CN203982939U - For magnet apparatus and the measurement mechanism thereof of magnetic resonance imaging - Google Patents
For magnet apparatus and the measurement mechanism thereof of magnetic resonance imaging Download PDFInfo
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- CN203982939U CN203982939U CN201420310314.7U CN201420310314U CN203982939U CN 203982939 U CN203982939 U CN 203982939U CN 201420310314 U CN201420310314 U CN 201420310314U CN 203982939 U CN203982939 U CN 203982939U
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Abstract
The utility model provides a kind of magnet apparatus for magnetic resonance imaging and measurement mechanism thereof, described magnet apparatus is included in the upper yoke and the lower yoke that in Z-direction, face with each other, on described upper yoke and described lower yoke, be sequentially with respectively permanent magnetic material, pole plate and grading ring, grading ring is configured to around pole plate, thereby is formed with magnetic field between two pole plates.Each in permanent magnetic material, pole plate and grading ring is configured to have non-circular symmetric shape, thereby forms the magnetic field homogeneity range with symmetric shape between two pole plates, and wherein Z-direction is the direction perpendicular to pole plate.The utility model also provides measurement mechanism simultaneously, for measuring according to the magnetic flux density of described magnet apparatus.Use the utility model, reduced cost, volume and the weight of magnet apparatus, and provide the foundation for the application of magnetic resonance is extended to Whole Body health check-up from Divisional diagnosis.
Description
Technical field
The utility model relates to medical instruments field, relates in particular to a kind of for the magnet apparatus of magnetic resonance imaging with for measuring the measurement mechanism of magnetic flux density of this magnet apparatus.
Background technology
Magnetic resonance imaging (MRI) equipment is one of greatest utility model in last century, almost can be used for the scanning at each position of human body, and human body is not had to ionization radiation injury, and soft tissue structure's clear display, can be used for whole body each position medical diagnosis on disease.
Magnet is a core component in MRI equipment, for generation of the necessary main field of magnetic resonance imaging.The magnet using in clinical magnetic resonance imaging equipment at present has three kinds: permanent-magnet, resistive magnet, superconducting magnet.Wherein permanent-magnet operation and maintenance cost are low, and manufacturing cost is also relatively low, and China has an abundant rare earth permanent magnet magnetic material, and China has resources advantage on permanent magnet type magnetic resonance, and permanent magnet type magnetic resonance is a main development direction of Chinese magnetic resonance.
Permanent-magnet is mainly made up of several major parts such as yoke, magnetic material, pole plate, grading rings.A very crucial index of permanent-magnet is uniformity of magnetic field.The principle of magnetic resonance imaging has determined to require the uniformity of magnetic field of imaging area very high, conventionally requires the inhomogeneities of imaging region intrinsic inductance to be less than tens even several ppm, and ppm represents 1,000,000/.Existing permanent-magnet has Double-pillar magnet, C type magnet etc., as shown in Figure 1.Magnetic material 2, pole plate 3 and the grading ring 4 of this magnet is all circle symmetric shape, correspondingly between two pole plates 3, form the magnetic field homogeneity range of a round symmetric shape, this homogeneity range is the spheroid-like (X=Y of the degeneration that two axles are equal, Z<X), the advantage of design is simple, convenient like this.
Permanent magnet type magnetic resonance imaging system when scanning system and the relativeness of human body as shown in Figure 2, the scanning direction that wherein Y direction is magnet, X-direction is parallel to pole plate and perpendicular to Y direction, Z-direction is the direction perpendicular to pole plate.But due to organization of human body feature (being similar to elongated cylindrical), particularly in the time using body coil to carry out body and centrum imaging, demand to Y direction areas imaging is larger than X-direction and Z-direction, therefore, in existing magnet apparatus, magnetic material, grading ring diameter all design becomes the demand that meets Y direction, waste with regard to some space in X-direction like this, thereby wasted magnet material, and and then increased cost.
For imaging device, the property uniformity in magnetic field requires high, and therefore most of Medical Devices are all to adopt circular magnet apparatus.If alteration of form, is difficult to obtain the magnetic field of high evenness.
Utility model content
In order to overcome existing defect, the utility model proposes a kind of for the magnet apparatus of magnetic resonance imaging with for measuring the measurement mechanism of magnetic flux density of this magnet apparatus.
According to an aspect of the present utility model, a kind of magnet apparatus for magnetic resonance imaging has been proposed, be included in the upper yoke and the lower yoke that in Z-direction, face with each other, on described upper yoke and described lower yoke, be sequentially with respectively permanent magnetic material, pole plate and grading ring, grading ring is configured to around pole plate, thereby be formed with magnetic field between two pole plates, described Z-direction is the direction perpendicular to pole plate, it is characterized in that: permanent magnetic material, each in pole plate and grading ring is configured to have non-round symmetric shape, thereby between two pole plates, form the magnetic field homogeneity range with symmetric shape.。
According on the other hand of the present utility model, a kind of measurement mechanism is provided, described measurement mechanism is for measuring the magnetic flux density of above-mentioned magnet apparatus, it is characterized in that, described measurement mechanism comprises: probe fixed head, described probe fixed head is vertically arranged between two pole plates, and can rotate with respect to pole plate, and probe fixed head is provided with the multiple fixing holes for static probe; Pole plate connector, described pole plate connector is arranged on pole plate and has draw-in groove; And rotating shaft, one end of described rotating shaft is connected to probe fixed head, and the other end of described rotating shaft can be rotatably set in draw-in groove and can in draw-in groove, move.
The utility model is according to the feature of organization of human body, magnet material, pole plate and grading ring are designed to non-round symmetric shape, and magnetic field is even, requirement can meet magnetic resonance imaging time, cost, volume and the weight of magnet apparatus are reduced again, meanwhile, also for being extended to Whole Body health check-up from Divisional diagnosis, the application of magnetic resonance provides the foundation.
Brief description of the drawings
Above-mentioned and other aspect of the present utility model and feature are by from presenting the explanation of embodiment is clear below in conjunction with accompanying drawing, wherein:
Fig. 1 is traditional permanent-magnet device schematic diagram;
Fig. 2 is Permanent Magnet MRI imaging schematic diagram;
Fig. 3 is according to the end view of the magnet apparatus of the utility model embodiment;
Fig. 4 is according to the schematic perspective view of the magnet apparatus of the utility model embodiment;
Fig. 5 is the schematic diagram of the magnetic field homogeneity range of magnet apparatus;
Fig. 6 (a)-(c) is front view, left view and the vertical view of magnet apparatus of the present utility model uniform magnetic field region;
Fig. 7 is that magnetic material is arranged vertical view, and intermediate magnetic material is orientated along Z axis, and paripheral zone dash area is that periphery magnetic material and orientation become 20 ° of angles with Z axis;
Fig. 8 is the software analysis result schematic diagram of intermediate magnetic material and periphery magnetic material;
Fig. 9 is for measuring the schematic perspective view of measurement mechanism of magnetic flux density of magnet apparatus according to of the present utility model; And
Figure 10 shows the pole plate connector of measurement mechanism of the present utility model and the schematic perspective view of rotating shaft.
Embodiment
The measurement mechanism of the magnetic flux density below in conjunction with the drawings and specific embodiments to magnet apparatus of the present utility model and this magnet apparatus of measurement is described in detail.
Fig. 3 is according to the end view of the magnet apparatus of the utility model embodiment.Be used for magnetic resonance imaging according to magnet apparatus of the present utility model, this magnet apparatus is included in the upper yoke 5 and the lower yoke that in Z-direction, face with each other, on described upper yoke and described lower yoke, be sequentially with respectively permanent magnetic material 6, pole plate 7 and grading ring 8, described grading ring 8 is configured to around pole plate 7, thereby is formed with magnetic field between two pole plates.Each in permanent magnetic material 6, pole plate 7 and grading ring 8 is configured to have non-circular symmetric shape, thereby forms the magnetic field homogeneity range 9 with symmetric shape between two pole plates.At this, described Z-direction is the direction perpendicular to pole plate, referring to Fig. 2.Because magnet apparatus has upper and lower symmetrical structure, therefore, only indicate in the drawings the building block on top at this, and bottom building block will no longer indicate with Reference numeral.
Because organization of human body feature (is similar to elliptical cylinder-shape, as shown in Figure 2), particularly in the time using body coil to carry out body and centrum imaging, demand to Y direction areas imaging is larger than X-direction, Z-direction, existing magnet is designed to magnetic material, grading ring diameter can meet the demand of Y direction, waste with regard to some space in X-direction like this, magnet cost is corresponding increase also.
For this reason, in magnet apparatus of the present utility model, the size that the size of non-round symmetric shape is configured in Y direction is greater than the size in X-direction, and the size in X-direction is greater than the distance of two pole plates in Z-direction, as shown in Fig. 6 (a)-6 (c).As previously mentioned, referring to Fig. 2, the scanning direction that Y direction is magnet apparatus, X-direction is parallel to pole plate and perpendicular to Y direction.Requirement to the different size in X-direction and Y direction when magnet apparatus of the present utility model can meet magnetic resonance imaging by having this non-round symmetric shape, can reduce again unnecessary waste, thereby reduces cost, the volume and weight of magnet.This more meets human body demands on examination, provides the foundation for the application of magnetic resonance is extended to Whole Body health check-up from Divisional diagnosis.
According to an example, for example, the size in size, Y direction in X-direction and two pole plates distance on Z axis has the ratio of 1:1.1:0.8.This ratio is only illustrative, and magnet apparatus of the present utility model is not limited to this size.
Further, the principle of magnetic resonance imaging has determined to require the uniformity of magnetic field of imaging area very high, conventionally require the inhomogeneities of imaging region intrinsic inductance to be less than tens even several ppm, equate in the magnetic field intensity at Ye Nenghe center, edge in order to ensure magnetic devices, permanent magnetic material 6 comprises intermediate magnetic material 61 and periphery magnetic material 62 (participation Fig. 3).The magnetizing direction of intermediate magnetic material 61 is parallel to Z-direction, and magnetizing direction and the Z-direction of periphery magnetic material 62 are angled.
Preferably, the magnetizing direction of periphery magnetic material 62 and Z-direction form 20 ° of angles.This angle is only exemplary, and the angle that periphery magnetic material and Z-direction form is not limited to this.In addition, according to a preferred embodiment, intermediate magnetic material 61 is 1:0.65 with weight ratio or the volume ratio of periphery magnetic material 62.
In order to obtain the magnetic field homogeneity range according to magnet apparatus of the present utility model, in the time of design, first determine magnetic induction density B 0 and the scope of magnetic field homogeneous area according to imaging demand.Then, set thickness and the magnetizing direction of major and minor axis, magnetizing direction and the periphery magnetic material of the intermediate magnetic material of permanent-magnet.Magnetic material can be chosen as required, then be made into threedimensional model and this threedimensional model is input in electromagnetic software, such as Ansoft Maxwell or Ansys, Amperes etc., become the Z-direction magnetic flux density of intersection to analyze imaging region outer surface with XZ, YZ planar shaped.In areas imaging Z direction magnetic flux density a little must, within B0 × (1 ± 0.5%), Figure 8 shows that software analysis result schematic diagram.
Magnetic material consumption increases or the trade mark raising of magnetic material can improve field intensity, regulates thickness and the magnetizing direction of periphery magnetic material to regulate uniformity of magnetic field, and these two aspects also can influence each other.Can obtain by comparing calculation repeatedly the permanent-magnet that a magnetic field intensity and magnetic field homogeneity all conform to a predetermined condition.
Concrete example explanation below, a kind of magnetic field intensity is the magnet apparatus of 0.3T, as shown in Figure 3 and Figure 7, its overall dimension is long 1664mm, wide 1530mm, high 1260mm, two yoke spacing are 773mm, grading ring spacing 410mm, magnetic material thickness 90mm, the oval major axis of magnetic material is long is 1404mm, and minor axis is long is 1276m.The magnetic material trade mark is chosen N47, Br>14.0KGs, Hcj>12.5KOe, center magnet major axis is 1074mm, minor axis is 946mm, and magnetic direction is along Z direction, and external magnets thickness is 135mm, magnetic direction becomes 20 degree angles with Z axis, intermediate magnetic material is 1:0.65 with periphery magnetic material than (weight or volume ratio).
The magnetic field homogeneity range scope of this magnet apparatus is 420*500*380mm (X*Y*Z).Compare the homogeneity range scope of plain edition magnet 500*500*380mm (X*Y*Z), although diminish in X-direction, but can meet the demand of body scans completely, magnetic material is saved 315kg, weight saving 8.6t, the size reduction 128mm of X-direction, cost reduction 480,000, as shown in the table.
Traditional magnet imaging area is a round symmetrical region, the uniformity that it is carried out to field is measured and can be utilized circular symmetry to design survey tool, and magnet of the present utility model imaging area is a non-round symmetric shape, it is carried out to field uniformity measurement will be more complex.For more effectively magnet performance being measured, the utility model proposes a kind of measurement mechanism, be used for measuring the magnetic flux density of the symmetrical magnet apparatus of non-circle.
As shown in Figure 9 and Figure 10, according to an embodiment of the present utility model, measurement mechanism of the present utility model comprises probe fixed head 10, pole plate connector 11 and rotating shaft 12.Probe fixed head 10 is vertically arranged between two pole plates 7, and can rotate with respect to pole plate 7.Probe fixed head 10 is provided with the multiple fixing holes 13 for static probe, and the diverse location place of described multiple fixed hole positions on probe fixed head, so that removable probe is tested the magnetic flux density of the diverse location in Z-direction.Pole plate connector 11 is arranged on pole plate and has draw-in groove 14.One end of rotating shaft 12 is connected to probe fixed head 10, and the other end of rotating shaft can be rotatably set in draw-in groove 14 and can in draw-in groove 14, move.For example, referring to Figure 10, have two pivot O1 and O2 in draw-in groove 14, rotating shaft 12 can move to another pivot from a pivot.
In order to make test position accurate, pole plate 7 is provided with multiple location holes 15.Measurement mechanism of the present utility model also comprises fixed head keeper 16, and described fixed head keeper comprises the fixed head connector being connected in location hole 15 and is arranged on the elastic ring (not shown) of the side of fixed head keeper.According to an embodiment, fixed head connector can be alignment pin 17 (as shown in Figure 9).The location hole that utilizes alignment pin to enter on pole plate plays positioning action.In the time rotating probe fixed head, promote alignment pin and move up, alignment pin shifts out location hole.In the time that fixed head moves to next location hole, due to the effect of fixed head keeper side elastic ring, alignment pin enters next location hole, plays the effect of probe fixed head anglec of rotation precise positioning.But fixed head connector is not limited to this, and can be for being arranged in location hole for fixing any securing member.
Although exemplary embodiments of the present utility model is illustrated, but obviously it will be appreciated by those skilled in the art that, in the situation that not deviating from spirit of the present utility model and principle, can change, its scope claims with and equivalent in limit.
Claims (9)
1. the magnet apparatus for magnetic resonance imaging, be included in the upper yoke and the lower yoke that in Z-direction, face with each other, on described upper yoke and described lower yoke, be sequentially with respectively permanent magnetic material, pole plate and grading ring, described grading ring is configured to around described pole plate, thereby be formed with magnetic field between two described pole plates, described Z-direction is the direction perpendicular to described pole plate, it is characterized in that:
Each in described permanent magnetic material, described pole plate and described grading ring is configured to have non-circular symmetric shape, thereby forms the magnetic field homogeneity range with symmetric shape between two described pole plates.
2. magnet apparatus according to claim 1, is characterized in that:
The size of described non-circular symmetric shape is configured such that the size in Y direction is greater than the size in X-direction, and the size in described X-direction is greater than the distance in described Z-direction between two described pole plates; And
Described Y direction is the scanning direction of described magnet apparatus, and described X-direction is parallel to described pole plate and perpendicular to described Y direction.
3. magnet apparatus according to claim 2, is characterized in that, the described distance between full-size and two described pole plates in full-size, described Y direction in described X-direction has the ratio of 1:1.1:0.8.
4. magnet apparatus according to claim 1, it is characterized in that, described permanent magnetic material comprises intermediate magnetic material and periphery magnetic material, and the magnetizing direction of described intermediate magnetic material is parallel to described Z-direction, and the magnetizing direction of described periphery magnetic material and described Z-direction are angled.
5. magnet apparatus according to claim 4, is characterized in that, the weight ratio of described intermediate magnetic material and described periphery magnetic material or volume ratio are 1:0.65.
6. magnet apparatus according to claim 4, is characterized in that, the magnetizing direction of described periphery magnetic material and described Z-direction form 20 ° of angles.
7. a measurement mechanism, described measurement mechanism is used for measuring the magnetic flux density of magnet apparatus according to claim 1, it is characterized in that, and described measurement mechanism comprises:
Probe fixed head, described probe fixed head is vertically arranged between two described pole plates, and can be with respect to described pole plate rotation, and described probe fixed head is provided with the multiple fixing holes for static probe;
Pole plate connector, described pole plate connector is arranged on described pole plate and has draw-in groove; With
Rotating shaft, one end of described rotating shaft is connected to described probe fixed head, and the other end of described rotating shaft can be arranged on rotatably in described draw-in groove and can in described draw-in groove, move.
8. measurement mechanism according to claim 7, is characterized in that:
Described pole plate is provided with multiple location holes; And
Described measurement mechanism also comprises fixed head keeper, and described fixed head keeper comprises the fixed head connector being connected in described location hole and is arranged on the elastic ring of the side of described fixed head keeper.
9. measurement mechanism according to claim 8, is characterized in that, described fixed head connector comprises alignment pin.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420310314.7U CN203982939U (en) | 2014-06-12 | 2014-06-12 | For magnet apparatus and the measurement mechanism thereof of magnetic resonance imaging |
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| CN201420310314.7U CN203982939U (en) | 2014-06-12 | 2014-06-12 | For magnet apparatus and the measurement mechanism thereof of magnetic resonance imaging |
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| CN203982939U true CN203982939U (en) | 2014-12-03 |
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| CN201420310314.7U Withdrawn - After Issue CN203982939U (en) | 2014-06-12 | 2014-06-12 | For magnet apparatus and the measurement mechanism thereof of magnetic resonance imaging |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104051122A (en) * | 2014-06-12 | 2014-09-17 | 包头市稀宝博为医疗系统有限公司 | Magnet device used for magnetic resonance imaging and measuring equipment of magnet device |
| CN111896900A (en) * | 2020-07-06 | 2020-11-06 | 苏州佳祺仕信息科技有限公司 | Multi-probe Gaussian detection device |
-
2014
- 2014-06-12 CN CN201420310314.7U patent/CN203982939U/en not_active Withdrawn - After Issue
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104051122A (en) * | 2014-06-12 | 2014-09-17 | 包头市稀宝博为医疗系统有限公司 | Magnet device used for magnetic resonance imaging and measuring equipment of magnet device |
| CN111896900A (en) * | 2020-07-06 | 2020-11-06 | 苏州佳祺仕信息科技有限公司 | Multi-probe Gaussian detection device |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20141203 Effective date of abandoning: 20160824 |
|
| C25 | Abandonment of patent right or utility model to avoid double patenting |