JP2018201868A - Gradient magnetic field coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate replacement of a temperature measuring element and prevent damage to the temperature measuring element. SOLUTION: A gradient magnetic field coil 103 includes a gradient magnetic field coil main body formed by impregnation, and a temperature measuring element 103d arranged on an outer surface of the gradient magnetic field coil main body and measuring the temperature of the gradient magnetic field coil main body. The current input / output end of the temperature measuring element 103d is connected to the coaxial cable. The temperature measuring element 103d is a thermistor. The coaxial cable is a semi-rigid cable. [Selection diagram] Fig. 1

Description

  Embodiments described herein relate generally to a gradient coil.

  In the magnetic resonance imaging apparatus, since the gradient magnetic field coil generates heat with the application of the pulse sequence, a temperature measuring element for measuring the temperature of the gradient magnetic field coil may be arranged. In this case, the temperature measuring element is often arranged at a position close to the gradient coil conductor outside the RF (Radio Frequency) shield provided to prevent coupling between the RF coil and the gradient coil.

  However, when the temperature measuring element is disposed outside the RF shield, the temperature measuring element itself is often embedded in the gradient magnetic field coil, so that maintenance at the time of failure is often not easy.

JP 2010-1205050 A Japanese Patent Laid-Open No. 2006-16077 JP-A-6-343616

  The problem to be solved by the present invention is to facilitate the replacement of the temperature measuring element and to prevent the temperature measuring element from being damaged.

  The gradient coil according to the embodiment includes a gradient coil body formed by impregnation, and a temperature measuring element that is disposed on the outer surface of the gradient coil body and measures the temperature of the gradient coil body. The current input / output terminal of the temperature measuring element is connected to a coaxial cable.

FIG. 1 is a diagram illustrating a magnetic resonance imaging apparatus according to an embodiment. FIG. 2 is a diagram illustrating an example of the configuration of the gradient magnetic field coil according to the embodiment. FIG. 3 is a diagram illustrating an example of the configuration of the gradient magnetic field coil according to the embodiment. FIG. 4 is a diagram for explaining the background related to the gradient coil according to the embodiment. FIG. 5 is a diagram for explaining the background related to the gradient coil according to the embodiment. FIG. 6 is a diagram illustrating an example of the arrangement of the temperature measuring elements according to the first embodiment. FIG. 7 is a diagram illustrating another example of the arrangement of the temperature measuring elements according to the first embodiment. FIG. 8 is a diagram illustrating an example of the arrangement of the temperature measuring elements according to the second embodiment. FIG. 9 is a diagram showing an example of the arrangement of the temperature measuring elements according to the third embodiment.

  Hereinafter, the gradient coil according to the embodiment will be described in detail with reference to the accompanying drawings.

(First embodiment)
FIG. 1 is a block diagram showing a magnetic resonance imaging apparatus 100 according to the embodiment. As shown in FIG. 1, a magnetic resonance imaging apparatus 100 includes a static magnetic field magnet 101, a static magnetic field power source (not shown) for driving the static magnetic field magnet 101, a gradient magnetic field coil 103, a gradient magnetic field power source 104, A bed 105, a bed control circuit 106, a transmission coil 107, a transmission circuit 108, a reception coil 109, a reception circuit 110, a sequence control circuit 120, and an image processing device 130 are provided. The magnetic resonance imaging apparatus 100 does not include the subject P (for example, a human body).

  Moreover, the structure shown in FIG. 1 is only an example. For example, the units in the sequence control circuit 120 and the image processing apparatus 130 may be configured to be integrated or separated as appropriate.

  The static magnetic field magnet 101 is a magnet formed in a hollow, substantially cylindrical shape, and generates a static magnetic field in an internal space. The static magnetic field magnet 101 is, for example, a superconducting magnet or the like, and is excited by receiving a current supplied from a static magnetic field power source. The static magnetic field magnet 101 may be a permanent magnet. In this case, the magnetic resonance imaging apparatus 100 may not include a static magnetic field power source. The static magnetic field power supply may be provided separately from the magnetic resonance imaging apparatus 100.

  The gradient magnetic field coil 103 is a coil formed in a hollow, substantially cylindrical shape, and is disposed inside the static magnetic field magnet 101. The temperature measuring element 103 d is a temperature measuring element that is disposed on the outer surface of the gradient magnetic field coil 103 and measures the temperature of the gradient magnetic field coil 103. The temperature measuring element 103d may be disposed on the outer surface of the gradient magnetic field coil body as a part of the gradient magnetic field coil 103, or as a component not included in the gradient magnetic field coil 103, It may be arranged on the outer surface. The temperature measuring element 103 d is connected to the sequence control circuit 120. For example, when the temperature measuring element 103 d senses an abnormality in the temperature of the gradient magnetic field coil 103, temperature information of the gradient magnetic field coil 103 is transmitted to the sequence control circuit 120. The sequence control circuit 120 performs, for example, processing such as stopping of the pulse sequence as needed based on the temperature information acquired from the temperature measuring element 103d. A more detailed description of the gradient magnetic field coil 103 and the temperature measuring element 103d will be described later with reference to FIGS.

  The couch 105 includes a couchtop 105a on which the subject P is placed. Under the control of the couch control circuit 106, the couchtop 105a is placed in the cavity (with the subject P placed) on the cavity ( Insert it into the imaging port. Usually, the bed 105 is installed so that the longitudinal direction is parallel to the central axis of the static magnetic field magnet 101. The couch control circuit 106 drives the couch 105 under the control of the image processing device 130 to move the couchtop 105a in the longitudinal direction and the vertical direction.

  The transmission coil 107 is disposed inside the gradient magnetic field coil 103 and receives a supply of an RF (Radio Frequency) pulse from the transmission circuit 108 to generate a high-frequency magnetic field. The transmission circuit 108 supplies an RF pulse corresponding to a Larmor frequency determined by the type of the target atom and the magnetic field strength to the transmission coil 107.

  The reception coil 109 is disposed inside the gradient magnetic field coil 103 and receives a magnetic resonance signal emitted from the subject P due to the influence of the high-frequency magnetic field. When receiving the magnetic resonance signal, the reception coil 109 outputs the received magnetic resonance signal to the reception circuit 110.

  Note that the transmission coil 107 and the reception coil 109 described above are merely examples. What is necessary is just to comprise by combining one or more among the coil provided only with the transmission function, the coil provided only with the reception function, or the coil provided with the transmission / reception function.

  The receiving circuit 110 detects the magnetic resonance signal output from the receiving coil 109, and generates magnetic resonance data based on the detected magnetic resonance signal. Specifically, the receiving circuit 110 generates magnetic resonance data by digitally converting the magnetic resonance signal output from the receiving coil 109. In addition, the reception circuit 110 transmits the generated magnetic resonance data to the sequence control circuit 120. The receiving circuit 110 may be provided on the gantry device side including the static magnetic field magnet 101, the gradient magnetic field coil 103, and the like.

  The sequence control circuit 120 performs imaging of the subject P by driving the gradient magnetic field power source 104, the transmission circuit 108, and the reception circuit 110 based on the sequence information transmitted from the image processing apparatus 130. That is, the sequence control circuit 120 executes a pulse sequence by applying a voltage to the gradient coil 103 based on the sequence information. Here, the sequence information is information defining a procedure for performing imaging. The sequence information includes the strength of the current supplied from the gradient magnetic field power source 104 to the gradient magnetic field coil 103, the timing of supplying the current, the strength of the RF pulse supplied from the transmission circuit 108 to the transmission coil 107, the timing of applying the RF pulse, The timing at which the circuit 110 detects the magnetic resonance signal is defined. For example, the sequence control circuit 120 is an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Gate Array), or an electronic circuit such as a CPU (Central Processing Unit) or MPU (Micro Processing Unit).

  When the magnetic resonance data is received from the reception circuit 110 as a result of driving the gradient magnetic field power source 104, the transmission circuit 108, and the reception circuit 110 and imaging the subject P, the sequence control circuit 120 displays the received magnetic resonance data as an image. Transfer to the processing device 130. In addition, based on the signal output from the temperature measuring element 103d, the control of the gradient magnetic field power supply is stopped as an abnormal process, or the gradient magnetic field power supply is turned off in some cases. The sequence control circuit 120 is an example of a sequence control unit.

  The image processing apparatus 130 performs overall control of the magnetic resonance imaging apparatus 100, image generation, and the like. The image processing device 130 includes a storage circuit 132, an input device 134, a display 135, and a processing circuit 150. The processing circuit 150 includes an interface function 131, a control function 133, and an image generation function 136.

  In the first embodiment, the processing functions performed by the interface function 131, the control function 133, and the image generation function 136 are stored in the storage circuit 132 in the form of a program that can be executed by a computer. The processing circuit 150 is a processor that realizes a function corresponding to each program by reading the program from the storage circuit 132 and executing the program. In other words, the processing circuit 150 in a state where each program is read has each function shown in the processing circuit 150 of FIG. In FIG. 1, it has been described that the processing functions performed by the interface function 131, the control function 133, and the image generation function 136 are realized by a single processing circuit 150, but a plurality of independent processors are combined. The processing circuit 150 may be configured so that the functions are realized by each processor executing a program.

  In other words, each function described above may be configured as a program, and one processing circuit may execute each program, or a specific function may be implemented in a dedicated independent program execution circuit. May be.

  The term “processor” used in the above description is, for example, a CPU (Central Processing Unit), a GPU (Graphical Processing Unit), an application specific integrated circuit (ASIC), a programmable logic device (for example, It means circuits such as a programmable logic device (SPLD), a complex programmable logic device (Complex Programmable Logic Device), and a field programmable gate array (FPGA). . The processor implements a function by reading and executing the program stored in the storage circuit 132.

  Instead of storing the program in the storage circuit 132, the program may be directly incorporated in the processor circuit. In this case, the processor realizes the function by reading and executing the program incorporated in the circuit. Similarly, the bed control circuit 106, the transmission circuit 108, the reception circuit 110, and the like are also configured by electronic circuits such as the processor described above.

  The processing circuit 150 transmits sequence information to the sequence control circuit 120 by the interface function 131 and receives magnetic resonance data from the sequence control circuit 120. When the processing circuit 150 having the interface function 131 receives the magnetic resonance data, the processing circuit 150 stores the received magnetic resonance data in the storage circuit 132. The magnetic resonance data stored in the storage circuit 132 is arranged in the k space by the control function 133. As a result, the storage circuit 132 stores k-space data.

  The storage circuit 132 includes magnetic resonance data received by the processing circuit 150 having the interface function 131, k-space data arranged in the k space by the processing circuit 150 having the control function 133, and a processing circuit 150 having the image generation function 136. The image data generated by the above is stored. For example, the storage circuit 132 is a RAM (Random Access Memory), a semiconductor memory device such as a flash memory, a hard disk, an optical disk, or the like.

  The input device 134 receives various instructions and information input from the operator. The input device 134 is, for example, a pointing device such as a mouse or a trackball, a selection device such as a mode switch, or an input device such as a keyboard. The display 135 displays a GUI (Graphical User Interface) for receiving input of imaging conditions, an image generated by the processing circuit 150 having the image generation function 136, and the like under the control of the processing circuit 150 having the control function 133. To do. The display 135 is a display device such as a liquid crystal display.

  The processing circuit 150 performs overall control of the magnetic resonance imaging apparatus 100 by the control function 133, and controls imaging, image generation, image display, and the like. For example, the processing circuit 150 having the control function 133 accepts input of imaging conditions (imaging parameters, etc.) on the GUI, and generates sequence information according to the accepted imaging conditions. In addition, the processing circuit 150 having the control function 133 transmits the generated sequence information to the sequence control circuit 120.

  The processing circuit 150 uses the image generation function 136 to read k-space data from the storage circuit 132, and performs reconstruction processing such as Fourier transform on the read k-space data to generate an image.

  Subsequently, the gradient magnetic field coil 103 according to the embodiment will be described in more detail with reference to FIGS. 2 and 3. 2 and 3 are diagrams illustrating examples of the configuration of the gradient coil 103 according to the embodiment. 2 is an enlarged cross-sectional view of the static magnetic field magnet 101, the gradient magnetic field coil 103, the transmission coil 107, and the reception coil 109 in FIG.

  2, a static magnetic field magnet 101, a transmission coil 107, and a reception coil 109 correspond to the static magnetic field magnet 101, the transmission coil 107, and the reception coil 109 in FIG. 1 is disposed on the outer surface of the gradient coil body 103b and the gradient coil body 103b, for example, as shown in FIG. 2, and the temperature of the gradient coil body 103b is determined. A temperature measuring element 103d for measuring The gradient magnetic field coil main body 103b is formed to include a coil portion 103a that is a coil portion of the gradient magnetic field coil main body 103b and an RF (Radio Frequency) shield 103c, for example, by impregnation with resin or the like, and is substantially cylindrical. Has a shape.

  FIG. 3 is a sectional view showing the gradient magnetic field coil 103 and the like in the section A-A ′ of FIG. 2. As shown in FIG. 3, the gradient magnetic field coil 103 has a substantially circular cross section, and the temperature of the gradient magnetic field coil body 103b and the temperature disposed on the outer surface of the inner peripheral portion of the gradient magnetic field coil body 103b. The transmitter coil 107 and the receiver coil 109 are disposed inside the measurement element 103d so as to surround the subject P. The gradient coil 103 has a coil portion 103a and an RF shield 103c, and has a structure formed by impregnation.

  Returning to FIG. 2, the coil portion 103 a of the gradient magnetic field coil main body 103 b is a coil corresponding to each axis of the gradient magnetic field coil 103 (coil corresponding to the X axis, coil corresponding to the Y axis, coil corresponding to the Z axis, etc.). Is configured to include a main coil laminated. The coil portion 103a is formed to be impregnated with, for example, a resin. A specific example of the coil portion 103a is an ASGC (Actively Shielded Gradient Coil) configured to include a main coil that generates a gradient magnetic field and a shield coil that generates a magnetic field for shielding that cancels the leakage magnetic field. In such a case, the gradient magnetic field coil is configured, for example, by arranging a cooling pipe, a main coil, a cooling pipe, a shim tray, a cooling pipe, and a shield coil in order of increasing distance from the space inside the cylinder.

  The main coil is formed by combining three coils corresponding to the X, Y, and Z axes orthogonal to each other, and these three coils are individually supplied with current from the gradient magnetic field power supply 104. , X, Y, and Z to generate a gradient magnetic field whose magnetic field strength varies along each axis. The gradient magnetic fields of the X, Y, and Z axes generated by the coil portion 103a are, for example, a slice gradient magnetic field Gs, a phase encoding gradient magnetic field Ge, and a readout gradient magnetic field Gr. Similarly, the shield coil is formed by combining three coils corresponding to the X, Y, and Z axes orthogonal to each other, and these three coils are individually supplied with current from the gradient magnetic field power source 104. When supplied, a magnetic field for shielding is generated along each of the X, Y, and Z axes. The cooling pipe cools the coil by circulating the refrigerant. The shim tray realizes shimming by storing a predetermined number of iron shims in a predetermined pocket.

  In addition, as an example of the coil part 103a, it is not restricted to ASGC, For example, the normal coil which does not have a shield coil may be sufficient. In such a case, the coil portion 103 a is formed by combining three coils corresponding to the X, Y, and Z axes orthogonal to each other, and these three coils individually supply current from the gradient magnetic field power supply 104. In response, a gradient magnetic field is generated in which the magnetic field strength varies along the X, Y, and Z axes. The gradient magnetic field power source 104 supplies a current to the coil portion 103a.

  The RF shield 103c is a high-frequency radio wave shield (RF shield) for preventing electromagnetic coupling between the gradient coil main body 103b, particularly the coil portion 103a, and the RF coils such as the transmission coil 107 and the reception coil 109. The RF shield 103c is made of, for example, a copper plate. The material of the RF shield 103c is not limited to a copper plate, and may be a metal made of other materials, for example. The RF shield 103c is impregnated with a resin or the like and embedded in the gradient magnetic field coil body 103b.

  The temperature measuring element 103d is a temperature measuring element for measuring the temperature of the gradient magnetic field coil body 103b. An example of the temperature measuring element 103d is a semiconductor element such as a thermistor. Further, as another example of the temperature measuring element 103d, an element using a resistance temperature detector such as a linear resistance or a platinum resistance temperature detector, an element using a thermocouple, or an IC temperature sensor may be used.

  The temperature measuring element 103d according to the embodiment is disposed on the outer surface of the inner peripheral portion of the gradient coil body 103b. Therefore, the temperature measurement element 103d according to the embodiment is disposed between the RF coil (the transmission coil 107 and the reception coil 109) installed on the inner periphery of the gradient coil main body 103b and the RF shield 103c.

  Here, the background of disposing the temperature measuring element 103d on the outer surface of the gradient magnetic field coil body 103b in the embodiment will be described. FIG.4 and FIG.5 is a figure for demonstrating the background which concerns on the gradient magnetic field coil which concerns on embodiment. 4 and 5 show a case where the temperature measuring element 103d is arranged outside the RF shield 103c.

  In the case of FIGS. 4 and 5, since the temperature measuring element 103d is disposed outside the RF shield 103c, the coupling between the RF coil and the gradient coil body 103b is suppressed. However, in such an arrangement of the temperature measuring element 103d, since the temperature measuring element 103d is embedded in the gradient magnetic field coil body 103b, maintenance and replacement at the time of failure or damage are not easy. Therefore, from the viewpoint of ease of maintenance at the time of failure, it is desirable that the temperature measuring element 103d is disposed on the outer peripheral surface of the gradient coil body 103b. Further, even when the hot spot is in the innermost layer of the gradient magnetic field coil or when the location of the temperature measurement element 103d is limited and outside the RF shield 103c, the temperature measurement element 103d is located outside the gradient coil main body 103b. It is desirable to be placed on the surface.

  In view of such a background, in the embodiment, the temperature measuring element 103d is disposed on the outer surface of the gradient coil body 103b. As a result, the temperature measuring element 103d is disposed inside the RF shield 103c, so that the current supply line of the temperature measuring element 103d and the sensor of the temperature measuring element 103d itself are not connected to the transmitting coil 107 and the receiving coil. It may be affected by the coil 109. Therefore, in the embodiment, the influence of the temperature measurement element 103d from the transmission coil 107 and the reception coil 109 is reduced by devising the arrangement and wiring of the temperature measurement element 103d. Thereby, replacement of the temperature measuring element 103d can be facilitated and damage to the temperature measuring element 103d can be prevented.

  More specifically, in the first embodiment, the temperature measuring element 103d is connected to a coaxial cable in order to solve the above-described point. When a thermistor or the like is selected as the temperature measuring element 103d, for example, the current flowing through the current input / output terminal is a direct current. In the embodiment, the reason for using a coaxial cable which is not usually used for transmission of a direct current and mainly used for transmission of a high frequency signal is as follows. Is mentioned.

  6 and 7 are diagrams illustrating an example of the arrangement of the temperature measuring elements according to the first embodiment. 6 and 7 are enlarged views of the vicinity of the temperature measuring element 103d and the RF shield 103c in FIG. In FIGS. 6 and 7, the upper and lower sides are inverted as compared with FIG. 2. As shown in FIG. 6, the temperature measuring element 103 d is connected to the coaxial cable 12. Specifically, the current supply line (conductor 11a) of the temperature measuring element 103d is connected to the core wire of the coaxial cable 12, and the other conductor 11b of the temperature measuring element 103d is connected to the shield wire of the coaxial cable 12. Here, if the potential of the shielded wire of the coaxial cable 12 is different from the potential of the RF shield 103c, undesirable effects such as the generation of stray capacitance occur. Therefore, the temperature measuring element 103d is electrically grounded to the RF shield 103c. The

  FIG. 6 shows the grounding between the temperature measuring element 103d and the RF shield 103c when the coaxial cable 12 is a semi-rigid cable that is a cable having a conductor formed on the outside. Since the coaxial cable 12 is a semi-rigid cable and the outside is formed of a conductor, the RF shield 103c embedded in the gradient coil body 103b and the temperature measuring element 103d are electrically grounded through the contact point 20. Is done. Thereby, external electromagnetic and electrostatic noise does not enter inside the shielded wire of the coaxial cable 12 due to electrostatic shielding. Further, in the coaxial cable 12, there is no interlinkage magnetic flux with the outside. Therefore, although the temperature measuring element 103d is disposed on the outer surface of the gradient coil body 103b, it is possible to shield a high-frequency electromagnetic field caused by the RF coil.

  FIG. 7 shows another example of the arrangement of the temperature measuring elements 103d according to the first embodiment. In the example of FIG. 7, the coaxial cable 12 is arranged outside the gradient magnetic field coil body 103b. In such a case, the temperature measuring element 103d and the RF shield 103c are electrically grounded through the conductor 21 embedded in the gradient coil body 103b. Thereby, although the temperature measuring element 103d is disposed on the outer surface of the gradient magnetic field coil main body 103b, it is possible to shield a high-frequency electromagnetic field caused by the RF coil.

  As described above, in the first embodiment, the temperature measuring element 103d is disposed on the outer surface of the gradient coil body 103b, and the current input end of the temperature measuring element 103d is connected to the coaxial cable 12. Thereby, replacement of the temperature measuring element 103d can be facilitated and shielding from the RF signal can be performed, and damage to the temperature measuring element 103d can be prevented.

(Second Embodiment)
In the second embodiment, a case will be described in which the temperature measurement element 103d is prevented from being damaged by connecting a circuit in which a cross diode and a capacitor are connected in series to the current input / output terminal of the temperature measurement element 103d. FIG. 8 is a diagram illustrating an example of the arrangement of the temperature measuring elements 103d according to the second embodiment. As shown in FIG. 8, a circuit in which a cross diode 30 and a capacitor 31 are connected in series is connected to the conductive wire 11a and the conductive wire 11b which are current input / output terminals of the temperature measuring element 103d.

  Here, the cross diode 30 is a circuit configured by connecting a diode 30a and a diode 30b having different polarities in parallel. Next, the operation of the cross diode 30 will be described. In each of the diode 30a and the diode 30b, a current flows (functions as a conductor) when a voltage applied to both ends is in a forward direction and exceeds a predetermined threshold value, and a current does not flow in other cases (insulator) Behave as a device). That is, when the voltage difference between the conductor 11a and the conductor 11b exceeds a predetermined threshold, the cross diode 30 functions as a bypass circuit due to a current flowing through the cross diode 30, and the voltage difference between the conductor 11a and the conductor 11b is a predetermined threshold. If it does not exceed, it behaves as an element that does not particularly operate.

  Further, the capacitor 31 plays a role of passing an alternating current component of the current and blocking the passage of the direct current component.

  Therefore, the above-described circuit in which the cross diode 30 and the capacitor 31 are connected in series prevents a direct current component from passing, and when a high-frequency voltage equal to or higher than a predetermined threshold is applied between the conductors 11a and 11b, It functions as a circuit that releases current through the circuit. Therefore, when an unexpectedly high frequency voltage is applied between the conducting wire 11a and the conducting wire 11b of the temperature measuring element 103d due to the influence of the RF coil, the circuit breaks the temperature measuring element 103d by passing a current through the circuit. To prevent.

  In addition, one end of the conducting wire 11a and the conducting wire 11b may be connected to the twist cable 50 in order to further suppress the influence from the RF coil.

  In this manner, in the second embodiment, a circuit that bypasses a high-frequency and high-voltage component is added to the temperature measurement element 103d, so that the temperature measurement element 103d can be prevented from being damaged.

(Third embodiment)
In the third embodiment, a case where the temperature measuring element 103d is electromagnetically shielded by a shield material will be described. FIG. 9 is a diagram illustrating an example of the arrangement of the temperature measurement elements 103d according to the third embodiment. As shown in FIG. 9, the temperature measuring element 103 d is electromagnetically shielded by the shield material 40. As the material of the shield material 40, for example, a metal such as copper is used. Similarly, it is desirable that the shield material 40 is electrically grounded to the RF shield 103c. The grounding of the shield material 40 and the RF shield 103c is performed through the conductor 21 embedded in the gradient coil body 103b, as in the case of FIG. In this manner, in the third embodiment, the temperature measuring element 103d is shielded by the shield material 40, so that the temperature measuring element 103d can be prevented from being damaged.

  Thus, according to the gradient magnetic field coil 103 and the magnetic resonance imaging apparatus 100 according to one embodiment, the temperature measuring element 103d can be easily replaced and the temperature measuring element 103d can be prevented from being damaged.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

103 Gradient magnetic field coil 103b Gradient magnetic field coil body 103c RF shield 103d Temperature measuring element

Claims (6)

A gradient coil body formed by impregnation;
In the gradient coil, which is disposed on the outer surface of the gradient coil body and includes a temperature measuring element for measuring the temperature of the gradient coil body,
A gradient coil is connected to a coaxial cable at the current input / output end of the temperature measuring element.   The gradient coil according to claim 1, wherein the temperature measuring element is a thermistor.   The gradient magnetic field coil according to claim 1, wherein the coaxial cable is a semi-rigid cable. A gradient coil body formed by impregnation;
In the gradient coil, which is disposed on the outer surface of the gradient coil body and includes a temperature measuring element for measuring the temperature of the gradient coil body,
A gradient magnetic field coil, wherein a current input / output terminal of the temperature measuring element is connected to a circuit in which a cross diode and a capacitor are connected in series. A gradient coil body formed by impregnation;
In the gradient coil, which is disposed on the outer surface of the gradient coil body and includes a temperature measuring element for measuring the temperature of the gradient coil body,
The temperature measuring element is a gradient coil that is electromagnetically shielded by a shielding material.   The gradient magnetic field coil according to claim 5, wherein the shield material is electrically grounded with an RF shield.

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