JP6129593B2 - IVR-CT equipment - Google Patents

Description

  Embodiments described herein relate generally to an IVR-CT apparatus.

  Conventionally, there is an IVR (Interventional Radiology) -CT apparatus in which an X-ray CT (Computed Tomography) apparatus and an X-ray diagnostic apparatus are combined. In the IVR-CT apparatus, CT examination using an X-ray CT apparatus and treatment using an X-ray diagnostic apparatus are used in combination. For example, an operator such as a doctor (hereinafter referred to as an “operator”) refers to an X-ray CT image (tomographic image) of a subject imaged by an X-ray CT apparatus, and a site requiring treatment such as stenosis. To identify. Then, for example, the operator performs an intravascular intervention treatment using a catheter while referring to an X-ray image (fluoroscopic image) of a stenosis site imaged by an X-ray diagnostic apparatus.

JP-A-9-276264

  The problem to be solved by the present invention is to provide an IVR-CT apparatus capable of reducing the exposure dose.

The IVR-CT apparatus of the embodiment includes a bed, a first support unit, a second support unit, a setting unit, a calculation unit, and a control unit. The subject is placed on the bed. The first support unit supports the first X-ray tube and a first X-ray detector that detects X-rays irradiated from the first X-ray tube and transmitted through the subject. . The second support unit detects a second X-ray tube and X-rays emitted from the second X-ray tube across the imaging space in which the bed is moved. The second X-ray tube and the second X-ray detector are moved on a circular orbit surrounding the imaging space by supporting the detector facing each other. The setting unit sets a region of interest on an X-ray image generated based on the X-ray detected by the first X-ray detector. The calculation unit passes through a plurality of objects at different positions in the body axis direction and the body thickness direction, which are irradiated from the first X-ray tube and projected onto the region of interest when the X-ray image is captured. The angle between the X-ray trajectory and the scanning plane of the X-rays irradiated from the second X-ray tube and orthogonal to the body axis direction is calculated. The control unit tilts the bed or the second support unit based on the angle calculated by the calculation unit such that the X-ray scanning plane overlaps the X-ray trajectory.

FIG. 1 is a diagram illustrating a configuration example of an IVR-CT apparatus according to the first embodiment. FIG. 2 is a diagram illustrating an example of X-ray image data collected by the system control apparatus according to the first embodiment. FIG. 3 is a diagram showing an example of a CT imaging region set by a conventional X-ray CT apparatus. FIG. 4 is a diagram illustrating an example of a CT imaging region set by the system control apparatus according to the first embodiment. FIG. 5 is a diagram for explaining processing executed by the calculation unit according to the first embodiment. FIG. 6 is a diagram for explaining processing executed by the movement control unit according to the first embodiment. FIG. 7 is a diagram for explaining processing executed by the movement control unit according to the first embodiment. FIG. 8A is a diagram for explaining processing executed by the correction unit according to the first embodiment. FIG. 8B is a diagram for explaining processing executed by the correction unit according to the first embodiment. FIG. 9 is a flowchart illustrating a processing procedure performed by the system control apparatus according to the first embodiment. FIG. 10 is a diagram illustrating an example when the movement control unit according to the second embodiment tilts the bed at an inclination angle. FIG. 11 is a diagram illustrating an example of an operation for reconstructing tomographic image data having no angle inclination by the correction unit according to the first embodiment.

  Hereinafter, an IVR-CT apparatus according to an embodiment will be described with reference to the drawings.

(First embodiment)
First, a configuration example of the IVR-CT apparatus 10 will be described with reference to FIG. FIG. 1 is a diagram illustrating a configuration example of an IVR-CT apparatus 10 according to the first embodiment. The IVR-CT apparatus 10 includes a monitor 20, a bed 30, a C arm holding apparatus 40, a CT apparatus gantry 60, and a system control apparatus 100. The subject P is not included in the IVR-CT apparatus 10. Further, in the following description, the C-arm holding device 40 and the system control device 100 are integrated and referred to as an X-ray diagnostic apparatus 200, and the CT apparatus gantry 60 and the system control apparatus 100 are integrated to form an X-ray CT apparatus 300. Sometimes called.

  In such an IVR-CT apparatus 10, CT examination by the X-ray CT apparatus 300 and treatment by the X-ray diagnostic apparatus 200 are used in combination. For example, an operator such as a doctor (hereinafter referred to as an “operator”) refers to an X-ray CT image (tomographic image) taken by the X-ray CT apparatus 300 to identify a site requiring treatment such as stenosis. I do. Then, for example, the operator performs an intravascular interventional treatment with a catheter while referring to an X-ray image (fluoroscopic image) of a stenosis site imaged by the X-ray diagnostic apparatus 200.

  Next, each part of the IVR-CT apparatus 10 will be described. The monitor 20 displays an X-ray image such as a fluoroscopic image taken by the X-ray diagnostic apparatus 200 or a tomographic image based on tomographic image data taken by the X-ray CT apparatus 300, for example.

  The subject P is placed on the bed 30. For example, the bed 30 includes a top plate 31 on which the subject P is placed and is movable in the vertical direction and the horizontal direction. Moreover, the bed 30 can move the top plate 31 in the longitudinal direction, or in the longitudinal direction and the lateral direction. The bed 30 moves the subject P to the imaging region of the X-ray diagnostic apparatus 200 or the imaging region of the X-ray CT apparatus 300 by moving the own apparatus or the top plate 31. In the IVR-CT apparatus 10, the bed 30 is shared by the X-ray diagnostic apparatus 200 and the X-ray CT apparatus 300.

  The C arm holding device 40 supports a C arm 41 (also referred to as a first support portion). The C arm 41 supports an X-ray tube 42 (also referred to as a first X-ray tube) and an X-ray detector 43 (also referred to as a first X-ray detector) facing each other. The X-ray tube 42 emits X-rays. The X-ray detector 43 detects X-rays irradiated from the X-ray tube 42 and transmitted through the subject P. The pair of the X-ray tube 42 and the X-ray detector 43 is configured to rotate around a geometric rotation center (hereinafter referred to as an isocenter).

  The CT apparatus gantry 60 includes a rotating frame 61 (also referred to as a second support unit) and a data collection unit 64. The rotating frame 61 detects a CT-X-ray tube 62 (also referred to as a second X-ray tube) and X-rays emitted from the CT-X-ray tube 62 across an imaging space in which the bed 30 is moved. A circular orbit centering on a rotation center (hereinafter referred to as a CT isocenter) set in the imaging space, which is supported by a CT-X-ray detector 63 (also referred to as a second X-ray detector) opposed to each other. The CT-X-ray tube 62 and the CT-X-ray detector 63 are moved above. In other words, the rotating frame 61 is an annular frame that rotates continuously at high speed, and the CT-X-ray tube 62 and the CT-X-ray detector 63 are opposed to each other with the subject P interposed therebetween. I support it. The CT apparatus gantry 60 is movable in the horizontal direction on the Z axis.

  The CT-X-ray tube 62 generates X-rays based on a predetermined tube voltage and tube current applied by a high voltage generator (not shown), and is placed on the top 31 while rotating around the subject P. This X-ray is irradiated toward the subject P to be placed.

  The CT-X-ray detector 63 detects the X-ray dose of the X-ray beam that has passed through the subject P. For example, the CT-X-ray detector 63 has a configuration of a plurality of channels and a plurality of columns of detectors in which a plurality of X-ray detection channels are arranged in a two-dimensional matrix. The detected transmitted X-ray dose data is output to the data collection unit 64.

  The data collection unit 64 collects transmission X-ray dose data detected by the CT-X-ray detector 63. The data collection unit 64 performs amplification processing, A / D (Analog to Digital) conversion processing, and the like on the collected transmitted X-ray dose data, and then outputs the data to the system control apparatus 100.

  The system control device 100 controls the bed 30, the C arm holding device 40, and the CT apparatus gantry 60 to collect X-ray image data of the subject P and tomographic image data of the subject P. For example, the system control apparatus 100 includes an operation unit 101, an X-ray image data storage unit 102, a tomogram data storage unit 103, a system control unit 104, a setting unit 105, a movement control unit 106, and an X-ray image. A data collection unit 107, a tomographic image data generation unit 108, a display control unit 109, a calculation unit 110, and a correction unit 111 are provided.

  The operation unit 101 is a control panel, a foot switch, a joystick, or the like, and receives input of various operations on the X-ray diagnostic apparatus 200 from an operator. For example, the operation unit 101 receives an operation on the bed 30 for moving the observation target in the subject P to the center of the screen from the operator. Thereby, the movement control part 106 moves the bed 30 according to an operator's operation. In addition, the operation unit 101 receives an operation for rotating the C-arm 41 from the operator. Thereby, the movement control part 106 rotates the C arm 41 according to an operator's operation. The operation unit 101 also receives an operation for moving the CT apparatus gantry 60 in the horizontal direction from the operator. Thereby, the movement control part 106 moves the CT apparatus gantry 60 in a horizontal direction according to an operator's operation.

  In addition, the operation unit 101 accepts setting of shooting conditions from the operator. For example, the operation unit 101 receives an operation for setting the coronary artery as an observation target from the operator. For example, the operation unit 101 receives information such as SID (Source-Imager Distance) and FOV (Field Of View) from the operator. Note that values such as SID and FOV may be held in advance by the X-ray diagnostic apparatus 200. The operation unit 101 receives an instruction to collect X-ray image data from the operator. The operation unit 101 receives an instruction for setting an imaging region (hereinafter referred to as a CT imaging region) by the X-ray CT apparatus and an instruction for collecting tomographic image data from the operator.

  The X-ray image data storage unit 102 stores X-ray image data and the like. The tomogram data storage unit 103 stores tomogram data and the like. The system control unit 104 performs overall control of the system control apparatus 100 based on an instruction from the operation unit 101.

  The setting unit 105 sets a region of interest on the X-ray image generated based on the X-ray detected by the X-ray detector 43. For example, when the setting unit 105 receives a setting of a predetermined region on the angio image from the operator via the operation unit 101, the setting unit 105 sets the received predetermined region as a region of interest.

  The movement control unit 106 (also referred to as a control unit) performs operation control of each unit included in the IVR-CT apparatus 10. For example, the movement control unit 106 controls the vertical movement of the bed 30 and the horizontal movement of the bed 30 based on an input signal from the operation unit 101. The movement control unit 106 controls the rotation of the C arm 41 and the like under the control of the X-ray image data collection unit 107. The movement control unit 106 controls the operation of each unit of the CT apparatus gantry 60. For example, based on the input signal from the operation unit 101, the movement control unit 106 moves the CT apparatus gantry 60 in the horizontal direction, controls the rotation operation of the rotating frame 61, controls the operation of the CT-X-ray tube 62, CT- Operation control of the X-ray detector 63, operation control of the data collection unit 64, and the like are executed.

  Upon receiving an X-ray image data collection instruction from the operator via the operation unit 101, the X-ray image data collection unit 107 controls the X-ray tube 42, the X-ray detector 43, and the movement control unit 106, Collect X-ray image data. Here, the X-ray image data collection unit 107 collects an image in which X-rays irradiated on the subject P are projected by the X-ray detector 43. The X-ray image data collection unit 107 outputs the collected X-ray image data to the display control unit 109. The X-ray image data collection unit 107 stores the collected X-ray image data in the X-ray image data storage unit 102.

  The tomographic image data generation unit 108 performs image data generation processing and various types of image processing based on the data collected by the data collection unit 64. For example, the tomogram data generation unit 108 uses the projections transmitted from the data collection unit 64 based on predetermined reconstruction parameters such as a reconstruction region size, a reconstruction matrix size, and a threshold value for extracting a region of interest. The data is reconstructed, and tomographic image data for a predetermined slice is generated. The tomographic image data generation unit 108 outputs a tomographic image based on the generated tomographic image data to the display control unit 109. The tomogram data generation unit 108 stores the projection data transmitted from the data collection unit 64 and the generated tomogram data in the tomogram data storage unit 103.

  The display control unit 109 displays the X-ray image data collected by the X-ray image data collection unit 107 on the monitor 20. In addition, the display control unit 109 causes the monitor 20 to display a tomographic image based on the tomographic image data generated by the tomographic image data generation unit 108.

  The calculation unit 110 irradiates the X-ray trajectory that has been irradiated from the X-ray tube 42 when passing through the position corresponding to the region of interest of the subject P and the X-ray irradiated from the CT-X-ray tube 62. An inclination angle that is an angle between the line and the scanning plane is calculated. Details of the calculation unit 110 will be described later.

  The correcting unit 111 corrects the distance on the tomographic image generated by the tomographic image data generating unit 108 according to the inclination angle calculated by the calculating unit 110. Details of the correction unit 111 will be described later.

  Next, X-ray image data collected by the system control apparatus 100 will be described with reference to FIG. FIG. 2 is a diagram illustrating an example of X-ray image data collected by the system control apparatus 100 according to the first embodiment. 2 shows an example in which the X-rays irradiated from the X-ray tube 42 pass through the subject P and are detected by the X-ray detector 43. . Here, the subject P is placed on the top 31 (not shown) with the Z-axis in the head-to-tail (head-to-foot) direction and the Y-axis in the dorsal ventral (body axis) direction. The X-ray irradiation range irradiated by the X-ray tube 42 is surrounded by the center 42 a of the X-ray tube 42, the left end side 43 a of the X-ray detector 43, and the right end side 43 b of the X-ray detector 43. Range.

  An example of an X-ray image (here, an angio image) generated based on the X-rays detected by the X-ray detector 43 in this irradiation range is shown on the upper side of FIG. The intersection of the perpendicular 2a from the X-ray tube 42 to the X-ray detector 43 and the X-ray detector 43 is defined as an intersection 43c. Further, in the figure shown on the upper side of FIG. 2 (hereinafter referred to as the upper figure), the horizontal direction in the figure is the X-axis direction, and the vertical direction is the Z-axis direction. Further, the upward direction is the head side, and the downward direction is the foot side. Here, the point 2b in the figure is a point obtained by projecting the perpendicular 2a on the X-ray detector 43 onto the angio image. Moreover, 2c in the figure indicates the central axis in the angio image.

  Here, in the lower diagram of FIG. 2, among the X-ray irradiation range irradiated by the X-ray tube 42, the object 2d in the subject P and the irradiation range 2f that passes through the object 2e are shown in the upper diagram of FIG. Is projected onto the region 2g. The object 2d and the object 2e are present at different positions in the body thickness direction of the subject P, but are displayed overlapping each other in the angio image. In other words, there is no information in the body thickness direction of the subject P in the illustrated angio image.

  In addition, as shown in the lower diagram of FIG. 2, X-rays generated from the X-ray tube 42 are irradiated to the X-ray detector 43 so as to spread radially. Therefore, X-rays are irradiated obliquely to the subject P at a position away from the intersection 43 c on the detection surface of the X-ray detector 43. As a result, the object 2d and the object 2e that are at different positions in the body axis direction and the body thickness direction in the subject P are displayed in an overlapping manner on the angio image.

  Conventionally, when a region of interest designated on such an angio image is imaged with an X-ray CT apparatus, the cross-sectional direction of the CT imaging region is included so that each object projected in the region of interest is included. The width is set. Here, in the conventional X-ray CT apparatus, since the CT-X-ray tube and the CT-X-ray detector are usually arranged in a direction orthogonal to the Z-axis direction, the cross-sectional direction of the CT imaging region is the Z-axis direction. Matches. Therefore, for example, when a plurality of objects projected in the region of interest are at different positions in the body axis direction and the body thickness direction, the width in the Z-axis direction in the CT imaging region so as to include each object Is adjusted.

  FIG. 3 is a diagram showing an example of a CT imaging region set by a conventional X-ray CT apparatus. The angio image shown in the upper diagram of FIG. 3 is the same as the angio image shown in the upper diagram of FIG. For example, as shown in FIG. 3, when an area 2g on which the object 2d and the object 2e are projected is designated as a region of interest on the angio image, both the object 2d and the object 2e are included. In addition, the width in the Z-axis direction in the CT imaging region is set. Here, if the distance between the object 2d and the object 2e in the body axis direction is increased, the width in the Z-axis direction in the CT imaging region is also set wider.

  For this reason, in the conventional technique, when a region of interest designated on an X-ray image captured by the X-ray diagnostic apparatus 200 is imaged by the X-ray CT apparatus, a wide CT imaging area may be set. . In addition, in order to set a wide CT imaging region including a plurality of objects, if exact alignment is required when moving the subject to the X-ray CT apparatus side by moving the bed, Work sometimes took time. In addition, when performing such alignment, it may be required to perform pre-scan with an X-ray CT apparatus for confirmation of alignment. As described above, in the conventional technique, a large CT imaging region may be set or a pre-scan may be performed, and as a result, the exposure dose to the subject may increase. In addition, as a result of the time required for alignment, the inspection time may increase.

  Therefore, in the IVR-CT apparatus 10 according to the first embodiment, the system control apparatus 100 captures the region of interest specified on the X-ray image captured by the X-ray diagnostic apparatus 200 by the X-ray CT apparatus 300. In this case, the bed 30 or the CT apparatus gantry 60 is tilted in accordance with the X-ray trajectory irradiated from the X-ray tube 42 and passing through the position corresponding to the region of interest when the X-ray image is taken. Thereby, even when a region of interest including a plurality of objects at different positions in the body axis direction and the body thickness direction is designated, a CT imaging region can be set along the arrangement of each object. When setting the CT imaging region, the width in the cross-sectional direction can be made narrower than in the case where the cross-sectional direction coincides with the Z-axis direction as in a conventional X-ray CT apparatus. As a result, the exposure dose to the subject can be reduced. In addition, the time required for positioning the bed or the like can be shortened.

  FIG. 4 is a diagram illustrating an example of a CT imaging region set by the system control apparatus 100 according to the first embodiment. The lower diagram of FIG. 4 shows a case where the region 2g shown in FIG. 3 is imaged as a region of interest. In the example shown in the lower part of FIG. 4, the bed 30 or the CT apparatus gantry 60 is tilted according to the X-ray trajectory transmitted through the position corresponding to the region of interest when the X-ray image is taken by the X-ray diagnostic apparatus 200. It has been. Therefore, as shown in the lower diagram of FIG. 4, the width in the cross-sectional direction of the CT imaging region 4 a can be reduced until the width is approximately the same as the width of the object 2 d and the object 2 e. 4 shows an example of a tomographic image obtained by imaging the CT imaging region 4a shown in the lower diagram of FIG. As shown in the upper diagram of FIG. 4, when the CT imaging region 4a shown in the lower diagram of FIG. 4 is imaged, the object 2d and the object 2e in the subject P are maintained in the body thickness direction information. Displayed in the same tomographic image.

  In the IVR-CT apparatus 10 according to the first embodiment, the calculation unit 110 and the movement control unit 106 of the system control apparatus 100 execute the above-described processing. Below, the process performed by the calculation part 110 and the movement control part 106 is demonstrated in detail.

  First, processing executed by the calculation unit 110 will be described with reference to FIG. FIG. 5 is a diagram for explaining processing executed by the calculation unit 110 according to the first embodiment. The lower diagram of FIG. 5 shows an example in which X-rays irradiated from the X-ray tube 42 pass through the subject P and are detected by the X-ray detector 43. The upper diagram in FIG. 5 shows an example of an X-ray image (here, an angio image) generated based on the X-rays detected by the X-ray detector 43. FIG. 5 illustrates a case where the region of interest 5a is set on the angio image by the setting unit 105. Moreover, 43d in the lower figure of FIG. 5 has shown the position of the region of interest 5a set to the angio image.

  The calculation unit 110 passes through a line segment connecting the X-ray tube 42 and the X-ray detector 43 at the shortest distance, and a position corresponding to the region of interest irradiated from the X-ray tube 42 when an X-ray image is captured. The angle between the X-ray trajectory and the inclination angle is calculated. Here, the length of the line segment connecting the X-ray tube 42 and the X-ray detector 43 with the shortest distance matches the SID.

For example, the calculation unit 110 calculates a distance d from the center axis 5b of the angio image to the center of the region of interest 5a as shown in the upper diagram of FIG. Here, the calculation unit 110 converts the distance d into a length (length: mm) according to the pixel size of the X-ray detector 43. Moreover, the calculation part 110 acquires the value of SID shown in the lower figure of FIG. The calculation unit 110 acquires the SID value from the movement control unit 106, for example. Then, the calculation unit 110 calculates the tilt angle based on the calculated distance d and the acquired SID value. Specifically, the calculation unit 110 calculates the tilt angle based on Tan ⁻¹ (d / SID).

  Next, processing executed by the movement control unit 106 will be described with reference to FIGS. 6 and 7. 6 and 7 are diagrams for explaining processing executed by the movement control unit 106 according to the first embodiment. FIG. 6 shows the position of the top 31 at the time of imaging by the X-ray diagnostic apparatus 200.

  Based on the angle calculated by the calculation unit 110, the movement control unit 106 generates a CT-ray on the X-ray trajectory irradiated from the X-ray tube 42 and passing through a position corresponding to the region of interest when an X-ray image is captured. The top plate 31 or the CT apparatus gantry 60 is tilted so that the X-ray scanning surfaces irradiated from the X-ray tube 62 overlap.

  Specifically, the movement control unit 106 first moves at least one of the top plate 31 or the CT apparatus gantry 60 so that the axis formed by the CT-X-ray tube 62 and the CT-X-ray detector 63 is an angio image. Align with the central axis. This position is set as an initial setting position: 7a.

  The movement control unit 106 tilts the CT gantry 60 and scans the X-ray irradiated from the CT-X-ray tube 62 on the X-ray trajectory irradiated from the X-ray tube 42 and passed through the position corresponding to the region of interest. In order to overlap, the top plate 31 is set at the position of the CT isocenter 6b as shown in the right figure of FIG. For this purpose, the movement control unit 106 needs to move the top 31 by the adjustment distance A and move the CT apparatus gantry 60 by the correction distance C from the initial setting position 7a.

  In the right diagram of FIG. 7, the positions of the top plate 31, the X-ray tube 42, and the X-ray detector 43 moved by the adjustment distance A are respectively the top plate 31 ′, the X-ray tube 42 ′, and the X-ray detection. It is shown as vessel 43 '. The height H indicates the distance between the X-ray tube 42 'and the CT isocenter 6b. The movement control unit 106 calculates the correction distance C using the height H and the inclination angle calculated from the X-ray diagnostic apparatus 200. Specifically, the movement control unit 106 calculates the correction distance C using Tan (inclination angle) × height H.

  In this way, the top plate 31 is moved by the adjustment distance A, and the gantry 60 is moved by the correction distance C and tilted by the inclination angle, so that the X-ray tube 42 irradiates and passes the position corresponding to the region of interest. Scanning of X-rays emitted from the CT-X-ray tube 62 can be superimposed on the X-ray trajectory.

  Next, processing executed by the correction unit 111 will be described with reference to FIGS. 8A and 8B. 8A and 8B are diagrams for explaining processing executed by the correction unit 111 according to the first embodiment.

  FIG. 8A shows a case where the angle of the CT apparatus gantry 60 is not inclined with respect to the subject P. 8a in FIG. 8A shows a tomographic image generated when the angle of the CT apparatus gantry 60 is not tilted. In the subject P shown in FIG. 8A, when the distance in the height direction from the observation object 8b is A, the distance in the height direction from the observation object 8b is also A in the tomographic image 8a.

  FIG. 8B shows a case where the CT apparatus gantry 60 is tilted with respect to the subject P by an angle corresponding to the tilt angle. 8c in FIG. 8B indicates a tomographic image generated when the CT apparatus gantry 60 is tilted at an angle corresponding to the tilt angle. In the subject P in FIG. 8B, when the distance in the height direction from the observation object 8b is A, the distance in the height direction from the observation object 8b in the tomographic image 8c is A ′ (= A / COSθ, where the inclination angle is θ).

  Thus, the distance in the height direction of the tomographic image generated by the tomographic image data generation unit 108 changes according to the inclination angle. On the other hand, when the CT apparatus gantry 60 is tilted with respect to the subject P by an angle corresponding to the tilt angle, the distance in the height direction is displayed as A ′ on the monitor 20. However, when performing a procedure such as puncture based on a tomographic image, the puncture needle is often inserted straight into the subject. For this reason, the distance to the actual puncture target is A, which is shorter than the distance A ′ in the height direction displayed on the monitor 20. Therefore, when the tomographic image 8c is displayed on the monitor 20, the correction unit 111 also displays A corrected in addition to A ′ as the distance in the height direction from the observation target 8b.

  Next, a processing procedure performed by the system control apparatus 100 will be described with reference to FIG. FIG. 9 is a flowchart illustrating a processing procedure performed by the system control apparatus 100 according to the first embodiment. As shown in FIG. 9, the calculation unit 110 determines whether or not the setting of the region of interest has been accepted (step S101). Here, if the calculation unit 110 determines that the setting of the region of interest has been accepted (step S101, Yes), the line segment connecting the X-ray tube 42 and the X-ray detector 43 with the shortest distance, and the X-ray tube An inclination angle that is an angle formed by the locus of X-rays irradiated from 42 is calculated (step S102).

  In addition, the movement control unit 106 moves the CT apparatus gantry 60 to set the bed 30 and the CT apparatus gantry 60 to the initial setting positions (step S103). Note that the movement control unit 106 may set the bed 30 and the CT apparatus gantry 60 to the initial setting position by moving the bed 30. Further, the movement control unit 106 moves the bed 30 so as to coincide with the height position of the CT isocenter 6b (step S104).

  The movement control unit 106 calculates a correction distance that is a movement distance from the initial setting position to the correction position (step S105). Then, the movement control unit 106 sets the CT apparatus gantry 60 to the correction position by moving the CT apparatus gantry 60 by a correction distance from the initial setting position (step S106). Note that the movement control unit 106 may set the CT apparatus gantry 60 to the correction position by moving the bed 30 from the initial setting position by a correction distance. Then, the movement control unit 106 tilts the CT apparatus gantry 60 at an inclination angle (step S107).

  In addition, the calculation part 110 repeats the determination process of step S101, when it determines with having received the setting of the region of interest (step S101, No). Further, the processing procedure by the system control apparatus 100 is not limited to the order shown in FIG. 9, and the processing order may be changed. For example, the movement control unit 106 may execute the processes after Step S103 and Step S105 after executing the process of calculating the correction distance in Step S104.

  As described above, the IVR-CT apparatus 10 according to the first embodiment emits X-rays that have been irradiated from the X-ray tube 42 and passed through a position corresponding to the region of interest of the subject P when taking an X-ray image. The CT apparatus gantry 60 is tilted so that the locus and the X-ray scanning surface irradiated from the CT-X-ray tube 62 overlap. Thereby, in the IVR-CT apparatus 10, the CT imaging region can be set narrower than in the case where the CT imaging region is set by widening the width orthogonal to the Z-axis direction of the subject P. Therefore, the IVR-CT apparatus 10 according to the first embodiment can reduce the X-ray dose irradiated to the subject P. Thereby, according to the IVR-CT apparatus 10, the exposure dose of the subject P can be reduced.

  In the IVR-CT apparatus 10, the setting of the position of the CT apparatus gantry 60 in the Z-axis direction of the subject P is automated. For this reason, the pre-scan process for aligning positions can be omitted. Thereby, according to 1st Embodiment, the exposure of the subject P by a prescan process can be reduced. Further, in the IVR-CT apparatus 10, imaging can be easily switched between the X-ray diagnostic apparatus 200 and the X-ray CT apparatus 300. Thereby, according to the IVR-CT apparatus 10, the inspection time can be shortened.

(Second Embodiment)
In the first embodiment, the case where the movement control unit 106 tilts the CT apparatus gantry 60 has been described. On the other hand, in the IVR-CT apparatus 10, the bed 30 may be inclined at an inclination angle without inclining the CT apparatus gantry 60. Therefore, in the second embodiment, a case where the bed 30 is inclined at an inclination angle will be described.

  The case where the movement control unit 106 according to the second embodiment tilts the bed 30 at an inclination angle will be described with reference to FIG. FIG. 10 is a diagram illustrating an example when the movement control unit 106 according to the second embodiment tilts the bed 30 at an inclination angle. The left diagram in FIG. 10 is a diagram showing the position of the top plate 31 at the time of imaging by the X-ray diagnostic apparatus 200, and the right diagram in FIG. FIG. 6 is a diagram showing the position of the device gantry 60. In addition, the left figure of FIG. 10 is the same as the left figure of FIG.

  Similar to FIG. 6, the movement control unit 106 sets the CT apparatus gantry 60 and the bed 30 to the initial setting position 7a, and then moves the bed 30 by an adjustment distance A in the height direction, thereby isolating the isocenter of the X-ray diagnostic apparatus. And CT isocenter are matched. Then, as shown in the right diagram of FIG. 10, during imaging by the X-ray CT apparatus 300, the movement control unit 106 is placed on the bed 30 on the foot side in the movement amount Z-axis direction corresponding to the correction distance C from the initial setting position 7 a. Is moved to set the CT apparatus gantry 60 at the correction position 7d. The movement control unit 106 sets the CT apparatus gantry 60 to the correction position 7d by moving the CT apparatus gantry 60 from the initial setting position 7a to the head side in the movement amount Z-axis direction corresponding to the correction distance C. Also good.

  Then, the movement control unit 106 sets the bed 30 based on the angle calculated by the calculation unit 110 so that the X-ray trajectory of the X-ray CT apparatus 300 overlaps the X-ray trajectory of the X-ray diagnostic apparatus 200. Tilt an angle corresponding to the tilt angle. In the right diagram of FIG. 10, the positions of the X-ray tube 42 and the X-ray detector 43 that have been moved by the adjustment distance A are indicated as the X-ray tube 42 ′ and the X-ray detector 43 ′, respectively. ing. Further, in the right diagram of FIG. 10, the position when the top plate 31 is moved by the adjustment distance A and further tilted by an angle corresponding to the tilt angle is shown as a top plate 31 ″.

  As described above, the IVR-CT apparatus 10 according to the second embodiment uses the X-ray trajectory that is irradiated from the X-ray tube 42 and passes through the position corresponding to the region of interest of the subject P when the X-ray image is captured. The bed 30 is tilted so that the X-ray scanning surface irradiated from the CT-X-ray tube 62 overlaps. Therefore, the IVR-CT apparatus 10 according to the second embodiment can reduce the X-ray dose irradiated to the subject P. Thereby, according to the IVR-CT apparatus 10, the exposure dose of the subject P can be reduced.

(Modification)
In the first embodiment, the case where the movement control unit 106 tilts the CT apparatus gantry 60 has been described. However, when the angle of the rotary frame 61 can be tilted in the CT apparatus gantry 60, the movement control unit 106 moves the CT apparatus gantry 60. The rotation frame 61 may be inclined at an inclination angle without being inclined.

  For example, when the set CT imaging region is wide and volume data can be generated, the correction unit 111 uses the tomographic image data generated based on the X-rays detected by the CT-X-ray detector 63. You may reconstruct tomographic image data without the inclination of an angle. The operation of reconstructing tomographic image data without an angle inclination by the correction unit 111 will be described with reference to FIG. FIG. 11 is a diagram illustrating an example of an operation of reconstructing tomographic image data having no angle inclination by the correction unit 111 according to the first embodiment.

  Reference numeral 10a shown in the lower left side of FIG. 11 shows one tomographic image including the observation object 10b among a plurality of tomographic images generated when the angle of the CT apparatus gantry 60 is tilted. In the subject P shown in the upper diagram of FIG. 11, when the distance in the height direction from the observation object 10b is A, the distance in the height direction from the observation object 10b in the tomographic image 10a is A ′ (= A / COSθ, where And the inclination angle is θ). Here, the correction unit 111 reconstructs the tomographic image 10c having no angle inclination using the volume data. In the tomographic image 10c reconstructed by the correction unit 111 in this way, the distance in the height direction from the observation target 10b is A.

  According to the IVR-CT apparatus of at least one embodiment described above, the exposure dose can be reduced.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 IVR-CT apparatus 30 Bed 41 C-arm 61 Rotating frame 100 System control part 105 Setting part 106 Movement control part 110 Calculation part

Claims (4)

A bed on which the subject is placed;
A first support unit that supports a first X-ray tube and a first X-ray detector that detects X-rays irradiated from the first X-ray tube and transmitted through the subject;
A second X-ray tube and a second X-ray detector that detects X-rays emitted from the second X-ray tube are opposed to each other across an imaging space in which the bed is moved. A second support unit that supports and moves the second X-ray tube and the second X-ray detector on a circular orbit surrounding the imaging space;
A setting unit that sets a region of interest on an X-ray image generated based on the X-rays detected by the first X-ray detector;
X-rays that have passed through a plurality of objects that are irradiated from the first X-ray tube and projected onto the region of interest at the time of taking the X-ray image and that are at different positions in the body axis direction and the body thickness direction . A calculation unit that calculates an angle between a trajectory and a scanning plane of X-rays emitted from the second X-ray tube , which is orthogonal to the body axis direction ;
Based on the angle calculated by the calculation unit, the bed or the second support unit is arranged so that the X-ray trajectory of the X-ray irradiated from the second X-ray tube overlaps the X-ray trajectory. An IVR-CT apparatus comprising: a tilting control unit.   The control unit includes: a first isocenter located between the first X-ray tube and the first X-ray detector; a second X-ray tube and the second X-ray detector; The distance between the second isocenter located in the middle, the distance between the position of the first X-ray tube and the second isocenter at the time of taking the X-ray image, and the calculation unit Based on the calculated angle, the amount of movement of the bed or the second support portion in the horizontal direction is calculated, the bed or the second support portion is moved in the horizontal direction by the calculated amount of movement, and The IVR-CT apparatus according to claim 1, wherein the bed or the second support portion is inclined by an angle calculated by the calculation unit.   And a correction unit that corrects a distance on the tomographic image generated based on the X-ray detected by the second X-ray detector according to the angle calculated by the calculation unit. The IVR-CT apparatus according to claim 1 or 2.   The image processing apparatus further includes a correction unit that reconstructs tomographic image data having no angle inclination using volume data generated based on the X-rays detected by the second X-ray detector. The IVR-CT apparatus according to claim 1 or 2.

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