JPWO2012026381A1 - X-ray tube apparatus and X-ray CT apparatus - Google Patents

Abstract

In order to provide an X-ray tube apparatus having a structure capable of improving the cooling efficiency of the X-ray tube and preventing overheating of the rotary bearing in particular, and to provide an X-ray CT apparatus equipped with the X-ray tube apparatus, an electron beam A cathode that emits X-rays by being disposed opposite to the cathode and irradiated with the electron beam, an envelope that holds the cathode and the anode in a vacuum atmosphere, and the anode is rotated. An X-ray tube device having an anode rotation driving unit, wherein the anode has a double-layered cylindrical portion on the back side of the surface facing the cathode, and the inside of the cylindrical portion The cylindrical portion is connected to a rotary bearing, and the outer cylindrical portion of the cylindrical shape portion has a length to reach the vicinity of the envelope, and is connected to the rotary cylindrical bearing. Heat transfer from the outer cylindrical portion to the envelope is promoted so as to suppress heat transfer.

Description

  The present invention relates to an X-ray tube apparatus and an X-ray CT (Computed Tomography) apparatus.

  An X-ray CT device is an X-ray tube device that irradiates a subject with X-rays, and an X-ray detector that detects X-ray dose transmitted through the subject as projection data by rotating the subject around the subject. The tomographic image of the subject is reconstructed using the obtained projection data from a plurality of angles, and the reconstructed tomographic image is displayed. The image displayed by the X-ray CT apparatus describes the shape of an organ in the subject and is used for diagnostic imaging.

  In recent developments of X-ray CT apparatuses, the imaging time has been shortened by rotating a scanner equipped with an X-ray tube apparatus and an X-ray detector at a higher speed. In order to maintain the image quality of tomographic images even when the scanner rotates at high speed, it is necessary to increase the X-ray dose per unit time generated from the X-ray tube device. To increase the X-ray dose, the tube current must be increased and the amount of heat generated in the X-ray tube increases. The amount of heat generated in the X-ray tube has several adverse effects on the X-ray tube. For example, the cause of harmful effects such as melting of the X-ray target due to overheating of the anode, misalignment of the X-ray focal point due to thermal expansion of the rotating shaft of the anode, and rotation failure due to overheating of the solid lubricant used in the rotating bearing of the anode Become.

  Therefore, in order to prevent the harmful effects that can occur in the X-ray tube, various improvements have been made to the structure of the X-ray tube to improve the cooling efficiency. For example, Patent Document 1 discloses an X-ray tube device in which the cooling efficiency by heat radiation is improved by providing a cylindrical radiator on the cathode facing surface side of the rotating anode.

Japanese Patent Laid-Open No. 10-334840

  However, although Patent Document 1 discloses an X-ray tube apparatus with improved cooling efficiency by heat radiation, no consideration is given to preventing overheating of the rotary bearing.

  Therefore, an object of the present invention is to provide an X-ray tube apparatus having a structure capable of improving the cooling efficiency of the X-ray tube, and particularly preventing the overheating of the rotary bearing, and an X-ray CT apparatus equipped with the X-ray tube apparatus. Is to provide.

  In order to achieve the above object, the present invention provides a double-structured cylindrical portion on the back surface of the cathode facing surface of the rotating anode, and suppresses heat transfer to the inner cylindrical portion connected to the rotating bearing. The heat transfer from the cylindrical portion to the envelope is promoted.

  Specifically, a cathode that generates an electron beam, an anode that is disposed opposite to the cathode and emits X-rays when irradiated with the electron beam, and an envelope that holds the cathode and the anode in a vacuum atmosphere And an X-ray tube device having an anode rotation driving unit for rotating the anode, the anode having a double-structured cylindrical portion on the back side of the surface facing the cathode, An inner cylindrical portion of the cylindrical portion is connected to a rotary bearing, and the outer cylindrical portion of the cylindrical portion has a length that reaches the vicinity of the outer enclosure. It is.

  In addition, the X-ray tube device, the X-ray detector that is disposed opposite to the X-ray tube device and detects X-rays transmitted through the subject, the X-ray tube device and the X-ray detector are mounted, and the target is mounted. A rotating disk that rotates around the specimen, an image reconstruction device that reconstructs a tomographic image of the subject based on transmitted X-ray doses from a plurality of angles detected by the X-ray detector, and the image reconstruction device. An X-ray CT apparatus comprising: an image display device that displays a reconstructed tomographic image.

  According to the present invention, an X-ray tube apparatus having a structure capable of improving the cooling efficiency of the X-ray tube and preventing overheating of the rotary bearing in particular, and an X-ray CT apparatus equipped with the X-ray tube apparatus are provided. can do.

The block diagram which shows the whole structure of the X-ray CT apparatus of this invention The block diagram which shows the whole structure of the X-ray tube apparatus of this invention Sectional drawing which shows the structure around the rotor of 1st embodiment Enlarged view of the envelope on the anode side of the first embodiment Sectional drawing which shows the structure around the rotor of 2nd embodiment Sectional drawing which shows the structure around the rotor of 3rd embodiment Sectional drawing which shows the structure around the rotor of 4th embodiment

  Hereinafter, preferred embodiments of an X-ray CT apparatus according to the present invention will be described with reference to the accompanying drawings. In the following description and the accompanying drawings, the same reference numerals are given to the constituent elements having the same functional configuration, and redundant description will be omitted.

  The overall configuration of the X-ray CT apparatus 1 to which the present invention is applied will be described with reference to FIG. The X-ray CT apparatus 1 includes a scan gantry unit 100 and a console 120.

  The scan gantry unit 100 includes an X-ray tube device 101, a rotating disk 102, a collimator 103, an X-ray detector 106, a data collection device 107, a bed 105, a gantry control device 108, and a bed control device 109. An X-ray control device 110. The X-ray tube device 101 is a device that irradiates a subject placed on a bed 105 with X-rays. The collimator 103 is a device that limits the radiation range of X-rays emitted from the X-ray tube device 101. The rotating disk 102 includes an opening 104 into which the subject placed on the bed 105 enters, and is equipped with an X-ray tube device 101 and an X-ray detector 106, and rotates around the subject. The X-ray detector 106 is a device that measures the spatial distribution of transmitted X-rays by detecting X-rays that are disposed opposite to the X-ray tube device 101 and transmitted through the subject. The rotating disk 102 is arranged in the rotating direction, or the rotating disk 102 is arranged two-dimensionally in the rotating direction and the rotating shaft direction. The data collection device 107 is a device that collects the X-ray dose detected by the X-ray detector 106 as digital data. The gantry control device 108 is a device that controls the rotation of the rotary disk 102. The bed control device 109 is a device that controls the vertical movement of the bed 105. The X-ray control device 110 is a device that controls electric power input to the X-ray tube device 101.

  The console 120 includes an input device 121, an image arithmetic 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 a subject's name, examination date and time, imaging conditions, and the like, specifically a keyboard or a pointing device. The image computation device 122 is a device that performs CT processing on the measurement data sent from the data collection device 107 and performs CT image reconstruction. The display device 125 is a device that displays the CT image created by the image calculation device 122, and is specifically a CRT (Cathode-Ray Tube), a liquid crystal display, or the like. The storage device 123 is a device that stores data collected by the data collection device 107 and image data of a CT image created by the image calculation device 122, and is specifically an HDD (Hard Disk Drive) or the like. The system control device 124 is a device that controls these devices, the gantry control device 108, the bed control device 109, and the X-ray control device 110.

  The X-ray tube device 101 is controlled by the X-ray controller 110 controlling the power input to the X-ray tube device 101 based on the imaging conditions input from the input device 121, in particular, the X-ray tube voltage and the X-ray tube current. Irradiates the subject with X-rays according to imaging conditions. The X-ray detector 106 detects X-rays irradiated from the X-ray tube apparatus 101 and transmitted through the subject with a large number of X-ray detection elements, and measures the distribution of transmitted X-rays. The rotating disk 102 is controlled by the gantry control device 108, and rotates based on the photographing conditions input from the input device 121, particularly the rotation speed. The couch 105 is controlled by the couch controller 109 and operates based on the photographing conditions input from the input device 121, particularly the helical pitch.

  By repeating the X-ray irradiation from the X-ray tube device 101 and the measurement of the transmitted X-ray distribution by the X-ray detector 106 along with the rotation of the rotating disk 102, projection data from various angles is acquired. The acquired projection data from various angles is transmitted to the image calculation device 122. The image calculation device 122 reconstructs the CT image by performing back projection processing on the transmitted projection data from various angles. The CT image obtained by the reconstruction is displayed on the display device 125.

  Depending on the size of the opening 104 of the rotating disk 102 and the thickness of the scan gantry unit 100, the subject may feel a sense of pressure. Therefore, it is desirable that the opening 104 is large and the scan gantry unit 100 is thin. Since the size of the opening 104 and the thickness of the scan gantry unit 100 depend on the size of the mounted object of the rotating disk 102, it is preferable that the X-ray tube device 101 which is one of the mounted objects is smaller.

  The configuration of the X-ray tube apparatus 101 will be described with reference to FIG. The X-ray tube apparatus 101 includes an X-ray tube 210 that generates X-rays and a container 220 that stores the X-ray tube 210.

  The X-ray tube 210 includes a cathode 211 that generates an electron beam, an anode 212 to which a positive potential is applied to the cathode 211, and an envelope 213 that holds the cathode 211 and the anode 212 in a vacuum atmosphere.

  The cathode 211 includes a filament or a cold cathode and a focusing electrode. The filament is formed by winding a high melting point material such as tungsten in a coil shape, and is heated when a current is passed to emit thermoelectrons. A cold cathode is formed by sharpening a metal material such as nickel or molybdenum, and emits electrons by field emission when an electric field is concentrated on the cathode surface. The focusing electrode forms a focusing electric field for focusing the emitted electrons toward the X-ray focal point 216 on the anode 212. The filament or cold cathode and the focusing electrode are at the same potential.

  The anode 212 includes a target and an anode base material. The target is made of a material having a high melting point and a large atomic number, such as tungsten. X-rays 217 are emitted from the X-ray focal point 216 when electrons emitted from the cathode 211 collide with the X-ray focal point 216 on the target. The anode base material holds the target and is made of a material having high thermal conductivity such as copper. The target and the anode base material are at the same potential.

  The envelope 213 maintains the cathode 211 and the anode 212 in a vacuum atmosphere in order to electrically insulate the cathode 211 and the anode 212 from each other. The envelope 213 is provided with a radiation window 218 for emitting X-rays 217 to the outside of the X-ray tube 210. The radiation window 218 is made of a material having a small atomic number such as beryllium having a high X-ray transmittance. The potential of the envelope 213 is the ground potential, and the anode 212 is also the same potential. That is, a negative high potential is applied to the cathode 211.

  Electrons emitted from the cathode 211 are accelerated by a voltage of about 100 kV applied between the cathode and the anode to become an electron beam 215. When the electron beam 215 is focused by the focusing electric field and collides with the X-ray focal point 216 on the target, X-rays 217 are generated from the X-ray focal point 216. The energy of the generated X-ray is determined by a high voltage applied between the cathode and the anode, so-called tube voltage. The dose of X-rays generated depends on the amount of electrons emitted from the cathode, the so-called tube current and the tube voltage.

  Of the energy of the electron beam 215, the ratio of being converted to X-rays is only about 1%, and most of the remaining energy is heat. In the X-ray tube apparatus 101 used in the X-ray CT apparatus 1, since the tube voltage is several hundreds kV and the tube current is several hundred mA, the anode 212 is heated with a heat quantity of several tens kW. In order to prevent the anode 212 from being overheated and melted by such heating, the anode 212 is connected to the rotating device 214 and is rotated about the one-dot chain line 219 in FIG. . The rotating device 214 holds an exciting coil 214A that generates a magnetic field that serves as a rotational driving force, a rotor 214B that rotates by receiving the magnetic field generated by the exciting coil 214A, a bearing that rotatably supports the rotor 214B, and a bearing. A stator 214C. The bearing will be described in FIG. The stator 214C is supported by the envelope 213. The rotation axis of the anode 212 is hereinafter referred to as a tube axis 219 of the X-ray tube 210.

  By rotating the anode 212, the X-ray focal point 216 where the electron beam 215 collides always moves, so that the temperature of the X-ray focal point 216 can be kept lower than the melting point of the target, and the anode 212 is overheated and melted. Can be prevented. The generated heat amount needs to be quickly discharged outside the pipe. However, when the heat input amount is large, the temporarily generated heat amount needs to be accumulated in the pipe. Therefore, in many X-ray tubes, the volume of the anode 212 is increased in order to increase the amount of stored heat, and accordingly the X-ray tube 210 is also increased in size.

  The container 220 in which the X-ray tube 210 is stored is filled with cooling water as a cooling medium or insulating oil as a cooling medium while electrically insulating the X-ray tube 210. The cooling water or insulating oil filled in the container 220 is guided to the cooler 302 through the pipe 301 connected to the container 220 of the X-ray tube apparatus 101, and after the heat is dissipated in the cooler 302, the pipe 301 Returned into container 220.

  The average temperature of the anode 212 is about 1000 ° C. due to the heat generated at the X-ray focal point 216. About 90% of the generated heat is radiated from the surface of the anode 212 to the envelope 213 by radiation, and the remaining 10% of the heat flows to the envelope 213 through the rotating device 214 by heat conduction. Since the heat flowing to the rotating device 214 causes various harmful effects, it is necessary to devise a method for transferring heat.

  Hereinafter, the structure of the rotating device 214, particularly the structure of the rotor 214B, will be described in detail including the relationship with the surroundings.

(First embodiment)
FIG. 3 shows a cross-sectional view of the rotor 214B of the first embodiment and its peripheral portion. In the present embodiment, the anode 212 has an annular shape, and an outer cylindrical portion 214B-1 and an inner cylindrical portion 214B-2 are provided on the back side of the surface facing the cathode. The outer cylindrical portion 214B-1 and the inner cylindrical portion 214B-2 are concentric cylinders that share the tube axis 219, that is, a double-structure cylinder.

  The inner cylindrical portion 214B-2 is connected to the rotation shaft 214B-4. The rotating shaft 214B-4 is rotatably supported by a bearing 214D. The bearing 214D is held by the stator 214C. The stator 214C is supported by the envelope 213 on the cathode 211 side through the hole of the annular anode 212. In FIG. 3, in order to distinguish the rotating part and the non-rotating part, the non-rotating part, that is, the stator 214C and the envelope 213 are indicated by hatching. Except for the hatched portion, the tube shaft 219 is rotated as a rotation axis.

  A lubrication layer is formed between the bearing 214D and the rotating shaft 214B-4 by applying or forming a lubricant to prevent damage to them and to reduce friction and wear. As the lubricant, lead, silver, gold, an alloy thereof, molybdenum disulfide, graphite, or the like is used so that it can withstand rotation in a vacuum at a high temperature. When the X-ray tube 210 is manufactured, the lubrication layer is formed with a uniform thickness. However, if the rotary shaft 214B-4 and the bearing 214D are overheated, the lubrication layer becomes non-uniform in thickness and rotates with the bearing 214D. Friction between the shafts 214B-4 increases and rotation failure occurs. In order to prevent overheating of the rotating shaft 214B-4 and the bearing 214D, the amount of heat flowing to the rotating shaft 214B-4 and the bearing 214D may be reduced. Since the anode 212 rotates about the tube axis 219 as a rotation axis, a ring formed by rotating the X-ray focal point 216 around the tube axis 219 becomes a heat generation location.

  Therefore, in this embodiment, the outer cylindrical portion 214B-1 is provided outside the inner cylindrical portion 214B-2 in order to suppress the heat generated by the collision of the electron beam 215 from flowing to the rotating shaft 214B-4 and the bearing 214D. ing. The outer cylindrical portion 214B-1 has a length up to the vicinity of the envelope 213 in the direction of the tube axis 219. Since the outer cylindrical portion 214B-1 has such a length, the outer cylindrical portion 214B-1 has a surface facing the envelope 213, and the outer cylindrical portion 214B-1 and the envelope 213 overlap each other. It becomes. Since the envelope 213 is cooled by the cooling medium filled in the container 220, the heat conducted through the outer cylindrical portion 214B-1 is radiated from the surface of the outer cylindrical portion 214B-1 facing the outer envelope 213. To efficiently dissipate heat.

  In order to further efficiently dissipate heat from the surface of the outer cylindrical portion 214B-1, it is desirable that the envelope 213 protrudes inside the outer cylindrical portion 214B-1. By adopting such a shape, the area of the surface where the envelope 213 cooled by the cooling medium and the outer cylindrical portion 214B-1 face each other increases, so that heat is radiated from the surface of the outer cylindrical portion 214B-1. Is done more efficiently. Further, the blackening film 214B-3 may be formed on the surface of the outer cylindrical portion 214B-1 facing the envelope 213. By forming the blackening film 214B-3, the heat radiation from the surface of the outer cylindrical portion 214B-1 can be further improved. FIG. 3 shows an example in which the blackening film 214B-3 is formed on the outer surface and the inner surface of the outer cylindrical portion 214B-1, but the blackening film 214B-3 is formed on one of the surfaces. You can just do it. The same effect can be obtained by forming irregularities instead of forming the blackening film 214B-3.

  Further, in order to suppress heat transfer to the inner cylindrical portion 214B-2 and promote heat transfer to the outer cylindrical portion 214B-1, the thickness of the outer cylindrical portion 214B-1 is set to the thickness of the inner cylindrical portion 214B-2. It is preferable to make it thicker. Furthermore, it is preferable to select both materials so that the thermal conductivity of the outer cylindrical portion 214B-1 is higher than the thermal conductivity of the inner cylindrical portion 214B-2. For example, copper is used for the outer cylindrical portion 214B-1, and stainless steel is used for the inner cylindrical portion 214B-2. Since copper has a melting point of about 1080 ° C., a high-melting point material such as molybdenum is used on the side connected to the anode 212 of the outer cylindrical portion 214B-1, and a portion near the envelope 213 is made of copper. May be used. Further, in order to suppress heat transfer to the inner cylindrical portion 214B-2, the thickness of the anode 212 where the inner cylindrical portion 214B-2 is connected is thinner than the portion where the outer cylindrical portion 214B-1 is connected. It is preferable to keep it.

  By configuring as described above, heat transfer to the inner cylindrical portion 214B-2 connected to the rotating shaft 214B-4 is suppressed, and the amount of heat flowing to the rotating shaft 214B-4 and the bearing 214D can be reduced. It is possible to prevent a rotation failure caused by overheating of the rotating shaft 214B-4 and the bearing 214D.

  In order to further efficiently dissipate heat from the surface of the outer cylindrical portion 214B-1, the cooling efficiency of the surface of the envelope 213 protruding inside the outer cylindrical portion 214B-1 may be improved. An example of such a structure will be described with reference to FIG. FIG. 4 is an enlarged view of the end of the envelope 213 on the anode 212 side. Inside the protruding portion of the envelope 213 shown in FIG. 4, a flow path forming cylinder 400 for forming a flow path for the cooling medium is provided. The flow path forming cylinder 400 is supported by a container 220 not shown in FIG. By providing the flow path forming cylinder 400, the cooling medium forms a flow path in the direction of the arrow in FIG. When the flow path is formed in this way, the cooling medium cooled by the cooler 302 is guided to the surface of the envelope 213 protruding inside the outer cylindrical portion 214B-1, so that the outer cylindrical portion 214B-1 The heat dissipation from the surface is further improved.

  The inventor verified the effect of this structure by the following temperature analysis. In this analysis, in the X-ray tube having the configuration shown in FIG. 3, the outer diameter of the anode 212 is 200 mm, the inner cylindrical portion has an inner diameter of 60 mm, the outer diameter is 62 mm, the length is 65 mm, the outer cylindrical portion has an inner diameter of 72 mm, The outer diameter was 80 mm, the length was 120 mm, and the temperature change of the bearing with or without the outer cylindrical part was examined. Assuming that the outer cylindrical portion was made of molybdenum up to 60 mm from the anode 212 side, copper of the tip of 60 mm was made of copper, and a blackened film was coated on the outer surface of copper, the emissivity was set to 0.8. Further, heat input conditions were set such that the average temperature of the anode 212 was 1000 ° C. As a result, it was confirmed that the bearing temperature was about 500 ° C. when there was no outer cylindrical portion, but could be reduced to 410 ° C. when there was an outer cylindrical portion.

(Second embodiment)
FIG. 5 shows a sectional view of the rotor 214B of the second embodiment and its peripheral portion. A significant difference from the first embodiment is the length of the inner cylindrical portion 214B-2. Each configuration will be described below. In addition, about the same structure as 1st embodiment, it is the same code | symbol and abbreviate | omits description.

  In the present embodiment, the length of the inner cylindrical portion 214B-2 is substantially equal to the length of the outer cylindrical portion 214B-1. By adopting such a structure, the inner cylindrical portion 214B-2 is longer than in the first embodiment and the heat transfer distance is extended, so that heat transfer to the rotating shaft 214B-4 and the bearing 214D can be further suppressed. it can. As a result, it is effective in preventing rotation failure due to overheating of the rotating shaft 214B-4 and the bearing 214D.

  As the inner cylindrical portion 214B-2 is extended, the lengths of the rotating shaft 214B-4 and the stator 214C are increased, so that the rotation of the anode 212 becomes more stable.

  Since the projecting portion of the envelope 213 is not provided, when the blackened film 214B-3 is formed, it may be provided only on the outer surface of the outer cylindrical portion 214B-1.

(Third embodiment)
FIG. 6 shows a cross-sectional view of the rotor 214B of the third embodiment and the periphery thereof. The difference from the first embodiment is the position where the stator 214C is supported. Each configuration will be described below. In addition, about the same structure as 1st embodiment, it is the same code | symbol and abbreviate | omits description.

  In the present embodiment, the stator 214C is supported by the envelope 213 on the anode 212 side. By adopting such a structure, the stator 214C does not receive radiation from the anode 212 having an average temperature of about 1000 ° C., so that the amount of heat flowing to the bearing 214D and the rotating shaft 214B-4 can be reduced. As a result, it is effective in preventing rotation failure due to overheating of the rotating shaft 214B-4 and the bearing 214D.

  Although the annular anode 212 is illustrated in FIG. 6, the anode 212 may have a disk shape in the present embodiment.

(Fourth embodiment)
FIG. 7 shows a sectional view of the rotor 214B of the fourth embodiment and its peripheral portion. The difference from the first embodiment is the position where the stator 214C is supported and the shape of the rotating shaft 214B-4. Each configuration will be described below. In addition, about the same structure as 1st embodiment, it is the same code | symbol and abbreviate | omits description.

  In this embodiment, two stators 214C are provided, and one stator 214C is supported by the envelope 213 on the cathode 211 side through the hole of the annular anode 212, and the other is supported by the envelope 213 on the anode 212 side. Supported. Further, the rotating shaft 214B-4 of the present embodiment has a shape in which the portion supported by the bearing 214D extends from the portion joined to the inner cylindrical portion 214B-2 along both the tube axis 219 in both the cathode side and the anode side. It has become. By adopting such a structure, even when the amount of heat conducted to the inner cylindrical portion 214B-2 becomes large, the amount of heat transfer is dispersed on the cathode side and the anode side, so that the overheating of the rotating shaft 214B-4 and the bearing 214D This is effective in preventing rotation failure.

  Further, since the rotating shaft 214B-4 is supported by both the cathode side stator 214C and the anode side stator 214C, the rotation of the anode 212 becomes more stable.

  In addition, you may implement combining the some component disclosed by embodiment suitably. For example, in the structure of the third embodiment or the fourth embodiment, the envelope 213 on the anode 212 side may have a shape protruding inside the outer cylindrical portion 214B-1. When the envelope 213 on the anode 212 side is protruded, the blackening film 214B-3 may be formed on the inner surface of the outer cylindrical portion 214B-1.

  1 X-ray CT device, 100 scan gantry unit, 101 X-ray tube device, 102 rotating disk, 103 collimator, 104 opening, 105 bed, 106 X-ray detector, 107 data collection device, 108 gantry control device, 109 bed control Device, 110 X-ray control device, 120 console, 121 input device, 122 image processing device, 123 storage device, 124 system control device, 125 display device, 210 X-ray tube, 211 cathode, 212 anode, 213 envelope, 214 Rotating device, 214A excitation coil, 214B rotor, 214B-1 outer cylindrical part, 214B-2 inner cylindrical part, 214B-3 blackening film, 214B-4 rotating shaft, 214C stator, 214D bearing, 215 electron beam, 216 focus , 217 X-ray, 218 Radiation window, 219 tube axis, 220 container, 301 piping, 302 cooler, 400 flow path forming cylinder

Claims (9)

A cathode that generates an electron beam; an anode that is disposed opposite to the cathode and emits X-rays when irradiated with the electron beam; an envelope that holds the cathode and the anode in a vacuum atmosphere; and the anode An X-ray tube device having an anode rotation drive unit for rotating
The anode has a double-structured cylindrical portion on the back side of the surface facing the cathode,
The inner cylindrical part of the cylindrical part is connected to a rotary bearing,
The X-ray tube apparatus according to claim 1, wherein an outer cylindrical portion of the cylindrical portion has a length reaching the vicinity of the envelope. In the X-ray tube device according to claim 1,
The anode has a ring shape;
The X-ray tube apparatus according to claim 1, wherein a bearing fixing portion that supports the bearing is disposed on a surface side facing the cathode through an annular hole of the anode. In the X-ray tube device according to claim 1,
The X-ray tube apparatus according to claim 1, wherein the envelope has a protruding portion protruding inside the outer cylindrical portion. In the X-ray tube device according to claim 3,
The periphery of the envelope is filled with a cooling fluid, and further includes a flow path that introduces the cooling fluid into the surface of the protrusion and guides the cooling fluid from the center of the protrusion. X-ray tube device. In the X-ray tube device according to claim 1,
The X-ray tube apparatus according to claim 1, wherein a thickness of the outer cylindrical portion is thicker than a thickness of the inner cylindrical portion. In the X-ray tube device according to claim 1,
The X-ray tube apparatus according to claim 1, wherein a thickness of a portion where the inner cylindrical portion is connected to the anode is thinner than a thickness where the outer cylindrical portion is connected. In the X-ray tube device according to claim 1,
The X-ray tube apparatus according to claim 1, wherein a thermal conductivity of the outer cylindrical portion is higher than a thermal conductivity of the inner cylindrical portion. In the X-ray tube device according to claim 1,
The X-ray tube apparatus according to claim 1, wherein the outer cylindrical portion has irregularities or a blackening film on a surface facing the envelope. Equipped with an X-ray source that irradiates the subject with X-rays, an X-ray detector that is disposed opposite to the X-ray source and detects X-rays transmitted through the subject, and the X-ray source and the X-ray detector A rotating disk that rotates around the subject, an image reconstruction device that reconstructs a tomographic image of the subject based on a transmitted X-ray amount detected by the X-ray detector, and a reconstruction performed by the image reconstruction device An X-ray CT apparatus provided with an image display device for displaying a tomographic image,
2. The X-ray CT apparatus according to claim 1, wherein the X-ray source is the X-ray tube apparatus according to claim 1.

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