JP2010257900A - Rotary anode type x-ray tube assembly - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary anode type X-ray tube assembly capable of preventing damage of a housing. <P>SOLUTION: The rotary anode type X-ray tube assembly is provided with an X-ray tube 30 having a negative electrode 36, a positive electrode target 35a, a vacuum outer envelope 31 made of glass, a rotary body 2, and a fixed body 1, a stator coil 910 for rotating the rotary body, a housing 20, a protective body 70 and a cooling liquid 7. The protective body 70 has an X-ray transmitting window 71 which is fixed at least either on the vacuum outer envelope 31 and the housing 20 and is positioned between the vacuum outer envelope 31 and the housing 20 and is arranged separated from the vacuum outer envelope 31 and from the housing 20, and transmits X-ray. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a rotary anode type X-ray tube apparatus.

  In general, a rotary anode X-ray tube apparatus is used for X-ray imaging (for example, X-ray imaging or CT imaging) performed in the medical field or the like. The rotary anode X-ray tube device includes a housing made of a brittle material such as an aluminum casting, and an X-ray tube that is accommodated in the housing and emits X-rays. A lead plate for shielding X-rays is attached to the inner surface of the housing. The wall surface of the housing is provided with a radiation window formed so as to be able to emit X-rays emitted from the X-ray tube.

  A cooling liquid such as insulating oil is sealed in the housing. The X-ray tube has a vacuum envelope. In the vacuum envelope, an anode target capable of high-speed rotation (for example, 10,000 RPM) and a cathode disposed to face the anode target are provided. The anode target is formed in a disk shape from a tungsten alloy. Due to the high voltage applied between the cathode and the anode target, electrons emitted from the cathode collide with the target layer of the anode target, and X-rays are emitted from the target layer.

  In the rotating anode X-ray tube apparatus, if the anode target is broken during high-speed rotation, the anode target may be scattered with high kinetic energy. When the anode target is scattered, the vacuum envelope is broken by the fragments of the anode target. Furthermore, the anode target fragments may collide with the housing and cause damage to the housing. If the housing is damaged during X-ray imaging, there is a risk that a high-temperature coolant will be applied to the object to be inspected (for example, a human body).

  For this reason, as a technique for avoiding the above-described danger, a technique for attaching a protective body to the inner surface of the housing is disclosed (for example, refer to Patent Documents 1 and 2). The protector protects the anode target debris from colliding with the housing.

US Patent No. 70000662 JP 2008-84597 A

  In the said patent document 1, a protection body is a cylinder which consists of a raw material used for a bulletproof vest. In Patent Document 2, the protective body is a cylinder made of a ductile material such as a stainless steel plate. When these protective bodies are used, when a fragment of the anode target collides with the protective body, the protective body can absorb a part of the kinetic energy of the anode target by causing deformation.

However, since the protective body is arranged in contact with the inner surface of the housing, deformation caused to the protective body is limited. As a result, the kinetic energy is not sufficiently absorbed by the protective body, and the remaining energy is transmitted to the housing itself, so that damage to the housing made of a brittle material such as an aluminum casting cannot be avoided.
The present invention has been made in view of the above points, and an object of the present invention is to provide a rotary anode X-ray tube apparatus capable of preventing the housing from being damaged.

In order to solve the above-described problem, a rotary anode X-ray tube apparatus according to an aspect of the present invention includes:
A cathode that emits electrons; an anode target that emits X-rays when electrons emitted from the cathode collide; a vacuum envelope made of glass and containing at least the cathode and the anode target; and the anode An X-ray tube having a rotating body fixed to the target and rotatably provided together with the anode target; and a fixing body that rotatably supports the rotating body;
A rotation driving device for rotating the rotating body;
A housing containing at least the vacuum envelope;
X-ray transmission that is fixed to at least one of the vacuum envelope and the housing, is located between the vacuum envelope and the housing, is provided with a gap between the vacuum envelope and the housing, and transmits the X-ray. A protective body having a window and capable of absorbing the kinetic energy of the fragments of the anode target;
A cooling liquid filling the space between the X-ray tube and the housing including the space between the vacuum envelope and the protective body and between the protective body and the housing.

  According to the present invention, it is possible to provide a rotary anode type X-ray tube apparatus capable of preventing the housing from being damaged.

It is sectional drawing which shows the rotating anode type | mold X-ray tube apparatus which concerns on embodiment of this invention. It is sectional drawing which shows the modification of the said rotating anode type X-ray tube apparatus. It is sectional drawing which shows the other modification of the said rotating anode type X-ray tube apparatus.

  Hereinafter, a rotary anode X-ray tube apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing a rotary anode type X-ray tube apparatus 10 according to an embodiment of the present invention.

  As shown in FIG. 1, the X-ray tube apparatus 10 includes a cylindrical housing 20 closed at both ends, an X-ray tube 30 housed in the housing 20, and the housing 20 is filled with an X-ray tube 30. And a coolant 7 filling the space between the housings 20 and a stator coil 910 as a rotational drive device. The housing 20 has a radiation window 24 that emits X-rays to the outside of the housing 20. In this embodiment, no lead plate is attached to the inner surface of the housing 20. The inner surface of the housing 20 is in contact with the coolant 7.

  The X-ray tube 30 includes a vacuum envelope 31. The vacuum envelope 31 includes a glass container 32 made of glass, a high voltage insulating member 50, and the like. An anode 35 is indirectly attached to the glass container 32, and a cathode 36 is indirectly attached to the high voltage insulating member 50. The cathode 36 emits electrons for irradiating the anode 35. The anode 35 and the cathode 36 are accommodated in a vacuum envelope 31.

  The anode 35 has an anode target 35a and a support 35c. The anode target 35a is formed in a disc shape. The anode target 35a has a target layer 35b provided on a part of the outer surface of the anode target. The target layer 35b emits X-rays when electrons emitted from the cathode 36 collide. The support 35c supports the anode target 35a. The support 35c is formed integrally with the anode target 35a. The anode 35 is made of a metal such as a tungsten alloy. The anode 35 can rotate around the tube axis. A relatively positive voltage is applied to the anode 35.

  A voltage supply terminal 54 is connected to the cathode 36. The voltage supply terminal 54 applies a relatively negative voltage to the cathode 36 and supplies a filament current to a filament (not shown) of the cathode 36.

  The X-ray tube 30 includes a rotor 920, a bearing 930, a fixed body 1, and a rotating body 2. The fixed body 1 is formed in a cylindrical shape, and is fixed to the glass container 32 and the high voltage insulating member 6. The fixed body 1 supports the rotating body 2 in a rotatable manner. The rotating body 2 is formed in a cylindrical shape and is provided coaxially with the fixed body 1. A rotor 920 is attached to the outer surface of the rotating body 2. A support 35 c is fixed to the rotating body 2. The rotating body 2 is rotatably provided with the anode 35.

  A part of the fixed body 1 forms a part of the vacuum envelope 31. The tip of the fixed body 1 at a location passing through the high voltage insulating member 6 functions as a voltage supply terminal. A high voltage is supplied to the anode 35 through the tip of the fixed body 1.

  The high voltage insulating member 6 is formed in a tubular shape with one end having a conical shape and the other end closed. The high voltage insulating member 6 electrically insulates the fixed body 1 from the housing 20 and the stator coil 910.

  The high voltage insulating member 50 forms a part of the vacuum envelope 31. Inside the high voltage insulating member 50, there is provided a voltage supply terminal 54 connected to the cathode 36 and leading out to the outer end face side of the high voltage insulating member 50. In this embodiment, the voltage supply terminal 54 is a high voltage supply terminal. The voltage supply terminal 54 is provided through the high-voltage insulating member 50 and supplies a high voltage to the cathode 36. The voltage supply terminal 54 is supported by a KOV member 55 that is a low expansion alloy. Between the KOV member 55 and the cathode 36 and between the KOV member 55 and the high voltage insulating member 50 are brazed.

  The anode receptacle 100 has a bottomed cylindrical housing 101 and terminals 102. The housing 101 is airtightly attached to the housing 20. The housing 101 is made of, for example, resin as an insulating material. The terminal 102 is provided in the housing 101. The terminal 102 is electrically connected to the fixed body 1 by a cable.

  The receptacle 100 and a plug (not shown) are detachable. In a state where the plug is connected to the receptacle 100, the receptacle 100 supplies a high voltage (for example, +70 to +80 kV) to the fixed body 1.

  The cathode receptacle 200 has a bottomed cylindrical housing 201 and terminals 202. The housing 201 is airtightly attached to the housing 20. The housing 201 is formed of, for example, a resin as an insulating material. The terminal 202 is provided in the housing 201. The terminal 202 is electrically connected to the voltage supply terminal 54 by a cable.

  The receptacle 200 and other plugs (not shown) are detachable. In a state where the plug is connected to the receptacle 200, the receptacle 200 supplies a high voltage (for example, −70 to −80 kV) and a filament current to the voltage supply terminal 54.

  An air basin 5 is provided on one end side of the housing 20 facing the target layer 35b. The air basin 5 includes a bellows 21 and a lid portion 22 that is located at one end interval of the housing 20. The lid 22 is airtightly attached to the housing 20 in a direction perpendicular to the rotation axis of the anode 35. The lid 22 has an opening 22a through which the coolant 7 enters and exits. A vent hole 20a through which air as an atmosphere enters and exits is formed at one end of the housing 20.

  The bellows 21 divides a region surrounded by the housing 20 and the lid portion 22 into a first region connected to the opening 22a and a second region connected to the vent hole 20a. The bellows 21 is formed to be deformed. Since the bellows 21 can change the width of the first region and the second region, the air basin 5 can absorb the expansion and contraction of the coolant 7.

  In addition, an X-ray shielding part 90 is provided on one end side of the housing 20 facing the target layer 35b. The X-ray shielding unit 90 shields X-rays emitted from the target layer 35b. The X-ray shielding part 90 is formed of a material containing an X-ray opaque material. The X-ray shielding unit 90 includes a first shielding unit 91, a second shielding unit 92, and a third shielding unit 93.

  The first shielding part 91 is formed in a disk shape and is attached to the lid part 22. The first shielding portion 91 covers the entire lid portion 22. The first shielding portion 91 is formed by opening a portion facing the opening 22a, and keeps the coolant 7 in and out of the opening 22a.

  The second shielding part 92 is formed in a cylindrical shape. The second shielding part 92 is formed on the first shielding part 91. The third shielding part 93 is provided on the first shielding part 91. The third shielding part 93 shields X-rays that may be emitted from the vicinity of the opening 22a.

  The protective body 70 is fixed to at least one of the vacuum envelope 31 and the housing 20. Here, the protective body 70 is fixed to the housing 20 and indirectly fixed to the vacuum envelope 31. The protective body 70 is provided with a gap between the glass container 32 and the housing 20. The protective body 70 is located between the glass container 32 and the housing 20. The protective body 70 is located at least facing the anode target 35a in the direction perpendicular to the rotation axis of the anode target 35a.

  The protective body 70 is formed in a cylindrical shape made of a ductile material such as a stainless steel plate. The protective body 70 has an X-ray transmission window 71 that transmits X-rays. The X-ray transmission window 71 faces the radiation window 24. Here, the X-ray transmission window 71 is an opening in which a part of the protective body 70 is opened.

  The protective body 70 protects the collision of the fragments of the anode target 35a, which is scattered in a state having high kinetic energy, with the housing 20 when the anode target 35a is broken during high-speed rotation.

  Even if a fragment of the anode target 35a collides with the protective body 70, the protective body 70 can absorb kinetic energy by causing sufficient deformation. Since the protective body 70 and the housing 20 are positioned with a gap therebetween, the deformation of the housing 20 itself can be prevented even if the protective body 70 is deformed. Thereby, the crack which may arise in the housing 20 can be prevented.

  The X-ray shield 80 is fixed to at least one of the vacuum envelope 31 and the housing 20. Here, the X-ray shield 80 is fixed to the housing 20 and indirectly fixed to the vacuum envelope 31. The X-ray shield 80 is located between the glass container 32 and the housing 20. The X-ray shield 80 is provided with a gap between the glass container 32 and the housing 20.

  The X-ray shield 80 is made of a material containing an X-ray opaque material. The radiopaque material is a metal composed of at least one of tungsten, tantalum, molybdenum, barium, bismuth, rare earth metal and lead, or a compound of tungsten, tantalum, molybdenum, barium, bismuth, rare earth metal and lead. At least one is contained as a main material.

  The X-ray shield 80 is formed in a cylindrical shape. In this embodiment, the X-ray shield 80 is formed of a lead cylinder. The surface of the lead cylinder is formed with metal plating or resin coating of tin, silver, copper, nickel or the like for protection against corrosion.

  In this embodiment, the protective body 70 and the X-ray shield 80 are integrally formed. The X-ray shield 80 is located between the protective body 70 and the housing 20. The X-ray shield 80 is formed by attaching a lead plate to the outer surface of the protective body 70.

The X-ray shield 80 has an X-ray transmission window 81 that transmits X-rays. The X-ray transmission window 81 faces the radiation window 24 and the X-ray transmission window 71. Here, the X-ray transmission window 81 is an opening in which a part of the X-ray shield 80 is opened.
The X-ray shield 80 shields X-rays emitted in directions other than the X-ray transmission window 81. One end of the X-ray shield 80 is close to the first shield 91 and the second shield 92. For this reason, X-rays that may be emitted from the gap between the X-ray shield 80 and the X-ray shield 90 can be shielded.

  The protective body 70 and the X-ray shield 80 have an opening through which the receptacle 200 passes. The X-ray shield 80 has a cylindrical portion 82 that surrounds the outer periphery of the receptacle 200. The cylindrical portion 82 can shield X-rays that may pass through the receptacle 200 and exit to the outside.

  The thickness of the protective body 70 is 0.5 to 3 mm. In this embodiment, the thickness of the protective body 70 is 1 mm. The thickness of the X-ray shield 80 is 1 to 3 mm. In this embodiment, the thickness of the X-ray shield 80 is 2.5 mm. In the direction perpendicular to the rotation axis of the anode target 35a, the gap between the glass container 32 and the housing 20 is 3 to 12 mm. In this embodiment, the gap between the glass container 32 and the housing 20 is 8 mm.

  The protective body 70 (X-ray shield 80) is fixed to the vacuum envelope 31 by the insulating member 8. The X-ray shield 80 (protective body 70) is fixed to the housing 20 by the insulating member 9.

The coolant 7 is filled in the housing 20 and fills the space between the X-ray tube 30 and the housing 20. The coolant 7 also fills a region including the space between the vacuum envelope 31 and the protective body 70 and the space between the X-ray shield 80 and the housing 20.
As the cooling liquid 7, insulating oil can be used.

  In the X-ray tube apparatus 10 configured as described above, when a predetermined current is applied to the stator coil 910, the rotor 920 rotates and the anode target 35a (anode 35) rotates. Next, a predetermined high voltage is applied to the receptacles 100 and 200.

  The high voltage applied to the receptacle 100 is supplied to the anode target 35 a of the anode 35 through the fixed body 1, the bearing 930 and the rotating body 2. The high voltage applied to the receptacle 200 is supplied to the cathode 36 via the voltage supply terminal 54.

  Thereby, an electron beam is emitted from the cathode 36 to the target layer 35b of the anode target 35a, and X-rays are emitted from the anode target 35a, and the X-rays pass through the glass container 32, the X-ray transmission windows 71 and 81, and the emission window 24. It is transmitted through and radiated to the outside.

  According to the rotary anode X-ray tube apparatus configured as described above, the rotary anode X-ray tube apparatus includes the cathode 36, the anode target 35a, the vacuum envelope 31, the rotary body 2, and the fixed body. 1, the stator coil 910, the housing 20, the protective body 70, and the coolant 7 filling the space between the X-ray tube 30 and the housing 20.

  The protective body 70 is fixed to at least one of the vacuum envelope 31 and the housing 20. The protector 70 is provided with a gap between the vacuum envelope 31 and the housing 20. The protective body 70 is located between the vacuum envelope 31 and the housing 20.

  The protective body 70 protects the collision of the fragments of the anode target 35a, which is scattered in a state having high kinetic energy, with the housing 20 when the anode target 35a is broken during high-speed rotation. Even if a fragment of the anode target 35a collides with the protective body 70, the protective body 70 can absorb kinetic energy by causing sufficient deformation.

  Thereby, the crack which may arise in the housing 20 can be prevented. For example, when a rotating anode type X-ray tube device is mounted on a medical diagnostic instrument, the risk that the high-temperature coolant 7 may be applied to an object to be inspected (for example, a human body) can be eliminated.

  The X-ray shield 80 is made of a material containing an X-ray opaque material. Since the X-ray shield 80 can shield X-rays in directions other than the X-ray transmission window 81, for example, when the X-ray tube device is mounted on a medical diagnostic device, unnecessary radiation (exposure to the human body) ) Can be prevented.

The X-ray shield 80 is fixed to at least one of the vacuum envelope 31 and the housing 20. The X-ray shield 80 is provided with a gap between the vacuum envelope 31 and the housing 20. The X-ray shield 80 is located between the vacuum envelope 31 and the housing 20. Here, the X-ray shield 80 is formed by attaching a lead plate to the outer surface of the protective body 70. The X-ray shield 80 is fixed to the housing 20 together with the protective body 70.
Since it is not necessary to attach a lead plate to the inner surface of the housing 20 or replace the lead plate with an X-ray shielding material instead of lead, the manufacturing cost can be reduced.

  From the above, it is possible to obtain a rotary anode X-ray tube device that can prevent the housing 20 from being damaged. Furthermore, a rotating anode type X-ray tube apparatus that can reduce the manufacturing cost can be obtained.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiments. For example, some components may be deleted from all the components shown in the embodiment.

  As shown in FIG. 2, the protective body 70 may be formed of a material containing a solid resin material as a main component and containing an X-ray opaque material. The protective body 70 has a cylindrical portion 72 that surrounds the outer periphery of the receptacle 200. In this case, the X-ray tube device can be formed without the X-ray shield 80.

  The X-ray opaque material includes at least metal fine particles made of any one of tungsten, tantalum, molybdenum, barium, bismuth, rare earth metal and lead, or tungsten, tantalum, molybdenum, barium, bismuth, rare earth metal and lead. It is sufficient if at least one of the compound fine particles is contained as a main material.

  Solid resin material is at least thermosetting epoxy resin, unsaturated polyester resin, phenol resin, diallyl phthalate resin, thermoplastic epoxy resin, nylon resin, aromatic nylon resin, polybutylene terephthalate resin, polyethylene terephthalate resin, polyphenylene sulfide resin Any one of polyphenylene ether resin, liquid crystal polymer, and methylpentene polymer resin may be included.

  In this case, the X-ray shielding part 90 may be formed of the same material as the protective body 70. The protective body 70 mainly composed of a solid resin material is more preferable because it contains reinforcing fibers together with the radiopaque material because the strength increases. As the reinforcing fiber, glass fiber, carbon fiber, boron fiber, alumina fiber, aramid fiber, or the like can be selected.

  As shown in FIG. 3, the X-ray shield 80 may be provided on the inner surface of the housing 20. Here, the X-ray shield 80 is formed by sticking an X-ray shielding member such as lead on the inner surface of the housing 20.

  The protective body 70 only needs to be formed of a material that can absorb the kinetic energy of the fragments of the anode target, and it is only necessary to prevent cracks that may have occurred in the housing 20. The protective body 70 is not limited to stainless steel, but may be formed of metal, resin, ceramics, or the like. Since the protective body 70 is best insulated from the high voltage potential, it is preferable to form the protective body 70 from an insulating material such as resin or ceramics.

  The protective body 70 mainly composed of a solid resin material is more preferable because it includes reinforcing fibers because the strength increases. As the reinforcing fiber, glass fiber, carbon fiber, boron fiber, alumina fiber, aramid fiber, or the like can be selected.

When the anode 35 is formed of molybdenum or a molybdenum alloy, the anode 35 can shield X-rays. In this case, it is not necessary to provide an X-ray shielding part on the other end side of the housing 20 where the receptacle 100 is located. When the anode 35 transmits X-rays, an X-ray shielding part may be provided also on the other end side of the housing 20.
The present invention can be applied not only to the rotary anode X-ray tube apparatus but also to various rotary anode X-ray tube apparatuses.

  DESCRIPTION OF SYMBOLS 1 ... Fixed body, 2 ... Rotating body, 7 ... Coolant, 10 ... X-ray tube apparatus, 20 ... Housing, 30 ... X-ray tube, 31 ... Vacuum envelope, 32 ... Glass container, 35 ... Anode, 35a ... Anode target, 35b ... target layer, 35c ... support, 36 ... cathode, 70 ... protector, 71 ... X-ray transmission window, 80 ... X-ray shield, 81 ... X-ray transmission window, 910 ... stator coil.

Claims (8)

A cathode that emits electrons; an anode target that emits X-rays when electrons emitted from the cathode collide; a vacuum envelope made of glass and containing at least the cathode and the anode target; and the anode An X-ray tube having a rotating body fixed to the target and rotatably provided together with the anode target; and a fixing body that rotatably supports the rotating body;
A rotation driving device for rotating the rotating body;
A housing containing at least the vacuum envelope;
X-ray transmission that is fixed to at least one of the vacuum envelope and the housing, is located between the vacuum envelope and the housing, is provided with a gap between the vacuum envelope and the housing, and transmits the X-ray. A protective body having a window and capable of absorbing the kinetic energy of the fragments of the anode target;
A rotary anode type X-ray tube device comprising: a cooling liquid that fills between the X-ray tube and the housing including between the vacuum envelope and the protective body, and between the protective body and the housing.   2. The rotary anode X-ray tube apparatus according to claim 1, wherein the protective body is positioned to face the anode target in a direction perpendicular to a rotation axis of the anode target.   The rotary anode X-ray tube device according to claim 1, wherein the protective body is formed of a ductile material.   The rotary anode X-ray tube apparatus according to claim 1, wherein the protective body is formed in a cylindrical shape.   The rotary anode type X-ray tube device according to any one of claims 1 to 4, wherein the protective body is formed of a material containing an X-ray opaque material.   6. The radiopaque material contains, as a main material, at least one of a metal composed of any one of tungsten, tantalum, molybdenum, barium, bismuth, rare earth metal and lead, or a compound thereof. Rotating anode type X-ray tube device described in 1.   The rotary anode type X-ray tube apparatus according to claim 1, wherein the protective body is formed of a material mainly composed of a solid resin material.   The solid resin material is thermosetting epoxy resin, unsaturated polyester resin, phenol resin, diallyl phthalate resin, thermoplastic epoxy resin, nylon resin, aromatic nylon resin, polybutylene terephthalate resin, polyethylene terephthalate resin, polyphenylene sulfide resin. The rotary anode X-ray tube device according to claim 7, comprising any one of a polyphenylene ether resin, a liquid crystal polymer, and a methylpentene polymer resin.

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