JP7080746B2 - Magnetic resonance imaging device - Google Patents

Description

Embodiments of the present invention relate to a magnetic resonance imaging apparatus.

In recent years, in magnetic resonance imaging (MRI) devices, the diameter of the bore in which the subject is placed is increasing and the output of the gradient magnetic field is increasing, and along with this, a larger current is generated by the gradient magnetic field coil. It is supposed to be washed away. For this reason, it is important to cool the gradient magnetic field coil in the MRI apparatus.

Japanese Unexamined Patent Publication No. 2005-230543 Japanese Unexamined Patent Publication No. 2014-124195 Japanese Unexamined Patent Publication No. 2008-264536 Japanese Unexamined Patent Publication No. 08-010240 Japanese Unexamined Patent Publication No. 06-054819

The problem to be solved by the present invention is to directly cool the gradient magnetic field coil with a structurally and easily manufactured structure.

The MRI apparatus according to the embodiment includes a gradient magnetic field coil and a container. The gradient magnetic field coil generates a gradient magnetic field. The container houses the gradient magnetic field coil inside. The container is provided with a distribution port through which the refrigerant flows, and the inside of the container is filled with the refrigerant through the distribution port.

FIG. 1 is a diagram showing an overall configuration example of the MRI apparatus according to the first embodiment. FIG. 2 is a cross-sectional view showing a configuration example of the gradient magnetic field coil unit according to the first embodiment. FIG. 3 is a perspective view showing a configuration example of a shim tray included in the gradient magnetic field coil unit according to the first embodiment. FIG. 4 is a diagram showing an example of a groove formed in the X coil included in the main coil according to the first embodiment. FIG. 5 is a diagram showing an example of a groove formed in the X coil included in the main coil according to the first embodiment. FIG. 6 is a diagram showing an arrangement example of the X coil, the Y coil, and the Z coil in the gradient magnetic field coil unit according to the first embodiment. FIG. 7 is a diagram showing an arrangement example of the X coil, the Y coil, and the Z coil in the gradient magnetic field coil unit according to the second embodiment. FIG. 8 is a diagram showing an arrangement example of the X coil, the Y coil, and the Z coil in the gradient magnetic field coil unit according to the third embodiment. FIG. 9 is a diagram showing an arrangement example of the X coil, the Y coil, and the Z coil in the gradient magnetic field coil unit according to the fourth embodiment. FIG. 10 is a diagram showing an example of a groove formed in the X coil included in the main coil according to the fifth embodiment. FIG. 11 is a diagram showing an example of a groove formed in the X coil included in the main coil according to the sixth embodiment. FIG. 12 is a diagram showing an arrangement example of an inlet and an outlet in the gradient magnetic field coil unit according to the seventh embodiment.

Hereinafter, embodiments of the MRI apparatus will be described in detail with reference to the drawings. It should be noted that each drawing referred to in the following description shows a conceptual configuration, and the shape and size of each component may differ from the actual one. Further, in each drawing, the components having the same role are designated by the same reference numerals.

(First Embodiment)
FIG. 1 is a diagram showing an overall configuration example of the MRI apparatus according to the first embodiment.

For example, as shown in FIG. 1, the MRI apparatus 100 according to the present embodiment includes a static magnetic field magnet 1, a gradient magnetic field coil unit 20, a gradient magnetic field power supply 3, a whole body coil 4, a local coil 5, a sleeper 6, and a transmission circuit. 7. The receiving circuit 8, the gantry 9, the interface 10, the display 11, the storage circuit 12, and the processing circuits 13 to 16 are provided.

The static magnetic field magnet 1 generates a static magnetic field in the imaging space in which the subject S is arranged. Specifically, the static magnetic field magnet 1 is formed in a hollow substantially cylindrical shape (including a magnet having an elliptical cross section orthogonal to the central axis) in an imaging space arranged on the inner peripheral side. Generates a static magnetic field. For example, the static magnetic field magnet 1 has a cooling container formed in a substantially cylindrical shape, and a magnet such as a superconducting magnet immersed in a cooling material (for example, liquid helium or the like) filled in the cooling container. The static magnetic field magnet 1 may be a magnet that generates a static magnetic field by using, for example, a permanent magnet.

The gradient magnetic field coil unit 20 generates a gradient magnetic field in the imaging space in which the subject S is arranged. Specifically, the gradient magnetic field coil unit 20 is formed in a hollow substantially cylindrical shape (including a shape having an elliptical cross section orthogonal to the central axis), and is substantially cylindrically laminated in the radial direction. Has multiple gradient magnetic field coils. Here, the plurality of gradient magnetic field coils are located in the X-axis, Y-axis, and Z-axis directions orthogonal to each other in the imaging space arranged on the inner peripheral side based on the current supplied from the gradient magnetic field power supply 3. Generates a gradient magnetic field along.

More specifically, the gradient magnetic field coil unit 20 includes an X coil that generates a gradient magnetic field coil along the X-axis direction and a Y coil that generates a gradient magnetic field coil along the Y-axis direction as the gradient magnetic field coil. It has a Z coil that generates a gradient magnetic field coil along the Z axis direction. Here, the X-axis, the Y-axis, and the Z-axis form a device coordinate system unique to the MRI device 100. For example, the X-axis is set in the horizontal direction orthogonal to the central axis of the gradient magnetic field coil unit 20, and the Y-axis is set in the vertical direction orthogonal to the central axis of the gradient magnetic field coil unit 20. Further, the Z axis is set along the central axis of the gradient magnetic field coil unit 20.

The gradient magnetic field power supply 3 individually supplies a current to each of the X coil, the Y coil, and the Z coil of the gradient magnetic field coil unit 20, so that the gradient magnetic field power supply 3 is inclined along each axis direction of the X axis, the Y axis, and the Z axis. A magnetic field is generated in the imaging space. Specifically, the gradient magnetic field power supply 3 is inclined along the lead-out direction, the phase encoding direction, and the slice direction, which are orthogonal to each other, by appropriately supplying current to each of the X coil, the Y coil, and the Z coil. Generates a magnetic field. Here, the axis along the lead-out direction, the axis along the phase encoding direction, and the axis along the slice direction constitute a logical coordinate system for defining a slice region or a volume region to be imaged.

Then, the gradient magnetic fields along the lead-out direction, the phase encoding direction, and the slice direction are superimposed on the static magnetic field generated by the static magnetic field magnet 1 to spatially position the MR signal generated from the subject S. Give information. Specifically, the gradient magnetic field in the lead-out direction changes the frequency of the MR signal according to the position in the lead-out direction, thereby imparting position information along the lead-out direction to the MR signal. Further, the gradient magnetic field in the phase encoding direction changes the phase of the MR signal along the phase encoding direction, thereby imparting position information along the phase encoding direction to the MR signal. Further, the gradient magnetic field in the slice direction imparts position information along the slice direction to the MR signal. For example, the gradient magnetic field in the slice direction is used to determine the direction, thickness, and number of slice regions when the imaging region is the slice region, and the position in the slice direction when the imaging region is the volume region. It is used to change the phase of the MR signal according to the above.

The whole body coil 4 is an RF coil that applies an RF (Radio Frequency) magnetic field to the imaging space in which the subject S is arranged and receives an MR signal generated from the subject S due to the influence of the RF magnetic field. Specifically, the whole-body coil 4 is formed in a hollow substantially cylindrical shape (including a coil having an elliptical cross section orthogonal to the central axis), and is an RF pulse signal supplied from the transmission circuit 7. Based on the above, an RF magnetic field is applied to the imaging space arranged on the inner peripheral side. Further, the whole body coil 4 receives the MR signal generated from the subject S due to the influence of the RF magnetic field, and outputs the received MR signal to the receiving circuit 8. For example, the whole body coil 4 is a bird cage type QD (quadrature) coil.

The local coil 5 is an RF coil that receives the MR signal generated from the subject S. Specifically, the local coil 5 is an RF coil prepared for each part of the subject S, and is arranged in the vicinity of the part to be imaged when the subject S is imaged. Then, the local coil 5 receives the MR signal generated from the subject S due to the influence of the RF magnetic field applied by the whole body coil 4, and outputs the received MR signal to the receiving circuit 8. The local coil 5 may further have a function of a transmission coil that applies an RF magnetic field to the subject S. In that case, the local coil 5 is connected to the transmission circuit 7 and applies an RF magnetic field to the subject S based on the RF pulse signal supplied from the transmission circuit 7. For example, the local coil 5 is a surface coil or an array coil composed of a plurality of surface coils.

The sleeper 6 includes a top plate 6a on which the subject S is placed, and when the subject S is imaged, the top plate 6a on which the subject S is placed is moved to the imaging space. For example, the sleeper 6 is installed so that the longitudinal direction of the top plate 6a is parallel to the central axis of the static magnetic field magnet 1.

The transmission circuit 7 outputs an RF pulse signal corresponding to the resonance frequency (Larmor frequency) peculiar to the target nucleus placed in the static magnetic field to the whole body coil 4. Specifically, the transmission circuit 7 has a pulse generator, an RF generator, a modulator, and an amplifier. The pulse generator produces a waveform of the RF pulse signal. The RF generator produces an RF signal with a resonant frequency. The modulator generates an RF pulse signal by modulating the amplitude of the RF signal generated by the RF generator with the waveform generated by the pulse generator. The amplifier amplifies the RF pulse signal generated by the modulator and outputs it to the whole body coil 4.

The receiving circuit 8 generates MR signal data based on the MR signal received by the whole body coil 4 or the local coil 5, and outputs the generated MR signal data to the processing circuit 14. Specifically, the receiving circuit 8 has a preamplifier, a detector, and an A / D (Analog / Digital) converter. The preamplifier amplifies the MR signal output from the whole body coil 4 or the local coil 5. The detector detects an analog signal obtained by subtracting a resonance frequency component from the MR signal amplified by the preamplifier. The A / D converter generates MR signal data by converting the analog signal detected by the detector into a digital signal, and outputs the generated MR signal data to the processing circuit 14.

The gantry 9 has a hollow bore 9a formed in a substantially cylindrical shape (including an elliptical cross section orthogonal to the central axis), and has a static magnetic field magnet 1, a gradient magnetic field coil unit 20, and a whole body. Supports the coil 4. Specifically, in the gantry 9, the gradient magnetic field coil unit 20 is arranged on the inner peripheral side of the static magnetic field magnet 1, the whole body coil 4 is arranged on the inner peripheral side of the gradient magnetic field coil unit 20, and the whole body coil 4 is arranged. With the bore 9a arranged on the inner peripheral side, the static magnetic field magnet 1, the gradient magnetic field coil unit 20, and the whole body coil 4 are supported. Here, the space in the bore 9a of the gantry 9 becomes an imaging space in which the subject S is arranged when the subject S is imaged.

Here, an example will be described in which the MRI apparatus 100 has a so-called tunnel type configuration in which the static magnetic field magnet 1, the gradient magnetic field coil unit 20, and the whole body coil 4 are each formed in a substantially cylindrical shape. The embodiment is not limited to this. For example, the MRI apparatus 100 has a so-called open type configuration in which a pair of static magnetic field magnets, a pair of gradient magnetic field coil units, and a pair of RF coils are arranged so as to face each other across an imaging space in which the subject S is arranged. You may have. In this case, the space sandwiched by the pair of static magnetic field magnets, the pair of gradient magnetic field coil units, and the pair of RF coils corresponds to the bore in the tunnel type configuration.

The interface 10 receives various instructions and input operations of various information from the operator. Specifically, the interface 10 is connected to the processing circuit 16, converts an input operation received from the operator into an electric signal, and outputs the input operation to the processing circuit 16. For example, the interface 10 includes a trackball for setting imaging conditions and a region of interest (ROI), a switch button, a mouse, a keyboard, a touch pad for performing input operations by touching an operation surface, and a display screen. It is realized by a touch screen in which a mouse and a touch pad are integrated, a non-contact input circuit using an optical sensor, a voice input circuit, and the like. In the present specification, the interface 10 is not limited to the one provided with physical operating parts such as a mouse and a keyboard. For example, an example of the interface 10 includes an electric signal processing circuit that receives an electric signal corresponding to an input operation from an external input device provided separately from the device and outputs the electric signal to a control circuit.

The display 11 displays various information and various images. Specifically, the display 11 is connected to the processing circuit 16 and converts various information and various image data sent from the processing circuit 16 into electrical signals for display and outputs the data. For example, the display 11 is realized by a liquid crystal monitor, a CRT (Cathode Ray Tube) monitor, a touch panel, or the like.

The storage circuit 12 stores various data. Specifically, the storage circuit 12 stores MR signal data and image data. For example, the storage circuit 12 is realized by a semiconductor memory element such as a RAM (Random Access Memory) or a flash memory, a hard disk, an optical disk, or the like.

The processing circuit 13 has a sleeper control function 13a. The sleeper control function 13a controls the operation of the sleeper 6 by outputting an electric signal for control to the sleeper 6. For example, the bed control function 13a receives an instruction from the operator to move the top plate 6a in the longitudinal direction, the vertical direction, or the left-right direction via the interface 10, and moves the bed 6a according to the received instruction. The moving mechanism of the top plate 6a included in 6 is operated.

The processing circuit 14 has a data acquisition function 14a. The data collection function 14a collects MR signal data of the subject S by executing various pulse sequences. Specifically, the data acquisition function 14a executes a pulse sequence by driving the gradient magnetic field power supply 3, the transmission circuit 7, and the reception circuit 8 according to the sequence execution data output from the processing circuit 16. Here, the sequence execution data is data representing a pulse sequence, the timing at which the gradient magnetic field power supply 3 supplies a current to the gradient magnetic field coil unit 20, the strength of the supplied current, and the transmission circuit 7 supplying the whole body coil 4. This is information that defines the strength and supply timing of the RF pulse signal to be performed, the detection timing at which the receiving circuit 8 detects the MR signal, and the like. Then, the data acquisition function 14a receives MR signal data from the reception circuit 8 as a result of executing the pulse sequence, and stores the received MR signal data in the storage circuit 12. Here, the set of MR signal data received by the data acquisition function 14a is arranged two-dimensionally or three-dimensionally according to the position information given by the read-out gradient magnetic field, the phase-encoded gradient magnetic field, and the slice gradient magnetic field described above. By doing so, it is stored in the storage circuit 12 as data constituting the k space.

The processing circuit 15 has an image generation function 15a. The image generation function 15a generates an image based on the MR signal data stored in the storage circuit 12. Specifically, the image generation function 15a reads out the MR signal data stored in the storage circuit 12 by the data collection function 14a, and performs post-processing, that is, reconstruction processing such as Fourier transform on the read MR signal data. Generate an image with. Further, the image generation function 15a stores the image data of the generated image in the storage circuit 12.

The processing circuit 16 has a main control function 16a. The main control function 16a controls the entire MRI apparatus 100 by controlling each component of the MRI apparatus 100. Specifically, the main control function 16a displays a GUI (Graphical User Interface) for receiving various instructions and input operations of various information from the operator on the display 11. Then, the main control function 16a controls each component of the MRI apparatus 100 according to the input operation received via the interface 10. For example, the main control function 16a receives input of imaging conditions from the operator via the interface 10. Then, the main control function 16a generates sequence execution data based on the received imaging conditions, and transmits the sequence execution data to the processing circuit 14 to execute various pulse sequences. Further, for example, the main control function 16a reads image data from the storage circuit 12 and outputs the image data to the display 11 in response to a request from the operator.

Here, the processing circuits 13 to 16 described above are realized by, for example, a processor. In this case, the processing function of each processing circuit is stored in the storage circuit 12 in the form of a program that can be executed by a computer, for example. Each processing circuit realizes a function corresponding to each program by reading each program from the storage circuit 12 and executing the program. Here, each processing circuit may be configured by a plurality of processors, and each processing function may be realized by each processor executing a program. Further, the processing functions of each processing circuit may be appropriately distributed or integrated into a single processing circuit or a plurality of processing circuits. Further, here, a single storage circuit 12 has been described as storing a program corresponding to each processing function, but a plurality of storage circuits are distributed and arranged so that the processing circuits correspond from individual storage circuits. It may be configured to read the program.

The overall configuration of the MRI apparatus 100 according to the present embodiment has been described above. Under such a configuration, the MRI apparatus 100 according to the present embodiment has a configuration for cooling the gradient magnetic field coil included in the gradient magnetic field coil unit 20.

Here, in recent years, in the MRI apparatus, the diameter of the bore in which the subject is placed has been increased and the output of the gradient magnetic field has been increased, and along with this, a larger current has been passed through the gradient magnetic field coil. There is. For this reason, it is important to cool the gradient magnetic field coil in the MRI apparatus.

Generally, as a cooling method for a gradient magnetic field coil, for example, an indirect method in which a cooling tube is arranged near the pattern of the gradient magnetic field coil to allow a refrigerant to flow through the cooling tube, or a hollow conductor is used for the pattern of the gradient magnetic field coil. A direct method of forming and circulating a magnetic field through the hollow conductor is known.

However, the indirect method has a drawback that the cooling efficiency is low when the refrigerant is flowed by the same flow rate as compared with the direct method. Further, in the direct method, the thickness of the hollow conductor is limited, so that the pressure loss of the refrigerant becomes large. Therefore, the direct method has a drawback that the flow path of the refrigerant is branched (divided), and as a result, the structure of the gradient magnetic field coil unit becomes complicated and the manufacturing becomes difficult.

Therefore, the MRI apparatus 100 according to the present embodiment is configured to be able to directly cool the gradient magnetic field coil with a structure that is structurally and easily manufactured.

Specifically, the MRI apparatus 100 according to the present embodiment includes a container for accommodating a gradient magnetic field coil inside. The container is provided with a distribution port through which the refrigerant flows, and the inside of the container is filled with the refrigerant through the distribution port.

According to such a configuration, the gradient magnetic field coil can be directly cooled by the refrigerant filled in the container without using a hollow conductor. Therefore, according to the present embodiment, the gradient magnetic field coil can be directly cooled with a structure that is structurally and easily manufactured as compared with the case where a hollow conductor is used.

Hereinafter, the configuration of the above-mentioned MRI apparatus 100 will be described in more detail. In this embodiment, an example will be described in which the gradient magnetic field coil unit 20 is configured as an ASGC (Actively Shielded Gradient Coil) having a main coil for generating a gradient magnetic field and a shield coil for canceling the leakage gradient magnetic field. do.

FIG. 2 is a cross-sectional view showing a configuration example of the gradient magnetic field coil unit 20 according to the first embodiment. Here, FIG. 2 shows a cross section along the vertical direction passing through the central axis of the gradient magnetic field coil unit 20, and shows a cross section of the upper portion of the cylindrical shape of the gradient magnetic field coil unit 20. In FIG. 2, the upper side shows the outer peripheral side of the gradient magnetic field coil unit 20, and the lower side shows the inner peripheral side of the gradient magnetic field coil unit 20.

For example, as shown in FIG. 2, the gradient magnetic field coil unit 20 according to the present embodiment has a main coil 21, a shield coil 22, a shim tray guide 23, a shim tray 24, and a container 25.

The main coil 21 is configured by laminating the X coil 21x, the Y coil 21y, and the Z coil 21z formed in a substantially cylindrical shape in the radial direction. Here, the X coil 21x, the Y coil 21y, and the Z coil 21z of the main coil 21 are located in the imaging space arranged on the inner peripheral side in the X-axis, Y-axis, and Z-axis directions orthogonal to each other. Generates a gradient magnetic field along. Specifically, the X coil 21x is a saddle coil formed in a saddle shape, and generates a gradient magnetic field along the X axis. Further, the Y coil 21y is a saddle coil like the X coil, and generates a gradient magnetic field along the Y axis. Further, the Z coil 21z is a solenoid coil formed in a spiral shape and generates a gradient magnetic field along the Z axis.

The shield coil 22 is arranged on the outer peripheral side of the main coil 21, and like the main coil 21, the X coil 22x, the Y coil 22y, and the Z coil 22z formed in a substantially circumferential shape are laminated in the radial direction. It is composed of. Here, the X coil 22x, the Y coil 22y, and the Z coil 22z of the shield coil 22 are currents in the directions opposite to the currents flowing through the X coil 21x, the Y coil 21y, and the Z coil 21z of the main coil 21, respectively. Is generated to generate a magnetic field that cancels the leaked gradient magnetic field leaking to the outside of the gradient magnetic field coil unit 20.

The shim tray guide 23 is a member formed in a cylindrical shape of an elongated rectangular parallelepiped, and has openings on both end faces in the longitudinal direction for inserting the shim tray 24. Here, a plurality of shim tray guides 23 are arranged at equal intervals along the circumferential direction of each coil in the region sandwiched between the main coil 21 and the shield coil 22, and each of them is parallel to each other. It is arranged like this. A shim tray 24 is inserted into each shim tray guide 23.

FIG. 3 is a perspective view showing a configuration example of the shim tray 24 included in the gradient magnetic field coil unit 20 according to the first embodiment.

For example, as shown in FIG. 3, the shim tray 24 is composed of an elongated box-shaped tray body 24a and an elongated plate-shaped tray lid 24b. The tray body 24a has a plurality of shim pockets 24d provided so as to be continuously arranged along the longitudinal direction, and each shim pocket 24d is used to correct the non-uniformity of the static magnetic field in the imaging space. A required number of magnetic shims 24c are stored.

Returning to FIG. 2, the container 25 houses the main coil 21, the shield coil 22, the shim tray guide 23, and the shim tray 24 inside. Specifically, the container 25 is formed in a substantially cylindrical shape having a hollow portion between the inner peripheral portion and the outer peripheral portion, and the main coil 21, the shield coil 22, the shim tray guide 23, and the shim tray guide 23 are formed in the hollow portion. It houses the shim tray 24.

For example, the container 25 uses two substantially cylindrical members having the same axial length but different diameters as the inner peripheral portion and the outer peripheral portion, and the inner peripheral portion is arranged inside the outer peripheral portion. It is formed by sealing both ends in the axial direction with an annular plate member. In this case, for example, the main coil 21, the shield coil 22, and the shim tray guide 23 are arranged between the inner peripheral portion and the outer peripheral portion, and the shim tray 24 in which the magnetic material shim 24c is stored is the shim tray guide. After being inserted into 23, both ends of each of the inner peripheral portion and the outer peripheral portion are sealed by an annular plate member.

The container 25 is provided with an inflow port 25a and an outflow port 25b as a distribution port for circulating the refrigerant, and the inside of the container 25 is filled with the refrigerant through the inflow port 25a. Here, the refrigerant is, for example, an insulating liquid such as Fluorinert.

Specifically, the inflow port 25a is provided on the end face on one end side in the axial direction of the container 25, and the outlet 25b is provided on the end face on the other end side in the axial direction of the container 25. For example, the container 25 is provided with a plurality of inlets 25a and a plurality of outlets 25b at equal intervals around the axis of each coil. Here, the inflow port 25a is connected to a cooling device (not shown) via a pipe, and by allowing the refrigerant 26 supplied from the cooling device to flow into the inside of the container 25, the refrigerant is introduced into the inside of the container 25. 26 is filled. On the other hand, the outlet 25b is also connected to the cooling device via a pipe, and the refrigerant 26 extruded from the inside of the container 25 is discharged and returned to the cooling device. As a result, each coil contained in the main coil 21 and the shield coil 22 can be directly cooled by the refrigerant 26 filled in the container 25 without using a hollow conductor.

Further, in the present embodiment, in addition to such a configuration, by further providing a gap between the patterns of each coil included in the main coil 21 and the shield coil 22, the flow path of the refrigerant 26 is provided between the coils. Is formed. As a result, each coil contained in each of the main coil 21 and the shield coil 22 can be cooled more directly by the refrigerant 26 filled in the container 25.

In general, in an MRI apparatus, in order to firmly integrate a plurality of gradient magnetic field coils, a resin is impregnated between the gradient magnetic field coils to fix each gradient magnetic field coil. However, in the present embodiment, the gradient magnetic field coils are fixed. Since the flow path of the refrigerant 26 is formed between the gradient magnetic field coils, the resin is not impregnated.

Specifically, in the present embodiment, a groove serving as a flow path of the refrigerant 26 is formed in each of the patterns of the X coil and the Y coil included in the main coil 21 and the shield coil 22.

4 and 5 are views showing an example of a groove formed in the X coil 21x included in the main coil 21 according to the first embodiment. Here, FIG. 4 shows one of a plurality of spiral patterns included in the X coil 21x, and the spiral patterns arranged along the circumferential surface of the X coil 21x are developed in a plane. It shows the situation of the case. Further, FIG. 5 shows a cross section along the thickness direction of the portion where the groove included in the pattern of the X coil 21x is formed.

For example, as shown in FIG. 4, a plurality of grooves 21a are formed in the X coil 21x at equal intervals along the circumferential direction (vertical direction in FIG. 4) of the X coil 21x. Here, each groove is formed along the axial direction of the X coil 21x, that is, the Z-axis direction, and each groove is formed so as to be parallel to each other. Further, for example, as shown in FIG. 5, each groove is formed so as to have a depth of about half the thickness of the pattern of the X coil 21x.

Here, the X coil 21x included in the main coil 21 has been described as an example, but the same applies to the Y coil 21y included in the main coil 21, the X coil 22x and the Y coil 22y included in the shield coil 22. A plurality of grooves are formed in the coil.

Then, in the present embodiment, in each of the main coil 21 and the shield coil 22, the X coil, the Y coil, and the Z coil laminated in the radial direction are fixed and integrated with the insulating member arranged between the layers of the respective coils. Has been done.

FIG. 6 is a diagram showing an arrangement example of the X coil, the Y coil, and the Z coil in the gradient magnetic field coil unit 20 according to the first embodiment. Here, FIG. 6 shows a cross section orthogonal to the central axis of the gradient magnetic field coil unit 20, and is a part of each pattern of the X coil 21x, the Y coil 21y, and the Z coil 21z included in the main coil 21, and One shim tray guide 23 is shown. In FIG. 6, the upper side shows the outer peripheral side of the gradient magnetic field coil unit 20, and the lower side shows the inner peripheral side of the gradient magnetic field coil unit 20.

For example, as shown in FIG. 6, the X coil 21x, the Y coil 21y, and the Z coil 21z included in the main coil 21 are laminated in the radial direction. A cylindrical insulating member 27a is arranged between the X coil 21x and the Y coil 21y, and both coils are firmly fixed to the insulating member 27a with an adhesive or the like. Further, a cylindrical insulating member 27b is also arranged between the Y coil 21y and the Z coil 21z, and both coils are firmly fixed to the insulating member 27b with an adhesive or the like.

According to such a configuration, the groove 21a and the insulating member 27a formed in the X coil 21x provide a gap extending along the axial direction of the main coil 21 between the X coil 21x and the Y coil 21y. become. Further, the groove 21b and the insulating member 27b formed in the Y coil 21y provide a gap extending along the axial direction of the main coil 21 between the Y coil 21y and the Z coil 21z. As a result, when the container 25 is filled with the refrigerant 26, the refrigerant 26 flows into the respective gaps. That is, a flow path of the refrigerant 26 is formed between the X coil 21x and the Y coil 21y, and between the Y coil 21y and the Z coil 21z.

Here, since the saddle coil normally used as the X coil and the Y coil is manufactured individually, it is easy to form a groove, but the solenoid coil used as the Z coil has a cylindrical base. Since it is often made by winding a flat copper wire around a material or other gradient magnetic field coil, it may be difficult to provide a groove in manufacturing.

Therefore, in the present embodiment, the Z coil is not formed with a groove, and instead, a spacer is arranged between the Z coil and the member laminated on the Z coil, thereby further flowing the refrigerant 26. There is a gap that serves as a road.

For example, as shown in FIG. 6, two spacers 28 are arranged between the Z coil 21z included in the main coil 21 and the shim tray guide 23 laminated on the Z coil 21z. Here, each spacer 28 is arranged between the Z coil 21z and the shim tray guide 23 so as to extend along the axial direction of the main coil 21, and the Z coil 21z and the shim tray guide 23 are adhered to each other. It is firmly fixed with an agent or the like.

According to such a configuration, the two spacers 28 provide a gap extending along the axial direction of the main coil 21 between the Z coil 21z and the shim tray guide 23. As a result, when the container 25 is filled with the refrigerant 26, the refrigerant 26 flows into the gap. That is, a flow path of the refrigerant 26 is formed between the Z coil 21z and the shim tray guide 23. As described above, the flow path of the refrigerant 26 is formed between the Z coil 21z and the shim tray guide 23, so that the heat generated from the Z coil 21z is stored in the shim tray guide 23 and the shim tray guide 23. It becomes possible to prevent transmission to the body shim 24c. Although not shown in FIG. 6, the side on which the shield coil 22 is arranged is configured in the same manner as the side on which the main coil 21 is arranged.

Here, in the present embodiment, the width of the groove formed in the pattern of the X coil and the Y coil described above and the width of the spacer arranged between the Z coil and the shim tray guide 23 are the pressures of the refrigerant 26. It is decided according to the loss. For example, the width of the groove and the width of the spacer are determined according to the performance of the pump included in the cooling device that supplies the refrigerant 26. More specifically, for example, the width of the groove and the spacer is determined so that the pressure loss of the refrigerant 26 flowing inside the container 25 is smaller than the maximum allowable pressure of the pump.

Further, in the present embodiment, the gradient magnetic field coil unit 20 further includes a support member (also referred to as a bobbin) 29 formed in a cylindrical shape, and the X coil 21x included in the main coil 21 is the support member 29. It is fixed to the outer peripheral part. Here, the support member 29 is made of a material that is tougher, has higher rigidity, and has insulating properties than the insulating members 27a and 27b described above.

Then, for example, the X coil 21x is firmly fixed to the support member 29 by being embedded in the fixing groove formed on the outer peripheral surface of the support member 29. For example, the X coil 21x may be firmly fixed to the outer peripheral surface of the support member 29 with an adhesive or the like instead of being fixed by the fixing groove. Alternatively, the X coil 21x may be embedded in a fixing groove formed on the outer peripheral surface of the support member 29, and may be fixed to the fixing groove with an adhesive.

As described above, in the first embodiment, each coil contained in the main coil 21 and the shield coil 22 can be directly cooled by the refrigerant 26 filled in the container 25 without using the hollow conductor. .. Therefore, according to the first embodiment, it is possible to directly cool each coil contained in each of the main coil 21 and the shield coil 22 with a structure that is structurally and easily manufactured as compared with the case of using a hollow conductor. can. Further, by directly cooling the entire main coil 21 and the shield coil 22, higher cooling performance than when a hollow conductor is used can be realized.

Further, in the first embodiment, the X coil, the Y coil, and the Z coil included in the main coil 21 and the shield coil 22 are firmly fixed to the insulating member, respectively, and the Z coil and the shim tray guide 23 are provided. Each is firmly fixed to the spacer. Therefore, according to the first embodiment, the main coil 21 and the shield coil 22 can be firmly integrated without being impregnated with the resin. Further, in the first embodiment, the X coil 21x of the main coil 21 which is the innermost layer of the gradient magnetic field coil unit 20 is fixed to the support member 29, so that the entire gradient magnetic field coil unit 20 is more firmly integrated. be able to.

Further, in the first embodiment, the width of the groove formed in the pattern of the X coil and the Y coil included in the main coil 21 and the shield coil 22 and the width of the groove are arranged between the Z coil and the shim tray guide 23. The width of the spacer is determined according to the pressure loss of the refrigerant 26. Therefore, according to the first embodiment, the pressure loss of the refrigerant 26 can be adjusted by changing the width of the groove and the spacer.

For example, the width of the groove formed in the pattern of the X coil and the Y coil and the width of the spacer arranged between the Z coil and the shim tray guide 23 are determined according to the properties of each coil. May be good. For example, the X coil is often used to generate a gradient magnetic field in the lead-out direction, and is considered to generate more heat than the Y coil. Therefore, for example, the width of the groove formed in the X coil may be larger than the width of the groove formed in the Y coil.

Although the first embodiment has been described above, the configuration of the gradient magnetic field coil unit 20 described above can be implemented by appropriately modifying a part thereof. Therefore, in the following, some modifications according to the first embodiment will be described as other embodiments. In each of the embodiments described below, the points different from those described above will be mainly described, and detailed description of the contents common to the embodiments described above will be omitted.

(Second embodiment)
For example, in the above-described embodiment, the case where the X coil, the Y coil, and the Z coil are fixed to the insulating member has been described, but the embodiment is not limited to this. For example, instead of using the insulating member, a support member similar to the support member 27 to which the X coil 21x of the main coil 21 is fixed may be used in the first embodiment.

FIG. 7 is a diagram showing an arrangement example of the X coil, the Y coil, and the Z coil in the gradient magnetic field coil unit 20 according to the second embodiment. Here, FIG. 7 shows a cross section orthogonal to the central axis of the gradient magnetic field coil unit 20, similar to FIG.

For example, as shown in FIG. 7, in the present embodiment, a support member 29a formed in a cylindrical shape is arranged between the X coil 21x and the Y coil 21y included in the main coil 21. Further, a support member 29b formed in a cylindrical shape is also arranged between the Y coil 21y and the Z coil 21z. Here, each support member is made of a material having tougher, more rigid, and insulating properties as compared with the above-mentioned insulating member, like the support member 27 to which the X coil 21x of the main coil 21 is fixed. Has been done.

Then, in the present embodiment, the Y coil 21y is firmly fixed to the support member 29a by being embedded in the fixing groove formed on the outer peripheral surface of the support member 29a. Further, the Z coil 21z is also firmly fixed to the support member 29b by being embedded in the fixing groove formed on the outer peripheral surface of the support member 29b. For example, the Y coil 21y and the Z coil 21z may be firmly fixed to the outer peripheral surface of each support member with an adhesive or the like instead of being fixed by the fixing groove. Alternatively, the Y coil 21y and the Z coil 21z may be embedded in a fixing groove formed on the outer peripheral surface of each support member, and may be fixed to the fixing groove with an adhesive.

According to such a configuration, the groove 21a and the support member 29a formed in the X coil 21x provide a gap extending along the axial direction of the main coil 21 between the X coil 21x and the Y coil 21y. become. Further, the groove 21b and the support member 29b formed in the Y coil 21y provide a gap extending along the axial direction of the main coil 21 between the Y coil 21y and the Z coil 21z. As a result, also in the present embodiment, as in the first embodiment, the flow path of the refrigerant 26 is formed between the X coil 21x and the Y coil 21y and between the Y coil 21y and the Z coil 21z. Will be. Although not shown in FIG. 7, the side on which the shield coil 22 is arranged is configured in the same manner as the side on which the main coil 21 is arranged.

As described above, in the second embodiment, not only the X coil but also the Y coil and the Z coil are fixed to the support member, so that the main coil 21 and the shield coil 22 can be fixed more firmly.

(Third embodiment)
Further, for example, in the above-described embodiment, an example in which the spacer is arranged only between the Z coil included in the main coil 21 and the shield coil 22 and the shim tray guide 23 has been described. Not limited to. For example, spacers may be further arranged between the X coil and the Y coil, and between the Y coil and the Z coil.

FIG. 8 is a diagram showing an arrangement example of the X coil, the Y coil, and the Z coil in the gradient magnetic field coil unit 20 according to the third embodiment. Here, FIG. 8 shows a cross section orthogonal to the central axis of the gradient magnetic field coil unit 20, similar to FIG.

For example, as shown in FIG. 8, in the present embodiment, as in the example shown in FIG. 7, a support member formed in a cylindrical shape between the X coil 21x and the Y coil 21y included in the main coil 21. 29a is arranged. Further, a support member 29b formed in a cylindrical shape is also arranged between the Y coil 21y and the Z coil 21z.

Further, in the present embodiment, two spacers 28a are further arranged between the X coil 21x included in the main coil 21 and the support member 29a so as to sandwich the groove 21a formed in the X coil 21x. There is. Here, each spacer 28a is arranged so as to extend along the axial direction of the main coil 21 between the X coil 21x and the support member 29a, and the X coil 21x and the support member 29a are arranged such as an adhesive. It is firmly fixed with.

Further, in the present embodiment, two spacers 28b are further arranged between the Y coil 21y included in the main coil 21 and the support member 29b so as to sandwich the groove 21b formed in the Y coil 21y. ing. Here, each spacer 28b is arranged so as to extend along the axial direction of the main coil 21 between the Y coil 21y and the support member 29b, and the Y coil 21y and the support member 29b are arranged such as an adhesive. It is firmly fixed with.

According to such a configuration, the groove 21a formed in the X coil 21x, the support member 29a, and the two spacers 28a are provided between the X coil 21x and the Y coil 21y along the axial direction of the main coil 21. An extending gap will be provided. Further, the groove 21b, the support member 29b, and the two spacers 28b formed in the Y coil 21y provide a gap extending along the axial direction of the main coil 21 between the Y coil 21y and the Z coil 21z. become. As a result, also in the present embodiment, as in the first embodiment, the flow path of the refrigerant 26 is formed between the X coil 21x and the Y coil 21y and between the Y coil 21y and the Z coil 21z. Will be. Although not shown in FIG. 8, the side on which the shield coil 22 is arranged is configured in the same manner as the side on which the main coil 21 is arranged.

Here, also in this embodiment, the width of each spacer is determined according to the pressure loss of the refrigerant 26.

In the example shown in FIG. 8, an example in which a spacer is arranged between the X coil and the support member and between the Y coil and the support member has been described, but the embodiment is not limited to this. .. For example, as shown in FIG. 6, when an insulating member is used instead of the support member, FIG. 8 shows the space between the X coil and the insulating member and between the Y coil and the insulating member. Spacers may be arranged in the same manner as in the example shown.

As described above, in the third embodiment, the spacer is arranged not only between the Z coil and the shim tray guide 23, but also between the X coil and the Y coil, and between the Y coil and the Z coil. As a result, the pressure loss of the refrigerant 26 between the coils can be adjusted more flexibly, and the desired flow rate distribution can be realized more reliably.

(Fourth Embodiment)
Further, for example, in the above-described embodiment, an example in which a spacer is arranged between the Z coil included in the main coil 21 and the shield coil 22 and the shim tray guide 23 has been described. Not limited. For example, the Z coil and the shim tray guide 23 may be laminated without the spacer 28.

FIG. 9 is a diagram showing an arrangement example of the X coil, the Y coil, and the Z coil in the gradient magnetic field coil unit 20 according to the fourth embodiment. Here, FIG. 9 shows a cross section orthogonal to the central axis of the gradient magnetic field coil unit 20, similar to FIG.

For example, as shown in FIG. 9, in the present embodiment, the Z coil 21z included in the main coil 21 and the shim tray guide 23 are continuously laminated without interposing the spacer 28, and the Z coil 21z is shim. It is firmly fixed to the tray guide 23 with an adhesive or the like. On the other hand, the Z coil 22z and the shim tray guide 23 included in the shield coil 22 are also continuously laminated without a spacer, and the Z coil 21z is firmly attached to the shim tray guide 23 with an adhesive or the like. It is fixed to.

According to such a configuration, as described above, a plurality of shim tray guides 23 are arranged at equal intervals along the circumferential direction of the main coil 21, so that the adjacent shim tray guides 23 can be used to make the main coil 21. A gap extending along the axial direction of each coil is provided between the Z coil 21z and the Z coil 22z of the shield coil 22. As a result, a flow path for the refrigerant 26 is formed between the Z coil 21z of the main coil 21 and the Z coil 22z of the shield coil 22.

Thus, in the fourth embodiment, the Z coil and the shim tray guide 23 are laminated without the spacer 28, so that the gradient magnetic field coil is directly cooled in a structurally and manufacturingly easier configuration. become able to.

(Fifth Embodiment)
Further, for example, in the above-described embodiment, an example in which a plurality of grooves are formed at equal intervals along the circumferential direction of each coil in the X coil and the Y coil has been described, but the embodiment is limited to this. do not have. For example, in the X coil and the Y coil, a plurality of grooves may be formed so as to be dense at locations where heat generation is large in each pattern.

FIG. 10 is a diagram showing an example of a groove formed in the X coil 21x included in the main coil 21 according to the fifth embodiment. Here, FIG. 10 shows one of the plurality of spiral patterns included in the X coil 21x, as in FIG. 4.

For example, in a spiral pattern as shown in FIG. 10, the conductors of the pattern are usually densely packed in the central portion, and the central portion generates the largest amount of heat. Therefore, in the present embodiment, in the X coil 21x, a plurality of grooves 21c are concentrated around the X coil 21x in the circumferential direction (vertical direction in FIG. 10) of the X coil 21x. It is formed so that the number of lines passing through the central portion is larger than the number of lines passing through the central portion. Here, each groove is formed along the Z-axis direction, and each groove is formed so as to be parallel to each other.

As described above, in the fifth embodiment, in the X coil and the Y coil, the X coil and the Y coil are made more efficient by forming a plurality of grooves so as to be dense at the place where the heat generation in each pattern is large. You will be able to cool well.

(Sixth Embodiment)
Further, for example, in the above-described embodiment, an example in which a plurality of grooves are formed along the Z-axis direction in the X coil and the Y coil included in the main coil 21 and the shield coil 22 has been described. Is not limited to this. For example, in the X coil and the Y coil, a plurality of grooves may be formed along a direction oblique to the Z axis direction.

FIG. 11 is a diagram showing an example of a groove formed in the X coil 21x included in the main coil 21 according to the sixth embodiment. Here, FIG. 11 shows one of the plurality of spiral patterns included in the X coil 21x, as in FIG. 4.

For example, as shown in FIG. 11, in the present embodiment, a plurality of grooves 21d are formed in the X coil 21x along a direction oblique to the Z-axis direction. That is, in the present embodiment, it can be said that the X coil 21x is formed along a diagonal direction with respect to the circumferential direction (vertical direction in FIG. 11). Here, each groove may be formed so as to be parallel to each other, or as in the example shown in FIG. 10, the number of grooves passing through the central portion as compared with the number of existing grooves passing through the peripheral portion of the X coil 21x. May be formed so as to increase.

As described above, in the sixth embodiment, in the X coil and the Y coil, the pattern is formed in a spiral shape by forming a plurality of grooves along the diagonal direction with respect to the Z axis direction. Even in such a case, the refrigerant filled between the patterns can easily flow, and the X coil and the Y coil can be cooled more efficiently.

(7th Embodiment)
Further, for example, in the above-described embodiment, an example will be described in which, in the container 25 of the gradient magnetic field coil unit 20, a plurality of inlets 25a and a plurality of outlets 25b are provided around the axis of each coil at equal intervals. However, for example, the positions where the inlet 25a and the outlet 25b are provided may be determined more specifically from the viewpoint of cooling efficiency.

As described above, in the spiral pattern as included in the X coil and the Y coil, the conductors of the pattern are usually densely packed in the central portion, and the central portion generates the largest amount of heat. Therefore, in the present embodiment, the inflow port 25a and the outflow port 25b are provided at the same positions as the central portion of the spiral pattern in the circumferential direction of the X coil and the Y coil.

FIG. 12 is a diagram showing an arrangement example of the inflow port 25a and the outflow port 25b in the container 25 according to the seventh embodiment. Here, FIG. 12 shows the end surface of the container 25 on the one end side in the axial direction provided with the inflow port 25a and the outflow port 25b.

Specifically, in the X-coil, in order to generate a gradient magnetic field along the X-axis set in the horizontal direction orthogonal to the central axis of the gradient magnetic field coil unit 20, at least two spiral patterns are formed on the central axis. It is arranged so as to face each other in the horizontal direction across the. Further, in the Y coil, at least two spiral patterns sandwich the central axis in order to generate a gradient magnetic field along the Y axis set in the vertical direction orthogonal to the central axis of the gradient magnetic field coil unit 20. They are arranged so as to face each other in the vertical direction.

Therefore, for example, as shown in FIG. 12, inside the container 25, an angle is set around the axis starting from one end in the horizontal direction in a plane (XY plane) orthogonal to the central axis of the X coil and the Y coil. By definition, the center of the spiral pattern will be located at 0 °, 90 °, 180 °, and 270 °. As a result, for example, heat generation increases in the portion shown by the broken line rectangle in FIG. 12.

From this, in the present embodiment, on the end surface on one end side in the axial direction of the container 25, the positions where the central portion of the spiral pattern is arranged inside the container 25 (0 °, 90 °, 180 ° described above, An inflow port 25a is provided every 90 ° around the axes of the X coil and the Y coil (at the position of 270 °). Further, on the end surface on the other end side in the axial direction of the container 25, an outflow port 25b is provided at the same position as each inflow port 25a in the circumferential direction of the X coil and the Y coil. As a result, the refrigerant can flow in from one side of the container 25 and outflow from the other side with respect to the portion where the central portion of the spiral pattern is arranged, and the portion where heat generation is large can be formed. It will be possible to focus on cooling.

As described above, in the seventh embodiment, the inlet 25a and the outlet 25b are more efficiently provided at the same positions as the central portion of the spiral pattern in the circumferential direction of the X coil and the Y coil. The X coil and the Y coil can be cooled.

In the first to seventh embodiments described above, an example in which the gradient magnetic field coil unit 20 is configured as an ASGC has been described, but the embodiment is not limited to this.

For example, the gradient magnetic field coil unit 20 may be an NSGC (Non-Shielded Gradient Coil) having no shield coil. In that case, for example, the shield coil may be arranged on the outer peripheral side of the gradient magnetic field coil unit 20 separately from the gradient magnetic field coil unit 20, or may be housed in the cooling container of the static magnetic field magnet 1. May be.

Further, in the first to seventh embodiments described above, the shim tray guide 23 is arranged between the inner peripheral portion and the outer peripheral portion of the container 25, and the shim tray 24 in which the magnetic material shim 24c is stored is shim. An example has been described in which both ends of the inner peripheral portion and the outer peripheral portion are sealed by an annular plate member after being inserted into the tray guide 23, but the embodiment is not limited to this.

For example, the shim tray guide 23 and the container 25 are configured so that the shim tray 24 can be inserted into the shim tray guide 23 after both ends of the inner peripheral portion and the outer peripheral portion of the container 25 are sealed by an annular plate member. May be. In this case, for example, in the annular plate member arranged at both ends of the container 25, the opening of the shim tray guide 23 (the opening into which the shim tray 24 is inserted) is located at the position where the shim tray guide 23 is arranged. ) Is provided with a through hole having substantially the same shape. Further, the shim tray guide 23 is formed so as to have substantially the same length as the axial direction of the container 25, and the opening is positioned at the same position as the through hole provided in the annular plate member of the container 25. Be placed. In this case, the shim tray guide is in a state where the opening of the shim tray guide 23 and the through hole provided in the annular plate member of the container 25 are continuous so that the inside of the container 25 is sealed. The end portion of the 23 and the annular plate member are closely fixed.

The word "processor" used in the description of each of the above-described embodiments is, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), or an integrated circuit for a specific application (Application Specific Integrated Circuit: ASIC). , Circuits such as programmable logic devices (eg, Simple Programmable Logic Device (SPLD), Complex Programmable Logic Device (CPLD), and Field Programmable Gate Array (FPGA)). Means. Here, instead of storing the program in the storage circuit, the program may be configured to be directly embedded in the circuit of the processor. In this case, the processor realizes the function by reading and executing the program embedded in the circuit. Further, each processor of the present embodiment is not limited to the case where each processor is configured as a single circuit, and a plurality of independent circuits may be combined to be configured as one processor to realize its function. good.

Here, the program executed by the processor is provided by being incorporated in a ROM (Read Only Memory), a storage circuit, or the like in advance. This program is a file in a format that can be installed or executed on these devices, such as CD (Compact Disk) -ROM, FD (Flexible Disk), CD-R (Recordable), DVD (Digital Versatile Disk), etc. It may be recorded and provided on a computer-readable storage medium. Further, this program may be stored on a computer connected to a network such as the Internet, and may be provided or distributed by being downloaded via the network. For example, this program is composed of modules including each of the above-mentioned functional parts. As actual hardware, the CPU reads a program from a storage medium such as a ROM and executes the program, so that each module is loaded on the main storage device and generated on the main storage device.

According to at least one embodiment described above, the gradient magnetic field coil can be directly cooled with a structure that is structurally and easily manufactured.

Although some embodiments of the present invention 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 embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and variations thereof are included in the scope of the invention described in the claims and the equivalent scope thereof, as are included in the scope and gist of the invention.

100 MRI device 20 gradient magnetic field coil unit 21 main coil 21x X coil 21y Y coil 21z Z coil 22 shield coil 22x X coil 22y Y coil 22z Z coil 25 container 25a inlet 25b outlet 26 refrigerant 27a, 27b insulation member 28 spacer 29 Support member

Claims (13)

A gradient magnetic field coil formed in a substantially cylindrical shape that generates a gradient magnetic field,
A container for accommodating the gradient magnetic field coil inside, and
Equipped with
The container is provided with a distribution port through which the refrigerant flows, and the inside of the container is filled with the refrigerant through the distribution port.
In the pattern of the gradient magnetic field coil, a flow path of the refrigerant is formed along the substantially cylindrical axial direction of the gradient magnetic field coil or along a direction oblique to the axial direction. ,
Magnetic resonance imaging device. The container is provided with a plurality of the flow ports at equal intervals around the axis of the gradient magnetic field coil.
The magnetic resonance imaging apparatus according to claim 1. The gradient magnetic field coil contains a spiral pattern arranged along the circumferential surface of the gradient magnetic field coil.
The flow port is provided at the same position as the center of the pattern in the circumferential direction of the gradient magnetic field coil.
The magnetic resonance imaging apparatus according to claim 1 or 2. A groove serving as a flow path for the refrigerant is formed in the pattern of the gradient magnetic field coil.
The magnetic resonance imaging apparatus according to any one of claims 1 to 3. The groove is formed along the substantially cylindrical axial direction of the gradient magnetic field coil.
The magnetic resonance imaging apparatus according to claim 4. A plurality of the grooves are formed so as to be dense in the place where the heat generation is large in the pattern.
The magnetic resonance imaging apparatus according to claim 5. The groove is formed along a direction oblique to the axial direction of the substantially cylindrical shape of the gradient magnetic field coil.
The magnetic resonance imaging apparatus according to claim 5 or 6. The width of the groove is determined according to the pressure loss of the refrigerant.
The magnetic resonance imaging apparatus according to any one of claims 4 to 7. Further provided with a support member formed in a cylindrical shape,
The gradient magnetic field coil is fixed to the outer peripheral portion of the support member.
The magnetic resonance imaging apparatus according to any one of claims 1 to 8. Further comprising a spacer disposed between the gradient magnetic field coil and a member laminated on the gradient magnetic field coil to form a flow path for the refrigerant.
The magnetic resonance imaging apparatus according to any one of claims 1 to 9. The width of the spacer is determined according to the pressure loss of the refrigerant.
The magnetic resonance imaging apparatus according to claim 10. With the plurality of the gradient magnetic field coils,
Each gradient magnetic field coil is laminated in the radial direction, and is fixed and integrated with an insulating member arranged between layers.
The magnetic resonance imaging apparatus according to any one of claims 1 to 11. The refrigerant is an insulating liquid.
The magnetic resonance imaging apparatus according to any one of claims 1 to 12.

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