X-ray photography device

Abstract

The X-ray imaging device (100) comprises an imaging unit (2), a moving mechanism (4), and an image processing unit (17) for generating an image of a subject (42). The image processing unit is configured to set an imaging area, i.e., a reference plane (34), when generating an image of the subject, and to generate an image of the subject in the reference plane. The image processing unit is configured to determine the pixel value of the pixel corresponding point by selecting the pixel corresponding to the pixel corresponding point in the X-ray image that most clearly captures the pixel corresponding point when there are multiple X-ray images that capture the pixel corresponding point.

Description

Technical Field

[0001] The present invention relates to an X-ray imaging apparatus, and more particularly to an X-ray imaging apparatus that generates an image of a subject based on images captured at a plurality of imaging positions. Background Art

[0002] Conventionally, there is known an X-ray imaging apparatus that generates an image of a subject based on images captured at a plurality of imaging positions. For example, Japanese Patent Application Laid-Open No. 2004-57506 discloses such an X-ray imaging apparatus.

[0003] Japanese Patent Application Laid-Open No. 2004-57506 discloses an X-ray imaging apparatus comprising: a top plate for placing a subject; an X-ray tube for irradiating the subject with X-rays; an X-ray detector; and a vertically movable frame for holding the X-ray tube and the X-ray detector. The vertically movable frame disclosed in Japanese Patent Application Laid-Open No. 2004-57506 is mounted on ceiling rails or floor rails and is configured to move the X-ray tube and the X-ray detector in a direction along the subject's body axis.

[0004] The X-ray imaging device disclosed in Japanese Patent Application Laid-Open No. 2004-57506 is configured to capture multiple X-ray images while moving a vertically movable frame. The X-ray imaging device disclosed in Japanese Patent Application Laid-Open No. 2004-57506 is configured to capture multiple X-ray images with overlapping portions. The X-ray imaging device disclosed in Japanese Patent Application Laid-Open No. 2004-57506 is configured to generate a single long image by gluing together the overlapping portions of the multiple X-ray images. This long image is particularly useful in surgeries such as administering contrast agents to identify narrowed areas or bifurcations in lower limb blood vessels, which cannot be accommodated in a single X-ray image and require a large displacement of the imaging range.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2004-57506 Summary of the Invention

[0008] Problems to be solved by the invention

[0009] Here, as disclosed in Japanese Patent Application Laid-Open No. 2004-57506, Figure 1As shown in the figure, X-rays are emitted radially from an X-ray tube. Therefore, depending on the position of the X-ray tube when the X-ray images are taken, the incident angle of the X-rays may differ in the overlapping portions of the X-ray images. When the incident angles of the X-rays differ, parallax occurs in the overlapping portions of the X-ray images. In this case, if the overlapping portions are joined to generate a long image (object image), the joined portion becomes unnatural, making it difficult to generate a smooth object image.

[0010] The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to provide an X-ray imaging apparatus capable of generating a smooth subject image even when generating a subject image based on a plurality of images captured while changing the imaging position.

[0011] Solutions for solving problems

[0012] To achieve the above-mentioned object, an X-ray imaging apparatus according to one aspect of the present invention comprises: an imaging unit including an X-ray source for irradiating X-rays toward a subject and an X-ray detecting unit for detecting X-rays transmitted through the subject, the imaging unit being configured to capture images; a moving mechanism including a top plate on which the subject is placed, the mechanism being capable of moving at least one of the top plate and the imaging unit so as to change the relative position between the top plate and the imaging unit; and an image processing unit acquiring a plurality of images while changing the relative position using the moving mechanism, and generating an image of the subject based on the plurality of images, wherein the image processing unit is configured to set an imaging region, i.e., a reference plane, when generating an image of the subject, based on the plurality of images, and to determine pixel values ​​of respective plurality of points included in the reference plane based on the plurality of images, thereby generating an image of the subject in the reference plane, and wherein the image processing unit is configured to, when there are a plurality of images capturing a point, select a pixel corresponding to the point in the image that captures the point most clearly among the plurality of images, thereby determining the pixel value of the point.

[0013] Effects of the Invention

[0014] In one aspect of the present invention, an X-ray imaging apparatus includes an image processing unit, as described above, configured to set a reference plane, an imaging region for generating an image of a subject, based on multiple images, and to determine pixel values ​​for each of multiple pixel-corresponding points included in the reference plane based on the multiple images, thereby generating an image of the subject on the reference plane. Furthermore, when multiple images capture a pixel-corresponding point, the image processing unit is configured to determine the pixel value of the pixel-corresponding point by selecting the pixel corresponding to the pixel-corresponding point within the image that most clearly captures the pixel-corresponding point among the multiple images. Thus, the pixel value of each pixel-corresponding point on the reference plane is selected from the pixel corresponding to the pixel-corresponding point within the image that most clearly captures the pixel-corresponding point among the multiple images. Therefore, the subject image can be generated based on the pixel value selected from the pixel corresponding to each pixel-corresponding point on the reference plane. Thus, unlike a configuration in which overlapping portions of multiple images are combined to generate a subject image, the subject image can be generated using the most optimal pixel value without adding the pixel values ​​of multiple pixels. As a result, it is possible to provide an X-ray imaging apparatus capable of generating a smooth subject image even when generating a subject image based on a plurality of images captured while changing the imaging position. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram showing the overall structure of an X-ray imaging apparatus according to one embodiment.

[0016] Figure 2 This is a block diagram showing the overall configuration of an X-ray imaging apparatus according to one embodiment.

[0017] Figure 3 It is a schematic diagram for explaining the imaging positions of a plurality of X-ray images.

[0018] Figure 4 This is a schematic diagram for explaining a configuration for generating an image of a subject based on a plurality of X-ray images.

[0019] Figure 5 This is a schematic diagram for explaining which pixel is selected as a pixel for determining the pixel value of the pixel corresponding point on the reference plane when the same pixel is included in a plurality of X-ray images.

[0020] Figure 6 This is a schematic diagram for explaining a reference plane when the detection surface of the X-ray detection unit is arranged parallel to the top plate.

[0021] Figure 7 This is a schematic diagram for explaining how the incident angle of X-rays incident on a point corresponding to the same pixel changes due to relative movement between the imaging unit and the top plate.

[0022] Figure 8 This is a schematic diagram for explaining a reference plane when the detection surface of the X-ray detection unit is arranged in a state of being inclined with respect to the top plate.

[0023] Figure 9 This is a schematic diagram for explaining the direction in which the pixel corresponding point on the reference plane moves when the top plate is moved in a state in which the imaging unit is tilted relative to the top plate.

[0024] Figure 10 Schematic diagram for explaining a plurality of images captured in the top plate coordinate system.

[0025] Figure 11 This is a schematic diagram for explaining a structure for converting the coordinates of each pixel of a plurality of images into three-dimensional coordinates.

[0026] Figure 12 This is a flowchart for explaining a process of generating a subject image by the X-ray imaging apparatus according to one embodiment.

[0027] Figure 13 Schematic diagram for explaining the structure of selecting pixel values ​​of pixel corresponding points on a reference plane in the first modification example.

[0028] Figure 14 It is a schematic diagram for explaining a plurality of imaging positions along an arbitrary movement path according to the second modification.

[0029] Figure 15 This is a schematic diagram for explaining a configuration of generating a subject image based on a plurality of images captured along an arbitrary movement path according to a second modification.

[0030] Figure 16 This is a schematic diagram for explaining the rotation of the C-arm when capturing a plurality of images in the X-ray imaging apparatus according to the third modified example.

[0031] Figure 17 This is a schematic diagram for explaining the movement of the top plate when capturing a plurality of images in the X-ray imaging apparatus according to the third modified example.

[0032] Figure 18 This is a schematic diagram for explaining the rotation of the C-arm when capturing a plurality of images in the X-ray imaging apparatus according to the fourth modified example.

[0033] Figure 19 This is a schematic diagram for explaining the movement of the top plate when capturing a plurality of images in the X-ray imaging apparatus according to the fourth modified example.

[0034] Figure 20 Schematic diagram for explaining the distance between the pixel corresponding to the pixel corresponding point on the reference plane and the center of each image according to the fifth modification.

[0035] Figure 211 is a schematic diagram for explaining a configuration of selecting an image including pixels corresponding to pixel corresponding points on a reference plane according to a fifth modification example.

[0036] Figure 22 Schematic diagram showing the overall structure of an X-ray imaging apparatus according to a sixth modification.

[0037] Figure 23 This is a block diagram showing the overall configuration of an X-ray imaging apparatus according to a sixth modification.

[0038] Figure 24 This is a flowchart for explaining a process of generating a subject image by the X-ray imaging apparatus according to the sixth modification. DETAILED DESCRIPTION

[0039] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0040] Reference Figures 1 to 11 The structure of the X-ray imaging apparatus 100 according to one embodiment will be described.

[0041] (Structure of X-ray Radiography Apparatus)

[0042] like Figure 1 As shown, the X-ray imaging apparatus 100 of this embodiment includes a top plate 1 , an imaging unit 2 , a rotation mechanism 3 , a movement mechanism 4 , a control unit 5 , a display unit 6 , a storage unit 7 , and an operation unit 8 .

[0043] The subject 30 is placed on the top plate 1. The top plate 1 is formed into a rectangular flat plate when viewed from above. The subject 30 is placed on the top plate 1 in such a manner that the head and feet direction of the subject 30 is along the long side of the top plate 1 and the left and right direction of the subject 30 is along the short side of the top plate 1. In addition, in this specification, the long side of the top plate 1 is set as the X direction. In addition, the short side direction of the top plate 1 is set as the Y direction. In addition, the direction orthogonal to the X direction and the Y direction is set as the Z direction. In addition, the head and feet direction of the subject 30 is the direction along the straight line connecting the head and feet of the subject 30.

[0044] The imaging unit 2 includes an X-ray source 9 and an X-ray detection unit 10. The imaging unit 2 is configured to capture X-ray images (X-ray image 40a, X-ray image 40b, X-ray image 40c, and X-ray image 40d) (see Figure 4 ). The X-ray source 9 is arranged on one side in the Z direction relative to the top plate 1. The X-ray source 9 is configured to irradiate the subject 30 with X-rays by applying voltage to an X-ray tube driving unit (not shown). In addition, the X-ray source 9 has a collimator 11 that can adjust the irradiation range of the X-rays, that is, the X-ray irradiation field. In addition, the X-ray source 9 is configured as follows: Figure 1As shown, it is attached to the front end of one side of the C-arm 12. In addition, an X-ray image is an example of an "image" in the present application.

[0045] The X-ray detection unit 10 is configured to detect X-rays irradiated from the X-ray source 9 and transmitted through the subject 30. The X-ray detection unit 10 includes, for example, an FPD (Flat Panel Detector). The X-ray detection unit 10 is mounted on the front end of the other side of the C-arm 12 (the side opposite to the X-ray source 9). In addition, the C-arm 12 is arranged in a position where the front end portions sandwich the top plate 1. That is, the X-ray detection unit 10 is arranged on the other side of the top plate 1 (the side opposite to the X-ray source 9) across the top plate 1. Thus, the X-ray imaging device 100 is configured to be able to capture X-ray images by irradiating X-rays with the X-ray source 9 in a state where the subject 30 is placed on the top plate 1 and detecting X-rays that have transmitted through the subject 30 with the X-ray detection unit 10. In addition, the X-ray detection unit 10 is configured to be able to detect X-rays in the direction in which the sliding unit 13 extends (in the direction in which the sliding unit 13 extends) through the sliding unit 13 mounted on the front end of the C-arm 12. Figure 1 Slide upward (Z direction).

[0046] The rotation mechanism 3 is configured to rotate the imaging unit 2 by rotating the C-arm 12 under the control of the control unit 5. The rotation mechanism 3 includes a movement mechanism that moves the C-arm 12 along the outer periphery of the C-arm 12. The rotation mechanism 3 is configured to rotate the C-arm 12 about an axis in the longitudinal direction (X direction) of the top plate 1 and about an axis in the transverse direction (Y direction) of the top plate 1. The rotation mechanism 3 includes, for example, a motor.

[0047] The moving mechanism 4 includes a top plate 1 on which the subject 30 is placed. In addition, the moving mechanism 4 includes a C-arm 12 that integrally holds the X-ray source 9 and the X-ray detection unit 10. The moving mechanism 4 is configured to be able to move at least one of the top plate 1 and the imaging unit 2 under the control of the control unit 5 to change the relative position of the top plate 1 and the imaging unit 2. Specifically, the moving mechanism 4 is configured to be able to move the top plate 1 in any one of the X direction, the Y direction, and the Z direction to change the relative position of the top plate 1 and the imaging unit 2. The moving mechanism 4 includes a direct-acting mechanism that can move in the X direction, a direct-acting mechanism that can move in the Y direction, and a direct-acting mechanism that can move in the Z direction. Each direct-acting mechanism includes, for example, a ball screw, a linear motor, and the like.

[0048] In addition, in this embodiment, the moving mechanism 4 includes a top plate holding portion 4a that holds the top plate 1 so that the top plate 1 can be manually moved at least within a plane. Therefore, in this embodiment, the top plate 1 can be automatically moved by the moving mechanism 4 and can also be manually moved by an operator.

[0049] The control unit 5 is configured to control the rotation mechanism 3 to rotate the imaging unit 2. Furthermore, the control unit 5 is configured to control the movement mechanism 4 to move the top plate 1 and the imaging unit 2 relative to each other. The control unit 5 is a computer configured to include a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory). Furthermore, the control unit 5 includes an image information acquisition unit 14, a rotation angle acquisition unit 15, a position information acquisition unit 16, and an image processing unit 17. Furthermore, the control unit 5 is configured to function as the image information acquisition unit 14, the rotation angle acquisition unit 15, and the position information acquisition unit 16 by executing various programs stored in the storage unit 7. Specifically, the image information acquisition unit 14, the rotation angle acquisition unit 15, and the position information acquisition unit 16 are processing blocks of the programs executed by the control unit 5.

[0050] The image information acquisition unit 14 is as follows Figure 2 As shown, the image information captured by the imaging unit 2 is acquired from the X-ray detection unit 10. The image information acquired by the image information acquisition unit 14 is stored in the storage unit 7. The image information acquired by the image information acquisition unit 14 is used by the image processing unit 17 to generate an X-ray image.

[0051] The rotation angle acquiring unit 15 is as follows: Figure 2 As shown in FIG. 1 , the rotation angle 51 of the photographing unit 2 rotated by the rotation mechanism 3 is obtained (see FIG. 1 ). Figure 8 ). In addition, the rotation angle 51 of the imaging unit 2 is the vertical direction and the optical axis 22 of the X-ray (refer to Figure 8 ) is the angle formed by the

[0052] The position information acquisition unit 16 is as follows: Figure 2 As shown, the position information of the top plate 1 moved by the moving mechanism 4 is obtained. The position information of the top plate 1 includes coordinate information (X, Y, Z) at predetermined positions of the top plate 1. For example, the position information of the top plate 1 includes coordinate information (X, Y, Z) at any position near the four corners of the top plate 1. In this way, the position information obtaining unit 16 uses the coordinate information of the top plate 1 as the position information of the top plate 1 to obtain the amount of movement of the top plate 1 when the top plate 1 is relatively moved.

[0053] The image processing unit 17 is as follows Figure 2As shown in FIG. 1 , the image processing unit 17 is configured to generate an X-ray image based on the image information acquired by the image information acquisition unit 14. Specifically, the image processing unit 17 is configured to acquire a plurality of X-ray images while changing the relative position by the moving mechanism 4, and to generate an X-ray image based on the plurality of X-ray images (X-ray image 40a, X-ray image 40b, X-ray image 40c, and X-ray image 40d) (see FIG. Figure 4 ) to generate the subject image 42 (refer to Figure 4 The image processing unit 17 includes, for example, a GPU (Graphics Processing Unit) or an FPGA (Field-Programmable Gate Array) configured for image processing. The detailed structure of the image processing unit 17 generating the subject image 42 will be described later.

[0054] The display unit 6 is configured as, for example, a liquid crystal display. The display unit 6 is configured to display an X-ray image generated by the image processing unit 17 based on the image information captured by the imaging unit 2. The display unit 6 is also configured to display a subject image 42 generated by the image processing unit 17 based on the X-ray image.

[0055] The storage unit 7 includes, for example, an HDD (Hard Disk Drive) and a non-volatile memory. The storage unit 7 stores programs used in the processing of the rotation mechanism 3, the movement mechanism 4, the image information acquisition unit 14, the rotation angle acquisition unit 15, the position information acquisition unit 16, and the image processing unit 17. Furthermore, the storage unit 7 is configured to store image information captured by the imaging unit 2, the rotation angle 51 of the imaging unit 2 acquired by the rotation angle acquisition unit 15, the position information of the top plate 1 acquired by the position information acquisition unit 16, the X-ray image generated by the image processing unit 17, and the subject image 42 generated by the image processing unit 17. Furthermore, the storage unit 7 can be connected to the X-ray imaging apparatus 100 either by wire or by wireless. Furthermore, the storage unit 7 can be connected to the X-ray imaging apparatus 100 via a network and thus be located in a location away from the X-ray imaging apparatus 100.

[0056] The operation unit 8 includes, for example, a mouse and a keyboard. The operation unit 8 is configured to receive input operations from an operator and to transmit the received input operations to the control unit 5.

[0057] (Method of Generating Subject Image)

[0058] Next, refer to Figures 3 to 5 The configuration of the image processing unit 17 generating the subject image 42 will be described.

[0059] The X-ray imaging apparatus 100 of this embodiment is configured to be able to move the top plate 1 by the moving mechanism 4 or manually at a plurality of imaging positions (a first imaging position 21a, a second imaging position 21b, a third imaging position 21c, and a fourth imaging position 21d) of the subject 30 (see Figure 3 Specifically, by moving the top plate 1 relative to the imaging unit 2 in the X and Y directions, as shown in FIG. Figure 3 In this embodiment, the image information acquiring unit 14 acquires image information obtained by performing X-ray photography, and the position information acquiring unit 16 acquires position information of the top plate 1. In addition, in this embodiment, a plurality of X-ray images (X-ray image 40a, X-ray image 40b, X-ray image 40c, and X-ray image 40d) (see Figure 4 ) is an image of a contrast agent injected into the subject 30. Specifically, the X-ray image includes an image of the blood vessels 33 of the lower limb portion 32 of the subject 30. In addition, the subject image 42 is also an X-ray image of the blood vessels 33 of the lower limb portion 32 of the subject 30.

[0060] In this embodiment, X-ray images are taken at a plurality of imaging positions. Figure 3 For convenience, the following example is shown: X-ray images (X-ray image 40a, X-ray image 40b, X-ray image 40c, and X-ray image 40d) are captured at four of the multiple imaging positions at which the X-ray imaging apparatus 100 captures X-ray images: the first imaging position 21a, the second imaging position 21b, the third imaging position 21c, and the fourth imaging position 21d. Furthermore, in this embodiment, the multiple X-ray images are captured at a collection rate that suppresses parallax, which is caused by the movement of the same pixel between the multiple X-ray images due to the movement of the top plate 1, to a level that is difficult to visually recognize. The collection rate is, for example, 7.5 fps (Frame Per Second).

[0061] like Figure 4 As shown in FIG, the image processing unit 17 generates X-ray images obtained by performing X-ray imaging at a plurality of imaging positions based on image information obtained by performing X-ray imaging. Figure 4 In the example shown, the image processing unit 17 generates X-ray images 40a, 40b, 40c, and 40d captured at the first imaging position 21a to the fourth imaging position 21d. In addition, the image processing unit 17 is configured to set the imaging area when generating the subject image 42, that is, the reference plane 34 (see FIG. 1 ). Figure 6). In addition, the image processing unit 17 is configured to generate the subject image 42 in the reference plane 34 by determining the pixel values ​​of each of the plurality of pixel corresponding points (pixel corresponding point 35a, pixel corresponding point 35b, pixel corresponding point 35c, and pixel corresponding point 35d) included in the reference plane 34 based on the X-ray image. In the present embodiment, the subject image 42 in the reference plane 34 is generated by determining based on a plurality of X-ray images. In other words, each pixel corresponding point (pixel corresponding point 35a, pixel corresponding point 35b, pixel corresponding point 35c, and pixel corresponding point 35d) of the reference plane 34 is each pixel (pixel 43a, pixel 43b, pixel 43c, and pixel 43d) of the subject image 42.

[0062] exist Figure 4 In the example shown, for convenience, the case where pixel corresponding points 35a, 35b, 35c, and 35d (pixels 43a, 43b, 43c, and 43d of the subject image 42) of the reference plane 34 are selected is shown. When there is only one X-ray image in which pixels corresponding to the pixel corresponding points are captured, the image processing unit 17 generates the subject image 42 by selecting the pixel values ​​of the pixels of the X-ray image in which the pixel corresponding points are captured. Specifically, Figure 4 As shown, the image processing unit 17 generates the subject image 42 by selecting the pixel values ​​of pixels (pixel 41a, pixel 41b, pixel 41c and pixel 41d) corresponding to each pixel corresponding point (pixel corresponding point 35a, pixel corresponding point 35b, pixel corresponding point 35c and pixel corresponding point 35d) of the reference plane 34.

[0063] Furthermore, when there are multiple X-ray images that capture pixels corresponding to the corresponding pixel point, the image processing unit 17 is configured to determine the pixel value of the corresponding pixel point by selecting the pixel corresponding to the corresponding pixel point within the X-ray image that captures the pixel corresponding to the corresponding pixel point most clearly among the multiple X-ray images (X-ray image 40a, X-ray image 40b, X-ray image 40c, and X-ray image 40d). The pixel that captures the corresponding pixel point most clearly means that the difference (contrast) between the pixel value of the pixel corresponding to the corresponding pixel point and the pixel value of the background portion is the largest.

[0064] (When there are multiple X-ray images of points on the reference surface)

[0065] Next, refer to Figure 5 Next, when there are multiple X-ray images that capture the pixel corresponding point of the reference plane 34 , which X-ray image includes a pixel value that is selected as the pixel value of the pixel corresponding point of the reference plane 34 will be described.

[0066] like Figure 5 As shown, X-ray images 40a, 40b, 40c, and 40d include pixels corresponding to pixel corresponding point 35b of reference plane 34 (pixel 43b of subject image 42). In each X-ray image (X-ray images 40a to 40d), pixel 41a, pixel 41b, pixel 41c, and pixel 41d correspond to pixel corresponding point 35b of reference plane 34.

[0067] In this embodiment, when there are multiple X-ray images that capture the corresponding pixel point, the image processing unit 17 is configured to determine the pixel value of the corresponding pixel point by selecting the pixel value of the pixel closest to the center of the X-ray image, which is the pixel that most clearly captures the corresponding pixel point among the pixels corresponding to the pixel point on the reference plane 34 within the multiple X-ray images. Furthermore, the pixel at the center of the X-ray image is the pixel at which X-rays enter the corresponding pixel point on the reference plane 34 at a 90-degree angle of incidence. Therefore, the closer the pixel is to the center of the X-ray image, the less blurring the image will experience due to X-rays entering at an oblique angle, resulting in the pixel corresponding to the corresponding pixel point being the clearest in the X-ray image.

[0068] (reference plane)

[0069] Next, refer to Figures 6 to 9 The reference surface 34 will be described. Figure 6 and Figure 7 This is an example of a case where the detection surface 10a of the X-ray detection unit 10 is arranged in parallel with the top plate 1. Figure 8 and Figure 9 This is an example of a case where the detection surface 10 a of the X-ray detection unit 10 is arranged in a state of being inclined with respect to the top plate 1 .

[0070] <When the imaging unit is arranged parallel to the top plate>

[0071] First, refer to Figure 6 and Figure 7 The reference plane 34 when the detection surface 10 a of the X-ray detection unit 10 is arranged parallel to the top plate 1 will be described.

[0072] like Figure 6As shown, the reference plane 34 is a plane along the detection plane 10a of the X-ray detection unit 10. In addition, the reference plane 34 is a plane. In addition, the plane along the detection plane 10a of the X-ray detection unit 10 refers to a plane parallel to the detection plane 10a of the X-ray detection unit 10. In addition, the reference plane 34 is an imaging area when generating the subject image 42 based on multiple X-ray images, and is set based on the sizes of each of the multiple X-ray images. In addition, with respect to the reference plane 34, the height of the area to be imaged is determined by setting the height position from the top plate 1. The height position is set by the user to an arbitrary position. For example, the height position is set by the user to a position such as +10 cm based on the point where the irradiated X-rays are concentrated, that is, the isocenter.

[0073] Here, if Figure 7 As shown in FIG. 1 , the X-rays emitted from the X-ray source 9 are radiated in a manner that expands radially before reaching the X-ray detection unit 10. Figure 7 In the example shown, the solid line 70 shows the direction of the first imaging position 21a (see FIG. Figure 3 ) irradiated with X-rays. In addition, the single-dot chain line 71 illustrates the X-rays irradiated to the second imaging position 21b (refer to Figure 3 ) . Furthermore, the optical axis 22 of each X-ray is shown by a dotted line. When imaging is performed while moving the imaging unit 2, there is a case where X-rays emitted from different imaging positions are incident on the same pixel corresponding point 35a on the reference plane 34.

[0074] like Figure 7 As shown, when X-rays (solid line 70) emitted from the first imaging position 21a and X-rays (single-dot chain line 71) emitted from the second imaging position 21b are incident on the same pixel corresponding point 35a on the reference plane 34, the angles of incidence of each X-ray are different. In this case, the X-ray image based on one X-ray becomes a state of looking up at the pixel corresponding point 35a, and the X-ray image based on the other X-ray becomes a state of looking down at the pixel corresponding point 35a. Therefore, when the respective X-ray images are joined, the joined portion becomes unnatural, and the image quality of the subject image 42 deteriorates. Therefore, in this embodiment, the image processing unit 17 is configured to generate the subject image 42 by selecting the pixel value of the pixel corresponding point 35a on the reference plane 34 as the pixel value of the pixel of the X-ray image. In addition, the state of looking up at the pixel corresponding point 35a refers to a state in which the pixel corresponding point 35a is located on the traveling direction side relative to the optical axis 22 of the X-ray. In addition, the state of looking down at the pixel corresponding point refers to the state in which the pixel corresponding point 35a is located on the opposite side to the traveling direction with respect to the optical axis 22 of the X-ray. Figure 7In the example of , the X-ray image based on the X-ray irradiated to the first imaging position 21a becomes a state of looking up at the pixel corresponding point 35a. In addition, the X-ray image based on the X-ray irradiated to the second imaging position 21b becomes a state of looking down at the pixel corresponding point 35a. Figure 7 In the example shown, the pixel corresponding point 35 a is used for description, but the same applies to other pixel corresponding points.

[0075] <When the imaging unit is arranged in a tilted state relative to the top plate>

[0076] Next, refer to Figure 8 and Figure 9 The reference surface 34 in the case where the detection surface 10 a of the X-ray detection unit 10 is arranged in a tilted state with respect to the top plate 1 will be described.

[0077] Figure 8 By using the rotating mechanism 3 (refer to Figure 6 ) An example of rotating the photographing unit 2 around the Y direction to tilt the photographing unit 2 relative to the top plate 1. Figure 8 As shown, the rotation mechanism 3 is configured to tilt the imaging unit 2 from the vertical by an angle 51, thereby tilting the angle 50 formed between the optical axis 22 of the X-rays emitted from the X-ray source 9 and the longitudinal direction (X-direction) of the top plate 1. Specifically, the angle 50 formed between the optical axis 22 of the X-rays emitted from the X-ray source 9 and the longitudinal direction (X-direction) of the top plate 1 is 90 degrees when the angle 50 formed between the optical axis 22 of the X-rays emitted from the X-ray source 9 and the longitudinal direction (X-direction) of the top plate 1 is added to the rotation angle 51 of the imaging unit 2. Therefore, increasing either the rotation angle 51 of the imaging unit 2 or the angle 50 formed between the optical axis 22 of the X-rays emitted from the X-ray source 9 and the longitudinal direction (X-direction) of the top plate 1 decreases the other. Furthermore, tilting the angle 50 formed between the optical axis 22 of the X-rays emitted from the X-ray source 9 and the longitudinal direction (X-direction) of the top plate 1 refers to a state where the angle 50 formed between the optical axis 22 of the X-rays emitted from the X-ray source 9 and the longitudinal direction (X-direction) of the top plate 1 is an angle other than 0 degrees, 90 degrees, or 180 degrees within the range of 0 to 180 degrees.

[0078] like Figure 8 As shown, even when the imaging unit 2 is tilted relative to the top plate 1, the reference surface 34 is a plane along the detection surface 10a of the X-ray detection unit 10. Figure 8 As shown, the reference surface 34 is in a tilted state relative to the top plate 1 .

[0079] Here, if Figure 9As shown, when the photographic unit 2 is configured in a tilted state relative to the top plate 1, when the top plate 1 is moved along the direction of arrow 60, the pixel corresponding point 35a on the reference plane 34 moves in the direction of arrow 61. The direction along arrow 61 can be decomposed into the X direction and the Z direction as shown by arrows 62 and 63. That is, when the top plate 1 is moved in the X direction while the photographic unit 2 is tilted relative to the top plate 1, the pixel corresponding point 35a on the reference plane 34 moves in the X direction and also moves in the Z direction. When the Z direction is moved, movement in the direction of the optical axis 22 of the X-ray is also generated, so the magnification in the X-ray image changes. Therefore, when the photographic unit 2 is photographed in a tilted state relative to the top plate 1, each X-ray image (X-ray image 40a, X-ray image 40b, X-ray image 40c, and X-ray image 40d) becomes an image with different magnifications. In addition, in Figure 9 In the example shown, the pixel corresponding point 35 a is used for description, but the same applies to other pixel corresponding points.

[0080] Therefore, in this embodiment, when the imaging unit 2 is arranged in a tilted state relative to the top plate 1, the reference plane 34 is set to a plane having the same magnification ratio for each of the plurality of X-ray images. In other words, in this embodiment, the image processing unit 17 is configured to select pixel values ​​corresponding to corresponding points of each pixel on the reference plane 34 from the plurality of X-ray images after changing the magnification ratios of the plurality of X-ray images so that the subject 30 captured in each of the X-ray images (X-ray image 40a, X-ray image 40b, X-ray image 40c, and X-ray image 40d) is the same size.

[0081] (Coordinate Transformation of X-ray Images)

[0082] Next, refer to Figure 10 and Figure 11 The configuration of the image processing unit 17 for performing coordinate conversion of the X-ray image will be described.

[0083] Figure 10 The example shown shows a top plate coordinate system (XYZ coordinate system). The top plate coordinate system is a coordinate system in which the XY plane is a plane 36 parallel to the top plate 1, and the direction perpendicular to the XY plane is the Z direction. The relative position of the top plate 1 and the imaging unit 2 is managed in the top plate coordinate system. With respect to the top plate coordinate system, the directions of the XYZ coordinate axes remain unchanged within the X-ray imaging apparatus 100.

[0084] Figure 11The example shown shows a three-dimensional coordinate system (PQR coordinate system). With respect to the three-dimensional coordinate system, the RP plane is the plane of the image when the X-ray image is generated, and the Q direction is the depth direction. In other words, the RP plane is the plane along the detection surface 10a of the X-ray detection unit 10, that is, the reference plane 34, and the Q direction is the direction of the optical axis 22 of the X-ray. The three-dimensional coordinate system is a coordinate system (camera coordinate system) for defining the reference plane 34, and the direction of each coordinate axis of PQR can be arbitrarily changed according to the reference plane 34. In this embodiment, the reference plane 34 is parallel to the detection surface 10a, so the three-dimensional coordinate system is set according to the orientation of the X-ray detection unit 10 (the angle of the C-arm 12). By the coordinate transformation between the top plate coordinate system and the three-dimensional coordinate system, it is determined at which pixel of the X-ray image the X-ray that has passed through which pixel corresponding point of the reference plane 34 is detected.

[0085] In this embodiment, the image processing unit 17 transforms the coordinates of the pixels of multiple X-ray images from the top plate coordinate system (XYZ coordinate system) into a three-dimensional coordinate system (PQR coordinate system). The image processing unit 17 transforms the coordinates of the top plate coordinate system into a three-dimensional coordinate system through matrix transformation, based on, for example, the angle of the C-arm 12 and the position information of the top plate 1 when each X-ray image was captured. Furthermore, the Q coordinates after the coordinate transformation are coordinates in the direction of the X-ray optical axis 22. Therefore, the Q coordinates of each X-ray image after the coordinate transformation by the image processing unit 17 are unified, and thus the magnification of each X-ray image is unified.

[0086] In addition, the photographing unit 2 is in a state where it is not tilted relative to the top plate 1 (see Figure 6 ), the magnification does not change in each X-ray image (X-ray image 40a, X-ray image 40b, X-ray image 40c, and X-ray image 40d) captured at multiple imaging positions (first imaging position 21a, second imaging position 21b, third imaging position 21c, and fourth imaging position 21d). However, when the X-ray irradiation angle is 90 degrees, points in the subject 30 with the same X and Y coordinates but different Z coordinates appear at the same position on the XY plane. However, when X-rays are irradiated from an oblique direction, points in the subject 30 with the same X and Y coordinates but different Z coordinates appear at different positions on the XY plane. Therefore, even when the imaging unit 2 is not tilted relative to the top plate 1, the image processing unit 17 performs coordinate transformation on the X-ray image when selecting pixels for determining pixel values ​​corresponding to pixel points on the reference plane 34, thereby obtaining X-ray images for all pixels corresponding to pixel corresponding points. In addition, in this embodiment, the image processing unit 17 performs coordinate transformation on each pixel in the multiple X-ray images.

[0087] Next, refer to Figure 12The following describes a process of generating the subject image 42 by the X-ray imaging apparatus 100 according to this embodiment.

[0088] In step 101, the image processing unit 17 obtains X-ray images (X-ray image 40a, X-ray image 40b, X-ray image 40c, and X-ray image 40d) captured at multiple imaging positions (first imaging position 21a, second imaging position 21b, third imaging position 21c, and fourth imaging position 21d) while moving the top plate 1.

[0089] Next, in step 102 , the image processing unit 17 sets the reference plane 34 based on the plurality of X-ray images.

[0090] Next, in step 103, the image processing unit 17 transforms the coordinates of each pixel (pixel 41a, pixel 41b, pixel 41c, and pixel 41d) of the plurality of X-ray images. Furthermore, a reference plane 34 is set so that the magnification of each X-ray image is uniform. Therefore, when the coordinates of the X-ray images captured at each imaging position are transformed onto the reference plane 34 of the three-dimensional coordinate system, the X-ray images captured at each imaging position are aligned so that the magnification of each X-ray image is uniform.

[0091] Next, in step 104 , the image processing unit 17 selects pixels corresponding to each pixel corresponding point on the reference plane 34 based on the plurality of X-ray images after coordinate transformation, and determines the pixel value of each pixel corresponding point.

[0092] Next, in step 105, the image processing unit 17 determines whether the pixel values ​​of all the corresponding points on the reference surface 34 have been determined. If the pixel values ​​of all the corresponding points on the reference surface 34 have been determined, the process proceeds to step 106. If the pixel values ​​of all the corresponding points on the reference surface 34 have not been determined, the process proceeds to step 104.

[0093] In step 106, the image processing unit 17 generates the subject image 42. Thereafter, the processing ends.

[0094] (Effects of this embodiment)

[0095] In this embodiment, the following effects can be obtained.

[0096] In the present embodiment, as described above, there are provided: an imaging unit 2 including an X-ray source 9 for irradiating X-rays toward a subject 30 and an X-ray detection unit 10 for detecting X-rays that have passed through the subject 30, the imaging unit 2 being used to capture X-ray images; a moving mechanism 4 including a top plate 1 on which the subject 30 is placed, the moving mechanism 4 being configured to move at least one of the top plate 1 and the imaging unit 2 so as to change the relative position between the top plate 1 and the imaging unit 2; and an image processing unit 17 for acquiring a plurality of X-ray images (X-ray image 40a, X-ray image 40b, X-ray image 40c, and X-ray image 40d) while changing the relative position using the moving mechanism 4, and An object image 42 is generated based on multiple X-ray images, wherein the image processing unit 17 is configured to set an imaging area when generating the object image 42, i.e., a reference plane 34, based on the multiple X-ray images, and determine the pixel values ​​of each of the multiple pixel corresponding points contained in the reference plane 34 based on the multiple X-ray images, thereby generating the object image 42 in the reference plane 34. The image processing unit 17 is configured to determine the pixel value of the pixel corresponding point by selecting the pixel corresponding to the pixel in the X-ray image that captures the pixel corresponding point most clearly among the multiple X-ray images when there are multiple X-ray images that capture the pixel corresponding point.

[0097] With the above configuration, the pixel values ​​of each pixel-corresponding point (pixel-corresponding point 35a, pixel-corresponding point 35b, pixel-corresponding point 35c, and pixel-corresponding point 35d) on the reference plane 34 are selected from the pixel corresponding to the pixel-corresponding point within the image in which the pixel-corresponding point is most clearly captured among the multiple X-ray images (X-ray image 40a, X-ray image 40b, X-ray image 40c, and X-ray image 40d). Therefore, the subject image 42 can be generated based on the pixel value selected from the pixel corresponding to each pixel-corresponding point on the reference plane 34. Therefore, unlike a configuration in which the subject image 42 is generated by joining the overlapping portions of multiple X-ray images, the subject image 42 can be generated based on the optimal pixel value without adding the pixel values ​​of multiple pixels. As a result, an X-ray imaging apparatus 100 can be provided that can generate a smooth subject image 42 even when generating the subject image 42 based on multiple X-ray images captured while changing the imaging position.

[0098] Furthermore, in this embodiment, as described above, the image processing unit 17 is configured to determine the pixel value of a pixel corresponding point by selecting the pixel value of the pixel that most clearly captures the pixel corresponding point from among the pixels corresponding to the pixel corresponding point on the reference plane 34 in the multiple X-ray images (X-ray image 40a, X-ray image 40b, X-ray image 40c, and X-ray image 40d), and the pixel value of the pixel corresponding point. This allows the selection of pixels located at positions with minimal distortion in the X-ray images as pixels corresponding to each pixel corresponding point (pixel corresponding point 35a, pixel corresponding point 35b, pixel corresponding point 35c, and pixel corresponding point 35d). As a result, a smooth subject image 42 can be easily generated.

[0099] Furthermore, in this embodiment, as described above, the reference plane 34 is a plane that is aligned with the detection plane 10a of the X-ray detector 10. Thus, even when a doctor or the like performs imaging with the imaging unit 2 tilted, for example, a subject image 42 aligned with the intended plane can be generated. As a result, the degree of freedom in the placement of the imaging unit 2 when imaging the subject 30 can be increased, thereby improving user convenience.

[0100] In the present embodiment, as described above, the reference plane 34 is a flat surface. This allows the subject image 42 to be generated as a planar image of a surface that a doctor or the like wishes to confirm.

[0101] In addition, in this embodiment, as described above, the moving mechanism 4 further includes a top plate holding portion 4a that holds the top plate 1 in a manner that allows manual movement of the top plate 1 at least within a plane. This allows the top plate 1 to be moved at any speed, unlike a structure that automatically moves the top plate 1. As a result, for example, when a doctor or the like moves the top plate 1 while tracking the blood flow in the blood vessels 33 of the lower limb 32 (blood flow at different speeds depending on the subject 30) to perform imaging, the top plate 1 can be moved at a speed that corresponds to the blood flow speed that varies among individual subjects 30.

[0102] Furthermore, in this embodiment, as described above, the moving mechanism 4 further includes a C-arm 12 that integrally holds the X-ray source 9 and the X-ray detector 10. Thus, by changing the angle of the C-arm 12, imaging can be performed while the imaging unit 2 (X-ray source 9 and X-ray detector 10) is tilted relative to the table 1. As a result, even if the blood vessel 33 to be observed is located below a bone, for example, imaging can be performed from an oblique angle to allow the blood vessel 33 to be identified in the subject image 42.

[0103] [Modification]

[0104] In addition, it should be understood that the embodiments disclosed this time are illustrative in all aspects and are not restrictive. The scope of the present invention is not shown by the description of the above embodiments, but by the claims, and also includes all changes (modifications) within the meaning and scope equivalent to the claims.

[0105] (First Modification)

[0106] For example, in the above embodiment, the following configuration example is shown: when there are multiple X-ray images that capture the pixel corresponding point, the image processing unit 17 selects the pixel value of the pixel closest to the center of the X-ray image as the pixel value of the pixel corresponding point on the reference plane 34, but the present invention is not limited to this. Figure 13 As shown, the image processing unit 17 can also be configured to: when there are multiple X-ray images that capture the pixel corresponding point, select the pixel value of the pixel that captures the pixel corresponding point most clearly among the pixels corresponding to the pixel corresponding point in the multiple X-ray images (X-ray image 40a, X-ray image 40b, X-ray image 40c and X-ray image 40d) and has the highest concentration of contrast agent, thereby determining the pixel value of the pixel corresponding point.

[0107] Figure 13 It is a schematic diagram showing an example of a pixel 41e corresponding to a pixel corresponding point 35e of a reference plane 34 (a pixel 43e of a subject image 42) captured in a plurality of X-ray images (X-ray image 40a, X-ray image 40b, X-ray image 40c, and X-ray image 40d). The image processing unit 17 determines the pixel value of the pixel with the highest concentration of contrast agent in the pixel 41e of each X-ray image as the pixel value of the pixel corresponding point. In addition, the image processing unit 17 standardizes the background portion in the X-ray image and performs a relative comparison of the pixel values ​​of the contrast agent (blood vessel 33), thereby selecting the pixel with the highest concentration of the contrast agent. In addition, when the X-ray irradiated from the X-ray source 9 does not change, the image processing unit 17 may also be configured to select a pixel with a low pixel value of a pixel of the X-ray image as the pixel with the highest concentration of the contrast agent. In addition, in Figure 13 In the example shown, the difference in the contrast medium concentration is expressed by the difference in the interval between hatching lines. Specifically, the smaller the interval between hatching lines, the higher the contrast medium concentration.

[0108] With the above configuration, the image processing unit 17 selects the pixel value of the pixel with the highest contrast agent concentration when there are multiple X-ray images that capture the corresponding pixel point. Therefore, the pixel value of the pixel that most clearly captures the blood vessel 33 can be selected as the pixel value of the corresponding pixel point on the reference plane 34. As a result, the subject image 42 is generated based on the pixel values ​​of the most clearly captured pixels within the multiple X-ray images (X-ray image 40a, X-ray image 40b, X-ray image 40c, and X-ray image 40d). Therefore, the subject image 42 can be generated in which the blood vessel 33 is clearly depicted.

[0109] (Second Modification)

[0110] In addition, in the above embodiment, the following configuration example is shown: the image processing unit 17 generates the subject image 42 based on the plurality of X-ray images (X-ray image 40a, X-ray image 40b, X-ray image 40c, and X-ray image 40d) captured while the top plate 1 is moved only in the X direction, but the present invention is not limited to this. For example, Figure 14 As shown in the second modification, the image processing unit 17 is configured to: based on a plurality of X-ray images (X-ray image 400a, X-ray image 400b, X-ray image 400c, X-ray image 400d, X-ray image 400e, X-ray image 400f, X-ray image 400g, and X-ray image 400h) acquired while being manually moved along an arbitrary movement path (see Figure 15 ) to generate a long strip image 420 as an image of the subject along the movement path in the reference plane 34.

[0111] In the second modification, Figure 14 As shown, the top plate 1 is moved along an arbitrary movement path indicated by arrow 64 to a plurality of imaging positions while imaging is performed. Specifically, the top plate 1 is moved along arrow 64 to a first imaging position 210a, a second imaging position 210b, a third imaging position 210c, a fourth imaging position 210d, a fifth imaging position 210e, a sixth imaging position 210f, a seventh imaging position 210g, and an eighth imaging position 210h while imaging is performed. In addition to the configuration in which imaging is performed while the top plate 1 is moved along an arbitrary movement path, for example, a doctor or the like may also manually grasp a grip portion (not shown) of the imaging unit 2 to move the imaging unit 2 along an arbitrary movement path while imaging is performed. In addition, for example, a doctor or the like may also operate the operating unit 8 to move the top plate 1 or the imaging unit 2 along an arbitrary movement path while imaging is performed.

[0112] like Figure 15As shown, a plurality of X-ray images 400a, 400b, 400c, 400d, 400e, 400f, 400g, and 400h are captured at respective imaging positions (a first imaging position 210a, a second imaging position 210b, a third imaging position 210c, a fourth imaging position 210d, a fifth imaging position 210e, a sixth imaging position 210f, a seventh imaging position 210g, and an eighth imaging position 210h). The image processing unit 17 generates a strip image 420 as an image of the subject along the movement path from the plurality of X-ray images using the same method as in the above-described embodiment.

[0113] The image processing unit 17 selects the pixel value of each pixel corresponding to the reference plane 34 based on the plurality of X-ray images (X-ray image 400a, X-ray image 400b, X-ray image 400c, X-ray image 400d, X-ray image 400e, X-ray image 400f, X-ray image 400g, and X-ray image 400h), thereby generating a long image 420 as an image of the subject. In addition, the arbitrary movement path is not limited to Figure 14 The moving mechanism 4 is configured to be able to move the top plate 1 arbitrarily in any of the X, Y, and Z directions. Therefore, the moving path can be any path formed by combining the X, Y, and Z directions.

[0114] If constructed as described above, even when the top plate 1 is moved along an arbitrary path, a long strip image 420 can be generated as an image of the subject, thereby increasing the freedom of choice in the movement path. As a result, even when a doctor or the like moves the imaging unit 2 in an arbitrary direction while tracing the blood flow in the blood vessels 33 of the lower limbs, a long strip image 420 can be generated as an image of the subject, thereby increasing user convenience. In addition, in the example of the lower limbs, depending on the patient, there are cases where the lower limbs are kept bent and cannot be extended. Even in this case, imaging along the bent lower limbs can be performed without registering the movement path in advance. Furthermore, by generating a long strip image 420 projected onto the reference plane 34 for each X-ray image (X-ray image 400a, X-ray image 400b, X-ray image 400c, X-ray image 400d, X-ray image 400e, X-ray image 400f, X-ray image 400g, and X-ray image 400h) captured along an arbitrary path, the influence of parallax generated in any direction can be effectively removed to generate an image with high visibility.

[0115] (Third Modification)

[0116] Furthermore, in the above embodiment, the image processing unit 17 generates the subject image 42 based on a plurality of X-ray images (X-ray image 40a, X-ray image 40b, X-ray image 40c, and X-ray image 40d) captured while the top plate 1 is moved with the angle of the C-arm 12 fixed. However, the present invention is not limited thereto. For example, the image processing unit 17 may be configured to generate a single subject image 42 based on a plurality of X-ray images captured by rotating the C-arm 12 while the top plate 1 is moved using the moving mechanism 4.

[0117] Figure 16 : is a schematic diagram of the C-arm 12 when imaging in the X-ray imaging apparatus 100 according to the third modified example, as viewed from the X direction. Figure 17 1 is a schematic diagram of the C-arm 12 viewed from the Y direction during imaging in the X-ray imaging apparatus 100 according to the third modified example.

[0118] like Figure 16 As shown in FIG. 3 , in the third modified example, the X-ray imaging apparatus 100 takes a plurality of X-ray images while changing the rotation angle of the C-arm 12. Figure 17 As shown in FIG. 3 , in the third modified example, the X-ray imaging apparatus 100 takes a plurality of X-ray images while moving the top plate 1. Specifically, Figure 16 and Figure 17 As shown, multiple X-ray images are taken when the rotation angle of the C-arm 12 is the first rotation angle 121a and the position of the top plate 1 is the fifth photographic position 21e, the rotation angle of the C-arm 12 is the second rotation angle 121b and the position of the top plate 1 is the sixth photographic position 21f, the rotation angle of the C-arm 12 is the third rotation angle 121c and the position of the top plate 1 is the seventh photographic position 21g, and the rotation angle of the C-arm 12 is the fourth rotation angle 121d and the position of the top plate 1 is the eighth photographic position 21h.

[0119] That is, in the third modified example, the X-ray imaging device 100 is configured to capture a plurality of X-ray images while rotating the C-arm 12 and moving the top plate 1 in parallel. Furthermore, the rotation angle of the C-arm 12 refers to the angle formed by the optical axis 22 of the X-ray and the Z direction. Furthermore, the rotation angle of the C-arm 12 is not limited to four angles. The rotation angle of the C-arm 12 may be more or less than four angles. Furthermore, the position of the top plate 1 is not limited to four places. The position of the top plate 1 may be more or less than four places. The rotation angle of the C-arm 12 and the position of the top plate 1 are arbitrarily set by the user.

[0120] With the above configuration, even when multiple blood vessels overlap in the Z direction, for example, the angle of the C-arm 12 can be changed for imaging. This allows imaging of multiple blood vessels that overlap in the Z direction from an oblique angle. Consequently, the subject image 42 is generated based on multiple X-ray images captured at different imaging angles. Therefore, even when imaging blood vessels that overlap in the Z direction, a subject image 42 that allows identification of each blood vessel can be generated.

[0121] (Fourth Modification)

[0122] Furthermore, in the above embodiment, the image processing unit 17 generates the subject image 42 based on a plurality of X-ray images (X-ray image 40a, X-ray image 40b, X-ray image 40c, and X-ray image 40d) captured while the top plate 1 is moved with the angle of the C-arm 12 fixed. However, the present invention is not limited thereto. For example, the image processing unit 17 may be configured to generate a plurality of subject images 42 at various angles based on X-ray images captured at the same rotation angle of the C-arm 12, among a plurality of X-ray images captured while the top plate 1 is moved by the moving mechanism 4 and the C-arm 12 is rotated.

[0123] Figure 18 : is a schematic diagram of the C-arm 12 when imaging in the X-ray imaging apparatus 100 according to the fourth modification example, as viewed from the X direction. Figure 19 1 is a schematic diagram of the C-arm 12 viewed from the Y direction during imaging in the X-ray imaging apparatus 100 according to the fourth modified example.

[0124] like Figure 18 As shown in FIG. 3 , in the third modification, the X-ray imaging apparatus 100 captures a plurality of X-ray images while changing the rotation angle of the C-arm 12. Figure 18 In the example shown, a plurality of X-ray images are captured while the rotation angle of the C-arm 12 is changed to the fifth rotation angle 121e, the sixth rotation angle 121f, and the seventh rotation angle 121g. Figure 19 As shown, in the fourth modification, the X-ray imaging apparatus 100 captures a plurality of X-ray images while moving the top plate 1 to the fifth to eighth imaging positions 21 e to 21 h .

[0125] In the fourth modification, Figure 19When the top board 1 is moved as shown, the C-arm 12 is rotated at various positions of the top board 1 to capture X-ray images at multiple rotation angles. Specifically, with the top board 1 positioned at the fifth imaging position 21e, the C-arm 12 is rotated to the fifth, sixth, and seventh rotation angles 121f, 121g, to capture X-ray images. Similarly, at the sixth, seventh, and eighth imaging positions 21f, 21g, and 21h, the C-arm 12 is rotated to the fifth, seventh, and seventh rotation angles 121e, 121g, to capture X-ray images.

[0126] That is, the action of taking X-ray images while rotating the C-arm 12 is performed alternately with the movement of the top plate 1, thereby obtaining a group of multiple X-ray images corresponding to the rotation angle of the C-arm 12, with the same rotation angle of the C-arm 12 and different positions of the top plate 1. The image processing unit 17 generates multiple subject images 42 based on the multiple X-ray images with the same rotation angle of the C-arm 12. In addition, Figure 18 In the example shown, the C-arm 12 is arranged at three angles and imaging is performed, but the rotation angles of the C-arm 12 are not limited to Figure 18 The angles shown are shown. It is also possible to perform imaging while rotating the C-arm 12 to three or more angles. Furthermore, the position of the top plate 1 is not limited to four. The position of the top plate 1 may be more or less than four. The rotation angles of the C-arm 12 and the position of the top plate 1 are arbitrarily set by the user.

[0127] With the above configuration, it is possible to generate subject images 42 at multiple imaging angles based on X-ray images captured from multiple imaging angles by a single administration of contrast agent. As a result, when performing imaging at multiple imaging angles, the number of administrations of contrast agent can be reduced compared to a configuration in which contrast agent is administered each time imaging at each imaging angle is performed, thereby reducing the burden on the subject 30. Furthermore, compared to a configuration in which imaging at multiple imaging angles is performed separately for each angle, an increase in imaging time can be suppressed.

[0128] (Fifth Modification)

[0129] In addition, in the above embodiment, the image processing unit 17 selects the pixel values ​​of the pixels at the positions close to the center of the X-ray image when selecting the pixel values ​​of the pixel corresponding points of the reference plane 34, but the present invention is not limited thereto. For example, a configuration may be adopted in which the pixel values ​​of the pixels at the positions close to the center of the X-ray image are selected. Figure 20 ) in the pixel corresponding point 35a (refer to Figure 21 ) corresponding pixels (pixel 41a, pixel 41b and pixel 41c) (refer to Figure 20 ) When the distances from the center position of the X-ray image are equal to each other, the pixel values ​​of the corresponding points of the pixels of the reference plane 34 are selected based on the distances between the reference plane 34 and the pixels in each X-ray image in the three-dimensional coordinate system.

[0130] Figure 20 This is a diagram for explaining the pixel corresponding point 35a (see FIG. 1 ) of the reference plane 34 in the plurality of X-ray images (X-ray image 40a, X-ray image 40b, and X-ray image 40c). Figure 21 ) is a schematic diagram of the distances (distance d1, distance d2, and distance d3) between the pixels corresponding to the pixel corresponding point 35a of the reference plane 34 (pixel 41a, pixel 41b, and pixel 41c) and the center of each X-ray image. In the X-ray image 40a, the X-ray image 40b, and the X-ray image 40c, the positions of the pixels corresponding to the pixel corresponding point 35a of the reference plane 34 are different from each other. However, in each X-ray image, the distances (distance d1, distance d2, and distance d3) between the pixels corresponding to the pixel corresponding point 35a of the reference plane 34 and the center of the image are equal to each other. In the fifth modification, in such a case, the image processing unit 17 is configured to select the pixel value of the pixel corresponding point 35a of the reference plane 34 based on the three-dimensional distance between each pixel (pixel 41a, pixel 41b, and pixel 41c) and the reference plane 34.

[0131] Here, when the top plate 1 is moved while the reference plane 34 is tilted relative to the top plate 1, the position of the same pixel corresponding point 35a of the reference plane 34 in the Z direction changes. If the position of the pixel corresponding point 35a in the Z direction changes, the magnification changes. In other words, it can be considered that the distances between each X-ray image (X-ray image 40a, X-ray image 40b, and X-ray image 40c) of the pixel corresponding to the pixel corresponding point 35a of the reference plane 34 and the reference plane 34 are different. That is, as Figure 21 As shown, it can be considered that the plurality of X-ray images in which the pixel corresponding point 35 a is captured are located at different positions in the Z direction. Figure 21 Schematic diagram showing the distances between the X-ray image 40a, the X-ray image 40b, and the X-ray image 40c and the reference plane 34. Figure 21 In the example shown, distance d4 is the smallest among distances d4 between X-ray image 40a and reference plane 34, distance d5 between X-ray image 40b and reference plane 34, and distance d6 between X-ray image 40c and reference plane 34. Therefore, image processing unit 17 selects the pixel value of pixel 41a in X-ray image 40a as the pixel value of pixel-corresponding point 35a on reference plane 34.

[0132] With the above configuration, the pixel value of pixel 41a located three-dimensionally closest to reference plane 34 can be selected as the pixel value of pixel corresponding point 35a on reference plane 34. This reduces the effects of image distortion caused by the X-ray irradiation angle, thereby preventing the generated subject image 42 from becoming unnatural. Furthermore, even when there are multiple pixels at equal distances from the center of the X-ray image, the pixel 41a that most clearly captures pixel corresponding point 35a can be easily determined.

[0133] (Sixth Modification)

[0134] In addition, in the above embodiment, a configuration example in which a single imaging unit 2 is used to image the subject 30 is shown, but the present invention is not limited thereto. Figure 22 As shown, the imaging unit 2 may include a first imaging unit 2a and a second imaging unit 2b, wherein the second imaging unit 2b captures a plurality of X-ray images (X-ray image 40a, X-ray image 40b, X-ray image 40c, and X-ray image 40d) while being tilted at a different angle than the first imaging unit 2a relative to the subject 30. In the figures, the same reference numerals are assigned to the same components as those in the above-described embodiment.

[0135] like Figure 22 As shown, the X-ray imaging device 100 of the sixth modified example can also be configured as a so-called dual-plane X-ray imaging device, in which the imaging unit 2 includes a first imaging unit 2a and a second imaging unit 2b, wherein the second imaging unit 2b captures a plurality of X-ray images while being tilted at an angle different from that of the first imaging unit 2a relative to the subject 30. The first imaging unit 2a is arranged at a position across the top plate 1 in the Z direction. In addition, the second imaging unit 2b is arranged at a position across the top plate 1 in the Y direction. In addition, in the X-ray imaging device 100 of the sixth modified example, the rotating mechanism 3 includes a first rotating mechanism 3a capable of rotating the first imaging unit 2a and a second rotating mechanism 3b capable of rotating the second imaging unit 2b.

[0136] The first imaging unit 2a includes an X-ray source 9 and an X-ray detection unit 10. Furthermore, the second imaging unit 2b includes an X-ray source 24 and an X-ray detection unit 25. The X-ray source 24 includes a collimator 28. The X-ray source 24, the X-ray detection unit 25, and the collimator 28 are identical in structure to the X-ray source 9, the X-ray detection unit 10, and the collimator 11 of the first embodiment, respectively, and therefore detailed descriptions thereof are omitted.

[0137] The first rotation mechanism 3 a has the same structure as the rotation mechanism 3 of the above-described embodiment, and therefore detailed description thereof will be omitted.

[0138] The second rotating mechanism 3b holds the second imaging unit 2b via the C-arm 26. The second rotating mechanism 3b is configured to rotate the second imaging unit 2b by rotating the C-arm 26. The second rotating mechanism 3b includes a moving mechanism that moves the C-arm 26 along the outer periphery of the C-arm 26. Furthermore, the second rotating mechanism 3b is held by a moving mechanism 27 mounted on the ceiling 90. The moving mechanism 27 is configured to move the second rotating mechanism 3b in the X-direction. Furthermore, the moving mechanism 27 is configured to rotate the second rotating mechanism 3b about the axis of the straight line 45.

[0139] like Figure 23 As shown, in the sixth modification, the image information acquisition unit 14 is configured to acquire image information captured by the first imaging unit 2a from the X-ray detection unit 10. Furthermore, the image information acquisition unit 14 in the sixth modification is configured to acquire image information captured by the second imaging unit 2b from the X-ray detection unit 25. Furthermore, in the sixth modification, the rotation angle acquisition unit 15 is configured to acquire the rotation angle of the first imaging unit 2a acquired by the first imaging unit 2a and the rotation angle of the second imaging unit 2b acquired by the second imaging unit 2b.

[0140] In the sixth modified example, the image processing unit 17 is configured to generate an X-ray image captured by the first imaging unit 2a and an X-ray image captured by the second imaging unit 2b based on the image information acquired by the image information acquisition unit 14. In addition, in the sixth modified example, the image processing unit 17 is configured to generate a subject image 42 based on a plurality of X-ray images captured by the first imaging unit 2a. In addition, the image processing unit 17 is configured to generate a subject image 42 based on a plurality of X-ray images captured by the second imaging unit 2b. The structure of the image processing unit 17 generating the subject image 42 is the same as that in the above-described embodiment, and therefore a detailed description thereof will be omitted.

[0141] Next, refer to Figure 24 The following describes a process of generating the subject image 42 by the X-ray imaging apparatus 100 according to the sixth modification.

[0142] In step 201 , the image processing unit 17 acquires a plurality of X-ray images captured by the first imaging unit 2 a and the second imaging unit 2 b .

[0143] Next, in step 202 , the image processing unit 17 sets a plurality of reference planes 34 based on the plurality of X-ray images captured by the first imaging unit 2 a and the plurality of X-ray images captured by the second imaging unit 2 b .

[0144] Next, in step 203 , the image processing unit 17 performs coordinate conversion of each pixel on the plurality of X-ray images captured by the first imaging unit 2 a and the second imaging unit 2 b .

[0145] Next, in step 204, the image processing unit 17 selects pixels corresponding to pixel corresponding points on each reference plane 34 based on the plurality of coordinate-transformed X-ray images captured by the first imaging unit 2a and the second imaging unit 2b, and determines the pixel value of each pixel corresponding point.

[0146] Next, in step 205, the image processing unit 17 determines whether the pixel values ​​of all the corresponding points of the pixels on each reference surface 34 have been determined. If the pixel values ​​of all the corresponding points of the pixels on each reference surface 34 have been determined, the process proceeds to step 206. If the pixel values ​​of all the corresponding points of the pixels on each reference surface 34 have not been determined, the process proceeds to step 204.

[0147] In step 206, the image processing unit 17 generates the subject image 42 in each reference plane 34. Then, the processing ends.

[0148] With the above configuration, a single administration of contrast agent allows for acquisition of subject images 42 captured by the first imaging unit 2a and the second imaging unit 2b from different angles. This reduces the number of contrast agent administrations compared to a configuration in which contrast agent is administered multiple times and imaging is performed with a single imaging unit 2 at varying imaging angles. Furthermore, imaging time can be shortened, thereby reducing radiation exposure.

[0149] (Other Modifications)

[0150] In addition, the above embodiment illustrates a configuration example in which, when there are multiple X-ray images that capture the corresponding pixel point, the image processing unit 17 selects the pixel value of the pixel closest to the center of the X-ray image that most clearly captures the corresponding pixel point. However, the present invention is not limited to this configuration. For example, the image processing unit 17 may also be configured to determine the pixel value of the corresponding pixel point by selecting the pixel value of the pixel that most clearly captures the corresponding pixel point among the pixels corresponding to the corresponding pixel point within the multiple X-ray images. With this configuration, the pixel value of the pixel with the lowest pixel value is selected as the pixel value of the corresponding pixel point, thereby generating a high-contrast subject image 42 of the desired portion of the subject 30. As a result, the desired portion of the subject 30 can be easily grasped in the subject image 42.

[0151] In the above embodiment, the reference plane 34 is shown as an example of a surface along the detection surface 10a of the X-ray detector 10, but the present invention is not limited to this. For example, the reference plane 34 may also be a surface along the top plate 1. However, if the reference plane 34 is a surface along the top plate 1, when imaging is performed with the imaging unit 2 tilted relative to the top plate 1, the reference plane 34 becomes a surface different from the surface intended by the physician or the like. Therefore, the reference plane 34 is preferably a surface along the detection surface 10a of the X-ray detector 10.

[0152] In the above embodiment, the reference plane 34 is shown as a flat surface, but the present invention is not limited thereto. For example, the reference plane 34 may also be a curved surface. However, if the reference plane 34 is a curved surface, the magnification at the center and ends of the subject image 42 will differ, resulting in an unnatural image. Therefore, the reference plane 34 is preferably a flat surface.

[0153] In addition, while the above embodiment illustrates a configuration in which the moving mechanism 4 includes the top plate retaining portion 4a, the present invention is not limited thereto. When the moving mechanism 4 automatically moves the top plate 1, the top plate retaining portion 4a may not be provided. However, when performing imaging, such as tracking blood flow in a blood vessel, or when the top plate 1 is moved while varying its speed, it is desirable to manually move the top plate 1. Therefore, the moving mechanism 4 preferably includes the top plate retaining portion 4a.

[0154] In addition, in the above embodiment, a configuration example in which the moving mechanism 4 includes a C-arm 12 is shown, but the present invention is not limited thereto. For example, the moving mechanism 4 may not include the C-arm 12. In the case where the moving mechanism 4 does not include the C-arm 12, the X-ray source 9 and the X-ray detection unit 10 may be respectively arranged on the ceiling and the ground. However, in the case where the moving mechanism 4 does not include the C-arm 12, when the imaging unit 2 is tilted relative to the top plate 1 for imaging, it is necessary to adjust the angles of the X-ray source 9 and the X-ray detection unit 10 respectively, and changing the angle of the imaging unit 2 becomes complicated. Therefore, it is preferable that the moving mechanism 4 includes the C-arm 12.

[0155] In addition, in the above embodiment, a structural example is shown in which the image processing unit 17 transforms the coordinates in units of pixels when performing coordinate transformation of multiple X-ray images (X-ray image 40a, X-ray image 40b, X-ray image 40c, and X-ray image 40d), but the present invention is not limited to this. For example, the image processing unit 17 can also be configured to perform coordinate transformation in units of images, taking the coordinates of the pixels located at the center positions of the multiple X-ray images as representatives. If configured in this way, the processing speed of the coordinate transformation can be increased compared to a structure that performs coordinate transformation in units of pixels. However, when coordinate transformation is performed at the image end, the accuracy of the coordinate transformation is reduced compared to a structure that performs coordinate transformation in units of pixels. Therefore, the image processing unit 17 is preferably configured to perform coordinate transformation in units of pixels.

[0156] In addition, in the above embodiment, for ease of explanation, an example of the control processing of the control unit 5 is shown using a flowchart of a process-driven type in which processing is performed sequentially according to the processing flow, but the present invention is not limited to this. In the present invention, the control processing of the control unit 5 can also be performed by an event-driven type (event-driven type) processing in which processing is performed in units of events. In this case, the control processing of the control unit 5 can be performed using a complete event-driven type or a combination of event-driven and process-driven methods.

[0157] [Way]

[0158] It should be understood by those skilled in the art that the above-described exemplary embodiments are specific examples of the following aspects.

[0159] (Item 1)

[0160] An X-ray imaging device comprising:

[0161] an imaging unit including an X-ray source for irradiating an object with X-rays and an X-ray detection unit for detecting the X-rays having passed through the object, the imaging unit being configured to capture an image;

[0162] a moving mechanism including a top plate on which the subject is placed, and capable of moving at least one of the top plate and the imaging unit so as to change a relative position between the top plate and the imaging unit; and

[0163] an image processing unit that acquires the plurality of images while changing the relative position using the moving mechanism, and generates a subject image based on the plurality of images;

[0164] In which, the image processing unit is configured to set the imaging area, i.e., the reference plane, when generating the image of the subject based on the multiple images, and determine the pixel values ​​of the multiple pixel corresponding points contained in the reference plane based on the multiple images, thereby generating the image of the subject in the reference plane. The image processing unit is configured to select the pixel corresponding to the pixel corresponding point in the image that captures the pixel corresponding point most clearly among the multiple images, thereby determining the pixel value of the pixel corresponding point.

[0165] (Item 2)

[0166] The X-ray imaging apparatus according to item 1, wherein:

[0167] The image processing unit is configured to: when there are multiple images that capture the pixel corresponding point, select the pixel value of the pixel that is closest to the center of the image and captures the pixel corresponding point most clearly among the pixels corresponding to the pixel corresponding point of the reference plane in the multiple images, thereby determining the pixel value of the pixel corresponding point.

[0168] (Item 3)

[0169] The X-ray imaging apparatus according to item 1, wherein:

[0170] At least one of the plurality of images is an image of a contrast agent injected into the subject.

[0171] The image processing unit is configured to: when there are multiple images that capture the pixel corresponding point, select the pixel value of the pixel that captures the pixel corresponding point most clearly among the pixels corresponding to the pixel corresponding point in the multiple images and has the highest concentration of the contrast agent, thereby determining the pixel value of the pixel corresponding point.

[0172] (Item 4)

[0173] The X-ray imaging apparatus according to item 1, wherein:

[0174] The image processing unit is configured to: when there are multiple images that capture the pixel corresponding point, select the pixel value of the pixel that captures the pixel corresponding point most clearly among the pixels corresponding to the pixel corresponding point in the multiple images and the pixel value with the lowest pixel value among the pixels corresponding to the pixel corresponding point, thereby determining the pixel value of the pixel corresponding point.

[0175] (Item 5)

[0176] The X-ray imaging apparatus according to item 1, wherein:

[0177] The reference plane is a plane along the detection plane of the X-ray detection unit.

[0178] (Item 6)

[0179] The X-ray imaging apparatus according to item 1, wherein:

[0180] The reference surface is a plane.

[0181] (Item 7)

[0182] The X-ray imaging apparatus according to item 1, wherein:

[0183] The reference plane is a plane where the magnification ratios of the plurality of images are uniform.

[0184] (Item 8)

[0185] The X-ray imaging apparatus according to item 1, wherein:

[0186] The moving mechanism further includes a top plate holding portion that holds the top plate so as to be manually movable at least within a plane.

[0187] (Item 9)

[0188] The X-ray imaging apparatus according to item 8, wherein:

[0189] The image processing unit is configured to generate a strip image as an image of the subject along the movement path in the reference plane based on the plurality of images acquired while the subject is manually moved along an arbitrary movement path.

[0190] (Item 10)

[0191] The X-ray imaging apparatus according to item 8, wherein:

[0192] The moving mechanism further includes a C-arm that integrally holds the X-ray source and the X-ray detection unit.

[0193] (Item 11)

[0194] The X-ray imaging apparatus according to item 10, wherein:

[0195] The image processing unit is configured to generate one image of the subject based on the plurality of images captured by rotating the C-arm while moving the top using the moving mechanism.

[0196] (Item 12)

[0197] The X-ray imaging apparatus according to item 10, wherein:

[0198] The image processing unit is configured to generate a plurality of subject images at various angles based on images at the same rotation angle of the C-arm among the plurality of images captured by rotating the C-arm while moving the top using the moving mechanism.

[0199] Description of Reference Numerals

[0200] 1: top plate; 2, 2a, 2b: photographing unit; 4: moving mechanism; 4a: top plate holding unit; 9, 24: X-ray source; 10, 25: X-ray detection unit; 10a: detection surface; 12: C-arm; 17: image processing unit; 30: subject; 34: reference plane; 35a, 35b, 35c, 35d, 35e: pixel corresponding points; 40a, 40b, 40c, 40d, 400a, 400b, 400c, 400d, 400e, 400f, 400g, 400h: X-ray image; 41a, 41b, 41c, 41d, 41e: pixels corresponding to pixel corresponding points; 42: subject image; 100: X-ray photographing device; 420: strip image.

Claims

1. An X-ray imaging device comprising: an imaging unit including an X-ray source for irradiating an object with X-rays and an X-ray detection unit for detecting the X-rays having passed through the object, the imaging unit being configured to capture an image; a moving mechanism including a top plate on which the subject is placed, and capable of moving at least one of the top plate and the imaging unit so as to change a relative position between the top plate and the imaging unit; as well as an image processing unit that acquires the plurality of images while changing the relative position using the moving mechanism, and generates a subject image based on the plurality of images; In which, the image processing unit is configured to set the imaging area when generating the object image based on multiple images, that is, a reference plane different from the detection plane of the X-ray detection unit, and determine the pixel values ​​of each of the multiple pixel corresponding points contained in the reference plane based on the multiple images after the coordinate transformation onto the reference plane, thereby generating the object image in the reference plane. The image processing unit is configured to select the pixel corresponding to the pixel corresponding point in the image that captures the pixel corresponding point most clearly among the multiple images, thereby determining the pixel value of the pixel corresponding point.

2. The X-ray imaging device according to claim 1, wherein The image processing unit is configured to: when there are multiple images that capture the pixel corresponding point, select the pixel value of the pixel that is closest to the center of the image and captures the pixel corresponding point most clearly among the pixels corresponding to the pixel corresponding point of the reference plane in the multiple images, thereby determining the pixel value of the pixel corresponding point.

3. The X-ray imaging device according to claim 1, wherein At least one of the plurality of images is an image of a contrast agent injected into the subject. The image processing unit is configured to: when there are multiple images that capture the pixel corresponding point, select the pixel value of the pixel that captures the pixel corresponding point most clearly among the pixels corresponding to the pixel corresponding point in the multiple images and has the highest concentration of the contrast agent, thereby determining the pixel value of the pixel corresponding point.

4. The X-ray imaging device according to claim 1, wherein The image processing unit is configured to: when there are multiple images that capture the pixel corresponding point, select the pixel value of the pixel that captures the pixel corresponding point most clearly among the pixels corresponding to the pixel corresponding point in the multiple images and the pixel value with the lowest pixel value among the pixels corresponding to the pixel corresponding point, thereby determining the pixel value of the pixel corresponding point.

5. The X-ray imaging device according to claim 1, wherein The reference plane is a plane along the detection plane of the X-ray detection unit.

6. The X-ray imaging device according to claim 1, wherein The reference surface is a plane.

7. The X-ray imaging device according to claim 1, wherein The reference plane is a plane where the magnification ratios of the plurality of images are uniform.

8. The X-ray imaging device according to claim 1, wherein The moving mechanism further includes a top plate holding portion that holds the top plate so as to be manually movable at least within a plane.

9. The X-ray imaging device according to claim 8, wherein The image processing unit is configured to generate a strip image as an image of the subject along the movement path in the reference plane based on the plurality of images acquired while the subject is manually moved along an arbitrary movement path.

10. The X-ray imaging device according to claim 8, wherein The moving mechanism further includes a C-arm that integrally holds the X-ray source and the X-ray detection unit.

11. The X-ray imaging device according to claim 10, wherein: The image processing unit is configured to generate one image of the subject based on the plurality of images captured by rotating the C-arm while moving the top using the moving mechanism.

12. The X-ray imaging device according to claim 10, wherein: The image processing unit is configured to generate a plurality of subject images at various angles based on images at the same rotation angle of the C-arm among the plurality of images captured by rotating the C-arm while moving the top using the moving mechanism.

Images