X-ray imaging apparatus and x-ray imaging method

Abstract

To provide an X-ray imaging apparatus that allows a three-dimensional position of a treatment instrument to be grasped in real time during an operation without rotating a pillar of an X-ray tube.SOLUTION: A first X-ray tube is disposed at a position where a target site of a subject placed on a top plate is irradiated with an X-ray, a second X-ray tube is disposed by rotating the second X-ray tube along a circular orbit around an axis connecting the first X-ray tube and the top plate. A subject is irradiated with an X-ray from the first X-ray tube, and a first X-ray image is acquired. The subject is irradiated with an X-ray from the second X-ray tube, and a second X-ray image is acquired. A three-dimensional position of an image of a predetermined feature site is calculated using the position of an image of a predetermined feature site included in the first X-ray image, and the position of an image of the feature site included in the second X-ray image.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an X-ray imaging apparatus. [Background technology]

[0002] A typical X-ray imaging device irradiates an object with X-rays from an X-ray source and detects the X-rays that pass through the object with a flat X-ray detector, allowing it to take still X-ray images or continuous video X-ray images (so-called fluoroscopy). In both X-ray imaging and fluoroscopy, the X-ray images obtained are two-dimensional projection images, and it is not possible to grasp the position of the structure inside the object in the thickness direction.

[0003] Therefore, in order to enable 3D imaging of a subject, for example, Patent Document 1 proposes an X-ray imaging device in which a multi-X-ray generator consisting of M×N X-ray sources and a flat panel detector consisting of K×L sensors are opposed by an arm. This X-ray imaging device rotates the arm around the sliding rotation axis and the main axis, periodically radiates X-rays from the multiple X-ray sources, synchronously operates the sensors, captures multiple multi-directional images, and reconstructs them based on the coordinate information of the X-ray source, thereby obtaining any multi-layered tomographic image (so-called tomography image).

[0004] Patent Document 2 discloses a so-called biplane X-ray imaging device. This X-ray imaging device is configured such that a first X-ray tube and a first X-ray detector are arranged to face each other by a first C-arm, and a second X-ray tube and a second X-ray detector are arranged to face each other by a second C-arm. The rotation axes of the first C-arm and the second C-arm are set to intersect. A three-dimensional image can be obtained by rotating the first C-arm and the second C-arm to perform imaging. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2013-173015 A [Patent Document 2] JP 2021-133036 A Summary of the Invention [Problem to be solved by the invention]

[0006] A conventional biplane X-ray imaging device as in Patent Document 2 is large and expensive. On the other hand, a multi-tube system using M×N X-ray sources as in Patent Document 1 can switch to another X-ray source when an object to be viewed overlaps with another structure in an image taken using one X-ray source, but the positions of the M×N X-ray sources do not differ greatly, so the degree of freedom in position selection is not large. Therefore, it may not be possible to eliminate the overlap between the object to be viewed and other structures.

[0007] In addition, the devices of Patent Documents 1 and 2 can obtain 3D images and tomographic images of a subject by rotating an arm supporting an X-ray source and an X-ray detector around the subject, but when taking 3D images during surgery, the surgeon must temporarily move away from the subject to avoid contact with the rotating X-ray source and arm. Therefore, it is difficult to take 3D images while inserting surgical tools.

[0008] On the other hand, when the purpose is to determine the position of a device such as a treatment tool, 3D images or tomography images are not necessarily required, so there is a demand for technology that can determine the position of a device without taking 3D images or tomography images.

[0009] An object of the present invention is to provide an X-ray imaging apparatus capable of grasping the three-dimensional position of a device in real time without rotating an arm supporting an X-ray tube during surgery. [Means for solving the problem]

[0010] In order to achieve the above object, the X-ray imaging apparatus of the present invention includes a tabletop on which a subject is placed, a first X-ray tube that irradiates the subject with X-rays, a first support section that supports the first X-ray tube, a second X-ray tube that irradiates the subject with X-rays, a second support section that supports the second X-ray tube, an X-ray detector that detects X-rays irradiated by the first and second X-ray tubes and that have passed through the subject, and a calculation section. The calculation section obtains a first X-ray image from an output of the X-ray detector detecting the X-rays irradiated by the first X-ray tube, obtains a second X-ray image from an output of the X-ray detector detecting the X-rays irradiated by the second X-ray tube, and calculates a three-dimensional position of an image of a predetermined characteristic portion using a position of an image of a predetermined characteristic portion included in the first X-ray image and a position of an image of a characteristic portion included in the second X-ray image. The second support section includes a mechanism that rotatably supports the second X-ray tube along a circular orbit centered on an axis connecting the first X-ray tube and the tabletop. Effect of the Invention

[0011] According to the present invention, it is possible to provide an X-ray imaging apparatus capable of grasping the three-dimensional position of a treatment tool in real time during an operation without rotating the support column of the X-ray tube. [Brief description of the drawings]

[0012] [Figure 1] 1 is a block diagram showing the arrangement and movement directions of two X-ray tubes when the X-ray imaging apparatus 1 according to the first embodiment of the present invention is viewed from the side. [Diagram 2] 1 is a block diagram showing the configuration of a main part of an X-ray imaging apparatus 1 according to a first embodiment. [Diagram 3] 4 is a timing chart showing the timing of supplying tube current to the first X-ray tube 60 and the second X-ray tube 110 of the X-ray imaging apparatus 1 of the first embodiment, and the timing of collecting data from the X-ray detector. [Figure 4] (a) An explanatory diagram showing the three-dimensional positions S1, S2 of the first X-ray tube 60 and the second X-ray tube 110 of the X-ray imaging device 1 of embodiment 1, and the three-dimensional positions D1, D2 of the characteristic part of the treatment tool projected onto the X-ray detector 70, (b) a diagram showing an example of the first X-ray image, (c) a diagram showing an example of the second X-ray image, and (d) a diagram showing a method of calculating the three-dimensional position of the characteristic part of the treatment tool. [Diagram 5]FIG. 4 is a flowchart showing the operation of the X-ray imaging apparatus 1 of the first embodiment. [Figure 6] 4 is a view showing an example of a screen displayed on a display unit of the X-ray imaging apparatus 1 of the first embodiment. [Figure 7] FIG. 11 is a block diagram showing the arrangement and movement directions of two X-ray tubes when the X-ray imaging device 1 of the second embodiment is viewed from the side. [Figure 8] FIG. 11 is a block diagram showing the arrangement and movement directions of two X-ray tubes when the X-ray imaging device 1 of the third embodiment is viewed from the side. [Figure 9] FIG. 11 is a block diagram showing the configuration of the main parts of an X-ray imaging device 2 according to a fourth embodiment. [Figure 10] (a) An explanatory diagram showing how a pre-captured 3D image acquired by the X-ray imaging device 2 of embodiment 4 is projected to calculate a 2D projection image; (b) A diagram showing an example of a first 2D projection image and a first X-ray image; (c) A diagram showing an example of a second 2D projection image and a second X-ray image. [Figure 11] FIG. 11 is a flowchart showing the operation of the X-ray imaging apparatus 2 of the fourth embodiment. [Figure 12] 13 is a view showing an example of a screen displayed on a display unit of the X-ray imaging apparatus 2 of the fourth embodiment. [Figure 13] 13A is a diagram showing the positional relationship of the tumor and spinal cord of a subject 101 relative to the first X-ray tube 60 and the second X-ray tube 110 of the X-ray imaging apparatus of embodiment 5, and (b) and (c) are diagrams showing a second X-ray image of embodiment 5. FIG. [Figure 14] (a) A diagram showing the relationship between the grid and the direction of X-ray incidence in embodiment 7, (b) a diagram showing an arrangement in which the optical axis of the second X-ray tube 110 and the direction of the grid rows intersect, and (c) a diagram showing an arrangement in which the optical axis of the second X-ray tube 110 and the direction of the grid rows are parallel. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0014] <<Embodiment 1>> The configuration of an X-ray imaging device 1 according to the embodiment will be described.

[0015] Fig. 1 is a diagram showing the arrangement and movement direction of two X-ray tubes when each is viewed from the side of the X-ray imaging device 1. Fig. 2 is a block diagram showing the configuration of the main parts of the X-ray imaging device 1. Fig. 3 is a diagram showing the timing of supplying tube current to the two X-ray tubes and the timing of collecting data from the X-ray detector.

[0016] 1 and 2, the X-ray imaging device 1 includes a tabletop 40 on which a subject is placed, and a first X-ray tube 60 and a second X-ray tube 110 that irradiate the subject with X-rays. The first X-ray tube 60 is supported by a first support section 120. The second X-ray tube 110 is supported by a second support section 130. The X-rays irradiated by the first X-ray tube 60 and the second X-ray tube 110 pass through the subject 101. An X-ray detector 70 is disposed within the tabletop 40 at a position where the X-rays that have passed through the subject 101 are irradiated.

[0017] The first support portion 120 includes a column 50 supported by the stand 10 and a first X-ray support arm 90 .

[0018] The second support unit 130 includes a mechanism for supporting the second X-ray tube 110 rotatably along a circular orbit 111 centered on an axis 61 connecting the first X-ray tube 60 and the top board 40. The axis 61 may or may not coincide with the optical axis of the first X-ray tube 60. If the first X-ray tube 60 is provided with a swing mechanism that is rotatable in either direction at the connection portion with the first support unit 120, the axis 61 may not coincide with the optical axis of the first X-ray tube 60.

[0019] A specific structural example of the second support unit 130 will be described with reference to Fig. 1. The second support unit 130 includes an arm 131, a support shaft 132, and a rotation mechanism 133. The support shaft 132 is provided at a position supporting the first X-ray tube 60 of the first support unit 120. Here, the support shaft 132 is provided below the tip of the first X-ray support arm 90 of the first support unit 120, and the first X-ray tube 60 is supported at the lower end of the support shaft 132.

[0020] The arm 131 has a base 131a and a tip, and the base 131a is supported by a support shaft 132. The rotation mechanism 133 is a mechanism for rotating the base 131a of the arm 131 around the support shaft 132. For example, the rotation mechanism 133 can be configured to include a guide rail provided along the circumferential direction of the outer periphery of the support shaft 132, and an engagement portion provided on the base 131a of the arm 131 and engaging with the guide rail. With this configuration, the arm 131 can be rotated along the outer periphery of the support shaft 132. The second X-ray tube 110 is supported on the tip 131b of the arm 131. This allows the second X-ray tube 110 to rotate around the first X-ray tube 60 along a circular orbit 111 centered on the axis 61.

[0021] Furthermore, the second support unit 130 may be provided with a drive unit that changes the position of the second X-ray tube 110 along the circular orbit 111, although the user may manually rotate the second X-ray tube 110 along the circular orbit 111. For example, by forming the guide rail of the rotation mechanism 133 into a rack structure, arranging a pinion that meshes with the rack structure in an engagement unit, and arranging a motor that rotates the pinion as a drive unit, the second X-ray tube 110 can be rotationally moved along the circular orbit 111 by the amount of rotation of the motor.

[0022] The second support part 130 may be provided with a stopper that switches the second X-ray tube 110 from a state in which it can rotate along the circular orbit 111 to a fixed state. For example, a retractable protrusion provided around the support shaft 132 can be used as the stopper. By protruding the protrusion, the rotation of the arm 131 is prevented, and the second X-ray tube 110 can be fixed.

[0023] Furthermore, the second support part 130 can also be configured to include a mechanism for changing the radius of the circular orbit 111. For example, an extension mechanism 134 that enables the arm 131 to be extended or retracted is disposed inside the arm 131. Specifically, a slide rail mechanism can be used as the extension mechanism 134. This allows the arm 131 to be extended or retracted to a desired length, and the radius of the circular orbit 111 can be changed.

[0024] 1, the relationship between the height of the first X-ray tube 60 and the height of the circular orbit 111 of the second X-ray tube 110 can be set to a desired relationship. For example, as shown in FIG. 1, the height of the circular orbit 111 of the second X-ray tube 110 can be set to approximately the same height as the height of the first X-ray tube 60.

[0025] The configuration of the second support part 130 is not limited to the above-mentioned structure, and may be any configuration capable of rotating the second X-ray tube 110 along the circular orbit 111, and the second support part 130 may be directly installed on the stand 10.

[0026] In this way, by making the structure rotatable around the first X-ray tube 60 along the circular orbit 111 of the second X-ray tube 110, even if a characteristic part (e.g., the tip of a treatment tool such as a catheter) whose position within the subject 101 is to be detected in an image captured by the second X-ray tube 110 overlaps with a structure such as the bone of the subject 101 and the image of the characteristic part cannot be grasped on the image, it is possible to rotate the second X-ray tube 110 to capture an image from a different angle and detect the position of the characteristic part.

[0027] The following describes a configuration for controlling and calculating the X-ray imaging device 1. The X-ray imaging device 1 has an arithmetic control unit 150 as shown in Fig. 2, in which a calculation unit 140, a drive control unit 151, an output control unit 152, a data collection unit 154, and a high voltage generator 153 are arranged.

[0028] The calculation unit 140 includes an X-ray image generation unit 141, a characteristic portion extraction unit 142, and a three-dimensional position calculation unit 143. The X-ray image generation unit 141 acquires a first X-ray image from an output of the X-ray detector 70 detecting the X-rays irradiated by the first X-ray tube 60, and acquires a second X-ray image from an output of the X-ray detector 70 detecting the X-rays irradiated by the second X-ray tube 110. The characteristic portion extraction unit 142 extracts the position of an image of a predetermined characteristic portion included in the first X-ray image and the position of an image of a characteristic portion included in the second X-ray image. The three-dimensional position calculation unit 143 calculates the three-dimensional position of the image of the predetermined characteristic portion from the extraction result of the characteristic portion extraction unit 142.

[0029] The maximum irradiation area of ​​the X-rays from the second X-ray tube 110 onto the X-ray detector 70 may be smaller than the maximum irradiation area of ​​the X-rays from the first X-ray tube 60 onto the X-ray detector 70 .

[0030] Furthermore, the maximum output of X-rays from the second X-ray tube 110 may be smaller than the maximum output of X-rays from the first X-ray tube 60 .

[0031] A second slide mechanism 52 is provided in the first X-ray support arm 90 of the first support section 120 that supports the first X-ray tube 60, and moves the position of the first X-ray tube 60 in the width direction (A5 direction = x direction) of the tabletop 40. Here, since the support shaft 132 and the second X-ray tube 110 are also supported by the first X-ray support arm 90, the second X-ray tube 110 also moves together with the first X-ray tube 60.

[0032] Furthermore, a first rotation mechanism 53 that rotates the first X-ray tube 60 (in the A6 direction) at the tip of the first X-ray support arm 90 (the lower end of the support shaft 132 in Figure 1) around an axis parallel to the long axis (y-axis) of the tabletop 40 is disposed at the connection between the first X-ray tube 60 and the support shaft 132.

[0033] In this embodiment, the pillar 50 of the first support unit 120 is mounted on a pillar support arm 20 provided on the stand 10. A first slide mechanism 51 is provided between the lower end of the pillar 50 of the first support unit 120 and the pillar support arm 20, for moving the lower end of the pillar 50 in the width direction (A4 direction = x direction) of the tabletop 40 relative to the stand 10. The first slide mechanism 51 moves the first support unit 120 and the second support unit 130 together in the x direction.

[0034] The column support arm 20 is equipped with not only the first support section 120 but also a support frame 30 that supports the top board 40. The stand 10 has a built-in drive mechanism 221 that moves the column support arm 20 up and down (A1 direction=z axis). This allows the top board 40, the first X-ray tube 60, and the second X-ray tube 110 to be raised and lowered while maintaining the positional relationship between the first X-ray tube 60 and the top board 40.

[0035] Further, the column support arm 20 of the stand 10 has a built-in movement mechanism 224 for moving the first support part 120 in the longitudinal direction (A3 direction=y-axis) of the tabletop 40. This allows the first X-ray tube 60 and the second X-ray tube 110 to move in the longitudinal direction (y-axis) of the tabletop 40 relative to the tabletop 40.

[0036] The stand 10 is also provided with a lifting / tilting mechanism 223 that rotates (in the direction of A9) the column support arm 20 about the central axis (x-axis) of the column support arm 20. This allows the top board 40 to be lifted or tilted while maintaining the positional relationship between the first X-ray tube 60 and the top board 40.

[0037] Furthermore, the column support arm 20 is provided with a tilting mechanism (not shown) at the connection portion with the first support part 120, which rotates the first support part 120 relative to the column support arm 20 around the central axis (x-axis) of the column support arm 20 as the center of rotation along a semicircular rail. This allows the first support part 120 to be tilted relative to the tabletop 40 around the x-axis as the center of rotation.

[0038] Furthermore, although not shown, a drive mechanism (not shown) for moving the X-ray detector 70 relative to the top board 40 in the long axis direction and the short axis direction of the top board 40 is provided within the top board 40.

[0039] Each of the driving mechanisms 51 to 53, 133 to 134, 221, 224 to 224 may have any configuration. As an example, the driving mechanisms may have a configuration including a rack arranged along the movement direction, a pinion that meshes with the rack, and a motor that rotates the pinion.

[0040] The arithmetic and control unit 150 includes a drive control unit 151 that controls the operations of the above-mentioned drive mechanisms 51 to 53, 133 to 134, 221, 223 to 224, an output control unit 152, a high voltage generator 153, a data collection unit 154, and a calculation unit 140.

[0041] The output control unit 152 supplies the high voltage generated by the high voltage generator 153 to the first X-ray tube 60 and the second X-ray tube 110 at the respective set voltage and current values ​​at the timings shown in Fig. 3, causing the first X-ray tube 60 and the second X-ray tube 110 to irradiate X-rays. The output control unit 152 can control the outputs of the first X-ray tube 60 and the second X-ray tube 110 individually.

[0042] The data collection unit 154 collects signals outputted upon receiving X-ray irradiation from the X-ray detection elements arranged two-dimensionally in the X-ray detector 70, at the timing shown in Fig. 3. The data collection unit 154 also obtains information on the start and end of irradiation from each X-ray tube from the tube current and tube voltage controlled by the output control unit 152.

[0043] As already described, the calculation unit 140 includes an X-ray image generation unit 141, a characteristic portion extraction unit 142, and a three-dimensional position calculation unit 143. The X-ray image generation unit 141 receives an output of the X-ray detector 70 detecting the X-rays irradiated by the first X-ray tube from the data collection unit 154, and generates a first X-ray image (see FIG. 4(b)). Also, the X-ray image generation unit 141 receives an output of the X-ray detector 70 detecting the X-rays irradiated by the second X-ray tube from the data collection unit 154, and generates a second X-ray image (see FIG. 4(c)).

[0044] The characteristic part extraction unit 142 extracts the position of the image of a specific characteristic part included in the first X-ray image and the position of the image of a characteristic part included in the second X-ray image by a known method. The characteristic part is, for example, the tip of a treatment tool such as a catheter.

[0045] The three-dimensional position calculation unit 143 calculates the three-dimensional position of the predetermined characteristic portion using the position of the image of the predetermined characteristic portion included in the first X-ray image and the position of the image of the characteristic portion included in the second X-ray image.

[0046] A specific example of a method for calculating a characteristic portion will be described. As shown in FIG. 4(a), the three-dimensional position (real space coordinates) of the first X-ray tube 60 is S1, the three-dimensional position (real space coordinates) of the characteristic portion in the first X-ray image is D1, and the straight line connecting S1 and D1 is L1. The three-dimensional position of the second X-ray tube 110 is S2, the three-dimensional position of the characteristic portion in the second X-ray image is D2, and the straight line connecting S2 and D2 is L2. D1 and D2 are projections of a characteristic portion such as the tip of the same treatment tool. Therefore, the straight lines L1 and L2 ideally intersect at one point as shown in FIG. 4(a). In reality, as shown in FIG. 4(d), they may not intersect due to measurement errors or the like. Therefore, a point Q1 on the straight line S1-D1 and a point Q2 on the straight line S2-D2 where the distance between the two straight lines is the shortest are obtained, and for example, the midpoint u of the two points can be set as the position of the image of the characteristic portion.

[0047] Points Q1 and Q2 shown in FIG. 4(d) can be determined according to the following formula 1.

[0048] Q1=S1+(D1-D2*Dv) / (1-Dv*Dv)*v1 Q2=S2+(D2-D1*Dv) / (Dv*Dv-1)*v2 ···(1) however, D1 = (S2 - S1) v1 D2 = (S2-S1)v2 Dv = v1 v2

[0049] From the three-dimensional positions of points Q1 and Q2 obtained by the above equations, the three-dimensional position u of the characteristic portion can be calculated using the following equation 2.

[0050] u=(Q1+Q2) / 2 ···(2) Next, the operation of each part when detecting the three-dimensional position of the tip of a treatment tool (device) during surgery under an X-ray fluoroscopic image by the X-ray imaging apparatus 1 of this embodiment will be described with reference to the flow of FIG.

[0051] (Step 600) The subject 101 is placed on the tabletop 40, and the user operates the driving mechanisms 51-53, 221, 223-224 under the control of the driving control unit 151 to place the first X-ray tube 60 at a position where the target site where the device is to be inserted can be imaged. Based on the target site and / or the advance information of the device to be used, the user also moves the second X-ray tube 110 along the circular orbit 111 by the mechanisms 133-134 to place the second X-ray tube 110 at a position where the tip of the device to be inserted can be imaged from a direction that does not overlap with bones such as the spine or organs such as the liver. At this time, the distance between the first X-ray tube 60 and the second X-ray tube 110 may be adjusted by adjusting the length of the arm 131 by the extension mechanism 134.

[0052] (Step 601) When an instruction to start the operation is given by the operator, as shown in FIG. 3, a tube current is supplied to the first X-ray tube 60, the first X-ray tube 60 irradiates the subject 101 with X-rays, and X-ray imaging is started.

[0053] (Step 602) The X-ray image generating unit 141 obtains an X-ray image using the X-rays emitted by the first X-ray tube 60 .

[0054] Specifically, X-rays irradiated from the first X-ray tube 60 and passing through the subject 101 are detected by the X-ray detector 70, and the output of the X-ray detector 70 is collected by the data collection unit 154 at the timing shown in FIG. 3.

[0055] The X-ray image generating unit 141 receives the output of the X-ray detector 70 from the data collecting unit 154 and generates a first X-ray image (see FIG. 4(b)). The X-ray image generating unit 141 displays the first X-ray image on the display unit 160.

[0056] While viewing the first X-ray image on the display unit 160, the surgeon inserts a treatment tool (catheter, etc.) into the subject.

[0057] (Step 603) The characteristic portion extraction unit 142 processes the first X-ray image generated in step 602, and extracts a characteristic portion of the treatment tool (for example, the tip of the treatment tool) in the first X-ray image.

[0058] (Step 604) The three-dimensional position calculation unit 143 calculates a position D1 (real space coordinates) on the X-ray detector 70 where the characteristic portion of the treatment tool is projected, based on the position of the treatment tool in the first X-ray image.

[0059] (Step 605) The three-dimensional position calculation unit 143 calculates a straight line L1 connecting two points, the position D1 (real space coordinates) of the treatment tool characteristic portion on the X-ray detector and the position S1 (real space coordinates) of the first X-ray tube 60.

[0060] (Step 606) As shown in FIG. 3, at the timing when the X-ray irradiation from the first X-ray tube 60 ends, the second X-ray tube 110 irradiates the subject 101 with X-rays, and X-ray imaging is performed.

[0061] Specifically, the output control unit 152 stops the supply of tube current and tube voltage to the first X-ray tube 60, supplies the tube current and tube voltage set by the operator to the second X-ray tube 110, and irradiates X-rays for only a specified period of time.

[0062] (Step 607) The X-ray image generating unit 141 obtains an X-ray image using the X-rays emitted by the second X-ray tube 110 .

[0063] Specifically, X-rays irradiated from the second X-ray tube 110 and passing through the subject 101 are detected by the X-ray detector 70, and the output of the X-ray detector 70 is collected by the data collection unit 154 at a predetermined timing shown in FIG. 3.

[0064] The X-ray image generating unit 141 receives the output of the X-ray detector 70 from the data collecting unit 154 and generates a second X-ray image (see FIG. 4(c)).

[0065] This allows the surgeon to check on the display unit 160 the second X-ray image captured from an angle different from that of the first X-ray image.

[0066] (Step 608) The characteristic portion extraction unit 142 processes the second X-ray image generated in step 607, and extracts the characteristic portion of the treatment tool (the tip of the treatment tool) in the second X-ray image.

[0067] (Step 609) The three-dimensional position calculation unit 143 calculates a position D2 (real space coordinates) on the X-ray detector 70 where the characteristic portion of the treatment tool is projected, based on the position of the treatment tool in the second X-ray image.

[0068] (Step 610) The three-dimensional position calculation unit 143 calculates a straight line L2 connecting two points, that is, the position D2 (real space coordinates) of the characteristic portion of the treatment tool on the X-ray detector and the position S2 (real space coordinates) of the second X-ray tube 110.

[0069] (Step 611) The three-dimensional position calculation section 143 calculates the three-dimensional position of the characteristic portion of the treatment tool from the positional relationship of the two straight lines L1 and L2 using the above-mentioned formulas 1 and 2.

[0070] (Step 612) The three-dimensional position calculation unit 143 displays the calculated three-dimensional position of the characteristic part of the treatment tool at the current time, for example, as in three-dimensional image 702 in Fig. 6. As a result, the first X-ray image 701 and the three-dimensional image 702 showing the positions of the characteristic parts of the treatment tool in chronological order are displayed side by side on the display screen of the display unit 160. The surgeon can grasp the projection images of the subject 101 and the treatment tool from the first X-ray image 701, and can also grasp the change over time in the depth of the tip of the treatment tool from the three-dimensional image 702.

[0071] (Step 613) If an instruction to continue imaging is confirmed from the operator, and imaging is continued, the process returns to step 601 to continue imaging with the first X-ray tube 60, and imaging is performed with the second X-ray tube 110 at regular time intervals in steps 606 to 610, the position of the characteristic part of the treatment tool is calculated, and the display is updated. As a result, the position of the characteristic part of the treatment tool is acquired in chronological order at regular time intervals.

[0072] As described above, the X-ray imaging device 1 of this embodiment includes the second X-ray tube 110, which can be moved along a circular orbit 111 around the first X-ray tube 60, and while imaging is being performed from the first X-ray tube 60 during surgery, the device can be imaged by the second X-ray tube 110 from a direction in which the treatment tool (device) does not overlap with bones or other organs. Thus, the X-ray imaging device 1 of this embodiment has a simple configuration, but can grasp the three-dimensional position of a characteristic part of the treatment tool in real time.

[0073] Furthermore, in the flow of FIG. 5, after steps 601, 602, 606, and 607 are performed, the first X-ray image and the second X-ray image are displayed on the display unit 160 as shown in FIGS. 4(b) and (c). Therefore, before the device position is calculated, the user can refer to the first and second X-ray images taken of the device from multiple directions and can grasp the position and orientation of the treatment tool (device).

[0074] In the above embodiment, extraction of characteristic portions of the device from the first X-ray image in steps 603 to 605 is performed before or in parallel with capturing the second X-ray image by the second X-ray tube 110 in steps 606 and 607, but steps 603 to 605 may also be performed after steps 606 and 607.

[0075] In addition, a small X-ray tube with low output and narrow irradiation range can be used as the second X-ray tube 110, and since the second X-ray tube 110 can be moved along the circular orbit 111, the second X-ray tube 110 does not interfere with the imaging of the first X-ray tube 60 or with the surgeon. Therefore, imaging can be performed in real time during surgery by the first X-ray tube 60 and the second X-ray tube 110.

[0076] <<Embodiment 2>> The X-ray imaging apparatus of the second embodiment will be described with reference to FIG.

[0077] In the X-ray imaging apparatus of the second embodiment, the first X-ray tube 60 is directly supported by the first X-ray support arm 90, and the support shaft 132 is erected on the upper surface of the first X-ray support arm 90. The base 131a of the arm 131 rotates around the support shaft 132. This allows the second X-ray tube 110 to rotate along the circular orbit 111.

[0078] The other structure and operation are similar to those of the first embodiment, so the description will be omitted.

[0079] <<Embodiment 3>> The X-ray imaging apparatus according to the third embodiment will be described with reference to FIG.

[0080] The X-ray imaging apparatus of the third embodiment includes a plurality of second X-ray tubes 110. The plurality of second X-ray tubes 110 are configured to rotate around a support shaft 132 by a plurality of arms 131. The plurality of second X-ray tubes 110 may be disposed symmetrically with respect to the first X-ray tube 60, or may be disposed asymmetrically.

[0081] The X-ray imaging apparatus of the third embodiment can capture images of a target site or treatment tool (device) from multiple directions using multiple second X-ray tubes 110, and therefore can obtain more information.

[0082] The support shaft 132 may be provided below the first X-ray support arm 90 as in the first embodiment, or above the first X-ray support arm 90 as in the second embodiment.

[0083] The other configurations and operations are similar to those of the first embodiment, and therefore the description thereof will be omitted.

[0084] <<Embodiment 4>> The X-ray imaging device 2 of the fourth embodiment has a function of generating a two-dimensional projection image in a direction desired by the surgeon from a three-dimensional image captured in advance by a CT device, an MRI device, or the like, and displaying the position of a characteristic part of a treatment tool on the generated two-dimensional projection image.

[0085] Other configurations of the X-ray imaging device 2 are similar to those of the first embodiment, so descriptions of the same configurations and operations as those of the first embodiment will be omitted.

[0086] Fig. 9 is a block diagram showing the configuration of the main parts of the X-ray imaging device 2 of embodiment 4. Figs. 10(a) to (c) are diagrams explaining how a pre-captured three-dimensional image is projected to generate a two-dimensional projected image.

[0087] The X-ray imaging apparatus 2 has a configuration similar to that of the X-ray imaging apparatus 1 of the first embodiment, but differs from the first embodiment in that a calculation unit 140 includes a three-dimensional image acquisition unit 144, a two-dimensional projection image creation unit 145, and an image registration unit 146. The three-dimensional image acquisition unit 144 is connected to an external medical image server 170. The medical image server 170 stores three-dimensional images of the subject 101 that have been captured in advance by a CT device or an MRI device.

[0088] The operation of the X-ray imaging device 2 will be described with reference to the flow chart of FIG.

[0089] The flow in FIG. 11 is configured by adding steps 801 to 808 and 809 to the flow in FIG. 5 of the first embodiment.

[0090] (Step 600) First, in step 600 of the flow in FIG. 5 of embodiment 1, the user positions the first X-ray tube 60, and based on prior information on the target site and / or the device to be used, the user moves the second X-ray tube 110 along the circular orbit 111 and positions the second X-ray tube 110 in a position where it can image the tip of the device to be inserted, in an orientation that does not overlap with bones such as the spine or organs such as the liver.

[0091] (Step 801) Next, the three-dimensional image acquiring unit 144 acquires, from the medical image server 170, a three-dimensional image of the subject 101 that has been captured in advance.

[0092] (Step 802) The first X-ray tube 60 irradiates the subject 101 with X-rays, and the X-ray image generating unit 141 obtains a first X-ray image.

[0093] (Step 803) As shown in FIG. 10(a), the two-dimensional projection image creation unit 145 places a simulated first X-ray tube 60 and a simulated X-ray detector 70 relative to the pre-captured three-dimensional image in the same positional relationship as the first X-ray tube 60 and the X-ray detector 70 in step 802, projects the pre-captured three-dimensional image onto the simulated X-ray detector 70, and calculates a first two-dimensional projection image.

[0094] (Step 804) 10(b), the image registration unit 146 compares the first X-ray image acquired in step 802 with the first two-dimensional projection image calculated in step 803. If they are different, the position of the pre-captured three-dimensional image relative to the simulated first X-ray tube 60 and the simulated X-ray detector 70 is changed, and the first two-dimensional projection image is calculated again and compared with the first X-ray image acquired in step 802. This is repeated until the first X-ray image acquired in step 802 and the first two-dimensional projection image calculated in step 803 match.

[0095] (Step 805) Next, the second X-ray tube 110 irradiates the subject 101 with X-rays, and the X-ray image generating unit 141 obtains a second X-ray image.

[0096] (Step 806) As shown in FIG. 10(a), the two-dimensional projection image creation unit 145 places a simulated second X-ray tube 110 and a simulated X-ray detector 70 relative to the pre-captured three-dimensional image in the same positional relationship as the second X-ray tube 110 and the X-ray detector 70 in step 805, projects the pre-captured three-dimensional image onto the simulated X-ray detector 70, and calculates a second two-dimensional projection image.

[0097] (Step 807) 10(c), the image registration unit 146 compares the second X-ray image acquired in step 805 with the second two-dimensional projection image calculated in step 806. If they are different, the position of the pre-captured three-dimensional image relative to the simulated second X-ray tube 110 and the simulated X-ray detector 70 is changed, and a second two-dimensional projection image is calculated again and compared with the second X-ray image acquired in step 805. This is repeated until the second X-ray image acquired in step 805 and the second two-dimensional projection image calculated in step 806 match.

[0098] (Step 808) The image registration unit 146 calculates a parameter for associating the coordinate system of the pre-captured three-dimensional image with real space coordinates from the position of the pre-captured three-dimensional image with respect to the simulated first X-ray tube 60 and the simulated X-ray detector 70 when the first X-ray image acquired in step 802 and the first two-dimensional projection image calculated in step 803 match (registration). Similarly, a parameter for associating the coordinate system of the pre-captured three-dimensional image with real space coordinates is calculated from the position of the pre-captured three-dimensional image with respect to the simulated first X-ray tube 60 and the simulated X-ray detector 70 when the second X-ray image acquired in step 805 and the second two-dimensional projection image calculated in step 806 match (registration). Here, since the parameters obtained from the first X-ray image and the parameters obtained from the second X-ray image are obtained, the parameters for associating the coordinate system of the pre-captured three-dimensional image with real space coordinates are obtained by selecting one of them or by calculating the average, etc.

[0099] (Steps 601 to 612) Steps 601 to 612 are executed in the same manner as in the first embodiment, the current three-dimensional position of the characteristic part of the treatment tool is calculated, and an image 702 indicating the calculated position and a first X-ray image 701 are displayed on the display unit 160.

[0100] (Step 809) Using parameters that associate the coordinate system of the pre-captured 3D image obtained in step 808 with real space coordinates, the coordinates are converted into real space coordinates of the pre-captured 3D image, and then the image is two-dimensionally projected in a direction desired by the surgeon to calculate a calculated projection image 703. The position of the characteristic part of the treatment tool calculated in step 611 is superimposed on the calculated calculated projection image 703 and displayed as shown in FIG.

[0101] According to the X-ray imaging device 2 of the fourth embodiment, the positions of the characteristic parts of the treatment tool recognized in real time can be displayed on a two-dimensional projected image obtained by projecting the pre-captured three-dimensional image in a direction specified by the surgeon, making it easy to understand the correspondence between the positions of the characteristic parts of the treatment tool and the anatomical structure of the subject.

[0102] As in the first embodiment, steps 603 to 605 in FIG.

[0103] <<Embodiment 5>> In the above-mentioned first and fourth embodiments, in step 600, the user moves the second X-ray tube 110 along the circular orbit 111 based on prior information about the target area and / or the device to be used, and places the second X-ray tube 110 in a position where it can image the tip of the device to be inserted in an orientation that does not overlap with bones such as the spine or organs such as the liver.

[0104] In the fifth embodiment, the user does not decide the position of the second X-ray tube 110, but the X-ray imaging apparatus moves the second X-ray tube 110 to an appropriate position or prompts the user to move it to an appropriate position.

[0105] For example, as shown in FIG. 13(a), if a tumor is taken as an example of a target, when the tumor is located near the spine extending in the body axis direction, the X-ray imaging device detects this by the following detection means. Specifically, the characteristic site extraction unit 142 functions as a detection means, extracts the tumor and spine from the first X-ray image taken by the first X-ray tube 60 or the second X-ray image taken by the second X-ray tube 110, and checks whether the positional relationship between the extracted tumor and the spine overlaps. Alternatively, the user inputs the positions of the tumor and the spine to the X-ray imaging device as the determination target of "site superposition" by pointing to the positions of the tumor and the spine on the first X-ray image or the second X-ray image using a pointing device or the like. The X-ray imaging device checks whether the positional relationship between the tumor and the spine input by the user overlaps. Alternatively, the user may specify only the tumor position using a pointing device or the like, and the position of the spine may be extracted by the characteristic site extraction unit 142.

[0106] When the X-ray imaging device detects that the tumor and the spine are overlapping (see FIG. 13(b)), a display is displayed to prompt the user to place the second X-ray tube 110 so that the angle at which the second X-ray tube 110 views the spine is different from that of the first X-ray tube 60, that is, at a position shifted in the left-right direction with respect to the central axis (spine) of the subject 101. The user adjusts the position of the second X-ray tube 110 based on this display. Alternatively, the X-ray imaging device may be configured such that the user approves the adjustment of the position of the second X-ray tube 110 by the X-ray imaging device. In the latter case, the X-ray imaging device moves the position of the second X-ray tube 110 by a predetermined amount, or moves the second X-ray tube 110 so that the tumor and the spine do not overlap in the second X-ray image.

[0107] When the second X-ray tube 110 is placed in the left-right direction with respect to the spine, a second X-ray image is obtained in which the tumor and the spine do not overlap (see FIG. 13(c)). As a result, the tip of the device inserted toward the tumor does not overlap the spine, and the S / N ratio of the image of the tip of the device in the first X-ray image and the second X-ray image can be ensured.

[0108] <<Embodiment 6>> In the fifth embodiment, the X-ray imaging device is configured to detect when the tumor and the spine overlap, but if the user looks at the first or second X-ray image and finds that the tumor and the spine overlap and it is difficult to see them, the user may press an "overlap removal button" that is prepared on the screen in advance.

[0109] When the overlap removal button is pressed by the user, the X-ray imaging apparatus moves the position of the second X-ray tube 110 by a predetermined amount.

[0110] This allows a second X-ray image to be obtained in which the tumor and spine are not overlapped.

[0111] <<Embodiment 7>> When a treatment tool (device) is inserted and moved by the operator during a procedure, there is a possibility that the device may go outside the image (second X-ray image) captured by the second X-ray tube 110. Therefore, when the characteristic part extraction unit 142 extracts a characteristic part of the device and the position of the characteristic part is within a region of, for example, 10% from the edge of the field of view of the second X-ray image, the calculation unit 140 may take the following action.

[0112] For example, the calculation unit 140 displays a display prompting the user to move the position of the second X-ray tube 110, and the user moves the position of the second X-ray tube 110 along the circular orbit 111 so that the characteristic portion comes within the field of view of the second X-ray image. Alternatively, the calculation unit 140 instructs the drive control unit 151 to move the position of the second X-ray tube 110 by a predetermined amount along the circular orbit 111 so that the characteristic portion comes within the field of view of the second X-ray image. In the latter case, before the calculation unit 140 moves the position of the second X-ray tube 110, the calculation unit 140 may confirm with the user whether it is OK to change the position of the second X-ray tube 110.

[0113] In addition, the calculation unit 140 may change the position of the second X-ray tube 110 not only by moving the second X-ray tube 110 along the circular orbit 111, but also by moving the second X-ray tube 110 along the circular orbit 111 and extending and retracting the arm 131 using the extension mechanism 134.

[0114] That is, in embodiment 7, the calculation unit 140 can cause the field of view of the second X-ray image to follow the movement of the characteristic feature by, for example, driving the rotation mechanism 133 to move the second X-ray tube 110 according to the position of the characteristic feature contained in the second X-ray image.

[0115] <<Embodiment 8>> The X-ray imaging apparatus of the eighth embodiment has the same configuration as the first to fourth embodiments, but further includes a grid having a plurality of parallel ridges arranged on the X-ray detector, and a rotation drive unit that rotates the grid within the main plane. The rotation drive unit rotates the grid according to the position on the circular orbit of the second X-ray tube.

[0116] The grid has the effect of reducing scattered radiation in the X-ray detector, but depending on the position on the circular orbit 111 of the second X-ray tube 110, the S / N ratio of the X-ray detector decreases.

[0117] Specifically, as shown in Figures 14(a) and 14(b), when the optical axis (X-ray irradiation direction) of the second X-ray tube 110 is oriented to intersect with the longitudinal direction of the ridges of the grid, the shadow of the grid is prominently cast on the X-ray detector 70, lowering the S / N ratio of the output of the X-ray detector 70. Therefore, as shown in Figure 14(c), the S / N can be maintained by rotating the grid so that the optical axis of the second X-ray tube 110 is parallel to the longitudinal direction of the ridges of the grid.

[0118] Specifically, the rotation drive unit includes a mechanism for rotating the grid within the main plane within the tabletop 40. The rotation drive unit may rotate the grid in synchronization with the rotation of the second X-ray tube 110.

[0119] In addition, after detecting via the drive control unit 151 that the position of the second X-ray tube 110 has been fixed (that the position information no longer fluctuates), the rotation drive unit may automatically rotate the grid based on the position information of the second X-ray tube 110.

[0120] Also, the user may manually rotate the second X-ray tube 110 and then manually rotate the grid. [Explanation of symbols]

[0121] 1 X-ray equipment 2 X-ray equipment 10 Stand 20 Support arm 30 Support Frame 40 Tabletop 50 pillars 51 First slide mechanism 52 Second slide mechanism 53 First rotating mechanism 60 1st X-ray tube 61 Axis 70 X-ray detector 90 1st X-ray support arm 101 Subject 110 2nd X-ray tube 111 Circular Orbit 120 1st support part 130 Second support part 131 Arm 132 Support shaft 133 Rotation Mechanism 134 Telescopic mechanism 140 Arithmetic section 141 X-ray image generation section 142 Feature Part Extraction Unit 143 3D position calculation section 144 3D image acquisition unit 145 2D Projection Image Creation Unit 146 Image Alignment Unit 150 Calculation control unit 151 Drive control unit 152 Output control section 153 High Voltage Generator 154 Data Collection Department 160 Display section 170 Medical Image Server 223 Lifting mechanism 224 Moving mechanism 701 1st X-ray image 702 3D Images 703 Calculated projection image

Claims

1. the patient table includes a tabletop on which a patient is placed, a first X-ray tube which irradiates the patient with X-rays, a first support section which supports the first X-ray tube, a second X-ray tube which irradiates the patient with X-rays, a second support section which supports the second X-ray tube, an X-ray detector which detects X-rays which are irradiated by the first X-ray tube and the second X-ray tube and which have passed through the patient, and a calculation section; the calculation unit obtains a first X-ray image from an output of the X-ray detector detecting the X-rays irradiated by the first X-ray tube, obtains a second X-ray image from an output of the X-ray detector detecting the X-rays irradiated by the second X-ray tube, and calculates a three-dimensional position of an image of a predetermined characteristic portion using a position of an image of the predetermined characteristic portion included in the first X-ray image and a position of the image of the predetermined characteristic portion included in the second X-ray image; the second support unit includes a mechanism for rotatably supporting the second X-ray tube along a circular orbit centered on an axis connecting the first X-ray tube and the tabletop.

1. An X-ray imaging apparatus comprising:

2. 2. The X-ray imaging apparatus according to claim 1, The second support portion includes an arm having a base portion and a tip portion, a support shaft, and a rotation mechanism, the support shaft is provided at a position on the first support portion to support the first X-ray tube, the base of the arm is supported by the support shaft, The second X-ray tube is provided at a tip of the arm, The support shaft is provided with a rotation mechanism that rotates the base of the arm around the support shaft.

1. An X-ray imaging apparatus comprising:

3. 2. The X-ray imaging apparatus according to claim 1, The second support portion is provided with a drive portion that changes the position of the second X-ray tube along the circular orbit.

1. An X-ray imaging apparatus comprising:

4. 2. The X-ray imaging apparatus according to claim 1, The second support portion includes a mechanism for changing the radius of the circular orbit.

1. An X-ray imaging apparatus comprising:

5. 3. The X-ray imaging apparatus according to claim 2, An X-ray imaging apparatus, characterized in that the arm is provided with an extension / contraction mechanism that changes the radius of the circular orbit by extending and contracting the arm in an axial direction.

6. 2. The X-ray imaging apparatus according to claim 1, further comprising: a third X-ray tube for irradiating the subject with X-rays; and a third support section for supporting the third X-ray tube, the third support portion supports the third X-ray tube rotatably along a circular orbit centered on an axis passing through the first X-ray tube.

1. An X-ray imaging apparatus comprising:

7. 2. The X-ray imaging apparatus according to claim 1, An X-ray imaging apparatus, wherein a maximum irradiation area of ​​X-rays from the second X-ray tube onto the X-ray detector is smaller than a maximum irradiation area of ​​X-rays from the first X-ray tube onto the X-ray detector.

8. 2. The X-ray imaging apparatus according to claim 1, An X-ray imaging apparatus, wherein a maximum output of X-rays from the second X-ray tube is smaller than a maximum output of X-rays from the first X-ray tube.

9. 2. The X-ray imaging apparatus according to claim 1, An X-ray imaging device characterized in that the calculation unit includes an extraction unit that extracts and detects images of a specified characteristic portion included in the first X-ray image and the second X-ray image, and a three-dimensional position calculation unit that calculates the three-dimensional position of the characteristic portion using the positions of the images of the characteristic portion included in the first X-ray image and the second X-ray image.

10. 2. The X-ray imaging apparatus according to claim 1, the calculation unit detects the positions of a predetermined target and the spine included in the first X-ray image or the second X-ray image, or receives the positions of the target and the spine from a user, and, if the positions of the target and the spine overlap, displays on a display unit a message prompting the user to place the second X-ray tube at a position shifted laterally from a central axis of the subject.

11. 4. The X-ray imaging apparatus according to claim 3, The calculation unit drives the drive unit to move the second X-ray tube in accordance with the position of the image of the characteristic portion included in the second X-ray image, thereby causing the field of view of the second X-ray image to follow the movement of the characteristic portion.

12. 2. The X-ray imaging apparatus according to claim 1, further comprising: a grid having a plurality of parallel ridges arranged on the X-ray detector; and a rotation drive unit that rotates the grid within a principal plane, The X-ray imaging apparatus according to claim 1, wherein the rotation drive unit rotates the grid in accordance with a position of the second X-ray tube on the circular orbit.

13. a first X-ray tube is disposed at a position where a target portion of a subject placed on a tabletop is irradiated with X-rays, and a second X-ray tube is rotated along a circular orbit centered on an axis connecting the first X-ray tube and the tabletop to dispose the second X-ray tube; irradiating an object with X-rays from a first X-ray tube, and detecting the X-rays that have passed through the object with an X-ray detector to obtain a first X-ray image; irradiating an object with X-rays from a second X-ray tube, and detecting the X-rays that have passed through the object with an X-ray detector to obtain a second X-ray image; Calculating a three-dimensional position of the image of a predetermined characteristic portion using a position of the image of the predetermined characteristic portion included in the first X-ray image and a position of the image of the predetermined characteristic portion included in the second X-ray image.

13. An X-ray imaging method comprising:

Images