JP2020099593A - Angio ct apparatus - Google Patents

Abstract

To reduce the difference of the inclination of the top plate when moving the top plate to perform angio imaging and CT imaging in an alternating manner.SOLUTION: An angio CT apparatus according to the embodiment includes an acquisition unit and a top plate control unit. On the basis of a CT image obtained by imaging a subject with a CT gantry that has an opening into which the top plate is pulled out and moved from a support frame that movably supports the top plate on which the subject is placed, the acquisition unit acquires information about the warping of the top plate at the imaging position of the CT image. When the top plate is moved from the imaging position of the CT image and the subject is arranged at the imaging position of an angio image to be taken by an angio gantry arranged in the vicinity of the support frame, the top plate control unit tilts, on the basis of the information, the top plate to reproduce the inclination of the top plate due to the warping.SELECTED DRAWING: Figure 1

Description

Embodiments of the present invention relate to an angio CT (Computed Tomography) apparatus.

There is an angio CT device in which an angio gantry and a CT gantry are installed in one room. This type of angio CT apparatus can switch between angio imaging and CT imaging, and one of two arrangement methods is used. The first arrangement method is used, for example, when scanning the whole body of a subject in a traffic accident. One of the angio gantry and the CT gantry is placed on the top plate on which the subject is placed, and the other It is a method of evacuating. The second arrangement method is used, for example, when scanning a part of the subject, and is a method of moving the top plate on which the subject is placed with respect to the angio gantry and the CT gantry at fixed positions. Such a second arrangement method has an advantage that shooting can be switched more quickly than the first arrangement method. Therefore, the following description is based on the second arrangement method.

In the second arrangement method, the angio CT apparatus moves the top plate along the longitudinal direction to switch between angio imaging and CT imaging so that the imaging can be performed. In this case, the angio CT device is used, for example, in liver intervention to determine whether or not to perform embolization therapy on cancer cells in the liver. Angio imaging is used when operating a catheter to insert it into an artery, and CT imaging is used when diagnosing whether embolization therapy is to be performed. For example, a doctor may perform embolization therapy when cancer cells are hardly imaged by imaging from the portal vein and cancer cells are clearly imaged by imaging from arteries in two times of enhanced CT. To be judged. Thereby, embolization (Embolization) is performed on the feeding blood vessels to the cancer cells under the fluoroscopic imaging by the angiogantry. Embolization of the feeding vessels does not stop the blood flow from the portal vein, so normal cells are hardly damaged. In addition, the blood flow from the artery is blocked by the embolization of the feeding blood vessels, and the cancer cells are damaged. This is the outline of transcatheter arterial embolization (TAE).

The angio CT device as described above is not particularly problematic, but according to the study by the present inventor, when the angio imaging and the CT imaging are performed alternately by moving the table, the tilt of the table is not detected. There is room for improvement in that we want to reduce the difference. That is, when the top plate is moved to perform angiography and CT imaging, the inclination of the top plate is different because the top plate bends differently between the angio image capturing position and the CT image capturing position. Occurs. Along with this, a deviation occurs between the obtained angio image and the CT image. Therefore, from the viewpoint of reducing such a shift between images, it is preferable to reduce the difference in the inclination of the tabletop between the imaging position of the angio image and the imaging position of the CT image.

JP-A-2014-330

The problem to be solved by the present invention is to reduce the difference in the inclination of the top plate when the top plate is moved and the angio imaging and the CT imaging are performed alternately.

The angio CT device according to the embodiment includes an acquisition unit and a top control unit.
The acquisition unit is obtained by photographing the subject with a CT gantry having an opening into which the moved top plate is pulled out from a support frame that movably supports the top plate on which the subject is placed. Based on the CT image, information regarding the deflection of the top plate at the imaging position of the CT image is acquired.
The tabletop control unit moves the tabletop from the imaging position of the CT image to place the object at the imaging position of the angio image by the angiogantry arranged near the support frame, and the information Based on the above, the top plate is tilted so as to reproduce the inclination due to the deflection of the top plate.

FIG. 1 is a block diagram showing the configuration of the angio CT apparatus according to the first embodiment. FIG. 2 is a perspective view showing the external appearance of the angio CT apparatus according to the first embodiment. FIG. 3 is a schematic diagram for explaining an example of the CT image according to the first embodiment. FIG. 4 is a schematic diagram for explaining an example of the patient load table according to the first embodiment. FIG. 5 is a flow chart for explaining the operation in the first embodiment. FIG. 6 is a schematic diagram for explaining the operation of step ST2 in the first embodiment. FIG. 7 is a schematic diagram for explaining the operation of steps ST5 and ST6 in the first embodiment. FIG. 8 is a flow chart for explaining the operation in the first embodiment. FIG. 9 is a schematic diagram for explaining the operation of step ST12 in the first embodiment. FIG. 10 is a schematic diagram for explaining the operation of step ST14 in the first embodiment. FIG. 11 is a schematic diagram for explaining the operation of step ST16 in the first embodiment. FIG. 12 is a schematic diagram for explaining the tilt sensor according to the first modified example of the first embodiment. FIG. 13 is a schematic diagram for explaining the correction table according to the first modified example of the first embodiment. FIG. 14 is a schematic diagram for explaining the operation of the second modification of the first embodiment. FIG. 15 is a plan view for explaining the angio CT device according to the second embodiment. FIG. 16 is a flow chart for explaining the operation in the second embodiment. FIG. 17 is a schematic diagram for explaining the interference region according to the second embodiment. FIG. 18 is a schematic diagram for explaining an initially set interference region according to the second embodiment. FIG. 19 is a flowchart for explaining the operation in the third embodiment. FIG. 20 is a schematic diagram for explaining the operation of step ST7b-1 in the third embodiment. FIG. 21 is a flow chart for explaining the operation in the fourth embodiment. FIG. 22 is a schematic diagram for explaining the operation of step ST4c-2 in the fourth embodiment.

Hereinafter, the angio CT apparatus according to each embodiment will be described with reference to the drawings.

<First Embodiment>
FIG. 1 is a block diagram showing the configuration of the angio CT apparatus according to the first embodiment, and FIG. 2 is a perspective view showing the appearance of the angio CT apparatus. The angio CT device 1 includes an angio gantry 10, a CT gantry 30, a bed device 50, and a console device 70. The angio gantry 10 includes a high voltage generator 11, an X-ray generator 12, an X-ray detector 13, a C arm 14, a state detector 141, and a C arm drive device 142.

The high voltage generator 11 generates a high voltage applied between the anode and the cathode in order to accelerate thermoelectrons generated from the cathode of the X-ray tube and outputs the high voltage to the X-ray tube.

The X-ray generation unit 12 includes an X-ray tube that irradiates the subject P with X-rays, an ROI (Region Of Interest) filter having a function of attenuating or reducing the irradiation X-ray dose, and an X-ray diaphragm.

The X-ray tube produces X-rays. Specifically, the X-ray tube is a vacuum tube that holds a cathode that generates thermoelectrons and an anode that receives thermoelectrons flying from the cathode and generates X-rays. For example, an X-ray tube includes a rotary anode type X-ray tube that generates X-rays by irradiating a rotating anode with thermoelectrons. The X-ray tube is connected to the high voltage generator 11 via a high voltage cable. A high voltage generator 11 applies a tube voltage between the cathode and the anode. The application of the tube voltage causes thermoelectrons to fly from the cathode to the anode. A tube current flows by thermionic electrons flying from the cathode to the anode. By applying a high voltage and supplying a filament current from the high voltage generator 11, thermoelectrons fly from the cathode toward the anode, and the thermoelectrons collide with the anode to generate X-rays.

The ROI filter is located between the X-ray tube and the X-ray diaphragm and is made of a metal plate such as copper or aluminum. The ROI filter has an opening region in at least a part, for example, a central portion, and attenuates X-rays outside the opening region. Therefore, the ROI filter completely transmits the X-rays in the X-ray passing region in the opening region and attenuates and transmits the X-rays in the other regions. The ROI filter is driven by a driving device (not shown) according to the region of interest input by the operator from the input interface 73.

The X-ray diaphragm is located between the X-ray tube and the X-ray detector 13, and is composed of a lead plate as a metal plate. The X-ray diaphragm blocks the X-rays outside the opening area so that the X-rays generated by the X-ray tube are narrowed down so that only the region of interest of the subject P is irradiated. For example, the X-ray diaphragm has four diaphragm blades, and by sliding these diaphragm blades, the X-ray shielded area is adjusted to an arbitrary size. The diaphragm blades of the X-ray diaphragm are driven by a driving device (not shown) according to the region of interest input by the operator from the input interface 73.

The X-ray detector 13 detects X-rays transmitted through the subject P. As such an X-ray detector 13, it is possible to use one that directly converts X-rays into electric charges, and one that converts X-rays into light and then into electric charges. Here, the former will be described as an example, but the latter. It doesn't matter. That is, the X-ray detector 13 is, for example, a planar FPD (Flat Panel Detector) that converts the X-rays that have passed through the subject P into charges and accumulates the charges, and a drive for reading the charges accumulated in the FPD. And a gate driver that generates a pulse. The size of the FPD is typically 8-12 inches. The FPD is configured by arranging minute detection elements two-dimensionally in the column direction and the line direction. Each detection element senses an X-ray and generates a charge according to the incident X-ray dose, a charge storage capacitor that stores the charge generated in this photoelectric film, and a predetermined amount of charge stored in the charge storage capacitor. The TFT (thin film transistor) which outputs at the timing of is provided. The accumulated charges are sequentially read by the drive pulse supplied by the gate driver.

A projection data generation circuit and a projection data storage circuit (not shown) are provided at the subsequent stage of the X-ray detector 13. The projection data generation circuit includes a charge/voltage converter that converts charges read in parallel from the FPD in units of rows or columns into a voltage, and an A/D converter that converts the output of the charge/voltage converter into a digital signal. It is provided with a converter and a parallel/serial converter for converting a digitally converted parallel signal into a time-series serial signal. The projection data generation circuit supplies this serial signal to the projection data storage circuit as time-series projection data. The projection data storage circuit sequentially stores the time-series projection data supplied from the projection data generation circuit to generate two-dimensional projection data. This two-dimensional projection data is stored in the memory 71.

The C-arm 14 holds the X-ray generation unit 12 and the X-ray detector 13 so as to face each other with the subject P and the top plate 53 interposed therebetween, so that the X-ray imaging of the subject P on the top plate 53 is performed. It has a configuration that can be performed.

Specifically, as shown in FIG. 2, the C-arm 14 is movable under a plurality of rails r2 provided on the ceiling along the major axis direction or the minor axis direction of the top plate 53, and is also illustrated. The non-moving mechanism makes it possible to move between the rails r2 along the major axis direction and the minor axis direction of the top plate 53. Further, the C arm 14 is supported by the support arm 14b via the holding portion 14a. The support arm 14b has a substantially arc shape, and has a base end attached to a moving mechanism for the rail r2. The C-arm 14 is rotatably held by the holding portion 14a about an axis in the X direction orthogonal to both the Y direction perpendicular to the top plate 53 and the Z direction along the long axis direction of the top plate 53. There is. Further, the C-arm 14 has a substantially arc shape centered on the Z-direction axis, and is held by the holding portion 14a so as to be slidable along the substantially arc shape. That is, the C arm 14 can perform a sliding operation with the Y-direction axis as the center of rotation. Further, the C-arm 14 can perform a rotation operation (hereinafter, referred to as “main rotation operation”) about an axis in the X direction about the holding portion 14a, and various operations can be performed depending on a combination of slide and this rotation. It is possible to observe an X-ray image from the angle direction. Further, the C-arm 14 can also rotate about the axis in the Z direction, and thus, for example, the rotation center axis of the above-described sliding operation can be set in the X direction. An imaging axis that passes through the X-ray focal point of the X-ray generation unit 12 and the center of the detection surface of the X-ray detector 13 intersects the rotation center axis of the slide operation and the rotation center axis of the main rotation operation at one point. Is designed to be. The intersection is generally called an isocenter. The isocenter does not displace even when the C arm 14 performs the above-described sliding operation or main rotating operation. Therefore, when the region of interest is located at the isocenter, it becomes easy to observe the region of interest in the moving image of the medical image obtained by the sliding operation or the main rotating operation of the C arm 14.

Returning to FIG. 1, the C-arm 14 is an appropriate portion to which a plurality of power sources for realizing the operations related to the support arm 14b under the rail r2, the X-direction axis, the Y-direction axis, and the Z-direction axis correspond. Is equipped with. These power sources constitute the C-arm drive device 142. The C-arm drive device 142 reads the drive signal from the drive control function 742 and causes the C-arm 14 to slide, rotate, and linearly move. Further, the C-arm 14 is provided with a state detector 141 for detecting information on its angle, posture, or position. The state detector 141 includes, for example, a potentiometer that detects a rotation angle and a movement amount, an encoder that is a position detection sensor, and the like. As the encoder, a so-called absolute encoder of magnetic type, brush type, photoelectric type, or the like can be used. Further, as the state detector 141, various types of position detection mechanisms such as a rotary encoder that outputs a rotational displacement as a digital signal or a linear encoder that outputs a linear displacement as a digital signal can be appropriately used.

The CT gantry 30 includes an X-ray tube 31, an X-ray detector 32, a rotating frame 33, an X-ray high voltage device 34, a CT controller 35, a wedge 36, a collimator 37, and a DAS 38. Although a plurality of CT gantry 30 is shown in FIG. 1 from the viewpoint of showing the relationship with the bed apparatus 50, the CT gantry 30 of the present embodiment is one.

The X-ray tube 31 generates X-rays. Specifically, the X-ray tube 31 is a vacuum tube that holds a cathode that generates thermoelectrons and an anode that receives thermoelectrons flying from the cathode and generates X-rays. For example, the X-ray tube 31 includes a rotating anode type X-ray tube that generates X-rays by irradiating a rotating anode with thermoelectrons. The X-ray tube 31 is connected to the X-ray high voltage device 34 via a high voltage cable. A tube voltage is applied by the X-ray high voltage device 34 between the cathode and the anode. The application of the tube voltage causes thermoelectrons to fly from the cathode to the anode. A tube current flows by thermionic electrons flying from the cathode to the anode. By applying a high voltage and supplying a filament current from the X-ray high voltage device 34, thermoelectrons fly from the cathode toward the anode, and the thermoelectrons collide with the anode, whereby X-rays are generated.

The X-ray detector 32 detects the X-rays emitted from the X-ray tube 31 and passed through the subject P, and outputs an electric signal corresponding to the X-ray dose to the DAS 38. The X-ray detector 32 has, for example, a plurality of X-ray detection element arrays in which a plurality of X-ray detection elements are arranged in the channel direction along one arc centering on the focal point of the X-ray tube. The X-ray detector 32 has, for example, a structure in which a plurality of X-ray detection element rows in which a plurality of X-ray detection elements are arranged in the channel direction are arranged in the slice direction (row direction, row direction). The X-ray detector 32 is, for example, an indirect conversion type detector including a grid, a scintillator array, and an optical sensor array.

The scintillator array has a plurality of scintillators, and the scintillator has a scintillator crystal that outputs light of a photon amount according to the incident X-ray dose.

The grid is arranged on the X-ray incident side surface of the scintillator array, and has an X-ray shielding plate having a function of absorbing scattered X-rays. The grid may be called a collimator (one-dimensional collimator or two-dimensional collimator).

The photosensor array has a function of converting into an electric signal according to the amount of light from the scintillator, and has, for example, a photosensor such as a photomultiplier tube (photomultiplier: PMT).

The X-ray detector 32 may be a direct conversion type detector having a semiconductor element that converts an incident X-ray into an electric signal. The X-ray detector 32 is an example of an X-ray detector.

The rotating frame 33 is an annular frame that supports the X-ray tube 31 and the X-ray detector 32 rotatably around the rotation axis Z. Specifically, the rotating frame 33 is housed in the CT gantry 30 and supports the X-ray tube 31 and the X-ray detector 32 which are arranged to face each other through the opening 30a. The rotating frame 33 is supported by a fixed frame (not shown) so as to be rotatable about the rotation axis Z. The CT frame 35 is rotated about the rotation axis Z by the CT control device 35 to rotate the X-ray tube 31 and the X-ray detector 32 about the rotation axis Z. The rotary frame 33 receives power from the drive mechanism of the CT controller 35 and rotates about the rotation axis Z at a constant angular velocity. An image field of view (FOV) is set in the opening of the rotating frame 33.

In the present embodiment, the longitudinal direction of the rotary shaft of the rotary frame 33 or the top plate 53 of the bed apparatus 50 in the non-tilted state is the Z-axis direction, the axis direction orthogonal to the Z-axis direction and horizontal to the floor surface. Is defined as the Y-axis direction, which is orthogonal to the X-axis direction and the Z-axis direction and perpendicular to the floor surface.

The X-ray high-voltage device 34 has an electric circuit such as a transformer and a rectifier, and a high-voltage generator that generates a high voltage applied to the X-ray tube 31 and a filament current supplied to the X-ray tube 31. , And an X-ray control device that controls the output voltage according to the X-rays emitted by the X-ray tube 31. The high voltage generator may be a transformer type or an inverter type. The X-ray high voltage device 34 may be provided in the rotating frame 33 in the CT gantry 30 or in a fixed frame (not shown) in the CT gantry 30.

The CT control device 35 controls the X-ray high voltage device 34 and the DAS 38 in order to execute X-ray CT imaging according to the imaging control function 733 of the processing circuit 74 of the console device 70. The CT control device 35 has a processing circuit having a CPU and the like, and a drive mechanism such as a motor and an actuator. The processing circuit has, as hardware resources, a processor such as a CPU or MPU and a memory such as ROM or RAM. Further, the CT control device 35 may be realized by an ASIC, FPGA, CPLD, SPLD.

The CT control device 35 has a function of receiving an input signal from an input interface 73, which will be described later, attached to the console device 70 or the CT gantry 30 and controlling the operation of the CT gantry 30 and the bed device 50. For example, the CT control device 35 receives the input signal and controls the rotating frame 33 to rotate, the CT gantry 30 to tilt, and the bed device 50 and the top plate 53 to operate. The control for tilting the CT gantry 30 is performed by rotating the CT control device 35 about an axis parallel to the X-axis direction based on the tilt angle (tilt angle) information input by the input interface 73 attached to the CT gantry 30. It is realized by rotating the frame 33. The CT control device 35 may be provided in the CT gantry 30 or the console device 70.

The wedge 36 adjusts the dose of X-rays with which the subject P is irradiated. Specifically, the wedge 36 attenuates the X-ray so that the dose of the X-ray irradiated from the X-ray tube 31 to the subject P has a predetermined distribution. For example, as the wedge 36, a metal plate such as a wedge filter (wedge filter) or a bow-tie filter (aluminum) is used.

The collimator 37 limits the irradiation range of the X-ray transmitted through the wedge 36. The collimator 37 slidably supports a plurality of lead plates that shield X-rays and adjusts the form of slits formed by the plurality of lead plates.

The DAS 38 (Data Acquisition System) receives the information on the incident channel output from the X-ray detector 32 for each view period to collect detection data having a digital value corresponding to the X-ray dose over the view period. To do. The DAS 38 is realized by, for example, an ASIC equipped with a circuit element capable of generating detection data. The detection data is transmitted to the console device 70 via a non-contact data transmission device or the like.

The CT gantry 30 is a Rotate/Rotate-Type (third generation CT) in which an X-ray generator and an X-ray detector integrally rotate around the subject, and a large number of X-ray detectors arrayed in a ring shape. There are various types such as Stationary/Rotate-Type (fourth generation CT) in which the element is fixed and only the X-ray generation unit rotates around the subject, and any type is applicable to one embodiment.

The couch device 50 is a device for placing and moving the subject P, and includes a base 51, a couch driving device 52, a top plate 53, and a support frame 54.

The base 51 is a housing that is installed on the floor and supports the support frame 54 so as to be movable in the vertical direction (Y direction).

The couch driving device 52 is housed in the housing of the couch device 50 and includes a motor or an actuator that moves the top plate 53 on which the subject P is placed in the longitudinal direction (Z direction) of the top plate 53. The bed driving device 52 reads the drive signal from the drive control function 742 and moves the top plate 53 in the horizontal direction or the vertical direction with respect to the floor surface. Similarly, the bed driving device 52 reads the drive signal from the drive control function 742 and tilts the table 53 around the short axis direction of the table 53. The bed driving device 52 may tilt the top plate 53 by tilting the support frame 54. When the C arm 14 or the top plate 53 moves, the positional relationship of the imaging axis with respect to the subject P changes. The bed driving device 52 may move the support frame 54 in the longitudinal direction of the top plate 53 in addition to the top plate 53.

The top plate 53 is a plate which is provided on the upper surface of the support frame 54 and on which the subject P is placed.

The support frame 54 movably supports the top plate 53 on which the subject P is placed. Specifically, the support frame 54 is provided on the upper portion of the base 51 and supports the top plate 53 slidably along the longitudinal direction thereof.

The console device 70 includes a memory 71, a display 72, an input interface 73, and a processing circuit 74.

The memory 71 includes a memory body such as an HDD (Hard Disk Drive) for recording electrical information, and peripheral circuits such as a memory controller and a memory interface attached to the memory body. The memory 71 is, for example, a program executed by the processing circuit 74, detection data received from the DAS 38, a medical image generated by the processing circuit 74, data used for the processing of the processing circuit 74, various tables, and data in the middle of processing. And the processed data and the like are stored. Examples of medical images include CT images, 3D-CT images, 3D angio images, 2D angio images, superposed images, and processed images. Note that the CT image g1 shown in FIG. 3 is an image of the subject placed on the top plate 53 in the direction Lt that is inclined by the angle θ from the horizontal direction Lh with respect to the floor surface. The angle θ is information regarding the deflection of the top plate 53 pulled out from the support frame 54, and tends to increase according to the amount of movement (the amount of pulling out) of the top plate 53 and the weight of the subject P. This angle θ may be appropriately called by a desired name such as “tilt angle regarding deflection” or “angle of top plate sag”. As various tables, there is a patient load table 71a as shown in FIG. In the patient load table 71a, the angle at which the top plate 53 is tilted is described in association with the movement amount (withdrawal amount) of the top plate 53 and the weight of the subject P described above. The patient load table 71a may include the height of the subject P in addition to the weight of the subject P.

The display 72 includes a display main body that displays various information such as medical images, an internal circuit that supplies a display signal to the display main body, and peripheral circuits such as a connector and a cable that connect the display main body and the internal circuit. There is. The internal circuit superimposes supplementary information such as subject information and projection data generation conditions on the image data supplied from the image processing function 744 of the processing circuit 74 to generate display data, and D/D is added to the obtained display data. A conversion and TV format conversion are performed and displayed on the display body. For example, the display 72 outputs a medical image generated by the processing circuit 74, a GUI (Graphical User Interface) for receiving various operations from the operator, and the like. For example, the display 72 is a liquid crystal display or a CRT (Cathode Ray Tube) display. The display 72 is an example of a display unit. Further, the display 72 may be provided on the CT gantry 30. The display 72 may be a desktop type or a tablet terminal or the like capable of wireless communication with the console device 70 main body.

The input interface 73 performs input of subject information, setting of X-ray conditions, input of various command signals, and the like. The subject information includes, for example, the subject ID, the subject name, the date of birth, the age, the weight, the sex, and the examination site. The subject information may include the height of the subject. The input interface 73 is, for example, a trackball for instructing the movement of the C-arm 14, setting a region of interest (ROI), a switch button, a mouse, a keyboard, a touch pad for performing an input operation by touching an operation surface, and It is realized by a touch panel display or the like in which a display screen and a touch pad are integrated. The input interface 73 is connected to the processing circuit 74, converts an input operation received from the operator into an electric signal, and outputs the electric signal to the processing circuit 74. The input interface 73 may be provided in the CT gantry 30. Further, the input interface 73 may be configured by a tablet terminal or the like that can wirelessly communicate with the console device 70 main body. Further, in the present specification, the input interface 73 is not limited to the one including physical operation parts such as a mouse and a keyboard. For example, the input interface 73 also includes an electric signal processing circuit that receives an electric signal corresponding to an input operation from an external input device provided separately from the device and outputs the electric signal to the processing circuit 74. ..

The processing circuit 74 is a processor that realizes a system control function 741, a drive control function 742, a shooting control function 743, an image processing function 744, and a display control function 746 corresponding to the program by calling and executing the program in the memory 71. is there. Note that, in FIG. 1, the system control function 741, the drive control function 742, the photographing control function 743, the image processing function 744, the acquisition function 745, and the display control function 746 are described as being realized by the single processing circuit 74. However, a plurality of independent processors may be combined to form a processing circuit, and each processor may realize a function by executing a program. A system control function 741, a drive control function 742, a shooting control function 743, an image processing function 744, an acquisition function 745, and a display control function 746 are a system control circuit, a drive control circuit, an imaging control circuit, an image processing circuit, and an acquisition processing circuit, respectively. It may be called a circuit and a display control circuit, or may be implemented as a separate hardware circuit.

The system control function 741 temporarily stores information such as an operator command signal input from the input interface 73 and various initial setting conditions, and then transmits the information to each processing function of the processing circuit 74.

The drive control function 742 uses, for example, the information regarding the drive of the CT gantry 30, the C arm 14, and the top plate 53 input from the input interface 73, to the CT control device 35, the C arm drive device 142, and the bed drive device 52. Take control. For example, the drive control function 742 controls movement and rotation of the angio gantry 10, movement and rotation and tilt of the CT gantry 30, and movement and tilt of the bed apparatus 50. Further, for example, the drive control function 742 may move the top plate 53 from the CT image capturing position and place the subject P at the image capturing position of the angio image by the angio gantry 10 disposed near the support frame 54. .. In this case, the drive control function 742 tilts the top plate 53 so as to reproduce the tilt due to the deflection of the top plate 53 based on the information regarding the deflection of the top plate 53 at the imaging position of the CT image. The drive control function 742 may change the height of the top plate 53 in addition to tilting the top plate 53. The tilt and height of the top plate 53 may be changed in parallel or in series. In the opposite case, the drive control function 742 may move the top plate 53 from the imaging position of the angio image to place the subject P at the imaging position of the CT image. In this case, the top plate 53 is tilted so that the top plate 53 is in the horizontal state based on the information about the deflection of the top plate 53 based on the movement amount of the top plate 53 and the weight of the subject P. Similarly, the drive control function 742 may change the height of the top plate 53 in addition to tilting the top plate 53. The tilt and height of the top plate 53 may be changed in parallel or in series. Further, the drive control function 742 performs interference control based on the set interference region so as to avoid contact between the angiogantry 10 and the subject P. The drive control function 742 is an example of a top control unit.

The imaging control function 743, for example, reads information from the system control function 741 and controls X-ray conditions such as tube voltage, tube current, and irradiation time in the high voltage generator 11. The X-ray condition may include a product of the tube current and the irradiation time (mAs).

For CT imaging, the image processing function 744, for example, uses data obtained by subjecting the detection data in the memory 71 to preprocessing such as logarithmic conversion processing, offset correction processing, interchannel sensitivity correction processing, and beam hardening correction. To generate. The data before the preprocessing (detection data) and the data after the preprocessing may be collectively referred to as projection data. The image processing function 744 also performs reconstruction processing using the filtered back projection method, the successive approximation reconstruction method, or the like on the projection data generated by the preprocessing to generate CT image data. Further, the image processing function 744 converts the generated CT image data into tomographic image data or three-dimensional image data of an arbitrary section by a known method based on an input operation received from the operator via the input interface 73. To do. That is, the image processing function 744 generates two-dimensional CT image data based on the projection data indicating the intensity distribution of the X-rays transmitted through the subject P, and the two-dimensional CT image data is three-dimensional as a three-dimensional medical image. Convert to CT image data or tomographic image data. As known methods, for example, volume rendering, surface volume rendering, pixel value projection processing, MPR (Multi-Planer Reconstruction) processing, and CPR (Curved MPR) processing can be appropriately used. The image processing function 744 can also generate a CT positioning image based on the detection data.

On the other hand, for angio imaging, the image processing function 744 performs image processing such as filtering processing on projection data in the memory 71 to generate angio image data, and stores the angio image data in the memory 71. Further, the image processing function 744 performs composition processing, subtraction (subtraction) processing, and the like on the obtained plural angio image data, and stores the obtained angio image data in the memory 71.

On the other hand, the image processing function 744 can also perform a fusion process based on a CT image and an angio image, a processing process, and the like.

The acquisition function 745 captures the CT image based on the CT image obtained by imaging the subject P with the CT gantry 30 having the opening 30a into which the top plate 53 pulled out of the support frame 54 and inserted is inserted. Information on the deflection of the top plate 53 at the position is acquired. For example, the acquisition function 745 determines the angle between the horizontal direction and the direction of the straight line fitted to the surface (not shown) of the top plate 53 in the CT image or to the contour of the subject P on the top plate side. You may acquire as information regarding the bending|deflection of the top 53 in the imaging position of CT image. Further, the acquisition function 745 is pulled out from the support frame 54 from the position where the angio image is picked up by the angio gantry 10 arranged near the support frame 54 that movably supports the top plate 53 on which the subject P is placed. The top plate at the CT image capturing position is based on the amount of movement of the top plate to the CT image capturing position by the CT gantry 30 having the opening 30a into which the moved top plate 53 is inserted and the weight of the subject P. Acquire information about the deflection of 53. The acquisition function 745 is an example of an acquisition unit.

The display control function 746 performs, for example, control of reading a signal from the system control function 741 to obtain desired medical image data from the memory 71 and displaying it on the display 72.

Next, the operation of the angio-CT apparatus configured as described above will be described with reference to the flowcharts of FIGS. 5 and 8 and the schematic diagrams of FIGS. 6, 7, and 9 to 11. The following description will be made with reference to FIGS. 5 to 7 regarding the operation in the case of capturing an angio image after capturing a CT image. Next, as a reverse case, the operation in the case of capturing the CT image after capturing the angio image will be described with reference to FIGS. 8 to 11.

[When capturing angio image after capturing CT image: ST1 to ST8]
In step ST1, the processing circuit 74 of the angio CT apparatus 1 controls the CT gantry 30 and the angio gantry 10 so as to move along the rails r1 and r2 according to the operation of the input interface 73 by the operator. As a result, the angio gantry 10 is arranged near the support frame 54 of the bed apparatus 50, as shown in FIG. The CT gantry 30 is arranged at a position where the top plate 53 pulled out from the support frame 54 can be inserted into the opening 30a.

After step ST1 is completed, in step ST2, the processing circuit 74 pulls out the top plate 53 on which the subject is placed from the support frame 54 and moves the subject to the CT image capturing position, as shown in FIG. Place P. At this time, the top plate 53 is bent due to gravity, and the tip of the top plate 53 is lowered. Along with this, the subject P inclines in the direction in which the head is lowered.

After step ST2, in step ST3, the processing circuit 74 controls the CT gantry 30, performs the positioning scan, and then executes the CT imaging. As a result, a CT image obtained by photographing the tilted subject as shown in FIG. 3 is obtained.

After step ST3, in step ST4, the processing circuit 74 acquires, based on the CT image, information regarding the deflection of the top plate 53 at the imaging position of the CT image.

After step ST4, in step ST5, the processing circuit 74 moves the top plate 53 from the imaging position of the CT image and causes the angio gantry 10 arranged near the support frame 54, as shown in FIG. 7A. The subject P is placed at the imaging position of the angio image. In addition, when only step ST5 is executed, as shown in FIG. 7B, since the top plate 53 does not bend at the imaging position of the angio image, the top plate 53 and the subject P become horizontal.

After step ST5, in step ST6, the processing circuit 74 reproduces the inclination due to the bending of the table 53 as shown in FIG. 7A based on the information about the bending of the table 53 at the imaging position of the CT image. The top plate 53 is tilted so as to do so. Note that steps ST5 and ST6 may be executed in parallel or serially. At this time, the processing circuit 74 may change the height of the top plate 53 in addition to tilting the top plate 53. In any case, the subject P inclines in the direction in which the head is lowered.

After step ST6, in step ST7, the processing circuit 74 controls the angio gantry 10 to execute angio imaging. As a result, an angio image of the tilted subject is obtained.

After step ST7, in step ST8, the processing circuit 74 executes image fusion or image processing using the CT image and the angio image of the subject P inclined at the same angle.

[When CT image is captured after capturing angio image: ST11 to ST18]
In step ST11, the processing circuit 74 of the angio CT apparatus 1 arranges the angio gantry 10 and the CT gantry 30 as shown in FIG. 2, as in step ST1 described above.

After step ST11 is completed, in step ST12, the processing circuit 74 moves the top plate 53 on which the subject P is placed, and places the subject P at the imaging position of the angio image, as shown in FIG. At this time, the top plate 53 is supported by the support frame 54 and becomes horizontal. Similarly, the subject P on the top plate 53 also becomes horizontal.

After step ST12, in step ST13, the processing circuit 74 controls the angio gantry 10 to execute angio imaging. As a result, an angio image of the subject P in the horizontal state is obtained.

After the end of step ST13, in step ST14, the processing circuit 74 pulls out the top plate 53 on which the subject P is placed from the support frame 54 and moves it, as shown in FIG. A sample P is placed. At this time, the top plate 53 is bent due to gravity, and the tip of the top plate 53 is lowered. Along with this, the subject P inclines in the direction in which the head is lowered.

After step ST14, in step ST15, the processing circuit 74 determines the CT image capturing position based on the amount of movement of the tabletop 53 from the angio image capturing position to the CT image capturing position and the weight of the subject P. The information regarding the deflection of the top plate 53 at is acquired. Specifically, the processing circuit 74 reads the tilt angle related to the deflection of the top plate 53 from the patient load table 71a in the memory 71 based on the moving amount of the top plate 53 and the weight of the subject P. Note that this tilt angle may be referred to as a top plate sag angle.

After step ST15, in step ST16, the processing circuit 74 sets the tabletop 53 to the horizontal state as shown in FIG. 11 based on the information about the deflection of the tabletop 53 at the CT image capturing position. Tilt 53. The processing circuit 74 may change the height of the top plate 53 in addition to tilting the top plate 53. In any case, the subject P becomes horizontal.

After step ST16, in step ST17, the processing circuit 74 controls the CT gantry 30 to perform the positioning scan and then the CT imaging. As a result, a CT image of the subject P in the horizontal state is obtained.

After step ST17, in step ST18, the processing circuit 74 executes image fusion or image processing using the CT image and the angio image of the subject P tilted at the same angle. Here, the image fusion may be, for example, a process of aligning and superimposing the angio image and the CT image. Further, as the image processing, for example, a process of aligning the angio image and the CT image and performing some processing can be applied. As some kind of processing, for example, a processing of detecting the difference between the two images aligned and deleting or reducing the specific region from the detection result may be performed. The specific region may be, for example, a bone region or some noise. The noise may be an artifact.

As described above, according to the first embodiment, the object to be examined is the CT gantry having the opening into which the moved tabletop is pulled out from the support frame that movably supports the tabletop on which the object is placed. Based on the CT image obtained by capturing the image of, the information regarding the deflection of the top at the imaging position of the CT image is acquired. Further, when the subject is placed at the imaging position of the angio image by the angio gantry arranged near the support frame by moving the top plate from the CT image capturing position, the deflection of the top plate is caused based on the information. Tilt the top plate to reproduce the tilt. Therefore, when the top plate is moved and the angio imaging and the CT imaging are performed alternately, the difference in the inclination of the top plate can be reduced. Supplementally, it is possible to reduce the difference in the inclination of the top plate with reference to the inclination of the top plate during CT imaging.

Further, by reducing the difference in the inclination of the top plate, when image fusion or image processing is performed using the angio image and the CT image, a difference occurs due to the influence of gravity with respect to the position of the organ or the blood flow. Therefore, it is possible to reduce the deviation between the images. Supplementally, if the tilt of the top plate is different between the CT image and the angio image, the position of the organ or the like will be different between the two images due to the influence of gravity, so simply performing image processing such as rotation and superimposing them. Even if the images are created, a gap remains between the images. On the other hand, in the first embodiment, by reducing the difference in the inclination of the top plate, the deviation between the images can be reduced as described above.

Further, according to the first embodiment, in addition to tilting the top plate, the height of the top plate may be changed. In this case, the rotation center of the deflection of the top plate and the rotation center of the tilt of the top plate can be matched to prevent or reduce the deviation between the enlargement ratio of the CT image and the enlargement ratio of the angio image.

In addition, according to the first embodiment, the object is pulled out from the support frame from the imaging position of the angio image by the angio gantry arranged near the support frame that movably supports the top plate on which the subject is placed. Based on the movement amount of the top plate to the CT image capturing position by the CT gantry having an opening into which the moved top plate is inserted and the weight of the subject, information regarding the deflection of the top plate at the CT image capturing position is obtained. get. In addition, when the top plate is moved from the imaging position of the angio image and the subject is placed at the imaging position of the CT image, the top plate is tilted based on the information so that the top plate is in a horizontal state. Therefore, when the top plate is moved and the angio imaging and the CT imaging are performed alternately, the difference in the inclination of the top plate can be reduced. Supplementally, it is possible to reduce the difference in the inclination of the top with reference to the inclination of the top during imaging of angio. Further, this makes it possible to reduce the difference in the inclination of the top plate in both the CT imaging and the angio imaging.

(First modification)
Next, the angio CT apparatus according to the first modified example of the first embodiment will be described. In the following description, the same parts as those in the above-mentioned drawings are designated by the same reference numerals, detailed description thereof will be omitted, and mainly different parts will be described. This also applies to the following modifications and embodiments.

The first modified example is intended to reduce an error in information regarding the deflection of the top plate 53, and has a configuration in which an inclination sensor 54a is added to a support frame 54 as shown in FIG.

Here, the tilt sensor 54a is used to adjust the support frame 54 to the absolute horizontal level, and measures the difference between the tilt of the support frame 54 and the absolute horizontal level.

Further, the memory 71 stores a correction table 71b as shown in FIG. 13, instead of the patient load table 71a described above. The correction table 71b describes the movement amount of the top plate 53 and the information regarding the deflection of the top plate in association with each other. In the example shown in FIG. 13, the information regarding the deflection of the top plate is the tilt angle due to the deflection of the top plate 53. The tilt angle due to the bending of the top plate 53 may be called the tilt angle of the top plate 53 or the angle of the top plate sag. Further, the movement amount of the top plate may be referred to as a horizontal movement position of the top plate. That is, the amount of movement of the top may be represented by the horizontal movement position of the top.

Other configurations are similar to those of the first embodiment.

Next, the operation of the angio CT apparatus according to the first modification will be described. Steps ST1 to ST8 for performing angio imaging after CT imaging are as described above.

On the other hand, the operations of steps ST11 to ST18 for performing CT imaging after angio imaging are slightly different. That is, after steps ST11 to ST14 similar to the above, in step ST15, the processing circuit 74 acquires the tilt angle due to the deflection of the top plate 53 from the correction table 71b in the memory 71 based on the movement amount of the top plate 53. ..

After step ST15, in step ST16, the processing circuit 74 sets the reference of the tilt angle of the top plate 53 to the absolute horizontal level based on the measurement value of the tilt sensor 54a. After that, the processing circuit 74 tilts the top plate 53 so that the top plate 53 is in the horizontal state based on the tilt angle of the top plate 53 at the CT image capturing position. The processing circuit 74 may change the height of the top plate 53 in addition to tilting the top plate 53. In any case, the subject P becomes horizontal.

Thereafter, steps ST17 to ST18 are executed in the same manner as described above.

According to the first modification of the first embodiment as described above, the tilt sensor for measuring the absolute horizontal level is provided on the support frame, and the top plate is tilted based on the measurement value of the tilt sensor, whereby the tilt sensor The top plate can be tilted at a more accurate angle than when there is no.

(Second modified example)
The second modification is a specific example of image fusion and image processing executed by the processing circuit 74 in step ST8 or ST18. As an example of image fusion, there is a case where the 3D-CT image and the 3D-angio image are aligned and fused.

As another example of image fusion, there is a case where the 2D-CT image is aligned with the 2D-angio image to perform fusion. In this case, for example, as shown in FIG. 14, the corresponding 2D-CT image g11 is cut out from the 3D-CT image g10 at a certain cutting angle, and the 2D-CT image g11 is aligned with the 2D-angioscopic perspective image g20. Superimpose and create a superimposed image g31. Here, the cutout angle is based on the angle information of the C arm 14.

As an example of image processing, it is possible to apply processing of aligning the angio image and the CT image and performing some processing. For example, the 2D-CT image g11 described above is aligned with the 2D-angio perspective image g20, the difference between the two images is detected, and the bone region is erased from the detection result to create a processed image g32. Instead of the process of deleting the bone region, a specific region such as noise may be deleted or reduced. The noise may be an artifact.

According to the second modification of the first embodiment as described above, there are cases where a 2D-CT image cut out from a 3D-CT image based on the angle information of the C arm 14 and a 2D-angio image are used. .. In this case, in addition to the effects of the first embodiment, it is possible to reduce image shift when performing image fusion or image processing. Moreover, image artifacts can be reduced.

<Second Embodiment>
Next, the angio CT apparatus according to the second embodiment will be described.

The second embodiment is a modification of the first embodiment, and has a configuration in which an interference region is set based on a CT image when angio imaging is performed, as shown in FIG.

Accordingly, the image processing function 744 of the processing circuit 74 generates three-dimensional image data indicating the surface shape of the subject P based on the CT image of the subject captured by the CT gantry 30 in addition to the above-described functions. To do. The image processing function 744 is an example of a generation unit.

In addition to the above-mentioned function, the drive control function 742 sets an interference area for avoiding contact between the angiogantry 10 and the subject P based on the three-dimensional image data. The set interference area is used for interference control, as described above. The drive control function 742 is an example of a region setting unit. The image processing function 744 may be an example of the area setting unit instead of the drive control function 742.

Other configurations are similar to those of the first embodiment.

Next, the operation of the angio CT apparatus configured as described above will be described with reference to the flowchart of FIG. 16 and the schematic diagrams of FIGS. 17 and 18.

Now, it is assumed that steps ST1 to ST6 are executed, and the top plate 53 is tilted so as to reproduce the tilt due to the bending of the top plate 53 based on the CT image at the imaging position of the angio image, as described above.

After step ST6, steps ST7-1 to ST7-3 are sequentially executed instead of step ST7 described above. That is, in step ST7-1, the processing circuit 74 generates three-dimensional image data g2 indicating the surface shape of the subject P based on the CT image, as shown in FIG.

After step ST7-1, in step ST7-2, the processing circuit 74 sets the interference area A1 for avoiding contact between the angiogantry 10 and the subject P based on the three-dimensional image data g2. In FIG. 17, the interference region A1 is a region corresponding to the surface shape of the subject P, but is not limited to this, and may be a region in the vicinity of the subject that wraps the surface shape of the subject P. Further, the processing circuit 74 may set the interference area A1 so as to overwrite the initially set interference area A0, as shown in FIG. At this time, the processing circuit 74 may or may not compare the interference area A1 created from the three-dimensional image data g2 and the default interference area A0. For comparison, the processing circuit 74 may overwrite the interference area A1 if the created interference area A1 is larger than the initially set interference area A0. When the comparison is not performed, the processing circuit 74 may uniformly overwrite and set the newly created interference area A1. In any case, the processing circuit 74 sets the interference area A1 based on the three-dimensional image data g2 or g3 in the memory 71.

After step ST7-2, in step ST7-3, the processing circuit 74 controls the angio gantry 10 and executes angio imaging while performing the interference control based on the set interference area A1. As a result, an angio image of the tilted subject is obtained.

After step ST7-3, step ST8 is executed as described above.

According to the second embodiment described above, three-dimensional image data showing the surface shape of the subject is generated based on the CT image. Further, an interference area for avoiding contact between the angiogantry and the subject is set based on the three-dimensional image data. Therefore, in addition to the effects of the first embodiment, the X-ray detector at the tip of the C-arm can be arranged at a position closer to the surface of the subject, and a safer angio CT device can be provided.

<Third Embodiment>
Next, an angio CT apparatus according to the third embodiment will be described.

The third embodiment is a modified example of the first or second embodiment, and has a configuration in which conditions for angio imaging are set based on information at the time of CT imaging.

Along with this, the imaging control function 743 of the processing circuit 74 sets the X-ray condition for imaging an angio image based on the CT image in addition to the above-mentioned function.

For example, the imaging control function 743 is displaying a plurality of MPR (Multi-Planar Reformat) images generated from CT volume data forming a three-dimensional CT image on the display 72, and rotates DSA imaging according to the operation of the operator. The center point (isocenter) of the region of interest in is designated and the position information of the isocenter is embedded in the CT volume data. The CT volume data is data having CT value distribution information in a three-dimensional space. Further, the operator refers to the plurality of MPR images or the three-dimensional CT images and embeds the region information of the target region (region of interest) of the rotational DSA imaging in the CT volume data. The isocenter position information and the ROI position information are embedded, for example, as header information of CT volume data. DSA is an abbreviation for Digital Subtraction Angiography.

Further, the imaging control function 743 arranges the CT volume data at a position (coordinates) where a projection image similar to the angio image generated in the position information of the top plate 53 and the C arm 14 is generated, thereby performing alignment. Do. For example, alignment is performed by arranging CT volume data based on the characteristic points of a specific organ (liver, heart, brain, etc.) in the region of interest. Further, the imaging control function 743 wants to perform imaging based on the amount of deviation between the desired isocenter (the point where the isocenter embedded in the CT volume data is projected on the simulated X-ray image) and the isocenter of the angiogantry 10. The position of the subject P is adjusted by adjusting the positions of the top plate 53 and the C arm 14 so that the coordinates of the isocenter and the isocenter of the angiogantry 10 match.

Then, the imaging control function 743 transfers the CT values of the CT volume data aligned with respect to the angio imaging coordinate system from the X-ray generation unit 12 at the imaging position to the position (x , Y, z) is replaced with the X-ray absorption value when projected, and the replaced X-ray absorption value is corrected based on the set X-ray condition. Then, the imaging control function 743 integrates the corrected X-ray absorption value to obtain X-ray image information when the CT volume data is projected at the position (x, y, z) of the X-ray detector 13. To calculate. By performing this for all the coordinates of the detection surface of the X-ray detector 13, simulated X-ray image data is generated. Further, the imaging control function 743 reads out the position information of the top plate 53 and the C arm 14 and the set X-ray condition, and simulates each rotational imaging angle at which rotational imaging is performed (for example, every 10°). X-ray image data is generated. Thereafter, the imaging control function 743 sets the dose of X-rays emitted from the X-ray generation unit 12 so that each of the generated simulated X-ray images for each rotation imaging angle is displayed on the display 72 with an appropriate brightness. “Tube voltage (unit: kV)” and “product of tube current and X-ray irradiation seconds (unit: mAs)” for correction are calculated. That is, the imaging control function 743 sets the FOV (Field of View) and the SID (Source Image Distance), and again generates simulated X-ray image data for each rotation imaging angle for one rotation every 10°. The brightness gain is calculated so that the brightness of the imaging range (region of interest) is appropriate in the simulated X-ray image on the display 72. Further, the imaging control function 743 calculates and sets X-ray conditions for realizing each calculated brightness gain. Note that the imaging control function 743 is not limited to this, and performs CT processing by calculating the position and body shape information of the subject P at the imaging position of the angio image from the X-ray condition and bed position information at the imaging position of the CT image. It may be used as information for converting the X-ray condition of the above into the X-ray condition of angio imaging. The shooting control function 743 is an example of a condition setting unit.

Other configurations are similar to those of the first or second embodiment.

Next, the operation of the angio CT apparatus configured as described above will be described with reference to the flowchart of FIG. 19 and the schematic diagram of FIG.

Now, it is assumed that steps ST1 to ST6 are executed, and the top plate 53 is tilted so as to reproduce the tilt due to the bending of the top plate 53 based on the CT image at the imaging position of the angio image, as described above.

After step ST6, steps ST7b-1 and ST7b-2 are sequentially executed in place of step ST7 or steps ST7-1 to ST7-3 described above. That is, in step ST7b-1, the processing circuit 74 sets an X-ray condition for capturing an angio image based on the CT image. For example, the processing circuit 74 causes the X-ray image information when the CT volume data aligned with the coordinate system for angio imaging is projected at the position (x, y, z) of the X-ray detector 13. To calculate. By performing this for all the coordinates of the detection surface of the X-ray detector 13, simulated X-ray image data is generated. Further, the imaging control function 743 reads the position information of the top plate 53 and the C arm 14 and the set X-ray condition, and generates simulated X-ray image data for each rotational imaging angle at which rotational imaging is performed. .. Then, the imaging control function 743 causes the generated simulated X-ray images for each rotational imaging angle to be displayed on the display 72 with an appropriate brightness so that the "tube voltage" and the "tube current and X-rays" under the X-ray conditions are displayed. The product of the line irradiation seconds" is calculated. For example, in the processing circuit 74, as shown in FIG. 20, the X-ray condition for realizing the appropriate “luminance gain: 1.0” of “RAO/LAO” is “80 kV, 100 mAs”, and “RAO”. The X-ray condition for realizing the appropriate "luminance gain: 0.8" is "80 kV, 80 mAs", and the X-ray conditions in all the simulated X-ray images are calculated. Further, the processing circuit 74 sets the X-ray condition at each rotation imaging angle. “RAO” is an abbreviation for “right anterior oblique”. “LAO” is an abbreviation for “left anterior oblique”.

After step ST7b-1, in step ST7b-2, the processing circuit 74 controls the angio gantry 10 based on the set X-ray condition, and executes angio imaging. For example, when the processing circuit 74 receives a rotation DSA imaging start request from the operator via the input interface 73, the processing arm 74 adjusts the C arm 14 adjusted to an appropriate position to the top plate 53 adjusted to an appropriate angle. Rotation is performed around the upper subject P, and X-rays are emitted from the X-ray generation unit 12 based on the set X-ray condition for each rotation imaging angle, and rotation DSA imaging is executed. Note that the angio imaging is not limited to this, and may be X-ray fluoroscopic imaging or another method. In any case, angio imaging is executed based on the set X-ray condition.

After step ST7b-2, step ST8 is executed as described above.

According to the third embodiment as described above, the X-ray condition for capturing the angio image is set based on the X-ray condition when capturing the CT image and the CT image. Therefore, in addition to the effect of the first or second embodiment, when the CT imaging is switched to the angio imaging, the test exposure for setting the X-ray condition is not necessary, and the exposure is reduced. You can In addition, since test exposure is unnecessary, inspection efficiency can be improved.

<Fourth Embodiment>
Next, an angio CT apparatus according to the fourth embodiment will be described.

The fourth embodiment is a modification of each of the first to third embodiments and has a configuration in which the CT image is corrected and displayed so that the subject is in a horizontal state.

Along with this, the image processing function 744 of the processing circuit 74 corrects the CT image based on the CT image so that the subject P in the CT image is in a horizontal state in addition to the above-described function. Specifically, for example, the image processing function 744 is based on the angle formed between the horizontal direction and the direction of a straight line fitted to the surface of the top plate 53 in the CT image or to the contour of the subject P on the top plate side. The CT image may be rotated so that the straight line becomes horizontal. The center of rotation when the CT image is rotated may be the imaging position of the angio image that is separated from the imaging position of the CT image by the distance between the CT gantry 30 and the angio gantry 10, or may be an arbitrary point in the CT image. Good. The image processing function 744 also creates a superimposed image by superimposing the corrected CT image on the angio image based on the amount of movement of the top from the CT image capturing position to the angio image capturing position. May be. The angio image used by the image processing function 744 (that is, the angio image obtained by imaging the subject P with the angio gantry 10) is stored in the memory 71. The image processing function 744 is an example of an image correction unit and an image superposition unit. The memory 71 is an example of a storage unit.

The display control function 746 causes the display 72 to display the corrected CT image in addition to the functions described above. Further, the display control function 746 may display the superimposed image on the display 72. The display control function 746 is an example of a display control unit.

Other configurations are similar to those of the first to third embodiments.

Next, the operation of the angio CT apparatus configured as described above will be described with reference to the flowchart of FIG. 21 and the schematic diagram of FIG. Note that the following description will be given by taking the case where it is applied to the first embodiment as an example, but it can be similarly applied to the second or third embodiment.

Now, it is assumed that steps ST1 to ST3 are executed and CT imaging is performed at the imaging position of the CT image, as described above. As a result, it is assumed that a CT image g4 obtained by photographing the tilted subject P is obtained as shown in the upper part of FIG. In order to facilitate understanding, the horizontal direction Lh1 and the direction Lt inclined by the angle θ from the horizontal direction Lh1 due to the bending of the top plate 53 are shown in the figure. However, in the actual CT image g4, these horizontal directions Lh1 are shown. And the inclined direction Lt are not overlapped.

After step ST3, steps ST4c-1 and ST4c-2 are sequentially executed instead of step ST4 described above. That is, in step ST4c-1, the processing circuit 74 acquires information regarding the deflection of the top plate 53 at the imaging position of the CT image g4 based on the CT image g4.

After step ST4c-1, in step ST4c-2, the processing circuit 74 corrects the CT image g4 based on the CT image g4 so that the subject P in the CT image g4 becomes horizontal. As a result, a corrected CT image g4c is obtained as shown in the lower part of FIG. Although the horizontal directions Lh1 and Lh2 are illustrated for ease of understanding as described above, these horizontal directions Lh1 and Lh2 are not superimposed on the actual CT image g4c. Further, the processing circuit 74 displays the corrected CT image g4c on the display 72.

After step 4c-2, similarly to the above, steps ST5 to ST7 are executed to obtain an angio image of the subject P imaged at the angio imaging position.

After step ST7, steps ST8c-1 and ST8c-2 are sequentially executed instead of step ST8 described above. That is, in step ST8c-1, the processing circuit 74 superimposes the corrected CT image g4c on the angio image based on the amount of movement of the tabletop 53 from the imaging position of the CT image g4c to the imaging position of the angio image. To create a superimposed image.

After step ST8c-1, in step ST8c-2, the processing circuit 74 causes the display 72 to display the superimposed image.

As described above, according to the fourth embodiment, the CT image is corrected so that the subject in the CT image is in the horizontal state based on the information regarding the deflection of the top plate, and the corrected CT image is obtained. Display on the display. This makes it possible to automatically display the displayed CT image in a horizontal state.

Further, according to the fourth embodiment, the CT image is corrected to the horizontal state based on the information regarding the deflection of the top plate so that the subject in the CT image is in the horizontal state. An angio image obtained by imaging the subject with an angio gantry is stored. A superimposed image is created by superimposing the corrected CT image on the angio image based on the amount of movement of the tabletop from the imaging position of the angio image to the imaging position of the CT image. The superimposed image is displayed on the display unit.

Therefore, since the horizontal state of the CT image is maintained, it is possible to simply perform the X correction when performing the shift correction operation for superimposing the CT image and the angio image for fusion display and the pixel shift operation for correcting the image artifact due to the shift. , Y-direction coordinates can be adjusted. Therefore, in the fourth embodiment, operability can be improved. On the other hand, when the CT image is tilted due to the top plate sagging, the coordinate conversion in the X and Y directions becomes complicated at the time of the operation of correcting the deviation for the fusion display and the pixel shift operation, and the adjustment is simply performed. I can't.

According to at least one embodiment described above, a subject is detected by a CT gantry having an opening into which the moved top plate is pulled out from a support frame that movably supports the top plate on which the subject is placed. Based on the CT image obtained by imaging, the information regarding the deflection of the tabletop at the imaging position of the CT image is acquired. Further, when the subject is placed at the imaging position of the angio image by the angio gantry arranged near the support frame by moving the top plate from the CT image capturing position, the deflection of the top plate is caused based on the information. Tilt the top plate to reproduce the tilt. Therefore, when the top plate is moved and the angio imaging and the CT imaging are performed alternately, the difference in the inclination of the top plate can be reduced.

The word "processor" used in the above description means, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), or an application specific integrated circuit (ASIC), a programmable logic device (for example, It means a circuit such as a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), a field programmable gate array (FPGA), etc. A processor is a memory circuit. The function is realized by reading out and executing the program stored in the memory. Instead of storing the program in the memory circuit, the program may be directly incorporated in the circuit of the processor. The functions are realized by reading and executing a program embedded in the circuit.Note that each processor of the present embodiment is not limited to a case where each processor is configured as a single circuit, and a plurality of independent circuits are provided. The functions may be implemented by combining them into a single processor, or the functions may be implemented by integrating the plurality of constituent elements in FIG. ..

Although some embodiments of the present invention have been described, these embodiments are presented as examples 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 modifications thereof are included in the invention described in the claims and equivalents thereof as well as included in the scope and the gist of the invention.

DESCRIPTION OF SYMBOLS 1 Angio CT device 10 Angio gantry 11 High voltage generator 12 X-ray generator 13, 32 X-ray detector 14 C arm 14a Holding part 14b Support arm 141 State detector 142 C arm drive device 30 CT Gantry 30a Opening 31 X-ray Tube 33 Rotating frame 34 X-ray high voltage device 35 CT controller 36 Wedge 37 Collimator 38 DAS
50 Bed Device 51 Base Bed 52 Bed Driving Device 53 Top Plate 54 Support Frame 54a Tilt Sensor 70 Console Device 71 Memory 71a Patient Load Table 71b Correction Table 72 Display 73 Input Interface 74 Processing Circuit 741 System Control Function 742 Drive Control Function 743 Imaging Control Function 744 Image processing function 745 Acquisition function 746 Display control function A1, A0 Interference area g1, g4 CT image g2, g3 Three-dimensional image data Lh, Lh1, Lh2 Horizontal direction Lt Inclined direction r1, r2 Rail

Claims (7)

Based on a CT image obtained by imaging the subject with a CT gantry having an opening into which the moved top plate is movably supported by a support frame on which the subject is placed. An acquisition unit that acquires information about the deflection of the top at the imaging position of the CT image,
When the subject is placed at the imaging position of the angio image by the angio gantry arranged near the support frame by moving the top plate from the imaging position of the CT image, the top plate is based on the information. An angiography CT apparatus comprising: a top control unit that tilts the top so as to reproduce the inclination caused by the bending of the top. The angio-CT apparatus according to claim 1, wherein the top control unit changes the height of the top in addition to tilting the top. A generation unit that generates three-dimensional image data indicating the surface shape of the subject based on the CT image;
The angio CT apparatus according to claim 1 or 2, further comprising: an area setting unit that sets an interference area for avoiding contact between the angiogantry and the subject based on the three-dimensional image data. The angio CT apparatus according to claim 1, further comprising a condition setting unit that sets an X-ray condition for capturing the angio image based on the CT image. An image correction unit and a display control unit are provided,
The image correction unit corrects the CT image based on the CT image so that the subject in the CT image becomes horizontal.
The angio CT apparatus according to claim 1, wherein the display control unit causes the display unit to display the corrected CT image. An image correction unit, a storage unit, an image superposition unit, and a display control unit are provided,
The image correction unit corrects the CT image in a horizontal state based on the CT image so that the subject in the CT image is in a horizontal state,
The storage unit stores an angio image obtained by imaging the subject with the angio gantry,
The image superimposing unit superimposes the corrected CT image on the angio image based on the amount of movement of the top from the CT image capturing position to the angio image capturing position to form a superimposed image. make,
The angio CT apparatus according to claim 1, wherein the display control unit causes the display unit to display the superimposed image. From the imaging position of the angio image by the angio gantry arranged near the support frame that movably supports the top plate on which the subject is placed, open the opening through which the top plate pulled out from the support frame and inserted is inserted. An acquisition unit that acquires information regarding the deflection of the tabletop at the imaging position of the CT image, based on the amount of movement of the tabletop to the imaging position of the CT image by the CT gantry and the weight of the subject.
When the top plate is moved from the imaging position of the angio image to place the subject at the imaging position of the CT image, based on the information, the top plate is set so as to be in a horizontal state. An angio CT device including a top plate control unit for tilting.