CN214897870U

CN214897870U - Superconducting magnet assembly and magnetic resonance equipment

Info

Publication number: CN214897870U
Application number: CN202120547987.4U
Authority: CN
Inventors: 刘曙光; 樊曼; 杨绩文; 高媛; 王利锋; 汪涛
Original assignee: Shanghai United Imaging Healthcare Co Ltd
Current assignee: Shanghai United Imaging Healthcare Co Ltd
Priority date: 2021-03-17
Filing date: 2021-03-17
Publication date: 2021-11-26
Anticipated expiration: 2031-03-17

Abstract

The present application relates to a superconducting magnet assembly and a magnetic resonance apparatus. The superconducting magnet assembly includes: a cryostat; a main magnet disposed within the cryostat, the main magnet including a main coil and a main coil former for supporting the main coil; a shim coil disposed within the cryostat, the shim coil comprising a plurality of saddle coils with at least one saddle coil disposed outside of the main magnet. The superconducting magnet assembly comprises a plurality of saddle-shaped coil shimming coils, and can simultaneously perform first-order shimming, second-order shimming and higher-order shimming on a main magnetic field generated by a main magnet; the saddle coil is arranged outside the main magnet and inside the cryostat, instead of inside the detection aperture formed around the main magnet, without causing a shortening of the detection aperture.

Description

Superconducting magnet assembly and magnetic resonance equipment

Technical Field

The application relates to the technical field of medical imaging equipment, in particular to a superconducting magnet assembly and magnetic resonance equipment.

Background

The magnetic resonance scanning system utilizes hydrogen atoms which are in Larmor precession in a uniform main magnetic field to generate a magnetic resonance phenomenon under the excitation of a radio frequency field, and realizes magnetic resonance imaging by using spatial coding positioning of a gradient field. The strength and the uniformity of a main magnetic field of the superconducting magnet are important indexes for measuring the performance of the superconducting magnet, and therefore the use performance of the magnetic resonance equipment is guaranteed. However, additional shimming is usually required because the manufacturing installation and the low temperature shrinkage errors make it impossible for the homogeneity of the bare magnetic field to reach the desired value of the theoretical design.

The shimming operation in the prior art mainly comprises two shimming methods: passive shimming and active shimming. The method of passive shimming (also called passive shimming) is that soft magnetic material with high saturation and high magnetic conductivity, such as silicon steel, is used as a shimming sheet, is arranged in a support box, and is axially arranged in a shimming groove between a gradient coil and a magnet along a Z axis to correct the uniformity of a main magnetic field to a certain degree. Passive shimming works well for shimming higher-order terms, but if the homogeneity of the naked magnetic field is poor, many shimming pieces are needed for shimming. Because numerous shimming pieces have higher magnetization intensity and can generate very large acting force in strong magnetic field gradient movement, the shimming pieces are difficult to insert and pull in the field, the inserted and pull shimming pieces can only be installed after demagnetization, repeated test calculation installation needs a plurality of times of excitation demagnetization, a lot of expensive liquid helium can be consumed, time and labor are consumed, and the numerous shimming pieces can generate larger eddy current heat effect under the condition of gradient field work, so that the image quality is poor. Active shimming (also called active shimming), the prior art discloses that a resistance type coil is used as an active shimming device and is arranged in a gradient coil, and the working principle of the active shimming device is that an external high-precision high-stability power supply is utilized to continuously supply power to the relevant coil, so that the coil generates a magnetic field to offset the uneven item of a main magnetic field. However, because the shim coils occupy a certain gradient space, and cooling channels are required to be arranged around the coils to take away joule heat of the coils, the gradient coils are thickened to some extent, so that the effective aperture of a patient is reduced, and claustrophobia of the patient is aggravated. Shim coils in a magnetic resonance imaging system occupy a high magnetic field region adapted to receive a subject. For example, a magnetic resonance imaging magnet having a cylindrical geometry is placed within the bore of the magnet, and each shim coil occupies a separate layer. Thus, the provision of shim coils reduces the usable portion of the detection aperture. In view of this, there is a need for an improved prior art magnetic resonance shimming apparatus.

SUMMERY OF THE UTILITY MODEL

In view of the above, it is necessary to provide a superconducting magnet assembly and a magnetic resonance apparatus, which address the problem that the arrangement of the shim coils at present reduces the detection space.

According to an aspect of the present application, there is provided a superconducting magnet assembly comprising:

a cryostat;

a main magnet disposed within the cryostat, the main magnet including a main coil and a main coil former for supporting the main coil;

a shim coil disposed within the cryostat, the shim coil comprising a plurality of saddle coils with at least one saddle coil disposed outside of the main magnet.

In one embodiment, the superconducting magnet assembly further comprises a shield coil and a shield bobbin for supporting the shield coil, the shield bobbin being disposed outside the main coil bobbin.

In one embodiment, one or more winding supports are disposed between the main coil bobbin and the shielding coil bobbin, the winding supports having winding slots defined therein, and the at least one saddle coil is disposed in the winding slots.

In one embodiment, the winding wire support is a bobbin sleeved outside the main coil, a plurality of saddle coils are arranged on the bobbin, and two of the saddle coils are distributed symmetrically with respect to the axial direction of the main magnet.

In one embodiment, the bobbin comprises a first bobbin and a second bobbin, and the second bobbin is fixed on the periphery of the first bobbin through an end fixing assembly.

In one embodiment, one or more of the plurality of saddle coils is comprised of a bundle of a plurality of superconducting wires wound.

In one embodiment, the outside of the bobbin is provided with a binding part for binding the wiring harness in the winding groove, and the binding part comprises at least one of a belly binding barrel, a belly binding belt and a binding strip.

According to another aspect of the present application, a magnetic resonance apparatus is provided, comprising:

a cryostat;

a main magnet disposed inside the cryostat, the main magnet including a main coil and a main coil former for supporting the main coil;

the winding bracket is arranged in the low-temperature holder and positioned on the periphery of the main magnet, and a winding groove is formed in the winding bracket;

a saddle coil disposed in the winding slot.

In one embodiment, the winding bracket is a bobbin sleeved outside the main coil, and the bobbin is provided with a plurality of winding grooves which are diffused from the center to the outside in sequence.

In one embodiment, two adjacent winding slots communicate with each other, and a wire harness made of a plurality of superconducting wires wound is disposed in the plurality of winding slots to form the saddle coil.

After adopting above-mentioned technical scheme, this application has following technological effect at least: the superconducting magnet assembly comprises a plurality of saddle-shaped coil shimming coils, and can simultaneously perform first-order shimming, second-order shimming and higher-order shimming on a main magnetic field generated by a main magnet, so that the uniformity of the main magnetic field in an imaging region is improved; saddle coils serving as shimming are arranged outside the main magnet and within the cryostat, instead of within the detection aperture formed around the main magnet, avoiding that the arrangement of shim coils leads to a significant shortening of the detection aperture.

Drawings

Fig. 1A is a schematic structural diagram of a magnetic resonance system according to an embodiment of the present application;

FIG. 1B is a cross-sectional view of a superconducting shim coil according to an embodiment of the present application;

FIG. 2 is a perspective view of a bobbin in the superconducting shim coil shown in FIG. 1B;

fig. 3 is a superconducting wire corresponding to the bobbin of fig. 2;

FIG. 4 is a plan view of the winding slot assembly shown in FIG. 2;

FIG. 5 is an enlarged view of a portion of the superconducting shim coil shown in FIG. 1B at the winding slots;

figure 6 is a current density profile of a magnetic resonance apparatus;

FIG. 7 is a schematic view of the superconducting shim coil current direction shown in FIG. 2;

fig. 8 is a schematic view of a winding frame according to an embodiment of the present application.

Wherein:

C. a magnetic resonance apparatus; 100. a superconducting shim coil; 110. a bobbin; 111. a winding slot group; 1111. a winding slot; 1112. an outlet; 120. a superconducting wire; 130. an insulating member; 140. a binding part; 200. a superconducting magnet; 210. a cryostat; 211. a refrigerator; 212. an outer container; 213. an intermediate shielding layer; 214. an inner container; 220. a main magnet; 221. a main coil framework; 222. a main coil; 223. a shield coil former; 224. a shield coil; 300. a gradient coil; 400. and (6) fixing the assembly.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present application more comprehensible, embodiments accompanying the present application are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. This application is capable of embodiments in many different forms than those described herein and that modifications may be made by one skilled in the art without departing from the spirit and scope of the application and it is therefore not intended to be limited to the specific embodiments disclosed below.

In the description of the present application, it is to be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the present application and for simplicity in description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the present application.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In this application, unless expressly stated or limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can include, for example, fixed connections, removable connections, or integral parts; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

In this application, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through intervening media. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

In order to solve the problem that the arrangement of the shimming coils in the prior art leads to the reduction of the detection space, the present application proposes a superconducting magnet assembly, which may include: a cryostat, a main magnet and shim coils. The cryostat may surround a test space into which test objects are accessible, the cryostat has an accommodation space for both the main magnet and the shim coils, and the accommodation space is isolated from the test space by a housing which cryogenically holds it. The receiving space within the cryostat may contain a cryogenic cooling medium for cooling the main magnets, shim coils etc. arranged within the cryostat. The main magnet may include a main coil and a main coil former for supporting the main coil, and the main magnet is operable to form a main magnetic field. The shimming coil comprises a plurality of saddle coils, each saddle coil can be formed by surrounding an electric conductor according to a set track, and the shimming coil can simultaneously perform first-order shimming, second-order shimming and higher-order shimming on the main magnetic field generated by the main magnet, so that the uniformity of the main magnetic field in an imaging region is improved. The saddle coil is disposed within the receiving space, and the saddle coil can be disposed adjacent to the main magnet, such as outside or inside the main magnet. In one embodiment, the saddle coils are disposed outside the main magnet rather than within the detection aperture formed around the main magnet/cryostat, thereby avoiding the problem of the provision of shim coils that result in a significant shortening of the detection aperture.

The saddle coils included in the shim coils may be formed of an electrical conductor such as copper, aluminum, or may be formed of superconducting wire formed of a superconducting material. Illustratively, the superconducting material forming the superconducting wire may be selected from one or a combination of more of niobium, thallium, copper oxide superconductor, iron-based superconductor, magnesium boride superconductor, lanthanum, strontium, and the like. Referring to fig. 1A to 5, one embodiment of the present application provides a superconducting shim coil 100 composed of superconducting wires, which is applied to a corresponding magnetic resonance apparatus C. The superconducting shimming coil 100 is applied to a magnetic resonance device and used for generating a uniform magnetic field so as to image the focus position of a patient and ensure the accuracy of an imaging result. It will be appreciated that the homogeneity of the magnetic field of the superconducting shim coils 100 may affect the performance of the magnetic resonance apparatus and thus the accuracy of the imaging performance of the magnetic resonance apparatus.

Consider that if the superconducting wire of a superconducting shim coil is laid on a planar-sized carrier and then integrally fixed to a bobbin. This form is cumbersome in the process of forming the coil. Therefore, the application provides a novel superconducting shimming coil 100, and the superconducting shimming coil 100 can ensure the uniformity of a generated magnetic field, improve the service performance of the magnetic resonance equipment, simplify the manufacturing process and facilitate the forming. The specific structure of the superconducting shim coil 100 is described in detail below.

The magnetic resonance apparatus C may include a superconducting magnet 200, gradient coils 300, radio frequency coils, and the like. Referring to fig. 1A, a superconducting magnet 200 includes: a cryostat 210 and a main magnet 220 arranged inside the cryostat. The cryostat 210 is provided with an axial through hole along the axial direction thereof to form an annular cavity in the cryostat 210, the axial through hole is used for accommodating the gradient coil 300, and the annular cavity is used for accommodating the main magnet 220, so that the cryostat 210, the gradient coil 300 and the main magnet 220 are coaxially assembled and fixed to form an integral structure.

The main magnet 220 includes a main coil 222 and a main coil former 221 supporting the main coil 222. In order to realize the superconduction of the main magnet 220, a refrigerator 211 is further disposed on the cryostat 210, the refrigerator 211 has a very low-temperature refrigeration pole (also referred to as a cold head), a cooling medium can be accommodated in the cryostat 210, and the refrigeration pole of the refrigerator 211 exchanges heat with the cooling medium in a heat transfer manner towards the cryostat 210, thereby indirectly cooling the main magnet 220. Wherein the low-temperature medium is liquid helium. Alternatively, a heat conductor may be provided between the cryostat 210 and the refrigerating pole of the refrigerator 211, and heat exchange between the two may be achieved by the heat conductor.

Cryostat 210 is a multi-layered vessel structure, and cryostat 210 includes an outer vessel 212, an inner vessel 214, and an intermediate shield 213. The outer vessel is made of steel, preferably carbon steel or stainless steel. The outer container 212 comprises a first outer cylinder and a first inner cylinder which are arranged from the center to the outside respectively along the radial direction of the outer container, the first outer cylinder and the first inner cylinder are both hollow cylindrical structures, the space surrounded by the inner side of the first inner cylinder is a detection space, sealing heads are arranged at two ends of the first outer cylinder respectively and connected to the first inner cylinder and the first outer cylinder respectively so as to seal the first outer cylinder. With this arrangement, the axial through hole is formed in the inner space of the first inner cylinder of the outer container, and an annular cavity is formed among the first inner cylinder, the first outer cylinder and the first end enclosure.

Further, an inner container 214 is arranged in the annular cavity, the inner container comprises a second inner cylinder and a second outer cylinder which are respectively arranged from the center to the inner side along the radial direction of the inner container, the second inner cylinder and the second outer cylinder are both hollow cylindrical structures, second seal heads are respectively arranged at two ends of the second inner cylinder, the second seal heads are annular structures, and the second seal heads are respectively connected to the second inner cylinder and the second outer cylinder so as to be respectively sealed.

An intermediate shielding layer 213 is arranged between the outer container and the inner container, the intermediate shielding layer comprises a third inner cylinder and a third outer cylinder which are respectively arranged from the center to the inner side along the radial direction of the intermediate shielding layer, the third inner cylinder and the third outer cylinder are both hollow cylindrical structures, third seal heads are respectively arranged at two ends of the third inner cylinder, the third seal heads are of annular structures, and the third seal heads are respectively connected to the third inner cylinder and the third outer cylinder so as to be respectively sealed.

Further, a main magnet 220 is provided in an inner space of the inner vessel 214, i.e., an accommodating space, the main magnet 220 including a main coil 222 and a main coil bobbin 221 fixing the main coil 222. It is understood that the main coil bobbin 221 has a coil slot formed therein, and the coil slot is used for receiving and fixing the main coil 222.

The superconducting magnet assembly further comprises a shielding coil and a shielding coil skeleton for supporting the shielding coil, wherein the shielding coil skeleton is arranged on the outer side of the main coil skeleton.

In this embodiment, the shield coil 224 is fixed and supported on the shield bobbin 223. The shielding coil framework 223 and the main coil framework 221 are both annular structures, and the axes of the shielding coil framework 223 and the main coil framework 221 are superposed with the axis of the inner container 214. Optionally, the radial dimension of the shield bobbin 223 is greater than the radial dimension of the main coil bobbin 221, i.e.: the shield bobbin 223 is disposed outside the main coil bobbin 221.

One or more winding supports, in which winding slots are formed, in which one or more saddle coils are disposed, may be disposed between the main coil bobbin 221 and the shield coil bobbin 223. The winding frame may be configured as a bobbin that is sleeved outside the primary coil 222, and the bobbin is provided with a plurality of saddle coils. Of course, the winding frame can also be provided with a non-cylindrical structure. In other embodiments, the bobbin may include two half cylinders at the upper and lower portions of the main coil 222, and the two half cylinders may be fitted to each other to surround the main coil 222.

In one embodiment, superconducting shim coils 100 are disposed in the space between the main coil former 221 and the shield coil former 223, the superconducting shim coils 100 being used to form the auxiliary magnetic field. The superconducting shim coils 100 may include a first superconducting shim coil disposed proximate to the primary coil and a second superconducting shim coil disposed outboard of the first superconducting shim coil. The first superconducting shim coil contains a density of the main coils that is greater than a density of the main coils contained by the second superconducting shim coil.

It is understood that the arrangement and structure of the superconducting shim coils are only given as examples in the embodiments of the present application, and the number and types of the superconducting shim coils 100 are not particularly limited, and are specifically determined according to the distribution of the main magnetic field. For example, the superconducting shim coils 100 may be arranged as a first saddle-shaped superconducting shim coil, a second saddle-shaped superconducting shim coil, a third saddle-shaped shim coil, and so on, distributed around the inner skeleton in order from the inside out. Also for example, the superconducting shim coils 100 may be provided as a solenoid shim coil, a first saddle-shaped superconducting shim coil, a second saddle-shaped superconducting shim coil, a third saddle-shaped shim coil, and so forth, distributed in that order from the inside out. Different superconducting shimming coils can be respectively arranged on the same supporting structure or different supporting structures. In one embodiment, the first and second saddle shaped superconducting shim coils may be disposed on one support structure (bobbin 110) at the same time. For example, a first saddle-shaped superconducting shim coil is disposed on the inner side of the bobbin 110, and a second saddle-shaped superconducting shim coil is disposed on the outer side of the bobbin 110, so that the magnetic resonance apparatus C can be assembled at one time during the assembly process, thereby improving the installation efficiency.

Referring to fig. 1B-4, in an embodiment, a superconducting shim coil 100 includes a bobbin 110 and a superconducting wire 120. The bobbin 110 has a saddle-shaped winding slot set 111, the winding slot set 111 includes a plurality of winding slots 1111 disposed in a layer-by-layer manner, and each winding slot 1111 is closed. The superconducting wire 120 is disposed in the winding slot 1111.

The bobbin 110 is a supporting body of the superconducting shim coil 100, and is used for supporting the superconducting wire 120, so as to ensure that the superconducting wire 120 can generate an auxiliary magnetic field on the peripheral side of the bobbin 110 during operation, and ensure the use performance. The bobbin 110 is disposed in a hollow cylindrical shape, and the hollow portion of the bobbin 110 is disposed corresponding to a magnet hole of the magnetic resonance apparatus. The superconducting wire 120 is wound on the outer side of the bobbin 110, and when the superconducting wire 120 is energized, an auxiliary magnetic field can be generated, and the auxiliary magnetic field and a main magnetic field formed by the superconducting magnet can be superposed to form uniform magnetic field distribution.

Specifically, the bobbin 110 is provided with a winding slot group 111, and the winding slot group 111 is used for realizing the layout of the superconducting wire 120. It can be understood that the outer circumferential surface of the bobbin 110 is formed with a groove, the groove is the winding groove group 111, and the superconducting wire 120 is located in the winding groove group 111, so that the superconducting wire 120 is not exposed, the service performance of the superconducting wire 120 can be ensured, the superconducting wire 120 is prevented from being separated from the bobbin 110, and the service performance is ensured.

The winding slot group 111 includes a plurality of winding slots 1111, and the plurality of winding slots 1111 are nested (diffused from the center outward in sequence). A superconducting wire 120 is disposed in each winding slot 1111. Further, a space is provided between adjacent winding grooves 1111, so that interference between adjacent superconducting wires 120 is avoided. The winding slot 1111 may be disposed in a closed manner. Thus, after the superconducting wire 120 is energized, a magnetic field can be generated on the circumferential side of the superconducting wire 120, and the uniformity of the magnetic field is ensured. Illustratively, in the present embodiment, the number of the winding slots 1111 is five, and of course, in other embodiments of the present application, the number of the winding slots 1111 may also be two, three, or even more, etc.

In other embodiments, two adjacent winding slots are communicated, and a wire harness formed by winding a plurality of superconducting wires can sequentially surround the central winding slot and enter the next winding slot through the communication space of the adjacent winding slots, so that the wire harness is continuously fixed along the track of the winding slots to form the saddle-shaped coil.

Moreover, the winding slot set 111 is arranged in a saddle shape, and the wiring track of the winding slot set 111 is calculated by using a Harmonic expression:

wherein,

is the main magnetic field and is,

and

the shimming component of the saddle-shaped shimming coil is a first order term;

shim components corresponding to the solenoid shim coils;

and

and equaling a second-order term corresponding to the shimming component of the saddle-shaped shimming coil.

The current superconducting shimming line is mainly

The homogeneity of the magnetic field is affected by the toroidal coil, which is a simple toroidal coil, and for this reason, the layout shape of the winding slot group 111 in the superconducting shim coil 100 of the present application is calculated by using the Harmonic expression,

components of the equi-saddle shim coils, cancelling

And the like. Wherein,

and

respectively, represent two first order terms in the harmonic function, which, similarly,

and

and

respectively representing four second-order terms in the harmonic function,

and

representing the six third order terms in the harmonic function, respectively. And so on, but the higher the order, the less influence on the main magnetic field and the higher the cost. Therefore, the main magnetic field corresponds to the 0 th order term in the harmonic function, and the remaining orders all affect the uniformity of the main magnetic field and need to be eliminated as much as possible. Based on this, shim coils with harmonic function terms of the first order and above are made to cancel these terms. In this embodiment, the superconducting shim coils corresponding to the lower order terms of the harmonic function are positioned proximate to the primary coil and the superconducting shim coils corresponding to the higher order terms of the harmonic function are positioned distal to the primary coil. More specifically, with continued reference to FIG. 1A, the first superconducting shim coil corresponds to the order 1 term in the harmonic function

Or

The second superconducting shim coil may correspond to a 2 nd order term in the harmonic function

And

and

the first superconducting shim coil bobbin and the second superconducting shim coil are disposed on different bobbins 110. In this way, the wiring track of the winding slot group 111 is saddle-shaped, so that the shape of each winding slot 1111 is a closed structure with asymmetric circumference, and the magnetic field uniformity of the superconducting shim coil 100 is improved.

According to the superconducting shim coil 100, the superconducting wire 120 is fixed in the winding groove 1111 of the winding barrel 110, so that the problem that the winding process of the conventional superconducting wire is complicated is effectively solved, the winding process of the superconducting wire 120 is simplified, the superconducting wire 120 is directly fixed in the winding groove 1111 to manufacture the superconducting shim coil 100, and the superconducting wire 120 is not required to be bent during winding and is directly placed in the winding groove 1111, so that the operation is convenient, and the manufacturing of the superconducting shim coil 100 is facilitated; meanwhile, the superconducting wire 120 can be ensured to generate a uniform main magnetic field during working, the service performance of the magnetic resonance equipment is ensured, and the accuracy of an imaging result is further ensured.

Optionally, the bobbin 110 is made of a non-magnetic or weakly magnetic material. Further, the bobbin 110 is made of stainless steel, aluminum alloy, copper, epoxy resin, or the like. Alternatively, the bobbin 110 may be manufactured by casting or rolling.

In one embodiment, the winding slot 1111 is formed using a five-axis machining device. It can be understood that, because the winding slot 1111 is calculated by using the Harmonic expression, the wiring track of the winding slot 1111 is an asymmetric closed structure, and the processing mode of the structure is difficult, so that the five-axis processing device is used for realizing the configuration. Specifically, the wiring trace of the winding groove 1111 is input to the five-axis machining device, and the winding groove 1111 is machined on the outer periphery of the bobbin 110 by the five-axis machining device.

With continued reference to FIG. 1, the first and second saddle-shaped superconducting shim coils are disposed on different support structures (bobbins 110), respectively, with a gap therebetween. During the assembly of the magnetic resonance apparatus C, the winding slots 1111 may be first opened on a side of the bobbin 110 facing away from the main magnet 220, and the first saddle-shaped superconducting shim coil is disposed in the winding slots 1111 to form a first combination, which is adjacent to the main magnet and has a gap with the main magnet 220; another bobbin 110 is provided outside the former bobbin 110, and a winding slot 1111 is provided in the outer circumference of the other bobbin 110, and a second saddle-shaped superconducting shim coil is provided in the winding slot 1111 to form a second combination. In this embodiment, the gap between the first combined structure and the main magnet 220 may be flowed with a cooling medium so that the main magnet 220 does not affect the cooling efficiency due to the arrangement of the superconducting shim coils; the first and second saddle shaped superconducting shim coils are spaced apart by the bobbins 110 to avoid heat build-up from each other during operation, and a gap exists between the two bobbins 110 for the inflow of cooling medium to cool the first saddle shaped superconducting shim coil. Referring to fig. 2, in one embodiment, each winding groove 1111 has an outlet port 1112, the outlet port 1112 is communicated with the outer winding groove 1111, and the outlet port 1112 of the outermost winding groove 1111 is disposed through the end of the bobbin 110. One superconducting wire 120 is wound in each winding groove 1111. The winding groove group 111 has a coil-in-coil structure, the winding groove 1111 in the inner layer communicates with the winding groove 1111 in the outer layer through an outlet port 1112, the winding groove 1111 in the outermost layer communicates with an end of the bobbin 110 in the axial direction, and the outlet port 1112 in the outermost layer serves to lead the superconducting wire 120 to the outside.

When the winding bobbin 110 winds the superconducting wire 120, one superconducting wire 120 is wound for each winding slot group 111, and one superconducting wire 120 is wound for each winding slot 1111. Illustratively, the superconducting wire 120 is wound with n turns (n ≧ 1) at the innermost side with one superconducting wire 120. The end of the superconducting wire 120 is placed at the winding groove 1111 near the wire outlet 1112, after the winding of the innermost winding groove 1111 of the superconducting wire 120 is completed, the superconducting wire 120 is wound by n turns from the wire outlet 1112 to the next winding groove 1111, and so on, after the winding of the superconducting wire 120 in each winding groove 1111 of the winding groove group 111 is completed, the superconducting wire 120 is led to the outside.

In another embodiment, the plurality of superconducting wires 120 may be first wound into a wire bundle, the wire bundle is wound from the innermost to the outer side by n turns (n ≧ 1) along the winding groove 1111, and the end of the wire bundle is placed at the winding groove 1111 near the outlet 1112. Further, the wire harness may be connected in series with another wire harness wound around the saddle coil.

Further, referring to fig. 2, four shim coils are disposed on the same circumferential layer of the bobbin 110, and the four superconducting shim coils are independently powered. Alternatively, two superconducting shim coils centered with respect to the axial direction of the bobbin 110 are connected in series with current lead connections to enable simultaneous powering of the two superconducting shim coils.

Optionally, the current of superconducting wires 120 in each winding slot group 111 is the same, and the current of superconducting wires 120 in at least two winding slots 111 is the same. Illustratively, the current in each slot group 111 is the same, and the current direction in two adjacent slot groups 111 is opposite, as shown in fig. 7, and the arrows indicate the direction of the current in the shim coils. Four saddle-shaped superconducting shimming coils are symmetrically distributed on the same layer of the bobbin 110, wherein the saddle-shaped superconducting shimming coils which are oppositely arrayed relative to the axis of the bobbin 110 have opposite flowing current directions and the same current magnitude; the corresponding currents flowing through the saddle-shaped superconducting shim coils in opposite directions relative to the center of the bobbin 110 are also of the same magnitude.

When each winding slot group 111 is wound by one superconducting wire 120, the control of the superconducting shimming coil 100 can be facilitated, the control steps are simplified, and the use is convenient.

Optionally, the groove depth of the outlet 1112 is equal to the groove depth of the winding groove 1111. Thus, the radial sizes of the superconducting wire 120 in the wire outlet 1112 and the wire winding groove 1111 are consistent, the wound superconducting wire 120 is prevented from being exposed, and the use performance is ensured.

In one embodiment, winding slots 1111 are provided independently, with each winding slot 1111 accommodating one superconducting wire 120. That is, the winding slots 1111 are not connected to each other and are independently disposed, and each winding slot 1111 is an independent channel and is wound by using the root superconducting wire 120. When winding, a superconducting wire 120 is wound in one of the winding slots 1111 for n turns. Then another superconducting wire 120 is wound in another winding slot 1111 for n turns, and so on until all winding slots 1111 are completely wound.

With continued reference to fig. 5, a plurality of superconducting wires 120 are accommodated in one winding slot 1111, the superconducting wires 120 are formed into a superconducting wire bundle, and adjacent superconducting wires 120 are insulated from each other. By the arrangement, the number of the winding slots 1111 formed in the winding drum 110 can be reduced, and the shimming efficiency is improved.

When one superconducting wire 120 is disposed in each winding slot 1111, the ends of each superconducting wire 120 are led to the outside, respectively, to enable control of the superconducting shim coil 100. Moreover, in the actual control process, the superconducting wire 120 in each winding slot 1111 may input a corresponding current according to the actual demand to adjust the strength of the magnetic field.

Of course, in other embodiments of the present application, the winding grooves 1111 may be independent from each other, and the winding grooves 1111 may be connected to each other through the outlet 1112. It should be noted that this embodiment can be implemented by the two winding methods, and the principle is substantially the same, which is not described herein.

In one embodiment, the bobbin 110 has a plurality of winding slot sets 111, and the winding slot sets 111 are symmetrically disposed on the bobbin 110. Illustratively, the number of the winding slot groups 111 is four, and four winding slot groups 111 are symmetrically arranged on the periphery of the bobbin 110. Two of the winding groove groups 111 are arranged side by side along the axial direction of the bobbin 110, and the other two winding groove groups 111 are arranged symmetrically with respect to two of the winding groove groups 111 with respect to the central axis of the bobbin 110.

Referring to fig. 1 and 5, in an embodiment, the winding slots 1111 have a symmetrical structure. The symmetrical winding grooves 1111 can ensure the uniformity of winding, and ensure that the superconducting wire 120 is uniformly wound in the winding grooves 1111. It should be noted that the shape of the winding slot 1111 is not limited in principle, and may be a bilaterally symmetrical shape. Optionally, the winding slot 1111 has a square, rectangular, circular arc, straight-line splicing, curved-line splicing, straight-line and curved-line splicing, or a dovetail slot.

Referring to fig. 1 and 5, in an embodiment, the superconducting shim coil 100 further includes an insulating member 130, the insulating member 130 being disposed on an inner wall of the winding slot 1111 for insulating the superconducting wire 120 from the bobbin 110. It is understood that the inside of the winding slot 1111 needs to be insulated to prevent the superconducting wire 120 from directly contacting the inner wall of the winding slot 1111. For this purpose, an insulating member 130 is laid inside the winding groove 1111, and the superconducting wire 120 and the bobbin 110 are separated by the insulating member 130.

Alternatively, the insulating member 130 is fixed to the inner wall of the winding slot 1111 by means of an adhesive, a screw, or the like. Optionally, the insulating member 130 is made of an insulating material. Illustratively, the insulating member 130 is an insulating varnish, an insulating paste, an insulating paper, an insulating fabric, a plastic, a rubber, or the like.

In an embodiment, the superconducting shim coil 100 further comprises tie downs 140, the tie downs 140 for tying the superconducting wire 120 in the winding slots 1111. The tie 140 may secure the superconducting wire 120 in the winding slot 1111 to prevent the superconducting wire 120 from slipping out of the winding slot 1111, so that the superconducting wire 120 may be securely positioned in the winding slot 1111 to ensure operational performance of the superconducting shim coil 100.

The binding part comprises one or more of a belly binding cylinder, a belly binding belt and a binding strip. In one embodiment, the binding portion 140 is formed in a cylindrical structure and is sleeved outside the winding barrel 110, and contacts the superconducting wire 120 in the winding slot 1111 to fix the superconducting wire 120 in the winding slot 1111. The superconducting wire 120 is confined in the winding groove 1111 by the binding portion 140, and the superconducting wire 120 is prevented from coming off the winding groove 1111.

Alternatively, the number of the binding portions 140 is plural, and the plurality of binding portions 140 are provided on the bobbin 110 at intervals so as to correspond to the superconducting wires 120 in the respective winding grooves 1111, respectively. In another embodiment of the present application, the binding portion 140 may have a hollow cylindrical structure, and the binding portion 140 is entirely fitted around the bobbin 110. Illustratively, the tie down 140 is an epoxy sleeve.

Of course, the binding portion 140 may be a fixing tape, a binding band, or the like capable of fixing the superconducting wire 120 to the winding groove 1111.

According to the superconducting shim coil 100, the superconducting wire 120 is fixed in the winding groove 1111 of the winding barrel 110, so that the problem that the winding process of the superconducting wire 120 is complicated at present is effectively solved, the winding process of the superconducting wire 120 is simplified, the superconducting wire 120 is directly fixed in the winding groove 1111 to achieve manufacturing of the superconducting shim coil 100, and the superconducting wire 120 is not required to be bent when being wound and is directly placed in the winding groove 1111, so that the operation is convenient, and the manufacturing of the superconducting shim coil 100 is facilitated; meanwhile, the superconducting wire 120 can be ensured to generate a uniform main magnetic field during working, the service performance of the magnetic resonance equipment is ensured, and the accuracy of an imaging result is further ensured.

The present application further provides a method for manufacturing a superconducting shim coil 100, comprising the following steps:

calculating the wiring track of the winding slot group 111 on the bobbin 110 according to the distribution of the main magnetic field;

processing the winding slot group 111 on the bobbin 110 according to the distribution of the winding slot group 111;

a wire harness in which one superconducting wire 120 or a plurality of superconducting wires 120 are wound is installed in the winding slot.

For example, the insulation member 130 may be first laid in the winding slot group 111, and then the wire harness may be installed in the winding slot 1111.

The magnetic resonance apparatus has a certain requirement for the distribution of the main magnetic field, and the wiring track of the winding slot group 111 on the bobbin 110 is calculated according to the requirement. After the superconducting shimming coil 100 adopts the wiring track to arrange the superconducting wire 120, the generated magnetic field can be ensured to be consistent with the magnetic field of the magnetic resonance equipment, and the imaging effect is ensured. After the wiring trace is determined, the corresponding winding groove group 111 is processed on the bobbin 110 according to the wiring trace, the superconducting wire 120 is wound to form a wire harness, and the insulating member 130 is laid on the inner wall of the winding groove 1111, so that the wire harness is arranged in the winding groove 1111.

In one embodiment, the step of calculating the routing track of the slot group 111 on the bobbin 110 according to the distribution of the main magnetic field includes:

calculating the distribution of the current density of the bobbin 110 according to the distribution of the main magnetic field;

discretizing the current density to obtain a wiring harness wiring track;

and determining the distribution of the winding slot 1111 groups according to the distribution of the wire harness tracks.

When the wiring track of the winding slot group 111 is designed, the distribution situation of the current density on the surface of the bobbin 110 is calculated according to the Harmonic expression according to the main magnetic field distribution set by magnetic resonance. The distribution of the current density is shown in fig. 6. In the figure, the region in the middle similar to a ring is a region where current is concentrated, and a superconducting wire 120 needs to be laid in the region. The current density is discretized to obtain a wiring trace of the winding slot 1111 on the bobbin 110, which is a wiring trace of the superconducting wire 120.

In one embodiment, the step of machining the bobbin set 111 on the bobbin 110 includes:

and controlling five-axis machining equipment to carve a winding slot group 111 on the bobbin 110 according to the wiring track.

It can be understood that, because the winding slot 1111 is calculated by using the Harmonic expression, the wiring track of the winding slot 1111 is an asymmetric closed structure, and the processing mode of the structure is difficult, so that the five-axis processing device is used for realizing the configuration. Specifically, the wiring trace of the winding groove 1111 is input to the five-axis machining device, and the winding groove 1111 is machined on the outer periphery of the bobbin 110 by the five-axis machining device.

In one embodiment, the winding slot group 111 includes a plurality of winding slots 1111, and the winding slots 1111 are sleeved layer by layer; the step of mounting the wire harness in the wire winding slot 1111 includes:

the wire harness after the sectional shaping is fitted into the winding groove 1111, and the wire harness after the sectional shaping is fixed in the winding groove 1111 using the binding portion 140.

As can be appreciated, the use performance of the superconducting shim coil 100 is ensured in the slot 1111.

In one embodiment, after the superconducting wire 120 is wound according to the track of the winding slot to form a wire, the superconducting wire needs to be shaped in segments to ensure that the superconducting wire 120 is reliably shaped and limited. Then, superconducting wire 120 is fixed in winding groove 111 and fixed by binding portion 140, and superconducting wire 120 is prevented from being detached from winding groove 1111. The binder 140 may fix the superconducting wire 120 in the manner described in the above embodiments, which is described in detail herein.

processing an outlet 1112 on the bobbin 110, winding the superconducting wire 120 in the winding groove 1111 for one turn, and entering the winding groove 1111 for the next turn through the outlet 1112;

or,

one superconducting wire 120 is installed in each winding slot 1111.

Alternatively, the plurality of winding slots 1111 of each winding slot group 111 are wound using one superconducting wire 120. Specifically, each winding groove 1111 has an outlet port 1112, the outlet port 1112 communicates with the outer winding groove 1111, and the outlet port 1112 of the outermost winding groove 1111 is provided through the end of the bobbin 110. One superconducting wire 120 is wound in each winding groove 1111. The winding groove group 111 has a coil-in-coil structure, the winding groove 1111 in the inner layer communicates with the winding groove 1111 in the outer layer through an outlet port 1112, the winding groove 1111 in the outermost layer communicates with an end of the bobbin 110 in the axial direction, and the outlet port 1112 in the outermost layer serves to lead the superconducting wire 120 to the outside.

Alternatively, each winding slot 1111 of the winding slot group 111 is wound with one superconducting wire 120. Specifically, each winding slot 1111 is provided independently, and each winding slot 1111 accommodates one superconducting wire 120. That is, the winding slots 1111 are not connected to each other and are independently disposed, and each winding slot 1111 is an independent channel and is wound by using the root superconducting wire 120. When winding, a superconducting wire 120 is wound in one of the winding slots 1111 for n turns. Then another superconducting wire 120 is wound in another winding slot 1111 for n turns, and so on until all winding slots 1111 are completely wound.

The present application further provides a magnetic resonance apparatus comprising a cryostat; a main magnet disposed inside the cryostat, the main magnet including a main coil and a main coil former for supporting the main coil; the winding bracket is arranged in the low-temperature holder and positioned at the periphery of the main magnet, and a winding groove is formed in the winding bracket; and a saddle-shaped coil disposed in the winding slot.

In one embodiment, the saddle coils are supported using superconducting wires, and the corresponding magnetic resonance device includes a cryostat and superconducting shim coils 100, the superconducting shim coils 100 being mounted in the cryostat. The superconducting shim coil 100 includes a bobbin 110 and a superconducting wire 120. The bobbin 110 has a saddle-shaped winding slot set 111, and the winding slot set 111 includes a plurality of winding slots 1111 that are arranged in a layer-by-layer manner (sequentially spread from the center to the outside). The superconducting wire 120 is disposed in the winding slot 1111.

The winding bracket can be a winding drum sleeved on the outer side of the main coil. Please refer to fig. 8, which is a schematic diagram of a winding frame structure in an embodiment of the present application. The winding bracket includes a first bobbin 110-1 and a second bobbin 110-2, and the second bobbin 110-2 is fixed to the outer circumference of the first bobbin 110-1 by an end fixing assembly. Specifically, the first bobbin 110-1 with the saddle-shaped coil may be first sleeved on the outer side of the main coil bobbin 221, and the fixing assembly 400 may be disposed at the end of the first bobbin and the first bobbin. The fixing member may include a fixing bar having one end extended to the main coil bobbin 221 and the other end extended to the first bobbin 110-1, and both ends of the fixing bar are respectively connected by a screw. Of course, in this embodiment, the fixing manner of the main coil bobbin 221 and the first bobbin 110-1 is not particularly limited, and for example, various connection manners such as a key, a hook, a spline, a pin, welding, gluing, and riveting may be adopted. A second bobbin 110-2 is provided at an outer side of the first bobbin 110-1. The fixing means of both are as before with the fixing assembly 400. It can be understood that the number of layers of the winding cylinders of the winding bracket can be set according to the actual shimming requirement, and three, four or more winding cylinders which are sleeved layer by layer can be set under the conditions of 5 tesla, 7 tesla or higher field intensity.

It should be noted that the structure of the superconducting shim coil 100 is mentioned above, and is not described in detail herein. The superconducting shim coils 100 of the magnetic resonance apparatus of the present application are mounted in a cryostat, and the superconducting shim coils 100 are operable to generate a magnetic field for imaging a focal site of a patient. After the superconducting shimming coil 100 of the embodiment is adopted in the magnetic resonance device, the manufacturing process can be simplified, the processing and manufacturing are convenient, the production cost is reduced, meanwhile, the uniformity of a magnetic field can be ensured, and then, the accuracy of an imaging result and the diagnosis are ensured.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the utility model. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A superconducting magnet assembly, comprising:

a cryostat;

2. The superconducting magnet assembly of claim 1, further comprising a shield coil and a shield bobbin for supporting the shield coil, the shield bobbin being disposed outside the main coil bobbin.

3. A superconducting magnet assembly according to claim 2 wherein one or more wire winding supports are provided between the main coil former and the shield coil former, wire winding slots being provided in the wire winding supports, the at least one saddle coil being provided in the wire winding slots.

4. A superconducting magnet assembly according to claim 3 wherein the wire support is a bobbin which fits over the outer side of the main coil, a plurality of saddle coils being provided on the bobbin, and two of the plurality of saddle coils being symmetrically distributed about the axis of the main magnet.

5. A superconducting magnet assembly according to claim 4 wherein the bobbins comprise a first bobbin and a second bobbin, and the second bobbin is secured to the outer periphery of the first bobbin by an end fixing assembly.

6. A superconducting magnet assembly according to any of claims 4 or 5 wherein one or more of the plurality of saddle coils is comprised of a wire bundle of a plurality of superconducting wires wound.

7. A superconducting magnet assembly according to claim 6 wherein the outside of the bobbin is provided with a tie down for tying the wire harness in the winding slot, the tie down comprising at least one of a belly tube, a belly band, a tie down bar.

8. A magnetic resonance apparatus, characterized by comprising:

a cryostat;

a saddle coil disposed in the winding slot.

9. The MRD of claim 8, wherein said winding support is a bobbin fitted around said primary coil, said bobbin having a plurality of winding slots extending from the center to the outside.

10. The magnetic resonance apparatus according to claim 9, wherein adjacent two of the winding slots communicate with each other, and a wire harness made of a plurality of superconducting wires wound is provided in the plurality of winding slots to form the saddle coil.