X-ray imaging system and x-ray image display method

Abstract

To provide an X-ray imaging system and an X-ray image display method that can easily identify an X-ray image corresponding to a maximum load timing, which is a timing at which the maximum load is being applied to one of legs.SOLUTION: An X-ray imaging system 100 includes: an X-ray irradiation unit 10 for applying an X-ray to a subject 101 who is performing a loaded action that applies a load on a leg; an X-ray detection unit 20 for detecting the X-ray; an optical imaging unit 30 for obtaining an optical image (load information) for identifying a state of the load applied to the leg during the loaded action of the subject 101; a display unit 60; and a control unit 50. The control unit 50 performs control to identifiably display, on the display unit 60, at least an X-ray image corresponding to a maximum load timing, which is a timing at which the maximum load is being applied to one of the legs during the loaded action of the subject 101, based on the optical image.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an X-ray imaging system and an X-ray image display method. [Background technology]

[0002] BACKGROUND ART Conventionally, an X-ray imaging system including an optical imaging unit is known (see, for example, Patent Document 1).

[0003] The above-mentioned Patent Document 1 describes a radiography system that captures radiographic images using X-rays. In this radiography system, moving images are captured using radiation while moving the joints under load in order to observe the movement of joints and bones during walking, etc. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-058570 Summary of the Invention [Problem to be solved by the invention]

[0005] Here, when an X-ray is taken of a subject while the subject is performing a weight-bearing movement, such as walking, as in the radiography system described in Patent Document 1, a doctor may make a diagnosis by observing the state of the bones or joints at the time when the greatest load is applied to one of the legs. However, when X-ray imaging is performed while the subject is performing a weight-bearing movement, it is difficult to identify the maximum load time, which is the time when the greatest load is applied to one of the legs, by visually checking only the X-ray image. Therefore, it is desirable to easily identify the X-ray image corresponding to the maximum load time, which is the time when the greatest load is applied to one of the legs.

[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 system and an X-ray image display method that can easily identify the X-ray image corresponding to the maximum load timing, which is the timing when the most load is applied to one of the legs. [Means for solving the problem]

[0007] An X-ray imaging system according to a first aspect of the present invention includes an X-ray irradiation unit that irradiates X-rays onto a subject performing a loading motion in which a load is applied to the legs; an X-ray detection unit that detects the X-rays irradiated from the X-ray irradiation unit and transmitted through the subject; a load information acquisition unit that acquires load information for identifying the state of load applied to the legs during the loading motion of the subject separately from the detection of X-rays by the X-ray detection unit; a display unit that displays an X-ray image generated by the detection of X-rays by the X-ray detection unit; and a control unit that controls the display unit to identifiably display, based on the load information acquired by the load information acquisition unit, an X-ray image corresponding to the maximum load timing, which is the timing when the greatest load is applied to at least one of the legs during the loading motion of the subject.

[0008] An X-ray image display method according to a second aspect of the present invention comprises the steps of irradiating X-rays to a subject performing a loading action in which a load is applied to the legs, detecting the X-rays that have passed through the subject, acquiring load information for identifying the state of the load applied to the legs during the loading action of the subject separately from the detection of the X-rays, and displaying an X-ray image generated by the detection of the X-rays, wherein the step of displaying the X-ray image includes a step of identifiably displaying an X-ray image corresponding to the maximum load timing, which is the timing when the greatest load is applied to at least one of the legs during the loading action of the subject, based on the acquired load information. [Effects of the Invention]

[0009] The X-ray imaging system according to the first aspect and the X-ray image display method according to the second aspect, as described above, distinguishably display, based on the acquired load information, an X-ray image corresponding to the maximum load timing, which is the timing when the greatest load is applied to at least one of the legs during the loading motion of the subject. As a result, since at least the X-ray image corresponding to the maximum load timing is distinguishably displayed, by visually recognizing the displayed X-ray image corresponding to the maximum load timing, it is possible to easily distinguish the X-ray image corresponding to the maximum load timing, which is the timing when the greatest load is applied to one of the legs. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram showing the overall configuration of an X-ray imaging system according to a first embodiment. [Figure 2] 1 is a block diagram showing the overall configuration of an X-ray imaging system according to a first embodiment. [Figure 3] 3 is a schematic diagram showing an example of displaying an X-ray image and an optical image on a display unit. FIG. [Figure 4] FIG. 10 is a diagram showing an example in which a plurality of X-ray images and an optical image are displayed side by side. [Figure 5] FIG. 4 is a flowchart for explaining the control process of the X-ray image display method by the X-ray imaging system of the first embodiment. [Figure 6] FIG. 10 is a block diagram showing the overall configuration of an X-ray imaging system according to a second embodiment. [Figure 7] FIG. 10 is a diagram for explaining detection of the position of the leg in the height direction according to the second embodiment. [Figure 8] FIG. 10 is a diagram showing a schematic example of a periodic change in the difference between the position of the toe of the right leg and the position of the toe of the left leg in the vertical direction of the optical image 80. [Figure 9] FIG. 10 is a schematic diagram for explaining the setting of the timing of X-ray irradiation. [Figure 10] 10A and 10B are diagrams showing examples of X-ray images displayed on a display unit corresponding to maximum load timings. [Figure 11] FIG. 10 is a flowchart for explaining the control process of an X-ray image display method by the X-ray imaging system of the second embodiment. [Figure 12] FIG. 10 is a schematic diagram showing the overall configuration of an X-ray imaging system according to a third embodiment. [Figure 13] FIG. 10 is a schematic diagram for explaining the setting of the timing of X-ray irradiation based on the detection result by the pressure sensor. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings.

[0012] [First embodiment] (X-ray imaging system configuration) The configuration of an X-ray imaging system 100 according to a first embodiment of the present invention will be described with reference to FIGS.

[0013] As shown in FIG. 1, the X-ray imaging system 100 is a system including a medical X-ray imaging device (so-called X-ray television device) that captures X-ray images 70 (see FIG. 3) as moving images by continuously irradiating X-rays, and is configured to X-ray an object 101 to be imaged. For example, before and after an artificial joint replacement surgery for a knee joint or the like, X-ray imaging is performed on the object 101 while the object 101 is walking, which is a weight-bearing movement that places weight on the leg. In this case, in the X-ray image 70 with the leg bent, bones of the knee joint are displayed overlapping each other, reducing visibility in the X-ray image 70. Therefore, a doctor makes a diagnosis using the X-ray image 70 taken when the leg is extended and weight is being applied. In the first embodiment, the X-ray imaging system 100 assists in identifying the X-ray image 70 corresponding to the maximum load timing, which is the timing when the greatest load is applied to one leg during the weight-bearing movement, from among a plurality of X-ray images 70 captured continuously as one frame of a moving image. When walking is performed as the weight-bearing movement, the walking motion may be performed by stepping on the spot, or by using a walking machine.

[0014] As shown in FIG. 2, the X-ray imaging system 100 includes an X-ray irradiation unit 10, an X-ray detection unit 20, an optical imaging unit 30, a moving mechanism 40, a control unit 50, and a display unit 60. In the X-ray imaging system 100, X-rays irradiated from the X-ray irradiation unit 10 are detected by the X-ray detection unit 20, thereby performing X-ray imaging of a subject 101. In the X-ray imaging system 100, an optical image 80 (see FIG. 3) capturing an external view of the subject 101 is also captured by the optical imaging unit 30. As shown in FIG. 1, in the X-ray imaging system 100, for example, the X-ray irradiation unit 10, the X-ray detection unit 20, the optical imaging unit 30, and the moving mechanism 40 are installed in an imaging room 110, and the control unit 50 and the display unit 60 are installed outside the imaging room 110. Note that the control unit 50 and the display unit 60 may be installed inside the imaging room 110. The optical imaging unit 30 is an example of a "load information acquisition unit" in the claims. The optical image 80 is an example of "load information" in the claims.

[0015] The X-ray irradiator 10 irradiates X-rays onto the subject 101 while the subject 101 is performing a loading operation. The X-ray irradiator 10 includes an X-ray tube 11 and a collimator unit 12. The X-ray irradiator 10 is configured to irradiate X-rays from the X-ray tube 11 onto the subject 101. The X-ray tube 11 is configured to irradiate X-rays when a predetermined voltage is applied. The collimator unit 12 has a plurality of shielding plates (collimator leaves) whose positions can be adjusted. The collimator unit 12 is configured to define (adjust) the irradiation field of the X-rays irradiated from the X-ray tube 11 by shielding part 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.

[0016] The X-ray detection unit 20 is configured to detect X-rays that are irradiated from the X-ray irradiation unit 10 and have passed through the subject 101. For example, the X-ray detection unit 20 is movably disposed on a bed 21 of an X-ray television device. The X-ray detection unit 20 includes a flat panel detector (FPD). The X-ray detection unit 20 outputs a signal based on the detected X-rays to the control unit 50.

[0017] The X-ray irradiator 10 is movably held within the imaging room 110 by a moving mechanism 40. 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. The moving mechanism 40 is configured to movably hold the X-ray irradiator 10. The moving mechanism 40 includes a support unit 41 that supports the X-ray irradiator 10. The moving mechanism 40 moves the X-ray irradiator 10 and the bed 21 on which the X-ray detection unit 20 is arranged, while they face each other. The moving mechanism 40, for example, rotates the bed 21 and the support unit 41 integrally to an upright position. In addition, the support unit 41 changes the distance between the X-ray irradiator 10 and the bed 21 on which the X-ray detection unit 20 is arranged. In the first embodiment, the bed 21 is arranged in an upright position to image the subject 101 who is walking from the horizontal X direction. That is, the X-ray irradiator 10 and the X-ray detector 20 are arranged facing each other along the horizontal direction (X direction). The movement mechanism 40 has, for example, a motor as a drive source.

[0018] The optical imaging unit 30 captures an optical image 80 (see FIG. 3 ) of the subject 101 while the subject 101 is performing a loading motion. The optical imaging unit 30 acquires the optical image 80 as load information for identifying the state of the load on the legs of the subject 101 during the loading motion, separately from the detection of X-rays by the X-ray detection unit 20. In the first embodiment, the optical imaging unit 30 is disposed on the outer surface of the collimator unit 12. The optical imaging unit 30 is disposed facing 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 30 captures the optical image 80 of the subject 101 from the X-ray irradiator 10 side. The optical imaging unit 30 is, for example, an optical camera. The optical imaging unit 30 includes an imaging element such as a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor. The optical imaging unit 30 transmits and receives signals to and from the control unit 50 via a wireless or wired connection. The optical imaging unit 30 outputs a signal detected by the imaging element to the control unit 50. The optical imaging unit 30 is configured to capture an optical image 80 by the control unit 50 in synchronization with the detection of X-rays by the X-ray detection unit 20, separately from the detection of X-rays by the X-ray detection unit 20.

[0019] The control unit 50 controls X-ray photography by the X-ray irradiation unit 10 and the X-ray detection unit 20, and controls the capture of the optical image 80 by the optical imaging unit 30. Specifically, the control unit 50 includes a CPU (Central Processing Unit). The control unit 50 controls X-ray photography and the capture of the optical image 80 based on parameters and various programs that are set in advance and stored in a storage device. The control unit 50 also controls the display of the X-ray image 70 and the optical image 80 on the display unit 60.

[0020] 3, the display unit 60 displays an X-ray image 70 generated by the control unit 50 based on the detection of X-rays by the X-ray detection unit 20. The display unit 60 also displays an optical image 80 generated by the control unit 50 based on the imaging by the optical imaging unit 30. The display unit 60 includes, for example, a liquid crystal display.

[0021] (Control of display of X-ray and optical images) 4, in the first embodiment, the control unit 50 is configured to perform control to display an X-ray image 70 corresponding to the maximum load timing in an identifiable manner on the display unit 60, based on an optical image 80 captured (acquired) by the optical imaging unit 30. In the first embodiment, an X-ray image 70 capturing the knee joint of the right leg, which is one of the legs, and an optical image 80 covering the area from the knee joint to the toes are acquired and displayed on the display unit 60.

[0022] Specifically, in the first embodiment, the control unit 50 generates a plurality of X-ray images 70 by continuously irradiating X-rays onto the subject 101 performing a loading motion. The control unit 50 causes the X-ray irradiator 10 to continuously irradiate X-rays at a predetermined irradiation rate, and acquires a detection signal that detects the X-rays irradiated at the predetermined irradiation rate from the X-ray detector 20. The predetermined irradiation rate is, for example, 10 times per second. The control unit 50 generates a plurality of X-ray images 70 based on the X-ray detection signal from the X-ray detector 20. Each of the plurality of X-ray images 70 is, for example, an image for each frame of a moving image.

[0023] The control unit 50 also acquires optical images 80 as moving images captured by the optical imaging unit 30 at a frame rate at least equal to the X-ray irradiation rate. In the first embodiment, the control unit 50 sets the imaging rate (period) of the optical imaging unit 30 to be equal to the frame rate of the X-ray irradiation rate. The control unit 50 captures optical images 80 as moving images whose frame rate is equal to the X-ray irradiation rate at which the multiple X-ray images 70 were acquired and whose timing is synchronized. The optical images 80 as moving images include multiple optical images 80 as still images. The control unit 50 generates multiple optical images 80 by successively optically capturing the appearance of the subject 101 based on a signal from the optical imaging unit 30. The control unit 50 synchronizes the operation of the X-ray irradiator 10 and the X-ray detection unit 20 with the operation of the optical imaging unit 30, thereby synchronizing the timing at which each of the multiple X-ray images 70 is captured as one frame of the moving image with the timing at which each of the multiple optical images 80 is captured as one frame of the moving image.

[0024] In the first embodiment, in order to display the X-ray image 70 corresponding to the maximum load timing, the control unit 50 captures the X-ray image 70 and the optical image 80 as a moving image over a period corresponding to one cycle of walking. For example, the control unit 50 captures the X-ray image 70 and the optical image 80 as a moving image over a period corresponding to one cycle of walking, during which the subject 101 performs a series of movements, from lifting one leg in walking to applying a load to one leg and lifting the other leg, and then lifting the one leg again. Therefore, the multiple X-ray images 70 and the multiple optical images 80 generated by the control unit 50 include one X-ray image 70 and one optical image 80 corresponding to the maximum load timing, which is the timing when the greatest load is applied to one leg in walking.

[0025] As shown in FIG. 4 , in the first embodiment, the control unit 50 displays the generated multiple X-ray images 70 and multiple optical images 80 side by side on the display unit 60. That is, the multiple X-ray images 70 include the X-ray image 70 corresponding to the maximum load timing, and the multiple optical images 80 include the optical image 80 corresponding to the maximum load timing. Therefore, in the first embodiment, the control unit 50 displays the X-ray image 70 corresponding to the maximum load timing and the optical image 80 corresponding to the maximum load timing side by side on the display unit 60, thereby displaying the X-ray image 70 corresponding to the maximum load timing in association with the optical image 80 corresponding to the maximum load timing on the display unit 60. A doctor visually recognizes the multiple optical images 80 displayed on the display unit 60 frame by frame, and determines which of the multiple optical images 80 corresponds to the maximum load timing based on the appearance of the leg. For example, the doctor determines the optical image 80 corresponding to the maximum load timing by comparing it with optical images 80 taken before and after the maximum load timing and by referring to the position and angle of the leg. This allows the doctor to identify the X-ray image 70 corresponding to the maximum load timing from among the multiple X-ray images 70. That is, the control unit 50 controls the display unit 60 to display the multiple X-ray images 70 and the optical image 80 acquired (captured) in synchronization with the timing of X-ray detection by the X-ray detection unit 20 side by side, thereby displaying the X-ray image 70 corresponding to the maximum load timing from among the multiple X-ray images 70 in an identifiable manner.

[0026] For example, the control unit 50 displays an X-ray image 70 and an optical image 80 acquired at the same timing side by side on the display unit 60, and also displays pairs of the X-ray image 70 and the optical image 80 acquired at the same timing side by side vertically in chronological order, frame by frame. The X-ray image 70 and the optical image 80 displayed on the display unit 60 may be of the same size or may be of different sizes.

[0027] In the first embodiment, the optical image 80 corresponding to the maximum load timing is identified by a doctor viewing the display unit 60 based on the plurality of optical images 80 displayed on the display unit 60. Then, the X-ray image 70 displayed in association with (side by side with) the optical image 80 corresponding to the maximum load timing is identified as the X-ray image 70 corresponding to the maximum load timing.

[0028] (X-ray image display method according to the first embodiment) Next, the control process of the X-ray image display method by the X-ray imaging system 100 of the first embodiment will be described with reference to Fig. 5. The control process of the image display method by steps 401 to 406 is executed by the control unit 50.

[0029] First, in step 401, the frame rates of the X-ray image 70 and the optical image 80 are set. That is, the rate at which X-rays are irradiated by the X-ray irradiator 10 and the rate at which X-ray detection signals are acquired by the X-ray detector 20 are synchronized with the rate at which the optical image 80 is acquired by the optical imaging unit 30.

[0030] Next, in step 402, X-rays are continuously irradiated at a set irradiation rate onto the subject 101 while the subject 101 is walking as a load-bearing movement. Next, in step 403, the X-ray detection unit 20 detects the X-rays that have passed through the subject 101. Then, in step 404, a signal indicating the detection result of the detected X-rays is acquired, thereby generating and acquiring a plurality of X-ray images 70.

[0031] Next, in step 405, separately from the detection of X-rays, an optical image 80 is acquired as load information for identifying the state of the load applied to the legs during walking of the subject 101. In the first embodiment, the optical image capturing unit 30 captures the optical image 80 as a moving image at a frame rate synchronized with the timing of the X-ray irradiation in step 402. Based on the signal from the optical image capturing unit 30, the optical image 80 as a moving image (optical images 80 as a plurality of still images) is generated.

[0032] Next, in step 406, the X-ray image 70 generated by the detection of X-rays is displayed on the display unit 60. In the first embodiment, in step 406, based on the acquired optical image 80, the X-ray image 70 corresponding to the timing of maximum load in the walking movement of the subject 101 is displayed in a identifiable manner on the display unit 60. Specifically, the multiple X-ray images 70 and the optical image 80 acquired in synchronization with the timing of X-ray detection by the X-ray detection unit 20 are displayed side by side on the display unit 60, so that the X-ray image 70 corresponding to the timing of maximum load is displayed in a identifiable manner from among the multiple X-ray images 70.

[0033] It should be noted that either the control process for generating the X-ray image 70 in step 404 or the control process for acquiring (generating) the optical image 80 in step 405 may be executed first.

[0034] (Effects of the first embodiment) In the first embodiment, the following effects can be obtained.

[0035] In the first embodiment, as described above, based on the acquired optical image 80 (load information), at least the X-ray image 70 corresponding to the maximum load timing, which is the timing when the greatest load is applied to one of the legs during the walking movement (load-applying movement) of the subject 101, is displayed in an identifiable manner. As a result, since at least the X-ray image 70 corresponding to the maximum load timing is displayed in an identifiable manner, by visually recognizing the displayed X-ray image 70 corresponding to the maximum load timing, it is possible to easily identify the X-ray image 70 corresponding to the maximum load timing, which is the timing when the greatest load is applied to one of the legs.

[0036] Furthermore, the optical imaging unit 30 (load information acquisition unit) acquires an optical image 80 (load information) for identifying the state of the load on the legs during the loading motion of the subject 101, separately from the detection of X-rays by the X-ray detection unit 20. This reduces the burden on the control unit 50 required for control processing compared to when image processing is performed to extract bones from the X-ray image 70 and processing is performed to identify the state of the load on the legs from the position and shape of the extracted bones.

[0037] Furthermore, in the first embodiment, the following additional effects can be obtained by configuring as follows.

[0038] That is, in the first embodiment, as described above, the control unit 50 controls the display unit 60 to identifiably display the X-ray image 70 corresponding to the maximum load timing, in which at least one of the ankle joint, knee joint, and hip joint of one leg is photographed, based on the optical image 80 (load information) acquired by the optical imaging unit 30 (load information acquisition unit). With this configuration, when observing the state of the joints during loading operations, by checking the X-ray image 70 in which at least one of the ankle joint, knee joint, and hip joint is photographed, it is possible to effectively and easily identify the X-ray image 70 corresponding to the maximum load timing, which is the timing when the most load is applied to one of the legs.

[0039] Furthermore, in the first embodiment, the X-ray imaging system 100 includes an optical imaging unit 30 that captures an optical image 80 of the subject 101 while the subject 101 is performing a load-bearing motion. Here, the optical image 80 captured by the optical imaging unit 30 captures the external appearance of the subject 101, so it is possible to more easily identify the state of the load applied to the legs during the load-bearing motion. Therefore, by identifying the X-ray image 70 corresponding to the timing of maximum load based on the optical image 80, it is possible to more easily identify the X-ray image 70 corresponding to the timing of maximum load.

[0040] Furthermore, in the first embodiment, the X-ray imaging system 100 includes an optical imaging unit 30 that captures an optical image 80 of the subject 101 while the subject 101 is performing a loading motion. The optical imaging unit 30 is disposed in at least one of the support unit 41 that supports the X-ray irradiator 10 and the collimator unit 12 that defines the irradiation field of X-rays irradiated from the X-ray irradiator 10. With this configuration, the optical imaging unit 30 is disposed in the collimator unit 12 that defines at least one of the support unit 41 that supports the X-ray irradiator 10 and the collimator unit 12, so that the direction in which X-rays are irradiated by the X-ray irradiator 10 and the direction in which the optical imaging unit 30 captures the optical image 80 can be aligned. Therefore, by visually comparing the optical image 80 and the X-ray image 70, it is possible to more easily identify the X-ray image 70 corresponding to the maximum loading timing.

[0041] Furthermore, in the first embodiment, the X-ray imaging system 100 includes an optical imaging unit 30 that captures an optical image 80 of the subject 101 while the subject 101 is performing a loading motion. The control unit 50 displays an X-ray image 70 corresponding to the maximum load timing in association with the optical image 80 captured by the optical imaging unit 30. With this configuration, since the X-ray image 70 corresponding to the maximum load timing is displayed in association with the captured optical image 80, it is possible to easily recognize whether the X-ray image 70 associated with the optical image 80 is the X-ray image 70 corresponding to the maximum load timing by visually recognizing the optical image 80. As a result, it is possible to more easily identify the X-ray image 70 corresponding to the maximum load timing.

[0042] Furthermore, in the first embodiment, the control unit 50 displays the X-ray image 70 corresponding to the timing of maximum load and the optical image 80 corresponding to the timing of maximum load side by side on the display unit 60. With this configuration, the X-ray image 70 and the optical image 80 displayed side by side on the display unit 60 can be easily compared, and therefore, by visually recognizing the optical image 80 corresponding to the timing of maximum load, it is possible to more easily identify the X-ray image 70 corresponding to the timing of maximum load.

[0043] Furthermore, in the first embodiment, the control unit 50 controls the display unit 60 to identifiably display, from among a plurality of X-ray images 70 acquired by continuously irradiating X-rays on the subject 101 performing a loading motion, an X-ray image 70 corresponding to the timing of maximum loading. With this configuration, by visually recognizing the plurality of X-ray images 70 acquired by continuously irradiating X-rays, it is possible to confirm the movements of the joints and bones of the subject 101 that change with the loading motion, and also to easily identify the X-ray image 70 corresponding to the timing of maximum loading in the loading motion.

[0044] Furthermore, in the first embodiment, the control unit 50 controls the display unit 60 to display, side by side, a plurality of X-ray images 70 including the X-ray image 70 corresponding to the timing of maximum load and an optical image 80 acquired in synchronization with the timing of X-ray detection by the X-ray detection unit 20, thereby enabling the X-ray image 70 corresponding to the timing of maximum load to be identified from among the plurality of X-ray images 70. With this configuration, the plurality of X-ray images 70 acquired by continuously irradiating X-rays and the optical image 80 acquired in synchronization with the timing are displayed side by side, so that the X-ray image 70 corresponding to the timing of maximum load can be easily identified from among the plurality of X-ray images 70 by identifying the optical image 80 in which the appearance of the subject 101 is captured.

[0045] [Second embodiment] The configuration of an X-ray imaging system 200 according to a second embodiment will be described with reference to Figures 6 to 10. Unlike the first embodiment in which the X-ray image 70 corresponding to the maximum load timing is identified by a doctor based on the displayed optical image 80, in this second embodiment, the X-ray image 70 corresponding to the maximum load timing is automatically identified by control processing by the control unit 250. Note that in the figures, components similar to those in the first embodiment are denoted by the same reference numerals and will not be described again.

[0046] (Configuration of X-ray imaging system according to second embodiment) 6, an X-ray imaging system 200 according to the second embodiment includes an X-ray irradiation unit 10, an X-ray detection unit 20, an optical imaging unit 30, a movement mechanism 40, a control unit 250, and a display unit 60. Similar to the control unit 50 of the first embodiment, the control unit 250 controls X-ray imaging by the X-ray irradiation unit 10 and the X-ray detection unit 20, and controls the capture of an optical image 80 by the optical imaging unit 30. The hardware configuration of the control unit 250 is similar to that of the control unit 50 of the first embodiment.

[0047] In the second embodiment, the control unit 250 acquires the maximum load timing based on the optical image 80 acquired by the optical imaging unit 30. Specifically, the control unit 250 acquires the maximum load timing based on the position in the height direction of the other leg of the subject 101 based on the optical image 80 acquired as load information. Then, the control unit 250 performs control to distinguishably display the X-ray image 70 corresponding to the maximum load timing on the display unit 60 based on the acquired maximum load timing.

[0048] 7, before X-ray imaging is performed, the control unit 250 acquires an optical image 80 of the subject 101 who is walking. For example, before X-ray imaging is performed, the control unit 250 acquires the optical image 80 as a moving image by capturing an image of the subject 101 who is repeatedly walking using the optical imaging unit 30. Then, the control unit 250 acquires the optical image 80 acquired as a moving image as a plurality of optical images 80 as still images for each frame, and acquires the position of the other leg in the height direction in each of the plurality of optical images 80.

[0049] When acquiring an X-ray image 70 of the knee joint of the right leg, which is one of the legs, the control unit 250 acquires the position in the height direction of the left leg, which is the other leg. The control unit 250 acquires the position in the height direction of the left leg in the vertical direction by performing image processing such as pattern matching on each of the acquired optical images 80. For example, the control unit 250 detects a distance D1, which is the difference between the position of the toe of the right leg and the position of the toe of the left leg in the up-down direction of the optical image 80, as the position in the height direction of the left leg.

[0050] As shown in Fig. 8, the value of the distance D1 periodically fluctuates during multiple walking cycles. The timing at which the distance D1 is maximum during one walking cycle corresponds to the maximum load timing at which the right leg, one of the legs, is subjected to the greatest load during one walking cycle. Before performing X-ray imaging, the control unit 250 acquires optical images 80 as moving images over multiple walking cycles. The control unit 250 then performs a process of detecting the distance D1 for each of the multiple optical images 80 acquired as still images for each frame of the moving images, thereby acquiring the change in the distance D1 during the walking cycles of the subject 101.

[0051] As shown in FIG. 9 , in the second embodiment, the control unit 250 is configured to acquire a maximum load timing based on the value of the distance D1 and a judgment threshold when performing X-ray imaging, and to cause the X-ray irradiator 10 to irradiate X-rays at the acquired maximum load timing. The control unit 250 sets a judgment threshold for determining the maximum load timing based on periodic values ​​of the distance D1 in the walking movement of the subject 101 over multiple cycles acquired before X-ray imaging. For example, the judgment threshold is acquired based on the maximum value of the distance D1 for each of the multiple cycles acquired before X-ray imaging. The judgment threshold is set, for example, as a value obtained by multiplying the average value of the maximum values ​​of the distance D1 for each of the multiple cycles by a predetermined ratio. The judgment threshold may also be a predetermined value.

[0052] When performing X-ray imaging, the control unit 250 acquires the optical image 80 captured by the optical imaging unit 30 as a real-time moving image, and acquires the timing at which the magnitude of the distance D1 detected in the acquired optical image 80 exceeds a set determination threshold as the maximum load timing. When performing X-ray imaging, the control unit 250 is configured to cause the X-ray irradiator 10 to irradiate X-rays at the timing at which the value of the distance D1 detected in the optical image 80 acquired in real time while performing a loading operation exceeds the determination threshold. In this way, in the second embodiment, the timing of X-ray irradiation is controlled based on the optical image 80, so that the X-ray image 70 corresponding to the maximum load timing is captured.

[0053] 10, the control unit 250 displays one X-ray image 70 generated by detecting the X-rays irradiated at the maximum load timing on the display unit 60 as the X-ray image 70 corresponding to the maximum load timing. That is, unlike the first embodiment in which a plurality of X-ray images 70 are displayed and one X-ray image 70 corresponding to the maximum load timing is identifiable, in the second embodiment, only one X-ray image 70 corresponding to the maximum load timing is displayed on the display unit 60, thereby identifiable display of the X-ray image 70 corresponding to the maximum load timing. Note that other configurations of the second embodiment are similar to those of the first embodiment.

[0054] (X-ray image display method according to the second embodiment) Next, the control process of the X-ray image display method by the X-ray imaging system 200 of the second embodiment will be described with reference to Fig. 11. The control process of the X-ray image display method by steps 501 to 507 is executed by the control unit 250.

[0055] First, a judgment threshold is set in step 501. For example, from optical images 80 acquired over multiple periods during walking, a distance D1, which is the difference between the position of the toe of the right leg and the position of the toe of the left leg in the up-down direction of optical images 80, is acquired as a value representing the position in the height direction of the other leg (left leg) of subject 101. Then, a judgment threshold is set for determining the timing of maximum load in one period from the periodic change in the value of distance D1.

[0056] Next, in step 502, optical images 80 are acquired for X-ray imaging. In order to irradiate X-rays at the timing of maximum load, optical images 80 of the subject 101 while he is walking are acquired as a moving image. The optical images 80 are acquired continuously at timings corresponding to a predetermined frame rate so as to form a moving image at a predetermined frame rate.

[0057] Then, in step 503, distance D1 is acquired from the optical image 80 acquired in step 502, and it is determined whether the acquired distance D1 is greater than the determination threshold set in step 501. If it is determined that distance D1 is greater than the determination threshold, the process proceeds to step 504. If it is determined that distance D1 is equal to or less than the determination threshold, the process returns to step 502, and a new frame of optical image 80 is acquired. Note that the control process in step 503 is executed every time an optical image 80, which is a still image as one frame of a moving image, is acquired at a predetermined frame rate in step 502.

[0058] In step 504, X-rays are irradiated. That is, when the value of the distance D1 detected in the acquired optical image 80 is greater than a predetermined judgment threshold, it is determined that the maximum load timing has been detected. Then, X-rays are irradiated at the maximum load timing.

[0059] Next, in step 505, X-rays irradiated at the maximum load timing are detected. Then, in step 506, an X-ray image 70 corresponding to the maximum load timing is generated based on the detected X-rays. Then, in step 507, the generated X-ray image 70 corresponding to the maximum load timing is displayed on the display unit 60 in an identifiable manner. In step 507, for example, only one X-ray image 70 corresponding to the maximum load timing is displayed on the display unit 60, thereby identifiable displaying the X-ray image 70 corresponding to the maximum load timing.

[0060] (Effects of the second embodiment) In the second embodiment, the following effects can be obtained.

[0061] In the second embodiment, the control unit 250 acquires the maximum load timing based on the optical image 80 (load information) acquired by the optical imaging unit 30 (load information acquisition unit). Furthermore, the control unit 250 performs control to identifiably display the X-ray image 70 corresponding to the maximum load timing on the display unit 60 based on the acquired maximum load timing. With this configuration, the maximum load timing is automatically acquired by the control unit 250, and therefore the X-ray image 70 corresponding to the maximum load timing can be automatically identified by the control process of the control unit 250. Therefore, it is possible to reduce the effort required to identify the X-ray image 70 corresponding to the maximum load timing.

[0062] Furthermore, in the second embodiment, the X-ray imaging system 200 includes an optical imaging unit 30 that captures an optical image 80 of the subject 101 while the subject 101 is performing a load-bearing motion. The control unit 250 acquires the maximum load timing based on the optical image 80 acquired as load information, based on the position of the other leg of the subject 101 in the height direction, which is at least one of the position of the other leg of the subject 101 in the height direction and the tilt of the body axis of the subject 101. With this configuration, the maximum load timing can be automatically and easily acquired by determining the position of the other leg of the subject 101 in the height direction in the optical image 80. Therefore, the processing load of the control process for acquiring the maximum load timing can be reduced.

[0063] Furthermore, in the second embodiment, the control unit 250 is configured to cause the X-ray irradiator 10 to irradiate X-rays at the acquired maximum load timing. With this configuration, it is possible to prevent the dose of X-rays irradiated to the subject 101 from increasing compared to when a plurality of X-ray images 70 are acquired by continuously irradiating X-rays, and it is also possible to easily acquire the X-ray image 70 corresponding to the maximum load timing.

[0064] Other effects of the second embodiment are similar to those of the first embodiment.

[0065] [Third embodiment] The configuration of an X-ray imaging system 300 according to the third embodiment will be described with reference to Figures 12 and 13. Unlike the first and second embodiments in which an optical imaging unit 30 that captures an optical image 80 is provided, this third embodiment is provided with a pressure sensor 330. Note that in the figures, parts with the same configuration as those in the first and second embodiments are denoted by the same reference numerals and will not be described again. The pressure sensor 330 is an example of a "load information acquisition unit" in the claims.

[0066] (Configuration of X-ray imaging system according to the third embodiment) 12, an X-ray imaging system 300 according to the third embodiment includes an X-ray irradiator 10, an X-ray detector 20, a pressure sensor 330, a moving mechanism 40, a controller 350, and a display 60. The controller 350 controls X-ray imaging by the X-ray irradiator 10 and the X-ray detector 20, similar to the controller 50 of the first embodiment and the controller 250 of the second embodiment. In the third embodiment, the controller 350 controls pressure detection by the pressure sensor 330 and performs analysis based on the detection results by the pressure sensor 330. The hardware configuration of the controller 350 is the same as in the first and second embodiments.

[0067] The pressure sensor 330 detects pressure applied by the legs of the subject 101 while the subject 101 is walking as a weight-bearing movement. The pressure sensor 330 is a sheet-like sensor placed on the floor of the imaging room 110 so as to be stepped on by the subject 101 while walking. The pressure sensor 330 includes, for example, a strain gauge or a capacitance sensor. The pressure sensor 330 detects the pressure applied by the legs of the subject 101 by being stepped on by the subject 101 while walking, and outputs a signal indicating the detection result to the control unit 350. That is, the pressure sensor 330 acquires the detection result of the pressure applied by the legs as load information for identifying the state of the load applied to the legs during walking as a weight-bearing movement of the subject 101, separately from the detection of X-rays by the X-ray detection unit 20.

[0068] 13, in the third embodiment, the control unit 350 acquires the detection result by the pressure sensor 330 as load information. The control unit 350 then acquires the maximum load timing by detecting the magnitude of the pressure applied by one of the legs based on the acquired detection result. The control unit 350 is configured to cause the X-ray irradiator 10 to irradiate X-rays at the acquired maximum load timing.

[0069] As in the second embodiment, the control unit 350 sets a judgment threshold for detecting the maximum load timing before performing X-ray imaging. Then, based on the detection result from the pressure sensor 330, the control unit 350 judges the timing at which the magnitude of the pressure applied by one leg is greater than the set judgment threshold as the maximum load timing, and at the time determined to be the maximum load timing, irradiates X-rays to obtain the X-ray image 70 corresponding to the maximum load timing.

[0070] Specifically, similar to the second embodiment, the control unit 350 acquires periodic values ​​of the magnitude of pressure applied by one leg based on the detection results from the pressure sensor 330 over multiple periods of walking before performing X-ray imaging. During walking, the magnitude of pressure applied by one leg changes periodically and reaches a maximum value at the timing of maximum load. Similar to the distance D1 in the second embodiment, the control unit 350 sets a judgment threshold for determining the timing of maximum load based on the periodic change in the magnitude of pressure applied by one leg acquired before X-ray imaging. Similarly to the second embodiment, when performing X-ray imaging, the control unit 350 continuously acquires detection results from the pressure sensor 330 and, each time a detection result is acquired, determines whether the magnitude of pressure applied by one leg is greater than the set judgment threshold. The control unit 350 determines that the timing of maximum load has been detected at the timing at which it is determined that the magnitude of pressure applied by one leg is greater than the set judgment threshold, and executes control processing for X-ray imaging by the X-ray irradiator 10 and the X-ray detector 20. Then, similarly to the second embodiment, the control unit 350 controls the display unit 60 to display the X-ray image 70 corresponding to the maximum load timing acquired based on the detection result of the pressure sensor 330. Other configurations of the third embodiment are similar to those of the second embodiment.

[0071] (Effects of the third embodiment) In the third embodiment, the following effects can be obtained.

[0072] In the third embodiment, the X-ray imaging system 300 includes a pressure sensor 330 that detects the pressure applied by the legs of the subject 101 while the subject 101 is performing a loading motion. With this configuration, it is possible to easily and directly identify the state of the load applied to the legs during the loading motion based on the detection result by the pressure sensor 330. Therefore, it is possible to more easily identify the X-ray image 70 corresponding to the maximum load timing, which is the timing when the greatest load is applied to one of the legs, based on the detection result by the pressure sensor 330.

[0073] Furthermore, in the third embodiment, the X-ray imaging system 300 includes a pressure sensor 330 that detects the pressure applied by the legs of the subject 101 while the subject 101 is performing a loading motion. The control unit 350 acquires the maximum load timing based on the magnitude of the pressure applied by one leg, which is at least one of the magnitude of the pressure applied by one leg and the comparison between the pressure applied by one leg and the pressure applied by the other leg, based on the detection result by the pressure sensor 330 acquired as load information. With this configuration, the maximum load timing can be automatically and easily acquired by determining the magnitude of the pressure applied by one leg. Therefore, the processing load of the control process for acquiring the maximum load timing can be reduced.

[0074] Other effects of the third embodiment are similar to those of the first and second embodiments.

[0075] [Variations] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims rather than the above description of the embodiments, and further includes all modifications (variations) within the meaning and scope of the claims.

[0076] For example, in the first to third embodiments, an example has been shown in which X-rays are irradiated onto the subject 101 who is walking as a load-bearing movement that applies a load to the legs, but the present invention is not limited to this. In the present invention, the load-bearing movement that applies a load to the legs may be an ascent or descent movement such as going up and down a step, or a bending and stretching movement in a standing position.

[0077] Furthermore, in the above first to third embodiments, an example was shown in which the X-ray image 70 corresponding to the maximum load timing when the knee joint was photographed was displayed in an identifiable manner, but the present invention is not limited to this. In the present invention, the display unit may be configured to identifiably display X-ray images corresponding to the maximum load timing when at least one of the ankle joint, knee joint, and hip joint is photographed. Furthermore, it is not limited to the joints of the legs, and X-ray images corresponding to the maximum load timing including the pelvis or spine may also be displayed in an identifiable manner.

[0078] In the first and second embodiments, an example is shown in which an X-ray image 70 of a knee joint and an optical image 80 including the area from the knee joint to the toes are acquired, but the present invention is not limited to this. In the present invention, the imaging ranges of the X-ray image and the optical image may be the same or different. For example, when X-raying a knee joint, an optical image of the entire body of the subject may be acquired.

[0079] In the first and second embodiments, the optical imaging unit 30 is provided to acquire an optical image 80 as load information for identifying the state of the load on the legs. In the third embodiment, the pressure sensor 330 is provided to acquire the detection result of the pressure applied by the legs as load information for identifying the state of the load on the legs. However, the present invention is not limited to this. In the present invention, other detection sensors that detect the subject's movement may be provided as the load information acquisition unit. For example, a gyro sensor attached to the subject's body may be provided as the load information acquisition unit. Furthermore, the state of the subject's load movement may be identified using a non-contact capacitance sensor, a magnetic sensor, or a photoelectric sensor. Furthermore, load information may be acquired by combining multiple types of sensors. For example, load information may be acquired by combining an optical imaging unit and a pressure sensor. That is, each of the multiple types of load information may be displayed together with an X-ray image, or a single load information may be acquired by averaging the results acquired using the multiple types of load information.

[0080] Furthermore, in the above-described first and second embodiments, an example was shown in which the optical imaging unit 30 was disposed in the collimator unit 12 that defines the irradiation field of the X-ray irradiation unit 10, but the present invention is not limited to this. In the present invention, the optical imaging unit may be disposed in a support unit that supports the X-ray irradiation unit. Also, the optical imaging unit may be disposed in a position separated from the X-ray irradiation unit, such as on the wall or ceiling of the imaging room. For example, the optical imaging unit may be disposed on the X-ray detection unit side. Also, a region of the subject other than the region to be imaged by X-ray imaging may be imaged by the optical imaging unit.

[0081] In the first embodiment, the X-ray image 70 and the optical image 80 are displayed side by side, thereby displaying the X-ray image 70 in association with the optical image 80, but the present invention is not limited to this. In the present invention, when a selection operation for an optical image is accepted, an X-ray image corresponding to the selected optical image may be displayed.

[0082] Furthermore, in the first embodiment, an example was shown in which the frame rate of the X-ray image 70 and the frame rate of the optical image 80 were synchronized so that the timing at which the X-ray image 70 as a moving image was captured and the timing at which the optical image 80 as a moving image was captured were equal, but the present invention is not limited to this. In the present invention, the frame rates of the X-ray image and the optical image may be different from each other. Furthermore, even when the frame rates of the X-ray image and the optical image are equal to each other, the timing at which the X-ray image and the optical image are captured may be different from each other. Similarly, in the case of a load information acquisition unit other than the optical imaging unit, the rate at which load information is acquired may be equal to or different from the frame rate of the X-ray image.

[0083] Furthermore, in the second embodiment, an example was shown in which the maximum load timing was obtained based on the position in the height direction of the other leg of the subject 101, but the present invention is not limited to this. In the present invention, the maximum load timing may be obtained based on the tilt of the subject's body axis. Furthermore, when detecting the position in the height direction of the other leg of the subject, the position in the height direction of the other leg of the subject may be detected by detecting the position of the floor surface in the optical image. Furthermore, the maximum load timing in the loading motion may be detected by detecting movement of parts other than the legs, such as swinging of the arms, based on the optical image.

[0084] Furthermore, in the third embodiment, an example was shown in which the maximum load timing was obtained based on the magnitude of the pressure applied by one leg, based on the detection results of the pressure sensor 330 acquired as load information. However, the present invention is not limited to this. In the present invention, the maximum load timing may be obtained by comparing the pressure applied by one leg with the pressure applied by the other leg, based on the detection results of the pressure sensor acquired as load information. For example, the difference or ratio between the pressure applied by one leg and the pressure applied by the other leg may be obtained. Furthermore, the maximum load timing may be obtained by combining the magnitude of the pressure applied by one leg and a comparison between the pressure applied by one leg and the pressure applied by the other leg. Furthermore, the maximum load timing of one leg may be obtained based on the pressure applied by the other leg.

[0085] In the second and third embodiments, the maximum load timing is acquired, and the X-ray irradiator 10 is caused to irradiate X-rays at the acquired maximum load timing, thereby displaying one X-ray image 70 corresponding to the maximum load timing. However, the present invention is not limited to this. In the present invention, multiple X-ray images may be generated and displayed, and the X-ray image corresponding to the maximum load timing may be displayed in a distinguishable manner. For example, multiple X-ray images may be displayed side by side, and an X-ray image determined to correspond to the maximum load timing may be displayed in a highlighted manner, such as by surrounding it with a frame, so that it can be distinguished from the other X-ray images. In this case, if the acquired maximum load timing differs from the timing at which the multiple X-ray images were captured, an X-ray image captured at a timing close to the maximum load timing may be acquired as the X-ray image corresponding to the maximum load timing. Furthermore, multiple X-ray images and multiple load information (multiple optical images or detection results of a pressure sensor) may be displayed, and the load information corresponding to the maximum load timing among the multiple load information may be displayed in a highlighted manner so that the corresponding X-ray image can be distinguished. Furthermore, when the maximum load timing is not acquired, a numerical value indicating the detection result (load information) acquired by a load information acquisition unit other than the optical imaging unit, such as a pressure sensor, may be displayed in association with (side by side with) the X-ray image, instead of the optical image. Furthermore, when the optical imaging unit is disposed as the load information acquisition unit, detection values ​​such as the leg position acquired based on the optical image may be displayed in association with the X-ray image, instead of the optical image.

[0086] Furthermore, in the second and third embodiments, examples have been shown in which the maximum load timing is determined based on a set judgment threshold value, but the present invention is not limited to this. In the present invention, the maximum load timing may be acquired without setting a judgment threshold value. For example, the maximum load timing may be predicted and acquired by acquiring load information such as an optical image from a subject repeatedly performing a load action at a predetermined cycle and acquiring the cycle required for one load action.

[0087] In the above first to third embodiments, examples have been shown in which the control of X-ray photography, the generation of X-ray images, the control of taking optical images and obtaining the detection results of the pressure sensor (obtaining load information), and the control of obtaining the maximum load timing based on the load information are performed by the control units 50, 250, and 350, but the present invention is not limited to this. In the present invention, one or more of the control of X-ray photography, the generation of X-ray images, the acquisition of load information, and the control of obtaining the maximum load timing may be performed by different control devices, or may be performed by a combination of multiple control devices. Furthermore, the control devices constituting the control unit may be configured by one or more of a personal computer, a processor, a circuit, or an integrated circuit.

[0088] In the first to third embodiments, an example has been shown in which X-ray imaging of the subject 101 performing a loading motion is performed by an X-ray television device in which the X-ray irradiator 10 and the bed 21 on which the X-ray detector 20 is disposed rotate integrally, but the present invention is not limited to this. In the present invention, the X-ray irradiator and the X-ray detector may be disposed apart from each other. For example, X-ray imaging of the subject performing a loading motion may be performed by a ceiling-suspended general X-ray imaging device in which the X-ray irradiator is supported by a support disposed on the ceiling. Furthermore, X-ray imaging of the subject performing a loading motion may be performed by a mobile mobile X-ray imaging device or an X-ray fluoroscopy device with a C-arm.

[0089] [Aspect] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0090] (Item 1) an X-ray irradiation unit that irradiates X-rays onto a subject performing a load-bearing motion that applies a load to the legs; an X-ray detection unit that detects X-rays that have been irradiated from the X-ray irradiation unit and transmitted through the subject; a load information acquisition unit that acquires load information for identifying a state of a load applied to a leg during a weight-bearing motion of the subject, separately from the detection of X-rays by the X-ray detection unit; a display unit that displays an X-ray image generated by the X-ray detection unit; and and a control unit that controls the display unit to identifiably display the X-ray image corresponding to the maximum load timing, which is the timing when the greatest load is applied to at least one of the legs during the subject's loading motion, based on the load information acquired by the load information acquisition unit.

[0091] (Item 2) The control unit controls the display unit to identifiably display the X-ray image corresponding to the maximum load timing of at least one of the ankle joint, knee joint, and hip joint of the one leg based on the load information acquired by the load information acquisition unit.

[0092] (Item 3) 3. The X-ray imaging system according to item 1 or 2, wherein the load information acquisition unit includes at least one of an optical imaging unit that captures an optical image of the subject while the subject is performing a load-bearing motion, and a pressure sensor that detects pressure applied by the subject's legs while the subject is performing a load-bearing motion.

[0093] (Item 4) the load information acquisition unit includes the optical imaging unit that captures the optical image of the subject while the subject is performing a load action, Item 4. The X-ray imaging system according to item 3, wherein the optical imaging unit is disposed on at least one of a support unit that supports the X-ray irradiator and a collimator unit that defines an irradiation field of X-rays irradiated from the X-ray irradiator.

[0094] (Item 5) the load information acquisition unit includes the optical imaging unit that captures the optical image of the subject while the subject is performing a load action, 5. The X-ray imaging system according to item 3 or 4, wherein the control unit displays the X-ray image corresponding to the maximum load timing in association with the optical image captured by the optical imaging unit.

[0095] (Item 6) 6. The X-ray imaging system according to item 5, wherein the control unit displays the X-ray image corresponding to the maximum load timing and the optical image corresponding to the maximum load timing side by side on the display unit.

[0096] (Item 7) The X-ray imaging system according to any one of items 1 to 6, wherein the control unit performs control to distinguishably display on the display unit the X-ray image corresponding to the maximum load timing from among the plurality of X-ray images acquired by continuously irradiating X-rays on the subject performing a load motion.

[0097] (Item 8) Item 8. The X-ray imaging system according to item 7, wherein the control unit controls the display unit to display the X-ray image corresponding to the maximum load timing in a distinguishable manner from the plurality of X-ray images by displaying the plurality of X-ray images including the X-ray image corresponding to the maximum load timing and the load information acquired in synchronization with the detection of X-rays by the X-ray detection unit side by side.

[0098] (Item 9) The control unit acquiring the maximum load timing based on the load information acquired by the load information acquisition unit; 9. The X-ray imaging system according to any one of items 1 to 8, wherein control is performed to display the X-ray image corresponding to the maximum load timing on the display unit in an identifiable manner based on the acquired maximum load timing.

[0099] (Item 10) the load information acquisition unit includes an optical imaging unit that captures an optical image of the subject while the subject is performing a load action; Item 10. The X-ray imaging system according to item 9, wherein the control unit acquires the maximum load timing based on at least one of the position of the other leg of the subject in the height direction and the tilt of the body axis of the subject, based on the optical image acquired as the load information.

[0100] (Item 11) the load information acquisition unit includes a pressure sensor that detects pressure applied by the leg of the subject while the subject is performing a load-bearing motion; Item 10. The X-ray imaging system according to item 9, wherein the control unit acquires the maximum load timing by at least one of the magnitude of the pressure applied by the one leg and a comparison between the pressure applied by the one leg and the pressure applied by the other leg based on the detection result by the pressure sensor acquired as the load information.

[0101] (Item 12) 12. The X-ray imaging system according to any one of items 9 to 11, wherein the control unit is configured to cause the X-ray irradiator to irradiate X-rays at the acquired maximum load timing.

[0102] (Item 13) irradiating an X-ray to a subject who is performing a weight-bearing movement that applies a weight to the leg; detecting X-rays transmitted through the subject; acquiring load information for identifying a state of load applied to a leg during a weight-bearing motion of the subject, separately from detecting X-rays; and displaying an X-ray image generated by detecting the X-rays. The X-ray image display method includes a step of identifiably displaying the X-ray image corresponding to the maximum load timing, which is the timing when the greatest load is applied to at least one of the legs during the subject's loading motion, based on the acquired load information. [Explanation of symbols]

[0103] 10 X-ray irradiation section 12 Collimator section 20 X-ray detection unit 30 Optical imaging unit (load information acquisition unit) 41 Support part 50, 250, 350 control section 60 Display section 70 X-ray images 80 Optical image (load information) 100, 200, 300 X-ray systems 101 Subject 330 Pressure sensor (load information acquisition unit)

Claims

1. an X-ray irradiation unit that irradiates X-rays onto a subject who is performing a load-bearing motion that applies a load to the legs; an X-ray detection unit that detects X-rays irradiated from the X-ray irradiation unit and transmitted through the subject; a load information acquisition unit that acquires load information for identifying a state of a load applied to a leg during a weight-bearing motion of the subject, separately from the detection of X-rays by the X-ray detection unit; a display unit that displays an X-ray image generated by the X-ray detection unit; and a control unit that controls the display unit to identifiably display the X-ray image corresponding to the maximum load timing, which is the timing when the greatest load is applied to at least one of the legs during the subject's loading motion, based on the load information acquired by the load information acquisition unit.

2. 2. The X-ray imaging system according to claim 1, wherein the control unit controls the display unit to identifiably display the X-ray image corresponding to the maximum load timing of at least one of the ankle joint, knee joint, and hip joint of the one leg based on the load information acquired by the load information acquisition unit.

3. 3. The X-ray imaging system according to claim 1, wherein the load information acquisition unit includes at least one of an optical imaging unit that captures an optical image of the subject while the subject is performing a load-bearing motion, and a pressure sensor that detects pressure applied by the subject's legs while the subject is performing a load-bearing motion.

4. the load information acquisition unit includes the optical imaging unit that captures the optical image of the subject while the subject is performing a load action, 4. The X-ray imaging system according to claim 3, wherein the optical imaging unit is disposed on at least one of a support unit that supports the X-ray irradiator and a collimator unit that defines an irradiation field of X-rays irradiated from the X-ray irradiator.

5. the load information acquisition unit includes the optical imaging unit that captures the optical image of the subject while the subject is performing a load action, The X-ray imaging system according to claim 3 , wherein the control unit displays the X-ray image corresponding to the maximum load timing in association with the optical image captured by the optical imaging unit.

6. The X-ray imaging system according to claim 5 , wherein the control unit displays the X-ray image corresponding to the maximum load timing and the optical image corresponding to the maximum load timing side by side on the display unit.

7. 3. The X-ray imaging system according to claim 1, wherein the control unit controls the display unit to distinguishably display the X-ray image corresponding to the maximum load timing from among a plurality of X-ray images acquired by continuously irradiating X-rays on the subject performing a load motion.

8. 8. The X-ray imaging system according to claim 7, wherein the control unit performs control to display the X-ray image corresponding to the maximum load timing in a distinguishable manner from the plurality of X-ray images by displaying the plurality of X-ray images including the X-ray image corresponding to the maximum load timing and the load information acquired in synchronization with the detection of X-rays by the X-ray detection unit side by side on the display unit.

9. The control unit acquiring the maximum load timing based on the load information acquired by the load information acquisition unit; 3. The X-ray imaging system according to claim 1, wherein control is performed to display, on the display unit, the X-ray image corresponding to the maximum load timing in a distinguishable manner based on the acquired maximum load timing.

10. the load information acquisition unit includes an optical imaging unit that captures an optical image of the subject while the subject is performing a load action; 10. The X-ray imaging system according to claim 9, wherein the control unit acquires the maximum load timing based on at least one of a position in a height direction of the other leg of the subject and a tilt of a body axis of the subject, based on the optical image acquired as the load information.

11. the load information acquisition unit includes a pressure sensor that detects pressure applied by the leg of the subject while the subject is performing a load-bearing motion; 10. The X-ray imaging system according to claim 9, wherein the control unit acquires the maximum load timing by at least one of the magnitude of the pressure applied by the one leg and a comparison between the pressure applied by the one leg and the pressure applied by the other leg based on the detection result by the pressure sensor acquired as the load information.

12. The X-ray imaging system according to claim 9 , wherein the control unit is configured to cause the X-ray irradiator to irradiate X-rays at the acquired maximum load timing.

13. irradiating an X-ray to a subject who is performing a weight-bearing motion that applies a load to the leg; detecting X-rays transmitted through the subject; acquiring load information for identifying a state of a load applied to a leg during a weight-bearing motion of the subject, separately from detecting X-rays; and displaying an X-ray image generated by the detection of the X-rays. The X-ray image display method includes a step of identifiably displaying the X-ray image corresponding to a maximum load timing, which is the timing when the greatest load is applied to at least one of the legs during the subject's loading motion, based on the acquired load information.

Images