X-ray CT apparatus

Abstract

To provide an X-ray CT apparatus capable of improving workability of maintenance.SOLUTION: An X-ray CT apparatus includes a plurality of components including an X-ray source and an X-ray detector, a rotation frame that is loaded with the plurality of components and rotates, and a support frame that supports the rotation frame rotatably. The support frame includes one or more lock mechanisms having a stationary shaft and a support member for supporting the stationary shaft movably. The support frame includes one or more lock fixing parts that can engage with the stationary shaft. The lock mechanism switches the states between a lock state for regulating the rotation of the rotation frame, and an unlock state for enabling the rotation frame to rotate.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to an X-ray CT apparatus, and more particularly to an X-ray CT apparatus in which maintenance work is easy to perform. [Background technology]

[0002] An X-ray CT scanner comprises a rotating frame on which an X-ray tube and an X-ray detection unit, etc. are mounted, and a support frame that rotatably supports the rotating frame. The rotating frame is rotated by a rotating belt driven by a motor. The rotating frame and the rotating belt, etc. are housed in a housing (gantry cover). The rotating frame is stopped during operation by stopping the rotating belt with a brake device.

[0003] When performing maintenance on the X-ray CT device, the gantry cover is removed. The rotating frame is locked and its rotation is restricted. In the locked state, parts mounted on the X-ray CT device are repaired or replaced. Patent Document 1 discloses a mechanism for locking the rotating frame. Patent Document 1 discloses that the rotating frame is locked by engaging the tip of a locking mechanism provided on the support frame with a fixing hole or fixing protrusion provided on the support frame. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-147652 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, when locking the rotating frame, the worker needs to engage the locking mechanism, which is located in a recessed position, with the fixing hole, etc. This causes a decrease in the efficiency of maintenance work.

[0006] The present invention has been made to solve the above-mentioned problems, and has an object to provide an X-ray CT apparatus capable of improving the ease of maintenance work. [Means for solving the problem]

[0007] The first embodiment of the X-ray CT device comprises a plurality of components including an X-ray source and an X-ray detector, a rotating frame that rotates while mounting the plurality of components, and a support frame that rotatably supports the rotating frame, the support frame having one or more locking mechanisms comprising a fixed shaft and a support member that movably supports the fixed shaft, the support frame having one or more lock fixing portions that can engage with the fixed shaft, and the locking mechanism switches between a locked state that restricts rotation of the rotating frame and an unlocked state that allows rotation of the rotating frame.

[0008] In the X-ray CT apparatus of the second aspect, in a locked state in which the fixed shaft of the lock mechanism and the lock fixing portion are engaged with each other, any one of the plurality of parts is positioned below the rotation shaft of the rotating frame.

[0009] In the X-ray CT apparatus of the third aspect, any one of the plurality of components is an X-ray source.

[0010] In the X-ray CT apparatus of the fourth aspect, the one or more lock fixing parts include a plurality of lock fixing parts.

[0011] In the X-ray CT apparatus of the fifth aspect, any one of the plurality of components is positioned at a predetermined position according to a combination of lock states in which one of the plurality of lock fixing parts is engaged with the fixed shaft of the lock mechanism.

[0012] In the X-ray CT apparatus of the sixth aspect, the one or more locking mechanisms include a plurality of locking mechanisms.

[0013] In the X-ray CT apparatus of the seventh aspect, any one of the plurality of components is positioned at a predetermined position according to a combination of lock states in which the fixed shaft of one of the plurality of lock mechanisms is engaged with the lock fixing portion.

[0014] In the X-ray CT apparatus of the eighth aspect, the fixed axis is disposed offset with respect to the support member.

[0015] In the X-ray CT apparatus of the ninth aspect, the locking mechanism includes an index that indicates whether the support member is in a position for locking or unlocking the rotating frame.

[0016] In the X-ray CT apparatus of the tenth aspect, the locking mechanism includes an elastic member that biases the support member to a position where the rotating frame is in an unlocked state.

[0017] In the X-ray CT apparatus of an eleventh aspect, a motor for rotating the rotating frame is provided, and a processor for turning off the power supply of the motor when the rotating frame is in a locked state is provided.

[0018] In the X-ray CT apparatus of the twelfth aspect, in a state in which the fixed shaft is engaged with the lock fixing portion, the fixed shaft can maintain the rotating frame in a locked state against the maximum output of the motor. Effect of the Invention

[0019] According to the present invention, the efficiency of maintenance work can be improved. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a perspective view illustrating the overall appearance of an X-ray CT apparatus. [Diagram 2] 1 is a block diagram showing an overall structure of an X-ray CT apparatus according to an embodiment. [Diagram 3] FIG. [Figure 4] 2 is a front view of a rotating disk unit of the X-ray CT apparatus according to the embodiment with a gantry cover removed. FIG. [Diagram 5] 5 is a front view of the rotating disk unit in FIG. 4 with a rotating frame removed. [Figure 6] 13A and 13B are diagrams illustrating a rotating frame in a locked state. [Figure 7] FIG. 13 is a diagram for explaining a lock mechanism in a locked state. [Figure 8] FIG. 13 is a diagram illustrating a locking mechanism in an unlocked state. [Figure 9] FIG. 13 is a diagram for explaining an index according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] An X-ray CT (Computed Tomography) apparatus according to one embodiment of the present invention will be described.

[0022] First, the overall structure of the X-ray CT apparatus of this embodiment will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is an external view of the X-ray CT apparatus 1, and Fig. 2 is a block diagram showing the overall structure. As shown in Figs. 1 and 2, the X-ray CT apparatus 1 includes a gantry 100, a bed 105, and an operation unit 120.

[0023] The gantry 100 includes a rotating disk unit 102 , a gantry controller 108 , a bed controller 109 , and an X-ray controller 110 .

[0024] The three-dimensional coordinate system shown in FIG. 1 shows an example of the definition of directions in the X-ray CT scanner 1. The X-axis, Y-axis, and Z-axis of the three-dimensional coordinate system are just an example, and are not limited to this. For ease of understanding in the following description, the X-axis, Y-axis, and Z-axis in the X-ray CT scanner 1 are defined in the same direction in all figures. The Z-axis direction is the body axis direction of the subject. The Y-axis direction is the up-down direction of the subject, and is parallel to the direction of gravity. The X-axis direction is the left-right direction of the subject, and is the horizontal direction perpendicular to the direction of gravity.

[0025] The rotating disk unit 102 includes a rotating frame 40 with an opening 104, and an X-ray tube 51, a collimator 103, and an X-ray detection unit 56 mounted on the rotating frame 40. A subject 2 placed on a bed 105 enters the opening 104 of the rotating frame 40. The rotating disk unit 102 rotates around the subject 2. The rotating disk unit 102 has a tilt mechanism that rotates the rotating disk unit 102 while tilting the direction of the rotation axis with respect to the main plane of the top board of the bed 105.

[0026] The gantry 100 accommodates the rotating disk unit 102 and other components in a housing (gantry cover) 101 as shown in FIG.

[0027] The X-ray tube 51 is a device that irradiates X-rays to the subject 2 placed on the bed 105. The collimator 103 is a device that limits the radiation range of X-rays irradiated from the X-ray tube 51. The X-ray detection unit 56 includes an X-ray detector 256a and a data collection device 256b. The X-ray detector 256a is a device that is arranged opposite the X-ray tube 51 on the rotating frame 40 and measures the spatial distribution of the transmitted X-rays by detecting the X-rays that have passed through the subject. The X-ray detector 256a is a device that has a large number of X-ray detection elements arranged in the rotation direction of the rotating frame 40, or that has a two-dimensional arrangement in the rotation direction and the rotation axis direction of the rotating frame 40. The data collection device 256b is a device that collects the amount of X-rays detected by the X-ray detector 256a as digital data.

[0028] The gantry control device 108 is a device that controls the rotation of the rotating disk unit 102, and a control unit 55 that is a part of it is mounted on the rotating frame 40. The bed control device 109 is a device that controls the up-down and forward-backward movement of the bed 105.

[0029] The X-ray controller 110 is a device that controls the power input to the X-ray tube 51. The high-voltage generating units 53 and 54 and the cooling device 52, which are part of the X-ray controller 110, are mounted on the rotating frame 40.

[0030] The operation unit 120 includes an input device 121, an image calculation device 122, a display device 125, a storage device 123, and a system control device 124. The input device 121 is a device for inputting the subject's name, the examination date and time, the imaging conditions, and the like. The input device 121 is specifically a keyboard or a pointing device. The image calculation device 122 is a device for performing CT image reconstruction by calculating and processing the measurement data sent from the data collection device 256b of the X-ray detection unit 56. The display device 125 is a device for displaying the CT image created by the image calculation device 122, and is, for example, a liquid crystal display. The storage device 123 is a device for storing the data collected by the data collection device 256b and the image data of the CT image created by the image calculation device 122, and is, for example, a HDD (Hard Disk Drive). The system control device 124 is a device for controlling these devices, the gantry control device 108, the bed control device 109, and the X-ray control device 110.

[0031] The structure of the gantry 100 will be described with reference to FIGS.

[0032] FIG. 3 is an external view of the gantry 100, in which 3-1 in FIG. 3 is a front view, 3-2 in FIG. 3 is a side view, and 3-3 in FIG. 3 is a rear view. As shown in FIG. 3, the gantry 100 accommodates the rotating disk unit 102 and the like in a housing (gantry cover) 101. The gantry cover 101 is composed of a plurality of individual gantry covers. For example, the plurality of individual gantry covers include a front cover 101a, an upper cover 101b, a side cover 101c, a first rear cover 101d, and a second rear cover 101e. By configuring the gantry cover 101 with a plurality of individual gantry covers, the assembly and workability of the rotating disk unit 102 and the like can be improved. The front cover 101a is composed of an integral part. The rotating disk unit 102 and the like can be exposed by removing the front cover 101a.

[0033] Fig. 4 is a front view of the rotating disk unit 102 with the front cover 101a removed. Fig. 5 is a front view of the rotating disk unit 102 with the rotating frame 40 removed from the rotating disk unit 102 in Fig. 4.

[0034] The gantry 100 includes a gantry cover 101 and a rotating disk unit 102 (see FIG. 2, etc.) disposed inside the gantry cover 101. The rotating disk unit 102 includes a rotating frame 40 having an opening 104, a fixed frame 30 that supports the rotating frame 40 from the rear side via a bearing (not shown), and a stand 10 that supports the fixed frame 30.

[0035] The rotating frame 40 of the rotating disk unit 102 is supported by the fixed frame 30 so as to be rotatable around the rotation axis Ax. The rotating frame 40 is connected to a large pulley (not shown) via the rotating part side (inner thread) of a bearing. The large pulley is disposed on the rear side of the rotating frame 40. A drive belt 7 is wound around the outer periphery of the large pulley. A motor 11 is fixed to a position below the gantry 100 shown in FIG. 4 and close to the stand 10 on the right side. A small pulley (not shown) is connected to the rotating shaft (not shown) of the motor 11. The drive belt 7 is also wound around the small pulley.

[0036] The motor 11 drives the small pulley to rotate, thereby driving the drive belt 7. The driving of the drive belt 7 rotates the large pulley, which rotates the rotating side (inner wheel) of the bearing. The large pulley rotates the bearing, which drives the rotating frame 40 to rotate about the rotation axis Ax.

[0037] The rotating frame 40 has a substantially octagonal shape in a front view. The rotating frame 40 is equipped with an X-ray tube 51, an X-ray detection unit 56, a cooling device 52, a control unit 55, and high voltage generating units 54 and 53. That is, the rotating frame 40 is equipped with a plurality of components including the X-ray tube 51 and the X-ray detection unit 56. In FIG. 4, the plurality of components are fixed by bolts at positions corresponding to the sides of the substantially octagonal rotating frame 40. The X-ray tube 51 is an example of an X-ray source of the present invention. The X-ray detector 256a is an example of an X-ray detector of the present invention. The X-ray tube 51, the X-ray detection unit 56, the cooling device 52, the control unit 55, and the high voltage generating units 54 and 53 are an example of a plurality of components of the present invention. One locking mechanism 60 is disposed on the rotating frame 40.

[0038] As shown in Fig. 5, the fixed frame 30 is disposed on the rear side of the rotating frame 40. The fixed frame 30 has, for example, a substantially octagonal shape when viewed from the front. An outer ring (not shown), which is the fixed portion side of a bearing, is disposed on the fixed frame 30 so as to surround an opening 104. The fixed frame 30 is an example of a support frame of the present invention. The rotating frame 40 is an example of a rotating frame of the present invention.

[0039] The fixing frame 30 has one or more fixing holes 32, specifically, eight fixing holes 32 formed therein.

[0040] The imaging operation of the X-ray CT device 1 will be briefly described. The imaging conditions, particularly the X-ray tube voltage and the X-ray tube current, are input from the input device 121. The rotating frame 40 rotates around the subject 2. The X-ray control device 110 controls the power input to the X-ray tube 51 based on the imaging conditions. The X-ray tube 51 irradiates the subject with X-rays according to the imaging conditions. The X-ray detection unit 56 detects the X-rays irradiated from the X-ray tube 51 and transmitted through the subject with a large number of X-ray detection elements of the X-ray detector 256a. The distribution of the transmitted X-rays is measured from the detection results. The rotation speed, the angle (tilt) of the rotation axis, etc. of the rotating disk unit 102 are set to the imaging conditions input from the input device 121 by the gantry control device 108. The rotation and stop of the rotating frame 40 are performed by the rotation drive of the drive belt 7 by the motor 11 and the stop of the drive belt 7 by a brake (not shown). The gantry control device 108 controls the operation of the motor 11 and the operation of the brake. The bed 105 is controlled by a bed control device 109 and operates based on the imaging conditions, particularly the helical pitch, inputted from an input device 121 .

[0041] X-ray irradiation from the X-ray tube 51 and measurement of the transmitted X-ray distribution by the X-ray detection unit 56 are repeated as the rotating frame 40 rotates. As a result, projection data from various angles is acquired by the data acquisition device 256b. The acquired projection data from various angles is transmitted to the image calculation device 122. The image calculation device 122 reconstructs a CT image by performing back projection processing on the transmitted projection data from various angles. The reconstructed CT image is displayed on the display device 125.

[0042] When performing maintenance such as replacing the X-ray tube 51 or the X-ray detection unit 56, the power to the rotation drive devices such as the motor 11 is turned off, and then the gantry cover 101 is removed. The rotating frame 40 is placed in a locked state in which rotation is restricted by the locking mechanism 60. The X-ray tube 51 and the like are removed from the locked rotating frame 40, and replacement or the like is performed. When maintenance is completed, the rotating frame 40 is placed in an unlocked state by the locking mechanism 60 so that it can rotate, and the X-ray CT device 1 starts normal imaging operation.

[0043] <Lock mechanism> Next, a description will be given of the structure of the lock mechanism 60 and the fixing holes 32 that switch the rotating frame 40 between the locked state and the unlocked state. Fig. 6 is a diagram showing a state in which the rotating frame 40 is locked by the lock mechanism 60. Figs. 7 and 8 are diagrams for explaining the operation of the lock mechanism 60.

[0044] In the locked state of the rotating frame 40 shown in Fig. 6, the X-ray tube 51, which is the part subject to maintenance, is located below the rotation axis Ax. During maintenance, positioning the part subject to maintenance below the rotation axis Ax facilitates work such as removing and replacing the part. In Fig. 6, the locking mechanism 60 has been moved to a position facing the second fixing hole 32 from the top on the left side (the position of 32-7: see Fig. 5) so that the X-ray tube 51 is located below the rotation axis Ax.

[0045] Fig. 7 shows a locked state in which the rotating frame 40 is restricted from rotating, and Fig. 8 shows an unlocked state in which the rotating frame 40 is rotatable. In the locking mechanism 60 of the embodiment, the rotating frame 40 is locked by engaging the fixed shaft 61 of the locking mechanism 60 with the fixing hole 32, and the rotating frame 40 is in a locked state in which rotation is restricted. Furthermore, when the engagement between the fixed shaft 61 of the locking mechanism 60 and the fixing hole 32 is released, the rotating frame 40 is in an unlocked state in which it is rotatable.

[0046] The fixed shaft 61 is an example of the fixed shaft of the present invention. The fixing hole 32 is an example of the lock fixing portion of the present invention. As long as the lock fixing portion can engage with the fixed shaft 61, the shape thereof is not limited and may be a groove, a recess, or the like.

[0047] 7 and 8, the locking mechanism 60 includes a fixed shaft 61 and a support member 62 that movably supports the fixed shaft 61. The fixed shaft 61 is a cylindrical rod-shaped member. The outer diameter of the fixed shaft 61 is large enough to allow it to be inserted into the fixed hole 32. The fixed shaft 61 is inserted into the fixed hole 32, and the fixed shaft 61 and the fixed hole 32 engage with each other. The fixed shaft 61 is disposed in a direction along the Z-axis.

[0048] The side of the fixed shaft 61 that is not engaged with the fixing hole 32 is movably inserted into a block body 63. The block body 63 supports the fixed shaft 61. The block body 63 has a substantially rectangular parallelepiped shape. The block body 63 is attached to the control unit 55 in a state where it cannot move relative to the control unit 55.

[0049] The support member 62 is movably attached to the control unit 55. As described above, the control unit 55 is one of the parts mounted on the rotating frame 40. The support member 62 has a shape obtained by bending a plate-like member. The support member 62 has a plurality of flat portions. The support member 62 has a connecting surface 64 that is connected to the fixed shaft 61 block body 63. The connecting surface 64 is provided so as to face the fixed frame 30.

[0050] The support member 62 has a moving surface 65 movably attached to the control unit 55. The moving surface 65 extends along the Z-axis direction. The connecting surface 64 and the moving surface 65 are positioned so as to be substantially perpendicular to each other. A first oblong hole 66 and a second oblong hole 67 are formed in the moving surface 65. The first oblong hole 66 and the second oblong hole 67 extend along the Z-axis direction.

[0051] Two guide pins 68 are inserted into the first long hole 66. The guide pins 68 allow the moving surface 65 to move smoothly in the direction of arrow A or arrow B along the first long hole 66. Direction A is the direction in which the rotating frame 40 is locked, and direction B is the direction in which the rotating frame 40 is unlocked. A fixing screw 69 is inserted into the second long hole 67. By fastening the fixing screw 69, the moving surface 65 can be fixed to the control unit 55 in an unmovable state. By changing the fastening position of the moving surface 65 relative to the fixing screw 69, it is possible to switch between the locked state and the unlocked state. The fixing screw 69 is provided in a state in which it cannot move relative to the control unit 55.

[0052] The support member 62 has an access surface 70 at a position facing the second elongated hole 67. A first through hole 71 and a second through hole 72 are formed in the access surface 70. The access surface 70 is supported by a support surface 73 connected to the moving surface 65. The first through hole 71 or the second through hole 72 allows access to the fixing screw 69 only when the axial direction of the first through hole 71 or the second through hole 72 coincides with that of the fixing screw 69. Therefore, an operator can tighten or loosen the fixing screw 69 with a tool via the first through hole 71 or the second through hole 72.

[0053] Support member 62 has a first fixed surface 74 on the opposite side of connecting surface 64 with respect to moving surface 65. First fixed surface 74 is fixed in a state in which it cannot move relative to control unit 55. A second fixed surface 75 extending along the Z-axis direction is connected to first fixed surface 74. First fixed surface 74 and second fixed surface 75 are approximately L-shaped when viewed from the Z-axis direction.

[0054] A first fixed pin 76 is provided on the support surface 73. The first fixed pin 76 is approximately perpendicular to the support surface 73. A second fixed pin 77 is provided on the second fixed surface 75. The second fixed pin 77 is approximately perpendicular to the second fixed surface 75. One end of a tension spring 80 is connected to the first fixed pin 76. The other end of the tension spring 80 is connected to the second fixed pin 77. The tension spring 80 biases the moving surface 65 toward the first fixed surface 74 (in the direction of arrow B). That is, the tension spring 80 biases the moving surface 65 toward the first fixed surface 74 in a direction in which the engagement between the fixed shaft 61 and the fixed hole 32 is released (so as to reach an unlocked state). The tension spring 80 is an example of an elastic member of the present invention.

[0055] It should be noted that a compression spring can be used as the elastic member instead of the tension spring 80. Also, the moving surface 65 may be moved by a screw instead of the tension spring 80. As long as the moving surface 65 can move between the locked position and the unlocked position, the means for moving the moving surface 65 is not particularly limited.

[0056] 7, against the tensile force of the tension spring 80, the moving surface 65 is moved to a position where the fixed shaft 61 and the fixing hole 32 engage with each other, and is fixed to the control unit 55 by a fixing screw 69. In other words, the moving surface 65 (support member 62) is fixed at a position (lock position) where the rotating frame 40 is put into a locked state.

[0057] 8, the tension of the tension spring 80 moves the moving surface 65 to a position where the fixed shaft 61 is disengaged from the fixing hole 32, and the moving surface 65 is fixed to the control unit 55 by a fixing screw 69. That is, the moving surface 65 (support member 62) is fixed at a position (unlocked position) where the rotating frame 40 is in an unlocked state. The tension spring 80 pulls the moving surface 65 in the direction of the unlocked position, so that it is possible to prevent the fixed shaft 61 from engaging with the fixing hole 32 while the X-ray CT apparatus 1 is in operation.

[0058] 7 and 8, the longitudinal axis of the fixed shaft 61 and the longitudinal axis of the moving surface 65 of the support member 62 are offset by a distance L1 when viewed from the Z-axis direction (the moving direction of the fixed shaft 61 and the moving surface 65). Because the fixed shaft 61 is offset with respect to the moving surface 65 (support member 62), the operator can easily check the positional relationship between the fixed shaft 61 and the fixing hole 32.

[0059] 9A and 9B are diagrams for explaining the indexes of the embodiment, in which 9-1 in Fig. 9 is a diagram showing the locked state, and 9-2 in Fig. 9 is a diagram showing the unlocked state.

[0060] The second fixed surface 75 has a first notch 78 and a second notch 79 on the side opposite to the first fixed surface 74. The first notch 78 and the second notch 79 are spaced apart in the Z-axis direction. The support surface 73 has an index surface 81 extending toward the second fixed surface 75. The index surface 81 has a third notch 82 facing the second fixed surface 75. The combination of the first notch 78, the second notch 79, and the third notch 82 serves as an indicator showing whether the support member 62 is in a position that causes the rotating frame 40 to be in a locked state or in a position that causes the rotating frame 40 to be in an unlocked state.

[0061] As shown in 9-1, in the locked state, the first notch 78 and the third notch 82 are positioned to face each other when viewed from the axial direction of the first fixing pin 76 and the second fixing pin 77. In other words, when the first notch 78 and the third notch 82 face each other, the operator can recognize that the moving surface 65 is in the locked position where the fixed shaft 61 and the fixing hole 32 are engaged with each other.

[0062] As shown in 9-2, in the unlocked state, the second notch 79 and the third notch 82 are positioned to face each other when viewed from the axial direction of the first fixing pin 76 and the second fixing pin 77. In other words, when the second notch 79 and the third notch 82 face each other, the operator can recognize that the moving surface 65 is in the unlocked position where the engagement between the fixed shaft 61 and the fixing hole 32 is released.

[0063] The first notch 78, the second notch 79, and the third notch 82 are examples of the indicators of the present invention. In the embodiment of FIG. 9, a case where notches are used as the indicators has been described. However, the indicators are not limited to notches as long as they indicate whether the state is locked or unlocked. For example, the indicators may be grooves, protrusions, or printed marks provided on the second fixing surface 75 and the indicator surface 81.

[0064] Also, as shown in 9-1, when the moving surface 65 (support member 62) is positioned in the locked position, the first through hole 71 of the access surface 70 and the axial direction of the fixing screw 69 are aligned, so that the operator can access the fixing screw 69 through the first through hole 71.

[0065] Furthermore, as shown in 9-2, when the moving surface 65 (support member 62) is positioned in the unlocked position, the second through hole 72 of the access surface 70 and the axial direction of the fixing screw 69 coincide with each other, so that the operator can access the fixing screw 69 via the second through hole 72. In other words, only when the moving surface 65 is positioned in the locked position or the unlocked position, the operator can access the fixing screw 69 via the first through hole 71 or the second through hole 72 of the access surface 70. The moving surface 65 (support member 62) can be fixed only in the locked position or the unlocked position.

[0066] The distance L2 between the head of the fastening screw 69 and the access surface 70 is shorter than the length of the fastening screw 69. The opening diameter of the first through hole 71 and the second through hole 72 is smaller than the diameter of the head of the fastening screw 69. The access surface 70 in which the first through hole 71 and the second through hole 72 are formed functions to prevent the fastening screw 69 from coming loose. During maintenance, the locking mechanism 60 is moved to a position facing one of the eight fastening holes 32, and the fastening shaft 61 and the fastening hole 32 are engaged. At that time, regardless of the position of the fastening hole 32 to which the locking mechanism 60 is moved, the access surface 70 prevents the fastening screw 69 from falling during the work. As a result, the workability of the maintenance can be improved.

[0067] Next, a description will be given of the relationship between the combination of the locked state in which any one of the eight fixing holes 32 is engaged with the fixed shaft 61 and the maintenance parts positioned at the work position. In the following description, the work position is below the rotation axis Ax. Table 1 shows combinations of the positions of the fixing holes 32 with which the fixed shaft 61 engages and the names of the parts positioned at the work position, based on the structure of the gantry 100 shown in Figures 4 to 6.

[0068] In Table 1, based on FIG. 5, the positions of the fixing holes 32 are defined as 32-1 to 32-8 clockwise from the upper right position.

[0069] [Table 1] In Table 1, for example, (fixing hole position: 32-1, part name: high voltage generating unit) indicates that when fixed shaft 61 of locking mechanism 60 is engaged with fixing hole 32 at position 32-1, high voltage generating unit 54 is positioned at the working position. Fig. 6 corresponds to (fixing hole position: 32-7, part name: X-ray tube) and indicates that when fixed shaft 61 of locking mechanism 60 is engaged with fixing hole 32 at position 32-7, X-ray tube 51 is positioned at the working position.

[0070] The lock mechanism 60 is preferably provided at a location that satisfies the conditions that the fixed shaft 61 can be engaged with the fixing hole 32 above the rotation axis Ax and that a component that is frequently replaced can be positioned below the rotation axis Ax. The component that is frequently replaced is the X-ray tube 51, and the fixing hole 32 above the rotation axis Ax is, for example, the fixing hole 32 at the position 32-1, 32-2, 32-7, or 32-8.

[0071] 6, the lock mechanism 60 is provided at a position adjacent to the control unit 55 in the clockwise direction in a front view. By providing the lock mechanism 60 at this position, the fixed shaft 61 can be engaged with the fixing hole 32 at the position 32-7, and the X-ray tube 51 can be positioned at the working position.

[0072] 4 or 6, the locking mechanism 60 may be provided at a position adjacent to the high voltage generating unit 54 in the counterclockwise direction in front view. In this case, the fixed shaft 61 can engage with the fixing hole 32 at the position 32-2, and the X-ray tube 51 is positioned at the working position. Note that when the locking mechanism 60 is provided at a position different from that in FIG. 4 or 6, the combination of the position of the fixing hole 32 and the part name will be different from that in Table 1.

[0073] By arranging the fixed shaft 61 facing the fixing hole 32 above the rotation axis Ax, the worker can engage the fixed shaft 61 with the fixing hole 32 at eye level. That is, the ease of maintenance work can be improved for the worker. In particular, the burden of engagement work for parts that require frequent maintenance can be reduced. The working position has been described as being below the rotation axis Ax. However, depending on the device, the unit may be positioned at a position (working position) above the rotation axis Ax to perform maintenance work on the unit. That is, as long as the device can be positioned at a position desired by the worker, the working position may be either above or below the rotation axis Ax.

[0074] It is also preferable to improve safety during maintenance. For example, when the fixed shaft 61 and the fixing hole 32 are engaged and the rotating frame 40 is in a locked state, it is preferable to turn off the power supply to the motor 11. This makes it possible to prevent the rotating frame 40 from being rotated when the fixed shaft 61 and the fixing hole 32 are engaged, since the power supply to the motor 11 is turned off. The engagement state between the fixed shaft 61 and the fixing hole 32 can be detected by providing a sensor (not shown). A detection signal from the sensor is transmitted to the gantry control device 108, which then turns off the power supply to the motor 11. When the rotating frame 40 is in a locked state, the rotating frame 40 is not rotated, so the safety of the operator can be ensured. The gantry control device 108 is an example of a processor of the present invention.

[0075] Once the power supply to the motor 11 is turned off, the power supply to the motor 11 remains off even if the engagement between the fixed shaft 61 and the fixing hole 32 is released. This makes it possible to prevent the motor 11 from being suddenly rotated by the rotating frame 40. When turning the power supply on, the operator manually turns on the power supply to the motor 11.

[0076] Even if the rotating frame 40 is rotated at the maximum output of the motor 11 with the fixed shaft 61 engaged with the fixing hole 32, the fixed shaft 61 has enough strength not to be broken. The fixed shaft 61 can maintain its engagement with the fixing hole 32, and the locked state of the rotating frame 40 is maintained. Even if the motor 11 rotates the rotating frame 40, the fixed shaft 61 maintains the rotating frame 40 in the locked state, ensuring the safety of the operator.

[0077] In the embodiment, a plurality of fixing holes 32 and one locking mechanism 60 have been described. However, the present invention is not limited to this, and one fixing hole 32 and one or more locking mechanisms 60 may be provided. For example, eight locking mechanisms 60 may be provided on each side of the substantially octagonal rotating frame 40. One fixing hole 32 may be provided above the rotation axis Ax. Therefore, when positioning any replacement part at the work position, the worker can operate the locking mechanism 60 at eye level. Furthermore, the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications are possible. [Explanation of symbols]

[0078] 30 fixed frame, 32 fixing hole, 40 rotating frame, 55 control section, 56 X-ray detection unit, 60 lock mechanism, 61 fixed shaft, 62 support member, 63 block body, 64 connection surface, 65 moving surface, 66 first oblong hole, 67 second oblong hole, 68 guide pin, 69 fixing screw, 70 access surface, 71 first through hole, 72 second through hole, 73 support surface, 74 first fixing surface, 75 second fixing surface, 76 first fixing pin, 77 second fixing pin, tension spring 80

Claims

1. A rotating frame that rotates while mounting a plurality of components including an X-ray source and an X-ray detector, a support frame that rotatably supports the rotating frame, the support frame has one or more locking mechanisms including a fixed shaft and a support member that movably supports the fixed shaft; The support frame has one or more lock fixing portions engageable with the fixed shaft, The locking mechanism switches between a locked state that restricts rotation of the rotating frame and an unlocked state that allows rotation of the rotating frame.

2. 2. The X-ray CT apparatus according to claim 1, wherein in a locked state in which a fixed shaft of the lock mechanism and the lock fixing portion are engaged with each other, any one of the plurality of components is positioned at a position below the rotation shaft of the rotating frame.

3. The X-ray CT apparatus according to claim 2 , wherein any one of the plurality of components is the X-ray source.

4. The X-ray CT apparatus according to claim 1 , wherein the one or more locking fixing portions include a plurality of locking fixing portions.

5. 5. The X-ray CT apparatus according to claim 4, wherein any one of the plurality of components is positioned at a predetermined position according to a combination of lock states in which one of the plurality of lock fixing portions is engaged with a fixed shaft of the lock mechanism.

6. The X-ray CT apparatus according to claim 1 , wherein the one or more locking mechanisms include a plurality of locking mechanisms.

7. 7. The X-ray CT apparatus according to claim 6, wherein any one of the plurality of components is positioned at a predetermined position according to a combination of lock states in which a fixed shaft of one of the plurality of lock mechanisms is engaged with the lock fixing portion.

8. The X-ray CT apparatus according to claim 1 , wherein the fixed axis is disposed offset relative to the support member.

9. 4. The X-ray CT apparatus according to claim 1, wherein the locking mechanism includes an index that indicates whether the support member is in a position for locking or unlocking the rotating frame.

10. 4. The X-ray CT apparatus according to claim 1, wherein the locking mechanism includes an elastic member that biases the support member to a position where the rotating frame is in an unlocked state.

11. 4. The X-ray CT apparatus according to claim 1, further comprising a motor that rotates the rotating frame, and a processor that turns off a power supply to the motor when the rotating frame is in a locked state.

12. 12. The X-ray CT apparatus according to claim 11, wherein, in a state in which said fixed shaft is engaged with said lock fixing portion, said fixed shaft can maintain said rotating frame in a locked state against a maximum output of said motor.

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