Magnetic Resonance Imaging System

Abstract

To provide a magnetic resonance imaging system using an open type magnetic resonance imaging device that allows a magnetic field generated outside an imaging space to be used effectively.SOLUTION: A magnetic resonance imaging system includes: one or more magnetic field units at least including an open type main magnet for generating a main magnetic field that dominantly determines a magnetic resonance frequency, a gradient magnetic field coil for generating a gradient magnetic field, and an RF coil for generating a high frequency magnetic field; and one or more image generation units for generating a magnetic resonance image of a subject using the main magnetic field, the gradient magnetic field, and the high frequency magnetic field generated by the magnetic field unit. The main magnet is disposed between examination rooms adjacent to each other. The main magnetic field generated by the open type main magnet is commonly used in the examination rooms adjacent to each other.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The embodiments disclosed herein and in the drawings relate to a magnetic resonance imaging system. [Background technology]

[0002] A magnetic resonance imaging device is an imaging device that excites the nuclear spins of a subject placed in a static magnetic field with a radio frequency (RF) signal at the Larmor frequency, and generates an image by reconstructing the magnetic resonance (MR) signals generated from the subject in response to the excitation.

[0003] Many magnetic resonance imaging (MRI) devices have a configuration called a gantry, in which a cylindrical space (called a bore) is formed. An object (e.g., a patient) lying on a tabletop is carried into the cylindrical space and imaged. A cylindrical static magnetic field magnet, a cylindrical gradient magnetic field coil, and a cylindrical RF coil (i.e., a WB (Whole Body) coil) are housed inside the gantry. In many conventional magnetic resonance imaging devices of this type, the static magnetic field magnet, the gradient magnetic field coil, and the RF coil are cylindrical, and therefore, hereinafter, this type of magnetic resonance imaging device will be referred to as a cylindrical magnetic resonance imaging device.

[0004] In a cylindrical magnetic resonance imaging apparatus, imaging is performed in a closed space inside a bore, which may make imaging difficult for some patients, such as those who suffer from claustrophobia.

[0005] In response to this, a magnetic resonance imaging apparatus has been proposed and developed in which the static magnetic field magnet, gradient magnetic field coil, and RF coil are, for example, flat in shape, and the apparatus is configured to image a subject such as a patient in an open space sandwiched between two flat static magnetic field magnets. This type of magnetic resonance imaging apparatus will be referred to as a planar open-type magnetic resonance imaging apparatus, or simply an open-type magnetic resonance imaging apparatus, hereinafter. In an open-type magnetic resonance imaging apparatus, imaging is performed in an open space, so that imaging of claustrophobic patients is also possible.

[0006] On the other hand, in an open-type magnetic resonance imaging apparatus, the magnetic field of a flat static magnetic field magnet is generated not only on the side facing the imaging space where the patient is, but also on the opposite side of the imaging space, i.e., outside the imaging space.

[0007] Conventionally, the magnetic field generated outside the imaging space has not been effectively utilized and has instead been considered harmful, necessitating the use of equipment such as a magnetic shield to suppress it. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2014-94267 A Summary of the Invention [Problem to be solved by the invention]

[0009] One of the problems to be solved by the embodiments disclosed in this specification and the drawings is to make it possible to effectively utilize the magnetic field generated outside the imaging space in a magnetic resonance imaging system using an open-type magnetic resonance imaging device. However, the problems to be solved by the embodiments disclosed in this specification and the drawings are not limited to the above problem. Problems corresponding to the effects of each configuration shown in each embodiment described later can also be positioned as other problems. [Means for solving the problem]

[0010] A magnetic resonance imaging system in one embodiment comprises one or more magnetic field units including at least an open-type main magnet that generates a main magnetic field that predominantly determines a magnetic resonance frequency, a gradient magnetic field coil that generates a gradient magnetic field, and an RF coil that generates a radio frequency magnetic field, and one or more image generating units that generate magnetic resonance images of a subject using the main magnetic field, the gradient magnetic field, and the radio frequency magnetic field generated by the magnetic field units, wherein the main magnet is disposed between adjacent examination rooms, and the main magnetic field generated by the open-type main magnet is used in common by each of the adjacent examination rooms. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a conventional open-type magnetic resonance imaging apparatus. [Diagram 2] 1 is a diagram showing an example of the configuration of a magnetic resonance imaging system according to a first embodiment. [Diagram 3] FIG. 2 is a diagram showing an example of the configuration of a first modified example of the magnetic resonance imaging system according to the first embodiment. [Figure 4] FIG. 4 is a diagram showing an example of the configuration of a second modified example of the magnetic resonance imaging system according to the first embodiment. [Diagram 5] FIG. 13 is a diagram showing an example of the configuration of a magnetic resonance imaging system according to a first example of a second embodiment. [Figure 6] FIG. 13 is a diagram showing an example of the configuration of a magnetic resonance imaging system according to a second example of the second embodiment. [Figure 7] FIG. 13 is a diagram showing an example of the configuration of a magnetic resonance imaging system according to a third example of the second embodiment. [Figure 8] FIG. 13 is a diagram showing an example of the configuration of a magnetic resonance imaging system according to a third embodiment. [Figure 9] FIG. 1 shows a configuration in which the gradient magnetic field and the radio-frequency magnetic field are controlled independently in two adjacent examination rooms. [Figure 10] FIG. 13 is a diagram showing a configuration in which the radio frequency magnetic fields in two adjacent examination rooms are controlled independently, while a common gradient magnetic field is used. [Figure 11] FIG. 13 shows a configuration in which an RF shield is provided to further suppress mutual interference of RF signals between adjacent examination rooms. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. (First embodiment) Before describing the magnetic resonance imaging system 1 according to the first embodiment, a conventional open-type magnetic resonance imaging apparatus will be briefly described.

[0013] 1 is a diagram showing an example of the configuration of a conventional open-type magnetic resonance imaging apparatus. The conventional magnetic resonance imaging apparatus has, for example, two main magnets each having a circular flat plate shape (in other words, a thin cylindrical shape).

[0014] The two main magnets are arranged to sandwich the subject. With the main magnets arranged in this way, a magnetic field is formed in the open imaging space between the two main magnets. In addition, each of the two main magnets is provided with a gradient magnetic field coil and an RF coil, which are formed, for example, in a circular plate shape like the main magnets, at a position facing the imaging space.

[0015] The subject is imaged in an open imaging space between a pair of main magnets, a pair of gradient coils, and a pair of RF coils. In Fig. 1, the dashed line extending from the main magnets in a substantially circular arc shape shows a schematic representation of the static magnetic field generated by the main magnets.

[0016] As mentioned above, in the main magnet of a conventional open-type magnetic resonance imaging apparatus, the static magnetic field generated by the main magnet is generated not only on the side facing the imaging space in which the subject (e.g., a patient) is located, but also on the opposite side of the imaging space, i.e., outside the imaging space.

[0017] Conventionally, the magnetic field generated outside the imaging space has not been effectively utilized and has been harmful. For this reason, as shown in Figure 1, a yoke was provided as a magnetic shield to suppress unnecessary static magnetic fields directed toward the outside of the imaging space.

[0018] In contrast, the magnetic resonance imaging system of each embodiment described below can effectively utilize the static magnetic field generated in both directions by the main magnet, i.e., not only the side toward the imaging space, but also the static magnetic field generated on the opposite side of the imaging space, i.e., outside the imaging space.

[0019] 2 is a diagram showing an example of the configuration of a magnetic resonance imaging system 1 according to the first embodiment. The magnetic resonance imaging system 1 is configured to include at least one or more magnetic field units 10 disposed between a plurality of adjacent examination rooms, and image generating units provided corresponding to each of the plurality of adjacent examination rooms.

[0020] Fig. 2 may be considered as a view of each examination room and the magnetic field unit 10 seen from above, or as a view of each examination room and the magnetic field unit 10 seen from the side. Below, figures similar to Fig. 3 to Fig. 8 appear, but these figures may also be considered as views of each examination room and the magnetic field unit 10 seen from above, or as views of each examination room and the magnetic field unit 10 seen from the side (except for Fig. 4).

[0021] 2, one magnetic field unit 10 is disposed in a space between adjacent first and second examination rooms. The magnetic field unit 10 may be embedded in a wall between the first and second examination rooms. Alternatively, an installation space of a predetermined size may be provided in the wall between the first and second examination rooms, and the magnetic field unit 10 may be disposed in the installation space.

[0022] A main magnet 11 is disposed in the center of the magnetic field unit 10, and a first gradient magnetic field coil 13 and a first RF coil 12 are disposed on the first examination chamber side of the main magnet 11. Meanwhile, a second gradient magnetic field coil 15 and a second RF coil 14 are disposed on the second examination chamber side of the main magnet 11. The main magnet 11, the first and second gradient magnetic field coils 13, 15, and the first and second RF coils 12, 14 each have a cylindrical shape with a predetermined thickness, for example.

[0023] The main magnet 11 generates a main magnetic field that predominantly determines the magnetic resonance frequency. Here, the "main magnetic field that predominantly determines the magnetic resonance frequency" means a magnetic field that determines the magnetic resonance frequency in a state where the magnetic field generated by the gradient coil or the magnetic field generated by the RF coil is not superimposed. The main magnetic field is a magnetic field generated only by the main magnet 11, although it does not necessarily have to have a constant magnetic field strength over time. Moreover, the main magnet 11 of this embodiment is an open-type main magnet. The open-type main magnet refers to the main magnet 11 that can form an open imaging space, and the open imaging space refers to a space in which there are no obstacles (e.g., obstacles such as a static magnetic field magnet or a gradient magnetic field coil) close to the subject in at least three of six directions surrounding the subject, i.e., up and down, left and right, and front and back. The main magnet 11 has, for example, a superconducting coil 111 therein, and generates a main magnetic field by passing a current through this superconducting coil 111. The main magnet 11 may have a configuration including a superconducting coil 111 as shown in FIG. 2, but may also have a configuration including a normal conducting coil instead of the superconducting coil 111.

[0024] When the main magnet 11 is configured to have a superconducting coil 111, a static magnetic field is generated by applying a current supplied from the main magnet power supply to the superconducting coil 111 in the excitation mode, and then, when the mode transitions to the persistent current mode, the main magnet power supply is disconnected and a magnetic field of constant strength, i.e., a static magnetic field, is generated.

[0025] On the other hand, it is also possible to apply a drive current from the main magnet power supply to the superconducting coil 111 during operation without switching to the persistent current mode, and to change the magnetic field strength by controlling the drive current. Also, even when the main magnet 11 is composed of a resistive coil, it is possible to change the magnetic field strength by controlling the drive current applied to the resistive coil. In such an operation, it is possible to change the magnetic field strength generated by the main magnet 11, and the magnetic field generated by the main magnet 11 is not strictly a "static magnetic field". Therefore, in this specification, the magnetic field generated by the main magnet 11 is referred to as the "main magnetic field" rather than the "static magnetic field".

[0026] By disposing the main magnet 11 between two adjacent examination chambers, it becomes possible for one main magnet 11 to be shared by the two adjacent examination chambers. For example, by applying a current to the superconducting coil 111 constituting the main magnet 11, a main magnetic field is generated simultaneously in both the first examination chamber and the second examination chamber. As a result, the main magnetic field generated by the main magnet 11 can be shared by each of the adjacent examination chambers.

[0027] On the other hand, the gradient magnetic field coil and the RF coil are provided separately for each of the two adjacent examination rooms. For example, in the case where the first examination room and the second examination room are adjacent to each other as shown in Fig. 2, the first gradient magnetic field used in the first examination room is generated by the first gradient magnetic field coil 13 provided on the first examination room side of the main magnet 11. On the other hand, the second gradient magnetic field used in the second examination room is generated by the second gradient magnetic field coil 15 provided on the second examination room side of the main magnet 11.

[0028] In addition, the first high-frequency magnetic field used in the first examination room is generated by a first RF coil 12 provided on the first examination room side of the main magnet 11, and the second high-frequency magnetic field used in the second examination room is generated by a second RF coil 14 provided on the second examination room side of the main magnet 11.

[0029] From the viewpoint of improving the uniformity of the main magnetic field distribution in the imaging region in each examination room (for example, the region hatched in the center of each examination room in FIG. 2), a corrective magnet 31 can be disposed in each examination room at a position facing the main magnet 11. For example, the corrective magnet 31 is disposed in the first examination room and the second examination room at a position facing the main magnet 11.

[0030] Similarly, from the viewpoint of improving the uniformity of the gradient magnetic field distribution and the high frequency magnetic field distribution, a corrective gradient magnetic field coil 33 and a corrective RF coil 32 may be arranged in the first examination room at a position facing the first gradient magnetic field coil 13 and the first RF coil 12, and similarly, a corrective gradient magnetic field coil 33 and a corrective RF coil 32 may be arranged in the second examination room at a position facing the second gradient magnetic field coil 15 and the second RF coil 14.

[0031] The corrective magnetic field unit 30 is composed of the above-mentioned corrective magnet 31, corrective gradient magnetic field coil 33, and corrective RF coil 32. The corrective magnetic field unit 30 may be embedded in the walls facing the magnetic field unit 10 of the first examination room and the second examination room, or may be provided near the walls facing the magnetic field unit 10 (for example, on the outside or inside of the walls).

[0032] On the other hand, for example, an image generating unit that generates a magnetic resonance image using a main magnetic field, a gradient magnetic field, and a high frequency magnetic field is provided for each examination room. For example, as shown in Fig. 2, a first image generating unit 51 is provided corresponding to a first examination room, and a second image generating unit 52 is provided corresponding to a second examination room.

[0033] The first image generating unit 51 is configured to include, for example, a sequence controller, a reconstruction processing circuit, an image processing circuit, a display device, etc. The sequence controller of the first image generating unit 51 controls, for example, the gradient magnetic field current and the magnitude and application timing of the transmission RF pulse applied to the first gradient magnetic field coil 13 and the first RF coil 12 based on a set pulse sequence. In addition, the reconstruction processing circuit of the first image generating unit 51 reconstructs the magnetic resonance signal received by the first RF coil 12 or a local receiving coil (not shown) installed in the first examination room to generate a magnetic resonance image. Then, the display device displays the generated magnetic resonance image.

[0034] The second image generating unit 52 has a similar configuration to the first image generating unit 51. A sequence controller of the second image generating unit 52 controls the gradient magnetic field current and the magnitude and application timing of the transmission RF pulse to be applied to the second gradient magnetic field coil 15 and the second RF coil 14 based on, for example, a set pulse sequence, and a reconstruction processing circuit of the second image generating unit 52 reconstructs a magnetic resonance signal received by the second RF coil 14 or a local receiving coil (not shown) installed in the second examination room to generate a magnetic resonance image.

[0035] The above-mentioned sequence controller and reconstruction processing circuit can be configured to include, for example, a processor that realizes each of the above-mentioned functions by executing a predetermined program, and hardware such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit) that realizes each of the above-mentioned functions.

[0036] According to the magnetic resonance imaging system 1 of the first embodiment described above, it is possible to effectively utilize the main magnetic field generated by the main magnet 11, and a main magnetic field used in two adjacent examination rooms can be generated by one main magnet 11. Furthermore, since the main magnetic field generated by the main magnet 11 is effectively utilized not only on the front side of the main magnet 11 (e.g., the first examination room side in FIG. 2) but also on the rear side of the main magnet 11 (e.g., the second examination room side in FIG. 2), there is no need to provide a magnetic field shield on either the front side or the rear side of the main magnet 11.

[0037] (Modification of the first embodiment) Fig. 3 is a diagram showing a configuration example of a first modified example of the magnetic resonance imaging system 1 according to the first embodiment. In the first embodiment shown in Fig. 2, one magnetic field unit 10 is configured to enable imaging in two examination rooms (a first examination room and a second examination room), but the number of magnetic field units 10 may be two or more, in which case the number of examination rooms that can be imaged will also be three or more.

[0038] For example, as shown in Fig. 3, a magnetic field unit 10 can be disposed between the first examination room and the second examination room, and a magnetic field unit 10 can be disposed between the second examination room and the third examination room. Furthermore, by repeating the arrangement of the magnetic field units 10 and the examination rooms shown in Fig. 3 to the left or right in Fig. 3, the number of magnetic field units 10 included in the first modified example of the magnetic resonance imaging system 1 can be increased.

[0039] Fig. 4 is a diagram showing a configuration example of a second modified example of the magnetic resonance imaging system 1 according to the first embodiment. In the first modified example shown in Fig. 3, the magnetic field units 10 and the examination chambers are arranged in a straight line, but the arrangement of the magnetic field units 10 and the examination chambers is not limited to a straight line and may be a curved line. For example, as shown in Fig. 4, the magnetic field units 10 and the examination chambers may be arranged in an arc shape.

[0040] According to the first or second modification of the first embodiment, the magnetic resonance imaging system 1 can be configured in a manner that flexibly corresponds to the number of examination rooms in a building and the arrangement of the examination rooms in the building.

[0041] Second Embodiment 5 is a diagram showing a configuration example of a magnetic resonance imaging system 1 according to a first example of the second embodiment. In the magnetic resonance imaging system 1 according to the first example of the second embodiment, the main magnet 11 includes a plurality of superconducting coils or a plurality of resistive coils, which are arranged symmetrically with respect to the central plane of the main magnet 11.

[0042] 5, the main magnet 11 includes one superconducting coil 111a and two superconducting coils 111b. The coil plane of the one superconducting coil 111a is arranged to coincide with the central plane of the main magnet 11, and the two superconducting coils 111b are arranged symmetrically with respect to the central plane of the main magnet 11.

[0043] The central plane of the main magnet 11 is a plane parallel to the bottom or top plane of the cylindrical main magnet 11 and passing through the center in the thickness direction of the main magnet 11. Also, the coil plane is a plane that includes the entire circumference of the loop-shaped conductor (including the case where there are multiple conductors) constituting the superconducting coil (or normal conducting coil), assuming that the thickness of the loop-shaped conductor is sufficiently small.

[0044] By configuring the main magnet 11 with multiple superconducting coils (or normal conducting coils) and arranging the multiple superconducting coils (or normal conducting coils) symmetrically with respect to the central plane of the main magnet 11, a magnetic field of the same magnetic field strength (A) can be generated in the imaging areas of two adjacent examination rooms, and a magnetic field distribution of a symmetric shape with respect to the central plane of the main magnet 11 can be generated in the two adjacent examination rooms.

[0045] 6 is a diagram showing a configuration example of a magnetic resonance imaging system 1 according to a second example of the second embodiment. In the magnetic resonance imaging system 1 according to the second example of the second embodiment, the main magnet 11 includes a plurality of superconducting coils or a plurality of resistive coils, which are arranged asymmetrically with respect to the central plane of the main magnet 11.

[0046] 6, the main magnet 11 includes superconducting coils 111a, 111b, and 111c that are different from one another in the coil diameter, the number of turns of the wire constituting the coils, the material, the cross-sectional size, etc. These three superconducting coils 111a, 111b, and 111c are arranged asymmetrically with respect to the central plane of the main magnet 11.

[0047] By arranging multiple superconducting coils asymmetrically with respect to the central plane of the main magnet 11, magnetic fields of different strengths, magnetic field intensity (A) and magnetic field intensity (B), can be generated for the imaging areas of two adjacent examination rooms, and a magnetic field distribution with an asymmetric shape with respect to the central plane of the main magnet 11 can be generated for the two adjacent examination rooms.

[0048] 7 is a diagram showing a configuration example of a magnetic resonance imaging system 1 according to a third example of the second embodiment. In the magnetic resonance imaging system 1 according to the third example of the second embodiment, the main magnet 11 of the magnetic field unit 10 is configured with, for example, one superconducting coil 111, while the magnetic field strengths of the corrective magnetic field units 30 and 30a are made different between adjacent examination rooms. This makes it possible to generate magnetic fields of different intensities, that is, magnetic field strength (A) and magnetic field strength (C), for the imaging regions of two adjacent examination rooms.

[0049] (Third embodiment) 8 is a diagram showing a configuration example of a magnetic resonance imaging system 1 according to the third embodiment. In the magnetic resonance imaging system 1 according to the third embodiment, only the main magnet 11 of the magnetic field unit 10 is arranged in the space between two adjacent examination rooms, and the gradient magnetic field coils 13 and 15 and the RF coils 12 and 14 are arranged in the examination rooms.

[0050] For example, only the main magnet 11 is embedded in the wall between two adjacent examination rooms, the first gradient magnetic field coil 13 and the first RF coil 12 are arranged in the first examination room, and the second gradient magnetic field coil 15 and the second RF coil 14 are arranged in the second examination room.

[0051] As for the corrective magnetic field unit 30, as shown in FIG. 8, the corrective magnet 31 may be embedded outside each examination room, for example, in the wall outside each examination room, while the corrective gradient magnetic field coil 33 and the corrective RF coil 32 may be disposed inside each examination room, or the entire corrective magnetic field unit 30 including the corrective magnet 31 may be disposed inside each examination room. With the above-mentioned arrangement, the required space between two adjacent examination rooms or the required space outside the examination rooms can be reduced.

[0052] (Other embodiments) 9 and 10 are diagrams showing current driving methods for the gradient magnetic field coil and the RF coil. Fig. 9 shows a configuration in which the gradient magnetic field and the high frequency magnetic field are controlled independently in two adjacent examination rooms. Different gradient magnetic field currents GIn(1) / GOut(1) and GIn(2) / GOut(2) are applied from two gradient magnetic field power sources to a first gradient magnetic field coil 13 that applies a first gradient magnetic field to the first examination room and a second gradient magnetic field coil 15 that applies a second gradient magnetic field to the second examination room.

[0053] Similarly, different RF pulse currents RIn(1) / ROut(1) and RIn(2) / ROut(2) are applied from two transmitting amplifiers to a first RF coil 12, which applies a first high-frequency magnetic field to the first examination room, and a second RF coil 14, which applies a second high-frequency magnetic field to the second examination room.

[0054] In contrast, Fig. 10 shows a configuration in which the high frequency magnetic fields are controlled independently in two adjacent examination rooms, but a common gradient magnetic field is used for the gradient magnetic fields. Fig. 10(a) shows a configuration in which a common gradient magnetic field current GIn / GOut is applied from one gradient magnetic field power supply to the first gradient magnetic field coil 13 for the first examination room and the second gradient magnetic field coil 15 for the second examination room. This configuration makes it possible to reduce the number of gradient magnetic field power supplies.

[0055] 10(b) illustrates a configuration in which not only the gradient magnetic field power supply but also the gradient magnetic field coil 13 is shared between the first and second examination rooms. With this configuration, it is possible to reduce the number of gradient magnetic field coils as well as the gradient magnetic field power supplies.

[0056] In addition, in both the configuration shown in Fig. 9 and the configurations shown in Fig. 10(a) and Fig. 10(b), the RF coils can be controlled independently in the first examination room and the second examination room. This allows the reception timing of the RF signal to be shifted between adjacent examination rooms, thereby suppressing mutual interference through space or ground.

[0057] 11 is a diagram illustrating a configuration in which an RF shield 16 is provided to further suppress mutual interference of RF signals between adjacent examination rooms. The RF shield 16 is provided between the gradient coils 13, 15 and the RF coils 12, 14 on each of the first examination room side and the second examination room side.

[0058] As shown in Fig. 11(a), when the RF coils 12 and 14 are disposed in the space between the first and second examination rooms, the RF shield 16 can be provided between the gradient magnetic field coils 13 and 15 and the RF coils 12 and 14 in the space between the first and second examination rooms, and can be provided so as to surround each examination room. On the other hand, as shown in Fig. 11(b), when the RF coils 12 and 14 are disposed inside each of the first and second examination rooms, the RF shield 16 can be provided between the gradient magnetic field coils 13 and 15 and the RF coils 12 and 14 in each of the first and second examination rooms, and can be provided so as to surround each examination room. The RF shield 16 shown in Figs. 11(a) and 11(b) can prevent the first high-frequency magnetic field generated by the first RF coil 12 from entering the second examination room, and can also prevent the second high-frequency magnetic field generated by the second RF coil 14 from entering the first examination room.

[0059] Up to this point, the embodiments of the magnetic resonance imaging system 1 used in a situation where a plurality of examination rooms are adjacent to each other on the same floor of a building have been described, but the arrangement of the examination rooms is not limited to this. The above-mentioned magnetic resonance imaging system 1 can also be applied in a situation where a plurality of examination rooms are adjacent to each other on upper and lower floors of a building. In this embodiment, the above-mentioned magnetic field unit 10 may be disposed in the space between the first examination room and the second examination room adjacent to each other in the vertical direction of the building, for example, embedded in the floor or ceiling between the first examination room and the second examination room adjacent to each other in the vertical direction of the building.

[0060] Further, up to this point, the shape of the main magnet 11 has been described as being a thin cylinder (i.e., flat) having a predetermined thickness, but the shape of the main magnet 11 is not limited to being flat and may be, for example, a bowl shape.

[0061] The magnetic resonance imaging system 1 described so far is configured such that, in each of two adjacent examination rooms, a corrective magnetic field unit 30 including a corrective magnet 31 is provided within (or near) the side wall at a position facing the main magnet 11 between the examination rooms, as illustrated in Fig. 2 or each of Figs. 5 to 8. As described above, this corrective magnetic field unit 30 is provided to ensure uniformity of the magnetic field distribution in each examination room.

[0062] On the other hand, imaging is also possible without necessarily assuming uniformity of the magnetic field distribution. In this case, the magnetic field distribution in the examination room may be non-uniform, for example, a magnetic field distribution that changes linearly with respect to the distance from the main magnet 11. When the magnetic field distribution is non-uniform, a region with a predetermined magnetic field strength or a controllable magnetic field strength may be set in the imaging region.

[0063] When non-uniformity in the magnetic field distribution within the examination room is acceptable, the correction magnetic field units 30 provided opposite the main magnet 11 in each examination room shown in Figure 2 or each of Figures 5 to 8 are not necessary, and it is possible to configure the system so that only one magnetic field unit 10 is provided between two adjacent examination rooms.

[0064] According to at least one of the embodiments described above, in a magnetic resonance imaging system using an open-type magnetic resonance imaging apparatus, it is possible to effectively utilize the magnetic field generated outside the imaging space.

[0065] Although some embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations of embodiments can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents as described in the claims, as well as in the scope and spirit of the invention. [Explanation of symbols]

[0066] 1. Magnetic resonance imaging system 10 Magnet unit 11 Main magnet 12 First RF coil 13 First gradient coil 14 Second RF coil 15 Second gradient coil 16 RF Shielding 30, 30a Correction magnetic field unit 31 Correction magnet 32 Correction coil 33 Correction gradient coil 51 First Image Generation Unit 52 Second Image Generation Unit 53 3rd Image Generation Unit 111 Superconducting coil

Claims

1. One or more magnetic field units including at least an open-type main magnet for generating a main magnetic field that predominantly determines a magnetic resonance frequency, a gradient magnetic field coil for generating a gradient magnetic field, and an RF coil for generating a high frequency magnetic field; one or more image generating units for generating a magnetic resonance image of a subject using the main magnetic field, the gradient magnetic field, and the high frequency magnetic field generated by the magnetic field unit; Equipped with the main magnet is disposed between adjacent examination rooms, and the main magnetic field generated by the open-type main magnet is used in common by each of the adjacent examination rooms; the main magnet is disposed between a first examination chamber and a second examination chamber adjacent to each other, and generates the main magnetic field commonly used in the first examination chamber and the second examination chamber; the gradient magnetic field coil includes a first gradient magnetic field coil that generates a first gradient magnetic field used in the first examination room, and a second gradient magnetic field coil that generates a second gradient magnetic field used in the second examination room; the RF coil includes a first RF coil for generating a first high-frequency magnetic field used in the first examination room, and a second RF coil for generating a second high-frequency magnetic field used in the second examination room; the main magnet, the first and second gradient magnetic field coils, and the first and second RF coils are disposed in a space between the first examination room and the second examination room, or are embedded in a wall between the first examination room and the second examination room; the first examination room and the second examination room are rooms surrounded by a ceiling, walls, and a floor; a high-frequency shield is provided between the first examination chamber and the second examination chamber to suppress the first high-frequency magnetic field from entering the second examination chamber and to suppress the second high-frequency magnetic field from entering the first examination chamber; Magnetic resonance imaging system.

2. at least one of a first correction magnet disposed in the first inspection chamber at a position facing the main magnet and a second correction magnet disposed in the second inspection chamber at a position facing the main magnet, At least one of the first corrective magnet and the second corrective magnet generates a corrective magnetic field that corrects the main magnetic field.

2. The magnetic resonance imaging system of claim 1.

3. One or more magnetic field units including at least an open-type main magnet for generating a main magnetic field that predominantly determines a magnetic resonance frequency, a gradient magnetic field coil for generating a gradient magnetic field, and an RF coil for generating a high frequency magnetic field; In a first inspection chamber and a second inspection chamber adjacent to each other, at least one of a first correction magnet disposed in a position facing the main magnet in the first inspection chamber and a second correction magnet disposed in a position facing the main magnet in the second inspection chamber; one or more image generating units for generating a magnetic resonance image of a subject using the main magnetic field, the gradient magnetic field, and the high frequency magnetic field generated by the magnetic field unit; Equipped with the main magnet is disposed between the first and second examination chambers adjacent to each other, and the main magnetic field generated by the open-type main magnet is used in common by each of the adjacent examination chambers; the main magnet is disposed between the first and second examination chambers adjacent to each other, and generates the main magnetic field commonly used in the first and second examination chambers; the gradient magnetic field coil includes a first gradient magnetic field coil that generates a first gradient magnetic field used in the first examination room, and a second gradient magnetic field coil that generates a second gradient magnetic field used in the second examination room; the RF coil includes a first RF coil for generating a first high-frequency magnetic field used in the first examination room, and a second RF coil for generating a second high-frequency magnetic field used in the second examination room; the main magnetic field is generated in two directions, a first direction and a second direction opposite to the first direction, by one of the main magnets, the main magnetic field generated in the first direction is used for one of the adjacent examination rooms, and the main magnetic field generated in the second direction is used for the other of the adjacent examination rooms, At least one of the first corrective magnet and the second corrective magnet generates a corrective magnetic field that corrects the main magnetic field, the first examination room and the second examination room are rooms surrounded by a ceiling, walls, and a floor; a high-frequency shield is provided between the first examination chamber and the second examination chamber to suppress the first high-frequency magnetic field from entering the second examination chamber and to suppress the second high-frequency magnetic field from entering the first examination chamber; Magnetic resonance imaging system.

4. the main magnet is disposed in a space between the first examination chamber and the second examination chamber, or embedded in a wall between the first examination chamber and the second examination chamber; the first gradient magnetic field coil and the first RF coil are disposed in the first examination room, and the second gradient magnetic field coil and the second RF coil are disposed in the second examination room.

4. A magnetic resonance imaging system according to claim 3.

5. The main magnet is configured to include a superconducting coil or a resistive coil, and the main magnetic field can be controlled by a current applied to the superconducting coil or the resistive coil.

5. A magnetic resonance imaging system according to claim 3 or 4.

6. the main magnet is configured to include a superconducting coil, and a power source that applies a current to the superconducting coil is disconnected from the superconducting coil after transition to a persistent current mode.

5. A magnetic resonance imaging system according to claim 3 or 4.

7. the main magnet includes a plurality of coils for generating the main magnetic field, and each of the plurality of coils is symmetrically disposed with respect to a central plane within the main magnet perpendicular to the direction of the main magnetic field, so that the intensity of the main magnetic field generated toward the first examination chamber and the intensity of the main magnetic field generated toward the second examination chamber are the same. A magnetic resonance imaging system according to any one of claims 3 to 6.

8. A first gradient magnetic field current applied to the first gradient magnetic field coil and a second gradient magnetic field current applied to the second gradient magnetic field coil are controlled independently of each other. A magnetic resonance imaging system according to any one of claims 3 to 7.

9. A first gradient magnetic field current applied to the first gradient magnetic field coil and a second gradient magnetic field current applied to the second gradient magnetic field coil are controlled by a common power supply. A magnetic resonance imaging system according to any one of claims 3 to 8.

10. A timing of receiving a first high frequency signal using the first RF coil and a timing of receiving a second high frequency signal using the second RF coil are controlled independently of each other. A magnetic resonance imaging system according to any one of claims 3 to 9.

11. The first examination room and the second examination room are adjacent to each other on the same floor of a building. A magnetic resonance imaging system according to any one of claims 3 to 10.

12. the main magnet is fixed between adjacent examination chambers and generates a main magnetic field while being disposed between the adjacent examination chambers; The main magnetic field generated by the open-type main magnet disposed between the adjacent examination rooms is used in common by each of the adjacent examination rooms. A magnetic resonance imaging system according to any one of claims 3 to 11.

13. One or more magnetic field units including at least an open-type main magnet for generating a main magnetic field that predominantly determines a magnetic resonance frequency, a gradient magnetic field coil for generating a gradient magnetic field, and an RF coil for generating a high frequency magnetic field; one or more image generating units for generating a magnetic resonance image of a subject using the main magnetic field, the gradient magnetic field, and the high frequency magnetic field generated by the magnetic field unit; Equipped with the main magnet is disposed between adjacent examination rooms, and the main magnetic field generated by the open-type main magnet is used in common by each of the adjacent examination rooms; the main magnet is disposed between a first examination chamber and a second examination chamber adjacent to each other, and generates the main magnetic field commonly used in the first examination chamber and the second examination chamber; the gradient magnetic field coil includes a first gradient magnetic field coil that generates a first gradient magnetic field used in the first examination room, and a second gradient magnetic field coil that generates a second gradient magnetic field used in the second examination room; the RF coil includes a first RF coil for generating a first high-frequency magnetic field used in the first examination room, and a second RF coil for generating a second high-frequency magnetic field used in the second examination room; the main magnet includes a plurality of coils for generating the main magnetic field, and the plurality of coils are arranged asymmetrically with respect to a central plane within the main magnet perpendicular to a direction of the main magnetic field, thereby making a strength of the main magnetic field generated toward the first examination chamber different from a strength of the main magnetic field generated toward the second examination chamber; the first examination room and the second examination room are rooms surrounded by a ceiling, walls, and a floor; a high-frequency shield is provided between the first examination chamber and the second examination chamber to suppress the first high-frequency magnetic field from entering the second examination chamber and to suppress the second high-frequency magnetic field from entering the first examination chamber; Magnetic resonance imaging system.

14. at least one of a first correction magnet disposed in the first inspection chamber at a position facing the main magnet and a second correction magnet disposed in the second inspection chamber at a position facing the main magnet, At least one of the first corrective magnet and the second corrective magnet generates a corrective magnetic field that corrects the main magnetic field.

14. The magnetic resonance imaging system of claim 13.

15. One or more magnetic field units including at least an open-type main magnet that generates a main magnetic field that predominantly determines a magnetic resonance frequency, a gradient magnetic field coil that generates a gradient magnetic field, and an RF coil that generates a high frequency magnetic field; one or more image generating units for generating a magnetic resonance image of a subject using the main magnetic field, the gradient magnetic field, and the high frequency magnetic field generated by the magnetic field unit; Equipped with the main magnet is disposed between adjacent examination rooms, and the main magnetic field generated by the open-type main magnet is used in common by each of the adjacent examination rooms; the main magnet is disposed between a first examination chamber and a second examination chamber adjacent to each other, and generates the main magnetic field commonly used in the first examination chamber and the second examination chamber; the gradient magnetic field coil includes a first gradient magnetic field coil that generates a first gradient magnetic field used in the first examination room, and a second gradient magnetic field coil that generates a second gradient magnetic field used in the second examination room; the RF coil includes a first RF coil for generating a first high-frequency magnetic field used in the first examination room, and a second RF coil for generating a second high-frequency magnetic field used in the second examination room; The first examination room and the second examination room are adjacent to each other on upper and lower floors of a building, the main magnet, the first and second gradient magnetic field coils, and the first and second RF coils are disposed in a space between the first examination room and the second examination room, or are embedded in a floor or a ceiling between the first examination room and the second examination room; the first examination room and the second examination room are rooms surrounded by a ceiling, walls, and a floor; a high-frequency shield is provided between the first examination chamber and the second examination chamber to suppress the first high-frequency magnetic field from entering the second examination chamber and to suppress the second high-frequency magnetic field from entering the first examination chamber; Magnetic resonance imaging system.

16. at least one of a first correction magnet disposed in a position facing the main magnet in the first inspection chamber and a second correction magnet disposed in a position facing the main magnet in the second inspection chamber, At least one of the first corrective magnet and the second corrective magnet generates a corrective magnetic field that corrects the main magnetic field.

16. The magnetic resonance imaging system of claim 15.

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