and a second imaging mode that generates a plurality of phase contrast images captured at a plurality of rotation angles while the subject, the X-ray source and the detector are rotated relative to each other, and generates a CT image from the plurality of generated phase contrast images. The X-ray phase imaging apparatus according to claim 6, wherein the imaging range of the first imaging mode is octagonal in shape, and the imaging range of the second imaging mode is circular in shape.

8. The X-ray phase imaging apparatus according to any one of claims 1 to 7, wherein the control unit performs a control that displays the imaging range in an identifiable manner, by indicating the imaging range with a line.

9. The X-ray phase imaging apparatus according to any one of claims 1 to 7, wherein the phase contrast image is a dark-field image.

10. A method for displaying a preview image in an X-ray phase imaging apparatus comprising an X-ray source, a detector, and a plurality of gratings, Before acquiring a phase contrast image, a step of generating a preview image from the detection signals generated by the X-ray source and the detector, The steps include displaying the preview image on the display unit, A display method comprising the step of displaying on the display unit the range of the phase contrast image that can be captured, which is associated with the relative rotation angles between the plurality of grids and the subject in the preview image.

Images