CN1375705A - Eddy current reducing device for magnetic resonant imaging equipment - Google Patents
Eddy current reducing device for magnetic resonant imaging equipment Download PDFInfo
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- CN1375705A CN1375705A CN 02115759 CN02115759A CN1375705A CN 1375705 A CN1375705 A CN 1375705A CN 02115759 CN02115759 CN 02115759 CN 02115759 A CN02115759 A CN 02115759A CN 1375705 A CN1375705 A CN 1375705A
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- insulating material
- lamination body
- iron sheet
- pole shoe
- silicon iron
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Abstract
The vortex-reducing device in the magnetic resonance imaging equipment is characterized by that: soaking the orientationless silicon iron sheets in resin paint, then sticking them into square laminated body, sticking the laminated body on the pole shoe, using insulating material to retain insulation between the laminated bodies, between laminated body and pole shoe and between the laminated body and uniform field ring, making the laminated body into the form similar to pole shoe, and sticking second layer of insulating material and laminated body on first layer of laminated body, two layers of laminated bodies are pperpendicular and more sticking insulating material on the second layer of laminated body. Said invention can raise dimage resolution of said imaging equipment.
Description
Technical field:
The present invention relates to magnetic resonance imaging (hereinafter to be referred as MRI) device, more specifically relate to the minimizing vortex device of MRI.This reduces the homogeneity in vortex device protection Magnatic Resonance Imaging (MRI) apparatus magnetic field, to improve the sharpness of MRI device imaging.
Background technology:
The basic demand of magnetic resonance imaging (MRI) device is fast-changing gradient magnetic of stack on a uniform static magnetic field, positional information correspondence in the imaging body is provided NMR signal, obtain image by a series of accurate pulsed gradient magnetic field.Two yokes of general Magnatic Resonance Imaging (MRI) apparatus permanent magnet are connected by two root posts, form the detection zone of an opening, magnet steel adopts neodymium-iron-boron magnetic material, cement on the yoke with seccotine, constitute magnetic loop by two root posts, pole shoe is fastened on the magnet steel, a grading ring is arranged on the pole shoe, the effect of grading ring is to make the magnetic field of detection zone more even, and in the middle of pole shoe, bank goes into to reduce vortex device.Because the specific (special) requirements of MRI device, gradient coil must be contained near the pole shoe in magnetic field, when the excitation of gradient coil at the fast-pulse electric current, very fast variation also takes place in the gradient magnetic that produces, produce eddy current near the pole shoe that this variation causes making with iron the gradient coil, pole shoe will be destroyed the homogeneity of the static magnetic field of MRI equipment by near the magnetic field magnetisation that is produced the gradient coil.Eddy current influences the shape of the square wave in the magnetic field that gradient coil produces conversely, strengthen gradient pulse and reached time of predetermined magnetic field strength, and make between adjacent two gradient pulses gradient magnetic intensity can not return to zero, directly influenced the bearing accuracy of imaging, made the sharpness of MRI imaging be subjected to influence.
For addressing the above problem, must manage to reduce the electric conductivity of pole shoe material, in No. 4827235 patent of the U.S., utilize non-conducting material, promptly amorphous metal potpourri or compound substance are made pole shoe, though this method has shortened pulse rise time, its weak point is the material price costliness, and under the high-intensity magnetic field condition, therefore the magnetoconductivity of this material can satisfy and close, reduce, this has greatly hindered its application in high field intensity MRI device.Japanese patent application publication No. CN 1116312A then adopts siliconized plate space-oriented direction lamination, its weak point is, because silicon iron sheet has bigger coercive force, the matrix of certain area of its formation, remarkable inadequately to preventing that remanent magnetism from destroying the inhomogeneity effect of space magnetic field.
Summary of the invention:
The purpose of this invention is to provide the minimizing vortex device in a kind of Magnatic Resonance Imaging (MRI) apparatus, this minimizing vortex device is drawn materials easily, low price, and not influencing substantially under the prerequisite of MRI device magnetic field homogeneity, the eddy current that can significantly reduce gradient magnetic and produced.
In order to achieve the above object, the present invention adopts following technical scheme: owing to reduce vortex device is a part of permanent magnet in the Magnatic Resonance Imaging (MRI) apparatus, therefore, the permanent magnet of Magnatic Resonance Imaging (MRI) apparatus is described earlier here, two yokes in the permanent magnet are to be connected by two root posts, form the detection zone of an opening, magnet steel adopts neodymium-iron-boron magnetic material, cement on the yoke with seccotine, constitute magnetic loop by two root posts, pole shoe is fastened on the magnet steel, a grading ring is arranged on the pole shoe, on pole shoe, the centre of grading ring, bank goes into to reduce vortex device.
Minimizing vortex device in a kind of Magnatic Resonance Imaging (MRI) apparatus of the present invention, insulating material sticks with glue on pole shoe earlier, to there be oriented silicon iron sheet resin pickup lacquer, with glue the bonding squarely lamination of the silicon iron sheet body behind the resin pickup lacquer, on the gluing insulating material that is connected on the pole shoe of lamination body and function, silicon iron sheet is arranged along the static magnetic field magnetic line of force direction of permanent magnet in the lamination body, the orientation of silicon iron sheet is orthogonal between the lamination body, and make it keep each other insulation with insulating material, exceed pole shoe shape and partly remove being bonded in lamination body on the insulating material, be processed into identical with pole shoe shape, and between lamination body and grading ring, separate with insulating material, on the lamination body, paste second layer insulating material and lamination body by above-mentioned again with quadrat method, but the silicon iron sheet quadrature in second layer lamination body and the first cascade lamellar body is pasted insulating material again on second layer lamination body.
Its thickness of above-mentioned silicon iron sheet is 0.2～0.5 millimeter, is shaped as 5～14 millimeters * 60～100 millimeters rectangle.
Above-mentioned insulating material usable resins, film or hardwood.
Above-mentioned glue available epoxy or anaerobic adhesive.
Above-mentioned lacquer usable resins lacquer.
The present invention compared with prior art, have the following advantages: make the common material of electrician's transformer because the silicon iron sheet that is adopted is a kind of being widely used, can buy from the market easily, and it is cheap, this is very favourable to reducing production costs, simultaneously silicon iron sheet has higher full magnetic flow density, is being used for the pole shoe of high field intensity, can therefore not lose magnetic flux and increases the size of pole shoe and increase cost.Because special construction of the present invention, the laminate single-sheet thickness is below 0.5mm, and perpendicular to pole-shoe face, this silicon iron sheet area that allows to generate remanent magnetism has reduced hundreds of times, greatly reduced the living space of remanent magnetism, thereby accelerated the rise time of gradient pulse, stoped the interference of gradient magnetic, improved the imaging resolution of Magnatic Resonance Imaging (MRI) apparatus static magnetic field.
Description of drawings:
Fig. 1 is the structural representation of Magnatic Resonance Imaging (MRI) apparatus permanent magnet.
Fig. 2 is for reducing the structural representation of vortex device.
Fig. 3 is for reducing the cut-open view of vortex device.
Below in conjunction with accompanying drawing, the specific embodiment of the present invention is further described.
According to Fig. 1 as can be known, two yoke 1-1 ' of Magnatic Resonance Imaging (MRI) apparatus permanent magnet are connected by two root post 6-6 ', form the detection zone 7 of an opening, magnet steel 2-2 ' adopts neodymium-iron-boron magnetic material, cement on the yoke 1-1 ' with seccotine, constitute magnetic loop by column 6-6 ', pole plate 3-3 ' is fastened on the magnet steel 2-2 ', a grading ring 5-5 ' is arranged on the pole plate 3-3 ', and the effect of grading ring is to make the magnetic field of detection zone 7 more even.In the middle of pole plate, bank goes into to reduce vortex device 4-4 ', and this compensator can be eliminated the harmful effect that image quality is brought owing to the eddy effect that high-power gradient current produced.
According to Fig. 2 as can be known, the square lamination body 4 that reduces vortex device is 0.2～0.5 millimeter of a thickness, after being shaped as 5～14 millimeters * 60～100 millimeters rectangular no oriented silicon iron sheet resin pickup lacquers, with epoxy resin or the bonding one-tenth of anaerobic adhesive, silicon iron sheet is arranged along the static magnetic field magnetic line of force direction of permanent magnet in the lamination body, the orientation of silicon iron sheet is orthogonal between the lamination body, and with insulating material 8 resins, film, hardwood makes it keep insulation each other, be processed into the lamination body 4 that is bonded on the insulating material identical with pole shoe shape, and between lamination body 4 and grading ring 5, separate insulating material 8 usable resins with insulating material 8, film, hardwood.
According to Fig. 3 as can be known, reduce vortex device and on pole shoe 3, be stained with subsides insulating material 8 earlier with epoxy resin or anaerobic adhesive, insulating material usable resins, film or hardwood, then lamination body 4 usefulness epoxy resin or anaerobic adhesive are bonded on the insulating material 8 on the pole shoe 3, silicon iron sheet is arranged along the static magnetic field magnetic line of force direction of permanent magnet in the lamination body, the orientation of silicon iron sheet is orthogonal between the lamination body, and make it keep each other insulation with resin, film, hardwood, and between lamination body and grading ring, separate 8, insulating material 8 usable resins, film, hardwood with insulating material; On first cascade lamellar body 4, be stained with subsides insulating material 8 again with epoxy resin or anaerobic adhesive, insulating material 8 usable resins, film or hardwood, on insulating material 8, paste second layer lamination body 4 again, second layer lamination body 4 and first cascade lamellar body 4 quadratures, on second layer lamination body 4, paste insulating material 8 again, separate with insulating material 8 resins, film, hardwood between lamination body 4 and the grading ring 5, make to keep insulation between them with epoxy resin or anaerobic adhesive.
Embodiment:
Minimizing vortex device of the present invention is stained with the subsides insulating material with epoxy resin or anaerobic adhesive earlier on pole shoe, the insulating material usable resins, film or hardwood, then with 0.2～0.5 millimeter of thickness, be shaped as 5～14 millimeters * 60～100 millimeters rectangular no oriented silicon iron sheet resin pickup lacquers, with epoxy resin or the anaerobic adhesive bonding squarely lamination of the silicon iron sheet body after the resin pickup lacquer, lamination body and function epoxy resin or anaerobic adhesive are bonded on the insulating material on the pole shoe, silicon iron sheet is arranged along the static magnetic field magnetic line of force direction of permanent magnet in the lamination body, the orientation of silicon iron sheet is orthogonal between the lamination body, and use resin, film, hardwood makes it keep insulation each other, be processed into the lamination body that is bonded on the insulating material identical with pole shoe shape, and between lamination body and grading ring, separate the insulating material usable resins with insulating material, film, hardwood.On the lamination body, paste second layer insulating material and lamination body by above-mentioned again with quadrat method, different layer 2-only and the silicon iron sheet quadrature in the first cascade lamellar body.Promptly on the ground floor silicon iron sheet, be stained with the subsides insulating material with epoxy resin or anaerobic adhesive, insulating material usable resins, film or hardwood, then with 0.2～0.5 millimeter of thickness, be shaped as 5～14 millimeters * 60～100 millimeters rectangular no oriented silicon iron sheet resin pickup lacquers, the bonding squarely lamination of the silicon iron sheet body after with epoxy resin or anaerobic adhesive resin pickup being coated with lacquer.Lamination body and function epoxy resin or anaerobic adhesive are bonded on the insulating material on the pole shoe, and silicon iron sheet is arranged along the static magnetic field magnetic line of force direction of permanent magnet in the lamination body.The orientation of silicon iron sheet is orthogonal between the lamination body, and make it keep each other insulation with resin, film, hardwood, be processed into the lamination body that is bonded on the insulating material identical with pole shoe shape, and between lamination body and grading ring, separate insulating material usable resins, film, hardwood with insulating material.On second layer lamination body, paste insulating material resin, film, hardwood again.
Claims (5)
1, minimizing vortex device in a kind of Magnatic Resonance Imaging (MRI) apparatus, it is characterized in that, the first insulating material (8) that on pole shoe (3), sticks with glue of this minimizing vortex device, to there be oriented silicon iron sheet resin pickup lacquer, with glue the bonding squarely lamination of the silicon iron sheet body (4) behind the resin pickup lacquer, lamination body (4) sticks with glue on the insulating material (8) that is connected on the pole shoe, silicon iron sheet is arranged along the static magnetic field magnetic line of force direction of permanent magnet in the lamination body (4), the orientation of silicon iron sheet is orthogonal between the lamination body, and make it keep each other insulation with insulating material, exceed pole shoe shape and partly remove being bonded in lamination body on the insulating material, be processed into identical with pole shoe shape, and between lamination body and grading ring, separate with insulating material, on the lamination body, paste second layer insulating material and lamination body by above-mentioned again with quadrat method, but the silicon iron sheet quadrature in second layer lamination body and the first cascade lamellar body is pasted insulating material again on second layer lamination body.
2, the minimizing vortex device in a kind of Magnatic Resonance Imaging (MRI) apparatus according to claim 1 is characterized in that, its thickness of described silicon iron sheet is 0.2～0.5 millimeter, is shaped as 5～14 millimeters * 60～100 millimeters rectangle.
3, the minimizing vortex device in a kind of Magnatic Resonance Imaging (MRI) apparatus according to claim 1 is characterized in that, described insulating material (8) usable resins, film or hardwood.
4, the minimizing vortex device in a kind of Magnatic Resonance Imaging (MRI) apparatus according to claim 1 is characterized in that, described glue available epoxy or anaerobic adhesive.
5, the minimizing vortex device in a kind of Magnatic Resonance Imaging (MRI) apparatus according to claim 1 is characterized in that, described lacquer usable resins lacquer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021157596A CN1159597C (en) | 2002-04-26 | 2002-04-26 | Eddy current reducing device for magnetic resonant imaging equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021157596A CN1159597C (en) | 2002-04-26 | 2002-04-26 | Eddy current reducing device for magnetic resonant imaging equipment |
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| Publication Number | Publication Date |
|---|---|
| CN1375705A true CN1375705A (en) | 2002-10-23 |
| CN1159597C CN1159597C (en) | 2004-07-28 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB021157596A Expired - Fee Related CN1159597C (en) | 2002-04-26 | 2002-04-26 | Eddy current reducing device for magnetic resonant imaging equipment |
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| CN (1) | CN1159597C (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1926443B (en) * | 2004-03-03 | 2010-09-01 | 皇家飞利浦电子股份有限公司 | Magnetic resonance imaging scanner with booster iron |
| 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 |
-
2002
- 2002-04-26 CN CNB021157596A patent/CN1159597C/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1926443B (en) * | 2004-03-03 | 2010-09-01 | 皇家飞利浦电子股份有限公司 | Magnetic resonance imaging scanner with booster iron |
| 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 |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1159597C (en) | 2004-07-28 |
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Granted publication date: 20040728 Termination date: 20130426 |