JPS60125550A - Rf coil for nmr-ct - Google Patents
Rf coil for nmr-ctInfo
- Publication number
- JPS60125550A JPS60125550A JP58234776A JP23477683A JPS60125550A JP S60125550 A JPS60125550 A JP S60125550A JP 58234776 A JP58234776 A JP 58234776A JP 23477683 A JP23477683 A JP 23477683A JP S60125550 A JPS60125550 A JP S60125550A
- Authority
- JP
- Japan
- Prior art keywords
- coil
- parallel
- magnetic field
- linear parts
- nmr
- 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
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
- G01R33/28—Details of apparatus provided for in groups G01R33/44 - G01R33/64
- G01R33/32—Excitation or detection systems, e.g. using radio frequency signals
- G01R33/34—Constructional details, e.g. resonators, specially adapted to MR
- G01R33/34046—Volume type coils, e.g. bird-cage coils; Quadrature bird-cage coils; Circularly polarised coils
- G01R33/34069—Saddle coils
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
- G01R33/44—Arrangements or instruments for measuring magnetic variables involving magnetic resonance using nuclear magnetic resonance [NMR]
- G01R33/48—NMR imaging systems
- G01R33/54—Signal processing systems, e.g. using pulse sequences ; Generation or control of pulse sequences; Operator console
- G01R33/56—Image enhancement or correction, e.g. subtraction or averaging techniques, e.g. improvement of signal-to-noise ratio and resolution
- G01R33/565—Correction of image distortions, e.g. due to magnetic field inhomogeneities
- G01R33/5659—Correction of image distortions, e.g. due to magnetic field inhomogeneities caused by a distortion of the RF magnetic field, e.g. spatial inhomogeneities of the RF magnetic field
Landscapes
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Magnetic Resonance Imaging Apparatus (AREA)
Abstract
Description
【発明の詳細な説明】
（イ） 産業上の利用分野
本発明は、核磁気共鳴を用いたコンピュータ・トモグラ
フィ（ＮＭＲ−ＣＴ）用ＲＦコイルに関する。DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an RF coil for computer tomography using nuclear magnetic resonance (NMR-CT).
（ロ）従来技術
ＮＭＲ−ＣＴにおいては、ＲＦフィルに高周波電流（Ｒ
Ｆ）を流すことによって回転磁場Ｈ１を発生させ、これ
によって物質中の原子核スピン（例えば水素原子核スピ
ン）を倒し、その後の緩和現象によって生じるＮＭＲ信
号を、同−又は別の受信専用のＲＦＩイルを用いて観測
する。この時のＨｌの空間的均一性が極めて重要であり
、一般にＲＦコイルの巻き数が多い程、コイルの幾何学
的な配置を調整でき、より広いＨｌの均一領域を得るこ
とができる。(b) In conventional NMR-CT, a high frequency current (R
F) is applied to generate a rotating magnetic field H1, which knocks down the nuclear spins in the material (for example, hydrogen nuclear spins), and transmits the NMR signal generated by the subsequent relaxation phenomenon to the same or another RFI illumination exclusively for reception. Observe using Spatial uniformity of Hl at this time is extremely important, and generally, the larger the number of turns of the RF coil, the more the geometrical arrangement of the coil can be adjusted, and the wider the uniform area of Hl can be obtained.
一フ５．ＮＭＲ−ＣＴにおいて使用するＲＦの周波数ｆ
’ｏは
で決まる。従って、ＲＦコイルは、ＲＦを効率良く印加
し、かつＮＭＲ信号を効率良く受信するために、（１）
式で決まる周波数を共振周波数とする共振回路になって
いる。5. RF frequency f used in NMR-CT
'o is determined by. Therefore, in order to efficiently apply RF and efficiently receive NMR signals, the RF coil has (1)
It is a resonant circuit whose resonant frequency is the frequency determined by the formula.
一般にコイルとコンデンサーから成る共振回路の共振周
波数ｆは
Ｌ；フィルのインダクタンス
Ｃ；コンデンサーの静電容量
で決まる。従って、静磁場ＨＯを強くすることにより、
使用するＲＦの周波数が高くなった場合には、Ｌ及びＣ
の小さいＲＦコイルを準備する必要がある。然るに現実
には、ＣはＲＦフィル自身の静電容量以外に、被検体を
ＲＦコイルボビン内に挿入することによって生じる浮遊
容量等の影響を含んだ容量であり、下限が存在する。こ
のため高周波のＲＦコイルを得るには、同コイルのＬを
小さくすることが要求され、それはコイルの巻き数を少
なくすることにより実現きれる。しかし乍ら、前述の様
に巻き数を少なくすればＨｌの均一領域が狭くなるとい
う重大な欠点が生じる。Generally, the resonant frequency f of a resonant circuit consisting of a coil and a capacitor is determined by L; the inductance of the fill, C; and the capacitance of the capacitor. Therefore, by increasing the static magnetic field HO,
If the RF frequency used becomes higher, L and C
It is necessary to prepare a small RF coil. However, in reality, C is a capacitance that includes the influence of stray capacitance caused by inserting the subject into the RF coil bobbin in addition to the capacitance of the RF filter itself, and there is a lower limit. Therefore, in order to obtain a high frequency RF coil, it is required to reduce L of the coil, which can be achieved by reducing the number of turns of the coil. However, as mentioned above, if the number of turns is reduced, a serious drawback arises in that the uniform region of Hl becomes narrower.
第１図に従来のＮＭＲ−ＣＴ用ＲＦコイルを示す。この
コイルは樹脂等からなる円筒ボビン（１）に、第２図の
展開図にも示す如く、上下２組のループ（２＞（３）を
直列接続し工装着した鞍型のものであり、ボビン〈１）
内に被検体が入る。この例での鞍型ＲＦコイルの総巻き
数は８Ｔであるが、Ｌを小きくするためにそれを６Ｔ、
４Ｔ、２Ｔと少なくすると、それに従ってＨｌの均一領
域も狭くなる。FIG. 1 shows a conventional RF coil for NMR-CT. This coil is a saddle-shaped coil in which two sets of upper and lower loops (2>(3)) are connected in series and attached to a cylindrical bobbin (1) made of resin or the like, as shown in the exploded view in Figure 2. Bobbin <1)
The subject enters inside. In this example, the total number of turns of the saddle-shaped RF coil is 8T, but in order to reduce L, it is changed to 6T.
If the value is reduced to 4T or 2T, the uniform area of Hl becomes narrower accordingly.
（ハ） 発明の目的
本発明は、Ｈｌの均一領域を狭くすることなく、Ｌの低
減を測ったＮＭＲ−ＣＴ用ＲＦ ：ｆｆイル庖提供する
ものである。(C) Object of the Invention The present invention provides an RF filter for NMR-CT that can reduce L without narrowing the Hl uniform region.
（ニ） 発明の構成
本発明のＮＭＲ−ＣＴＪＩＭＲＦコイルの特徴は、コイ
ルボビン軸に平行な少なくとも２本の直線部を並列接続
した点にある。(d) Structure of the Invention The NMR-CTJIMRF coil of the present invention is characterized in that at least two straight portions parallel to the coil bobbin axis are connected in parallel.
（ホ） 実施例
第３図及び第４図に夫々木発明による第１、第２の実施
例であるＮＭＲ−ＣＴ用ＲＦコイルを示す。尚これらの
図面は第２図と同種の展開図である。(E) Embodiment FIGS. 3 and 4 show RF coils for NMR-CT, which are the first and second embodiments of the invention. Note that these drawings are developed views of the same type as FIG. 2.
鞍型コイルにおいて、コイルボビン軸に平行な直線部分
（４ａ）（４ｂ’）・・・の数がＨｌの均一性に関し１
重要であるが、第３図、第４図の何れの例にあっても、
上記直線部分の数は第２図と同一であり、従ってＨｌの
均一性は第２図のものと変わらない。In a saddle-shaped coil, the number of straight line parts (4a) (4b') parallel to the coil bobbin axis is 1 with respect to the uniformity of Hl.
It is important to note that in both the examples in Figures 3 and 4,
The number of the straight line sections is the same as in FIG. 2, so the uniformity of H1 is the same as in FIG.
一方、第３図、第４図では、上記直線部分の近接するも
のどうし、適宜並列接続きれており、従って斯る鞍型コ
イルの総巻き数は第２図のものより少なくなる。具体的
には、第２図では８Ｔであったのに対し、第３図では４
Ｔ、第４図では２Ｔである。この様に、コイルの巻き数
が減るのでそのＬも小さくなる。On the other hand, in FIGS. 3 and 4, adjacent straight portions are properly connected in parallel, and therefore the total number of turns of the saddle-shaped coil is smaller than that in FIG. 2. Specifically, while it was 8T in Figure 2, it was 4T in Figure 3.
T, in FIG. 4 it is 2T. In this way, since the number of turns of the coil decreases, its L also decreases.
（へ）発明の効果
本発明によれば、ＲＦコイルにより発生するＨｌの均一
領域を狭くすることなく、コイルのＬを小さくしてより
高周波用のＲＦコイルを得ることができる。(f) Effects of the Invention According to the present invention, an RF coil for higher frequencies can be obtained by reducing L of the coil without narrowing the uniform region of Hl generated by the RF coil.
第１図は従来例を示すコイルの斜視図、第２図は同展開
図、第３図及び第４図は本発明の実施例を示すコイルの
展開図である。
（１）・・・コイルボビンFIG. 1 is a perspective view of a coil showing a conventional example, FIG. 2 is an exploded view of the same, and FIGS. 3 and 4 are exploded views of a coil showing an embodiment of the present invention. (1) Coil bobbin
Claims (1)
を並列接続したことを特徴とするＮＭＲ−ＣＴ用ＲＦコ
イル。(1) An RF coil for NMR-CT, characterized in that at least two straight portions parallel to the coil bobbin axis are connected in parallel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58234776A JPS60125550A (en) | 1983-12-12 | 1983-12-12 | Rf coil for nmr-ct |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58234776A JPS60125550A (en) | 1983-12-12 | 1983-12-12 | Rf coil for nmr-ct |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS60125550A true JPS60125550A (en) | 1985-07-04 |
Family
ID=16976187
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58234776A Pending JPS60125550A (en) | 1983-12-12 | 1983-12-12 | Rf coil for nmr-ct |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60125550A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60169748A (en) * | 1983-12-23 | 1985-09-03 | ゼネラル・エレクトリツク・カンパニイ | Rf coil for nmr |
| JPS60171439A (en) * | 1984-02-16 | 1985-09-04 | Yokogawa Hokushin Electric Corp | Coil for nmr image diagnosing apparatus |
| JPS61163611U (en) * | 1985-03-29 | 1986-10-09 | ||
| EP0273484A2 (en) * | 1986-11-27 | 1988-07-06 | Koninklijke Philips Electronics N.V. | Magnetic resonance imaging apparatus comprising a stacked surface coil system |
| JP2007101550A (en) * | 2005-10-06 | 2007-04-19 | Bruker Biospin Ag | Electrically symmetric nmr coil having coil connected in series |
| JP2008209213A (en) * | 2007-02-26 | 2008-09-11 | Hitachi Ltd | Rf coil |
-
1983
- 1983-12-12 JP JP58234776A patent/JPS60125550A/en active Pending
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60169748A (en) * | 1983-12-23 | 1985-09-03 | ゼネラル・エレクトリツク・カンパニイ | Rf coil for nmr |
| JPH0350541B2 (en) * | 1983-12-23 | 1991-08-02 | Gen Electric | |
| JPS60171439A (en) * | 1984-02-16 | 1985-09-04 | Yokogawa Hokushin Electric Corp | Coil for nmr image diagnosing apparatus |
| JPS61163611U (en) * | 1985-03-29 | 1986-10-09 | ||
| JPH0323208Y2 (en) * | 1985-03-29 | 1991-05-21 | ||
| EP0273484A2 (en) * | 1986-11-27 | 1988-07-06 | Koninklijke Philips Electronics N.V. | Magnetic resonance imaging apparatus comprising a stacked surface coil system |
| JP2007101550A (en) * | 2005-10-06 | 2007-04-19 | Bruker Biospin Ag | Electrically symmetric nmr coil having coil connected in series |
| JP4489744B2 (en) * | 2005-10-06 | 2010-06-23 | ブルーカー バイオシュピン アー・ゲー | Electrically symmetric NMR coil with windings connected in series |
| JP2008209213A (en) * | 2007-02-26 | 2008-09-11 | Hitachi Ltd | Rf coil |
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