High temperature superconducting magnetic resonance magnet

Abstract

This invention discloses a high-temperature superconducting magnetic resonance magnet, comprising a main coil frame inner cylinder and a shielding cylinder sleeved around its circumferential outer surface. At least one pair of high-temperature superconducting coils is sleeved on the outer surface of the main coil frame inner cylinder. Each pair of high-temperature superconducting coils consists of two symmetrically arranged high-temperature superconducting coil units (unit 1 and unit 2) along a plane of symmetry M, with a gap maintained between adjacent units along the length of the main coil frame inner cylinder. Simultaneously, at least one pair of high-temperature shielding coils is provided on the outer side of the shielding cylinder, each pair consisting of two symmetrically arranged high-temperature superconducting shielding coil units (unit 1 and unit 2) along a plane of symmetry M. The high-temperature superconducting magnetic resonance magnet of this invention operates at a temperature of 10-20K, eliminating the need for liquid helium, thus reducing the cost of magnetic resonance. It also generates extremely stable and uniform magnetic resonance, improving the sensitivity and resolution of the magnetic resonance magnet.

Description

Technical Field

[0001] This invention relates to the field of magnetic resonance technology, and in particular to high-temperature superconducting magnetic resonance magnets. Background Technology

[0002] The magnet is a crucial component of magnetic resonance imaging (MRI), responsible for generating a spatially uniform and temporally stable magnetic field. To improve the sensitivity and resolution of MRI, clinical medical MRI machines typically use high-field superconducting magnets with capacitances of 1.5 Tesla or 3 Tesla. The superconducting coil windings of these magnets must maintain their superconductivity at extremely low temperatures to generate a sufficiently stable and uniform magnetic field. High-field MRI magnets usually generate their magnetic field through superconducting currents in cryogenic superconducting coils. Cryogenic superconducting magnets operate at around 4K and typically require liquid helium cooling to maintain their cryogenic state. Such magnets are complex in structure, difficult to manufacture, and have high maintenance costs.

[0003] High-field magnetic resonance superconducting magnets typically have a horizontally oriented cylindrical structure, such as... Figure 1 As shown. The cylindrical structure has a coaxial cylindrical space as the sample area. The magnet's shape and interior are generally gyroscopic, including a magnet shell at room temperature, a cryogenic cold shield inside the shell, a liquid helium Dewar inside the cold shield, and a superconducting magnet coil inside the Dewar.

[0004] Superconducting magnet coils are used to generate high-intensity, highly stable, and highly uniform magnetic fields, and must maintain a persistently stable superconducting and cryogenic state. Therefore, the magnet coils are immersed in liquid helium within a cryogenic Dewar container, maintained at an extremely low temperature of 4.2 K. To effectively prevent external heat from being conducted, convection, or radiated to the liquid helium Dewar and causing it to evaporate, the superconducting coils and the Dewar's cryogenic container must be placed within a vacuum chamber encased in a radiation-shielding cold shield and multiple layers of heat-shielding films. The vacuum is maintained by the Dewar's room-temperature container. However, even the best cryogenic system cannot completely eliminate external heat from entering the liquid helium container; therefore, a cryogenic cold head is needed to re-cool and liquefy the vaporized helium back into liquid helium to maintain the system's continuously stable cryogenic state.

[0005] The technical problem to be solved by this invention is: how to design a high-temperature superconducting magnetic resonance magnet that can still generate extremely stable and uniform magnetic resonance after using a high-temperature superconducting coil to replace a low-temperature superconducting coil, so as to reduce the problems of existing 1.5T, 3T and other magnetic resonance magnets having complex structures, excessively low operating temperatures, heavy reliance on liquid helium, difficult manufacturing and high maintenance costs. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, the present invention provides a high-temperature superconducting magnetic resonance magnet that can operate at a working temperature of 10-20K without the use of liquid helium, thus reducing the cost of magnetic resonance, while also being able to generate extremely stable and uniform magnetic resonance, thereby improving the sensitivity and resolution of the magnetic resonance magnet.

[0007] The technical solution adopted in this invention is: a high-temperature superconducting magnetic resonance magnet, comprising a main coil frame inner cylinder and a shielding cylinder sleeved on its circumferential outer side.

[0008] The inner cylinder of the main coil skeleton has at least one pair of high-temperature superconducting coils sleeved on its outer surface, and has a symmetry plane M in the length direction;

[0009] Moreover, each pair of high-temperature superconducting coils consists of two symmetrically arranged high-temperature superconducting coil units, one and two, along the plane of symmetry M.

[0010] A gap is maintained between adjacent high-temperature superconducting coil unit one and / or high-temperature superconducting coil unit two in the length direction of the inner cylinder of the main coil skeleton;

[0011] Simultaneously, the shielding cylinder has at least one set of high-temperature shielding coil pairs on its outer side. Each set of high-temperature shielding coil pairs consists of a high-temperature superconducting shielding coil unit one and a high-temperature superconducting shielding coil unit two arranged symmetrically along the symmetry plane M, with an operating temperature of 10-20K. High-temperature superconductors and low-temperature superconductors are both superconductors; their difference lies in the composition and properties of their materials. They are identical in generating a magnetic field after current flows through them. Therefore, they are functionally interchangeable. The advantage of this arrangement is that the symmetrically arranged high-temperature shielding coil pairs have better magnetic resonance field-averaging performance.

[0012] Preferably, the first high-temperature superconducting coil unit, the second high-temperature superconducting coil unit, the first high-temperature superconducting shielding coil unit, and the second high-temperature superconducting shielding coil unit are each composed of several disc-shaped coil pairs connected in series.

[0013] Moreover, each of the said disc-shaped coil pairs is formed by winding a thin strip of high-temperature superconducting wire clockwise or counterclockwise into a disc-shaped coil unit, and is connected at the end of the smallest inner diameter of the disc-shaped coil unit.

[0014] Preferably, each of the disc-shaped coil pairs is made of any one or a combination of rare earth element barium copper oxide high-temperature superconducting strips, bismuth-based high-temperature superconducting strips, and magnesium diboride high-temperature superconducting strips, especially yttrium barium copper oxide high-temperature superconducting strips.

[0015] Preferably, the number of disc-shaped coil pairs is the same for each of the first high-temperature superconducting coil unit and its corresponding second high-temperature superconducting coil unit;

[0016] The number of disc-shaped coil pairs is the same for each of the first high-temperature superconducting shielded coil unit and its corresponding second high-temperature superconducting shielded coil unit.

[0017] Preferably, the width of the rare earth element barium copper oxide high-temperature superconducting band, the bismuth-based high-temperature superconducting band, and the magnesium diboride high-temperature superconducting band of each of the disc-shaped coil pairs is 6-15 mm, and the thickness is 0.02-5 mm.

[0018] Preferably, the pair of high-temperature superconducting coils is positioned with the two ends of the outermost pair close to the inner cylinder of the main coil frame, and the length of the pair of outermost pairs is 2-3 times the length of the middle pair of high-temperature superconducting coils.

[0019] Preferably, the number of high-temperature superconducting coil pairs is 2-4 sets.

[0020] Preferably, the main coil skeleton inner cylinder, the high-temperature superconducting coil pair, the shielding cylinder, and the high-temperature shielding coil pair are all immersed in helium gas at a working temperature of 10-20K.

[0021] Preferably, the main coil skeleton inner cylinder, the high-temperature superconducting coil pair, the shielding cylinder, and the high-temperature shielding coil pair are all suspended in a vacuum and connected to the cold head by a copper strip that easily conducts heat, with a temperature of 10-20K.

[0022] Preferably, the first high-temperature superconducting shielded coil unit and its corresponding second high-temperature superconducting shielded coil unit are also respectively located near the end of the shielding cylinder, and their length along the direction of the shielding cylinder is not greater than the length of the first high-temperature superconducting coil unit or the second high-temperature superconducting coil unit at the very end.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] The high-temperature superconducting magnetic resonance magnet of the present invention, after using the structure layout, can operate normally at a working temperature of 10-20K, producing the same magnetic resonance magnet as the low-temperature superconducting coil at a working temperature of 4K, and obtaining the same image.

[0025] Furthermore, since the operating temperature is much lower than the critical temperature of high-temperature superconductivity, the magnet operates relatively stably and is not prone to quenching failure due to temperature fluctuations. This is a significant advantage of using high-temperature superconducting coils as high-temperature superconducting magnetic resonance magnets.

[0026] The high-temperature superconducting magnetic resonance magnet of this invention operates at 10-20K. The cooling medium can be helium, liquid helium, or conductive cooling; liquid helium is not the only option, thus eliminating the influence of liquid helium supply. Furthermore, since the critical temperature of high-temperature superconductors is above 77K, the operating temperature of 10-20K, or even 5-70K, is lower than the critical temperature of the superconducting wire, resulting in greater magnet stability. These properties allow the high-temperature superconducting magnetic resonance magnet made with high-temperature superconducting wires to operate at higher temperatures with smaller size and lighter weight. The increased operating temperature of the magnet reduces the requirements for the cryogenic system, simplifying the magnet structure and improving operational stability.

[0027] In summary, the high-temperature superconducting magnetic resonance magnet of the present invention, after adopting the above-mentioned structural arrangement, can operate at a working temperature of 10-20K and does not require the use of liquid helium, thus reducing the cost of magnetic resonance. At the same time, it can generate extremely stable and uniform magnetic resonance, thereby improving the stability and maintenance cost of the magnetic resonance magnet. Attached Figure Description

[0028] Figure 1 A structural diagram of a magnetic field coil of a high-temperature superconducting magnetic resonance magnet;

[0029] Figure 2 A three-dimensional structural diagram of one of the coils 51 of a high-temperature superconducting coil pair 5 in a high-temperature superconducting magnetic resonance magnet;

[0030] Figure 3 This is a breakdown diagram of either high-temperature superconducting coil unit 1 51 or high-temperature superconducting coil unit 2 52, showing a three-dimensional structural diagram of high-temperature superconducting coil unit 2 52.

[0031] Figure 4 This is a schematic diagram of one embodiment of the disc-shaped coil pair 7;

[0032] Wherein: 1-Main coil skeleton inner cylinder, 2-Shielding cylinder, 3-Layout space, 4-Shielding slot, 5-High temperature superconducting coil pair, 51-High temperature superconducting coil unit one, 52-High temperature superconducting coil unit two; 6-High temperature shielding coil pair, 61-High temperature superconducting shielding coil unit one, 62-High temperature superconducting shielding coil unit two; 7-Pancake coil pair, 71 and 72-Pancake coil units. Detailed Implementation

[0033] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0034] In the description of this invention, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," and "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the combination or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, in the description of the embodiments of this invention, the positional relationships of devices such as "upper," "lower," "front," "rear," "left," and "right" in all figures are based on… Figure 1 As the standard.

[0035] like Figure 1 As shown, the high-temperature superconducting magnetic resonance magnet includes a main coil frame inner cylinder 1 and a shielding cylinder 2 sleeved around its circumference.

[0036] The inner cylinder 1 of the main coil skeleton has at least one set of high-temperature superconducting coil pairs 5 on its outer surface, and has a symmetrical plane M in the length direction. The working temperature is 10-20K.

[0037] Moreover, each of the high-temperature superconducting coil pairs 5 consists of mutually symmetrical high-temperature superconducting coil unit 1 51 and high-temperature superconducting coil unit 2 52 arranged symmetrically along the symmetry plane M.

[0038] A gap is maintained between adjacent high-temperature superconducting coil unit 1 51 and / or high-temperature superconducting coil unit 2 52 in the length direction of the inner cylinder 1 of the main coil skeleton;

[0039] Meanwhile, the shielding cylinder 2 is provided with at least one set of high-temperature shielding coil pairs 6 on the outside. Each set of high-temperature shielding coil pairs 6 consists of a high-temperature superconducting shielding coil unit 1 61 and a high-temperature superconducting shielding coil unit 2 62 arranged symmetrically along the symmetry plane C. The working temperature is 10-20K. It is used to generate a reverse shielding magnetic field to counteract the adverse effects of the high-temperature superconducting coils on the outside of the inner cylinder 1 of the main coil skeleton on the surrounding environment.

[0040] from Figure 2 and Figure 3 As shown, the high-temperature superconducting coil unit 51, the high-temperature superconducting coil unit 52, the high-temperature superconducting shielding coil unit 61, and the high-temperature superconducting shielding coil unit 62 are each composed of several disc-shaped coil pairs 7 connected in series; wherein Figure 2 This is the structure diagram after cascading. Figure 3 This is a structural diagram of either the high-temperature superconducting coil pair 5 or the high-temperature shielded coil pair 6, which exploded open.

[0041] like Figure 4As shown, each of the disc-shaped coil pairs 7 is formed by winding thin strip-shaped high-temperature superconducting wire clockwise or counterclockwise into disc-shaped coil units 71 and 72, and connected at the smallest inner diameter end of the disc-shaped coil units 71 and 72. That is, one disc-shaped coil unit 71 is formed by winding thin strip-shaped high-temperature superconducting wire clockwise, and the other disc-shaped unit 72 is formed by winding thin strip-shaped high-temperature superconducting wire counterclockwise. The two disc-shaped coil units are fixedly connected at their smallest inner diameter ends. The specific fixed connection method can be welding or other convenient fixed connection methods, such as using connectors for binding, hooking, buckling, etc., to achieve the design of magnetic field uniformity of the high-temperature superconducting coil, so as to make it more uniform and better in use. The disc-shaped coil unit pair is formed by two single-turn multilayer coils wound in opposite directions. The ends of the two disc-shaped coil units are connected at the smallest radius to form a coil with the same current direction. Figure 3 The resulting magnetic field will naturally be consistent.

[0042] More specifically, a disc coil pair consists of two single-turn multilayer coils wound in opposite directions, with the ends of the two coils connected at their minimum radius to form a coil with the same current direction.

[0043] A preferred embodiment is that each of the disc-shaped coil pairs 7 of the high-temperature superconducting magnetic resonance magnet is made of any one or a combination of yttrium barium copper oxide strips, rare earth superconducting strips, and magnesium diboride superconducting strips, which can achieve the above-mentioned high-temperature superconducting effect.

[0044] The number of disc coil pairs 7 is the same in each of the high-temperature superconducting coil unit 1 51 and its corresponding high-temperature superconducting coil unit 2 52 of the high-temperature superconducting magnetic resonance magnet.

[0045] The number of disc coil pairs 7 in each of the high-temperature superconducting shielded coil unit 1 61 and its corresponding high-temperature superconducting shielded coil unit 2 62 is also the same, which can better ensure that the high-temperature superconducting magnetic resonance magnet obtains a more uniform magnetic field.

[0046] In a preferred embodiment, the width of the yttrium barium copper oxide strip, rare earth superconductor strip, and magnesium diboride superconductor strip of each of the disc-shaped coil pairs 7 is 6-15 mm, and the thickness is 0.02-0.2 mm. In specific implementations, the widths are mainly 6 mm, 8 mm, 10 mm, and 12 mm, and the thicknesses are 0.1 mm, 0.12 mm, 0.15 mm, and 0.18 mm and 0.2 mm, respectively.

[0047] A preferred embodiment is that the pair of high-temperature superconducting coils 5 has a head end and a tail end at the two ends of the pair closest to the inner cylinder 1 of the main coil skeleton, and the length of the pair of the outermost ends is 2-3 times the length of the middle pair of high-temperature superconducting coils 5, so as to ensure that the magnetic field energy can be more evenly distributed in the layout space 3 of the entire inner cylinder of the main coil skeleton.

[0048] More preferably, the number of the high-temperature superconducting coil pairs 5 is 2-4 sets, such as... Figure 1 The high-temperature superconducting coil pairs shown are 3 pairs, namely A1-A2, B1-B2, and C1-C2. For example... Figure 1 The diagram shown is a structural example of a high-temperature superconducting magnetic resonance magnet with three groups of 5 high-temperature superconducting coil pairs (A1-A2, B1-B2, C1-C2) and 6 high-temperature shielding coil pairs as one group:

[0049] coil ID Z1 Z2 R1 R2 DP Ts A1 516.24 846.24 522.78 580.78 11 58 A2 -846.24 -516.24 522.78 580.78 11 58 B1 234.56 384.56 516.01 559.01 5 43 B2 -384.56 -234.56 516.01 559.01 5 43 C1 36.96 156.96 529.81 572.81 4 43 C2 -156.96 -36.96 529.81 572.81 4 43 D1 430.41 700.41 848.29 891.29 9 43 D2 -700.41 -430.41 848.29 891.29 9 43

[0050] In Table 1: Z1 and Z2 are the axial positions of the coil group (coordinate axes with the plane of symmetry M as the reference plane), R1 and R2 are the inner and outer radii of the coil, DP is the number of disc coil pairs contained in the coil, and Ts is the number of layers in each disc coil.

[0051] See Figure 1 As shown, the main coil frame inner cylinder 1, the high-temperature superconducting coil pair 5, the shielding cylinder 2, and the high-temperature shielding coil pair 6 are all immersed in helium gas at an operating temperature of 10-20K. This eliminates the need to maintain the temperature of these spaces at an ultra-low temperature of 4K, thus reducing the overall application cost of the nuclear magnetic resonance magnet. At an operating temperature of 10-20K, the coolant outside the main coil frame inner cylinder 1, the high-temperature superconducting coil pair 5, the shielding cylinder 2, and the high-temperature shielding coil pair 6 can be helium gas, liquid helium, or a conductive heat transfer medium, further reducing maintenance costs.

[0052] A preferred embodiment is that the high-temperature superconducting shielding coil unit 61 and its corresponding high-temperature superconducting shielding coil unit 62 are also respectively arranged close to the end of the shielding cylinder 2, and the length along the shielding cylinder direction is not greater than the length of the end high-temperature superconducting coil unit 51 or the high-temperature superconducting coil unit 52.

[0053] A preferred embodiment is that a shielding slot 4 is provided at the position of the pair of high-temperature superconducting coils 5 near the outermost end of the shielding cylinder 2, for the fixed use of the high-temperature superconducting shielding coil unit 61 and its corresponding high-temperature superconducting shielding coil unit 62, thereby improving the shielding effect of the entire high-temperature shielding coil pair 6 and improving the magnetic resonance uniformity of the entire 3T high-temperature superconducting coil pair 5. The embodiments disclosed in this invention are preferred embodiments, but are not limited thereto. Those skilled in the art can easily understand the spirit of this invention based on the above embodiments and make different extensions and variations, but as long as they do not depart from the spirit of this invention, they are all within the protection scope of this invention.

Claims

1. A high-temperature superconducting magnetic resonance magnet, comprising a main coil frame inner cylinder (1) and a shielding cylinder (2) sleeved on its circumferential outer side, characterized in that: The inner cylinder (1) of the main coil skeleton is fitted with at least one set of high-temperature superconducting coil pairs (5) on its outer surface, with the length direction symmetry plane being M; Moreover, each of the high-temperature superconducting coil pairs (5) consists of a first high-temperature superconducting coil unit (51) and a second high-temperature superconducting coil unit (52) arranged symmetrically along the plane of symmetry M. A gap is maintained between adjacent high-temperature superconducting coil unit 1 (51) and / or high-temperature superconducting coil unit 2 (52) along the length of the inner cylinder (1) of the main coil skeleton; Meanwhile, the shielding cylinder (2) is provided with at least one set of high temperature shielding coil pairs (6) on the outside. Each set of high temperature shielding coil pairs (6) is symmetrically arranged along the symmetry plane C by high temperature superconducting shielding coil unit one (61) and high temperature superconducting shielding coil unit two (62). The high-temperature superconducting coil unit 1 (51), the high-temperature superconducting coil unit 2 (52), the high-temperature superconducting shielded coil unit 1 (61), and the high-temperature superconducting shielded coil unit 2 (62) are respectively composed of several disc-shaped coil pairs (7) connected in series; Moreover, each of the said disc coil pairs (7) is formed by winding thin strip-shaped high-temperature superconducting wire clockwise or counterclockwise into disc coil units (71, 72), and is connected at the end of the smallest inner diameter of the disc coil units (71, 72); The number of disc coil pairs (7) in each of the first (51) and the corresponding second (52) of the high-temperature superconducting coil is the same; The number of disc coil pairs (7) in each of the first (61) and the corresponding second (62) of the high-temperature superconducting shielded coil unit is also the same; The shielding cylinder (2) is provided with a shielding slot (4) at the position of the pair of high-temperature superconducting coils (5) near the end, for the high-temperature superconducting shielding coil unit one (61) and its corresponding high-temperature superconducting shielding coil unit two (62) to be fixed for use.

2. The high-temperature superconducting magnetic resonance magnet according to claim 1, characterized in that: Each of the disc-shaped coil pairs (7) is made of any one or a combination of rare earth element barium copper oxide high-temperature superconducting bands, bismuth-based high-temperature superconducting bands and magnesium diboride high-temperature superconducting bands.

3. The high-temperature superconducting magnetic resonance magnet according to claim 2, characterized in that: The width of the rare earth element barium copper oxide high-temperature superconducting band, the bismuth-based high-temperature superconducting band and the magnesium diboride high-temperature superconducting band of each of the disc coil pairs (7) is 6-15 mm and the thickness is 0.02-5 mm.

4. The high-temperature superconducting magnetic resonance magnet according to any one of claims 1-3, characterized in that: The pair of high-temperature superconducting coils (5) has the two ends of the outermost pair located close to the two ends of the inner cylinder (1) of the main coil frame, and the length of the pair of outermost pairs is 2-3 times the length of the middle high-temperature superconducting coil pair (5).

5. The high-temperature superconducting magnetic resonance magnet according to claim 4, characterized in that: The number of the high-temperature superconducting coil pairs (5) is 2-4 sets.

6. The high-temperature superconducting magnetic resonance magnet according to claim 4, characterized in that: The main coil skeleton inner cylinder (1), high-temperature superconducting coil pair (5), shielding cylinder (2) and high-temperature shielding coil pair (6) are all immersed in helium gas at a working temperature of 10-20K.

7. The high-temperature superconducting magnetic resonance magnet according to claim 4, characterized in that: The high-temperature superconducting shielded coil unit one (61) and its corresponding high-temperature superconducting shielded coil unit two (62) are also respectively located near the end of the shielding cylinder (2).

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