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, and is equipped with a calibration function.SOLUTION: A calibration member supported by any one of a first pillar, a second pillar, and a top plate is disposed at a predetermined calibration position in a space irradiated with an X-ray from a first X-ray tube and a second X-ray tube. A subject placed on the top plate is irradiated with an X-ray from the first X-ray tube supported by the first pillar, the X-ray passing through the subject is detected by an X-ray detector disposed in the top plate, and a first X-ray image is acquired. The subject is irradiated with an X-ray from the second X-ray tube supported by the second pillar at a position deviated from an optical axis of the first X-ray tube, the X-ray passing through the subject is detected by the X-ray detector, and a second X-ray image is acquired. A three-dimensional position of the calibration member is calculated using the position of an image of the calibration member included in the first X-ray image and the position of an image of the calibration member included in the second X-ray image, and an amount of deviation from the calibration position is acquired.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 x N X-ray sources and a flat panel detector consisting of K x 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 making it possible to obtain any multi-layer tomographic 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] The 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 requires a large number of X-ray sources, resulting in a complex configuration and a large device.

[0007] In addition, in order to accurately detect the position coordinates of the treatment tool during surgery in a predetermined three-dimensional coordinate system such as a real space coordinate system or an apparatus coordinate system set in the apparatus, it is necessary to place a predetermined point of the phantom at a specific point A whose position coordinates are known in advance, detect the three-dimensional position coordinates of the specific point of the phantom by an X-ray imaging apparatus, and calibrate the position detection function of the X-ray imaging apparatus so that the position coordinates of the point A known in advance and the three-dimensional position coordinates detected by the X-ray imaging apparatus match. However, it is not easy to obtain the position coordinates of the specific point A in advance and place the phantom at that position. For example, in order to detect the position of the specific point A in the real space in advance, a separate three-dimensional position detection device such as an optical or magnetic three-dimensional position detection device is required. In order to point out the specific point A in the three-dimensional space to a user or a serviceman in the apparatus coordinate system of the X-ray imaging apparatus, a separate optical device or the like that points out the specific point A, which is a point in the three-dimensional space, is required. In addition, it is not an easy task to accurately align and install the specific point of the phantom at the specific point A in the three-dimensional space.

[0008] An object of the present invention is to provide an X-ray imaging apparatus that has a minimum necessary and compact configuration, is capable of grasping the three-dimensional position of a treatment tool in real time during surgery, and has a calibration function. [Means for solving the problem]

[0009] In order to achieve the above object, 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 column that supports the first X-ray tube, a second X-ray tube that irradiates the subject with X-rays, a second support column 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, a calculation unit, and a calibration member. The second X-ray tube is disposed at a position shifted from the optical axis of the first X-ray tube by the second support column. The calculation unit obtains a first X-ray image from the output of the X-ray detector detecting the X-rays irradiated by the first X-ray tube, obtains a second X-ray image from the output of the X-ray detector detecting the X-rays irradiated by the second X-ray tube, and calculates a three-dimensional position of a predetermined characteristic portion using the position of an image of a predetermined characteristic portion included in the first X-ray image and the position of an image of the characteristic portion included in the second X-ray image. The calibration member is supported by one of the first support column, the second support column, and the top plate at a predetermined calibration position in a space where X-rays are irradiated from the first X-ray tube and the second X-ray tube. Effect of the Invention

[0010] The X-ray imaging device of the present invention can detect the three-dimensional position of a treatment tool in real time during surgery without rotating the support of the X-ray tube, and since it is equipped with a calibration function, it can easily calibrate the three-dimensional position and accurately detect the three-dimensional position. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1A is a diagram showing a schematic configuration of the X-ray imaging device 1 according to an embodiment of the present invention, when viewed from the side, with the second X-ray tube 110 and the calibration member 180 stored therein; FIG. 1B is a diagram showing a schematic configuration of the X-ray imaging device 1 according to an embodiment of the present invention, when viewed from the front. [Diagram 2] FIG. 2A is a diagram showing a schematic configuration of the X-ray imaging device 1 according to an embodiment of the present invention, when viewed from the side, with the second X-ray tube 110 and the calibration member 180 protruding, and FIG. 2B is a diagram showing a schematic configuration when viewed from the front. [Diagram 3] FIG. 1A is a diagram showing a schematic configuration of the X-ray imaging device 1 according to an embodiment of the present invention when viewed from the side with the second X-ray tube 110 protruding and the calibration member 180 stored, and FIG. 1B is a diagram showing a schematic configuration when viewed from the front. [Figure 4] 1 is a block diagram showing the configuration of a main part of an X-ray imaging apparatus 1 according to an embodiment. [Diagram 5] 1 is a perspective view of an X-ray imaging device 1 according to an embodiment. [Figure 6] (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 the embodiment, 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. [Figure 7] FIG. 4 is a flowchart showing the operation of the X-ray imaging apparatus 1 in the embodiment in a calibration mode. [Figure 8] FIG. 1A is a sequence diagram showing the timing of tube current supply to the first X-ray tube, tube current supply to the second X-ray tube, and data collection in the calibration mode of the X-ray imaging device 1 of the embodiment; FIG. 1B is a sequence diagram showing the timing of tube current supply to the first X-ray tube, tube current supply to the second X-ray tube, and data collection in the imaging mode of the X-ray imaging device 1 of the embodiment. [Figure 9] 2(a) to 2(h) are diagrams showing example images captured by the X-ray imaging device 1 of the first embodiment. [Figure 10] FIG. 4 is a flowchart showing the operation of the X-ray imaging device 1 in the embodiment in an imaging mode. [Figure 11] 3A and 3B are diagrams showing examples of screens displayed on a display unit of the X-ray imaging device 1 according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0013] The configuration of an X-ray imaging device 1 according to the embodiment will be described.

[0014] 1 to 3 are diagrams showing a schematic configuration of the X-ray imaging device 1 as seen from the side and the front, respectively, with Figs. 1(a) and (b) showing a state in which the second X-ray tube 110 and the calibration member 180 are stored, Figs. 2(a) and (b) showing a state in which the second X-ray tube 110 and the calibration member 180 are protruding, and Figs. 3(a) and (b) showing a state in which the second X-ray tube 110 is protruding and the calibration member 180 is stored. Fig. 4 is a block diagram showing the configuration of the main parts of the X-ray imaging device 1.

[0015] As shown in Figures 1 to 3, the X-ray imaging device 1 is configured to include a tabletop 40 on which a subject 101 is placed, a first X-ray tube 60, a second X-ray tube 110, a first support column 50, a second support column 130, an X-ray detector 70, a calibration member 180, and an arithmetic and control unit 150.

[0016] The first X-ray tube 60 and the second X-ray tube 110 irradiate X-rays onto the subject 101. The first support column 50 supports the first X-ray tube 60. The second support column 130 supports the second X-ray tube. The X-ray detector 70 detects the X-rays irradiated by the first X-ray tube 60 and the second X-ray tube 110 and passing through the subject.

[0017] The calibration member 180 is supported by either the first support column 50, the second support column 130 or the tabletop 40, and is supported at a predetermined calibration position 111 in the space where X-rays are irradiated from the first X-ray tube 60 and the second X-ray tube 110.

[0018] The calibration member 180 is preferably supported movably on any one of the first support column 50, the second support column 130, and the top board 40. When the calibration member 180 protrudes, it is disposed at the calibration position 111, and when it does not protrude, it is disposed at a position outside the space where X-rays are irradiated from the first X-ray tube 60 and the second X-ray tube 110. In this way, the calibration member 180 is protruded and disposed at the calibration position 111 in the space where X-rays are irradiated only when the position detection function of the X-ray imaging device 1 is calibrated, and when the calibration is completed, it is returned to the non-protruding state and stored so as not to interfere with imaging.

[0019] The calibration member 180 is an object that absorbs X-rays, such as a metal sphere.

[0020] Here, an example in which the calibration member 180 is supported by the first support 50 will be described. Specifically, the first support 50 includes a calibration pivot support 190 arranged along the side of the first support 50. The central axis of the calibration pivot support 190 is parallel to the central axis of the first support 50 in a non-rotating state. The calibration member 180 is fixed to the tip of the calibration pivot support 190. The base 191 of the calibration pivot support 190 is rotatably fixed to the first support 50. Thereby, when performing calibration, the calibration member 180 can be placed at the calibration position 111 by rotating the calibration pivot support 190 90° around the base 191. Moreover, when the calibration is completed, the calibration pivot support 190 can be returned to its original position and the calibration member 180 can be stored in the first support 50.

[0021] A driving unit 192 such as a motor that rotates the calibration pivot column 190 to a predetermined angle (here, 90°) around the base 191 may be disposed on the first support column 50, and the calibration pivot column 190 may be rotated by the driving unit 192. Alternatively, the calibration pivot column 190 may be configured to be rotated manually. In the case of manual rotation, it is preferable to provide a stopper 193 that stops and supports the calibration pivot column 190 at a predetermined rotation angle (90°) relative to the first support column 50 (see FIGS. 2(a) and (b)).

[0022] The first support 50 also includes a second X-ray tube rotating support 130 as a second support 130 arranged along a side surface of the first support 50. (Hereinafter, also referred to as the second X-ray tube rotating support 130.) The second X-ray tube 110 is supported at the tip of the second X-ray tube rotating support 130. A base 131 of the second X-ray tube rotating support 130 is rotatably fixed to the first support 50. The second X-ray tube rotating support 130 rotates around the base 131 of the second X-ray tube rotating support 130, thereby allowing the second X-ray tube 110 to be positioned at a position where it irradiates the X-ray detector 70 with X-rays. The second X-ray tube 110 is arranged at a position shifted from the optical axis 61 of the first X-ray tube 60 by the second X-ray tube rotating support (second support) 130. Being positioned away from the optical axis 61 of the first X-ray tube 60 means that the second X-ray tube 110 is positioned outside the irradiation area of ​​the first X-ray tube 60, and also includes cases where the optical axis of the second X-ray tube 110 has a different angle of incidence on the subject 101 than the optical axis 61 of the first X-ray tube 60.

[0023] Moreover, by changing the rotation angle of the second X-ray tube rotation support 130, the relative position of the second X-ray tube 110 with respect to the first X-ray tube 60 can be changed.

[0024] One of the calibration pivot column 190 and the second X-ray tube pivot column 130 may be configured to have an opening 194 along the central axis, and the other may be disposed within the opening 194. With this configuration, the central axes of the calibration pivot column 190 and the second X-ray tube pivot column 130 can be aligned with each other when the calibration pivot column 190 and the second X-ray tube pivot column 130 are not rotating. This is preferable because it allows the second X-ray tube 110 and the calibration member 180 to be disposed on the central axes of the calibration pivot column 190 and the second X-ray tube pivot column 130.

[0025] Here, as shown in FIG. 1(b), an opening 194 is provided along the central axis of the calibration pivot support 190, and the second support 130 is disposed within the opening 194.

[0026] A drive unit such as a motor that rotates the second X-ray tube rotating column 130 to a predetermined angle (e.g., 45°) about the base 131 may be disposed inside the first column 50, and the second X-ray tube rotating column 130 may be rotated by the drive unit. Alternatively, the second X-ray tube rotating column 130 may be configured to be rotated manually. In the case of manual rotation, it is preferable to provide a stopper that stops and supports the second X-ray tube rotating column 130 at a predetermined rotation angle (e.g., 45°) relative to the first column 50.

[0027] The central axis of rotation of the base 191 of the calibration rotating column 190 may be configured to coincide with the central axis of rotation of the base 131 of the second X-ray tube rotating column 130. When the central axis of rotation of the base 191 of the calibration rotating column 190 coincides with the central axis of rotation of the base 131 of the second X-ray tube rotating column 130, the drive unit 192 and the stopper 193 of the calibration rotating column 190 can be used as a drive unit that rotates the second X-ray tube rotating column 130 and a stopper that stops it.

[0028] The configuration of other parts of the X-ray imaging device 1 will be further described with reference to Figures 1 to 3 and Figure 5. Figure 5 is a perspective view of the X-ray imaging device 1.

[0029] The first X-ray tube 60 is attached to the tip of a first X-ray support arm 90 supported on the upper end of a first support column 50. The lower end of the first support column 50 is supported by a column support arm 20 provided on the stand 10.

[0030] The position at which the second X-ray tube 110 is positioned by the second X-ray tube rotating support (second support) 130 when irradiating X-rays is a position offset from the optical axis 61 of the first X-ray tube 60 and closer to the subject 101 than the first X-ray tube 60.

[0031] Furthermore, 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 second X-ray tube onto the X-ray detector.

[0032] 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 .

[0033] The first X-ray support arm 90 supporting the first X-ray tube 60 is provided with a second slide mechanism 52 for moving the position of the first X-ray tube 60 in the width direction (A5 direction = x direction) of the tabletop 40 relative to the first support column 50. Furthermore, a first rotation mechanism for rotating (A6 direction) the first X-ray tube 60 at the tip of the first X-ray support arm 90 about an axis parallel to the major axis (y axis) of the tabletop 40 is disposed at the connection between the first X-ray tube 60 and the first X-ray support arm 90.

[0034] Further, a first slide mechanism 51 is provided between the lower end of the first support column 50 and the support column support arm 20, for moving the lower end of the first support column 50 in the width direction (f direction = x direction) of the tabletop 40 relative to the stand 10. This allows the first support column 50 and the second support column 130 to move together in the x direction.

[0035] The column support arm 20 is equipped with a support frame 30 that supports not only the first column 50 but also the tabletop 40. The stand 10 has a built-in drive mechanism (not shown) that moves the column support arm 20 up and down (A1 direction=z axis). This allows the tabletop 40 and the first X-ray tube 60 to be raised and lowered while maintaining the positional relationship between the first X-ray tube 60 and the tabletop 40.

[0036] Further, a moving mechanism (not shown) for moving the first support column 50 in the longitudinal direction (A3 direction=y-axis) of the tabletop 40 is built into the column support arm 20 of the stand 10. 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.

[0037] The stand 10 is also provided with a lifting / tilting mechanism (not shown) that rotates (in the direction 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 / tilted while maintaining the positional relationship between the first X-ray tube 60 and the top board 40.

[0038] Furthermore, the column support arm 20 is provided with a tilting mechanism 222 at the connection portion with the first column 50, which rotates (in the A2 direction) the first column 50 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 column 50 to be tilted relative to the tabletop 40 around the x-axis as the center of rotation.

[0039] Furthermore, within the top board 40, an X-ray detector drive mechanism 41 is provided which moves the X-ray detector 70 relative to the top board 40 in the long axis direction (A8 direction) and short axis direction (A7 direction) of the top board 40.

[0040] The above-mentioned drive mechanisms, such as the first slide mechanism 51 and the X-ray detector drive mechanism 41, may have any configuration. As an example, they may be configured to include a rack arranged along the movement direction, a pinion that meshes with the rack, and a motor that rotates the pinion.

[0041] The calculation control unit 150 includes a calibration control unit 155, a drive control unit 151, an output control unit 152, a high voltage generator 153, a data collection unit 154, and a calculation unit 140. The drive control unit 151 controls the operation of a drive unit 192 such as a motor that rotates the calibration rotating column 190 and the second X-ray tube rotating column 130, and each drive mechanism such as the first slide mechanism 51 and the X-ray detector drive mechanism 41.

[0042] 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 voltage value and current value set respectively, 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 output of the first X-ray tube 60 and the second X-ray tube 110 individually.

[0043] The data collection unit 154 collects signals output by the X-ray detection elements, which are two-dimensionally arranged in the X-ray detector 70, upon receiving X-ray irradiation. 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.

[0044] The calculation unit 140 includes an X-ray image generation unit 141 , a characteristic portion extraction unit 142 , a three-dimensional position calculation unit 143 , and a correction unit 147 .

[0045] The X-ray image generating 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 collecting unit 154, and generates a first X-ray image (see FIG. 5(b)). Also, the X-ray image generating 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 collecting unit 154, and generates a second X-ray image (see FIG. 5(c)).

[0046] 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 the characteristic part included in the second X-ray image by a known method. The characteristic part during surgery is, for example, the tip of a treatment tool such as a catheter. The characteristic part during calibration is a calibration member 180.

[0047] The three-dimensional position calculation unit 143 calculates the three-dimensional position of the image of the specified characteristic part using the position of the image of the specified characteristic part included in the first X-ray image and the position of the image of the specified characteristic part included in the second X-ray image.

[0048] A specific example of a method for calculating a characteristic portion will be described. As shown in FIG. 6(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. 6(a). In reality, as shown in FIG. 6(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 can be obtained, and the midpoint u of the two points can be set as the position of the image of the characteristic portion, for example.

[0049] Points Q1 and Q2 shown in FIG. 6(c) can be determined according to the following formula 1.

[0050] 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

[0051] 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.

[0052] u=(Q1+Q2) / 2 ···(2) <Calibration mode> The operations of the calibration control unit 155 and the correction unit 147 will be described with reference to FIG. 7, FIG. 8(a) and FIGS. 9(a) to (h).

[0053] Fig. 7 is a flow chart showing the operation of the calibration mode for configuring the coordinate system of the X-ray imaging device 1. Fig. 8(a) is a timing chart showing the X-ray irradiation timing of the first X-ray tube 60 and the second X-ray tube 110 in the calibration mode, and the data collection timing of the X-ray detector 70. Figs. 9(a) to (h) show example images.

[0054] (Step 701) When an instruction to start the calibration mode is given by the operator, the calibration control unit 155 drives the drive unit 192 to rotate the calibration rotation support 190 by 90° and rotate the second X-ray tube rotation support 130 by a predetermined angle (for example, 45°). As a result, the calibration rotation support 190 is placed at a predetermined calibration position 111. The calibration control unit 155 also controls each drive mechanism to place the first X-ray tube 60 and the second X-ray tube 110 at their respective predetermined calibration positions.

[0055] (Step 702) As shown in FIG. 8(a), first, the output control unit 152 supplies a tube current and a tube voltage set by an operator to the first X-ray tube 60, thereby irradiating X-rays from the first X-ray tube 60 to the subject 101 and performing X-ray imaging.

[0056] (Step 703) The X-ray image generating unit 141 collects data of X-rays detected by the X-ray detector 70 using the data collecting unit 154. As a result, 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 (FIG. 9(a)).

[0057] (Step 704) The characteristic portion extraction unit 142 processes the first X-ray image generated in step 703 and extracts the calibration member 180 in the first X-ray image.

[0058] (Step 705) The three-dimensional position calculation unit 143 calculates the position D1 on the X-ray detector 70 onto which the calibrating member 180 is projected, based on the position of the calibrating member 180 in the first X-ray image.

[0059] (Step 706) The three-dimensional position calculation unit 143 calculates a straight line L1 that connects two points: the position D1 of the calibration member 180 on the X-ray detector 70 and the position S1 of the first X-ray tube 60.

[0060] (Step 707) Next, the output control unit 152 supplies a tube current and a tube voltage set by the operator to the second X-ray tube 110 as shown in FIG. 8(a), thereby irradiating X-rays from the second X-ray tube 110 to the subject 101 and performing X-ray imaging.

[0061] (Step 708) The X-ray image generating unit 141 collects data of the X-rays detected by the X-ray detector 70 using the data collecting unit 154. As a result, 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 (FIG. 9(e)).

[0062] (Step 709) The feature extraction unit 142 processes the second X-ray image generated in step 708 to extract the calibration member 180 in the second X-ray image.

[0063] (Step 710) The three-dimensional position calculation unit 143 calculates the position D2 on the X-ray detector 70 where the calibrating member 180 is projected, based on the position of the calibrating member 180 in the second X-ray image.

[0064] (Step 711) The three-dimensional position calculation unit 143 calculates a straight line L2 that connects two points, that is, the position D2 of the calibration member 180 on the X-ray detector 70 and the position S2 of the second X-ray tube 110.

[0065] (Step 712) The three-dimensional position calculation unit 143 calculates the three-dimensional position coordinates of the calibration member 180 from the positional relationship between the two straight lines L1 and L2 using the above-mentioned formulas 1 and 2.

[0066] (Step 713) The calibration control unit 155 calculates the difference (amount of positional deviation) between the position coordinates of the calibration member 180 calculated in step 712 and the position coordinates of the known calibration position 111. The calibration control unit 155 displays on the display unit 160 an image that allows the amount of deviation to be grasped.

[0067] As an example of a display screen, the first X-ray image (FIG. 9(a)) and the second X-ray image (FIG. 9(e)) generated in steps 703 and 708, respectively, can be superimposed with images (e.g., FIG. 9(b) and FIG. 9(f)) showing the position of the known calibration position 111 on the first X-ray image and the position of the second X-ray image, respectively, with marks.

[0068] As a result, when the position coordinates of the calibration member 180 and the position coordinates of the known calibration position 111 match, the position of the image of the calibration member 180 in the first X-ray image and the second X-ray image and the mark for the calibration position (here, a cross) are displayed overlapping (FIGS. 9(c) and (g)). On the other hand, when the position coordinates of the calibration member 180 are deviated from the position coordinates of the known calibration position 111, the position of the image of the calibration member 180 in the first X-ray image and the second X-ray image and the mark for the calibration position are displayed misaligned (FIGS. 9(d) and (h)). This allows a user looking at the display unit 160 to easily grasp the amount of positional deviation.

[0069] (Step 714) The calibration control unit 155 calculates the direction and amount of movement of the position of the X-ray detector 70 within the main plane of the tabletop 40 using a predetermined formula, table, or the like according to the amount of positional deviation and the direction of the deviation so as to cancel the amount of positional deviation calculated in step 714. The calibration control unit 155 instructs the X-ray detector driving mechanism 41 to move the X-ray detector 70 by the calculated amount of movement in the calculated direction of movement.

[0070] The X-ray detector driving mechanism 41 adjusts the position of the X-ray detector 70 according to the instruction and performs calibration.

[0071] In this way, by executing the calibration mode, the X-ray imaging device 1 can automatically place the calibration member 180 at the predetermined calibration position 111, detect the three-dimensional position of the calibration member 180, detect the amount of positional deviation from the three-dimensional position coordinates of the calibration position 111, and automatically perform calibration to cancel the amount of positional deviation. Therefore, the three-dimensional position detected by the X-ray imaging device 1 can be easily calibrated, and the three-dimensional position coordinates of the characteristic site detected in the imaging mode can be accurately detected.

[0072] In the flow of FIG. 7, the position of the X-ray detector 70 is adjusted by the X-ray detector driving mechanism 41 in step 714, but the calibration method is not limited to this method.

[0073] For example, instead of adjusting the position of the X-ray detector 70 in step 714, a correction table for correcting the positional deviation of the characteristic portion detected in the imaging mode may be created using the amount of positional deviation calculated in step 713. Alternatively, an appropriate correction table may be selected from multiple types of correction tables obtained in advance according to the amount of positional deviation calculated.

[0074] Also, in step 714, the user may manually adjust the position of the X-ray detector 70 instead of the X-ray detector driving mechanism 41.

[0075] <Shooting mode> Next, the operation of each part in the imaging mode of the X-ray imaging device 1 will be described with reference to Figures 6(a) to (d), 8(b) and 10. Here, the operation of the imaging mode in the case where a correction table is generated in step 714 when the calibration mode is executed will be described.

[0076] Fig. 6(a) to (d) are diagrams for explaining the operation of calculating a three-dimensional position. Fig. 8(b) is a timing chart showing the X-ray irradiation timing of the first X-ray tube 60 and the second X-ray tube 110 in the imaging mode and the data collection timing of the X-ray detector 70. Fig. 10 is a flowchart showing the operation in the imaging mode.

[0077] During surgery, the X-ray imaging device 1 performs fluoroscopic imaging from the first X-ray tube 60 while performing imaging with the second X-ray tube 110 at a predetermined timing, and can grasp the three-dimensional position of the characteristic part of the treatment tool in real time. Since there is no need to rotate the X-ray tube and the X-ray detector, the surgeon does not need to retreat, and the surgeon does not need to stop performing the procedure such as inserting the treatment tool.

[0078] (Step 601) When an instruction to start imaging is given by the operator, X-rays are irradiated from the first X-ray tube 60 to the subject 101, and X-ray imaging is started.

[0079] Specifically, the drive control unit 151 controls the operation of each drive mechanism according to an instruction from the operator, and places the first X-ray tube 60 at a position desired by the operator. The output control unit 152 supplies the tube current and tube voltage set by the operator to the first X-ray tube 60 for a predetermined time, and irradiates X-rays.

[0080] (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 .

[0081] 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 a predetermined frame rate, as shown in FIG. 8(b).

[0082] 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. 6(b)). The X-ray image generating unit 141 displays the first X-ray image on the display unit 160 as shown in FIG. 6(b).

[0083] The operator inserts a treatment tool (catheter or the like) into the subject 101 while viewing the first X-ray image on the display unit 160.

[0084] (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.

[0085] (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 (FIG. 6(a)).

[0086] (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.

[0087] (Step 606) At the timing when the X-ray irradiation from the first X-ray tube 60 is completed, the second X-ray tube 110 irradiates the subject 101 with X-rays as shown in FIG. 8(b) to perform X-ray imaging.

[0088] Specifically, the drive control unit 151 controls the operation of each of the drive mechanisms 121-123 in accordance with an instruction from the operator, and places the second X-ray tube 110 at a position desired by the operator. The output control unit 152 supplies the tube current and tube voltage set by the operator to the second X-ray tube 110 for a predetermined period of time, thereby irradiating X-rays.

[0089] (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 .

[0090] Specifically, X-rays that are irradiated from the second X-ray tube 110 and pass 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 .

[0091] 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. 6(c)).

[0092] 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.

[0093] (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.

[0094] (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.

[0095] (Step 610) The three-dimensional position calculation unit 143 calculates a straight line L2 that connects two points, 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.

[0096] (Step 611) The three-dimensional position calculation section 143 calculates the three-dimensional position coordinates of the characteristic portion of the treatment tool from the positional relationship between the two straight lines L1 and L2 using the above-mentioned formulas 1 and 2 (FIG. 6(d)).

[0097] (Step 612) The correction unit 147 receives the correction table from the calibration control unit 155, calculates a correction amount for correcting the three-dimensional position coordinates of the characteristic part of the treatment tool calculated in step 611 based on the correction table, and corrects the three-dimensional position coordinates by adding the correction amount to the three-dimensional position coordinates.

[0098] (Step 613) The three-dimensional position calculation unit 143 displays the three-dimensional position of the characteristic part of the treatment tool after correction by the correction unit 147 on the display unit 160 alongside the first X-ray image 701, for example, as in the example screen of Fig. 11. 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.

[0099] (Step 614) 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 in steps 606 to 610 at regular time intervals as shown in Fig. 8(b), 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.

[0100] As described above, according to this embodiment, since imaging can be performed by the second X-ray tube 110 while imaging is performed by the first X-ray tube 60 during surgery, the three-dimensional position of the characteristic part of the treatment tool can be detected in real time. Moreover, since the three-dimensional position of the characteristic part of the treatment tool can be corrected in step 612 based on the correction table generated by the calibration control unit 155 in the calibration mode, the detection accuracy of the three-dimensional position of the characteristic part can be improved.

[0101] In the flow of Fig. 10, the three-dimensional position of the characteristic part of the treatment tool is corrected based on the correction table generated in the calibration mode in step 612, but if the position of the X-ray detector 70 has already been adjusted in the calibration mode in step 714 of Fig. 7, it is not necessary to correct the three-dimensional position of the characteristic part in the imaging mode. In this case, step 612 of the flow of Fig. 6 is not performed.

[0102] Since the second X-ray tube 110 can relatively adjust its position with respect to the subject 101 and the direction of irradiation to the subject 101 by using a driving mechanism, even if the irradiation range is narrowed, X-rays can be irradiated toward the characteristic part of the treatment tool, improving the detection accuracy of the position of the characteristic part of the treatment tool.

[0103] Furthermore, since the distance between the second X-ray tube 110 and the detector 70 can be adjusted by the rotation angle, the second X-ray tube 110 can be brought closer to the subject 101, and a small X-ray tube with low output and narrow irradiation range can be used as the second X-ray tube 110. This allows the first X-ray tube 60 and the second X-ray tube 110 to perform imaging in parallel in real time without the second X-ray tube 110 interfering with imaging by the first X-ray tube 60.

[0104] If the position of the characteristic portion acquired in time series in step 611 has moved, it is preferable that the drive control unit 151 operates at least one of the multiple drive mechanisms and the drive unit 192 to change at least one of the position, distance, and X-ray irradiation direction of the second X-ray tube 110 relative to the subject 101 when next executing step 606, and make the X-ray irradiation area of ​​the second X-ray tube 110 on the subject 101 follow the movement of the position of the characteristic portion. By making it follow in this way, even if the X-ray irradiation area of ​​the second X-ray tube 110 is small, the moving characteristic portion can always be included in the irradiation area. [Explanation of symbols]

[0105] 1 X-ray equipment 10 Stand 20 Support arm 30 Support Frame 40 Tabletop 41 X-ray detector drive mechanism 50 1st pillar 52 Second slide mechanism 60 1st X-ray tube 61 Optical axis 70 X-ray detector 90 1st X-ray support arm 101 Subject 110 2nd X-ray tube 111 Calibration Position 130 Second support (rotating support for second X-ray tube) 131 Base 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 147 Correction section 150 Calculation control unit 151 Drive control unit 152 Output control section 153 High Voltage Generator 154 Data Collection Department 155 Calibration Control Unit 160 Display section 180 Calibration material 190 Calibration Pole 191 Base 192 Drive unit 193 Stopper 194 Aperture 222 Tilt mechanism 701 1st X-ray image 702 3D Images

Claims

1. the apparatus includes a tabletop on which an object is placed, a first X-ray tube that irradiates the object with X-rays, a first support column that supports the first X-ray tube, a second X-ray tube that irradiates the object with X-rays, a second support column that supports the second X-ray tube, an X-ray detector that detects the X-rays irradiated by the first X-ray tube and the second X-ray tube, a calculation unit, and a calibration member; the second X-ray tube is disposed at a position offset from an optical axis of the first X-ray tube by the second support; 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 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 an image of the predetermined characteristic portion included in the second X-ray image; an X-ray imaging apparatus, characterized in that the calibration member is supported by any one of the first support column, the second support column, and the tabletop at a predetermined calibration position in a space where X-rays are irradiated from the first X-ray tube and the second X-ray tube.

2. 2. The X-ray imaging apparatus according to claim 1, wherein the calibration member is supported by any one of the first support column, the second support column, or the tabletop in a retractable manner, and when protruding, the calibration member is disposed at the calibration position, and when not protruding, the calibration member is disposed at a position outside a space into which X-rays are irradiated from the first X-ray tube and the second X-ray tube.

3. 3. The X-ray imaging apparatus according to claim 2, wherein the calibration member is an object that absorbs X-rays, the first support includes a calibration pivot post disposed along a side of the first support; the calibration member is fixed to the tip of the calibration pivot support, the base of the calibration pivot support is rotatably fixed to the first support, and the calibration member is positioned at the calibration position by the calibration pivot support rotating around the base.

4. 4. The X-ray imaging apparatus according to claim 3, wherein the first support column is provided with a drive section for rotating the calibration pivot support column around the base section to a predetermined angle.

5. 4. The X-ray imaging apparatus according to claim 3, wherein the first support column is provided with a stopper that stops and supports the calibration rotating support column at a predetermined rotation angle relative to the first support column.

6. 4. An X-ray imaging apparatus according to claim 3, wherein a central axis of said calibration pivot support column is parallel to a central axis of said first support column when said calibration support column is not pivoted.

7. 4. The X-ray imaging apparatus according to claim 3, wherein the first support column includes a second X-ray tube rotating column disposed along a side surface of the first support column, an X-ray imaging device comprising: a second X-ray tube supported at a tip of the rotating support for the second X-ray tube; a base of the rotating support for the second X-ray tube being rotatably fixed to the first support; and the rotating support for the second X-ray tube rotating around the base of the rotating support for the second X-ray tube, thereby positioning the second X-ray tube in a position where it irradiates X-rays to the X-ray detector.

8. 8. The X-ray imaging apparatus according to claim 7, wherein one of the calibration pivot support and the second X-ray tube pivot support has an opening along a central axis, and the other is disposed within the opening; The X-ray imaging apparatus according to claim 1, wherein the calibration pivot column and the second X-ray tube pivot column have the same central axis when they are not pivoting.

9. 9. An X-ray imaging apparatus according to claim 8, wherein a central axis of rotation of the base of the calibration pivot column coincides with a central axis of rotation of the base of the second X-ray tube pivot column.

10. 8. The X-ray imaging apparatus according to claim 7, wherein the first support is provided with a second X-ray tube drive unit that rotates the second X-ray tube rotating support to a predetermined angle around a base of the second X-ray tube rotating support.

11. 8. The X-ray imaging apparatus according to claim 7, wherein the first support column is provided with a second X-ray tube stopper that stops and supports the second X-ray tube rotating support column at a predetermined rotation angle relative to the first support column.

12. 2. The X-ray imaging apparatus according to claim 1, further comprising: a calibration control unit; and an X-ray detector driving unit that moves the position of the X-ray detector within a main plane of the tabletop; the calibration control unit places the calibration member at the calibration position, causes the calculation unit to calculate the position of the calibration member, determines an amount of positional deviation between the calculated calibration member and a predetermined position, and causes the X-ray detector drive unit to shift the position of the X-ray detector in accordance with the determined amount of positional deviation.

13. 2. The X-ray imaging apparatus according to claim 1, further comprising: a calibration control unit; and a correction unit that corrects the three-dimensional position of the characteristic portion calculated by the calculation unit, the calibration control unit disposes the calibration member at the calibration position, causes the calculation unit to calculate the position of the calibration member, and determines an amount of positional deviation between the calculated calibration member and a predetermined position; The correction unit corrects the three-dimensional position of the characteristic portion calculated by the calculation unit in accordance with the amount of positional deviation thus determined.

14. 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.

15. 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.

16. 16. The X-ray imaging apparatus according to claim 15, an output control unit for controlling outputs of the first X-ray tube and the second X-ray tube; The X-ray imaging apparatus according to claim 1, wherein the output control unit is capable of individually controlling the outputs of the first X-ray tube and the second X-ray tube.

17. a calibration member supported by any one of the first support column, the second support column, and the tabletop is disposed at a predetermined calibration position in a space where the X-rays are irradiated from the first X-ray tube and the second X-ray tube; irradiating the space with X-rays from a first X-ray tube supported by the first support column, and detecting the X-rays that have passed through the space with an X-ray detector to obtain a first X-ray image; irradiating the space with X-rays from a second X-ray tube supported by the second column at a position shifted from an optical axis of the first X-ray tube, and detecting the X-rays that have passed through the space with the X-ray detector to obtain a second X-ray image; A three-dimensional position of the calibration member is calculated using a position of the image of the calibration member included in the first X-ray image and a position of the image of the calibration member included in the second X-ray image, and a deviation amount from the calibration position is obtained.

13. An X-ray imaging method comprising:

Images