JPH0574959B2 - - Google Patents
Info
- Publication number
- JPH0574959B2 JPH0574959B2 JP60015295A JP1529585A JPH0574959B2 JP H0574959 B2 JPH0574959 B2 JP H0574959B2 JP 60015295 A JP60015295 A JP 60015295A JP 1529585 A JP1529585 A JP 1529585A JP H0574959 B2 JPH0574959 B2 JP H0574959B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- vacuum container
- examination room
- superconducting coil
- magnetic shield
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 230000005291 magnetic effect Effects 0.000 claims description 45
- 239000000696 magnetic material Substances 0.000 claims description 10
- 230000004907 flux Effects 0.000 claims description 4
- 230000035699 permeability Effects 0.000 claims description 4
- 239000003302 ferromagnetic material Substances 0.000 claims description 3
- 239000000463 material Substances 0.000 description 5
- 229910000976 Electrical steel Inorganic materials 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 102100040287 GTP cyclohydrolase 1 feedback regulatory protein Human genes 0.000 description 1
- 101710185324 GTP cyclohydrolase 1 feedback regulatory protein Proteins 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000000747 cardiac effect Effects 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000003325 tomography Methods 0.000 description 1
Landscapes
- Details Of Measuring And Other Instruments (AREA)
- Magnetic Resonance Imaging Apparatus (AREA)
- Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
Description
【発明の詳細な説明】
〔発明の技術分野〕
本発明は、磁気共鳴断層撮影装置（MRI装置）
の置かれた検査室の外に有害な磁界が漏れないよ
うにする磁気シールドに関するものである。[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a magnetic resonance tomography apparatus (MRI apparatus).
This relates to magnetic shielding that prevents harmful magnetic fields from leaking outside the examination room where the test room is located.
心臓のペースメーカ等の電子機器は10ガウス
（＝10-3テスラ）を超える磁場内で誤動作する場
合があり、MRI装置のように50cm球の内部に0.5
〜1.5テスラの磁場を発生する超電導コイルを一
般の病院内に設置する場合には超電導コイルの設
置される検査室内に磁気シールド体を配置し、一
般通路への漏れ磁界を10ガウス以下の安全な値ま
で下げる必要がある。超電導コイルを用いたマグ
ネツトの外側に磁性体を取り付けることにより磁
気シールドを行う場合にはマグネツトの重量が増
大し、建物の床面荷重が経済的に成り立たなくな
るほど大きくなつてしまう。建物の許容床面荷重
を越える場合には、床面強度を上げるために基礎
の改造を行うことになる。
Electronic devices such as cardiac pacemakers may malfunction in magnetic fields exceeding 10 Gauss (=10 -3 Tesla), and 0.5 mm inside a 50 cm sphere like an MRI machine.
When installing a superconducting coil that generates a magnetic field of ~1.5 Tesla in a general hospital, a magnetic shield is placed in the examination room where the superconducting coil is installed, and the leakage magnetic field to the general passageway is reduced to a safe level of 10 Gauss or less. need to be brought down to a value. When magnetic shielding is achieved by attaching a magnetic material to the outside of a magnet using a superconducting coil, the weight of the magnet increases and the floor load of the building becomes so large that it becomes uneconomical. If the allowable floor load of the building is exceeded, the foundation will need to be modified to increase the strength of the floor.
既設の建物ではこのような基礎の改造は不可能
なことが多く、MRI装置の磁気シールド対策を
十分に行うことが困難なことがあつた。 It is often impossible to modify the foundations of existing buildings in this way, and it has sometimes been difficult to take adequate magnetic shielding measures for MRI equipment.
本発明は、建屋の床荷重と磁気シールド室の専
有体積の条件下で最適の磁気シールド効果を達成
し、MRIの検査室の外に存在する静磁場の影響
を受ける器具装置を磁気的に保護する磁気シール
ドを提供することを目的とする。
The present invention achieves an optimal magnetic shielding effect under the conditions of the floor load of the building and the exclusive volume of the magnetically shielded room, and magnetically protects the instrumentation affected by the static magnetic field existing outside the MRI examination room. The purpose is to provide a magnetic shield that
上記目的を達成するために本発明は、円筒状の
超電導コイルを収容する２重筒状の真空容器を有
し、検査室内に設置されるMRI装置において、
前記真空容器の内筒を非磁性体で構成し、前記真
空容器の外筒と端板を飽和磁束密度の高い強磁性
体で構成し、前記検査室の壁に透磁性の高い磁性
体を配置した構成とする。
In order to achieve the above object, the present invention provides an MRI apparatus that has a double cylindrical vacuum container housing a cylindrical superconducting coil and is installed in an examination room.
The inner cylinder of the vacuum container is made of a non-magnetic material, the outer cylinder and end plate of the vacuum container are made of a ferromagnetic material with high saturation magnetic flux density, and a magnetic material with high magnetic permeability is arranged on the wall of the examination room. The configuration is as follows.
図面を用いて本発明の一実施例を説明する。 An embodiment of the present invention will be described using the drawings.
超電導コイル１をとりまいて、その内径側の非
磁性体よりなる内筒２と、外筒及び端板からなる
第一の磁気シールド体３を互いに気密に接合し、
配置する。内筒２と第１の磁気シールド体３は真
空容器４を構成する。 Surrounding the superconducting coil 1, an inner tube 2 made of a non-magnetic material on the inner diameter side and a first magnetic shield body 3 consisting of an outer tube and an end plate are hermetically joined to each other,
Deploy. The inner cylinder 2 and the first magnetic shield body 3 constitute a vacuum container 4 .
超電導コイル１は第一の磁気シールド体３に対
して熱伝導率の低い材料（例えばGFRP）を使つ
た支持棒で装着される。第一の磁気シールド体３
と内筒２で囲まれ、超電導コイル１を収容する空
間は10-4〜10-5Torr程度の真空にされた後密閉
され真空容器を形成する。 The superconducting coil 1 is attached to the first magnetic shield 3 using a support rod made of a material with low thermal conductivity (eg, GFRP). First magnetic shield body 3
The space surrounded by the inner cylinder 2 and accommodating the superconducting coil 1 is evacuated to about 10 -4 to 10 -5 Torr and then sealed to form a vacuum container.
第一の磁気シールド体３の材料は一般に電磁石
の磁芯として使われている飽和磁束密度の高い数
10mmの厚さの軟質磁性鋼板とする。 The material of the first magnetic shield 3 is a material with a high saturation magnetic flux density, which is generally used as the magnetic core of an electromagnet.
It shall be a soft magnetic steel plate with a thickness of 10 mm.
第二の磁気シールド体５は第一の磁気シールド
体３をとりまき、MRI装置の設置される検査室
の内壁に配置される。 The second magnetic shield 5 surrounds the first magnetic shield 3 and is placed on the inner wall of the examination room where the MRI apparatus is installed.
第二の磁気シールド体５を材料は透磁率の高い
磁性体例えばケイ素鋼板とする。 The second magnetic shield 5 is made of a magnetic material with high magnetic permeability, such as a silicon steel plate.
ケイ素鋼板は通常0.35〜0.70mmの厚さを有する
ので必要とする厚みを得るように積層して第二の
磁気シールド体５を形成する。 Since silicon steel plates usually have a thickness of 0.35 to 0.70 mm, the second magnetic shield body 5 is formed by laminating them to obtain the required thickness.
このような構成にすると真空容器と第一の磁気
シールド体とが兼用となるので、材料の量や製作
工数を低減することができる。 With such a configuration, the vacuum container and the first magnetic shielding body serve as both, so the amount of materials and the number of manufacturing steps can be reduced.
また、高磁場側におかれる第一の磁気シールド
体に飽和磁束密度の高い強磁性体を用い、低磁場
側におかれる第二の磁気シールド体に透磁率の高
い磁性体を配置して多層磁気シールドとしたの
で、すなわち、空間磁場の強さに応じて磁気特性
の異なる磁性体を組み合わせかつ磁気シールド体
を多層にしたのでもれ磁場を効果的に低減するこ
とができ、さらにMRI装置の重量による床面荷
重の分散をはかることができる。 In addition, a ferromagnetic material with high saturation magnetic flux density is used for the first magnetic shield placed on the high magnetic field side, and a magnetic material with high magnetic permeability is placed in the second magnetic shield placed on the low magnetic field side. By using a magnetic shield, in other words, by combining magnetic materials with different magnetic properties depending on the strength of the spatial magnetic field, and by making the magnetic shield material multi-layered, leakage magnetic fields can be effectively reduced. It is possible to distribute the floor load due to weight.
本発明のMRI装置においては超電導コイルを
収容する真空容器と検査室の壁で磁気シールドす
るので、装置全体の構成を簡単にすることがで
き、もれ磁場を効果的に低減して、重量やスペー
スを節約することができる。
In the MRI apparatus of the present invention, magnetic shielding is provided between the vacuum container housing the superconducting coil and the wall of the examination room, so the overall configuration of the apparatus can be simplified, leakage magnetic fields can be effectively reduced, and weight and weight can be reduced. It can save space.
図は本発明の一実施例のMRI装置を示す断面
図である。
１……超電導コイル、２……内筒、３……第１
の磁気シールド体、４……真空容器、５……第２
の磁気シールド体。
The figure is a sectional view showing an MRI apparatus according to an embodiment of the present invention. 1...Superconducting coil, 2...Inner cylinder, 3...First
magnetic shielding body, 4... vacuum container, 5... second
magnetic shield body.
Claims (1)
真空容器を有し、検査室内に設置されるMRI装
置において、前記真空容器の内筒を非磁性体で構
成し、前記真空容器の外筒と端板を飽和磁束密度
の高い強磁性体で構成し、前記検査室の壁に透磁
率の高い磁性体を配置したことを特徴とする
MRI装置。1. In an MRI apparatus that has a double cylindrical vacuum container that accommodates a cylindrical superconducting coil and is installed in an examination room, the inner cylinder of the vacuum container is made of a non-magnetic material, and the outer cylinder of the vacuum container is made of a non-magnetic material. and an end plate made of a ferromagnetic material with high saturation magnetic flux density, and a magnetic material with high magnetic permeability is arranged on the wall of the examination room.
MRI machine.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60015295A JPS61176199A (en) | 1985-01-31 | 1985-01-31 | Magnetic shield |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60015295A JPS61176199A (en) | 1985-01-31 | 1985-01-31 | Magnetic shield |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61176199A JPS61176199A (en) | 1986-08-07 |
| JPH0574959B2 true JPH0574959B2 (en) | 1993-10-19 |
Family
ID=11884839
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60015295A Granted JPS61176199A (en) | 1985-01-31 | 1985-01-31 | Magnetic shield |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61176199A (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4771256A (en) * | 1987-04-02 | 1988-09-13 | General Electric Company | Integral shield for mr magnet |
| JPS6429898U (en) * | 1987-08-12 | 1989-02-22 | ||
| JPH02276194A (en) * | 1987-09-01 | 1990-11-13 | Global Denshi Kenkyusho:Kk | Discharge lamp lighting device |
| JP2935235B2 (en) * | 1988-07-13 | 1999-08-16 | 株式会社東芝 | Current limiter |
| CN103472271B (en) * | 2012-06-08 | 2016-05-18 | 中国科学院空间科学与应用研究中心 | A kind of low-frequency band magnetic shielding cylinder |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55143100A (en) * | 1979-04-26 | 1980-11-08 | Tokyo Shibaura Electric Co | Magnetic shield device |
| JPS55165700A (en) * | 1979-06-12 | 1980-12-24 | Tohoku Metal Ind Ltd | Magnetic shielding room |
| JPS5615839U (en) * | 1979-07-16 | 1981-02-10 | ||
| JPS5616992B2 (en) * | 1974-11-29 | 1981-04-20 | ||
| JPS5814079A (en) * | 1981-07-17 | 1983-01-26 | Citizen Watch Co Ltd | Electronic clock with dot matrix display device |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6112720Y2 (en) * | 1979-07-17 | 1986-04-19 | ||
| JPS57150997U (en) * | 1981-03-18 | 1982-09-22 |
-
1985
- 1985-01-31 JP JP60015295A patent/JPS61176199A/en active Granted
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5616992B2 (en) * | 1974-11-29 | 1981-04-20 | ||
| JPS55143100A (en) * | 1979-04-26 | 1980-11-08 | Tokyo Shibaura Electric Co | Magnetic shield device |
| JPS55165700A (en) * | 1979-06-12 | 1980-12-24 | Tohoku Metal Ind Ltd | Magnetic shielding room |
| JPS5615839U (en) * | 1979-07-16 | 1981-02-10 | ||
| JPS5814079A (en) * | 1981-07-17 | 1983-01-26 | Citizen Watch Co Ltd | Electronic clock with dot matrix display device |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61176199A (en) | 1986-08-07 |
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