X-ray imaging device

Abstract

This X-ray imaging device (100) is provided with: an optical imaging unit (31) for imaging an optical image (70); and an optical imaging control unit (32). The optical imaging control unit is configured to perform control for switching from a first mode to a second mode. The first mode is for displaying, with reference to a prescribed fixed position in a real space: an optical image on which is superimposed a region display (80) which includes at least one of a detection unit region display (81), an X-ray irradiation field region display (84), and an X-ray lighting field region display (87); or an optical image on which a region display is not superimposed. The second mode is for displaying an optical image on which is superimposed a region display that references a position on a body surface (101a) of a subject (101) in a real space.

Description

X-ray equipment

[0001] The present invention relates to an X-ray imaging apparatus, and more particularly to an X-ray imaging apparatus equipped with an optical imaging unit.

[0002] 2. Description of the Related Art Conventionally, X-ray imaging devices including an optical imaging unit have been known. Such an X-ray imaging device is disclosed, for example, in U.S. Patent Application Publication No. 2021 / 0150704.

[0003] The above-mentioned U.S. Patent Application Publication No. 2021 / 0150704 describes an imaging system (X-ray imaging device). This imaging system includes an X-ray source, an X-ray detector, a camera, and a display unit. The camera is positioned facing the patient. In addition, in the imaging system disclosed in the above-mentioned U.S. Patent Application Publication No. 2021 / 0150704, when adjusting the positions of the patient and the X-ray source, a video image of the patient captured by the camera is displayed on the display unit. In addition, in the imaging system disclosed in the above-mentioned U.S. Patent Application Publication No. 2021 / 0150704, a frame corresponding to the area where X-rays irradiated from the X-ray source are detected by the X-ray detector is superimposed on the video image of the patient and displayed on the display unit. In this case, the frame corresponding to the area detected by the X-ray detector is deformed into a shape corresponding to the patient's body surface and displayed on the patient's body surface.

[0004] US Patent Application Publication No. 2021 / 0150704

[0005] However, as in the imaging system (X-ray imaging device) of the above-mentioned U.S. Patent Application Publication No. 2021 / 0150704, when a frame (region display) corresponding to the region detected by the X-ray detector is displayed in a shape that corresponds to the body surface of the patient (subject), the position and shape of the region display change each time the position of the subject's body surface changes. When adjusting the position of the subject and the X-ray source (X-ray irradiator), a rough position adjustment between the subject and the X-ray irradiator is performed, followed by a fine adjustment between the subject and the X-ray irradiator. When the rough position adjustment between the subject and the X-ray irradiator is performed, the position of the subject fluctuates significantly. When the position of the subject fluctuates significantly, the position and shape of the region display change frequently, making it difficult to confirm the position of the subject in the video image (optical image) displayed on the display unit. As a result, the efficiency of the position adjustment process decreases. Therefore, there is a demand for an X-ray imaging device that can easily perform position adjustment while suppressing a decrease in the efficiency of the position adjustment process.

[0006] 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 device that allows easy position adjustment while suppressing a decrease in the efficiency of position adjustment work.

[0007] An X-ray imaging apparatus according to a first aspect of the present invention includes an X-ray irradiation unit including an X-ray tube, an X-ray detection unit that detects X-rays irradiated from the X-ray irradiation unit and transmitted through a subject, an optical imaging unit that captures an optical image of the subject, a display unit that displays the optical image captured by the optical imaging unit, a control unit that controls the display of the optical image on the display unit, and an input receiving unit that receives input from an operator, and when performing position adjustment, the control unit determines an area in the optical image where the X-ray detection unit is located, based on the input from the operator received by the input receiving unit, using a predetermined fixed position in real space as a reference. The optical image display device is configured to control switching from a first mode in which an optical image is displayed on which a region display including at least one of a detection unit region display showing an area in the optical image to be irradiated with X-rays by the X-ray irradiator, an X-ray irradiation field region display showing an area in the optical image to be irradiated with X-rays by the X-ray irradiator, and an X-ray collection field region display showing an area in the optical image to collect the X-rays irradiated by the X-ray irradiator is displayed, to a second mode in which an optical image is displayed on which a region display based on a position on the body surface of the subject in real space is superimposed. Note that the predetermined fixed position in real space is a position that is preset in the direction of the X-ray irradiation axis when the X-ray irradiator and the X-ray detection unit are facing each other.

[0008] An X-ray imaging apparatus according to a second aspect of the present invention includes an X-ray irradiator including an X-ray tube, an X-ray detector that detects X-rays irradiated from the X-ray irradiator and transmitted through a subject, an optical imaging unit that captures an optical image of the subject, a display unit that displays the optical image captured by the optical imaging unit, a body surface position acquisition unit that acquires the position of the body surface of the subject in real space, a controller that controls the display of the optical image, and an input receiving unit that receives input from an operator, and when adjusting the position, the controller determines a predetermined fixed position in real space based on the input from the operator received by the input receiving unit or the position of the body surface of the subject acquired by the body surface position acquisition unit. As a reference, the optical image is configured to display an optical image on which an area display including at least one of a detection unit area display showing the area in the optical image where the X-ray detection unit is located, an X-ray irradiation field area display showing the area in the optical image where X-rays are irradiated by the X-ray irradiation unit, and an X-ray irradiation field area display showing the area in the optical image where the X-rays irradiated by the X-ray irradiation unit are collected, or to perform control to switch from a first mode in which an optical image is displayed without an area display being superimposed on the optical image, to a second mode in which an optical image is displayed on which an area display based on the position on the body surface of the subject in real space is superimposed.

[0009] As described above, the X-ray imaging apparatus in the first and second aspects includes a control unit that, when adjusting the position, switches from a first mode in which an optical image is displayed with a region display superimposed based on a predetermined fixed position in real space, or an optical image in which no region display is displayed, without superimposing the region display on the optical image, to a second mode in which an optical image is displayed with a region display superimposed based on a position on the body surface of the subject in real space, based on an input from an operator.

[0010] As a result, when an optical image with a superimposed region display is displayed in the first mode, the optical image with the superimposed region display is displayed at a fixed position. Therefore, even if the position of the subject's body surface changes when roughly adjusting the position of the subject and the X-ray irradiator, the region display can be fixed and displayed. Therefore, it is possible to prevent the position and shape of the region display from changing, which can prevent a decrease in the efficiency of the position adjustment process when roughly adjusting the position of the subject and the X-ray irradiator, caused by the position and shape of the region display frequently changing. Furthermore, when an optical image without a superimposed region display is displayed in the first mode, the region display is not superimposed on the optical image. Therefore, it is possible to prevent a decrease in the efficiency of the position adjustment process when roughly adjusting the position of the subject and the X-ray irradiator, caused by the position and shape of the region display frequently changing. Furthermore, after roughly adjusting the position of the subject and the X-ray irradiator, the operator fine-tunes the position of the subject and the X-ray irradiator. In fine-tuning the position between the subject and the X-ray irradiator, the positions of the subject and the X-ray irradiator are adjusted so that the region of X-rays irradiated onto the subject's body surface corresponds to the detection region of the X-ray detection unit. In the second mode, which is switched from the first mode based on operator input, an optical image with a region display superimposed on the subject's body surface is displayed. Therefore, when fine-tuning the position between the subject and the X-ray irradiator, the operator can easily adjust the position while visually recognizing the region display superimposed on the subject's body surface in the optical image. As a result, an X-ray imaging device can be provided that allows for easy position adjustment while suppressing a decrease in work efficiency.

[0011] Furthermore, in a second aspect, the X-ray imaging apparatus includes a body surface position acquisition unit that acquires the position of the body surface of the subject in real space and a control unit that controls display of the optical image on the display unit, and the control unit, when performing position adjustment, controls switching from a first mode in which an optical image on which a region display based on a predetermined fixed position in real space is superimposed, or an optical image without a region display superimposed on the optical image, to a second mode in which an optical image on which a region display based on the position of the body surface of the subject in real space is superimposed, based on the position of the body surface of the subject acquired by the body surface position acquisition unit. This allows switching from the first mode to the second mode based on the position of the body surface of the subject acquired by the body surface position acquisition unit, so that automatic switching from the first mode to the second mode is possible without an operator's input. As a result, an X-ray imaging apparatus can be provided that allows easy position adjustment while simultaneously reducing the operator's workload and preventing a decrease in work efficiency.

[0012] 1 is a schematic diagram showing the overall configuration of an X-ray imaging apparatus according to a first embodiment; FIG. 2 is a schematic diagram showing the configuration of a holding unit according to the first embodiment; FIG. 3 is a block diagram showing the overall configuration of an X-ray imaging apparatus according to the first embodiment; FIG. 4 is a schematic diagram showing the configuration of an optical image generated by an optical imaging control unit; FIG. 5 is a schematic diagram for explaining an optical image in which area displays including a detection unit area display, an X-ray irradiation field area display, and an AEC area display are superimposed on an optical image; FIG. 6 is a schematic diagram for explaining an optical image displayed in a first mode; FIG. 7 is a schematic diagram for explaining an optical image displayed in a second mode; FIG. 8 is a schematic diagram (1) for explaining calculation of an X-ray tube-to-subject distance by an optical imaging control unit of an X-ray imaging apparatus according to the first embodiment; FIG. 9 is a schematic diagram (2) for explaining calculation of an X-ray tube-to-subject distance by an optical imaging control unit of an X-ray imaging apparatus according to the first embodiment; and FIG. 10 is a flowchart for explaining control processing of an image display method by an X-ray imaging apparatus. A block diagram showing the overall configuration of an X-ray imaging apparatus according to a second embodiment. A schematic diagram for explaining a configuration in which an optical imaging control unit according to the second embodiment switches a mode in which an area display is displayed from a second mode to a first mode. 10 is a flowchart for explaining a configuration in which an optical imaging control unit according to a second embodiment switches a mode in which a region display is to be displayed from a second mode to a first mode. FIG. 11 is a block diagram showing the overall configuration of an X-ray imaging apparatus according to a third embodiment. FIG. 12 is a flowchart for explaining control processing of an image display method by the X-ray imaging apparatus of the third embodiment. FIG. 13 is a schematic diagram (1) for explaining calculation of an X-ray tube-to-subject distance by an optical imaging control unit of an X-ray imaging apparatus according to a modified example. FIG. 14 is a schematic diagram (2) for explaining calculation of an X-ray tube-to-subject distance by an optical imaging control unit of an X-ray imaging apparatus according to a modified example.

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings.

[0014] First Embodiment (Configuration of X-Ray Imaging Apparatus) The configuration of an X-ray imaging apparatus 100 according to a first embodiment of the present invention will be described with reference to FIGS.

[0015] FIG. 1 shows an example of a ceiling-suspended X-ray imaging device 100. The X-ray imaging device 100 includes an X-ray irradiator 10, an X-ray detector 20, an optical imaging unit 31, a holder 40, a moving mechanism 50, an apparatus controller 60, and an input unit 61. The X-ray imaging device 100 is an imaging device including a medical X-ray imaging device, and is configured to perform X-ray imaging of a subject 101 to be imaged. In the X-ray imaging device 100, X-rays irradiated from the X-ray irradiator 10 are detected by the X-ray detector 20, thereby performing X-ray imaging of the subject 101. In the X-ray imaging device 100, an optical image 70 (see FIG. 4 ) capturing the appearance of the subject 101 is also captured by the optical imaging unit 31. In addition, in the X-ray imaging device 100, the X-ray irradiation unit 10, the X-ray detection unit 20, the optical imaging unit 31, the holding unit 40, and the moving mechanism 50 are installed in the imaging room 110, and the device control unit 60 and the input unit 61 are installed outside the imaging room 110.

[0016] In the ceiling-suspended X-ray imaging device 100, a holding unit 40 that holds the X-ray irradiation unit 10 is suspended from the ceiling by a moving mechanism 50 that is arranged on the ceiling of an imaging room 110. The holding unit 40 is held movably within the imaging room 110 by the moving mechanism 50. The vertical (perpendicular) direction is defined as the Z direction, and two mutually orthogonal horizontal directions are defined as the X direction and the Y direction.

[0017] The X-ray imaging apparatus 100 includes an imaging table 21 for imaging a subject 101 in a lying position (supine position), and an imaging stand 22 for imaging a subject 101 in an upright position (standing position). An X-ray detection unit 20 is movably supported on each of the imaging table 21 and the imaging stand 22. The X-ray detection unit 20 includes, for example, a flat panel detector (FPD). The X-ray detection unit 20 is configured to detect X-rays irradiated from the X-ray irradiation unit 10 and transmitted through the subject 101. The moving mechanism 50 is capable of moving the holding unit 40 at least between an imaging position in a supine position using the imaging table 21 (see solid line in FIG. 1 ) and an imaging position in an upright position using the imaging stand 22 (see two-dot chain line in FIG. 1 ).

[0018] The X-ray detection unit 20 is also provided with an AEC (Auto Exposure Control) 23. The AEC 23 is configured to collect X-rays irradiated by the X-ray irradiation unit 10. The AEC 23 is a device provided in the X-ray detection unit 20, collects (detects) X-rays that have passed through the subject 101, and controls the tube voltage, tube current, irradiation time, etc. of the X-ray tube 11 (see FIG. 2 ) provided in the X-ray irradiation unit 10 according to the amount of collected X-rays.

[0019] In X-ray imaging in a lying position, the holding unit 40 is arranged at a position vertically facing the X-ray detection unit 20 of the imaging table 21, and X-ray imaging of the subject 101 lying on the imaging table 21 is performed between the X-ray irradiation unit 10 and the X-ray detection unit 20 that are vertically facing each other, and an image (optical imaging) of the subject 101 lying on the imaging table 21 is taken by the optical imaging unit 31. In X-ray imaging in a standing position, the holding unit 40 is arranged at a position horizontally facing the X-ray detection unit 20 of the imaging stand 22, and X-ray imaging of the subject 101 standing in front of the imaging stand 22 is performed between the X-ray irradiation unit 10 and the X-ray detection unit 20 that are horizontally facing each other, and an image of the subject 101 standing in front of the imaging stand 22 is taken by the optical imaging unit 31.

[0020] The moving mechanism 50 is configured to hold the holding unit 40 so that it can move in the horizontal direction (X direction and Y direction) and the vertical direction (Z direction). The moving mechanism 50 includes a ceiling suspension unit 51 and a support unit 52. The moving mechanism 50 is supported by rails 53 provided on the ceiling of the radiography room 110. The ceiling suspension unit 51 is configured to be movable in the horizontal direction by the rails 53. The ceiling suspension unit 51 is configured to support the support unit 52. The support unit 52 is configured to support the holding unit 40. The support unit 52 is configured to be extendable and retractable in the vertical direction. The holding unit 40 is configured to be movable in the vertical direction by the support unit 52. The moving mechanism 50 also moves the X-ray detection units 20 arranged on the radiography table 21 and the radiography stand 22.

[0021] As shown in FIG. 2 , the X-ray irradiation unit 10 includes an X-ray tube 11 and a collimator unit 12. The X-ray irradiation unit 10 is configured to irradiate a subject 101 (see FIG. 1 ) with X-rays from the X-ray tube 11. The X-ray tube 11 is configured to irradiate X-rays by applying a predetermined voltage. The collimator unit 12 has a plurality of shielding plates (collimator leaves) whose positions can be adjusted. The collimator unit 12 is configured to adjust the irradiation field of the X-rays irradiated from the X-ray tube 11 by shielding a portion of the X-rays from the X-ray tube 11. The collimator unit 12 is provided near the X-ray tube 11 in the X-ray irradiation direction of the X-ray tube 11.

[0022] The holding unit 40 includes a display operation unit 41 and a grip unit 42. The holding unit 40 is configured to be movable in the horizontal and vertical directions via a movement mechanism 50 (see FIG. 1) either manually or under the control of a device control unit 60 (see FIG. 1). In the first embodiment, the optical imaging unit 31 is provided in the holding unit 40 together with the X-ray irradiation unit 10. Specifically, the holding unit 40 is provided with an imaging unit 30 configured with the optical imaging unit 31 and an optical imaging control unit 32. In the first embodiment, the light source unit 33 and the input receiving unit 43 are also provided in the holding unit 40. The optical imaging control unit 32 and the display operation unit 41 are examples of a "control unit" and a "display unit," respectively.

[0023] The display operation unit 41 includes, for example, a touch panel type liquid crystal display. The display operation unit 41 is configured to function as an image display unit that displays the optical image 70 (see FIG. 4 ) captured by the optical imaging unit 31, and also as an operation unit into which various operations are input by an operator (such as a doctor or technician). The display operation unit 41 outputs a signal indicating the received input operation to the optical imaging control unit 32 and the device control unit 60.

[0024] The grip portion 42 is provided for an operator to grasp when manually moving the holding portion 40. The grip portion 42 transmits the operating force of the operator to the holding portion 40.

[0025] The optical imaging unit 31 is provided on an outer surface of the collimator unit 12. In the first embodiment, the optical imaging unit 31 is provided on the outer surface of the collimator unit 12 on the longitudinal side of the imaging table 21 when the patient is in a lying position. Furthermore, the optical imaging unit 31 is provided on the outer surface of the collimator unit 12 on the lateral side that intersects with the detection surface of the X-ray detection unit 20 when the patient is in an upright position. The optical imaging unit 31 faces the irradiation direction of X-rays from the X-ray irradiator 10. When the X-ray irradiator 10 faces the subject 101 and the X-ray detection unit 20, the optical imaging unit 31 can capture an optical image 70 of the subject 101 and the X-ray detection unit 20 from the X-ray irradiator 10 side. The imaging range of the optical imaging unit 31 is set to include the range of the irradiation field irradiated with X-rays and to be larger than the range of the X-ray irradiation field.

[0026] In the first embodiment, as shown in FIG. 2 , the collimator unit 12 is provided with a light source unit 33 and an input receiving unit 43. The light source unit 33 is provided inside the collimator unit 12. The light source unit 33 is configured to irradiate visible light onto an irradiation field region 33a (see FIG. 4 ) indicating an area to be irradiated with X-rays by the X-ray irradiation unit 10. Specifically, like the X-rays irradiated from the X-ray irradiation unit 10, a portion of the visible light irradiated from the light source unit 33 is blocked by a plurality of shielding plates (collimator leaves) of the collimator unit 12, thereby adjusting the irradiation field. Therefore, the irradiation field of the visible light irradiated from the light source unit 33 becomes equal to the irradiation field of the X-rays irradiated from the X-ray irradiation unit 10 by being adjusted by the plurality of shielding plates (collimator leaves) of the collimator unit 12. The light source unit 33 includes a light-emitting element such as an LED (Light Emitting Diode), for example.

[0027] In the first embodiment, the input accepting unit 43 is configured to accept input from an operator. The input accepting unit 43 is, for example, a push button that operates the light source unit 33. That is, the input accepting unit 43 is configured to accept an operation input to turn on the light source unit 33. When the input accepting unit 43 is operated (pressed) by the operator, visible light is irradiated from the light source unit 33.

[0028] As shown in FIG. 3 , the optical imaging unit 31 includes an imaging element 31a. The optical imaging unit 31 is, for example, an optical camera. The imaging element 31a includes, for example, a charge-coupled device (CCD) image sensor or a complementary metal oxide semiconductor (CMOS) image sensor. The optical imaging control unit 32 is, for example, a microcomputer including a central processing unit (CPU), memory, etc. The optical imaging control unit 32 transmits and receives signals to and from the device control unit 60 via a wireless or wired connection.

[0029] As shown in FIG. 4 , the optical imaging unit 31 (see FIG. 3 ) is configured to capture an optical image 70 of the subject 101. The optical imaging control unit 32 (see FIG. 3 ) is configured to receive a signal output from the imaging element 31 a (see FIG. 3 ) and generate the optical image 70 based on the received signal. The optical imaging control unit 32 is also configured to control the display operation unit 41 (see FIG. 3 ) to output and display the generated optical image 70. Note that the example shown in FIG. 4 is an optical image 70 in a state in which visible light emitted from the light source unit 33 (see FIG. 3 ) is irradiated onto the irradiation field region 33 a. Therefore, the optical image 70 shown in FIG. 4 includes the subject 101, the X-ray detection unit 20, and the irradiation field region 33 a. Note that if visible light is not irradiated from the light source unit 33, the irradiation field region 33 a is not captured in the optical image 70.

[0030] In the first embodiment, the optical imaging control unit 32 is configured to perform control to switch the display mode when displaying the optical image 70 from the first mode to the second mode. Details of the first mode and the second mode, and details of the configuration in which the optical imaging control unit 32 switches between the first mode and the second mode will be described later.

[0031] As shown in FIG. 3 , the device control unit 60 includes a memory 60a. The device control unit 60 controls X-ray imaging by the X-ray irradiation unit 10 and the X-ray detection unit 20, and controls the movement of the holding unit 40. Specifically, the device control unit 60 includes a CPU. The input unit 61 has a function of accepting input operations related to X-ray imaging. The input operations include setting imaging conditions for X-ray imaging and issuing an instruction to start X-ray irradiation. The device control unit 60 controls X-ray imaging based on parameters and various programs that are set in advance and stored in the memory 60a. The device control unit 60 controls the amount of adjustment of the irradiation field by the collimator unit 12 (see FIG. 2 ).

[0032] In the first embodiment, the memory 60 a stores body type information 102 of the subject 101 , position information 103 of the X-ray detection unit 20 , and standard body thickness information 104 .

[0033] The body type information 102 of the subject 101 includes, for example, the height and weight of the subject 101. The body type information 102 of the subject 101 is obtained, for example, from an order for photographing the subject 101, and is stored in the memory 60a.

[0034] Furthermore, the position information 103 of the X-ray detection unit 20 includes, for example, the amount of movement of the X-ray detection unit 20 from the initial position or the position coordinates of the X-ray detection unit 20 after movement. Every time the X-ray detection unit 20 is moved, the position information 103 of the X-ray detection unit 20 is stored in the memory 60a.

[0035] The standard body thickness information 104 is body thickness information set in advance for each imaging region of the subject 101. Specifically, the standard body thickness information 104 is a statistical value (average value) of the body thickness for each imaging region of a subject with a standard physique. The standard body thickness information 104 is publicly available, and is obtained in advance and stored in the memory 60a.

[0036] In the X-ray imaging apparatus 100, the movement mechanism 50 includes a drive unit 50a such as a motor and a motion detector 50b that detects the operation of the drive unit 50a. The motion detector 50b includes, for example, a potentiometer that detects the rotation of the motor. The drive unit 50a and the motion detector 50b are disposed in various parts of the movement mechanism 50 that move the holder 40, and are also disposed on the imaging table 21 (see FIG. 1) and the imaging stand 22 (see FIG. 1) to change the position of the X-ray detection unit 20. The device controller 60 controls the operation of the movement mechanism 50 based on input operations on the input unit 61 or the display / operation unit 41, or on the operating force applied to the grip 42 of the holder 40, thereby changing the position and angle of the X-ray irradiation unit 10 and the position of the X-ray detection unit 20. The device controller 60 also outputs a control signal that controls the operation of the drive unit 50a and controls the operation of the movement mechanism 50 through feedback control based on a detection signal indicating the operation of the drive unit 50a detected by the motion detector 50b.

[0037] In the first embodiment, the device control unit 60 outputs the position and angle of the X-ray irradiator 10 held by the holder 40 and the positions of the X-ray detectors 20 arranged on the radiography table 21 and the radiography stand 22 to the optical imaging control unit 32. The optical imaging control unit 32 acquires the arrangement of the X-ray irradiator 10 and the arrangement of the X-ray detectors 20 based on input from the device control unit 60. The optical imaging control unit 32 also acquires the amount of adjustment of the irradiation field by the collimator unit 12 based on input from the device control unit 60. In the first embodiment, the device control unit 60 also stores position information 103 of the X-ray detectors 20 in the memory 60a.

[0038] (Display Control by Optical Imaging Control Unit) As shown in FIG. 5 , in the first embodiment, the optical imaging control unit 32 (see FIG. 3 ) is configured to superimpose a region display 80 on the optical image 70 and display it on the display operation unit 41 (see FIG. 3 ). Note that the following description will focus on the control of the display on the display operation unit 41 by the optical imaging control unit 32 when X-ray imaging is performed with the subject 101 in an upright position (standing position). The above control is also similar when X-ray imaging is performed with the subject 101 lying on the imaging table 21 (see FIG. 1 ) (supine position), and therefore a description thereof will be omitted. Also, FIGS. 5 to 7 show an example of performing X-ray imaging of the chest of the subject 101.

[0039] The region display 80 includes at least one of a detection unit region display 81 indicating the region in the optical image 70 where the X-ray detection unit 20 is located, an X-ray irradiation field region display 84 indicating the region in the optical image 70 where X-rays are irradiated by the X-ray irradiation unit 10 (irradiation field region 33a (see FIG. 4)), and an AEC region display 87 indicating the region in the optical image 70 where the X-rays irradiated by the X-ray irradiation unit 10 are collected. In the example shown in FIG. 5 , the region display 80 includes all of the detection unit region display 81, the X-ray irradiation field region display 84, and the AEC region display 87. The AEC region display 87 is an example of an "X-ray irradiation field region display" in the claims.

[0040] The detection unit region display 81 indicates the region in the optical image 70 where the X-ray detection unit 20 is located. The optical imaging control unit 32 acquires the three-dimensional layout of the X-ray irradiator 10 (see FIG. 3 ) and the X-ray detection unit 20, as well as the three-dimensional layout of the optical imaging unit 31 (see FIG. 3 ). Because the optical imaging unit 31 is disposed in the holder 40 (see FIG. 3 ) together with the X-ray irradiator 10, the optical imaging control unit 32 calculates the three-dimensional position of the optical imaging unit 31 using pre-stored parameters based on the acquired position of the X-ray irradiator 10. The optical imaging control unit 32 then detects the region in the optical image 70 where the X-ray detection unit 20 is located by performing geometric calculations based on the acquired three-dimensional positional relationship between the X-ray irradiator 10, the X-ray detection unit 20, and the optical imaging unit 31. The optical imaging control unit 32 may also acquire the position of the optical imaging unit 31 calculated by the device control unit 60.

[0041] The optical imaging control unit 32 generates a detector region display 81 of the region display 80 based on the region where the detected X-ray detection unit 20 is located. The detector region display 81 shows the region where the X-ray detection unit 20 is located in a rectangular shape. The detector region display 81 shows, for example, a square region. The detector region display 81 has a center display 82 indicating the center of the region where the X-ray detection unit 20 is located and four L-shaped region displays 83 indicating the four corners of the rectangular region. The center display 82 has a cross shape and is located at the position where the diagonal lines of the rectangular region intersect. For convenience, the center display 82 and the four region displays 83 are illustrated in white, but may be displayed in blue, for example. The detector region display 81 also provides a guide to the position and range of the region in the optical image 70 where X-rays can be detected by the X-ray detection unit 20. Note that the region shown by the detector region display 81 may be smaller or larger than the actual region where X-rays can be detected by the X-ray detection unit 20.

[0042] 5 , the optical imaging control unit 32 is configured to control the display operation unit 41 to display an X-ray irradiation field area display 84 and an AEC area display 87 as an area display 80 superimposed on the optical image 70. As with the detection unit area display 81, the optical imaging control unit 32 detects an irradiation field area 33a in the optical image 70 where X-rays are irradiated by the X-ray irradiation unit 10 by performing geometric calculations based on the acquired three-dimensional positional relationship between the X-ray irradiation unit 10, the X-ray detection unit 20, and the optical imaging unit 31. Then, the optical imaging control unit 32 generates an X-ray irradiation field area display 84 based on the detected irradiation field area 33a where X-rays are irradiated.

[0043] Like the detection unit area display 81, the X-ray irradiation field area display 84 shows the area irradiated with X-rays in a rectangular shape. The X-ray irradiation field area display 84 shows, for example, a square area. The X-ray irradiation field area display 84 has an area display 85, which is a rectangular frame line showing the irradiation field area 33a irradiated with X-rays, and a dotted line display 86, which is a pair of straight dotted lines that intersect at right angles to each other and indicate the center of the irradiation field area 33a irradiated with X-rays. The pair of dotted line displays 86 are arranged perpendicular to each other and pass through the center position where the diagonal lines of the rectangle of the area display 85 intersect. The pair of dotted line displays 86 are also arranged to extend outside the rectangular frame line of the area display 85. For convenience, the area display 85 and the pair of dotted line displays 86 are illustrated in white, but are actually displayed in a color (e.g., yellow) different from that of the detection unit area display 81. Furthermore, the X-ray irradiation field region display 84 indicates a guide to the position and range of the region irradiated with X-rays in the optical image 70. Note that the region indicated by the X-ray irradiation field region display 84 may be smaller or larger than the region actually irradiated with X-rays.

[0044] In the first embodiment, the optical imaging control unit 32 is configured to change the size of an X-ray irradiation field region display 84 superimposed on the optical image 70 on the display operation unit 41 in accordance with the X-ray irradiation field defined by adjustment of the collimator unit 12. The optical imaging control unit 32 changes the size of a region display 85, which is a rectangular frame line, in the X-ray irradiation field region display 84 superimposed on the optical image 70, based on the value of the adjustment amount of the collimator unit 12 acquired from the device control unit 60. Note that even when the size of the region display 85 indicated by the rectangular frame line in the X-ray irradiation field region display 84 is changed, the size of the dotted line display 86 is not changed.

[0045] The AEC region display 87 shows the position and shape of the AEC 23 (see FIG. 1 ) provided in the X-ray detection unit 20. The position and shape of the AEC 23 provided in the X-ray detection unit 20 are known. Furthermore, as described above, when generating the detection unit region display 81, the optical imaging control unit 32 detects the region in the optical image 70 where the X-ray detection unit 20 is located. Therefore, the optical imaging control unit 32 generates the AEC region display 87 based on the detected location of the X-ray detection unit 20 and the position and shape of the AEC 23 in the X-ray detection unit 20. The AEC is provided in the X-ray detection unit 20. Therefore, although the AEC region display 87 is illustrated in white for convenience, it is displayed in the same color (e.g., blue) as the detection unit region display 81. In the example shown in FIG. 5 , two AEC region displays 87 are superimposed on the optical image 70.

[0046] (Display of Optical Image in First Mode) Next, with reference to FIG. 6, a configuration in which the optical imaging control unit 32 (see FIG. 3) displays the optical image 70 in the first mode will be described.

[0047] In the first embodiment, in the first mode, the optical imaging control unit 32 displays the optical image 70 in which the region in which the X-ray detection unit 20 is located is indicated and in which a region display 80 is superimposed based on a predetermined fixed position in real space, or displays the optical image 70 in which the region display 80 is not displayed by not superimposing the region display 80 on the optical image 70. Fig. 6 illustrates an example in which the optical imaging control unit 32 displays the optical image 70 in which the region display 80 including the detection unit region display 81, the X-ray irradiation field region display 84, and the AEC region display 87 is superimposed based on a fixed position. The first mode is a mode in which, when adjusting the position of the subject 101, the optical image 70 in which the region display 80 based on a fixed position is superimposed is displayed on the display operation unit 41.

[0048] In the first embodiment, when the optical imaging control unit 32 displays the area display 80 superimposed on the optical image 70 in the first mode, the optical imaging control unit 32 is configured to control the display operation unit 41 to superimpose the area display 80 including the detection unit area display 81, the X-ray irradiation field area display 84, and the AEC area display 87 based on a fixed position, on the optical image 70 based on the position information 103 (see Figure 3) of the X-ray detection unit 20 or the standard body thickness information 104 (see Figure 3).

[0049] When the optical imaging control unit 32 superimposes the area display 80 including the detection unit area display 81, the X-ray irradiation field area display 84, and the AEC area display 87 onto the optical image 70 based on a fixed position based on the position information 103 of the X-ray detection unit 20, the detection unit area display 81, the X-ray irradiation field area display 84, and the AEC area display 87 are superimposed on the surface of the X-ray detection unit 20 facing the X-ray irradiation unit 10 (see Figure 3) (the surface of the X-ray detection unit 20). Furthermore, when the optical imaging control unit 32 superimposes the region display 80 including the detection unit region display 81, the X-ray irradiation field region display 84, and the AEC region display 87 on the optical image 70 based on a fixed position based on the standard body thickness information 104, the detection unit region display 81, the X-ray irradiation field region display 84, and the AEC region display 87 are superimposed at a position on the X-ray irradiation unit 10 side from the surface of the X-ray detection unit 20 by the body thickness acquired based on the standard body thickness information 104. Fig. 6 shows an example in which the optical imaging control unit 32 displays the optical image 70 on which the region display 80 including the detection unit region display 81, the X-ray irradiation field region display 84, and the AEC region display 87 are superimposed based on a fixed position based on the position information 103 of the X-ray detection unit 20.

[0050] 6, in the first embodiment, the optical imaging control unit 32 causes the display operation unit 41 to display an SID display area 90 that displays the SID (Source to Image Receptor Distance), which is the distance between the X-ray irradiator 10 and the X-ray detector 20 (X-ray tube-to-detector distance D4 (see FIG. 8)). The optical imaging control unit 32 also causes the display operation unit 41 to display an SOD display area 91 that displays the SOD (Source to Object Distance), which is the distance between the X-ray irradiator 10 and the body surface 101a of the subject 101 (see FIG. 1) (X-ray tube-to-subject distance D1 (see FIG. 8)). In the example shown in FIG. 6, the SOD has not been acquired, and therefore the SOD value is not displayed in the SOD display area 91. In this specification, the body surface 101a of the subject 101 refers to the surface of the subject 101 facing the X-ray irradiation unit 10 when the subject 101 is placed between the X-ray irradiation unit 10 and the X-ray detection unit 20. The optical imaging control unit 32 also displays an irradiation unit angle display area 92 on the display operation unit 41, which displays the angle of the X-ray irradiation unit 10 relative to the imaging table 21 (see FIG. 1) or the imaging stand 22 (see FIG. 1).

[0051] (Display of Optical Image in Second Mode) Next, with reference to FIG. 7, a configuration in which the optical imaging control unit 32 (see FIG. 3) displays the optical image 70 in the second mode will be described.

[0052] In the second mode, the optical imaging control unit 32 displays the optical image 70 on which a region display 80 based on the position on the body surface 101 a of the subject 101 in real space (see FIG. 1 ) is superimposed. In the first embodiment, when displaying the optical image 70 in the second mode, the optical imaging control unit 32 is configured to control the display operation unit 41 to display the region display 80 including the detection unit region display 81, the X-ray irradiation field region display 84, and the AEC region display 87 superimposed on the optical image 70. Note that the second mode is a mode in which the optical image 70 on which the region display 80 is superimposed on the body surface 101 a of the subject 101 is displayed on the display operation unit 41 when adjusting the position of the X-ray irradiator 10. In the first embodiment, when displaying the optical image 70 in the second mode, the optical imaging control unit 32 is configured to control the display operation unit 41 to display the optical image 70 in which the area display 80 deformed according to the body thickness of the subject 101 is superimposed based on the position on the body surface 101a of the subject 101 in real space.

[0053] (Switching Between First Mode and Second Mode) The optical imaging control unit 32 is configured to perform control to switch from the first mode to the second mode based on an input from the operator received by the input receiving unit 43 (see FIG. 3) when performing position adjustment. In the first embodiment, the optical imaging control unit 32 is configured to perform control to switch the mode for displaying the optical image 70 from the first mode to the second mode based on receiving an operation input to turn on the light source unit 33 (see FIG. 3).

[0054] 6 and 7 , the optical imaging control unit 32 is configured to perform control such that the display mode of the region display 80 (detector region display 81, X-ray radiation field region display 84, and AEC region display 87) in the first mode and the display mode of the region display 80 (detector region display 81, X-ray radiation field region display 84, and AEC region display 87) in the second mode are made different from each other and are superimposed on the optical image 70 and displayed on the display operation unit 41. The optical imaging control unit 32 makes the display mode of the region display 80 different by, for example, changing the shape and / or color of the region display 80 (detector region display 81, X-ray radiation field region display 84, and AEC region display 87). 6 and 7 , the detection unit region display 81, the X-ray irradiation field region display 84, and the AEC region display 87 are hatched differently to illustrate the differences in color among the detection unit region display 81, the X-ray irradiation field region display 84, and the AEC region display 87. Note that in FIGS. 6 and 7 , the display manner of the pair of dotted line displays 86 in the X-ray irradiation field region display 84 is not different between the first mode and the second mode. However, the display manner of the pair of dotted line displays 86, together with the region display 85, which is a rectangular frame line, may be different between the first mode and the second mode. In the first embodiment, the optical imaging control unit 32 switches between the first mode and the second mode based on the illumination of the light source unit 33. Therefore, the optical image 70 in the first mode shown in FIG. 6 does not include the irradiation field region 33 a, but the optical image 70 in the second mode shown in FIG. 7 includes the irradiation field region 33 a.

[0055] Furthermore, in the first embodiment, since the fixed position in the first mode is the surface of the X-ray detection unit 20, the area display 80 (detection unit area display 81, X-ray irradiation field area display 84, and AEC area display 87) superimposed on the optical image 70 shown in Figure 6 is smaller in size than the area display 80 (detection unit area display 81, X-ray irradiation field area display 84, and AEC area display 87) superimposed on the optical image 70 shown in Figure 7.

[0056] In the first mode, the detection unit region display 81, the X-ray irradiation field region display 84, and the AEC region display 87 are displayed based on a predetermined fixed position in real space, which is a preset position in the X-ray irradiation direction, when the X-ray irradiator 10 and the X-ray detector 20 face each other, regardless of the position of the body surface 101a of the subject 101 (see FIG. 1 ). Therefore, when the optical imaging control unit 32 superimposes the detection unit region display 81, the X-ray irradiation field region display 84, and the AEC region display 87 in the first mode, the optical imaging control unit 32 superimposes them in lighter colors, for example. In addition, in the second mode, the detection unit region display 81, the X-ray irradiation field region display 84, and the AEC region display 87 are superimposed on the body surface 101a of the subject 101. Therefore, in the second mode, the optical imaging control unit 32 superimposes the detection unit region display 81, the X-ray irradiation field region display 84, and the AEC region display 87 in darker colors. That is, the optical imaging control unit 32 changes the display mode of the area display 80 (detection unit area display 81, X-ray irradiation field area display 84, and AEC area display 87) based on the difference in accuracy of position and shape between the first mode and the second mode.

[0057] In the first embodiment, as shown in FIGS. 6 and 7 , the optical imaging control unit 32 may be configured to switch between the first mode and the second mode based on a mode switching button 44 displayed on the display operation unit 41. The mode switching button 44 is a button of a GUI (Graphical User Interface) displayed on the display operation unit 41. The mode switching button 44 includes a first mode switching button 44a and a second mode switching button 44b. When the first mode switching button 44a is pressed, the optical imaging control unit 32 displays the optical image 70 in the first mode. When the second mode switching button 44b is pressed, the optical imaging control unit 32 displays the optical image 70 in the second mode. This allows the operator to switch between the first mode and the second mode at any time. This improves operator convenience (usability).

[0058] (Control of Superimposed Image Based on Body Thickness of Subject) The optical imaging control unit 32 is configured to acquire the body thickness of the subject 101 based on any of the optical image 70 captured by the optical imaging unit 31, a selection operation of body thickness information of the subject 101 by the operator, and body shape information 102 (see FIG. 3 ) of the subject 101. In addition, in the second mode, the optical imaging control unit 32 is configured to perform control to cause the display operation unit 41 to display the optical image 70, which is superimposed on the region display 80 deformed according to the acquired body thickness of the subject 101, based on the position on the body surface 101 a of the subject 101 in real space.

[0059] (Calculation of Body Thickness of Subject) Next, a configuration in which the optical imaging control unit 32 calculates the body thickness of the subject 101 will be described with reference to FIGS. 8 and 9. FIG.

[0060] As shown in Figures 8 and 9, the optical imaging control unit 32 (see Figure 3) calculates the X-ray tube-subject distance D1 between the X-ray tube 11 (the focal point) and the subject 101 based on the coordinates of the center of a predetermined position 33c of the irradiation field area 33a that appears on the body surface of the subject 101 in the optical image 70 captured by the optical imaging unit 31 (see Figure 3).

[0061] Specifically, the optical imaging control unit 32 (see FIG. 3 ) calculates a detector-to-body-surface distance D3 between the X-ray detection unit 20 and the body surface of the subject 101 in the optical axis direction of the light source unit 33 (see FIG. 3 ) based on a coordinate difference D2 between the coordinate of the center of the X-ray detection unit 20 as the predetermined position 20a in the optical image 70 and the coordinate of the center of the irradiation field region 33a on the body surface of the subject 101 as the predetermined position 33c in the irradiation field region 33a shown on the body surface of the subject 101 in the optical image 70. Then, the optical imaging control unit 32 calculates an X-ray tube-to-subject distance D1 based on the calculated detector-to-body-surface distance D3 and an X-ray tube-to-detector distance D4 between the X-ray tube 11 and the X-ray detection unit 20. The X-ray tube-to-detector distance D4 is calculated by the optical imaging control unit 32 based on the positions of the X-ray irradiator 10 and the X-ray detection unit 20 acquired by the motion detection unit 50b (see FIG. 3 ).

[0062] As shown in Fig. 8, the optical axis 31c of the optical imaging unit 31 is parallel to the optical axis 33b of the light source unit 33. In other words, the optical imaging unit 31 has an optical axis that is shifted in the direction in which the optical imaging unit 31 and the X-ray irradiator 10 are aligned with respect to the irradiation axis of X-rays irradiated from the X-ray irradiator 10 (the optical axis 33b of the light source unit 33). Therefore, as shown in Fig. 9, in the optical image 70, the center of the X-ray detection unit 20 as the predetermined position 20a is shifted from the center of the irradiation field region 33a shown on the body surface of the subject 101 as the predetermined position 33c. Therefore, the optical imaging control unit 32 (see Fig. 3) first calculates a coordinate difference D2 between the coordinate of the center of the X-ray detection unit 20 as the predetermined position 20a in the optical image 70 and the coordinate of the center of the irradiation field region 33a shown on the body surface of the subject 101 as the predetermined position 33c in the optical image 70. 8, the imaging range 31b of the optical imaging unit 31 is indicated by a dashed line. The imaging range 31b of the optical imaging unit 31 is set to include the range of the irradiation field irradiated with X-rays and to be larger than the range of the irradiation field of X-rays.

[0063] Next, as shown in FIG. 8 , the optical imaging control unit 32 (see FIG. 3 ) calculates a detector-body-surface distance D3 between the X-ray tube 11 and the X-ray detection unit 20 from the equation tan θ = (coordinate difference D2 / detector-body-surface distance D3), where θ is the angle between the optical axis 33b of the light source unit 33 and a line connecting the optical imaging unit 31 and the center 20b of the X-ray detection unit 20. That is, the optical imaging control unit 32 calculates the detector-body-surface distance D3 in the optical axis direction of the X-ray tube 11 based on the coordinate difference D2 as well as the angle θ between the optical axis 33b of the light source unit 33 and a line connecting the optical imaging unit 31 and the center 20b of the X-ray detection unit 20. The body thickness of the subject 101 is a distance D6 obtained by subtracting a detector-body-back surface distance D5 from the X-ray detection unit 20 to the (back surface of) the subject 101 in the optical axis direction of the light source unit 33 from the detector-body-surface distance D3. The detector-body-back surface distance D5 is calculated from the arrangement of the X-ray detection units 20 held on the imaging table 21 and the thickness of the imaging table 21 in the optical axis direction of the light source unit 33. The arrangement of the X-ray detection units 20 held on the imaging table 21 and the thickness of the imaging table 21 in the optical axis direction of the light source unit 33 are known values. Therefore, the optical imaging control unit 32 calculates the detector-body-back surface distance D5 from the arrangement of the X-ray detection units 20, which are known values, and the thickness of the imaging table 21 in the optical axis direction of the light source unit 33. The optical imaging control unit 32 then obtains a distance D6 calculated by subtracting the detector-body-back surface distance D5 from the detector-body-front surface distance D3 as the body thickness of the subject 101.

[0064] In the first embodiment, the optical imaging control unit 32 calculates the X-ray tube-to-subject distance D1 by subtracting the detector-to-body surface distance D3 from the X-ray tube-to-detector distance D4. As shown in Fig. 7 , the optical imaging control unit 32 displays the calculated X-ray tube-to-subject distance D1 in the SOD display area 91. The optical imaging control unit 32 also displays the X-ray tube-to-detector distance D4 in the SID display area 90.

[0065] (Acquisition of Body Thickness by Selecting Body Thickness Information) As shown in FIGS. 6 and 7 , the optical imaging control unit 32 (see FIG. 3 ) may be configured to acquire the body thickness of the subject 101 based on an input from the operator operating the body thickness level selection button 45. The body thickness level selection button 45 is a GUI button displayed on the display operation unit 41. The body thickness level selection button 45 includes a “large” button 45 a, a “medium” button 45 b, and a “small” button 45 c. The optical imaging control unit 32 acquires a predetermined value corresponding to the “large” button 45 a, the “medium” button 45 b, or the “small” button 45 c as the body thickness of the subject 101. Then, when displaying the optical image 70 in the second mode, the optical imaging control unit 32 displays a region display 80 on the body surface 101 a of the subject 101 based on the body thickness corresponding to the selected body thickness level selection button 45.

[0066] For example, if "60 cm," "40 cm," and "20 cm" are stored in the memory 60a (see FIG. 3) as values ​​corresponding to the "large" button 45a, the "medium" button 45b, and the "small" button 45c, respectively, pressing the "medium" button 45b causes the optical imaging control unit 32 to set a position 40 cm away from the surface of the X-ray detection unit 20 toward the X-ray irradiation unit 10 as the body surface 101a of the subject 101. Then, the optical imaging control unit 32 displays, on the display operation unit 41, an optical image 70 with a region display 80 superimposed thereon at a position 40 cm away from the surface of the X-ray detection unit 20 toward the X-ray irradiation unit 10. Note that the above values ​​corresponding to the "large" button 45a, the "medium" button 45b, and the "small" button 45c are merely examples, and different values ​​may be set.

[0067] (Calculation of Body Thickness Based on Body Type Information of Subject) The optical imaging control unit 32 may acquire the body thickness of the subject 101 based on the body type information 102 (see FIG. 3 ) of the subject 101. Specifically, the optical imaging control unit 32 calculates the body thickness of the subject 101 using a known calculation formula from the height and weight of the subject 101 included in the body type information 102 of the subject 101. Then, when displaying the optical image 70 in the second mode, the optical imaging control unit 32 displays an area display 80 or the like on the body surface 101 a of the subject 101 based on the body thickness calculated based on the body type information 102 of the subject 101.

[0068] (Image Display Method) Next, the control processing of the image display method by the X-ray imaging apparatus 100 (see FIG. 1) of the first embodiment will be described with reference to Fig. 10. The control processing of the image display method by steps 201 to 208 is executed by the optical imaging control unit 32 (see FIG. 3).

[0069] First, in step 201, an optical image 70 (see FIG. 4) is acquired by the optical imaging unit 31 (see FIG. 3).

[0070] Next, in step 202, based on signals from the device control unit 60 (see FIG. 3), the three-dimensional positions of the X-ray irradiation unit 10 (see FIG. 3) and the X-ray detection unit 20 (see FIG. 3) are obtained, and the three-dimensional position of the optical imaging unit 31 is calculated and obtained. Furthermore, based on the three-dimensional position of the X-ray detection unit 20, the three-dimensional position of the AEC 23 (see FIG. 1) is also calculated and obtained.

[0071] Next, in step 203, the area in the optical image 70 where the X-ray detection unit 20 is located, the area where the X-rays are irradiated (the irradiation field area 33a (see Figure 4)), and the area where the AEC 23 is located are calculated.

[0072] Next, the fixation position is acquired in step 204. In the first embodiment, the fixation position may be acquired based on the position information 103 of the X-ray detection unit 20 (see FIG. 3 ) or based on the standard body thickness information 104.

[0073] Next, in step 205, as shown in FIG. 6 , the optical image 70 is displayed on the display operation unit 41, with the area display 80 (detection unit area display 81, X-ray irradiation field area display 84, and AEC area display 87) superimposed thereon, based on a predetermined fixed position in real space.

[0074] Next, in step 206, it is determined whether or not there has been an operation input to operate the light source unit 33. If there has been an operation input to operate the light source unit 33, the process proceeds to step 207. If there has been no operation input to operate the light source unit 33, the process of step 206 is repeated.

[0075] Next, in step 207, the optical imaging control unit 32 acquires the body thickness of the subject 101. The optical imaging control unit 32 acquires the body thickness of the subject 101 based on the optical image 70. The optical imaging control unit 32 may acquire the body thickness of the subject 101 based on an operation input of the body thickness level selection button 45 (see FIG. 6). The optical imaging control unit 32 may also acquire the body thickness of the subject 101 based on the body type information 102 of the subject 101 (see FIG. 3).

[0076] Next, in step 208, the optical imaging control unit 32 displays the optical image 70 on which the region displays 80 (detector region display 81, X-ray irradiation field region display 84, and AEC region display 87) are superimposed, based on the position on the body surface 101 a of the subject 101 in real space, on the display operation unit 41. Thereafter, the processing ends.

[0077] It should be noted that either the control process of step 201 or step 202 may be executed first.

[0078] (Effects of First Embodiment) In the first embodiment, the following effects can be obtained.

[0079] As described above, in the first embodiment, the X-ray imaging apparatus 100 includes the X-ray irradiator 10 including the X-ray tube 11, the X-ray detector 20 that detects X-rays irradiated from the X-ray irradiator 10 and transmitted through the subject 101, the optical imaging unit 31 that captures an optical image 70 of the subject 101, the display operation unit 41 that displays the optical image 70 captured by the optical imaging unit 31, the optical imaging controller 32 that controls the display of the optical image 70 on the display operation unit 41, and the input receiver 43 that receives input from an operator. When performing position adjustment, the optical imaging controller 32 controls the position of the X-ray detector 20 in the optical image 70 based on the operator's input received by the input receiver 43, using a predetermined fixed position in real space as a reference. the optical image 70 is displayed with a region display 80 superimposed thereon, the region display 80 including at least one of a detection unit region display 81 indicating the region where the X-rays are located, an X-ray irradiation field region display 84 indicating the region in the optical image 70 where X-rays are irradiated by the X-ray irradiation unit 10, and an AEC region display 87 indicating the region in the optical image 70 where the X-rays irradiated by the X-ray irradiation unit 10 are collected, or the optical image 70 is displayed without the region display 80 being superimposed on the optical image 70, to a second mode in which the optical image 70 is displayed with the region display 80 superimposed thereon, the region display 80 being based on the position on the body surface 101 a of the subject 101 in real space.

[0080] As a result, when the optical image 70 with the region display 80 superimposed thereon is displayed in the first mode, the optical image 70 with the region display 80 superimposed thereon is displayed at a fixed position, so that even if the position of the body surface 101 a of the subject 101 changes when roughly adjusting the position of the subject 101 and the X-ray irradiator 10, the region display 80 can be fixed and displayed. Therefore, it is possible to prevent the position and shape of the region display 80 from changing, which can prevent a decrease in the efficiency of the position adjustment work caused by the position and shape of the region display 80 being frequently changed when roughly adjusting the position of the subject 101 and the X-ray irradiator 10. Furthermore, when the optical image 70 with the region display 80 not superimposed thereon is displayed in the first mode, the region display 80 is not superimposed on the optical image 70, so that it can prevent a decrease in the efficiency of the position adjustment work caused by the position and shape of the region display 80 being frequently changed when roughly adjusting the position of the subject 101 and the X-ray irradiator 10. Furthermore, after roughly adjusting the positions of the subject 101 and the X-ray irradiator 10, the operator fine-tunes the positions of the subject 101 and the X-ray irradiator 10. In fine-tuning the positions of the subject 101 and the X-ray irradiator 10, the positions of the subject 101 and the X-ray irradiator 10 are adjusted so that the irradiation area of ​​the X-rays irradiated on the body surface of the subject 101 corresponds to the detection area of ​​the X-ray detection unit 20. In the second mode, which is switched from the first mode based on input from the operator, the optical image 70 is displayed with the region display 80 superimposed on the body surface 101a of the subject 101. Therefore, when fine-tuning the positions of the subject 101 and the X-ray irradiator 10, the operator can easily adjust the positions while visually recognizing the region display 80 superimposed on the body surface 101a of the subject 101 in the optical image 70. As a result, it is possible to provide an X-ray imaging apparatus 100 that allows easy position adjustment while suppressing a decrease in work efficiency.

[0081] Furthermore, in the first embodiment, the following additional effects can be obtained by configuring as follows.

[0082] That is, in the first embodiment, as described above, the first mode is a mode in which, when adjusting the position of the subject 101, the optical image 70 on which the region display 80 based on a fixed position as a reference is superimposed is displayed on the display operation unit 41 (display unit), and the second mode is a mode in which, when adjusting the position of the X-ray irradiator 10, the optical image 70 on which the region display 80 based on the position on the body surface 101 a of the subject 101 in real space as a reference is superimposed is displayed on the display operation unit 41. Here, when adjusting the position of the subject 101, there is a case in which the position of the subject 101 is adjusted while visually recognizing the position of the X-ray detection unit 20 as a guide for the position adjustment. Therefore, with the above-described configuration, when adjusting the position of the subject 101, the optical image 70 on which the region display 80 based on a fixed position as a reference is superimposed is displayed in the first mode, so that the position of the subject 101 can be adjusted while visually recognizing the region display 80 as a guide for the position adjustment. In this case, even if the position of the body surface 101a of the subject 101 changes, the region display 80 remains fixed, thereby preventing a decrease in work efficiency in adjusting the position of the subject 101 due to frequent changes in the position and shape of the region display 80. Furthermore, when adjusting the position of the X-ray irradiator 10, the second mode displays the optical image 70 on which the region display 80 based on the position on the body surface 101a of the subject 101 is superimposed. Therefore, when adjusting the position of the X-ray irradiator 10, the operator can easily adjust the position of the X-ray irradiator 10 by visually recognizing the region display 80 superimposed on the optical image 70.

[0083] Furthermore, in the first embodiment, as described above, when displaying the optical image 70 in the second mode, the optical imaging control unit 32 (control unit) is configured to control the display operation unit 41 (display unit) to display the optical image 70, which is superimposed on the body surface 101a of the subject 101 in real space, with the area display 80 deformed according to the body thickness of the subject 101 as a reference.

[0084] Here, the region display 80 includes any one of a detection unit region display 81, which is a region of X-rays irradiated to the subject 101 that are detected by the X-ray detection unit 20, an X-ray irradiation field region display 84, which indicates a region of X-rays irradiated from the X-ray irradiator 10 (irradiation field region 33a), and an AEC region display 87, which indicates a region that collects X-rays irradiated by the X-ray irradiator 10. Therefore, as described above, by displaying on the display operation unit 41 an optical image 70 in which the region display 80, which has been deformed according to the body thickness of the subject 101, is superimposed based on the position on the body surface 101a of the subject 101 in real space, when the region display 80 includes the detection unit region display 81, the operator can visually recognize the optical image 70 and easily confirm the region in which the X-rays that have passed through the subject 101 are detected by the X-ray detection unit 20. As a result, by adjusting the position of the X-ray irradiator 10 while visually recognizing the detection unit region display 81 included in the region display 80 displayed on the body surface 101a of the subject 101, the operator can easily adjust the position of the X-ray irradiator 10 to an appropriate position according to the body thickness of the subject 101. Furthermore, when the region display 80 includes the X-ray irradiation field region display 84, the operator can easily confirm the irradiation field region 33a of the X-rays irradiated onto the body surface 101a of the subject 101 by visually recognizing the optical image 70. As a result, by adjusting the position of the X-ray irradiator 10 while visually recognizing the X-ray irradiation field region display 84 included in the region display 80 displayed on the body surface 101a of the subject 101, the operator can easily adjust the position of the X-ray irradiator 10 to an appropriate position according to the body thickness of the subject 101. Furthermore, when the region display 80 includes the AEC region display 87, the operator can easily confirm the region where the AEC 23 for collecting X-rays irradiated from the X-ray irradiator 10 is disposed by visually recognizing the optical image 70. As a result, by adjusting the position of the X-ray irradiation unit 10 while visually recognizing the AEC region display 87 included in the region display 80 displayed on the body surface 101a of the subject 101, the positions of the X-ray irradiation unit 10 and the X-ray detection unit 20 can be easily adjusted to be in an appropriate position according to the body thickness of the subject 101.

[0085] As described above, the first embodiment further includes a light source unit 33 that irradiates visible light onto an irradiation field region 33a indicating an area irradiated with X-rays by the X-ray irradiator 10. The input receiver 43 is configured to receive an operation input for turning on the light source unit 33. The optical imaging controller 32 (controller) is configured to control switching the mode for displaying the optical image 70 from the first mode to the second mode based on the reception of the operation input for turning on the light source unit 33. When adjusting the positions of the subject 101 and the X-ray irradiator 10, the subject 101 is roughly positioned, and then the X-ray irradiator 10 is finely positioned. At this time, the collimator unit 12 also adjusts the X-ray irradiation field. The adjustment of the irradiation field of the collimator unit 12 is performed by operating the collimator unit 12 while irradiating visible light from the light source unit 33, rather than irradiating X-rays. That is, the operator turns on the light source unit 33 after roughly adjusting the position of the subject 101. Therefore, with the above configuration, the operator can naturally perform an operation (pressing the input receiving unit 43) that serves as a trigger for switching between the first mode and the second mode during a series of operations that involves adjusting the position of the X-ray irradiator 10 and adjusting the X-ray irradiation field by the collimator unit 12 after roughly adjusting the position of the subject 101. As a result, the operator can smoothly perform an operation for switching between the first mode and the second mode while performing the position adjustment work, thereby preventing a decrease in the ease of the position adjustment work by the operator.

[0086] Furthermore, in the first embodiment, as described above, the optical imaging control unit 32 (control unit) is configured to control the display operation unit 41 (display unit) to display the detection unit region display 81, the X-ray irradiation field region display 84, and the AEC region display 87 (X-ray irradiation field region display) as the region display 80 superimposed on the optical image 70 when displaying the optical image 70 in the second mode. This allows the operator to visually recognize the optical image 70 on which the detection unit region display 81, the X-ray irradiation field region display 84, and the AEC region display 87 are superimposed, thereby confirming the arrangement of the X-ray irradiation field relative to the region where X-rays are detected. Therefore, in addition to the arrangement of the subject 101 in the region where X-rays are detected, the arrangement of the X-ray irradiation field relative to the region where X-rays are detected can also be confirmed based on the optical image 70 on which the detection unit region display 81, the X-ray irradiation field region display 84, and the AEC region display 87 are superimposed. Furthermore, when adjusting the irradiation field of the X-rays irradiated from the X-ray tube 11 of the X-ray irradiation unit 10 using the collimator unit 12, the operator can easily adjust the irradiation field of the X-rays using the collimator unit 12 by visually recognizing the X-ray irradiation field area display 84 displayed superimposed on the optical image 70.

[0087] Furthermore, in the first embodiment, as described above, the optical imaging control unit 32 (control unit) is configured to control the display operation unit 41 (display unit) to display the region display 80 in a different display mode in the first mode and a different display mode in the second mode so that the region display 80 is superimposed on the optical image 70. As a result, the display mode of the region display 80 differs between the first mode and the second mode, allowing the operator to easily visually recognize whether the optical image 70 in the first mode or the optical image 70 in the second mode is being displayed on the display operation unit 41. Furthermore, the region display 80 in the first mode is displayed based on a predetermined fixed position in real space, which is a position that is preset in the X-ray irradiation direction when the X-ray irradiator 10 and the X-ray detector 20 are opposed to each other. Therefore, for example, by displaying the region display 80 in a lighter color, the operator can visually recognize that the position and shape of the region display 80 are not accurate. Furthermore, for example, by displaying the area display 80 in a darker color in the second mode, the operator can visually recognize the high accuracy of the position and shape of the area display 80. As a result, the convenience (usability) for the operator can be improved.

[0088] Furthermore, in the first embodiment, as described above, the optical imaging control unit 32 (control unit) is configured to acquire the body thickness of the subject 101 based on any of the optical image 70 captured by the optical imaging unit 31, the operator's selection operation of the body thickness information of the subject 101, and the body shape information 102 of the subject 101, and in the second mode, to control the display operation unit 41 (display unit) to display the optical image 70 in which the region display 80 deformed according to the acquired body thickness of the subject 101 is superimposed based on the position on the body surface 101 a of the subject 101 in real space. As a result, when the body thickness of the subject 101 is acquired based on the optical image 70 captured by the optical imaging unit 31, the body thickness of the subject 101 can be acquired without the operator having to perform an operation input by capturing the optical image 70. Furthermore, when the body thickness of the subject 101 is acquired based on the body shape information 102 of the subject 101, the body thickness of the subject 101 can be acquired without the operator having to perform a selection operation. As a result, an increase in the burden on the operator can be suppressed. Furthermore, when the body thickness of the subject 101 is acquired by the operator selecting the body thickness information of the subject 101, the body thickness of the subject 101 can be acquired without calculating the body thickness of the subject 101. As a result, the processing load on the optical imaging control unit 32 can be reduced compared to when the optical imaging control unit 32 acquires the body thickness of the subject 101.

[0089] Furthermore, in the first embodiment, as described above, the optical imaging control unit 32 (control unit) is configured to control the display operation unit 41 (display unit) to superimpose the region display 80 based on a fixed position on the optical image 70 and display it based on the position information 103 of the X-ray detection unit 20 or the standard body thickness information 104 set in advance for each imaging region of the subject 101, when superimposing the region display 80 on the optical image 70 in the first mode. As a result, when the region display 80 based on a fixed position is superimposed on the optical image 70 based on the position information 103 of the X-ray detection unit 20, the region display 80 can always be displayed at the position of the X-ray detection unit 20, regardless of the imaging region of the subject 101. Furthermore, because the position information 103 of the X-ray detection unit 20 can be acquired by the motion detection unit 50b, the region display 80 can be easily superimposed on the position of the X-ray detection unit 20. Furthermore, when the region display 80 based on a fixed position is superimposed on the optical image 70 based on the standard body thickness information 104, the region display 80 can be superimposed at a position corresponding to the average body thickness for the imaging region using the standard body thickness information 104, which is information on the body thickness based on statistical values ​​(average values) for each imaging region of the subject 101. Furthermore, when imaging the subject 101 using the X-ray imaging device 100, the operator performs an operation to select the imaging region of the subject 101. Therefore, based on the operation of the operator to select the imaging region, it is possible to obtain the standard body thickness information 104 for the imaging region, and the region display 80 can be easily superimposed at a position corresponding to the average body thickness for the imaging region.

[0090] Furthermore, in the first embodiment, as described above, the holding unit 40 that holds the X-ray irradiator 10 is further provided, and the optical imaging unit 31 is provided in the holding unit 40 together with the X-ray irradiator 10. As a result, since both the X-ray irradiator 10 and the optical imaging unit 31 are provided in the holding unit 40, the irradiation direction of the X-rays irradiated from the X-ray irradiator 10 and the imaging direction of the optical imaging unit 31 can be aligned. Therefore, the position of the subject 101 and the position of the X-ray irradiator 10 can be easily adjusted by referring to the optical image 70 captured by the optical imaging unit 31.

[0091] Second Embodiment Next, an X-ray imaging apparatus 300 according to a second embodiment will be described with reference to FIGS.

[0092] The X-ray imaging apparatus 300 according to the second embodiment differs from the X-ray imaging apparatus 100 according to the first embodiment in that it includes an optical imaging control unit 301 instead of the optical imaging control unit 32 .

[0093] The optical imaging control unit 301 is configured to switch the mode in which the area display 80 is superimposed on the optical image 70 from the second mode to the first mode based on the operator's input received by the input receiving unit 43 or the optical image 70.

[0094] Specifically, the optical imaging control unit 301 switches from the second mode to the first mode when the completion of imaging or a change in the position of the body surface of the subject 101 is detected based on an input from the operator received by the input receiving unit 43. The optical imaging control unit 301 is also configured to switch from the second mode to the first mode based on a change in the position of the body surface of the subject 101 acquired based on the optical image 70 or based on the crosshairs 33d (see FIG. 12 ) that appear in the optical image 70.

[0095] Here, after imaging of a predetermined imaging region of the subject 101 is completed, there is a case where another imaging region is subsequently imaged. When another imaging region is subsequently imaged, the position of the subject 101 is adjusted again. Furthermore, when imaging a subject other than the subject 101 after imaging of the subject 101 is completed, the position of the different subject is adjusted. That is, after imaging of the subject 101 is completed, the position of the subject is adjusted again. When the mode in which the region display 80 is displayed superimposed on the optical image 70 is the second mode, the position and shape of the region display 80 frequently change during the position adjustment of the subject 101. In this case, the efficiency of the position adjustment work decreases due to the frequently changing position and shape of the region display 80 being displayed.

[0096] Therefore, in the second embodiment, the optical imaging control unit 301 switches from the second mode to the first mode when imaging of the subject 101 is completed. Note that the optical imaging control unit 301 determines whether imaging is completed when the input receiving unit 43 receives an input from the operator to irradiate X-rays, or when the optical imaging control unit 301 acquires information about X-ray irradiation. Alternatively, the optical imaging control unit 301 may determine that imaging is completed based on an operation input by the operator indicating that imaging is completed.

[0097] Furthermore, for example, if the subject 101 moves after the position adjustment of the subject 101 is completed, the position of the subject 101 may be adjusted again. In this case, if the mode in which the region display 80 is displayed superimposed on the optical image 70 is the second mode, the position and shape of the region display 80 are frequently changed and displayed, which reduces the efficiency of the position adjustment work.

[0098] Therefore, in the second embodiment, the optical imaging control unit 301 is configured to switch from the second mode to the first mode based on a change in the position of the body surface 101a of the subject 101. Specifically, the optical imaging control unit 301 switches from the second mode to the first mode when the range of change in the X-ray tube-subject distance D1 (see FIG. 9 ), which is the distance between the X-ray irradiator 10 and the body surface 101a of the subject 101, goes out of a predetermined range. Note that the optical imaging control unit 301 may also be configured to switch from the second mode to the first mode based on an operation input by the operator indicating that the change in the position of the body surface 101a of the subject 101 has increased.

[0099] Furthermore, similar to the optical imaging control unit 32 according to the first embodiment, the optical imaging control unit 301 calculates the X-ray tube-subject distance D1 between the X-ray tube 11 (the focal point of the X-ray tube) and the subject 101 based on the coordinates of the center of the irradiation field region 33a (see FIG. 4 ) as the predetermined position 33c (see FIG. 8 ). In this case, as shown in FIG. 12 , the optical imaging control unit 301 uses the coordinates of the center of the crosshairs 33d in the irradiation field region 33a as the predetermined position 33c to calculate the X-ray tube-subject distance D1. If the contrast of the crosshairs 33d is low in the irradiation field region 33a, it becomes difficult to accurately determine the center position of the irradiation field region 33a. Therefore, it becomes difficult for the optical imaging control unit 301 to accurately determine the X-ray tube-subject distance D1. If it is difficult to accurately determine the X-ray tube-subject distance D1, it becomes difficult to accurately superimpose the region display 80 on the body surface 101a of the subject 101 in the optical image 70. Therefore, in the second embodiment, the optical imaging control unit 301 is configured to switch from the second mode to the first mode when the contrast of the crosshairs 33d in the irradiation field region 33a decreases.

[0100] Next, referring to Figure 13, we will explain the process by which the optical imaging control unit 301 (see Figure 11) switches the mode in which the area display 80 (see Figure 5) is superimposed on the optical image 70 (see Figure 5) from the second mode to the first mode.

[0101] In step 310, the optical imaging control unit 301 displays the region display 80 in the second mode, superimposed on the optical image 70. Note that the processing in step 310 is similar to the processing in steps 201 to 208 shown in Fig. 10 performed by the optical imaging control unit 32 according to the first embodiment, and therefore a detailed description thereof will be omitted.

[0102] Next, in step 311, the optical imaging control unit 301 determines whether or not a state has been reached where it should be switched to the first mode. Specifically, the optical imaging control unit 301 determines whether or not a state has been reached where it should be switched to the first mode based on the operator's input accepted by the input accepting unit 43 or the optical image 70. If it is to be switched to the first mode, the process proceeds to step 312. If it is not to be switched to the first mode, the optical imaging control unit 301 repeats the process of step 311.

[0103] In step 312, the optical imaging control unit 301 switches the mode for displaying the region display 80 superimposed on the optical image 70 from the second mode to the first mode, after which the processing ends.

[0104] The other configurations of the second embodiment are similar to those of the first embodiment.

[0105] Effect of Second Embodiment In the second embodiment, as described above, the optical imaging control unit 301 is configured to switch the mode in which the region display 80 is superimposed on the optical image 70 from the second mode to the first mode based on the operator's input received by the input receiving unit 43 or the optical image 70. As a result, when a situation arises in which switching from the second mode to the first mode is necessary, such as when another imaging region is subsequently imaged after imaging is completed, when the position of the subject 101 is adjusted again, or when the contrast of the crosshairs 33d in the irradiation field region 33a displayed in the optical image 70 decreases, the mode in which the region display 80 is superimposed can be switched from the second mode to the first mode without the operator performing a mode switching operation. As a result, even when a situation arises in which switching from the second mode to the first mode is necessary, it is possible to prevent a decrease in the efficiency of the position adjustment work due to the position and shape of the region display 80 being frequently changed, as compared to a configuration in which switching from the second mode to the first mode is not performed.

[0106] The other effects of the second embodiment are the same as those of the first embodiment.

[0107] Third Embodiment Next, an X-ray imaging apparatus 400 according to a third embodiment will be described with reference to FIG.

[0108] The X-ray imaging apparatus 400 according to the third embodiment differs from the X-ray imaging apparatus 100 according to the first embodiment in that it has an optical imaging unit 401 and an optical imaging control unit 402 instead of the optical imaging unit 31 and the optical imaging control unit 32.

[0109] The optical imaging unit 401 differs from the optical imaging unit 31 according to the first embodiment in that it acquires the position of the body surface 101a of the subject 101 in real space. The optical imaging unit 401 is an example of a "body surface position acquisition unit" in the claims. In the third embodiment, the optical imaging unit 401 has the functions of both an optical imaging unit that captures an optical image 70 of the subject 101 and a body surface position acquisition unit that acquires the position of the body surface 101a of the subject 101 in real space. The X-ray imaging apparatus 400 according to the third embodiment may include a 3D sensor capable of measuring a position in the depth direction as the body surface position acquisition unit.

[0110] Furthermore, the optical imaging control unit 402 according to the third embodiment is configured to perform control to display the optical image 70 on which is superimposed a region display 80 including at least one of a detection unit region display 81 indicating the region in the optical image 70 where the X-ray detection unit 20 is located, an X-ray irradiation field region display 84 indicating the region in the optical image 70 to which X-rays are irradiated by the X-ray irradiator 10, and an AEC region display 87 indicating the region in the optical image 70 to which the X-rays irradiated by the X-ray irradiator 10 are collected, based on an input from the operator received by the input receiving unit 43 or the position of the body surface 101 a of the subject 101 acquired by the optical imaging unit 401, using a predetermined fixed position in real space as a reference, or to switch from a first mode in which the region display 80 is not superimposed on the optical image 70 to a second mode in which the optical image 70 is displayed on which is superimposed a region display 80 based on the position on the body surface 101 a of the subject 101 in real space as a reference. That is, the optical imaging control unit 402 according to the third embodiment is configured to be able to perform both manual switching from the first mode to the second mode by an operator performing an operation input, and automatic switching from the first mode to the second mode based on the position of the body surface 101a of the subject 101 acquired by the optical imaging unit 401.

[0111] The configuration in which the optical imaging control unit 402 switches from the first mode to the second mode based on the operator's input received by the input receiving unit 43 is similar to the configuration in which the optical imaging control unit 32 in the first embodiment switches from the first mode to the second mode based on the operator's input received by the input receiving unit 43, so detailed explanation will be omitted.

[0112] Therefore, in the third embodiment, a configuration will be described in which the optical imaging control unit 402 switches from the first mode to the second mode based on the position of the body surface 101 a of the subject 101 acquired by the optical imaging unit 401 .

[0113] Here, when the position adjustment of the subject 101 is completed, the position of the body surface 101a of the subject 101 remains substantially stationary at a predetermined position. Therefore, in the third embodiment, the optical imaging control unit 402 is configured to switch from the first mode to the second mode based on the position of the body surface 101a of the subject 101 captured in the optical image 70.

[0114] In the third embodiment, the optical imaging control unit 402 acquires the X-ray tube-subject distance D1 based on the position of the body surface 101a of the subject 101 captured in the optical image 70. Note that the configuration by which the optical imaging control unit 402 acquires the X-ray tube-subject distance D1 is similar to the configuration by which the optical imaging control unit 32 according to the first embodiment acquires the X-ray tube-subject distance D1, and therefore detailed description thereof will be omitted. The optical imaging control unit 402 is configured to switch from the first mode to the second mode based on the amount of variation in the acquired X-ray tube-subject distance D1. Specifically, the optical imaging control unit 402 switches from the first mode to the second mode when the amount of variation in the X-ray tube-subject distance D1 falls within a predetermined range.

[0115] The optical imaging control unit 402 may be configured to switch from the first mode to the second mode based on the subject 101 appearing in the optical image 70. That is, the optical imaging control unit 402 may be configured to determine whether or not position adjustment of the subject 101 has been completed by performing image analysis of the subject 101 appearing in the optical image 70, and to switch from the first mode to the second mode when position adjustment of the subject 101 has been completed.

[0116] Furthermore, if the position of the X-ray irradiator 10 changes after the position adjustment of the subject 101 is completed, the X-ray tube-to-subject distance D1 also changes. Therefore, the optical imaging control unit 402 is configured to switch from the second mode to the first mode when the amount of change in the X-ray tube-to-subject distance D1 falls outside the predetermined range due to movement of the X-ray irradiator 10 after the amount of change in the X-ray tube-to-subject distance D1 falls within the predetermined range. Note that the X-ray irradiator 10 is provided with a sensor (e.g., a potentiometer) that can acquire the amount of movement of the X-ray irradiator 10, and therefore the optical imaging control unit 402 can acquire the amount of movement of the X-ray irradiator 10.

[0117] Next, the control processing of the image display method by the X-ray imaging apparatus 400 (see FIG. 14) of the third embodiment will be described with reference to FIG. 15. The control processing of the image display method by steps 201 to 205, step 410, step 207, and step 208 is executed by the optical imaging control unit 402 (see FIG. 14). Note that the same processes as those executed by the optical imaging control unit 32 of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0118] In steps 201 to 205, the optical imaging control unit 402 displays the optical image 70 on which the region display 80 (detector region display 81, X-ray irradiation field region display 84, and AEC region display 87) is superimposed, based on a predetermined fixed position in real space, on the display operation unit 41. That is, the optical imaging control unit 402 sets the mode in which the region display 80 is superimposed on the optical image 70 and displayed to the first mode.

[0119] Next, in step 410, the optical imaging control unit 402 determines whether to switch from the first mode to the second mode. Specifically, the optical imaging control unit 402 determines whether to switch from the first mode to the second mode based on the position of the body surface 101a of the subject 101 acquired by the optical imaging unit 401. If the first mode is to be switched to the second mode, the process proceeds to step 207. If the first mode is not to be switched to the second mode, the optical imaging control unit 402 repeats the process of step 410.

[0120] Next, in steps 207 and 208, the optical imaging control unit 402 displays the optical image 70 on which the region display 80 (detector region display 81, X-ray irradiation field region display 84, and AEC region display 87) is superimposed, based on the position on the body surface 101a of the subject 101 in real space, on the display operation unit 41. That is, the optical imaging control unit 402 switches the mode in which the region display 80 is superimposed on the optical image 70 and displayed, from the first mode to the second mode. Then, the processing ends.

[0121] The process by which the optical imaging control unit 402 switches from the first mode to the second mode based on the operator's input received by the input receiving unit 43 is similar to the process performed by the optical imaging control unit 32 according to the first embodiment described above based on the flowchart shown in Figure 10, and therefore detailed explanation will be omitted.

[0122] The other configurations of the third embodiment are similar to those of the first embodiment.

[0123] (Effects of Third Embodiment) In the third embodiment, as described above, the X-ray imaging apparatus 400 includes the X-ray irradiator 10 including the X-ray tube 11, the X-ray detector 20 that detects X-rays irradiated from the X-ray irradiator 10 and transmitted through the subject 101, the optical imaging unit 401 that captures an optical image 70 of the subject 101 and acquires the position of the body surface 101 a of the subject 101 in real space, the display operation unit 41 that displays the optical image 70 captured by the optical imaging unit 401, the optical imaging control unit 402 that controls the display of the optical image 70 on the display operation unit 41, and the input receiving unit 43 that receives input from an operator. When adjusting the position, the optical imaging control unit 402 performs position adjustment by adjusting the position of the body surface 101 a of the subject 101 in real space based on the input of the operator received by the input receiving unit 43 or the position of the body surface 101 a of the subject 101 acquired by the optical imaging unit 401. The optical image 70 is configured to display an optical image 70 on which an area display 80 including at least one of a detection unit area display 81 indicating the area in the optical image 70 where the X-ray detection unit 20 is located, an X-ray irradiation field area display 84 indicating the area in the optical image 70 to which X-rays are irradiated by the X-ray irradiation unit 10, and an AEC area display 87 indicating the area in the optical image 70 to which the X-rays irradiated by the X-ray irradiation unit 10 are collected, based on a predetermined fixed position on the optical image 70, or to perform control to switch from a first mode in which the optical image 70 is displayed without the area display 80 being superimposed on the optical image 70, to a second mode in which the optical image 70 is displayed on which an area display 80 is superimposed, based on the position on the body surface 101 a of the subject 101 in real space.

[0124] As a result, when the optical imaging control unit 402 switches from the first mode to the second mode based on an operator input received by the input receiving unit 43, it is possible to provide an X-ray imaging apparatus 400 that can easily perform position adjustment while suppressing a decrease in work efficiency, similar to the X-ray imaging apparatus 100 according to the first embodiment. Furthermore, when the optical imaging control unit 402 switches from the first mode to the second mode based on the position of the body surface 101 a of the subject 101 acquired by the optical imaging unit 401, the first mode is switched to the second mode based on the position of the body surface 101 a of the subject 101 acquired by the optical imaging unit 401. Therefore, it is possible to automatically switch from the first mode to the second mode without the operator having to perform an operation input. As a result, it is possible to provide an X-ray imaging apparatus 400 that can easily perform position adjustment while simultaneously reducing the operator's workload and suppressing a decrease in work efficiency.

[0125] The other effects of the third embodiment are similar to those of the first embodiment.

[0126] [Modifications] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the description of the above-mentioned embodiments, and further includes all modifications (modifications) within the meaning and scope of the claims.

[0127] For example, in the above first to third embodiments, an example of a configuration was shown in which the optical imaging control unit 32 (control unit) calculates the body thickness of the subject 101 based on the coordinate difference D2 between the coordinate of the center of the predetermined position 20a of the X-ray detection unit 20 in the optical image 70 and the coordinate of the center of the predetermined position 33c of the irradiation field region 33a shown on the body surface of the subject 101 in the optical image 70, but the present invention is not limited to this. In the present invention, for example, the control unit (optical imaging control unit) may be configured to calculate the body thickness of the subject 101 based on the coordinate of the center of the predetermined position 33c of the irradiation field region 33a shown on the body surface of the subject 101 in the optical image 70, as in the modified examples shown in Figures 16 and 17.

[0128] Specifically, the control unit (optical imaging control unit) calculates an imaging unit-body-surface distance D7 between the optical imaging unit 31 and the body surface of the subject 101 in the optical axis direction of the light source unit 33 based on the coordinates of the center of the irradiation field region 33a shown on the body surface of the subject 101 in the optical image 70, the coordinates of the imaging unit coordinate system centered on the optical imaging unit 31, and a relational expression (relational expression using a matrix of internal parameters of the optical imaging unit 31) for converting the coordinates of the imaging unit coordinate system into coordinates of the image coordinate system indicating the coordinates in the optical image 70. Then, the control unit (optical imaging control unit) calculates an X-ray tube-subject distance D1 based on the calculated imaging unit-body-surface distance D7 and an X-ray tube-to-imaging unit distance D8 between the X-ray tube 11 and the optical imaging unit 31 in the optical axis direction of the light source unit 33. The X-ray tube-to-imaging unit distance D8 can be calculated based on the arrangement of the optical imaging unit 31 in the X-ray irradiation unit 10.

[0129] Furthermore, the irradiation axis direction of the X-ray irradiation unit 10 is the Z direction, and the directions perpendicular to each other in a plane perpendicular to the Z direction are the X and Y directions, respectively. The coordinates of the center of the predetermined position 33c of the irradiation field region 33a shown on the body surface of the subject 101 in the optical image 70 in the imaging unit coordinate system (Xc, Yc, Zc) with the optical imaging unit 31 as the center (origin) in real space, and the coordinates of the image coordinate system (x, y) showing the coordinates in the optical image 70 are respectively (Xch, Ych, Zch) and (xh, yh), and the following formula (1) holds. Here, K is a matrix for converting coordinates in the imaging unit coordinate system into coordinates in the image coordinate system, and is what is called a matrix of internal parameters of the optical imaging unit 31. That is, f is the focal length of the lens of the optical imaging unit 31, (Sx, Sy) is the size of the imaging element 31a of the optical imaging unit 31, and (w, h) is the number of pixels of the imaging element 31a of the optical imaging unit 31.

[0130] From the above formula (1), the following formulas (2) and (3) are derived.

[0131] The following equations (4) and (5) are derived from the above equations (2) and (3), respectively.

[0132] Thus, Zch can be calculated from the above formula (4) or (5). Zch is the Z-direction component of the coordinates of the image capture unit coordinate system with the optical image capture unit 31 as the center (origin) of the coordinates of the center as the predetermined position 33c of the irradiation field region 33a shown on the body surface of the subject 101 in the optical image 70. Zch is equal to the image capture unit-body surface distance D7.

[0133] The control unit (optical imaging control unit) then calculates the X-ray tube-to-subject distance D1 by adding the imaging unit-to-body surface distance D7 and the X-ray tube-to-imaging unit distance D8 between the X-ray tube 11 and the optical imaging unit 31 in the optical axis direction of the light source unit 33. The control unit (optical imaging control unit) then obtains the body thickness of the subject 101 by calculating a distance D6 from the X-ray tube-to-subject distance D1, the X-ray tube-to-detector unit distance D4, and the detector-to-body back surface distance D5.

[0134] In the first to third embodiments and the modified example, the optical imaging control unit 32 (control unit) calculates the body thickness of the subject 101 from the optical image 70 when the optical axis 31c of the optical imaging unit 31 and the optical axis 33b of the light source unit 33 are parallel to each other, but the present invention is not limited to this. In the present invention, for example, when the optical axis 31c of the optical imaging unit 31 and the optical axis 33b of the light source unit 33 are not parallel to each other, the control unit (optical imaging control unit) may be configured to calculate the body pressure of the subject 101 based on the optical image 70, taking into account the angle between the optical axis 31c of the optical imaging unit 31 and the optical axis 33b of the light source unit 33 (the tilt of the optical axis 31c of the optical imaging unit 31 with respect to the optical axis 33b of the light source unit 33).

[0135] Furthermore, in the above-described first to third embodiments, an example was shown in which the optical imaging control unit 32 (control unit) including a microcomputer is configured to superimpose the region display 80 (detector region display 81, X-ray irradiation field region display 84, and AEC region display 87 (irradiation field region)) on the optical image 70 and display it on the display operation unit 41 (display unit), but the present invention is not limited to this. In the present invention, a device control unit that controls X-ray imaging may be configured to superimpose the region displays (detector region display, X-ray irradiation field region display, and AEC region display) on the optical image. Furthermore, the optical image on which the region display is superimposed by the control unit (optical imaging control unit) may be output to the outside, and the region display may be superimposed on the optical image and displayed on a display unit located at a distance from the control unit. For example, a display unit may be provided on an imaging stand, and the optical image on which the region display is superimposed may be output and displayed on the display unit provided on the imaging stand. Alternatively, for example, an optical image with a superimposed area display may be displayed on a display unit provided in an apparatus control unit located outside the radiography room. The control unit may be configured with a personal computer, a processor, or circuitry. Each control process performed by the control unit may be performed by a combination of different hardware.

[0136] Furthermore, in the above-described first to third embodiments, an example of a configuration has been shown in which the optical imaging control unit 32 displays the detection unit region display 81, the X-ray irradiation field region display 84, and the AEC region display 87 (irradiation field region) as the region display 80 by superimposing them on the optical image 70, but the present invention is not limited to this. In the present invention, it is sufficient that the optical imaging control unit (control unit) is configured to display at least one of the detection unit region display, the X-ray irradiation field region display, and the AEC region display by superimposing them on the optical image as the region display.

[0137] Furthermore, in the above-described first to third embodiments, when the optical imaging control unit 32 superimposes and displays the region display 80 on the optical image 70 in the second mode, the region display 80 is deformed according to the body thickness of the subject 101 and superimposed based on the position on the body surface 101a of the subject 101 in real space. However, the present invention is not limited to this. In the present invention, when the optical imaging control unit (control unit) superimposes the region display in the second mode, it is not necessary to deform the shape according to the body thickness of the subject. However, if the shape of the region display is not deformed according to the body thickness of the subject when superimposing the region display in the second mode, it becomes difficult for the operator to visually recognize the accurate size of the X-ray detection unit in the optical image. Therefore, it is preferable that the optical imaging control unit (control unit) be configured to superimpose the region display deformed according to the body thickness of the subject on the body surface of the subject when superimposing and displaying the region display on the optical image in the second mode.

[0138] Furthermore, in the above-described first to third embodiments, an example of a configuration was shown in which the optical imaging control unit 32 displays the mode switching button 44 and the body thickness level selection button 45 on the display operation unit 41, but the present invention is not limited to this. In the present invention, the optical imaging control unit (control unit) does not have to display the mode switching button and the body thickness level selection button on the display operation unit (display unit). When the optical imaging control unit (control unit) does not display the mode switching button on the display operation unit (display unit), the optical imaging control unit may be configured to switch between the first mode and the second mode based on an operation input from the input receiving unit. When the optical imaging control unit (control unit) does not display the body thickness level selection button on the display operation unit (display unit), the optical imaging control unit may be configured to obtain the subject's body thickness based on an optical image, or to obtain the subject's body thickness based on the subject's body shape information.

[0139] Furthermore, in the above-described first to third embodiments, an example of a configuration in which the optical imaging control unit 32 switches between the first mode and the second mode based on input from the input receiving unit 43 has been described, but the present invention is not limited to this. In the present invention, the optical imaging control unit (control unit) may be configured to switch between the first mode and the second mode based on, for example, a gesture or vocalization by the operator. When switching between the first mode and the second mode based on the operator's gesture, the optical imaging control unit (control unit) may be configured to determine whether the operator has performed a predetermined gesture in an image (moving image) captured by the optical imaging unit 31. When switching between the first mode and the second mode based on the operator's vocalization, the X-ray imaging apparatus may be provided with a sound collection device (microphone) that detects the operator's vocalization, and the optical imaging control unit (control unit) may be configured to determine whether the operator has vocalized a predetermined keyword.

[0140] Furthermore, in the above first to third embodiments, when the optical imaging control unit 32 calculates the body thickness of the subject 101 based on the body type information 102 of the subject 101, the optical imaging control unit 32 calculates the body thickness of the subject 101 based on the height and weight of the subject 101, but the present invention is not limited to this. In the present invention, when calculating the body thickness of the subject based on the body type information of the subject, the optical imaging control unit (control unit) may be configured to calculate the body thickness of the subject based on the age and / or sex of the subject as well as the height and weight of the subject.

[0141] In addition, in the first to third embodiments, an example of a configuration in which the optical imaging control unit 32 displays the SID display area 90, the SOD display area 91, and the irradiation unit angle display area 92 on the display operation unit 41 has been shown, but the present invention is not limited to this. In the present invention, the optical imaging control unit (control unit) does not have to display the SID display area, the SOD display area, and the irradiation unit angle display area on the display operation unit (display unit).

[0142] Furthermore, in the above first to third embodiments, an example has been shown in which the imaging unit 30 including the optical imaging section 31 and the optical imaging control section 32 (control section) is disposed in the holding section 40 that holds the X-ray irradiation section 10, but the present invention is not limited to this. In the present invention, the optical imaging section and the control section may be disposed in positions spaced apart from each other. Furthermore, the optical imaging section may be disposed in a position different from the holding section, such as on the ceiling or wall of the imaging room. Furthermore, the imaging unit may be configured as a unit that is added to the X-ray imaging device.

[0143] Furthermore, in the above-described first to third embodiments, the position and angle of the X-ray irradiator 10 and the position of the X-ray detector 20 are acquired based on detection signals from the motion detector 50b in the moving mechanism 50 that moves the X-ray irradiator 10 and the X-ray detector 20. However, the present invention is not limited to this. In the present invention, a detector such as a magnetic sensor may be disposed in at least one of the X-ray detector and the X-ray irradiator to acquire the relative positional relationship between the X-ray detector and the X-ray irradiator. Furthermore, the area in the optical image where the X-ray detector is located may be detected by performing image processing on the optical image. For example, a marker element indicating the position of the X-ray detector may be disposed together with the X-ray detector, and the area in which the X-ray detector is located may be detected by detecting the marker element in the captured optical image.

[0144] Furthermore, in the first to third embodiments, the detection unit area display 81 includes a cross-shaped center display 82 and four area displays 83 indicating the four corners, and the X-ray radiation field area display 84 includes a rectangular frame area display 85 and a pair of dotted line displays 86. However, the present invention is not limited to this. In the present invention, the detection unit area display and the X-ray radiation field area display may be displayed in a manner different from that of the first to third embodiments. For example, either the detection unit area display or the X-ray radiation field area display may not include an indication indicating the center of the area. Furthermore, the detection unit area display may indicate the extent of the area using a rectangular frame line. The X-ray radiation field area display may not include a pair of dotted line displays, but may instead only show the rectangular frame line, or may indicate the extent of the rectangular area using only the four corners. At least one of the detection unit area display and the X-ray radiation field area display may be displayed transparently or flashing.

[0145] Furthermore, in the above-described first to third embodiments, the process in which the optical imaging control unit 32 (301, 402) switches the mode in which the region display 80 is superimposed on the optical image 70 from the first mode to the second mode, and the process in which the optical imaging control unit 301 switches the mode in which the region display 80 is superimposed on the optical image 70 from the second mode to the first mode, are described using a flow-driven flowchart in which the process is performed in order according to a processing flow. However, the present invention is not limited to this. For example, in the present invention, each of the above processes by the control unit may be performed by event-driven processing in which processing is performed on an event-by-event basis. In this case, the process may be performed completely event-driven, or may be a combination of event-driven and flow-driven processes.

[0146] Furthermore, although examples have been shown in which each of the above first to third embodiments is an individual embodiment, the first and second embodiments may be combined, or the second and third embodiments may be combined.

[0147] Aspects It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0148] (Item 1) An imaging system including an X-ray irradiation unit including an X-ray tube, an X-ray detection unit that detects X-rays irradiated from the X-ray irradiation unit and transmitted through a subject, an optical imaging unit that captures an optical image of the subject, a display unit that displays the optical image captured by the optical imaging unit, a control unit that controls display of the optical image on the display unit, and an input receiving unit that receives input from an operator, the control unit is configured to, when adjusting the position, based on input from an operator received by the input receiving unit, display the optical image on which at least one of a detection unit area display indicating the area in the optical image where the X-ray detection unit is located, an X-ray irradiation field area display indicating the area in the optical image to which X-rays are irradiated by the X-ray irradiator, and an X-ray irradiation field area display indicating the area in the optical image to which the X-rays irradiated by the X-ray irradiator are collected, superimposed, or to switch from a first mode in which the optical image is displayed without the area display superimposed on the optical image to a second mode in which the optical image is displayed on which the area display is superimposed, based on a position on the body surface of the subject in real space.

[0149] (Item 2) The X-ray imaging device according to Item 1, wherein the first mode is a mode in which, when adjusting the position of the subject, the optical image is displayed on the display unit superimposed with the area display based on the fixed position, and the second mode is a mode in which, when adjusting the position of the X-ray irradiation unit, the optical image is displayed on the display unit superimposed with the area display based on the position on the body surface of the subject in real space.

[0150] (Item 3) The X-ray imaging device according to Item 1 or 2, wherein the control unit is configured to control the display unit to display, when displaying the optical image in the second mode, the optical image in which the area display deformed according to a body thickness of the subject is superimposed based on a position on the body surface of the subject in real space.

[0151] (Item 4) An X-ray imaging device according to any one of items 1 to 3, further comprising a light source unit that irradiates visible light onto an irradiation field area that indicates an area to be irradiated with X-rays by the X-ray irradiation unit, wherein the input receiving unit is configured to receive an operation input to turn on the light source unit, and the control unit is configured to perform control to switch a mode for displaying the optical image from the first mode to the second mode based on the reception of the operation input to turn on the light source unit.

[0152] (Item 5) The X-ray imaging device according to Item 4, wherein the control unit is configured to control the display unit to superimpose the detection unit area display, the X-ray irradiation field area display, and the X-ray collection field area display on the optical image as the area display when displaying the optical image in the second mode.

[0153] (Item 6) The X-ray imaging device according to Item 5, wherein the control unit is configured to perform control such that a display mode of the region display in the first mode and a display mode of the region display in the second mode are made different from each other and the display modes are superimposed on the optical image and displayed on the display unit.

[0154] (Item 7) The X-ray imaging device according to any one of Items 3 to 6, wherein the control unit is configured to acquire a body thickness of the subject based on the optical image captured by the optical imaging unit, a selection operation of body thickness information of the subject by an operator, and body shape information of the subject, and to control the display unit to display, in the second mode, the optical image in which the region display deformed according to the acquired body thickness of the subject is superimposed based on a position on the body surface of the subject in real space.

[0155] (Item 8) The X-ray imaging device according to any one of Items 1 to 6, wherein the control unit is configured to control the display unit to superimpose the area display based on the fixed position on the optical image based on position information of the X-ray detection unit or standard body thickness information preset for each imaging region of the subject when superimposing the area display on the optical image in the first mode.

[0156] (Item 9) The X-ray imaging device according to any one of Items 1 to 7, further comprising a holding unit that holds the X-ray irradiation unit, wherein the optical imaging unit is provided on the holding unit together with the X-ray irradiation unit.

[0157] (Item 10) The X-ray imaging device according to any one of Items 1 to 9, wherein the control unit is configured to switch a mode in which the region display is superimposed on the optical image from the second mode to the first mode based on an input from an operator accepted by the input accepting unit or the optical image.

[0158] (Item 11) An imaging system including an X-ray irradiator including an X-ray tube, an X-ray detector that detects X-rays irradiated from the X-ray irradiator and transmitted through a subject, an optical imaging unit that captures an optical image of the subject, a display unit that displays the optical image captured by the optical imaging unit, a body surface position acquisition unit that acquires a body surface position of the subject in real space, a control unit that controls display of the optical image on the display unit, and an input receiving unit that receives input from an operator, the control unit is configured to, when adjusting the position, display the optical image on which at least one of a detection unit area display indicating the area in the optical image where the X-ray detection unit is located, an X-ray irradiation field area display indicating the area in the optical image to which X-rays are irradiated by the X-ray irradiator, and an X-ray irradiation field area display indicating the area in the optical image to which the X-rays irradiated by the X-ray irradiator are collected, superimposed, based on input from an operator received by the input receiving unit or the position of the body surface of the subject acquired by the body surface position acquisition unit, using a predetermined fixed position in real space as a reference; or to switch from a first mode in which the optical image is displayed without the area display superimposed on the optical image, to a second mode in which the optical image is displayed on which the area display is superimposed, based on a position on the body surface of the subject in real space as a reference.

[0159] REFERENCE SIGNS LIST 10 X-ray irradiation unit 11 X-ray tube 20 X-ray detection unit 31 Optical imaging unit 32, 301, 402 Optical imaging control unit (control unit) 33a Irradiation field area (area irradiated with X-rays) 40 Holding unit 41 Display operation unit (display unit) 43 Input reception unit 70 Optical image 80 Area display 81 Detection unit area display 84 X-ray irradiation field area display 87 AEC area display (X-ray collection field area display) 100, 300, 400 X-ray imaging device 101 Subject 101a Body surface of subject 102 Body shape information of subject 103 Position information of X-ray detection unit 104 Standard body thickness information 401 Optical imaging unit (body surface position acquisition unit)

Claims

1. An imaging apparatus comprising: an X-ray irradiation unit including an X-ray tube; an X-ray detection unit that detects X-rays irradiated from the X-ray irradiation unit and transmitted through an object; an optical imaging unit that captures an optical image of the object; a display unit that displays the optical image captured by the optical imaging unit; a control unit that controls the display of the optical image on the display unit; and an input receiving unit that receives input from an operator; The control unit is configured to control, when adjusting the position, to display the optical image on which at least one of a detection unit area display indicating the area in the optical image where the X-ray detection unit is located, an X-ray irradiation field area display indicating the area in the optical image where X-rays are irradiated by the X-ray irradiator, and an X-ray collection field area display indicating the area in the optical image where the X-rays irradiated by the X-ray irradiator are collected, based on a predetermined fixed position in real space, based on input from an operator received by the input receiving unit, or to switch from a first mode in which the optical image is displayed without superimposing the area display on the optical image and the area display is not displayed, to a second mode in which the optical image is displayed on which the optical image is superimposed with the area display based on a position on the body surface of the subject in real space.

2. The X-ray imaging device of claim 1, wherein the first mode is a mode in which, when adjusting the position of the subject, the optical image superimposed with the area display based on the fixed position is displayed on the display unit, and the second mode is a mode in which, when adjusting the position of the X-ray irradiation unit, the optical image superimposed with the area display based on the body surface of the subject in real space is displayed on the display unit.

3. The X-ray imaging device of claim 2, wherein the control unit is configured to control the display unit to display, when the optical image is displayed in the second mode, the optical image in which the area display deformed according to the body thickness of the subject is superimposed based on the position on the body surface of the subject in real space.

4. The X-ray imaging device of claim 3, further comprising a light source unit which irradiates visible light onto an irradiation field area which indicates an area to be irradiated with X-rays by the X-ray irradiation unit, wherein the input receiving unit is configured to receive an operation input for turning on the light source unit, and the control unit is configured to perform control for switching a mode for displaying the optical image from the first mode to the second mode based on the reception of the operation input for turning on the light source unit.

5. The X-ray imaging device of claim 4, wherein the control unit is configured to control the display unit to superimpose the detection unit area display, the X-ray irradiation field area display, and the X-ray collection field area display on the optical image as the area display when displaying the optical image in the second mode.

6. The X-ray imaging device of claim 5, wherein the control unit is configured to control the display mode of the area display in the first mode and the display mode of the area display in the second mode to be different from each other and to be superimposed on the optical image and displayed on the display unit.

7. The X-ray imaging device according to claim 3, wherein the control unit is configured to acquire the body thickness of the subject based on any one of the optical image captured by the optical imaging unit, a selection operation of the body thickness information of the subject by an operator, and body type information of the subject, and in the second mode, to control the display unit to display the optical image in which the area display deformed according to the acquired body thickness of the subject is superimposed based on the position on the body surface of the subject in real space.

8. The X-ray imaging device of claim 1, wherein the control unit is configured to control the display unit to superimpose the area display based on the fixed position on the optical image and display the area display on the display unit when the area display is superimposed on the optical image in the first mode, based on position information of the X-ray detection unit or standard body thickness information preset for each imaging part of the subject.

9. The X-ray imaging device according to claim 1, further comprising a holding section for holding said X-ray irradiation section, said optical imaging section being provided on said holding section together with said X-ray irradiation section.

10. The X-ray imaging device of claim 1, wherein the control unit is configured to switch the mode in which the area display is superimposed on the optical image from the second mode to the first mode based on the operator's input accepted by the input accepting unit or the optical image.

11. An imaging device comprising: an X-ray irradiation unit including an X-ray tube; an X-ray detection unit that detects X-rays irradiated from the X-ray irradiation unit and transmitted through a subject; an optical imaging unit that takes an optical image of the subject; a display unit that displays the optical image taken by the optical imaging unit; a body surface position acquisition unit that acquires the position of the body surface of the subject in real space; a control unit that controls the display of the optical image on the display unit; and an input acceptance unit that accepts input from an operator, the control unit is configured to control, when adjusting the position, to display the optical image on which at least one of a detection unit area display indicating an area in the optical image where the X-ray detection unit is located, an X-ray irradiation field area display indicating an area in the optical image where X-rays are irradiated by the X-ray irradiator, and an X-ray collection field area display indicating an area in the optical image where X-rays irradiated by the X-ray irradiator are collected, based on an input from an operator received by the input receiving unit or a position of the body surface of the subject acquired by the body surface position acquisition unit, with a predetermined fixed position in real space as a reference, or to switch from a first mode in which the optical image is displayed without superimposing the area display on the optical image and without displaying the area display, to a second mode in which the optical image is displayed on which the area display is superimposed, based on a position on the body surface of the subject in real space as a reference.