JPH0461484B2 - - Google Patents
Info
- Publication number
- JPH0461484B2 JPH0461484B2 JP61082078A JP8207886A JPH0461484B2 JP H0461484 B2 JPH0461484 B2 JP H0461484B2 JP 61082078 A JP61082078 A JP 61082078A JP 8207886 A JP8207886 A JP 8207886A JP H0461484 B2 JPH0461484 B2 JP H0461484B2
- Authority
- JP
- Japan
- Prior art keywords
- coil
- magnetic field
- winding frame
- gradient magnetic
- noise
- 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
- 238000004804 winding Methods 0.000 claims description 26
- 238000003384 imaging method Methods 0.000 claims description 8
- 230000005284 excitation Effects 0.000 description 7
- 230000000694 effects Effects 0.000 description 4
- 230000003068 static effect Effects 0.000 description 4
- 230000002238 attenuated effect Effects 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 238000005481 NMR spectroscopy Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- 230000000644 propagated effect Effects 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
Landscapes
- Magnetic Resonance Imaging Apparatus (AREA)
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は巻枠に伝達されるコイルの電磁振動に
よる騒音を低減させるに好適なMRイメージング
装置用傾斜磁場コイルに関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a gradient magnetic field coil for an MR imaging apparatus suitable for reducing noise due to electromagnetic vibration of a coil transmitted to a winding frame.
核磁気共鳴現象を利用したいわゆるMRイメー
ジング装置では、照射観察面の決定等のための磁
場勾配が必要であり、この目的のため、静磁場コ
イルの内側には、Ｘ，Ｙ，Ｚの各方向に任意の傾
斜磁場を発生する３組のコイルが取付けられてい
る。これらＸ，Ｙ，Ｚ各コイルは、独立した専用
電源からの制御された電流（一般には一定の間隔
を有したパルス電流）で励磁される。
So-called MR imaging devices that utilize nuclear magnetic resonance phenomena require magnetic field gradients to determine the irradiation observation plane, etc. For this purpose, magnetic field gradients are installed inside the static magnetic field coil in each of the X, Y, and Z directions. Three sets of coils are attached to generate arbitrary gradient magnetic fields. Each of these X, Y, and Z coils is energized with a controlled current (typically a pulsed current having regular intervals) from an independent, dedicated power source.
傾斜磁場発生用コイルは非常に強力な静磁場
（一般に1500から3000ガウス）内におかれる。こ
のため、励磁電流が流れると、静磁場の方向と当
該コイルに流れる電流方向で決まる電磁力が作用
する。特にパルス電流で駆動する場合には瞬間的
に強力な電磁力が作用するため、コイルが振動
し、それがコイル固定部を通して巻枠に伝えら
れ、騒音源（打撃音は又は共鳴音）となる。MR
イメージング装置は人体の測定を目的とし、被検
査等は傾斜磁場の内部に入ることになるため、こ
れらの打撃音が発生すると心理的な圧迫感を与え
る原因となり好ましくない。
The gradient magnetic field generating coils are placed in a very strong static magnetic field (generally 1500 to 3000 Gauss). Therefore, when an excitation current flows, an electromagnetic force determined by the direction of the static magnetic field and the direction of the current flowing through the coil acts. In particular, when driving with pulsed current, a strong electromagnetic force acts momentarily, causing the coil to vibrate, which is transmitted to the winding frame through the coil fixing part and becomes a noise source (impact sound or resonance sound). . MR
Since the purpose of the imaging apparatus is to measure the human body, and the subject to be inspected is placed inside a gradient magnetic field, the generation of these impact sounds is undesirable as it causes psychological pressure.
本発明の目的は、打撃音の小さい、被検査者に
圧迫感を与えることの少ないMRイメージング装
置用傾斜磁場コイル装置を提供するにある。 An object of the present invention is to provide a gradient magnetic field coil device for an MR imaging device that produces low impact noise and does not give a feeling of pressure to a subject.
上記目的は、傾斜磁場コイルの筒状の形状を有
する巻枠に、任意の形状の空間を、任意の数（複
数個）だけ、傾斜磁場コイルの接触する部位を避
けて設けることにより達成される。
The above object is achieved by providing an arbitrary number (plurality) of spaces of any shape in the cylindrical winding frame of the gradient magnetic field coil, avoiding the parts that the gradient magnetic field coil contacts. .
傾斜磁場コイルの接触する部位を避けて巻枠に
任意の形状の空間を任意の数（複数個）だけ設け
ることにより、巻枠に発生する衝撃音は、巻枠の
筒状面を分散して伝播されるため減衰し、また、
巻枠に発生する反響音は巻枠の筒状面の空間より
逃げるので減少する。更に、巻枠に発生する音
は、「開管の振動」として振動数を求めることが
できるが、巻枠に任意の形状の空間をあけること
により振動数を変えることができるため、巻枠の
固有振動数とずらすことができ共鳴音を防止する
ことができる。その上巻枠に任意の形状の空間が
あるため、巻枠がいわゆる「開管」を形成しえな
いため「開閉の振動」の発生が減少でき、騒音の
防止ができる。またさらに巻枠が筒形のバスケツ
ト状になるので、軽量化でき、風通しも良いので
冷却効果のよくなり、かつ質量も少なくなるので
反響音も少なくなり低騒音の傾斜磁場発生用コイ
ル装置を得ることができる。
By providing an arbitrary number (multiple spaces) of an arbitrary shape in the reel while avoiding the contact area of the gradient magnetic field coil, the impact noise generated in the reel is dispersed over the cylindrical surface of the reel. Because it is propagated, it is attenuated, and
The reverberant sound generated in the winding frame is reduced because it escapes through the space on the cylindrical surface of the winding frame. Furthermore, the frequency of the sound generated in the reel can be determined as ``vibration of an open tube,'' but the frequency can be changed by creating a space of any shape in the reel. It can deviate from the natural frequency and prevent resonance. Furthermore, since the winding frame has a space of an arbitrary shape, the winding frame cannot form a so-called "open pipe", so the occurrence of "opening/closing vibration" can be reduced, and noise can be prevented. Furthermore, since the winding frame is shaped like a cylindrical basket, it can be made lighter, and it has good ventilation, which improves the cooling effect, and the mass is also reduced, so there is less reverberant sound, resulting in a low-noise coil device for generating a gradient magnetic field. be able to.
以下本発明の一実施例を説明する。 An embodiment of the present invention will be described below.
第２図はMRイメージング装置の構成を示す。
制御装置１は、各装置へ種々の命令を一定のタイ
ミングで出力する。高周波パルス発生器２の出力
は電力増巾器３で増巾されコイル４を励振する。
コイル４は受信コイルを兼用しており、信号成分
は増巾器５を通り、検波器６で検波された後、信
号処理装置７で画像に変換される。傾斜磁場発生
コイルユニツト８は、巻枠９とＺ方向コイル１０
とその外側に互いに直交して配置されるＸ方向コ
イル１１，Ｙ方向コイル１２から成りそれぞれ励
振電源１４で駆動される。静磁場の発生はコイル
１５で行い励振電源１６で駆動される。被検査者
１７はこれらの磁石の中心部におかれる。 Figure 2 shows the configuration of the MR imaging device.
The control device 1 outputs various commands to each device at constant timing. The output of the high frequency pulse generator 2 is amplified by a power amplifier 3 and excites a coil 4.
The coil 4 also serves as a receiving coil, and the signal component passes through an amplifier 5, is detected by a detector 6, and then converted into an image by a signal processing device 7. The gradient magnetic field generating coil unit 8 includes a winding frame 9 and a Z direction coil 10.
It consists of an X-direction coil 11 and a Y-direction coil 12 which are arranged perpendicularly to each other on the outside thereof, and are each driven by an excitation power source 14. A static magnetic field is generated by a coil 15 and driven by an excitation power source 16. The subject 17 is placed at the center of these magnets.
第３図，第４図は傾斜磁場発生用コイルユニツ
トの基本構造を示す。第３図はＺ方向コイル１０
の取付を示す。１０は巻枠９の両端部に円周方向
に巻かれた２組のコイルから成り、端子１０′は
各コイルの端末に接続され外部配線との結合を行
う（１０′詳細構造省略）。第４図はＸ方向コイル
１１及びＹ方向コイル１２の取付を示す。コイル
１１及び１２は図示のような鞍形のコイルでコイ
ル１０り外側に重ね、更に機械的に90度ずらせて
取付けられている。端子１１′，１２′は各コイル
の端末に接続されている（１１′，１２′詳細構造
省略）。また巻枠９は、非金属、非磁性体（例え
ばフエノール樹脂やFRPなど）で作られ、その
形状は円筒状の形状になつている。このため傾斜
磁場コイルにパルス電流による励磁電流が流れる
と、コイルに瞬間的に強力な電磁力が作用するた
め、コイルが振動し、それがコイル固定部を通し
て巻枠に伝えられ騒音源（打撃音，反響音又は共
鳴音）となる。 Figures 3 and 4 show the basic structure of the gradient magnetic field generating coil unit. Figure 3 shows the Z-direction coil 10.
The installation is shown. Reference numeral 10 consists of two sets of coils wound in the circumferential direction at both ends of the winding frame 9, and terminals 10' are connected to the terminals of each coil for coupling with external wiring (detailed structure of 10' is omitted). FIG. 4 shows the installation of the X-direction coil 11 and the Y-direction coil 12. The coils 11 and 12 are saddle-shaped coils as shown, and are mounted on the outside of the coil 10 so as to be mechanically shifted by 90 degrees. Terminals 11' and 12' are connected to the terminals of each coil (detailed structure of 11' and 12' is omitted). Further, the winding frame 9 is made of a non-metallic, non-magnetic material (for example, phenol resin, FRP, etc.), and has a cylindrical shape. For this reason, when an excitation current by a pulse current flows through the gradient magnetic field coil, a strong electromagnetic force acts on the coil momentarily, causing the coil to vibrate, which is transmitted to the winding frame through the coil fixing part, causing noise (impact noise). , reverberation or resonance).
第１図は傾斜磁場コイルの構造を示す外観図で
ある。この図において巻枠９は、任意の形状（図
示では角形）の空間１３を、任意の数（複数個）
でけ設けてあり、巻枠９をいわゆる円筒形のバス
ケツト状に形成しているものである。もちろん、
コイルを巻枠に真円に巻きつけること、およびコ
イルと巻枠を確実に固定するため、コイルと巻枠
との接触する部位には空間１３を設けないことな
どの配慮が望まれた。 FIG. 1 is an external view showing the structure of a gradient magnetic field coil. In this figure, the winding frame 9 has an arbitrary number (plurality) of spaces 13 of an arbitrary shape (square in the illustration).
The winding frame 9 is formed into a so-called cylindrical basket shape. of course,
In order to wind the coil around the winding frame in a perfect circle and to securely fix the coil and the winding frame, consideration should be given to not providing a space 13 in the area where the coil and the winding frame come into contact.
このような構造によれば、各コイルの振動によ
る打撃音は、巻枠の外壁を分散されて伝達する
為、減衰させられるし、また巻枠自身の固有振動
数に対し、巻枠の振動数（開管の振動）をずらす
ことができるので、巻枠が共鳴筒となることはな
くなり、騒音を減少できる。またさらに、巻枠が
任意の形状の空間を有してあるので、いわゆる
「開管」を形成しえず、それゆえ「開閉の振動」
による騒音の発生を減少でき、低騒音の傾斜磁場
発生用コイルを得ることができる。 According to this structure, the impact sound caused by the vibration of each coil is transmitted through the outer wall of the winding frame in a dispersed manner, so it is attenuated. (vibration of the open tube) can be shifted, so the winding frame no longer becomes a resonant cylinder, and noise can be reduced. Furthermore, since the winding frame has a space of an arbitrary shape, it is impossible to form a so-called "open pipe", and therefore "opening/closing vibration" occurs.
Therefore, it is possible to reduce the noise generated by the magnetic field, and to obtain a low-noise gradient magnetic field generating coil.
なお、「開管の振動」における振動数は次式で
求められる。 In addition, the frequency of "vibration of an open pipe" is determined by the following formula.
Ｎ＝ｖ／２
ただし、Ｎは振動数、ｖは音速〔340m／sec
（15℃）〕、は開閉の長さである。 N=v/2 However, N is the frequency of vibration, and v is the speed of sound [340m/sec
(15℃)] is the opening/closing length.
本発明によれば、傾斜磁場コイルにパルス電源
からの励磁電流を流すことによつて、巻枠に発生
する騒音（打撃音、共鳴音）を減少することがで
き、傾斜磁場の内部にいる被検査者の心理的な圧
迫感を与えることがなく撮影が可能になる。
According to the present invention, by passing an excitation current from a pulsed power source through the gradient magnetic field coil, it is possible to reduce the noise generated in the winding frame (impact sound, resonance sound), and to reduce the noise generated in the winding frame. It becomes possible to take pictures without giving the examiner a psychological feeling of pressure.
また傾斜磁場コイルの巻枠に空間を設け、筒形
のバスケツト状にするため、軽量にできるため、
全体の構造も簡単にすることができる。 In addition, since a space is provided in the winding frame of the gradient magnetic field coil to form a cylindrical basket shape, it can be made lightweight.
The overall structure can also be simplified.
又更に円筒形のバスケツト状であるため空間か
ら空気の流通が良く、従つて冷却効果もアツプす
る。 Furthermore, since it is shaped like a cylindrical basket, air can circulate well from the space, and therefore the cooling effect is enhanced.
第１図は本発明による一実施例の傾斜磁場コイ
ル装置の斜視図、第２図はMRイメージング装置
の原理構成を示すブロツク図、第３図，第４図は
傾斜磁場発生用コイル装置の基本構造を示す斜視
図である。
１……制御装置、２……高周波パルス発生器、
３……電力増巾器、４……コイル、５……増巾
器、６……検波器、７……信号処理装置、８……
傾斜磁場発生用コイル、９……巻枠、１０……Ｚ
方向コイル、１０′……端子、１１……Ｙ方麦コ
イル、１１′……端子、１２……Ｙ方向コイル、
１２′……端子、１３……空間、１４……励磁電
源、１５……コイル、１６……励磁電源、１７…
…被検査者。
Fig. 1 is a perspective view of a gradient magnetic field coil device according to an embodiment of the present invention, Fig. 2 is a block diagram showing the principle configuration of an MR imaging device, and Figs. 3 and 4 are basics of a gradient magnetic field generating coil device. FIG. 3 is a perspective view showing the structure. 1...Control device, 2...High frequency pulse generator,
3... Power amplifier, 4... Coil, 5... Amplifier, 6... Detector, 7... Signal processing device, 8...
Gradient magnetic field generation coil, 9...winding frame, 10...Z
Direction coil, 10'...terminal, 11...Y direction coil, 11'...terminal, 12...Y direction coil,
12'...terminal, 13...space, 14...excitation power supply, 15...coil, 16...excitation power supply, 17...
...Tested person.
Claims (1)
メージング装置用傾斜磁場コイル装置において、
前記巻枠に任意の形状の空間を、任意の数だけ、
前記コイルの接触する部位を避けて設けたことを
特徴とするMRイメージング装置用傾斜磁場コイ
ル装置。1. In a gradient magnetic field coil device for an MR imaging device in which a gradient magnetic field coil is wound around a cylindrical winding frame,
Create any number of spaces of any shape in the winding frame,
1. A gradient magnetic field coil device for an MR imaging device, characterized in that the coil device is provided so as to avoid a contacting portion of the coil.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61082078A JPS62239503A (en) | 1986-04-11 | 1986-04-11 | Inclined magnetic field coil device for mr imaging device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61082078A JPS62239503A (en) | 1986-04-11 | 1986-04-11 | Inclined magnetic field coil device for mr imaging device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62239503A JPS62239503A (en) | 1987-10-20 |
| JPH0461484B2 true JPH0461484B2 (en) | 1992-10-01 |
Family
ID=13764426
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61082078A Granted JPS62239503A (en) | 1986-04-11 | 1986-04-11 | Inclined magnetic field coil device for mr imaging device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS62239503A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2886871B2 (en) * | 1988-12-23 | 1999-04-26 | 株式会社日立製作所 | Nuclear magnetic resonance equipment |
| JP2006528899A (en) * | 2003-05-22 | 2006-12-28 | コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ | Magnetic resonance imaging apparatus having sound absorbing means |
-
1986
- 1986-04-11 JP JP61082078A patent/JPS62239503A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62239503A (en) | 1987-10-20 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |