X-ray CT scanner, control method using the X-ray CT scanner, and program

Abstract

The goal is to reduce the risk of contact between the scanner and the subject during seated imaging. [Solution] The X-ray CT apparatus of the embodiment comprises a scanner unit, a support unit, an acquisition unit, a setting unit, and an operation control unit. The scanner unit has an imaging system. The support unit supports the scanner unit and moves the scanner unit in the vertical direction. The acquisition unit acquires subject information, including the subject's imaging posture. When the imaging posture is seated, the setting unit sets a first section in which the descent speed, which represents the speed at which the scanner unit moves vertically downward, is less than or equal to a first speed, and a second section in which the descent speed is less than or equal to a second speed. The operation control unit controls the descent speed based on the set first and second sections and the vertical position of the scanner unit. The first speed is greater than the second speed, and the first section is a section vertically above the second section.

Description

Technical Field

[0001] The embodiments disclosed in this specification and the drawings relate to an X-ray CT apparatus, a control method for the X-ray CT apparatus, and a program.

Background Art

[0002] Conventionally, an X-ray Computed Tomography (CT) apparatus having a stand that supports a scanner into which a subject is inserted is known. In such an X-ray CT apparatus, the scanner is tilted or moved vertically by being supported by the stand. Thereby, the X-ray CT apparatus can scan a subject standing upright. Further, such an X-ray CT apparatus can also scan a seated subject by using a chair or a wheelchair.

[0003] By the way, medical workers such as technicians and doctors have a desire to image as wide a range as possible of the subject's body (for example, up to the lung field in seated imaging). However, when performing seated imaging, depending on the build of the subject, the feet may be located outside the opening of the scanner in the horizontal direction that is perpendicular to the vertical direction and horizontal with respect to the floor surface.

[0004] In this case, if the scanner is operated at full stroke, there is a possibility that the scanner and the vicinity of the subject's knee may interfere when the scanner moves up and down. Also, when the scanner descends rapidly near the subject's knee, the subject may be worried that the scanner and the vicinity of their own knee may come into contact.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The problem that the embodiments disclosed herein and in the drawings aim to solve is to reduce the risk of contact between the scanner and the subject during seated imaging. However, the problems that the embodiments disclosed herein and in the drawings aim to solve are not limited to the above problem. Problems corresponding to the effects of each configuration shown in the embodiments described later can also be positioned as other problems. [Means for solving the problem]

[0007] The X-ray CT apparatus of this embodiment comprises a scanner unit, a support unit, an acquisition unit, a setting unit, and an operation control unit. The scanner unit has an imaging system. The support unit supports the scanner unit and moves the scanner unit in the vertical direction. The acquisition unit acquires subject information, including the subject's imaging posture. When the imaging posture is seated, the setting unit sets a first section in which the descent speed, which represents the speed at which the scanner unit moves vertically downward, is less than or equal to a first speed, and a second section in which the descent speed is less than or equal to a second speed. The operation control unit controls the descent speed based on the set first and second sections and the vertical position of the scanner unit. Furthermore, the first speed is greater than the second speed, and the first section is a section vertically above the second section. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a block diagram showing an example of the configuration of an X-ray CT apparatus according to this embodiment. [Figure 2] Figure 2 shows an example of the external appearance of an X-ray CT apparatus according to this embodiment. [Figure 3] Figure 3 is a perspective view showing an example of an X-ray CT apparatus for examining a subject in a supine position according to the embodiment. [Figure 4] Figure 4 is a perspective view showing an example of an X-ray CT scanner for examining a standing subject according to the embodiment. [Figure 5] Figure 5 shows an example of photographing a subject seated in a wheelchair according to the embodiment. [Figure 6]Figure 6 illustrates an example of the process for setting the descent velocity according to the embodiment. [Figure 7] Figure 7 shows an example of a display screen showing the operating speed of a scanner according to the embodiment. [Figure 8] Figure 8 is a flowchart showing an example of a process performed by the X-ray CT apparatus according to this embodiment. [Modes for carrying out the invention]

[0009] The following describes the embodiment of the X-ray CT apparatus, the control method using the X-ray CT apparatus, and the program with reference to the drawings. The X-ray CT apparatus is a medical device comprising a scanner provided with an opening into which a subject can be inserted, a scanner drive device that moves the scanner relative to the subject, and a support on which the subject is placed. The scanner drive device can move the scanner up, down, left, right, and diagonally, and can scan whether the subject is lying down or standing.

[0010] Figure 1 is a block diagram showing an example of the configuration of an X-ray CT apparatus 1 according to an embodiment. Figure 2 is a diagram showing an example of the external appearance of the X-ray CT apparatus 1.

[0011] The X-ray CT scanner 1 includes, for example, a gantry unit 10, a patient bed unit 30, and a console unit 40. In Figure 1, for illustrative purposes, both a view of the gantry unit 10 from the Z-axis direction and a view from the X-axis direction are shown, but in reality, there is only one gantry unit 10.

[0012] In this embodiment, in a non-tilted state, the rotation axis of the rotating frame 17 or the longitudinal direction of the top plate 33 of the bed device 30 along the horizontal direction is defined as the Z-axis direction (front-to-back direction), the axis perpendicular to the Z-axis direction and horizontal to the floor surface is defined as the X-axis direction (circumferential direction), and the direction perpendicular to the Z-axis direction and perpendicular to the floor surface is defined as the Y-axis direction (up-down direction).

[0013] The gantry unit 10 in the X-ray CT scanner 1 includes, for example, a scanner 20, a scanner drive unit 22, and a control unit 24. The scanner 20 is supported by the scanner drive unit 22. The scanner drive unit 22 moves the scanner 20 in the up, down, left, and right directions, and also tilts the scanner 20 to switch its orientation. The control unit 24 controls the operation of the scanner drive unit 22.

[0014] Scanner 20 is an example of a scanner unit. Scanner 20 includes an X-ray tube 11, a wedge 12, a collimator 13, an X-ray high-voltage device 14, an X-ray detector 15, a data acquisition system (hereinafter referred to as DAS: Data Acquisition System) 16, a rotating frame 17, and a cover 18. The X-ray tube 11, wedge 12, collimator 13, X-ray high-voltage device 14, X-ray detector 15, DAS 16, and rotating frame 17 are housed within the cover 18.

[0015] The X-ray tube 11 generates X-rays by irradiating thermionic electrons from the cathode (filament) to the anode (target) when a high voltage is applied from the X-ray high-voltage device 14. The X-ray tube 11 irradiates the subject P with X-rays. The X-ray tube 11 includes a vacuum tube. For example, the X-ray tube 11 is a rotating anode type X-ray tube that generates X-rays by irradiating a rotating anode with thermionic electrons. The X-ray tube 11 is an example of an irradiation unit.

[0016] The wedge 12 is a filter used to adjust the amount of X-rays (radiation dose) irradiated from the X-ray tube 11 to the subject (image subject) P. The wedge 12 attenuates the X-rays that pass through it so that the distribution of the X-ray dose irradiated from the X-ray tube 11 to the subject P becomes a predetermined distribution. The wedge 12 is also called a wedge filter or bow-tie filter. The wedge 12 is made of aluminum that has been processed to have a predetermined target angle and a predetermined thickness, for example.

[0017] The collimator 13 is a mechanism for narrowing down the irradiation range of the X-rays that have passed through the wedge 12. The collimator 13, for example, forms a slit by combining a plurality of lead plates to narrow down the irradiation range of the X-rays. The collimator 13 may also be referred to as an X-ray aperture. The collimator 13 may be an active collimator whose narrowing range is mechanically drivable.

[0018] The X-ray high voltage device 14 has, for example, a high voltage generator and an X-ray control device. The high voltage generator has an electric circuit including a transformer (transformer) and a rectifier, etc., and generates a high voltage to be applied to the X-ray tube 11. The X-ray control device controls the output voltage of the high voltage generator according to the amount of X-rays to be generated by the X-ray tube 11.

[0019] The high voltage generator may perform voltage boosting by the above-described transformer, or may perform voltage boosting by an inverter. The X-ray high voltage device 14 may be provided on the rotating frame 17, or may be provided on the side of the fixed frame (not shown) of the gantry device 10.

[0020] The X-ray detector 15 detects the intensity of the X-rays generated by the X-ray tube 11 and incident after passing through the subject P. The X-ray detector 15 outputs an electrical signal (which may also be an optical signal, etc.) corresponding to the detected intensity of the X-rays to the DAS 16. The X-ray detector 15 has, for example, a plurality of X-ray detection element arrays. Each of the plurality of X-ray detection element arrays has a plurality of X-ray detection elements arranged in the channel direction along an arc centered on the focal point of the X-ray tube 11. The plurality of X-ray detection element arrays are arranged in the slice direction (column direction, row direction). <​​​​​​​​ The grid is positioned on the X-ray incident surface of the scintillator array and has an X-ray shielding plate that absorbs scattered X-rays. The grid is sometimes also called a collimator (one-dimensional collimator or two-dimensional collimator).

[0024] The optical sensor array includes, for example, optical sensors such as photomultipliers (PMTs). The optical sensor array outputs an electrical signal corresponding to the amount of light emitted by the scintillator. The X-ray detector 15 may be a direct conversion type detector having a semiconductor element that converts incident X-rays into an electrical signal.

[0025] The DAS16 includes, for example, an amplifier and an A / D converter. The amplifier performs amplification processing on the electrical signals output by each X-ray detection element of the X-ray detector 15. The A / D converter converts the electrical signals into digital signals. The DAS16 outputs detection data based on the digital signals to the console device 40.

[0026] The rotating frame 17 is an annular member that supports the X-ray tube 11, wedge 12, and collimator 13 in opposition to the X-ray detector 15. The rotating frame 17 is supported by a fixed frame so as to be rotatable around the subject P introduced inside. The rotating frame 17 further supports the DAS 16.

[0027] The detection data output by DAS16 is transmitted via optical communication from a transmitter having a light-emitting diode (LED) on the rotating frame 17 to a receiver having a photodiode on the non-rotating part (e.g., the fixed frame) of the mounting device 10, and is then transferred by the receiver to the console device 40.

[0028] Furthermore, the method for transmitting detection data from the rotating frame 17 to the non-rotating part is not limited to the optical communication method described above; any non-contact transmission method may be used. The rotating frame 17 is not limited to an annular member, but may be an arm-like member, as long as it can support and rotate the X-ray tube 11 or the like.

[0029] The cover 18 is provided with a central opening 19. The central opening 19 is an opening into which the subject P is inserted. A rotating frame 17 provided inside the cover 18 is positioned inside the cover 18, surrounding the central opening 19. The rotating frame 17 rotates around the central opening 19.

[0030] The X-ray CT apparatus 1 is, for example, a Rotate / Rotate-Type X-ray CT apparatus (third-generation CT) in which both the X-ray tube 11 and the X-ray detector 15 are supported by a rotating frame 17 and rotate around the subject P. However, it is not limited to this, and may also be a Stationary / Rotate-Type X-ray CT apparatus (fourth-generation CT) in which a plurality of X-ray detection elements arranged in a ring shape are fixed to a fixed frame and the X-ray tube 11 rotates around the subject P.

[0031] The scanner drive unit 22 includes, for example, a base 101, a horizontal movement device 102, a support column 103, a rail 104, a slider 105, and a tilt mechanism 106. The base 101 includes, for example, a linear support structure extending in the horizontal direction. The base 101 is fixed to, for example, the floor surface of the examination room by bolts or the like.

[0032] The horizontal movement device 102 is mounted on the base 101, and a support column 103 is mounted on the horizontal movement device 102 in an upright position. The support column 103 is, for example, a member that extends in the vertical direction. Based on the control of the control device 24, the horizontal movement device 102 moves the mounted support column 103 in the horizontal direction.

[0033] A rail 104 is attached to the support column 103. The rail 104 is positioned along the extension direction (vertical direction) of the support column 103. A slider 105 is attached to the rail 104. The slider 105 is movable along the rail 104 based on the control of the control device 24.

[0034] A tilt mechanism 106 is attached to the slider 105, and a scanner 20 is attached to the tilt mechanism 106. The tilt mechanism 106 is capable of tilting the scanner 20 around its axis based on the control of the control device 24. The tilt mechanism 106 switches the orientation of the scanner 20 by tilting it. The scanner drive device 22 moves the scanner 20 horizontally by moving the support column 103 with the horizontal movement device 102.

[0035] The scanner drive unit 22 moves the scanner 20 vertically by moving the slider 105 along the rail 104. The scanner drive unit 22 tilts the scanner 20 around the axis of rotation by the tilt mechanism 106. By moving the scanner 20, the scanner drive unit 22 moves the scanner 20 and the subject P relative to each other.

[0036] The control device 24 includes, for example, a processing circuit having a processor such as a CPU (Central Processing Unit), and a drive mechanism including a motor and an actuator. The processing circuit realizes these functions, for example, by having a hardware processor execute a program stored in a memory device (storage circuit).

[0037] Hardware processors refer to circuits such as CPUs (Central Processing Units), GPUs (Graphics Processing Units), Application Specific Integrated Circuits (ASICs), programmable logic devices (e.g., Simple Programmable Logic Devices (SPLDs) or Complex Programmable Logic Devices (CPLDs)), and Field Programmable Gate Arrays (FPGAs).

[0038] Instead of storing the program in a memory device, the program can be directly embedded within the hardware processor's circuitry. In this case, the hardware processor performs its functions by reading and executing the program embedded within the circuitry.

[0039] A hardware processor is not limited to being a single circuit; it may be composed of multiple independent circuits combined to perform various functions. The memory device may be a non-temporary (hardware) storage medium. Furthermore, multiple components may be integrated into a single hardware processor to perform various functions.

[0040] The control device 24, for example, rotates the rotating frame 17, moves the scanner 20 using the scanner drive device 22, and moves the top plate 33 of the bed device 30. The top plate 33 serves as the bed when the subject P is placed in a supine position.

[0041] For example, when tilting the scanner 20, the control device 24 controls the tilt mechanism 106 of the scanner drive unit 22 and rotates the rotation frame 17 around an axis parallel to the Z-axis direction based on the tilt angle input to the input interface 43.

[0042] The control device 24 determines the rotation angle of the rotating frame 17 based on the output of a sensor (not shown), etc. The control device 24 also provides the rotation angle of the rotating frame 17 to the processing circuit 50 as needed. The control device 24 may be installed on the mounting device 10 or on the console device 40.

[0043] The patient bed device 30 is a device that places and moves the subject P to be scanned and introduces it into the rotating frame 17 of the stand device 10. The patient bed device 30 comprises, for example, a base 31, a patient bed drive device 32, a top plate 33, and a support frame 34.

[0044] The base 31 includes a housing that supports the support frame 34 so that it can move vertically (in the Y-axis direction).

[0045] The bed drive device 32 includes a motor and actuators. The bed drive device 32 moves the tabletop 33 on which the subject P is placed along the support frame 34 in the longitudinal direction (Z-axis direction) of the tabletop 33.

[0046] The top plate 33 is a plate-shaped member on which the subject P is placed. The bed drive device 32 retracts the top plate 33 and inserts it into the central opening 19 of the scanner 20. The bed drive device 32 then advances the top plate 33 and withdraws it from the scanner 20.

[0047] The bed drive device 32 may move not only the top plate 33 but also the support frame 34 in the longitudinal direction of the top plate 33. Conversely, the support device 10 may be movable in the Z-axis direction, and the movement of the support device 10 may be controlled so that the rotating frame 17 is positioned around the subject P. Alternatively, both the support device 10 and the top plate 33 may be movable.

[0048] Figure 3 is a perspective view showing an example of an X-ray CT scanner 1 examining a subject P in a supine position. Figure 4 is a perspective view showing an example of an X-ray CT scanner 1 examining a subject P in an upright position.

[0049] As shown in Figure 3, the subject P, placed on the examination table 30, is examined in a supine position. The X-ray CT scanner 1 can also examine a subject P in an upright position, as shown in Figure 4. When examining a subject P in an upright position, for example, a support device is used to support the upright subject P. The examination table 30 may be equipped with a displacement structure that displaces the subject P between a supine position and an upright position.

[0050] Furthermore, as shown in Figure 3, a display panel 42a and operation buttons 43a are provided on the front of the support column 103. This allows, for example, the operator to adjust the position of the scanner 20 when examining a supine subject P in an examination room equipped with the X-ray CT scanner 1 by checking the display content of the display panel 42a and inputting commands using the operation buttons 43a.

[0051] Furthermore, as shown in Figure 4, a display panel 42b and operation buttons 43b are provided on the rear surface of the support column 103. This allows, for example, the operator to adjust the position of the scanner 20 when examining a standing subject P in an examination room equipped with the X-ray CT scanner 1 by checking the display content of the display panel 42b and inputting commands using the operation buttons 43b.

[0052] In addition, either the display panel 42a and operation button 43a, or the display panel 42b and operation button 43b, may be provided by themselves.

[0053] Furthermore, the X-ray CT apparatus 1 according to this embodiment can also examine a subject P sitting in a chair or wheelchair, i.e., a seated subject P, using the same method as when examining a standing subject P as shown in Figure 4. The examination of a seated subject P will be described later.

[0054] The stand device 10 and the patient device 30 switch the relative direction of movement between the X-ray detector 15 provided on the scanner 20 and the subject P supported on the tabletop 33, for example, by a horizontal movement device 102, a slider 105, and a patient drive device 32.

[0055] For example, when scanning the entire body of a subject P positioned parallel to the Z direction, the stand device 10 and the bed device 30 move the scanner 20 in the Z direction together with the support column 103 by the horizontal movement device 102.

[0056] Furthermore, for example, when scanning a subject P along the OM line (Orbitomeatal baseline) which is inclined from the Z direction around the X axis, the rigging device 10 and the patient table device 30 move the scanner 20 in the Z and Y directions using the horizontal movement device 102 and the slider 105.

[0057] The console device 40 includes, for example, a memory 41, a display 42, an input interface 43, and a processing circuit 50. In this embodiment, the console device 40 is described as separate from the mounting device 10, but the mounting device 10 may include some or all of the components of the console device 40.

[0058] Memory 41 can be implemented using, for example, semiconductor memory elements such as RAM (Random Access Memory) or flash memory, a hard disk, or an optical disc. Memory 41 stores, for example, detection data, projection data, reconstructed image data, CT image data, etc.

[0059] The above data may be stored in an external memory that the X-ray CT apparatus 1 can communicate with, rather than in memory 41 (or in addition to memory 41). The external memory is controlled by a cloud server, for example, by accepting read and write requests from the cloud server that manages the external memory.

[0060] The display 42 displays various types of information. For example, the display 42 is an output interface that displays medical images (CT images) generated by the processing circuit, as well as GUI (Graphical User Interface) images that accept various operations from operators such as doctors and technicians.

[0061] The display 42 may be, for example, a liquid crystal display, a CRT (Cathode Ray Tube), or an organic EL (Electroluminescence) display. The display 42 may be mounted on the stand device 10. The display 42 may be a desktop type, or it may be a display device (for example, a tablet terminal) that can communicate wirelessly with the main body of the console device 40.

[0062] In this embodiment, display panel 42a and display panel 42b are included in the display 42.

[0063] The input interface 43 receives various input operations from the operator and outputs an electrical signal indicating the content of the received input operation to the processing circuit 50.

[0064] For example, the input interface 43 accepts input operations such as collection conditions when collecting detection data or projection data, reconstruction conditions when reconstructing CT images, and image processing conditions when generating post-processed images from CT images. In this embodiment, the collection conditions include the posture of the subject P at the time of imaging (lying down, standing, sitting, etc.).

[0065] The input interface 43 can be implemented by, for example, a mouse, keyboard, touch panel, drag ball, switch, button, joystick, camera, infrared sensor, microphone, etc. The input interface 43 may also be implemented by a display device (e.g., a tablet terminal) that can communicate wirelessly with the main body of the console device 40.

[0066] In this embodiment, the operation buttons 43b and 43b are included in the input interface 43.

[0067] In this specification, the term "input interface" is not limited to those equipped with physical operating components such as a mouse or keyboard. For example, an electrical signal processing circuit that receives an electrical signal corresponding to an input operation from an external input device located separately from the device and outputs this electrical signal to a control circuit is also included as an example of an input interface.

[0068] The processing circuit 50 controls the overall operation of the X-ray CT apparatus 1. The processing circuit 50 includes, for example, a control function 51, a preprocessing function 52, a reconstruction processing function 53, an image processing function 54, and a setting function 55. The processing circuit 50 realizes these functions, for example, by having a hardware processor execute a program stored in a memory device (storage circuit).

[0069] Hardware processors refer to circuits such as CPUs, GPUs, application-specific integrated circuits, programmable logic devices or composite programmable logic devices, and field-programmable gate arrays. Instead of storing programs in memory, the program may be directly embedded within the hardware processor's circuitry.

[0070] A hardware processor is not limited to being a single circuit; it may be composed of multiple independent circuits combined to perform various functions. The memory device may be a non-temporary (hardware) storage medium. Furthermore, multiple components may be integrated into a single hardware processor to perform various functions.

[0071] Each component of the console device 40 or the processing circuit 50 may be distributed and implemented by multiple hardware components. The processing circuit 50 may not be implemented by the console device 40, but by a processing unit that can communicate with the console device 40.

[0072] The processing unit is, for example, a workstation connected to a single X-ray CT scanner, or a device (e.g., a cloud server) connected to multiple X-ray CT scanners that performs processing equivalent to the processing circuit 50 described below in a single operation.

[0073] The control function 51 controls various functions of the processing circuit 50 based on input operations received by the input interface 43. For example, the control function 51 controls the X-ray high-voltage device 14, DAS 16, control device 24, and the bed drive device 32 of the bed device 30 to perform data collection processing of detection data in the support frame device 10.

[0074] Furthermore, for example, the control function 51 accepts input of subject information, including the subject P's posture during imaging. Specifically, the control function 51 accepts input of posture information (lying down / standing / sitting, etc.) and body size information (gender, height, weight, etc.) related to the subject P's posture during imaging. Posture information and body size information are examples of subject information. In this case, the control function 51 can also be said to be acquiring subject information, and therefore can be said to be an example of an acquisition unit.

[0075] The control function 51 may also acquire the posture information and body size information of the subject P by receiving an examination order from an external device. For example, the control function 51 may receive an examination order including the posture information and body size information of the subject P from a Radiology Information System (RIS) server or the like.

[0076] The preprocessing function 52 performs preprocessing on the detection data output by DAS16, such as logarithmic transformation, offset correction, inter-channel sensitivity correction, and beam hardening correction, to generate projection data, and stores the generated projection data in memory 41.

[0077] The reconstruction processing function 53 performs reconstruction processing on the projection data set by the preprocessing function 52, such as a filtered back projection method or an iterative reconstruction method, to generate CT image data, and stores the generated CT image data in the memory 41.

[0078] The image processing function 54 converts CT image data into three-dimensional image data or cross-sectional image data of an arbitrary cross-section using a known method, based on the input operation received by the input interface 43. The conversion to three-dimensional image data may be performed by the preprocessing function 52.

[0079] The setting function 55 allows you to set the descent speed, which represents the speed at which the scanner 20 moves downward in the vertical direction (negative Y-axis direction) when the shooting posture is seated.

[0080] The following explains, using Figure 5, the reason for setting the scanner 20's descent speed when performing seated imaging. Figure 5 shows an example of imaging a subject P sitting in a wheelchair.

[0081] As shown in Figure 5, when photographing a subject P seated in a wheelchair WC, it is preferable that the area of ​​subject P being photographed is located on the center line CL, which represents the center in the X-axis direction of the central opening 19 of the scanner 20. In this case, if the scanner 20 descends below line WL, there is a possibility of interference between the scanner 20 and the wheelchair WC. Also, if the scanner 20 descends below line KL, there is a possibility of interference between the scanner 20 and the knees of subject P.

[0082] Thus, if the scanner 20 moves at high speed in the interference region IC where the wheelchair WC or subject P's knees may come into contact with the scanner 20, it may not be possible to immediately stop the scanner 20's descent even if the wheelchair WC or subject P's knees are about to come into contact with the scanner 20. Also, even when contact between the scanner 20 and the wheelchair WC or subject P's knees can be avoided, if the scanner 20 moves at high speed in an area where the wheelchair WC or subject P's knees may come into contact with the scanner 20, some subjects P may become anxious that the scanner 20 might come into contact with the wheelchair WC or themselves.

[0083] Therefore, in this embodiment, the setting function 55 performs a process to set the descent speed of the scanner 20 according to the vertical position of the scanner 20, in order to prevent the scanner 20 from moving at high speed in areas where the wheelchair WC or the subject P's knees may come into contact with the scanner 20.

[0084] For example, if the posture information received by the control function 51 is for seated imaging, the setting function 55 sets the first scan stroke, the second scan stroke, and the third scan stroke according to the body size information of the subject P. The first scan stroke and the second scan stroke are examples of the first interval. The third scan stroke is an example of the second interval.

[0085] The first scan stroke is, for example, the head imaging area, and represents the range in which the scanner 20 may be located in the vertical direction when imaging the head of subject P. The first scan stroke is an area in which there is considered to be no risk of the scanner 20 getting caught between the knees of the seated subject P and the floor (hereinafter also referred to as interference risk).

[0086] Furthermore, the second scan stroke is, for example, the chest imaging area, and represents the range in which the scanner 20 may be located in the vertical direction when imaging the chest of subject P. The second scan stroke is an area where interference risk may be considered in some cases.

[0087] Furthermore, the third scan stroke is, for example, the lung field imaging area, and represents the range in which the scanner 20 may be located in the vertical direction when imaging the lung field of subject P. The third scan stroke is an area where the risk of interference is considered high.

[0088] Specifically, the setting function 55 sets the section in the vertical direction where the scanner 20 is presumed to be present when photographing the head of subject P, based on the height of subject P included in the subject P's physical size information, as the first scan stroke.

[0089] Similarly, the setting function 55 sets the section in the vertical direction in which the scanner 20 is presumed to be located when imaging the chest of subject P as the second scan stroke. Furthermore, the setting function 55 similarly sets the section in the vertical direction in which the scanner 20 is presumed to be located when imaging the lung field of subject P as the third scan stroke.

[0090] The setting function 55 may also adjust the position of the boundary line between scan strokes according to the gender and weight of the subject P.

[0091] Furthermore, although three scan strokes are set in this embodiment, the number of scan strokes is not limited to three. For example, the setting function 55 may set two scan strokes (for example, dividing the area into sections with interference risk and sections without interference risk), or it may set four or more scan strokes (for example, dividing the area with interference risk into low-probability, medium-probability, and high-probability sections).

[0092] Here, Figure 6 illustrates an example of the process for setting the descent speed. Figure 6 shows an example of the process for setting the descent speed when photographing a subject P sitting in a chair EC. Below, we will explain the case where the setting function 55 sets the first scan stroke SS1, the second scan stroke SS2, and the third scan stroke SS3 as shown in Figure 6.

[0093] In this case, the setting function 55 sets the descent speed of the scanner 20 for the first scan stroke SS1 to high speed, the descent speed of the scanner 20 for the second scan stroke SS2 to medium speed, and the descent speed of the scanner 20 for the third scan stroke SS3 to low speed. Here, high speed is an example of the first speed. Medium speed is an example of the third speed. Low speed is an example of the second speed.

[0094] In this embodiment, high speed represents descending the scanner 20 without speed restrictions (with a preset maximum speed as the upper limit). Medium speed represents descending the scanner 20 with a preset intermediate speed as the upper limit. Low speed represents descending the scanner 20 with a preset low speed as the upper limit. It is assumed that maximum speed > intermediate speed > low speed.

[0095] In Figure 6, the setting function 55 divides the scan stroke into three sections, but it is also possible to set the scan stroke into two sections: one with interference risk and one without. In this case, the setting function 55 may set the descent speed of the scanner 20 to high in the section without interference risk and to low in the section with interference risk.

[0096] Furthermore, although Figure 6 illustrates the case of photographing a subject P seated in a chair EC, the setting function 55 may also be configured to set the scan stroke considering the case of photographing a subject P seated in a wheelchair WC. In this case, the control function 51 may accept input from the operator to select whether to photograph using the chair EC or the wheelchair WC as part of the information included in the shooting conditions.

[0097] For example, when scanning using a wheelchair WC, the setting function 55 may be adjusted to slightly widen the third scan stroke SS3 upwards compared to when scanning using a chair EC. This is because wheelchairs generally have components such as armrests that may interfere with the scanner 20 at a position higher than the knees of the person sitting in them.

[0098] Furthermore, if the setting function 55 is used to set the descent speed of the scanner 20, the control function 51 controls the control device 24 to control the descent speed of the scanner 20 based on the setting and the vertical position of the scanner 20. In this case, the control function 51 is an example of an operation control unit.

[0099] For example, as shown in Figure 6, when a can stroke is set, the control function 51 controls the scanner 20 to descend at high speed when the scanner 20 is located within the can stroke SS1 in the vertical direction. The control function 51 also controls the scanner 20 to descend at a medium speed when the scanner 20 is located within the can stroke SS2 in the vertical direction. Furthermore, the control function 51 controls the scanner 20 to descend at a low speed when the scanner 20 is located within the can stroke SS3 in the vertical direction.

[0100] Furthermore, if the control function 51 is to lower the scanner 20 beyond the boundary line between scan strokes, it may, for safety reasons, temporarily suspend the lowering of the scanner 20 when the lower end of the scanner 20 in the vertical direction reaches the boundary line.

[0101] Furthermore, when moving (raising) the scanner 20 in the vertical direction upward (positive Y-axis direction), the control function 51 may move the scanner 20 at high speed. This is because there is no risk of interference when raising the scanner 20.

[0102] Furthermore, the control function 51 displays the movement speed of the scanner 20 on the display unit. For example, the control function 51 controls the display panel 42a to display the current movement speed of the scanner 20 and the approximate vertical position of the scanner 20. In this case, the control function 51 is an example of a display control unit.

[0103] The control function 51 may also display the current operating speed of the scanner 20 and its approximate vertical position on the display panel 42a or on another display device (display unit) such as a display installed in an operation room different from the examination room.

[0104] Here, Figure 7 shows an example of a display screen 421 for the operating speed of the scanner 20. The display screen 421 has a screen configuration consisting of an attitude display field PD, a speed display field SD, and a scanner position display field TP.

[0105] The posture display area PD is a display area that shows the posture information of the subject P as an image. In Figure 7, the posture display area PD indicates that the subject P was sitting when photographed.

[0106] The speed display field SD shows the current movement speed of the scanner 20. In Figure 7, it shows that the current movement speed of the scanner 20 is medium.

[0107] In this embodiment, the movement speed of the scanner 20 is expressed as high, medium, and low, but the display method of the scanner 20's movement speed is not limited to these. For example, the control function 51 may display the scanner 20's movement speed as a numerical value (e.g., kilometers per hour, meters per minute, meters per second, etc.).

[0108] The scanner position indicator TP represents the approximate current position of the scanner 20 in the vertical direction. In this embodiment, the scanner position indicator TP indicates whether the scanner 20 is located in a position corresponding to the first scan stroke SS1, the second scan stroke SS2, or the third scan stroke SS3. Figure 7 shows that the approximate current position of the scanner 20 in the vertical direction corresponds to the position of the second scan stroke SS2.

[0109] Next, the processes performed by the X-ray CT apparatus 1 according to this embodiment will be described. Figure 8 is a flowchart showing an example of the processes performed by the X-ray CT apparatus 1 according to this embodiment.

[0110] First, the control function 51 receives the shooting conditions (step S101). For example, the control function 51 receives input of shooting conditions, including the posture information and body size information of the subject P, from the operator via the input interface 43.

[0111] Next, the setting function 55 determines whether to perform seated imaging of subject P (step S102). For example, if the posture information of subject P included in the imaging conditions received in step S101 is seated, the setting function 55 determines to perform seated imaging of subject P. If seated imaging of subject P is not performed (step S102: No), the process proceeds to step S104, which will be described later.

[0112] When performing a seated imaging of subject P (Step S102: Yes), the setting function 55 sets the scan stroke (Step S103).

[0113] For example, the setting function 55 sets the first scan stroke SS1 to the third scan stroke SS3 according to the physical size information of the subject P (height of subject P) included in the imaging conditions accepted in step S101.

[0114] Specifically, the setting function 55 sets the section in the vertical direction where the scanner 20 is presumed to be present when imaging the head of subject P as the first scan stroke SS1. The setting function 55 also sets the section in the vertical direction where the scanner 20 is presumed to be present when imaging the chest of subject P as the second scan stroke SS2. Furthermore, the setting function 55 sets the section in the vertical direction where the scanner 20 is presumed to be present when imaging the lung fields of subject P as the third scan stroke SS3.

[0115] Next, the control function 51 controls the movement of the scanner 20 to photograph the subject P (step S104). For example, in the case of supine or standing imaging, the control function 51 controls the control device 24 (and the bed drive device 32 of the bed device 30 in the case of supine imaging) to move the scanner 20 at a predetermined speed to photograph the subject P.

[0116] Furthermore, for example, in the case of seated imaging, the control function 51 controls the control device 24 to move the scanner 20 at a speed based on the scan stroke set in step S103 to take an image of the subject P. Specifically, the control function 51 lowers the scanner 20 at high speed for the first scan stroke SS1, at medium speed for the second scan stroke SS2, and at low speed for the third scan stroke SS3 to take an image of the subject P.

[0117] Next, the control function 51 determines whether an instruction has been given to end the imaging of the subject P (step S105).

[0118] For example, the control function 51, via the input interface 43, determines whether the operator has given an instruction to end the imaging process for subject P. If there is no instruction to end the imaging process for subject P (step S105: No), the process returns to step S104. On the other hand, if there is an instruction to end the imaging process for subject P (step S105: Yes), this process is terminated.

[0119] In the above explanation, the movement of the scanner 20 in step S104 was described as movement that occurs while the subject P is being photographed. However, the movement of the scanner 20 in step S104 may also be movement of the scanner 20 when adjusting the height position of the scanner 20 in accordance with the operator's actions before photographing the subject P.

[0120] Furthermore, depending on the scan stroke setting set in step S103, an upward speed representing the speed at which the scanner 20 moves upward in the vertical direction (positive Y-axis direction) may be set.

[0121] For example, when moving the scanner 20 from its position at the time the subject P has been photographed to an initial position set to the highest position in the scanner 20's range of motion, the scanner drive unit 22 may be controlled so that the upward speed increases as the distance between the scanner 20 and the initial position decreases, according to the scan stroke setting set in step S103.

[0122] As described above, the X-ray CT apparatus 1 according to this embodiment receives imaging conditions including the posture information and body size information of the subject P. When the imaging posture is seated, it sets a first scan stroke SS1 with a high descent speed of the scanner 20, a second scan stroke SS2 with a medium speed, and a third scan stroke SS3 with a low speed, and controls the descent speed of the scanner 20 based on the set first scan strokes SS1 to third scan strokes SS3 and the vertical position of the scanner 20.

[0123] As a result, in the third scan stroke SS3, where the risk of interference is high, the scanner 20 descends at a low speed. Therefore, for example, if the operator sees the scanner 20 about to come into contact with the subject P's knee, there is a higher probability that the operator can stop the scanner 20 before contact occurs. In addition, it is possible to suppress the anxiety that the subject P may experience due to the scanner 20 moving at high speed in areas with a high risk of interference. In other words, according to the X-ray CT apparatus 1 of this embodiment, a stroke suitable for the subject P can be secured without causing anxiety to the subject P during seated imaging.

[0124] The above-described embodiment can also be modified and implemented as appropriate by changing some of the configurations or functions of the X-ray CT apparatus 1. Therefore, the following describes modified examples of the above-described embodiment as other embodiments. In the following, we will mainly describe the differences from the above-described embodiment, and will omit detailed explanations of points that are common with what has already been described. Furthermore, the modified examples described below may be implemented individually or in combination as appropriate.

[0125] (Variation 1) In the above-described embodiment, a configuration was explained in which the first scan stroke SS1 to the third scan stroke SS3 are set according to the physique information of the subject P. In this modified example, a configuration is described in which the first scan stroke SS1 to the third scan stroke SS3 are set based on pre-stored information.

[0126] In this modified example, memory 41 or other storage device stores section information representing the first scan stroke SS1 to the third scan stroke SS3. The section information may be configured to be changeable by the operator.

[0127] For example, if X-ray CT scanner 1 is used only in pediatrics, and the interval information is set to match the average adult physique, the difference between the assumed physique of subject P and the actual physique of subject P will be large. However, by configuring the interval information to be changeable, it is possible to set the interval information to match the average physique of a child, thereby reducing the difference between the assumed physique of subject P and the actual physique of subject P.

[0128] In this modified example, the setting function 55, when it determines from the shooting conditions received by the control function 51 that a seated position of subject P should be photographed, refers to the interval information stored in the memory 41 and sets the first scan stroke SS1 to the third scan stroke SS3 based on that interval information. Also, similar to the embodiment described above, the setting function 55 sets the descent speed of the scanner 20 based on the set first scan stroke SS1 to the third scan stroke SS3.

[0129] In addition to the descent speed of the scanner 20, the setting function 55 may also be used to set the operation switches for operating the scanner 20. The operation switches are included in the input interface 43. The operation switches may also be included in the operation buttons 43a and 43b.

[0130] For example, the setting function 55 may be configured not to accept input from the operation switch if the scanner 20 is within the third scan stroke SS3. Alternatively, in this case, the setting function 55 may be configured to accept input from the operation switch only if another switch (for example, an override switch) is pressed simultaneously with the operation switch.

[0131] As a result, in areas with a high risk of interference, the scanner 20 will not move even if the operator only presses the operation switch. Therefore, it becomes easier for the operator to recognize when the risk of interference is high, and they can operate the scanner 20 more carefully in areas with a high risk of interference.

[0132] According to this modified example, the process of setting the scan stroke based on the physical size information of the subject P becomes unnecessary, thus reducing the processing load on the processing circuit 50.

[0133] (Modification 2) In the above-described embodiment, a configuration was explained in which the first scan stroke SS1 to the third scan stroke SS3 are set according to the physique information of the subject P. In this modified example, a configuration is described in which the first scan stroke SS1 to the third scan stroke SS3 are set based on an image of the subject P captured by a camera.

[0134] In this modified example, the X-ray CT scanner 1 is equipped with at least one camera. The camera is positioned to capture images of the subject P before the scanner 20 is moved downward in the vertical direction.

[0135] For example, in this modified example, if the setting function 55 determines from the shooting conditions received by the control function 51 that a seated position of subject P should be photographed, it acquires a subject image representing the state of subject P before moving the scanner 20 captured by the camera downwards in the vertical direction. Based on this subject image, the setting function 55 sets the scan stroke.

[0136] Specifically, the setting function 55 uses known image analysis techniques to estimate the positions of the subject P's head, chest, and lungs from the acquired subject images. Based on the estimated positions of the subject P's head, chest, and lungs, the setting function 55 sets the first scan stroke SS1 to the third scan stroke SS3.

[0137] The setting function 55 may also detect the position of any components that may interfere with the scanner 20, such as the armrests of a wheelchair, and set the first scan stroke SS1 to the third scan stroke SS3 taking the position of such components into consideration.

[0138] According to this modified version, a unique scan stroke can be set for each subject P based on the image of the subject P that has actually been captured, making it possible to secure a stroke that is more suitable for the subject P.

[0139] (Variation 3) In the embodiments described above, a configuration was described in which the descent speed of the scanner 20 is set based on a set scan stroke. In this modification, a configuration is described in which the restriction on the descent speed is relaxed in the vertical direction, based on the lowest position the scanner 20 has reached from the start of the examination of the subject P.

[0140] For example, the setting function 55 in this modified example stores position information in the memory 41 that represents the lowest position the scanner 20 is in the vertical direction. The setting function 55 also starts this process when the examination of subject P begins and continues until the examination of subject P is completed.

[0141] Furthermore, the setting function 55 sets the descent speed of the scanner 20 to a high speed, regardless of the scan stroke, if the scanner 20 is located above the position corresponding to the position information in the vertical direction. This is because it can be estimated that the scanner 20 will not pinch the knees of the seated subject P between itself and the floor until it reaches its lowest position in the vertical direction.

[0142] This allows the operator to lower the scanner 20 over the widest possible range without speed restrictions, for example, by informing the subject P in advance that the scanner 20 will not move below its lowest position in the vertical direction, without causing anxiety to the subject P.

[0143] In addition, the setting function 55 may store a position specified by the operator as position information in the memory 41, instead of the lowest position of the scanner 20 in the vertical direction from the start of the inspection.

[0144] According to this modified version, for example, the scanner 20 can be lowered at high speed within a range that does not cause anxiety to the subject P.

[0145] (Modification 4) In the embodiment described above, a configuration was described in which the control function 51 switches the descent speed of the scanner 20 to lower the scanner 20 for each set scan stroke. In this modified example, a configuration is described in which the descent speed of the scanner 20 decreases as the distance between the scanner 20 and the subject P decreases.

[0146] In this modified example, the setting function 55 sets the descent speed of the scanner 20 such that the descent speed of the scanner 20 decreases as the distance between the scanner 20 and the subject P decreases.

[0147] Furthermore, the setting function 55 may set the descent speed of the scanner 20 to high while the scanner 20 is in the first scan stroke SS1. In this case, the setting function 55 may set the upper limit of the descent speed to low once the scanner 20 enters the second scan stroke SS2, and set the descent speed of the scanner 20 to decrease as the distance between the scanner 20 and the subject P decreases.

[0148] Furthermore, the setting function 55 may be used to set the descent speed of the scanner 20 such that the upper limit of the descent speed is the maximum speed while the scanner 20 is in the first scan stroke SS1, and the descent speed of the scanner 20 approaches an intermediate speed as the scanner 20 approaches the second scan stroke SS2.

[0149] In the above case, the setting function 55 may also set the descent speed of the scanner 20 such that the upper limit of the descent speed is an intermediate speed while the scanner 20 is in the second scan stroke SS2, and the descent speed of the scanner 20 approaches a low speed as the scanner 20 approaches the third scan stroke SS3.

[0150] In the above case, the setting function 55 may also set the descent speed of the scanner 20 to a low upper limit once the scanner 20 enters the third scan stroke SS3, and to decrease the descent speed of the scanner 20 as the distance between the scanner 20 and the subject P decreases.

[0151] According to this modified version, it is possible to reduce the discomfort that may occur in the subject P due to a sudden change in the descent speed of the scanner 20.

[0152] According to at least one embodiment described above, the risk of contact between the scanner and the subject during seated imaging can be reduced.

[0153] While several embodiments have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of Symbols]

[0154] 1 X-ray CT device 10. Mounting device 11 X-ray tube 12 Wedge 13 Collimator 15 X-ray detector 16 DAS 17 rotation frames 18 Cover 19 Central opening 20 Scanners 22 Scanner drive unit 24 Control device 30 Bed equipment 31 base 32 Bed drive mechanism 33 Top plate 34 Support Frame 40 Console device 42 displays 43 Input Interfaces 50 Processing Circuits 51 Control Functions 52 Pre-processing function 53 Reconstruction Processing Function 54 Image processing functions 55 Settings Function 101 Bass 102 Horizontal movement device 103 Support column 104 rails 105 Slider 106 Tilt mechanism

Claims

1. A scanner unit with an imaging system, A support unit that supports the scanner unit and moves the scanner unit in the vertical direction, An acquisition unit that acquires subject information, including the subject's posture during imaging, When the aforementioned shooting posture is seated, a setting unit sets a first section in which the descent speed, which represents the speed at which the scanner unit moves downward in the vertical direction, is less than or equal to a first speed, and a second section in which the descent speed is less than or equal to a second speed. An operation control unit controls the descent speed based on the set first section and second section and the vertical position of the scanner unit, Equipped with, The first speed is greater than the second speed. The first section is the section located vertically above the second section. X-ray CT device.

2. The acquisition unit acquires the subject information, including body size information representing the subject's physique. The setting unit sets the first section and the second section based on the body size information. The X-ray CT apparatus according to claim 1.

3. The acquisition unit acquires the body size information based on an image of the subject taken by a camera of the subject in a seated position. The X-ray CT apparatus according to claim 2.

4. The acquisition unit acquires the subject information by receiving an examination order including the body size information from an external device. The X-ray CT apparatus according to claim 2.

5. The setting unit sets a third section in which the descent speed is less than or equal to the third speed when the shooting posture is seated. The third speed is greater than the second speed and less than the first speed. The third section is located vertically above the second section and below the first section. The X-ray CT apparatus according to claim 1.

6. The operation control unit, when the scanner unit is located in the first section, lowers the scanner unit with the upper limit of the descent speed set to the first speed, and when the scanner unit moves from the first section to the second section in the vertical direction, switches the upper limit of the descent speed from the first speed to the second speed and lowers the scanner unit. The X-ray CT apparatus according to claim 1.

7. The operation control unit, when the scanner unit is located in the first section, lowers the scanner unit so that the upper limit of the descent speed is set to the first speed, and the descent speed approaches the second speed as the scanner unit approaches the second section; when the scanner unit is located in the second section, lowers the scanner unit so that the upper limit of the descent speed is set to the second speed, and the descent speed decreases as the scanner unit moves downward in the vertical direction. The X-ray CT apparatus according to claim 1.

8. The system further includes a display control unit that displays information regarding the descent speed on the display unit. The X-ray CT apparatus according to any one of claims 1 to 7.

9. The display control unit causes the display unit to display information representing the shooting posture and the vertical position of the scanner unit together with information regarding the descent speed. The X-ray CT apparatus according to claim 8.

10. A control method for an X-ray CT apparatus comprising a scanner unit having an imaging system and a support unit that supports the scanner unit and moves the scanner unit in the vertical direction, We obtain subject information, including the subject's posture during imaging. When the aforementioned shooting posture is seated shooting, a first section is set in which the descent speed, which represents the speed at which the scanner unit is moved downward in the vertical direction, is a first speed, and a second section is set in which the descent speed is a second speed. Based on the set first and second sections and the vertical position of the scanner unit, the descent speed is controlled. The first speed is greater than the second speed. The first section is the section located vertically above the second section. A control method using an X-ray CT scanner.

11. A program to be executed by the computer of an X-ray CT apparatus comprising a scanner unit having an imaging system and a support unit that supports the scanner unit and moves the scanner unit in the vertical direction, We obtain subject information, including the subject's posture during imaging. When the aforementioned shooting posture is seated shooting, a first section is set in which the descent speed, which represents the speed at which the scanner unit is moved downward in the vertical direction, is a first speed, and a second section is set in which the descent speed is a second speed. Based on the set first and second sections and the vertical position of the scanner unit, the descent speed is controlled. The first speed is greater than the second speed. The first section is the section located vertically above the second section. program.

Images