Reception coil unit, medical image diagnostic system, and coil cover

Abstract

To provide a reception coil unit which can release heat from between the reception coil unit and an analyte, a medical image diagnostic system, and a coil cover.SOLUTION: A reception coil unit comprises: coil elements for receiving a nuclear magnetic-resonance signal of an analyte; a flexible coil cover for covering the periphery of the coil elements; and a plurality of passage formation members arranged on an outer surface in contact with the analyte, of the coil cover, in which first passages extending in a first direction and second passages extending in a second direction different from the first direction are formed between the analyte and the coil cover.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a receiving coil unit, a medical image diagnostic system, and a coil cover.

Background Art

[0002] When imaging a subject by a magnetic resonance imaging (MRI) device, the subject is placed in the imaging space of the gantry together with the table of the bed device. At that time, in order to obtain an image of the imaging part (for example, chest or abdomen) of the subject, a receiving coil unit such as an RF (Radio Frequency) coil for receiving a nuclear magnetic resonance (NMR) signal is used.

[0003] For example, Patent Document 1 discloses an RF coil unit for a child. This RF coil unit includes a support portion that supports the back of the subject and is provided with coil elements, and the surface of the support portion that contacts the back of the subject is composed of a cushion material having irregularities.

[0004] Patent Document 2 discloses an RF coil set including an RF coil and a cushioning material for cushioning the RF coil.

[0005] Patent Document 3 discloses a coil in which a plurality of receiver coils are arranged on a flexible blanket.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] By the way, the receiving coil unit is attached in close contact with the subject in order to obtain high sensitivity. Therefore, it is difficult to release the heat from the subject, and the structure is such that heat is likely to be trapped.

[0008] In the RF coil unit described in Patent Document 1, since the cushioning material and the subject are continuously in close contact in the plane direction, it is difficult to release heat.

[0009] In the RF coil described in Patent Document 2, since a sheet-like cushioning material is interposed between the subject and the RF coil, it is difficult to release heat.

[0010] In the coil described in Patent Document 3, since it is composed of a blanket, it adheres to the subject due to its flexibility, traps heat, and it is difficult to release heat.

[0011] The present invention has been made in view of such circumstances, and an object thereof is to provide a receiving coil unit, a medical image diagnostic system, and a coil cover that enable heat to escape from between the subject and the receiving coil unit.

Means for Solving the Problems

[0012] The receiving coil unit according to the first aspect includes a coil element that receives a nuclear magnetic resonance signal of a subject, a flexible coil cover that covers the periphery of the coil element, and a plurality of passage forming members disposed on the outer surface of the coil cover that contacts the subject, the plurality of passage forming members forming a first passage extending in a first direction and a second passage extending in a second direction different from the first direction between the subject and the coil cover.

[0013] In the receiving coil unit according to the second aspect, in the first aspect, the passage forming member is composed of one kind of material selected from the group consisting of non-magnetic metal, resin, closed-cell foam, and rubber, or a combination of two or more kinds of materials.

[0014] In the receiving coil unit of the third aspect, in the first aspect or the second aspect, the passage forming member has a plate-like shape.

[0015] In the receiving coil unit of the fourth aspect, in any one of the first aspect to the third aspect, the passage forming member is configured to be deformable.

[0016] In the receiving coil unit of the fifth aspect, in any one of the first aspect to the fourth aspect, the passage forming member is composed of two or more members having different shapes.

[0017] In the receiving coil unit of the sixth aspect, in any one of the first aspect to the fifth aspect, the passage forming member has a shape in which a groove is formed on the side of the subject.

[0018] In the receiving coil unit of the seventh aspect, in any one of the first aspect to the sixth aspect, the passage forming member has a hollow structure.

[0019] In the receiving coil unit of the eighth aspect, in any one of the first aspect to the seventh aspect, it includes a heat source connected to the coil element, and the passage forming member is arranged corresponding to the heat source.

[0020] In the receiving coil unit of the ninth aspect, in any one of the first aspect to the seventh aspect, it includes a heat source connected to each of the plurality of coil elements, and the passage forming member is arranged at a position corresponding to the plurality of heat sources.

[0021] In the receiving coil unit of the tenth aspect, in the eighth aspect or the ninth aspect, the passage forming member is composed of a heat insulating material.

[0022] In the receiving coil unit of the eleventh aspect, in the fourth aspect, a spacer is provided between the passage forming member and the outer surface of the coil cover.

[0023] In the receiving coil unit according to the 12th aspect, in any one of the 1st to 11th aspects, a plurality of passage forming members are arranged in a lattice pattern.

[0024] In the receiving coil unit according to the 13th aspect, in any one of the 1st to 12th aspects, the coil cover is bag-shaped.

[0025] The medical imaging diagnosis system according to the 14th aspect includes a receiving coil unit according to any one of the 1st to 13th aspects and a magnetic resonance imaging apparatus that processes the nuclear magnetic resonance signal received by the receiving coil unit.

[0026] The coil cover according to the 15th aspect covers the periphery of a coil element that receives the nuclear magnetic resonance signal of a subject, and is a plurality of passage forming members arranged on the outer surface of the coil cover that contacts the subject, and forms a first passage extending in a first direction and a second passage extending in a second direction different from the first direction between the subject and the coil cover. It is provided with a plurality of passage forming members.

Effect of the Invention

[0027] According to the present invention, it is possible to allow heat to escape from between the subject and the receiving coil unit to the outside.

Brief Description of the Drawings

[0028]

Figure 1

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Figure 10

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Figure 17

Figure 18

DETAILED DESCRIPTION OF THE INVENTION

[0029] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description and the accompanying drawings, the same reference numerals are given to the same components, and redundant descriptions are omitted. Also, in the following embodiments, when a plurality of components are exemplified, it can be interpreted as including at least one of the plurality of components.

[0030] As shown in FIG. 1, the medical image diagnostic system 10 of the embodiment is a magnetic resonance imaging apparatus (hereinafter referred to as an MRI apparatus) 20, and includes a reception coil unit 50.

[0031] 〔MRI Apparatus〕 The MRI apparatus 20 is installed in an examination room of an image diagnostic facility. In the examination room, the subject is placed on the top plate 34 of the table 32 of the bed apparatus 30, and then is conveyed toward the static magnetic field generating magnet 102 of the MRI apparatus 20 by the movement of the table 32.

[0032] The MRI apparatus 20 has a static magnetic field generating magnet 102. The static magnetic field generating magnet 102 has a cylindrical shape, has an upper imaging space 24 at the center of the cylindrical shape, and the table 32 moves into this imaging space 24. Gantry monitors 26 are installed on both the left and right sides of the static magnetic field generating magnet 102. The gantry monitor 26 also functions as an operation panel.

[0033] Note that the three-dimensional coordinate system shown in FIG. 1 shows an example of the definition of directions in the MRI apparatus 20. The X-axis, Y-axis, and Z-axis of the three-dimensional coordinate system are examples and are not limited thereto. For ease of understanding in the following description, the X-axis, Y-axis, and Z-axis in the MRI apparatus 20 are defined in the same direction in any figure. As an example of the three-dimensional coordinate system, the Z-axis direction is the static magnetic field direction, the Y-axis direction is the vertical direction of the subject, and is the same vertical direction as the gravitational direction. The X-axis direction is the left-right direction of the subject and is the horizontal direction.

[0034] FIG. 2 is a schematic diagram showing the internal configuration of the MRI apparatus 20.

[0035] As shown in FIGS. 1 and 2, the MRI apparatus 20 includes a static magnetic field generating magnet 102, a gradient magnetic field coil 104, and a transmission coil 106.

[0036] The static magnetic field generating magnet 102 generates a uniform static magnetic field in the imaging space 24 where the subject 100 is placed. The gradient magnetic field coil 104 generates a gradient magnetic field in the imaging space 24. The transmission coil 106 generates a high-frequency magnetic field in the imaging space 24 for generating a nuclear magnetic resonance signal (NMR (Nuclear Magnetic Resonance) signal) (hereinafter referred to as an NMR signal) in the atomic nuclei of the atoms constituting the tissue of the subject 100.

[0037] The receiving coil unit 50 is attached to the chest and abdomen of the subject 100 using a belt 36 provided in the bed apparatus 30 on the top plate 34. By moving the table 32 on which the subject 100 is placed into the imaging space 24, the examination site (imaging target site) of the subject 100 is positioned at the center of the static magnetic field in the imaging space 24. The receiving coil unit 50 is attached to the subject 100 and detects the NMR signal generated from the subject 100.

[0038] The sequencer 108 sends commands to the high-frequency transmitter 110 and the gradient magnetic field power supply 112 according to an imaging sequence (pulse sequence), and appropriately amplified signals are sent to the transmission coil 106 or the gradient magnetic field coil 104 respectively.

[0039] The signal sent to the transmission coil 106 is applied to the subject 100 as a pulsed high-frequency magnetic field (RF pulse) via the transmission coil 106. The NMR signal generated from the subject 100 is detected by the coil element 52 of the receiving coil unit 50, and demodulation is performed by the receiver 114.

[0040] Note that the gradient magnetic field coil 104 is composed of gradient magnetic field coils in three directions of X, Y, and Z, and generates gradient magnetic fields respectively according to signals from the gradient magnetic field power supply 112.

[0041] The nuclear magnetic resonance frequency (detection reference frequency f0) used as the reference for detection in the receiver 114 is set by the sequencer 108. The sequencer 108 controls so that each part operates at a programmed timing and intensity. Among the programs, those that particularly describe the timing and intensity of RF pulses, gradient magnetic fields, and signal reception are called pulse sequences.

[0042] Although various pulse sequences are known according to the purpose, detailed descriptions thereof are omitted here.

[0043] The control unit 116 controls the operation of the MRI apparatus 20 via the sequencer 108, receives the signal detected by the receiver 114, and performs various signal processes such as image reconstruction. Note that the receiver 114 quadrature phase-detects the received signal (NMR signal), which is an analog wave, at the set detection reference frequency f0, performs AD (analog-digital) conversion, and then transmits it to the control unit 116. This data is also referred to as the received signal or measurement data.

[0044] The control unit 116 receives various instruction inputs from the operation unit 118 and comprehensively controls each part of the MRI apparatus 20. Further, the control unit 116 performs processes such as inverse Fourier transform of the received signal in the spatial frequency domain received via the sequencer 108 to convert it into an image in the real space, and generates an MRI image.

[0045] The control unit 116 is realized by a general-purpose computer such as a personal computer or a microcomputer. The control unit 116 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and an input / output interface, etc.

[0046] In the control unit 116, various programs such as control programs stored in the ROM are expanded in the RAM, and the programs expanded in the RAM are executed by the CPU. As a result, the functions of each part of the MRI apparatus 20 are realized, and various arithmetic processes and control processes are executed via the input / output interface.

[0047] The operation unit 118 includes a mouse, a keyboard, a gantry monitor 26, etc., and the gantry monitor 26 functions as a part of a GUI (Graphical User Interface) that receives inputs from imaging staff.

[0048] When the imaging staff operates the operation unit 118, inputs such as startup, stop (including temporary stop), selection of pulse sequence, imaging conditions, and processing conditions of the MRI apparatus 20 are made.

[0049] 〔Receiving Coil Unit of Embodiment〕 The receiving coil unit 50 has a blanket shape, and a structure that is thinner, lighter, and more flexible than an integrally molded type is applied. This receiving coil unit 50 can be deformed according to the physique of the subject 100, enabling imaging of various examination sites. Note that the receiving coil unit 50 is an example of the receiving coil unit of the present invention.

[0050] FIG. 3 is an exploded perspective view schematically showing the configuration of the receiving coil unit 50. As shown in FIG. 3, the receiving coil unit 50 includes a plurality of coil elements 52, a plurality of signal processing circuits 54 which are electrical components connected to each of the plurality of coil elements 52, and a coil cover 56.

[0051] The coil element 52 functions as a detector (sensor) for receiving NMR signals. The coil element 52 has, for example, a ring shape with a diameter of about 10 cm to 15 cm. It is two-dimensionally arranged inside the coil cover 56 of the coil element 52. The receiving coil unit 50 in this example is multi-channeled by including 24 coil elements 52. Note that the number and arrangement of the coil elements 52 are not limited to the example in FIG. 3. The coil element 52 may be configured to be deformable according to the physique of the subject 100. The coil cover 56 is an example of the coil cover of the present invention.

[0052] The signal processing circuit 54 may be composed of, for example, a module product in which an electric circuit including a plurality of circuit elements is packaged in a cubic or rectangular parallelepiped housing. The signal processing circuit 54 includes a magnetic coupling prevention circuit for preventing the intrusion of energy irradiated from the transmission coil 106 and removing the coupling between the coil element 52 and the transmission coil 106. The magnetic coupling prevention circuit is composed of a capacitor, a diode, and an inductor. The inductor and the diode are connected in series to form a series circuit. This series circuit is connected in parallel with the capacitor. The diode is connected to a magnetic coupling prevention circuit driving device. The parallel resonance circuit composed of the capacitor, the inductor, and the diode can be adjusted to the resonance frequency of the transmission coil 106 whose resonance frequency is adjusted to the same frequency as the magnetic resonance frequency when the diode is ON. Thereby, the magnetic coupling between the transmission coil 106 and the receiving coil unit 50 is prevented. When preventing magnetic coupling, a part of the energy irradiated from the transmission coil 106 becomes heat in the magnetic coupling prevention circuit. The coil element 52 is an example of the coil element of the present invention. The signal processing circuit 54 is an example of the heat source of the present invention.

[0053] The coil cover 56 is a cover that constitutes a container covering the plurality of coil elements 52 and the signal processing circuit 54 which is a plurality of heat sources. An electrical component including the plurality of coil elements 52 and the plurality of signal processing circuits 54 is accommodated inside the coil cover 56, and it is configured as a blanket-shaped receiving coil unit 50. Note that the plurality of coil elements 52 and the plurality of signal processing circuits 54 may be accommodated inside the coil cover 56 in a state of being fixed on a film (not shown). The film is a support member that fixes the positional relationship between the coil element 52 and the signal processing circuit 54 and suppresses displacement.

[0054] The coil cover 56 is formed in a bag shape by sewing or bonding the ends of a sheet-like material cut into one piece. In this example, the first sheet body 56A and the second sheet body 56B are sewn or bonded to form the bag-shaped coil cover 56. The material of the coil cover 56 may be a urethane-based resin such as polyurethane, a polyamide synthetic resin such as nylon, or the like. The surface exposed outside the first sheet body 56A constitutes an outer surface (hereinafter also referred to as a non-contact outer surface) that does not come into contact with the subject. The surface exposed outside the second sheet body 56B constitutes an outer surface (hereinafter also referred to as a contact outer surface) that comes into contact with the subject. A cable unit (not shown) is connected to the coil cover 56. This cable unit is a unit in which multi-channel cables for obtaining signals from each of the plurality of coil elements 52 are bundled and is electrically connected to the plurality of signal processing circuits 54.

[0055] FIG. 4 is a view of the receiving coil unit 50 as seen from the non-contact outer surface and the contact outer surface. 4-1 in FIG. 4 is a view as seen from the first sheet body 56A (non-contact outer surface). As shown in 4-1, the receiving coil unit 50 of this example has a substantially rectangular shape in which the side along the Z-axis direction is longer than the side along the X-axis direction. The shape of the receiving coil unit 50 is determined by the shape of the coil cover 56. The shape and size of the coil cover 56 are not particularly limited and can be appropriately changed according to the imaging site. The coil cover 56 may have, for example, a square shape when viewed from the first sheet body 56A. Also, the flexibility of the receiving coil unit 50 may be mainly determined by the characteristics of the coil cover 56. The 24 coil elements 52 housed in the coil cover 56 are regularly arranged two-dimensionally and are arranged over the entire surface of the coil cover 56. Specifically, six coil elements 52 are arranged side by side along the Z-axis direction. Also, four coil elements 52 are arranged side by side along the X-axis direction. Also, a plurality of heat sources (signal processing circuits 54) are regularly arranged two-dimensionally in the same manner as the plurality of coil elements 52. The arrangement of the plurality of heat sources (signal processing circuits 54) is not limited to an arrangement pattern that is regularly arranged two-dimensionally and may be an arrangement pattern that has no regularity.

[0056] 4-2 in FIG. 4 is a view as seen from the second sheet body 56B (contact outer surface). As shown in 4-2, the receiving coil unit 50 has a plurality of passage forming members 58 on the contact outer surface of the second sheet body 56B. The plurality of passage forming members 58 are regularly arranged two-dimensionally and are arranged in a grid pattern. In this example, twelve passage forming members 58 are arranged on the contact outer surface of the second sheet body 56B. The passage forming member 58 has a substantially rectangular shape in which the side along the Z-axis direction is longer than the side along the X-axis direction. The passage forming member 58 projects from the second sheet body 56B toward the subject 100.

[0057] The three passage forming members 58 are arranged in a row along the Z-axis direction so as to straddle two adjacent coil elements 52. Further, four passage forming members 58 are arranged in a row at positions corresponding to the coil elements 52 along the X-axis direction. The shape, quantity, and arrangement of the passage forming members 58 are not limited to the example shown in FIG. 4 as long as the passages described later are formed. In FIG. 4, the passage forming members 58 are shown in a color different from that of the coil cover 56 for easy understanding of the shape. Note that the coil cover 56 and the passage forming members 58 may have the same color or different colors. The passage forming member 58 is an example of the passage forming member of the present invention.

[0058] FIG. 5 is a diagram showing a state in which the receiving coil unit 50 is attached to the subject 100. FIG. 6 is a cross-sectional view of the receiving coil unit 50.

[0059] As shown in FIG. 5, the receiving coil unit 50 is constituted by a plurality of passage forming members 58, and four first-direction arrangement groups 60 and three second-direction arrangement groups 62 are formed. One first-direction arrangement group 60 is constituted by three passage forming members 58 arranged side by side in the Z-axis direction. The four first-direction arrangement groups 60 are arranged side by side in the X-axis direction. One second-direction arrangement group 62 is constituted by four passage forming members 58 arranged side by side in the X-axis direction. The three second-direction arrangement groups 62 are arranged side by side in the Z-axis direction. The arrangement directions of the passage forming members 58 in the first-direction arrangement group 60 and the second-direction arrangement group 62 are different.

[0060] The adjacent first-direction arrangement groups 60 form a first passage 64 extending in the first direction (Z-axis direction). In this example, three first passages 64 are formed. Also, the adjacent second-direction arrangement groups 62 form two second passages 66 extending in a second direction (X-axis direction) different from the first direction. The first passage 64 extends in the Z-axis direction across the entire outer contact surface of the receiving coil unit 50. The second passage 66 extends in the X-axis direction across the entire outer contact surface of the receiving coil unit 50. In this example, the passage extending along the longitudinal direction of the receiving coil unit 50 is described as the first passage 64, and the passage in a direction different from the first passage 64 is described as the second passage 66. However, the passage extending along the short-side direction of the receiving coil unit 50 may be regarded as the first passage 64, and the passage intersecting the first passage 64 may be regarded as the second passage 66.

[0061] The first passage 64 is an example of the first passage of the present invention. The second passage 66 is an example of the second passage of the present invention.

[0062] As shown in FIG. 6, the passage forming member 58 separates the receiving coil unit 50 (second sheet body 56B) from the subject 100. When the passage forming member 58 contacts the subject 100, the adjacent passage forming member 58, the second sheet body 56B, and the subject 100 form the first passage 64. The first passage 64 serves as a passage for air. Similarly, the adjacent passage forming member 58, the second sheet body 56B, and the subject 100 form the second passage 66. The second passage 66 serves as a passage for air. The first passage 64 and the second passage 66 promote the flow of air, and heat can be dissipated by this air flow. Note that the cross-sectional view of FIG. 6 is schematically shown in combination with the case of viewing from the Z-axis direction and the X-axis direction. The same may be described in the subsequent cross-sectional views.

[0063] In this example, the passage forming member 58 has a plate-like shape, and its thickness can be appropriately designed. When the coil element 52 is too far away from the subject 100 with the receiving coil unit 50 attached to the subject 100, the sensitivity of signal detection decreases. Therefore, it is preferable that the passage forming member 58 does not have a structure with an excessive thickness. From this perspective, the thickness of the passage forming member 58 is preferably 10 mm or less.

[0064] The passage forming member 58 can be composed of one material selected from the group consisting of non-magnetic metals, resins, closed-cell materials, and rubbers. As non-magnetic metals, copper, titanium, aluminum, brass, etc. can be applied to the passage forming member 58. As resins, polycarbonate, fluororesin, acrylic, etc. can be applied to the passage forming member 58. As closed-cell materials, bubble cushioning materials, expanded polystyrene, and foamed urethane, etc. can be applied to the passage forming member 58. The bubble cushioning material may be composed of a material containing polyethylene. As rubbers, urethane rubber, fluorinated rubber, etc. can be applied to the passage forming member 58. In addition, it is preferable that the passage forming member 58 has a load-bearing capacity such that the first passage 64 and the second passage 66 can be ensured even when the self-weight of the receiving coil unit 50 is applied.

[0065] FIG. 7 is a diagram for explaining the usage form of the receiving coil unit 50. 7-1 in FIG. 7 shows the case of using the fan 28 of the MRI apparatus 20, and 7-2 in FIG. 7 shows the case of heat convection using the heat from the subject 100.

[0066] As shown in 7-1 of FIG. 7, the fan 28 may be disposed near the imaging space 24 of the static magnetic field generating magnet 102. For example, the fan 28 is installed on the side opposite to the side where the table 32 is carried in. The fan 28 blows air Ar1 toward the opening on the carrying-in side in order to keep the thermal environment in the imaging space 24 constant. A part of the air Ar1 blown by the fan 28 passes through a first passage 64 (not shown) between the receiving coil unit 50 and the subject 100. Due to this air Ar1 flow, heat can be released from between the receiving coil unit 50 and the subject 100 to the side of the opening. Since the first passage 64 is formed throughout the entire region in the Z-axis direction, the air Ar1 can pass through the first passage 64 without being obstructed. Although the first passage 64 has been described, the second passage 66 can also allow the air Ar1 to pass through and release heat.

[0067] As shown in 7-2 of FIG. 7, the receiving coil unit 50 is used as a receiving coil for the abdomen. When heat H is generated from the subject 100, the heat H tries to escape from the receiving coil unit 50, and natural convection occurs. The first passage 64 formed in the receiving coil unit 50 promotes the escape of the heat H from the subject 100. As shown in 7-2, when the heat H escapes to the outside of the receiving coil unit 50, the first passage 64 becomes negative pressure with respect to the outside, so outside air Ar2 flows into the first passage 64 from the side opposite to the direction in which the heat H has escaped, and thus an air flow is generated in the first passage 64. The air flow can promote the escape of the heat H. Although the first passage 64 has been described, the heat H can escape from the second passage 66, and by allowing the outside air Ar2 to flow into the second passage 66, the heat H can be more effectively released.

[0068] FIG. 8 is a view showing a state in which the receiving coil unit 50 is attached to the subject 100 in a direction different from that in FIG. 5. FIG. 8 shows a state in which the receiving coil unit 50 in FIG. 5 is rotated approximately 90° clockwise (or counterclockwise) as viewed from the first sheet body 56A (non-contact outer surface). The receiving coil unit 50 has a first passage 64 and a second passage 66 formed therein. Therefore, even when the mounting orientation of the receiving coil unit 50 is changed, heat can be dissipated from the first passage 64 and the second passage 66.

[0069] 〔Structural Example of Passage Forming Member〕 In FIG. 6, a passage forming member 58 made of a single material (one type of material) and having a plate-like shape is illustrated. The material and structure of the passage forming member 58 are not limited to the passage forming member 58 shown in FIG. 6 as long as the first passage 64 and the second passage 66 can be formed. Other structures of the passage forming member 58 will be described below.

[0070] FIG. 9 shows a case where the passage forming members 80 and 84 are constituted by an assembly in which a plurality of members are assembled. The cross-sectional view of 9-1 in FIG. 9 shows that the passage forming member 80 is constituted by an assembly in which air bubble bags 81 (independent air bubble bags) are arranged along the coil cover 56. The passage forming member 80 has a plurality of dome-shaped air bubble bags 81 enclosing air bubbles 82, and the passage forming member 80 is constituted by an assembly in which the plurality of air bubble bags 81 are assembled. The passage forming member 80 forms the first passage 64 and the second passage 66 and also functions as a cushioning material since it is constituted by the air bubble bags 81. Since the passage forming member 80 is an assembly of the air bubble bags 81, it can have deformable characteristics. Therefore, when the receiving coil unit 50 is deformed according to the physique of the subject 100, the passage forming member 80 can also be deformed according to the physique of the subject 100. Each of the plurality of air bubble bags 81 of the passage forming member 80 is basically the same size and the same shape.

[0071] The cross-sectional view of 9-2 in Fig. 9 shows the case where the passage forming member 84 has a bellows structure. The passage forming member 84 has a plurality of rod-shaped members 85 with a solid structure, and the passage forming member 84 is composed of an assembly in which the rod-shaped members 85 are arranged along the coil cover 56 to form a bellows structure. The rod-shaped members 85 are made of resin (such as plastic). Since the passage forming member 84 has a bellows structure, it can be easily deformed between adjacent rod-shaped members 85. Therefore, the passage forming member 84 can form the first passage 64 and the second passage 66 and has deformable characteristics. Each of the plurality of rod-shaped members 85 is basically of the same size and the same shape.

[0072] The cross-sectional view of Fig. 10 shows the case where the passage forming member 86 is composed of an assembly in which a plurality of members are assembled and the sizes and shapes of the members constituting the assembly are different. The passage forming member 86 is composed of an assembly in which a first member 87 and a second member 88 having a different size from the first member 87 are arranged along the coil cover 56. The first member 87 contacts the subject 100, and the second member 88 does not contact the subject 100. The passage forming member 86 forms the first passage 64 and the second passage 66. Further, a groove 89 is formed in the passage forming member 86 due to the difference in thickness between the first member 87 and the second member 88. The groove 89 serves as a passage for air. With this configuration, heat can escape not only from the first passage 64 and the second passage 66 but also from the groove 89 in the region where the passage forming member 86 is arranged. The first member 87 and the second member 88 may be made of, for example, closed-cell polyurethane.

[0073] 11-1 in Fig. 11 is a cross-sectional view, and 11-2 in Fig. 11 is a view of the passage forming member 90 as seen from the side of the subject 100. This shows the case where the passage forming member 90 is composed of a single member and a plurality of grooves are formed on the surface of the passage forming member 90 facing the subject 100. The passage forming member 90 has a plate-like shape as a whole. On the surface of the passage forming member 90 facing the subject 100, four leg portions 90A are provided. Due to the four leg portions 90A, a first groove 90B and a second groove 90C intersecting the first groove 90B are formed in the passage forming member 90. The first groove 90B and the second groove 90C serve as air passages. The first groove 90B extends in a first direction across the entire surface of the passage forming member 90, and the second groove 90C extends in a second direction different from the first direction across the entire surface of the passage forming member 90. With this configuration, heat can escape not only from the first passage 64 and the second passage 66 but also from the first groove 90B and the second groove 90C in the region where the passage forming member 90 is disposed. The passage forming member 90 may be made of, for example, rubber. The groove 89, the first groove 90B, and the second groove 90C are examples of the grooves of the present invention.

[0074] The cross-sectional view of Fig. 12 shows the case where the passage forming member 92 has a hollow structure. The passage forming member 92 is provided with a tunnel-shaped through passage 92A penetrating through the passage forming member 92. The through passage 92A has openings at both ends and extends linearly along one direction. The through passage 92A serves as an air passage. With this configuration, heat can escape not only from the first passage 64 and the second passage 66 but also from the through passage 92A in the region where the passage forming member 92 is disposed. By aligning the directions of the through passages 92A, the flow of air in that direction is promoted, which is preferable. The passage forming member 92 may be made of, for example, resin or metal. Also, through holes may be formed in both side surfaces of the passage forming member 92 for the through passage 92A. With the through holes on both side surfaces, air passages can also be formed in the direction intersecting the through passage 92A.

[0075] The cross-sectional view of FIG. 13 shows a case where the passage forming member 94 has a multilayer structure in the thickness direction. The passage forming member 94 has a two-layer structure in which a first member 95 and a second member 96 are laminated in this order from the side of the second sheet body 56B. Both the first member 95 and the second member 96 have a plate-like shape. Also, in this example, the first member 95 and the second member 96 have substantially the same thickness and the same shape. On the other hand, the materials constituting the first member 95 and the second member 96 can be made different. The second member 96 that contacts the subject 100 can be made of a material with high cushioning properties (such as sponge or bead cushion), and the first member 95 can be made of a material with high load-bearing properties (such as resin or metal). That is, the passage forming member 94 can be composed of a combination of two or more materials. Since the first member 95 mainly defines the shapes of the first passage 64 and the second passage 66, and the second member 96 has cushioning properties, the second member 96 can alleviate the hitting (such as a rough feeling) that the subject 100 feels against the passage forming member 94. Although the case where the passage forming member 94 has a two-layer structure has been exemplified, the passage forming member 94 may have a multilayer structure of three or more layers. Also in the passage forming member 94, heat can be released from the first passage 64 and the second passage 66.

[0076] The cross-sectional view of FIG. 14 shows a case where a spacer 98 is disposed between the passage forming member 80 and the coil cover 56 of the receiving coil unit 50. The spacer 98 is provided on the second sheet body 56B (specimen contact surface) of the coil cover 56 and in the region where the passage forming member 80 is disposed. The spacer 98 is not a member having a uniform thickness, but is composed of members having different thicknesses and has an uneven shape. The passage forming member 80 is disposed so as to be in contact with the spacer 98. As shown in FIG. 14, since the passage forming member 80 has flexibility, the passage forming member 80 deforms following the shape of the spacer 98. Therefore, in the passage forming member 80, the surface opposite to the surface in contact with the spacer 98 (the surface facing the specimen 100) has an uneven shape. Due to the uneven shape, a space 83 where the passage forming member 80 does not contact is formed between the facing surface of the passage forming member 80 and the specimen 100. The space 83 serves as a passage for air. With this configuration, heat can escape not only from the first passage 64 and the second passage 66 but also from the space 83 in the region where the passage forming member 92 is disposed. The spacer 98 may be made of resin, rubber, metal, or the like. The spacer 98 is an example of the spacer of the present invention.

[0077] FIG. 15 is a plan view schematically showing another example of the arrangement form of the signal processing circuit 54 which is a heat source, and is a view of the receiving coil unit 50A seen from the first sheet body 56A (non-contact outer surface). A plurality of signal processing circuits 54 are arranged side by side in proximity in the Z-axis direction. When viewed in the Z-axis direction, if two signal processing circuits 54 are regarded as one set, three sets of signal processing circuits 54 are arranged. When viewed in the X-axis direction, if two signal processing circuits 54 are regarded as one set, four sets of signal processing circuits 54 are arranged.

[0078] Next, a preferable arrangement of the passage forming member 58 with respect to the receiving coil unit 50A shown in FIG. 15 will be described.

[0079] 16-1 of FIG. 16 is a view of the arrangement of the passage forming member 58A as seen from the second sheet body 56B (contact outer surface) of the receiving coil unit 50A. 16-2 of FIG. 16 is a view in the direction of arrow A shown in 16-1. As shown in 16-1 and 16-2 of FIG. 16, one passage forming member 58A is arranged at a position corresponding to one signal processing circuit 54. The passage forming member 58A and the signal processing circuit 54 correspond to each other one-to-one. A second passage 66 along the X-axis direction is formed between adjacent passage forming members 58A. Since the passage forming member 58A is arranged at a position corresponding to the signal processing circuit 54, it is possible to suppress the heat generated from the signal processing circuit 54 from being transmitted to the subject 100.

[0080] 17-1 of FIG. 17 is a view of the arrangement of the passage forming member 58B as seen from the second sheet body 56B (contact outer surface) of the receiving coil unit 50A. 17-2 of FIG. 17 is a view in the direction of arrow B shown in 17-1. As shown in 17-1 and 17-2 of FIG. 17, one passage forming member 58B is arranged at a position corresponding to two signal processing circuits 54. The passage forming member 58B and the signal processing circuit 54 correspond to each other one-to-two. Since the passage forming member 58B is arranged at a position corresponding to the signal processing circuit 54, it is possible to suppress the heat generated from the signal processing circuit 54 from being transmitted to the subject 100.

[0081] The receiving coil unit 50A in FIG. 17 can reduce the quantity of the passage forming member 58B compared to the receiving coil unit 50A in FIG. 16, which is advantageous in terms of cost.

[0082] The passage forming members 58A and 58B have a plate-like shape, but the structures of the other passage forming members described above can be applied. The passage forming members 58A and 58B may be made of a material with low thermal conductivity, for example, a resin such as a heat insulating material. As a resin suitable for the heat insulating material, for example, closed-cell polyurethane can be applied.

[0083] FIG. 18 is a diagram showing an arrangement of the passage forming members 58 different from a lattice shape in the receiving coil unit 50. It is a view of the receiving coil unit 50 as seen from the second sheet body 56B (contact outer surface). The second sheet body 56B has a first direction arrangement group 60A in which two passage forming members 58 are arranged in the Z-axis direction, a first direction arrangement group 60B in which one passage forming member 58 is arranged, and further has a second direction arrangement group 62A in which two passage forming members 58 are arranged in the X-axis direction. The passage forming members 58 are arranged in a zigzag pattern.

[0084] An adjacent first direction arrangement group 60A and first direction arrangement group 60B form a first passage 64, and an adjacent second direction arrangement group 62A forms a second passage 66. Also in the receiving coil unit 50 shown in FIG. 18, heat can be released from the first passage 64 and the second passage 66. In particular, heat can be released even when the orientation in which the receiving coil unit 50 is attached to the subject 100 is changed.

[0085] 〔Effects of the Embodiment〕 According to the receiving coil unit according to the above-described embodiment, the following effects can be obtained. That is, since the first passage and the second passage are formed by a plurality of passage forming members provided in the coil cover, heat can be released to the outside from between the subject and the receiving coil unit.

[0086] In addition to the first passage and the second passage, heat can be more effectively released to the outside by forming grooves in the arrangement region of the passage forming members. Also, heat can be more effectively released to the outside by providing a space in the passage forming members.

[0087] In the present embodiment, the signal processing circuit 54 including the anti-magnetic coupling circuit is shown as an example of the heat generating source of the receiving coil unit 50, but it is not limited thereto. For example, a single anti-magnetic coupling circuit inserted into the coil element or a preamplifier for amplifying the detected signal may be used. By arranging the passage forming member 58 at a position corresponding to the heat generating source, it is possible to suppress the generated heat from being transmitted to the subject 100.

[0088] In addition, in this embodiment, the coil cover 56 of the receiving coil unit 50 is in a detachable bag shape, but it is not limited to this. For example, it may be a shape formed by embedding with urethane or the like. The manufacturing cost can be reduced by reducing sewing work and the like.

[0089] Furthermore, it goes without saying that the present invention is not limited to the above-described embodiments, and various modifications are possible.

Explanation of Reference Numerals

[0090] 10 Medical imaging diagnosis system 50, 50A Receiving coil unit 52 Coil element 54 Signal processing circuit 56 Coil cover 58, 58A, 58B, 80, 84, 86, 90, 92, 94 Passage forming member 64 First passage 66 Second passage 82 Bubble 89 Groove 98 Spacer 100 Subject

Claims

1. A coil element for receiving a nuclear magnetic resonance signal of a subject, A flexible coil cover covering the periphery of the coil element, A plurality of passage forming members disposed on an outer surface of the coil cover that contacts the subject, the plurality of passage forming members forming a first passage extending in a first direction and a second passage extending in a second direction different from the first direction between the subject and the coil cover, A receiving coil unit comprising the above.

2. The receiving coil unit according to claim 1, wherein the passage forming member is composed of one material selected from the group consisting of non-magnetic metal, resin, closed-cell foam, and rubber or a combination of two or more materials.

3. The receiving coil unit according to claim 1 or 2, wherein the passage forming member has a plate-like shape.

4. The receiving coil unit according to claim 1 or 2, wherein the passage forming member is configured to be deformable.

5. The receiving coil unit according to claim 1 or 2, wherein the passage forming member is composed of two or more members having different shapes.

6. The receiving coil unit according to claim 1 or 2, wherein the passage forming member has a shape with a groove formed on the side of the subject.

7. The receiving coil unit according to claim 1 or 2, wherein the passage forming member has a hollow structure.

8. Comprising a heat source connected to the coil element, The receiving coil unit according to claim 1 or 2, wherein the passage forming member is disposed at a position corresponding to the heat source.

9. Comprising a heat source connected to each of the plurality of coil elements, The receiving coil unit according to claim 1 or 2, wherein the passage forming member is disposed at positions corresponding to the plurality of heat sources.

10. The receiving coil unit according to claim 1 or 2, wherein the passage forming member is composed of a heat insulating material.

11. The receiving coil unit according to claim 1 or 2, further comprising a spacer between the passage forming member and the outer surface of the coil cover.

12. The receiving coil unit according to claim 1 or 2, wherein the plurality of passage forming members are arranged in a grid pattern.

13. The receiving coil unit according to claim 1 or 2, wherein the coil cover is in a bag shape.

14. The receiving coil unit according to claim 1 or 2, A magnetic resonance imaging apparatus for processing a nuclear magnetic resonance signal received by the receiving coil unit, A medical image diagnosis system including the above.

15. A coil cover that covers the periphery of a coil element that receives a nuclear magnetic resonance signal of a subject, the coil cover comprising a plurality of passage forming members disposed on an outer surface of the coil cover that contacts the subject, the plurality of passage forming members forming a first passage extending in a first direction and a second passage extending in a second direction different from the first direction between the subject and the coil cover.

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