Magnetic resonance imaging device

Abstract

A magnetic resonance imaging device has: a pair of coil units for a static magnetic field for generating a uniform magnetic field in an imaging region, each of said coils being annular and having a superconducting coil; and a housing including a pair of accommodating parts in each of which an annular accommodating groove constituting a space for accommodating the coil unit in a vacuum state is formed, and a connection part for connecting the pair of accommodating parts and supporting the accommodating parts in a position facing each other across the imaging region in the vertical direction, the accommodating part and the connection part being integrally formed of a magnetic body.

Description

magnetic resonance imaging equipment

[0001] The technology of the present disclosure relates to a magnetic resonance imaging apparatus.

[0002] A magnetic resonance imaging (MRI) apparatus irradiates a subject placed in an imaging region with radio frequency pulses and uses the nuclear magnetic resonance (NMR) phenomenon that occurs when this occurs to capture images that represent the physical and chemical properties of the subject, and is particularly used for medical purposes.

[0003] MRI systems include horizontal magnetic field types that generate a uniform magnetic field in the horizontal direction and vertical magnetic field types that generate a uniform magnetic field in the vertical direction. The horizontal magnetic field type has a low-temperature section having a coil unit including a superconducting coil that generates a static magnetic field, and a vacuum vessel containing the low-temperature section that is tunnel-shaped, and the imaging region where the subject is placed is a tunnel-shaped space. In contrast, the vertical magnetic field type has a low-temperature section and a vacuum vessel containing the low-temperature section that are divided into two, and the pair of divided vacuum vessels are positioned opposite each other in the vertical direction, with the space between the pair of vacuum vessels being the imaging region where the subject is placed. Unlike the horizontal magnetic field type, which has a tunnel-shaped imaging region, the vertical magnetic field type's imaging region is open, and therefore the vertical magnetic field type is also called the open type.

[0004] As described in Japanese Patent Application Laid-Open Nos. 2008-125895, 2004-236747, and 2004-229853, the low-temperature section has a superconducting coil and is further enclosed in a vacuum vessel that houses it in a vacuum state, and this low-temperature section is attached to the vacuum vessel via a heat-insulating support.

[0005] However, when the low-temperature section and the vacuum vessel are constructed as separate bodies in this way, not only is it necessary to perform welding work at multiple locations to form the vacuum vessel that contains the low-temperature section, but the vacuum vessel also requires welding to connect complex piping containing lead wires that introduce current to the coil, etc., leaving room for improvement in the number of parts and ease of assembly.

[0006] The technology according to the present disclosure provides a magnetic resonance imaging apparatus that has fewer parts than conventional apparatuses and is easy to assemble.

[0007] The magnetic resonance imaging device according to the disclosed technology comprises a housing having a pair of coil units for a static magnetic field, each of which is an annular coil unit having a superconducting coil, and which generates a uniform magnetic field in an imaging area; a pair of storage sections, each of which has an annular storage groove that forms a space for storing the coil units in a vacuum state; and a connecting section that connects the pair of storage sections and supports them in an opposing position across the imaging area in the vertical direction, the housing having the storage sections and the connecting section integrally formed from a magnetic material.

[0008] In the housing portion, a sealing portion that seals the housing groove is preferably fixed by welding or bolts.

[0009] It is preferable that the insulating support is a rod-shaped support having a first end on the low temperature side connected to a coil unit and a second end on the room temperature side supported by a housing, and that the insulating support is arranged in such a way that its longitudinal direction extends in the vertical direction, and that the accommodating section has an insertion hole formed therein for inserting the insulating support.

[0010] The insulating support is a rod-shaped support member having a first end on the low-temperature side connected to a coil unit and a second end on the room-temperature side supported by a housing, and preferably has multiple insulating supports arranged with their longitudinal direction extending horizontally, and the storage section further has fixing sections for fixing each of the second ends.

[0011] The multiple insulating supports are arranged in rotationally symmetric positions and orientations on the circumference of the coil unit, and each second end protrudes outward from the annular outer edge of the coil unit, and each of the pair of accommodating sections accommodates two coil units with the multiple insulating supports in the same positions and orientations, in an inverted state so that the mounting surfaces of the insulating supports face each other, and it is preferable that the fixing portions formed in each of the pair of accommodating sections are formed to correspond to the positions and orientations of the multiple insulating supports attached to the two coil units accommodated in an inverted state.

[0012] It is preferable that the coil unit is provided with a radiation shield that covers the coil unit, the coil unit is accommodated in the accommodation section while covered with the radiation shield, and the heat insulating support body is in contact with the radiation shield at a midpoint in the longitudinal direction.

[0013] The housing portion preferably has a recess for housing a gradient magnetic field generating portion for generating a gradient magnetic field in the imaging region, on the inner peripheral side of the housing groove.

[0014] The inner wall of the receiving groove is preferably coated to enhance airtightness.

[0015] According to the technique of the present disclosure, it is possible to provide a magnetic resonance imaging apparatus that has fewer parts than conventional apparatuses and is easy to assemble.

[0016] 1 is a diagram showing an MRI apparatus; FIG. 2 is a diagram showing an outline of a coil unit; FIG. 3 is a diagram showing a pair of coil units; FIG. 4 is a diagram showing a housing for the coil unit; FIG. 5 is a diagram showing a housing state of the coil unit; FIG. 6 is a diagram showing an example of attachment of the coil unit to a housing; FIG. 7 is a diagram showing a coil unit of a second embodiment; FIG. 8 is a diagram showing a state in which the coil unit housed in the lower housing section is viewed vertically downward from an area in which a subject is placed; FIG. 9 is a diagram showing a state in which the coil unit housed in the upper housing section is viewed vertically downward from an area in which a subject is placed; FIG. 10 is a diagram showing an example of attachment of the coil unit of the second embodiment; FIG. 11 is a diagram showing another example of a fixing section of the heat insulating support body of the second embodiment.

[0017] First Embodiment A magnetic resonance imaging apparatus (MRI apparatus) according to a first embodiment of the disclosed technology will be described below with reference to the drawings. As shown in the overall perspective view of FIG. 1 , the MRI apparatus 10 has a pair of magnetic field generating units 11. The pair of magnetic field generating units 11 are arranged facing each other in the vertical direction and generate a static magnetic field in the vertical direction. The space between the pair of magnetic field generating units 11 forms an imaging region in which a subject 12 is placed. A bed 13 on which the subject 12 is placed is arranged in the imaging region. The MRI apparatus 10 is a vertical type that generates a static magnetic field in the vertical direction and is an open type in which the imaging region is open.

[0018] Each of the pair of magnetic field generating units 11 is provided with a static magnetic field coil unit 21 (see Figures 2 and 3, etc.) that generates a uniform static magnetic field (referred to as a uniform magnetic field) in the imaging area, and a gradient magnetic field generating unit 14 (shown by hatching) that superimposes a gradient magnetic field on the uniform magnetic field so that the magnetic field strength in the imaging area is gradient.

[0019] As is well known, the MRI apparatus 10 generates a uniform magnetic field in the imaging region, and then selectively superimposes gradient magnetic fields in three orthogonal directions in the imaging region using the gradient magnetic field generator 14. This allows NMR signals corresponding to the three orthogonal directions to be selectively acquired, and an arbitrary slice of the subject 12 to be imaged.

[0020] The housing 16 includes a pair of housing sections 17 that respectively house the static magnetic field coil unit 21 and the gradient magnetic field generator 14, and a connecting section 18 that connects the pair of housing sections 17. The connecting section 18 supports the pair of housing sections 17 in an orientation that faces each other in the vertical direction with the imaging area in between. When distinguishing between the upper and lower housing sections 17, the upper housing section is denoted by reference numeral 17U and the lower housing section is denoted by reference numeral 17L. Reference numeral 36 denotes a sealing section that hermetically seals the space in which the coil unit 21 is housed, as will be described later.

[0021] The MRI apparatus 10 further includes, as components not shown, an RF oscillator (RF: Radio Frequency) that irradiates the imaging region with electromagnetic waves of a resonant frequency that causes the subject 12 to exhibit the NMR phenomenon, a receiving coil that receives a response signal emitted when the NMR phenomenon occurs and the spin state of the hydrogen nuclei changes, a control device that controls these components, an analyzer that processes and analyzes the received signals, and a power supply circuit that supplies power to each component. In addition, the upper part of the housing 16 is provided with a refrigerator 43 that maintains the coil unit 21 and a radiation shield 26 (described later) at their respective predetermined low temperatures, and a current introduction terminal 44 for connecting the superconducting coil 22 (described later) to the power supply circuit.

[0022] Reference numeral 19 denotes a cylindrical cover member that covers a heat insulating support body 24 (see FIGS. 2 and 3, etc.) that supports a coil unit 21, which will be described later.

[0023] As shown in FIG. 2 , the coil unit 21 includes a superconducting coil 22 and a bobbin 23. The superconducting coil 22 is configured by winding a superconducting wire many times and is attached to a groove formed on the outer periphery of the bobbin 23. The bobbin 23 is configured, for example, by dividing it into two parts in the vertical direction, and the divided parts are attached and connected to the superconducting coil 22 from above and below. When the superconducting coil 22 is cooled below its critical temperature, it transitions from a normal conducting state to a superconducting state, and its electrical resistance becomes zero, allowing a circular current to circulate permanently without attenuation. This circular persistent current generates a uniform magnetic field in the imaging area.

[0024] As an example, four insulating supports 24 are attached to the coil unit 21. The insulating supports 24 are formed of, for example, carbon fiber or glass fiber. The insulating supports 24 support the coil unit 21 and maintain thermal equilibrium of the coil unit 21, which is cooled by cryogenic temperatures. The insulating supports 24 are formed of elongated rod-shaped members to increase thermal resistance, and in this example, are arranged with their longitudinal axes extending vertically. The first end 24A of each insulating support 24 is the low-temperature end connected to the coil unit 21, and the second end 24B is the room-temperature end connected to the cover 19. Since the cover 19 is fixed to the housing 16, the insulating supports 24 are supported by the housing 16 via the second end 24B and the cover 19. In this example, four insulating supports 24 are arranged at 90° intervals around the circumference of the coil unit 21. Room temperature refers to the temperature of the room in which the MRI apparatus 10 is housed, and low temperature refers to a temperature lower than room temperature. Examples of low temperatures include the temperature of the radiation shield and the temperature of the coil unit, which will be described later.

[0025] The radiation shield 26 is a member that covers the coil unit 21, and is, for example, aluminum foil. In FIG. 2 , the radiation shield 26 is conceptually shown divided into a plurality of annular members 26A and 26B. The radiation shield 26 blocks heat that is transferred from the outside to the coil unit 21 by thermal radiation. The radiation shield 26 is, for example, made of aluminum. The radiation shield 26 has a hole formed therein through which the heat insulating support 24 is inserted. The heat insulating support 24 is in contact with the radiation shield 26 at a midpoint in the longitudinal direction. Preferably, the heat insulating support 24 is in contact with the radiation shield 26 on the first end 24A side rather than the center in the longitudinal direction.

[0026] As shown in Figure 3, there is an upper coil unit 21 accommodated in the upper accommodation section 17U, and a lower coil unit 21 accommodated in the lower accommodation section 17L. The upper coil unit 21 is accommodated in the accommodation section 17U with the mounting surface of the thermal insulation support 24 facing upward. Therefore, the second end 24B on the room temperature side of the thermal insulation support 24 is positioned upward. The lower coil unit 21 is attached to the accommodation section 17L with the mounting surface of the thermal insulation support 24 facing downward. Therefore, the second end 24B on the room temperature side of the thermal insulation support 24 is positioned downward.

[0027] FIG. 4 shows the housing 16 without the coil unit 21 housed therein. FIG. 4 shows an overall view of the housing 16 and an enlarged view of the housing portion 17L on the lower side of the housing 16. The housing 16 includes a pair of housing portions 17 and a connecting portion 18 integrally formed of a magnetic material. The magnetic material is, for example, iron. The housing 16 is formed, for example, by casting. Forming the housing 16 by casting reduces the number of parts and labor compared to forming the housing 16 by forging. The housing portion 17 of the housing 16 has an annular housing groove 31 formed therein to house the annular coil unit 21. The housing groove 31 forms a space that houses the coil unit 21 under vacuum conditions. The opening of the housing groove 31 is hermetically sealed by a sealing portion 36 (see FIGS. 1 and 5 ). In the housing portion 17, the sealing portion 36 is fixed to the housing portion 17 by bolts or welding.

[0028] The inner wall of the housing groove 31 is coated to improve airtightness. One example of the coating is nickel chrome plating. When the housing 16 is constructed by casting, there is a drawback in that the airtightness is low, so the coating improves the airtightness. This makes it possible to maintain a vacuum state inside the housing groove 31.

[0029] In this way, the accommodation unit 17 also serves as a vacuum container that accommodates the coil unit 21 in a vacuum state. Furthermore, since the accommodation unit 17 and the connecting unit 18 are integrally formed from a magnetic material, the housing 16 functions as a path that returns the magnetic flux generated by each coil unit 21 to the original coil unit 21 via the connecting unit 18. In other words, since the accommodation unit 17 and the connecting unit 18 are integrally formed from a magnetic material, the housing 16 has the function of suppressing leakage magnetic fields.

[0030] The accommodation portion 17 has an insertion hole 33 formed therein for inserting the heat insulating support 24. The accommodation portion 17 also has a recess 32, located more inward than the accommodation groove 31, for accommodating the gradient magnetic field generating portion 14 that generates a gradient magnetic field in the imaging region. In addition, inside the housing 16, there are formed conduits for arranging wiring for supplying power to the coil unit 21 in the accommodation portion 17, wiring for connecting to a refrigerator (not shown) for cooling the coil unit 21, and the like.

[0031] 4 shows the accommodation groove 31 and the recess 32 of the lower accommodation portion 17L, the upper accommodation portion 17U is configured in the same manner. The upper accommodation portion 17U and the lower accommodation portion 17L are arranged such that the accommodation groove 31 and the recess 32 face each other.

[0032] Fig. 5 shows the state in which the coil unit 21 is housed in the housing portion 17. In Fig. 5, the upper housing portion 17U is shown, but the lower housing portion 17L has the same configuration except that the position is upside down.

[0033] As shown in Fig. 5, coil unit 21 is housed in housing 17 while being covered with radiation shield 26. Housing 17 shown in Fig. 5 is housed within radiation shield 26, and coil unit 21 is housed within radiation shield 26. Superconducting coil 22 is connected to a power source via current introduction terminal 44 for power supply. Furthermore, coil unit 21 and radiation shield 26 are connected to refrigerator 43 via a good conductor.

[0034] Within the accommodation groove 31, the radiation shield 26 and the coil unit 21 are maintained in a vacuum state. Because the coil unit 21 is disposed within a vacuum space, heat transfer from the outside to the coil unit 21 due to conduction and convection is suppressed. Furthermore, the radiation shield 26 also suppresses heat transfer from the outside to the coil unit 21 due to thermal radiation. By suppressing heat transfer in this manner, the coil unit 21 is maintained at an extremely low temperature required to achieve a superconducting state. For example, the coil unit 21 is maintained at a temperature of approximately 4.2 K (kelvin) to 20 K. The radiation shield 26 is maintained at a temperature between the temperature at which the coil unit 21 is maintained (extremely low temperature) and room temperature, for example, approximately 50 K to 70 K. The temperature outside the accommodation section 17 is room temperature, i.e., the temperature of the room in which the MRI apparatus 10 is accommodated, which is, for example, approximately 300 K.

[0035] Furthermore, since the heat insulating support 24 is a member whose ends are in contact with the room temperature side and the low temperature side, respectively, it is formed from a member with high thermal resistance, thereby maintaining a thermal equilibrium state of the coil unit 21. The heat insulating support 24 contacts the radiation shield 26 at a midpoint in the longitudinal direction. Preferably, the heat insulating support 24 contacts the radiation shield 26 closer to the first end 24A than the center in the longitudinal direction. This also suppresses heat transfer from the heat insulating support 24 to the radiation shield 26.

[0036] The second end 24B on the room temperature side of the heat insulating support 24 is fixed to the cover 19. The cover 19 is fixed to the accommodation portion 17. As a result, as described above, the coil unit 21 is supported by the housing 16 via the cover 19. The insertion hole 33 formed in the accommodation portion 17 and the heat insulating support 24 are not in contact with each other, and the insertion hole 33 is airtightly sealed by the cover 19.

[0037] 6 shows an example of mounting the coil unit 21 to the housing 16 configured as described above. First, in step A, the coil unit 21 is fabricated by mounting the superconducting coil 22 on the bobbin 23, and the heat insulating support 24 is connected to the coil unit 21. Two coil units 21 are fabricated, one for use on the upper side and the other for use on the lower side. The coil unit 21 fabricated in this manner is mounted to the housing 16 in which a pair of housing portions 17 and connecting portions 18 are integrally formed.

[0038] In step B, the radiation shield 26 is attached to the coil unit 21, and the coil unit 21 is accommodated in each of the accommodation grooves 31 of the pair of accommodation sections 17 while covered with the radiation shield 26. The heat insulating support body 24 is inserted into the insertion hole 33 of the accommodation section 17, and the second end 24B on the room temperature side is exposed to the outside of the accommodation section 17.

[0039] In step C, a sealing portion 36 is attached to the opening of the accommodation groove 31. Meanwhile, a cover 19 is attached to the accommodation portion 17 to cover the heat insulating support body 24 exposed to the outside. A second end 24B of the heat insulating support body 24 is fixed to the cover 19.

[0040] As described above, the MRI apparatus 10 according to the technology of the present disclosure includes a housing 16 having a pair of housing sections 17, each having an annular housing groove 31 formed therein, which constitutes a space for housing the coil unit 21 in a vacuum state, and a connecting section 18 that connects the pair of housing sections 17 and supports them in an opposing position across the imaging area in the vertical direction, the housing sections and the connecting section being integrally formed from a magnetic material. Because the housing section 17 thus functions as a vacuum container for the coil unit 21, the number of parts can be reduced compared to conventional devices in which the vacuum container is separate from the housing. Furthermore, the reduced number of parts also facilitates ease of assembly.

[0041] Furthermore, in the MRI apparatus 10 according to the technology of the present disclosure, the sealing portion 36 that seals the accommodation groove 31 is fixed in the accommodation portion 17 by welding or bolts. This simplifies sealing of the accommodation groove 31. Note that although the housing 16 is formed by casting in the above example, it may also be formed by forging. If formed by forging, the sealing portion 36 is preferably fixed by welding.

[0042] The MRI apparatus 10 according to the technique of the present disclosure includes a plurality of rod-shaped heat insulating supports 24 arranged in a position such that their longitudinal directions extend in the vertical direction. A first end 24A on the low-temperature side is connected to the coil unit 21 and a second end 24B on the room-temperature side is supported by the housing 16. The housing 17 is formed with insertion holes 33 through which the heat insulating supports 24 are inserted. Therefore, compared to a case in which the housing 17 does not have the insertion holes 33, it is easier to attach the heat insulating supports 24 supporting the coil unit 21 to the housing 16.

[0043] Furthermore, the MRI apparatus 10 according to the technology of the present disclosure includes a radiation shield 26 that covers the coil unit 21. The coil unit 21 is accommodated in the accommodation section 17 while covered with the radiation shield 26, and the heat insulating support 24 is in contact with the radiation shield 26 at a midpoint in the longitudinal direction. This makes it possible to suppress heat transfer from the heat insulating support 24 to the coil unit 21.

[0044] Furthermore, in the MRI apparatus 10 according to the technique of the present disclosure, the accommodation section 17 has a recess 32 for accommodating the gradient magnetic field generator 14 that generates a gradient magnetic field in the imaging region, located on the inner peripheral side of the accommodation groove 31. The accommodation section 17 not only functions as a vacuum container for the coil unit 21 but also as an accommodation section for the gradient magnetic field generator 14, which is advantageous in terms of reducing the number of parts.

[0045] In the MRI apparatus 10 according to the technique of the present disclosure, the inner wall of the accommodation groove 31 is coated with a coating that enhances airtightness, thereby making it possible to more reliably maintain a vacuum state within the accommodation portion 17.

[0046] [Second embodiment] In the first embodiment, the heat insulating support 24 is disposed in the coil unit 21 with its longitudinal direction extending in the vertical direction, but as in the second embodiment shown in Fig. 7, the heat insulating support 24 may be disposed with its longitudinal direction extending in the lateral direction (for example, the horizontal direction). The coil unit 21 shown in Fig. 7 is shown in a state where it is covered with a radiation shield 26.

[0047] 8 and 9, the four heat insulating supports 24 are arranged in rotationally symmetric positions and orientations on the circumference of the coil unit 21. Specifically, the first ends 24A and second ends 24B of the four heat insulating supports 24 are each equally spaced in the circumferential direction, and the four heat insulating supports 24 are arranged in positions that are four-fold symmetric as a whole.

[0048] Furthermore, second ends 24B on the room temperature side of each heat insulating support 24 protrude outward from the outer edge of the annular ring shape of the coil unit 21. As described in the first embodiment, first ends 24A on the low temperature side of the heat insulating support 24 are fixed in contact with the coil unit 21 inside the radiation shield 26. The portion of the radiation shield 26 through which the heat insulating support 24 is inserted is airtightly sealed with a cover 42.

[0049] On the other hand, the second end 24B is fixed to the accommodation portion 17. As described in the first embodiment, in order to maintain the thermal equilibrium state of the coil unit 21, the heat insulating support 24 does not contact anywhere other than the first end 24A and the second end 24B.

[0050] Furthermore, a fixing groove 41, which serves as an example of a fixing portion and comes into contact with the second end 24B to fix the second end 24B, is formed in the accommodation portion 17. The fixing groove 41 extends laterally along the longitudinal direction of the heat insulating support body 24.

[0051] 8 and 9, the lower accommodation section 17L and the upper accommodation section 17U accommodate two coil units 21 with four heat insulating supports 24 in the same positions and orientations, in a state in which the coil units 21 are upside down so that the mounting surfaces of the heat insulating supports 24 face each other. Accordingly, the multiple fixing grooves 41 formed in each of the lower accommodation section 17L and the upper accommodation section 17U are formed to correspond to the positions and orientations of the multiple heat insulating supports 24 attached to the two coil units 21 accommodated upside down.

[0052] In Figures 8 and 9, symbols S1 to S4 indicate positions at 90° intervals around the housing 17 in the housing 16 (see also Figure 7), and indicate the positions where the second ends 24B of the four heat-insulating supports 24 are disposed. Figure 8 shows the mounting surface of the heat-insulating supports 24 of the coil unit 21 as viewed from above for the lower housing 17L and the coil unit 21 housed therein. Figure 9 shows the mounting surface of the heat-insulating supports 24 of the coil unit 21 as viewed from below for the upper housing 17U and the coil unit 21 housed therein. The positions and orientations of the four heat-insulating supports 24 are the same for each of the coil units 21 in Figures 8 and 9, and the only difference is whether they are viewed from above or below. Therefore, the positions and orientations of the four heat-insulating supports 24 do not change between Figures 8 and 9.

[0053] However, since the accommodation section 17L that accommodates the coil unit 21 is viewed from above in Fig. 8 and the accommodation section 17U is viewed from below in Fig. 9, the positions S1 and S3 are upside down. The fixing grooves 41 formed in each of the pair of accommodation sections 17L and 17U are formed to correspond to the positions and postures of the multiple heat insulating supports 24 attached to the two coil units 21 that are accommodated upside down in this way.

[0054] FIG. 10 shows, like a slideshow, how two coil units 21 with the same position and orientation of the insulating support 24 are installed. As shown in FIG. 10 , the position and orientation of the insulating support 24 are the same for both the coil unit 21 accommodated in the lower accommodation section 17L and the coil unit 21 accommodated in the upper accommodation section 17U. One coil unit 21 is accommodated in the accommodation groove 31 of the lower accommodation section 17L with the mounting surface of the insulating support 24 facing upward. FIG. 10 also shows how, when the other coil unit 21 is accommodated in the accommodation groove 31 of the upper accommodation section 17U, the other coil unit 21 is flipped 180 degrees from the state in which the mounting surface of the insulating support 24 faces upward to the state in which the mounting surface faces downward. The other coil unit 21 is accommodated in the upper accommodation section 17U with the mounting surface facing downward.

[0055] As described above, in the second embodiment, the heat insulating support bodies 24 are arranged in a position in which their longitudinal direction extends horizontally. This is effective when there is no space in the vertical direction to arrange the heat insulating support bodies 24 and the cover 19 (see FIG. 1, etc.). Furthermore, the fixing grooves 41 formed in each of the pair of accommodating sections 17 are formed to correspond to the positions and orientations of the multiple heat insulating support bodies 24 attached to the two coil units 21 that are accommodated upside down. Therefore, as shown in FIG. 10, the same two coil units 21 can be accommodated in either of the pair of accommodating sections 17, which improves assembly ease.

[0056] In the above example, the second end 24B of the heat insulating support body 24 is fixed to the fixing groove 41 of the accommodation portion 17 as an example of the fixing portion, but the structure of the fixing portion that fixes the second end 24B of the heat insulating support body 24 to the accommodation portion 17 is not limited to this. For example, as shown in Fig. 11, there is also a method of fixing the second end 24B via a metal fitting (not shown) to a fixing plate 45 connected to the surface of the accommodation portion 17. In that case, the fixing plate 45 is connected to the accommodation portion 17 by bolting or welding.

[0057] The above embodiments disclose the following supplementary items. [Supplementary Item 1] A magnetic resonance imaging apparatus comprising: a pair of coil units for a static magnetic field, each having a superconducting coil, for generating a uniform magnetic field in an imaging region; a pair of housings, each having a housing groove formed in an annular shape that defines a space for housing the coil units in a vacuum; and a connecting part that connects the pair of housings and supports them in an opposing position across the imaging region in the vertical direction, the housings being formed integrally with the housings and the connecting part being made of a magnetic material. [Supplementary Item 2] The magnetic resonance imaging apparatus according to Supplementary Item 1, wherein a sealing part that seals the housing grooves in the housings is fixed by welding or bolts. [Supplementary Item 3] The magnetic resonance imaging apparatus according to Supplementary Item 1 or 2, wherein a first end on the low-temperature side is connected to the coil unit and a second end on the room-temperature side is supported by the housing, the plurality of heat-insulating supports being arranged with their longitudinal directions extending vertically, and the housings having insertion holes formed therein for inserting the heat-insulating supports. [Supplementary Item 4] The magnetic resonance imaging apparatus according to any one of Supplementary Items 1 to 3, comprising a plurality of rod-shaped thermal insulating supports, each having a first end on the low-temperature side connected to the coil unit and a second end on the room-temperature side supported by a housing, the thermal insulating supports being arranged in an orientation with their longitudinal directions extending laterally, and the accommodation unit further comprising a fixing unit for fixing each of the second ends. [Supplementary Item 5] The magnetic resonance imaging apparatus according to Supplementary Item 4, wherein the plurality of thermal insulating supports are arranged in rotationally symmetric positions and orientations on the circumference of the coil unit, and each of the second ends protrudes outward from the annular outer edge of the coil unit, and each of the pair of accommodation units accommodates two of the coil units, each of which has the same positions and orientations of the thermal insulating supports, upside down so that the mounting surfaces of the thermal insulating supports face each other, and the fixing unit formed on each of the pair of accommodation units is formed to correspond to the positions and orientations of the thermal insulating supports attached to the two coil units accommodated upside down.[Supplementary Item 6] The magnetic resonance imaging apparatus according to any one of Supplementary Items 3 to 5, further comprising a radiation shield that covers the coil unit, the coil unit being housed in the housing section while covered with the radiation shield, and the heat-insulating support body being in contact with the radiation shield at a midpoint in the longitudinal direction. [Supplementary Item 7] The magnetic resonance imaging apparatus according to any one of Supplementary Items 1 to 6, wherein the housing section has a recess, located more inward than the housing groove, that houses a gradient magnetic field generating unit that generates a gradient magnetic field in the imaging region. [Supplementary Item 8] The magnetic resonance imaging apparatus according to any one of Supplementary Items 1 to 7, wherein an inner wall of the housing groove is coated to improve airtightness.

[0058] The above-described description and illustrations are a detailed explanation of the parts related to the technology of the present disclosure and are merely an example of the technology of the present disclosure. For example, the above description of the configuration, functions, actions, and effects is an explanation of an example of the configuration, functions, actions, and effects of the parts related to the technology of the present disclosure. Therefore, it goes without saying that unnecessary parts may be deleted, new elements may be added, or replacements may be made to the above-described description and illustrations within the scope of the gist of the technology of the present disclosure. Furthermore, to avoid confusion and facilitate understanding of the parts related to the technology of the present disclosure, the above-described description and illustrations omit explanations of common technical knowledge that do not require particular explanation to enable the implementation of the technology of the present disclosure.

[0059] In this specification, "A and / or B" is synonymous with "at least one of A and B." In other words, "A and / or B" means that it may be only A, only B, or a combination of A and B. Furthermore, in this specification, the same concept as "A and / or B" is also applied when three or more things are expressed by connecting them with "and / or."

[0060] The disclosure of Japanese Patent Application No. 2024-048729, filed on March 25, 2024, is incorporated herein by reference in its entirety. In addition, all documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. A magnetic resonance imaging device comprising: a pair of coil units for static magnetic fields, each of which is annular in shape and has a superconducting coil, and which generates a uniform magnetic field in an imaging area; a pair of housings, each of which has annular housing grooves that form a space for housing the coil units in a vacuum state; and a connecting part that connects the pair of housings and supports them in an opposing position across the imaging area in the vertical direction, in which the housings and the connecting part are integrally formed from a magnetic material.

2. The magnetic resonance imaging apparatus according to claim 1, wherein a sealing portion that seals the accommodation groove is fixed in the accommodation portion by welding or bolts.

3. A magnetic resonance imaging device according to claim 1, comprising a plurality of rod-shaped heat insulating supports, each of which has a first end on the low-temperature side connected to the coil unit and a second end on the room-temperature side supported by a housing, the heat insulating supports being arranged with their longitudinal directions extending vertically, and the housing section being formed with insertion holes through which the heat insulating supports are inserted.

4. A magnetic resonance imaging device according to claim 1, comprising a plurality of rod-shaped insulating supports, each of which has a first end on the low-temperature side connected to the coil unit and a second end on the room-temperature side supported by a housing, the insulating supports being arranged with their longitudinal direction extending horizontally, and the housing further comprising fixing parts for fixing each of the second ends.

5. A magnetic resonance imaging apparatus as described in claim 4, wherein the multiple thermal insulating supports are arranged in rotationally symmetric positions and orientations on the circumference of the coil unit, and the second ends of each protrude outward from the outer edge of the annular ring of the coil unit, and each of the pair of storage sections stores two coil units with the multiple thermal insulating supports in the same positions and orientations, in an inverted state with the mounting surfaces of the thermal insulating supports facing each other, and the fixing sections formed in each of the pair of storage sections are formed to correspond to the positions and orientations of the multiple thermal insulating supports attached to the two coil units stored in an inverted state.

6. A magnetic resonance imaging apparatus according to claim 3, further comprising a radiation shield that covers the coil unit, the coil unit being housed in the housing while covered with the radiation shield, and the heat-insulating support body being in contact with the radiation shield at a midpoint in the longitudinal direction.

7. The magnetic resonance imaging apparatus according to claim 1, wherein the accommodating section has a recess located on the inner circumferential side of the accommodating groove for accommodating a gradient magnetic field generating section that generates a gradient magnetic field in the imaging region.

8. The magnetic resonance imaging apparatus according to claim 1, wherein the inner wall of the accommodation groove is coated to enhance airtightness.

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