CN2481283Y - Vortex eliminating device for medical nuclear magnetic resonance imaging - Google Patents
Vortex eliminating device for medical nuclear magnetic resonance imaging Download PDFInfo
- Publication number
- CN2481283Y CN2481283Y CN 01245762 CN01245762U CN2481283Y CN 2481283 Y CN2481283 Y CN 2481283Y CN 01245762 CN01245762 CN 01245762 CN 01245762 U CN01245762 U CN 01245762U CN 2481283 Y CN2481283 Y CN 2481283Y
- Authority
- CN
- China
- Prior art keywords
- layer
- metallic laminations
- eddy current
- magnetic resonance
- resonance imaging
- 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 - Fee Related
Links
Images
Landscapes
- Magnetic Resonance Imaging Apparatus (AREA)
Abstract
The utility model relates to a vortex eliminating device for medical nuclear magnetic resonance imaging, which comprises a metal lamination layer and an insulating layer. The utility model is characterized in that the metal lamination layer comprises at least two layers, the insulating layer can separate the two adjacent metal lamination layers, the metal lamination layer consists of a metal lamination strip to be arrayed, the metal lamination strip is formed by a metal plate to be overlapped, the metal lamination strip in the adjacent metal lamination layers is arranged an intercrossing manner; the utility model is used to be arranged between a machine head and a gradient coil, which can partition the gradient coil with an pole plate so as to shorten a time of gradient raising and improve the imaging quality.
Description
This utility model belongs to the mr imaging technique field, particularly relates to a kind of device that eddy current is eliminated in the medical magnetic resonance imaging that is used for.
In background technology, the medical magnetic resonance imaging device comprises column and imaging space, is symmetrically arranged with gradient coil, head, magnetic and pole plate successively in the both sides up and down of imaging space, and gradient coil is centered on mutually by grading ring.The imaging of medical magnetic resonance is the strong fast-changing gradient fields of stack on magnetostatic field very uniformly, and these gradient fields are that the gradient coil by the current impulse that is loaded with accurate control produces, and the imaging volume has been determined in the space at gradient fields place.Gradient coil is made up of three groups of coils, has represented X, Y, three directions of Z respectively, and relation is orthogonal between them.Because gradient coil is near head, produce the eddy current of X, Y, three directions of Z applying fail to be convened for lack of a quorum on the head induction of big Pulse Electric on the gradient coil, their relation that also is orthogonal each other, direction is opposite with the gradient current direction.The size of eddy current is decided by the size of the pulse current that applies on the gradient coil, and the electric current that the applies maelstrom of healing is also bigger, and vice versa.The life period of eddy current is decided by the length of eddy current flow path, and the time that the shorter eddy current in path exists is shorter, and the eddy current life period is shorter, and the faradic time of its generation is shorter, and just shorter to the influence time of magnetostatic field, the picture quality that finally obtains is just high.In medical examination, people require more and more higher to the gradient fields in the medical magnetic resonance imaging, the gradient pulse electric current is increasing, cause the eddy current on the pole plate also more and more big, the result is that gradient rising edge time lengthening, magnetic resonance merit system can weaken, image quality decrease, therefore, the solution eddy current problem has become the key in the nuclear magnetic resonance.
Have in the magnetic resonance imaging system of vertical magnetic field in style of opening, usually adopt at the head external coating to have the amorphous metal mixture coating of certain elimination venturi effect or with the method for amorphous metal material head, to reach the purpose that reduces eddy current.It is better that this method is eliminated the effect of eddy current, but cost an arm and a leg, complex process, cost be high, is difficult to generally use popularization.
For example: put down in writing a kind of " being used for reducing the device of the eddy current of MR imaging apparatus " on the patent application document of disclosed publication number CN110971A on the 31st in May nineteen ninety-five, this device is made up of C shape magnet, pole shoe, permanent magnet and gradient coil.Near the gradient coil place, adopt ferruginous thin slice to be made for the lip-deep laminated insulation dish of pole shoe very, the structure of dish has two kinds: in the planar orientation of rim pole-shoe face that part of, they are made of the annular slab that cuts into from iron plate; In the part that the axle along pole-shoe face is orientated, they are made of the ring with banded iron plate spiral coiled.The thin plate-like or the ring-type ferromagnetic parts that are stacked to by multilamellar are housed on the pole shoe surface, and each layer is by lacquer or fixing glue and adjacently situated surfaces point insulating.On these layers, cut out narrow radial slot before the closed assembly, to reduce eddy current.Groove in the adjacent layer is indexed into and does not overlap, thereby causes even magnetic flux on all directions.
On the patent application document of disclosed publication number CN 1252977A on May 17th, 2000, put down in writing " magnetic pole strength of the low magnetic hysteresis of the eddy current in the nuclear magnetic resonance ", it has pole piece, that each pole piece has is respect to one another, be defined as the volumetrical pole-face of picture, excitation unit with magnet exciting coil and pole piece, described pole-face comprises a plurality of magnetic piece with lamination, each lamination is made of the amorphous ferromagnetic material, described lamination is separated by substrate and combines in this substrate, and the arrangement of lamination is arranged essentially parallel to institute's pole-face.This structure has reduced induced eddy current in pole-face, has also reduced remanent magnetization simultaneously, thereby can improve the quality of image.
More than the numerical procedure of two pieces of described reduction eddy current of disclosed patent application document, there is not to solve the problem of the mobile path length of eddy current, the magnetic field that its vortex induction electric current produces to magnetostatic field to influence the persistent period still longer, need further to improve to eliminate vortex device and just can better improve picture quality.
The purpose of this utility model is to solve magnetic field that eddy current that the gradient pulse induction by current produces produces influence and the eddy current of the gradient rise time problem that influences to magnetostatic field on head, provide a kind of simple in structure, make easily, can eliminate vortes interference, improve the device that eddy current is eliminated in the medical magnetic resonance imaging that is used for of picture quality.
The purpose of this utility model is achieved in that it comprises metallic laminations layer and insulating barrier, it is characterized in that described metallic laminations layer is at least two-layer, there is insulating barrier to be separated by between the adjacent metal lamination layer, the metallic laminations layer is rearranged by the metallic laminations bar, the metallic laminations bar forms by sheet metal is superimposed, and the metallic laminations bar in the adjacent metal lamination layer is and intersects the shape setting.
Because this utility model has adopted the lamellated structure of metallic laminations, and the metallic laminations bar in the adjacent metal lamination layer is intersected, it is placed between head and the gradient coil in use, it is separated by gradient coil and pole plate and leaves, when in gradient coil, having big pulse current to pass through, the faradic current of gradient coil directly acts on this device, stoped the effect of gradient magnetic to head, thereby solved magnetic field that eddy current that the gradient pulse induction by current produces produces influence and the eddy current of gradient rise time the problem that influences on head to magnetostatic field, shorten the gradient rise time, improved image quality.
In conjunction with the accompanying drawings and embodiments, this utility model is further described as follows:
Fig. 1 is one of structural representation of the present utility model
Fig. 2 is two of a structural representation of the present utility model
Fig. 3 is a metallic laminations bar structural representation of the present utility model
Fig. 4 is the structural representation that this utility model cooperates with MR imaging apparatus
With reference to accompanying drawing: this utility model comprises metallic laminations layer 1,3 and insulating barrier 2, described metallic laminations layer is at least two-layer, there is insulating barrier 2 to be separated by between the adjacent metal lamination layer 1,3, metallic laminations layer 1,3 is made of the metallic laminations bar 7 that is arranged parallel to each other, metallic laminations bar 7 is formed by identical sheet metal 701 bondings of shape, and the metallic laminations bar 7 in the adjacent metal lamination layer is and intersects the shape setting.The number of plies of metallic laminations layer is generally layer 2-4, be respectively equipped with insulating barrier 4 and insulating barrier 6 on the surface of metallic laminations 1,3, side at the metallic laminations layer also is provided with insulating barrier 5, bonding between the adjacent metal sheet 701 by insulating cement 201, sheet metal 701 employing pcrmeability height, the stalloy that remanent magnetism is few are made, its thickness is 0.1～0.4mm, and width is 8～12mm, and length is not less than 10mm.Metallic laminations layer 1,3 is in the form of annular discs.When eliminating device 8 uses of eddy current, it is installed in the MR imaging apparatus, MR imaging apparatus comprises column 12 and imaging space 19, is symmetrically arranged with gradient coil 11,15 successively in the both sides up and down of imaging space 19; Head 13,17; Magnetic 10,14; Pole plate 9,16, match with grading ring 20,18 in the outside of gradient coil 11,15, described gradient coil 11,15, head 13,17, magnetic 10,14 and pole plate 9,16 all join with column 12 and are close to mutually, the device 801 of eliminating eddy current is arranged between head 13 and the gradient coil 11, the device 802 of eliminating eddy current is arranged between head 17 and the gradient coil 15, column 12 is all made by metal material with head 13,17, and column 12 can constitute magnetic loop in use; Pole plate the 9, the 16th is made by metal material, has good permeability; Magnetic 10,14 is a permanent magnet material, and it can produce magnetostatic field; Gradient coil 11,15 is made by the metal copper material, and grading ring 18,20 is made by metal material, and it can carry out shimming to magnetostatic field.Because this device separates the pole plate of gradient coil and magnet, when applying gradient, be when having big pulse current to pass through in the gradient coil, the faradic current of gradient coil directly acts on this utility model, do not produce eddy current on the head, the rising of gradient is not subjected to the retardation of eddy current, thereby the gradient rise time is just fast.What this utility model adopted is the disc type layer structure, is insulating with insulant outside it and between two-layer, in order to avoid each interlayer forms eddy current loop.It not only can block the swirl channel of X, Y direction, and can eliminate the eddy current of Z direction, reaches the effect that improves picture quality.
Claims (4)
1, eliminates the device of eddy current in a kind of medical magnetic resonance imaging, comprise metallic laminations layer and insulating barrier, it is characterized in that described metallic laminations layer is at least two-layer, there is insulating barrier to be separated by between the adjacent metal lamination layer, the metallic laminations layer is rearranged by the metallic laminations bar, the metallic laminations bar forms by sheet metal is superimposed, and the metallic laminations bar in the adjacent metal lamination layer is and intersects the shape setting.
2, eliminate the device of eddy current in a kind of medical magnetic resonance imaging according to claim 1, the number of plies that it is characterized in that described metallic laminations layer is generally layer 2-4, surface at the metallic laminations layer is provided with insulating barrier, side at the metallic laminations layer also is provided with insulating barrier, and is bonding by insulating cement between the adjacent metal sheet.
3, eliminate the device of eddy current in a kind of medical magnetic resonance imaging according to claim 1, it is characterized in that described sheet metal adopts pcrmeability height, stalloy that remanent magnetism is few to make, its thickness is 0.1～0.4mm, and width is 8～12mm, and length is not less than 10mm.
4, eliminate the device of eddy current in a kind of medical magnetic resonance imaging according to claim 1, it is characterized in that described metallic laminations layer is in the form of annular discs.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 01245762 CN2481283Y (en) | 2001-06-06 | 2001-06-06 | Vortex eliminating device for medical nuclear magnetic resonance imaging |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 01245762 CN2481283Y (en) | 2001-06-06 | 2001-06-06 | Vortex eliminating device for medical nuclear magnetic resonance imaging |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2481283Y true CN2481283Y (en) | 2002-03-13 |
Family
ID=33656961
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 01245762 Expired - Fee Related CN2481283Y (en) | 2001-06-06 | 2001-06-06 | Vortex eliminating device for medical nuclear magnetic resonance imaging |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2481283Y (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2003082106A1 (en) * | 2002-04-01 | 2003-10-09 | Shenyang Neusoft Bopu Nmr Tech Co., Ltd. | A permanent magnet for magnet resonance |
| US7084632B2 (en) | 2002-04-01 | 2006-08-01 | Shenyang Neusoft Bopu Nmr Tech Co., Ltd. | Permanent magnet for magnet resonance |
| CN101256221B (en) * | 2007-02-28 | 2010-09-29 | 西门子（中国）有限公司 | Method for reducing eddy due to gradient magnetic field |
| CN104407314A (en) * | 2014-11-26 | 2015-03-11 | 江苏美时医疗技术有限公司 | Permanent magnet anti-eddy unit |
| CN106597334A (en) * | 2016-12-20 | 2017-04-26 | 国网重庆市电力公司电力科学研究院 | Unilateral nuclear magnetic resonance sensor and shielding structure of radio frequency coil |
| CN114267514A (en) * | 2021-11-29 | 2022-04-01 | 深圳航天科技创新研究院 | Streamlined magnet structure for magnetic resonance imaging |
-
2001
- 2001-06-06 CN CN 01245762 patent/CN2481283Y/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2003082106A1 (en) * | 2002-04-01 | 2003-10-09 | Shenyang Neusoft Bopu Nmr Tech Co., Ltd. | A permanent magnet for magnet resonance |
| US7084632B2 (en) | 2002-04-01 | 2006-08-01 | Shenyang Neusoft Bopu Nmr Tech Co., Ltd. | Permanent magnet for magnet resonance |
| CN101256221B (en) * | 2007-02-28 | 2010-09-29 | 西门子（中国）有限公司 | Method for reducing eddy due to gradient magnetic field |
| CN104407314A (en) * | 2014-11-26 | 2015-03-11 | 江苏美时医疗技术有限公司 | Permanent magnet anti-eddy unit |
| CN106597334A (en) * | 2016-12-20 | 2017-04-26 | 国网重庆市电力公司电力科学研究院 | Unilateral nuclear magnetic resonance sensor and shielding structure of radio frequency coil |
| CN114267514A (en) * | 2021-11-29 | 2022-04-01 | 深圳航天科技创新研究院 | Streamlined magnet structure for magnetic resonance imaging |
| CN114267514B (en) * | 2021-11-29 | 2023-11-14 | 深圳航天科技创新研究院 | Streamlined magnet structure for magnetic resonance imaging |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0691548B1 (en) | Magnetic field generating device for use in MRI | |
| EP0192331B1 (en) | Electromagnet | |
| JPH07163546A (en) | Magnetic resonance image forming device (mri) magnet | |
| WO1993018707A1 (en) | Magnetic field generator for mri | |
| US5252924A (en) | Magnetic field generating apparatus for MRI | |
| EP0984461B1 (en) | Low eddy current and low hysteresis magnet pole faces in MR imaging | |
| CN2481283Y (en) | Vortex eliminating device for medical nuclear magnetic resonance imaging | |
| TW511104B (en) | High performance bulk metal magnetic component | |
| JP2561591B2 (en) | Magnetic field generator for MRI | |
| JP3016544B2 (en) | Permanent magnet magnetic circuit | |
| CN1389177A (en) | Medical magnetic resonance system and its eddy current eliminator | |
| EP0801314A1 (en) | MRI magnet assembly with opposite permanent magnets | |
| CN201421769Y (en) | Magnetic valve type controllable reactor three-plunger non air-gap iron core | |
| JP2764458B2 (en) | Magnetic field generator for MRI | |
| US6809519B2 (en) | Inclined magnetic field generation coil and magnetic field generator for MRI | |
| US11423930B2 (en) | Hard disk drive with composite permanent magnet | |
| EP0541872A1 (en) | Magnetic field generating apparatus for MRI | |
| Tomida et al. | Application of fine-grained doubly oriented electrical steel to IPM synchronous motor | |
| US6937018B2 (en) | Systems and methods for fabricating pole pieces for magnetic resonance imaging systems | |
| CN1284293C (en) | Permanent magnet magnetic resistance straight line motor | |
| CN221262106U (en) | Magnetic integrated inductive magnet and inductor | |
| JP3445303B2 (en) | Magnetic field generator for MRI | |
| JP3073933B2 (en) | Magnetic field generator for MRI | |
| JPH04138131A (en) | Magnetic field generation device for mri | |
| JP2004065714A (en) | Magnetic field generating device for magnetic resonance imaging |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |