JPS63128608A - Segment for permanent magnet type mri device - Google Patents
Segment for permanent magnet type mri deviceInfo
- Publication number
- JPS63128608A JPS63128608A JP61273894A JP27389486A JPS63128608A JP S63128608 A JPS63128608 A JP S63128608A JP 61273894 A JP61273894 A JP 61273894A JP 27389486 A JP27389486 A JP 27389486A JP S63128608 A JPS63128608 A JP S63128608A
- Authority
- JP
- Japan
- Prior art keywords
- segment
- magnetic field
- permanent magnets
- segments
- magnets
- 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.)
- Pending
Links
- 230000003068 static effect Effects 0.000 claims description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 abstract description 10
- 229910052742 iron Inorganic materials 0.000 abstract description 5
- 238000002595 magnetic resonance imaging Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 3
- 239000000919 ceramic Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Abstract
Description
【発明の詳細な説明】
［発明の目的］
（産業上の利用分野）
本発明は永久磁石型ＭＲＩ装置に於て静磁場を形成する
のに用いるセグメントに関する。DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a segment used for forming a static magnetic field in a permanent magnet type MRI apparatus.
（従来の技術）
磁気共鳴イメージング装置（ＭＲＩ装置）においては、
均一な磁場空間（その均一度は百万分のｌという単位：
ＰＰｍという単位でしばしば表わされる）を得ることが
非常に重要であり、ＭＲ■の磁石の歴史は、この均一性
をいかに広い空間にわたって得るかということの歴史で
もあった。(Prior art) In a magnetic resonance imaging device (MRI device),
Uniform magnetic field space (uniformity is in units of l/million:
It is very important to obtain the uniformity (often expressed in units of PPm), and the history of MR■ magnets is also the history of how to obtain this uniformity over a wide space.
永久磁石型のＭＲＩ装置において、ある領域内に磁場の
均一領域をつくり出す場合、第３図に示すように磁場の
均一領域Ａに磁気ダイポールの集りがあると考え、その
ダイポール群かっくり出す磁力線に着目すると考えやす
い。When creating a uniform magnetic field region in a permanent magnet type MRI device, it is assumed that there is a collection of magnetic dipoles in the uniform magnetic field region A, as shown in Figure 3, and the lines of magnetic force that emerge from the dipole group are It's easy to think if you pay attention to it.
例えば、磁場の均一領域Ａを得るには、その均一領域Ａ
の周りに、磁界を発生するセグメントを配設し、その各
セグメント各々の磁場方向（第４図矢印方向）を前記ダ
イポールが、そのセグメントの位置につくり出す磁場方
向と一致さることにより均一領域Ａを得ることができ、
このようにして磁場の均一領域Ａを形成したものとして
、従来、特開昭６０−２６０１０７号公報に見られるよ
うなセグメント式リング磁石がある（第４図参照）。For example, to obtain a uniform region A of the magnetic field, the uniform region A
A uniform area A is created by arranging segments that generate a magnetic field around the , and aligning the direction of the magnetic field of each segment (in the direction of the arrow in Figure 4) with the direction of the magnetic field generated by the dipole at the position of the segment. you can get
As a device in which the uniform magnetic field region A is formed in this manner, there is a segment type ring magnet as disclosed in Japanese Patent Application Laid-Open No. 60-260107 (see FIG. 4).
（発明が解決しようとする問題点）
ところが、第４図に示したＬ述のようなリング磁石１０
は、その各セグメント１２を４つの磁性材料ブロック即
ち４つの永久磁石で構成していたため１次ぎのような問
題があった。(Problem to be solved by the invention) However, the ring magnet 10 as shown in FIG.
Because each segment 12 was constructed from four blocks of magnetic material, that is, four permanent magnets, this caused a first-order problem.
■ 各セグメントが４つの永久磁石で構成されているの
で各セグメントの磁極面の調整が困難である。■ Since each segment is composed of four permanent magnets, it is difficult to adjust the magnetic pole face of each segment.
■ リンク状磁石ｌＯの開口径の形状をかえる場合、例
えば第４図に示すセグメントｌ ２ｅ。(2) When changing the shape of the opening diameter of the link magnet lO, for example, the segment l2e shown in FIG.
１２ｍの縦方向長さを変えてリング状磁石１０の形状を
楕円形とする場合には、これらセグメント１２ｅ、１２
ｍの磁極面を再調整しなければならず、この調整が上述
のように困難であることからリング状磁石ｌＯの形状を
変えることも又困難である。When the ring-shaped magnet 10 is made into an elliptical shape by changing the longitudinal length of 12 m, these segments 12e, 12
The magnetic pole face of m must be readjusted, and since this adjustment is difficult as described above, it is also difficult to change the shape of the ring-shaped magnet lO.
■ 又、上述のように各セグメントの磁極面の調整が困
難であるからリング状磁石ｌＯにより形成される領域Ａ
の均一性の調整も困難である。■ Also, as mentioned above, since it is difficult to adjust the magnetic pole face of each segment, the area A formed by the ring-shaped magnet lO
It is also difficult to adjust the uniformity of
■ 各セグメントは磁石（通常、セラミック系のフェラ
イト、希土類等）で構成されているので加工性が悪く、
このためポールピースあるいは鉄等による磁場補正用突
起ネジ等をとりつけることが困難である。■ Each segment is composed of a magnet (usually ceramic ferrite, rare earth, etc.), so it is difficult to process.
For this reason, it is difficult to attach a pole piece or a projection screw made of iron or the like for magnetic field correction.
本発明の目的は、以上のうような問題点を解決し、均一
な磁場空間を従来に比べて容易に得ることの出来る永久
磁石型ＭＲＩ装置用セグメントを提供することにある。An object of the present invention is to solve the above-mentioned problems and provide a segment for a permanent magnet type MRI apparatus that can more easily obtain a uniform magnetic field space than before.
［発明の構成］
（問題点を解決するための手段）
上記目的を達成するため本発明セグメントは、２つの永
久磁石と、これら永久磁石の間にあって両磁石を磁気的
に結合するヨークとで構成した。[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the segment of the present invention is composed of two permanent magnets and a yoke that is located between these permanent magnets and magnetically couples both magnets. did.
（作用） 本発明は上記の構成としたので、次のように作用する。(effect) Since the present invention has the above configuration, it operates as follows.
セグメントを２つの永久磁石と、ヨークとで構成したの
で、４つの永久磁石から成る従来のセグメントに比べて
磁極面の調整が容易である。Since the segment is composed of two permanent magnets and a yoke, it is easier to adjust the magnetic pole surface compared to a conventional segment composed of four permanent magnets.
（実施例） 以下図示の実施例について説明する。(Example) The illustrated embodiment will be described below.
〈実施例１〉
第１図は本発明に係る永久磁石型ＭＲＩ装置用セグメン
トの第１実施例を示す正面図である。<Embodiment 1> FIG. 1 is a front view showing a first embodiment of a segment for a permanent magnet type MRI apparatus according to the present invention.
このセグメントは１図示のように２つの永久磁石１．１
と、これら永久磁石の間にあって両磁石を磁気的に結合
する鉄ヨーク２とで構成されている。This segment consists of two permanent magnets 1.1 as shown.
and an iron yoke 2 that is located between these permanent magnets and magnetically couples both magnets.
このようなセグメントによれば、図示矢印に示すように
磁場方向が形成され次ぎのような作用効果を奏する。According to such a segment, the direction of the magnetic field is formed as shown by the arrow in the figure, and the following effects are achieved.
■ セグメントか２つの永久磁石ｌと、ヨーク２とで構
成されているので、４つの永久磁石から成る従来のセグ
メントに比べて磁極面の調整が容易である。(2) Since the segment is composed of two permanent magnets 1 and the yoke 2, it is easier to adjust the magnetic pole surface compared to the conventional segment composed of four permanent magnets.
■ 例えば第４図に示したリング状磁石ｌＯと同様な磁
石を形成し、その開口径の形状をかえる場合、少なくと
も第４図に示したセグメント１２ｅ、１２ｍの位置に相
当するセグメントのみを本実施例のセグメントで構成し
、そのセグメントのヨーク２の長さを変えるだけで磁極
面の調整をくるわせずに開口径の形状を楕円形に変える
ことができる。■ For example, when forming a magnet similar to the ring-shaped magnet 1O shown in Fig. 4 and changing the shape of its opening diameter, at least only the segments corresponding to the positions of segments 12e and 12m shown in Fig. 4 are used in this implementation. By simply changing the length of the yoke 2 of the segment shown in the example, the shape of the opening diameter can be changed to an ellipse without adjusting the magnetic pole surface.
■ 又ヨーク２の長さを変えるだけで容易に磁場強度を
変えることができる。(2) Moreover, the magnetic field strength can be easily changed by simply changing the length of the yoke 2.
■ 又本実施例のセグメントでリング状磁石を形成した
場合、各セグメントのヨーク２の厚さ、成るいは永久磁
石ｌの種類を可変することにより、磁場の均一性の調整
も容易である。(2) Furthermore, when a ring-shaped magnet is formed from the segments of this embodiment, the uniformity of the magnetic field can be easily adjusted by varying the thickness of the yoke 2 of each segment or the type of permanent magnet l.
■ ヨーク２は鉄製で加工か容易であるのでポールピー
スあるいは、鉄等による磁場補正用突起ネジ等をとりつ
けることか容易である。(2) Since the yoke 2 is made of iron and is easily machined, it is easy to attach a pole piece or a protruding screw made of iron or the like for magnetic field correction.
〈実施例２〉
本実施例のセグメントは、第２図に示すようにそのヨー
ク２を上下２ａ、２ｂに２分割できるようにしたもので
ある。<Embodiment 2> The segment of this embodiment is such that the yoke 2 can be divided into two parts, upper and lower parts 2a and 2b, as shown in FIG.
このようにすれば、リング状磁石を形成した場合、少な
くとも先述したセグメント１２ｅ、１２ｍの位置に相当
するセグメントを本実施例のセグメントで構成すること
により磁極面の調整をくるわせずにリング状磁石を上下
に２分割化できるため、リング状磁石を組立分割するの
に非常に有用である。In this way, when a ring-shaped magnet is formed, by configuring at least the segments corresponding to the positions of the segments 12e and 12m described above with the segments of this embodiment, the ring-shaped magnet can be formed without having to adjust the magnetic pole surface. Since it can be divided into upper and lower halves, it is very useful for assembling and dividing ring-shaped magnets.
以上本発明の実施例について説明したが、本発明は上記
実施例に限定されるものではなく、本発明の要旨の範囲
内において適宜変形実施可能であることは言うまでもな
い。Although the embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to the above embodiments, and can be modified as appropriate within the scope of the gist of the present invention.
例えば本発明のセグメントは、リング磁石に限らずどの
ような形状の磁石にも適応できる。For example, the segment of the present invention is applicable not only to ring magnets but also to magnets of any shape.
［発明の効果］
以上詳述したように本発明によれば、均一な磁場空間を
従来に比べて容易に得ることが出来る。[Effects of the Invention] As detailed above, according to the present invention, a uniform magnetic field space can be obtained more easily than in the past.
第１図は本発明に係る永久磁石型ＭＨＩ装置用セグメン
トの第１実施例を示す正面図、第２図は同上第２実施例
の正面図、第３図は磁界の説明図、第４図は従来のセグ
メントで構成したリング状磁石の斜視図である。
ｌ・・・永久磁石、２・・・ヨーク。
第 ３ 図Fig. 1 is a front view showing a first embodiment of a permanent magnet type MHI device segment according to the present invention, Fig. 2 is a front view of the second embodiment of the same, Fig. 3 is an explanatory diagram of the magnetic field, and Fig. 4 1 is a perspective view of a conventional ring-shaped magnet made up of segments. l...Permanent magnet, 2...Yoke. Figure 3
Claims (2)
に用いるセグメントであって、２つの永久磁石と、これ
ら永久磁石の間にあって両磁石を磁気的に結合するヨー
クとから成る永久磁石型ＭＲＩ装置用セグメント。(1) A permanent magnet segment used to form a static magnetic field in a permanent magnet MRI device, which consists of two permanent magnets and a yoke that is located between these permanent magnets and magnetically couples both magnets. Segment for type MRI machine.
項記載の永久磁石型ＭＲＩ装置用セグメント。(2) Claim 1 in which the yoke is divisible
A segment for a permanent magnet type MRI apparatus as described in .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61273894A JPS63128608A (en) | 1986-11-19 | 1986-11-19 | Segment for permanent magnet type mri device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61273894A JPS63128608A (en) | 1986-11-19 | 1986-11-19 | Segment for permanent magnet type mri device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS63128608A true JPS63128608A (en) | 1988-06-01 |
Family
ID=17534053
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61273894A Pending JPS63128608A (en) | 1986-11-19 | 1986-11-19 | Segment for permanent magnet type mri device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63128608A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0382447A (en) * | 1989-08-28 | 1991-04-08 | Shin Etsu Chem Co Ltd | Magnetic field generator |
| US5232295A (en) * | 1990-09-18 | 1993-08-03 | Oki Electric Industry Co., Ltd. | Wire print head and process for fabricating it |
| JP2005185387A (en) * | 2003-12-25 | 2005-07-14 | Hitachi Ltd | Mri apparatus |
-
1986
- 1986-11-19 JP JP61273894A patent/JPS63128608A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0382447A (en) * | 1989-08-28 | 1991-04-08 | Shin Etsu Chem Co Ltd | Magnetic field generator |
| US5232295A (en) * | 1990-09-18 | 1993-08-03 | Oki Electric Industry Co., Ltd. | Wire print head and process for fabricating it |
| JP2005185387A (en) * | 2003-12-25 | 2005-07-14 | Hitachi Ltd | Mri apparatus |
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