JP2005124855A - Magnetic resonance imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low cost technique shortening an operating time by improving the operability and allowing positioning of a subject without giving discomfort feeling in an operation of setting the subject in the center of a static magnetic field in MRI apparatus. <P>SOLUTION: A light emitting element is mounted on the upper face of a receiving coil, a light receiving element is mounted on the opening part of a gantry, and when a top plate mounted with the subject and the receiving coil is inserted in the center of the static magnetic field, the light receiving element detects an optical signal from the light emitting element to find the position of the top plate, then the top plate is moved by a predetermined distance which is determined by the shape of the gantry and the subject and the receiving coil are inserted in the center of the static magnetic field. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a magnetic resonance imaging (hereinafter abbreviated as MRI) apparatus for displaying an image of a desired cross-section of a subject using a nuclear magnetic resonance phenomenon (hereinafter abbreviated as NMR), and in particular, an imaging region of the subject. The present invention relates to a technique for easily moving to an imaging space of an MRI apparatus.

  In order to set the imaging region of the subject in the imaging space in the MRI apparatus, a projector for positioning is generally provided at the opening of the gantry or outside. The procedure for setting the imaging region of the subject in the imaging space of the MRI apparatus using this projector is as follows. In other words, the subject and the receiving coil are first placed on the top of the bed at the opening or outside of the gantry, and then the subject and the receiver are positioned so that the imaging center of the subject comes to the center of the irradiation light from the projector. The arrangement of the coils is determined, and finally, the top board is electrically or manually moved so that the imaging center of the subject comes to the center of the imaging space of the apparatus. Since the distance between the center of the irradiation light of the projector and the center of the imaging space is a fixed distance, the distance between the imaging center of the subject and the center of the imaging space of the device is also automatically determined, and the top plate is moved by that distance. By moving, it is possible to reliably set a desired part of the subject in the imaging space.

  When the gantry shape is a horizontal magnetic field type tunnel type, the top plate moves only in the front-rear direction (static magnetic field direction). However, in the vertical magnetic field type open type, the top plate moves only in the front-rear side direction (static magnetic field and It is also possible to image a part away from the body axis center of the subject such as a shoulder.

  However, in the setting procedure as described above, since the operator aligns the imaging center of the subject with the irradiation center of the projector, the top plate on which the subject is placed must be moved back and forth and left and right electrically or manually. The setting takes time, and the subject is uncomfortable at the time of fine adjustment, and the operator is forced to perform troublesome operations.

Therefore, a technique has been proposed that can easily move the imaging center of the subject to the center of the imaging space without performing such troublesome operations. For example, in [Patent Document 1], a mark is attached on a subject, the mark is detected by the image processing unit, and the spatial position of the mark is detected, and the bed control unit detects the spatial position and the inspection position of the mark (imaging position). The movement distance of the top plate is detected from the center of the space), and the bed is moved along this movement distance.
Japanese Unexamined Patent Publication No. 08-257024

  It may be difficult to apply the method of attaching a mark on a subject as in the above [Patent Document 1] to an MRI apparatus. The reason is as follows. That is, in order to detect the NMR signal from the subject, a receiving coil is generally arranged close to the subject, and it is difficult to recognize the mark position from the outside because the receiving coil is in the way. Because it becomes. Further, in the case of abdominal imaging, the position of the mark varies depending on the respiratory movement of the subject, so that it is difficult to recognize the accurate spatial position of the mark. In addition, it is difficult to recognize the mark after the subject is inserted into the gantry. [Patent Document 1] does not consider these problems.

  Therefore, the present invention has been made to solve the above-described problem, and facilitates the operation when setting the imaging center of the subject to the center of the imaging space, thereby improving the operability, and as a result, the operation time. An object of the present invention is to provide an MRI apparatus that can shorten the length of the object and does not cause discomfort to the subject.

In order to solve the above problems, the present invention is configured as follows.
According to the first embodiment of the present invention, there is provided a gantry including a static magnetic field generation source for forming a static magnetic field space, and a top board for placing and inserting a subject in the static magnetic field space. A bed comprising: a biological signal receiving means for receiving a nuclear magnetic resonance signal from the subject placed on the top board; and a top board control means for controlling the movement of the top board. In the provided MRI apparatus,
One of the gantry and the biological signal receiving means is provided with position information transmitting means, and the other is provided with position information receiving means.
The location information receiving means detects a signal from the location information sending means,
The top panel control unit controls signal transmission from the position information transmission unit, and based on a detection signal from the position information reception unit, the position of the biological signal reception unit at the time of signal detection and the static magnetic field space A distance to the center of the static magnetic field space is obtained, and the top plate is moved by a distance to the center of the static magnetic field space so that the biological signal receiving means is in the center of the static magnetic field space.

  Thereby, the position information transmitting means and the position information receiving means for detecting the position information of the biological signal receiving means can be attached to the gantry and the biological signal receiving means, and the position of the biological signal receiving means can be automatically detected. This eliminates the need for troublesome positioning operations. Therefore, the operation of setting the imaging center of the subject as the center of the imaging space is facilitated, the operation time can be shortened, and the imaging center of the subject can be set as the center of the imaging space without causing discomfort to the subject. become.

Further, according to the second embodiment of the present invention, in the MRI apparatus according to the first embodiment,
The top board control means obtains the position of the biological signal receiving means at the time of signal detection and the distance to a predetermined position on the bed based on the detection signal from the position information receiving means, and the top board is the bed. The top plate is moved by a distance to a predetermined position on the bed so as to come to a predetermined position above.
As a result, the subject and the biological signal receiving means can be automatically taken out to a predetermined position on the bed, so that the operation can be facilitated and the operation time can be shortened, and the subject is not uncomfortable. I can do it.

Further, according to the third embodiment of the present invention, in the MRI apparatus according to the first or second embodiment,
The position information transmitting means transmits an optical signal, and the position information receiving means receives an optical signal.
As a result, the position of the biological signal receiving means can be recognized using light as a medium, and the imaging center of the subject can be set to the center of the imaging space or taken out to a predetermined position on the bed with an inexpensive configuration. Become.

Further, according to the fourth embodiment of the present invention, in the MRI apparatus according to the first or second embodiment,
The position information transmitting means transmits a sound signal, and the position information receiving means receives a sound signal.
As a result, the position of the biological signal receiving means can be recognized using sound as a medium, and the imaging center of the subject can be set as the center of the imaging space or taken out to a predetermined position on the bed with an inexpensive configuration. Become.

Further, according to the fifth embodiment of the present invention, in the MRI apparatus according to the first to fourth embodiments,
The position information receiving means provided in the gantry is configured by arranging a plurality of position information receiving elements in a direction perpendicular to the longitudinal direction of the top plate,
The top plate control means obtains the position of the biological signal receiving means with respect to a direction perpendicular to the longitudinal direction of the top plate corresponding to the position information receiving element that has detected the signal.
As a result, the position in the direction perpendicular to the longitudinal direction of the top plate of the biological signal receiving means can be easily recognized.

According to the sixth embodiment of the present invention, in the MRI apparatus according to the first to fifth embodiments,
The position information transmitting or receiving means provided in the biological signal receiving means is disposed on the upper surface on the sensitivity center of the biological signal receiving means.
As a result, there is no configuration that obstructs the transmission and reception of signals between the biological signal receiving means and the gantry, so that the position of the biological signal receiving means can be easily detected.

Further, according to the seventh embodiment of the present invention, in the MRI apparatus according to the first to sixth embodiments,
The position information transmitting or receiving means provided in the gantry is disposed on a surface facing the top plate above the gantry opening.
As a result, the position information transmitting or receiving means provided in the gantry directly faces the biological signal receiving means, so that the position of the biological signal receiving means can be easily detected.

  Since the present invention is configured as described above, it is possible to improve the operability for setting the imaging region of the subject at the imaging center of the MRI apparatus with an inexpensive configuration. As a result, the operation time can be shortened, and the subject can be set in the imaging space without causing discomfort to the subject.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment of the invention, and the repetitive description thereof is omitted.

  FIG. 1 shows an overall perspective view of an embodiment of a vertical magnetic field type (open type) MRI apparatus. This MRI apparatus uses a NMR phenomenon to obtain a tomographic image of a subject, and as shown in FIG. 1, a gantry 51 that houses various devices for inducing a NMR phenomenon in a subject and receiving NMR signals. A bed 52 having a top plate 56 on which the subject is placed, a power source for driving various devices in the gantry and a housing 53 for controlling various control devices, and a tomography of the subject by processing received NMR signals It consists of a processing device 54 for reconstructing an image, and each is connected by a power source / signal line 55. The gantry and the table are arranged in a shield room that shields a high-frequency electromagnetic wave and a static magnetic field (not shown), and the casing and the processing apparatus are arranged outside the shield room.

  FIG. 2 shows a block configuration diagram in which the configuration of the MRI apparatus of FIG. 1 is disassembled for each more detailed function. As shown in FIG. 2, the MRI apparatus includes a static magnetic field generation system 2, a gradient magnetic field generation system 3, a transmission system 5, a reception system 6, a signal processing system 7, a sequencer 4, and a central processing unit (CPU). 8 and configured.

  The static magnetic field generation system 2 generates a uniform static magnetic field in the space around the subject 1 in the direction of the body axis (horizontal magnetic field method) or in the direction orthogonal to the body axis (vertical magnetic field method). Around this is a normal or superconducting static magnetic field generation source. The static magnetic field generation system 2 is accommodated in the gantry 51.

  The gradient magnetic field generation system 3 includes a GC 9 wound in three axial directions of X, Y, and Z, and a gradient magnetic field power source 10 that drives each GC 9, and each coil according to a command from a sequencer 4 described later. By driving the gradient magnetic field power supply 10, gradient magnetic fields Gx, Gy, and Gz in the three-axis directions of X, Y, and Z are applied to the subject 1. More specifically, a slice direction gradient magnetic field pulse (Gs) is applied in one of X, Y, and Z to set the slice plane for the subject 1, and the phase encode direction gradient magnetic field is applied to the remaining two directions. A pulse (Gp) and a frequency encoding direction gradient magnetic field pulse (Gf) are applied, and position information in each direction is encoded in the echo signal. The GC 9 is housed in the gantry 51 and the gradient magnetic field power supply 10 is housed in the housing 53, respectively.

  The sequencer 4 is a control means that repeatedly applies a high-frequency magnetic field pulse (hereinafter referred to as “RF pulse”) and a gradient magnetic field pulse in a predetermined pulse sequence, and operates under the control of the CPU 8 to collect tomographic image data of the subject 1. Various commands necessary for the transmission are sent to the transmission system 5, the gradient magnetic field generation system 3, and the reception system 6. Furthermore, in the MRI apparatus of the present invention, the sequencer 4 includes means capable of measuring while changing the output of the RF pulse. The sequencer 4 is accommodated in the housing 53.

  The transmission system 5 irradiates an RF pulse to cause nuclear magnetic resonance to the nuclear spins of atoms constituting the biological tissue of the subject 1, and includes a high frequency oscillator 11, a modulator 12, a high frequency amplifier 13, and a transmission side And a high-frequency coil 14a. The high-frequency pulse output from the high-frequency oscillator 11 is amplitude-modulated by the modulator 12 at a timing according to a command from the sequencer 4, and the amplitude-modulated high-frequency pulse is amplified by the high-frequency amplifier 13 and then placed close to the subject 1. By supplying to the high frequency coil 14a, the subject 1 is irradiated with the RF pulse. In general, the high-frequency coil 14 a is accommodated in the gantry 51, and the others are accommodated in the housing 53.

The receiving system 6 detects an echo signal (NMR signal) emitted by nuclear magnetic resonance of nuclear spins constituting the biological tissue of the subject 1, and receives a high-frequency coil 14b on the receiving side, a signal amplifier 15, and quadrature detection. And an A / D converter 17. The NMR signal of the response of the subject 1 induced by the electromagnetic wave irradiated from the high-frequency coil 14a on the transmission side is detected by the high-frequency coil 14b arranged close to the subject 1 and amplified by the signal amplifier 15, The quadrature phase detector 16 divides the signal into two orthogonal signals at the timing according to the command from the sequencer 4, and each signal is converted into a digital quantity by the A / D converter 17 and sent to the signal processing system 7.
Generally, the device group constituting the receiving system 6 is accommodated in a gantry 51.

  The signal processing system 7 includes an external storage device such as an optical disk 19 and a magnetic disk 18 and a display 20 made up of a CRT or the like. When data from the receiving system 6 is input to the CPU 8, the CPU 8 performs signal processing, image processing, and image processing. Processing such as reconstruction is executed, and the resulting tomographic image of the subject 1 is displayed on the display 20 and recorded on the magnetic disk 18 or the like of the external storage device. The signal processing system 7 is accommodated in the processing device 54.

  In FIG. 2, the high-frequency coil 14 and the GC 9 on the transmission side are placed facing the subject 1 in the static magnetic field space of the static magnetic field generation system 2 in which the subject 1 is inserted. The high-frequency coil 14b on the receiving side is installed so as to face or surround the subject 1.

  Currently, the radionuclide to be imaged by the MRI apparatus is a hydrogen nucleus (proton) which is a main constituent material of the subject as widely used in clinical practice. By imaging information on the spatial distribution of proton density and the spatial distribution of relaxation time in the excited state, the form or function of the human head, abdomen, limbs, etc. is imaged two-dimensionally or three-dimensionally.

  Next, a first embodiment in which the present invention is applied to the MRI apparatus will be described with reference to FIGS. FIG. 3 shows a vertical magnetic field type MRI apparatus, in which a pair of static magnetic field generation sources are vertically opposed to each other, a static magnetic field space (imaging space) is formed between them, and a subject is inserted into this space for diagnosis. The camera can be used for imaging.

  Generally, the closer to the center of the static magnetic field space, the higher the static magnetic field uniformity. When the static magnetic field uniformity is low, artifacts accompanying image quality degradation such as image distortion, blurring, and S / N reduction occur, and such artifacts are particularly noticeable in high-speed imaging methods such as the known echo planar method. For this reason, the positioning of the subject 1 is particularly important in the high-speed imaging method.

  FIG. 4 is an enlarged view of the bed 52 and the receiving coil 14b portion on which the subject 1 is placed in FIG. The couch 52 is a couchtop control unit 62 for moving the couch 56 on which the subject 1 is placed inside and outside the gantry 51 to the front, back, left and right by a motor or the like (because it is built into the couch 52 and cannot be seen from the outside. ). The top panel control unit 62 receives, for example, an instruction from the CPU 8 and controls the movement amount, movement speed, and the like of the top panel 56 in order to improve the riding comfort of the subject 1. In addition, the control of the light emitting element and the light receiving element described below and the detection signal from the light receiving element are processed to recognize the positions of the receiving coil 14b and the top plate 56. The top panel control unit 62 may be installed outside the bed 52 with emphasis on the design and maintenance of the MRI apparatus.

  An operation panel 57 for operating the movement of the top board 56 is disposed on the upper side surface of the opening of the gantry 51, and includes a switch for moving the top board 56 in the vertical direction and a switch for moving the top board 56 in the horizontal direction. Alternatively, in consideration of operability, there is a case where the foot switch 58 is supplementarily provided with a movement switch function of the top board 56 and is provided below the bed 52 or the gantry 51.

  A receiving coil 14b for receiving an NMR signal emitted from the subject 1 is attached to the imaging region of the subject 1. The closer the receiving coil 14b is to the imaging region of the subject 1, the higher the S / N ratio of the NMR signal emitted from the subject 1. In addition, when the sensitivity center of the receiving coil 14b is matched with the center of the imaging part, an image with a high S / N ratio without sensitivity unevenness can be obtained. For this reason, a receiving coil fitted to each imaging region, such as a receiving coil for the head, a receiving coil for the cervical vertebra for the cervical spine, and a receiving coil for the lumbar vertebra for the lumbar spine, is used for imaging the head.

  For the above reasons, since the sensitivity center of the receiving coil 14b and the center of the imaging region of the subject 1 are usually matched, the sensitivity center of the receiving coil 14b is sent to the center of the imaging space (center of the static magnetic field space). The setting of the imaging part of the sample 1 is completed. The receiving coil 14b receives an NMR signal from the subject 1, and a bed 59 is provided with a connector 59 for transmitting the received signal to the signal processing system 7, and a light emitting element or a light receiving element to be described later via the connector 59 Supply necessary power to

  In the present embodiment, the light emitting element is mounted on the surface of the upper surface of the receiving coil positioned on the sensitivity center of the receiving coil, and the light receiving element is mounted on the surface facing the top plate 56 above the opening of the gantry 51.

  Specifically, the infrared LED 60 is mounted on the upper surface of the receiving coil located on the sensitivity center of the receiving coil 14b, and the photo sensor 61 is placed on the surface facing the top plate 56 above the gantry 51 opening. Mount multiple units in several millimeters to several centimeters in the moving direction (perpendicular to the longitudinal direction of the top plate). In addition, the light of the infrared LED 60 is emitted through the slit so that the light has directivity. Since the distance from the photosensor 61 attached to the opening of the gantry 51 to the center of the static magnetic field space is a fixed length determined by the structure of the gantry 51, the top plate 56 after the photosensor 61 detects the position of the receiving coil 14b. The top plate control unit 62 is set in advance so that a predetermined amount of movement of the top plate 56 for sending the center to the center of the static magnetic field space can be sent in the front, rear, left and right directions.

  Based on the configuration as described above, the subject 1 is placed on the top board 56, the receiving coil 14b is mounted, the switch on the bed operation panel 57 is operated, and the top board 56 is inserted into the gantry 51. At that time, the top panel control unit 62 turns on the infrared LED 60. When the infrared LED 60 mounted on the upper surface of the receiving coil 14b passes under the photosensor 61, the photosensor 61 transmits a detection signal to the top panel control unit 62. The top panel control unit 62 recognizes the position of the receiving coil 14b in the lateral direction (direction perpendicular to the longitudinal direction of the top panel) by identifying the photo sensor that has detected the infrared signal from the plurality of photo sensors 61, and thereby The movement amount of the plate 56 is calculated, and the movement amount and movement speed of the top plate 56 are controlled, and the top plate 56 is sent into the static magnetic field space so that the sensitivity center of the receiving coil 14b comes to the center of the static magnetic field space. At that time, the top panel control unit 62 turns off the infrared LED 60.

  When the imaging is completed and the subject 1 is pulled out of the gantry 51, the operation panel 57 is operated to instruct the top panel 56 to move out of the gantry 51. At that time, the top panel control unit 62 turns on the infrared LED 60. When the infrared LED 60 mounted on the upper surface of the receiving coil 14b passes under the photosensor 61, the photosensor 61 transmits a detection signal to the top panel control unit 62. The top panel control unit 62 recognizes the position of the receiving coil 14b in the lateral direction by identifying the photo sensor that has detected the infrared signal from the plurality of photo sensors 61, and calculates the amount of movement of the top panel 56. The moving amount and moving speed of 56 are controlled to return the top board 56 to a predetermined position on the bed 52 before insertion. At that time, the top panel control unit 62 turns off the infrared LED 60.

  Since the distance from the photo sensor 61 attached to the opening of the gantry 51 to a predetermined position on the bed 52 is a fixed length determined by the structure of the gantry 51 and the bed 52, the photo sensor 61 detects the position of the receiving coil 14b. The top plate control unit 62 is set in advance so that the amount of movement of the top plate 56 for feeding the top plate 56 to the predetermined position on the bed 52 from the front, back, left and right can be sent.

  In the first embodiment described above, the mode in which the photosensor 61 is arranged as the light receiving element in the opening of the gantry 51 of the vertical magnetic field type MRI apparatus has been described. However, in this embodiment, the gantry shape is a tunnel type horizontal magnetic field type. It is also applicable to MRI equipment. In this case, since the top plate can be moved only in the front-rear direction (static magnetic field direction), the top plate is controlled only in the front-rear direction. Accordingly, it is not necessary to install a plurality of photosensors 61, and one photosensor 61 may be used.

  Next, a second embodiment in which the present invention is applied to the MRI apparatus will be described with reference to FIG. In the present embodiment, the light receiving element is mounted on the surface of the upper surface of the receiving coil positioned on the sensitivity center of the receiving coil, and the light emitting element is mounted on the top plate 56 above the opening of the gantry 51 with the configuration opposite to that of the first embodiment. It is set as the structure attached on the surface which opposes.

  Specifically, a plurality of infrared LEDs 60 are attached in increments of several millimeters to several centimeters in the lateral movement direction of the top board on the surface facing the top board 56 above the opening of the gantry 51. Similar to the first embodiment, the light of the infrared LED 60 is emitted through the slit so that the light has directivity. Further, the photo sensor 61 is attached on the surface of the upper surface of the receiving coil located on the sensitivity center of the receiving coil 14b. Further, the top panel control unit 62 performs control for switching the LED 60 to be lit at a high speed, and at the same time, determines which LED the infrared signal detected by the photosensor 61 is from. Thereby, the position information of the receiving coil 14b in the lateral direction (direction perpendicular to the longitudinal direction of the top plate) can be obtained.

  Based on the configuration as described above, the subject 1 is placed on the top board 56, the receiving coil 14b is mounted, the switch on the bed operation panel 57 is operated, and the top board 56 is inserted into the gantry 51. At that time, the top panel control unit 62 lights up the infrared LED 60 and switches the lighted LED at a high speed. When the photo sensor 61 on the receiving coil 14b passes under the infrared LED 60, the photo sensor 61 transmits a detection signal to the top panel control unit 62. The top panel control unit 62 recognizes the lighting LED 14b that matches the detection signal timing of the photo sensor 61 to recognize the lateral position of the receiving coil 14b and calculates the amount of movement of the top panel 56. Then, the moving amount and moving speed of the top plate 56 are controlled, and the top plate 56 is sent into the static magnetic field space so that the sensitivity center of the receiving coil 14b comes to the center of the static magnetic field space. At that time, the top panel control unit 62 turns off the infrared LED 60.

  When the imaging is completed and the subject 1 is pulled out of the gantry 51, the operation panel 57 is operated to instruct the top panel 56 to move out of the gantry 51. At that time, the top panel control unit 62 lights up the infrared LED 60 and switches the lighted LED at a high speed. When the photo sensor 61 mounted on the upper surface of the receiving coil 14b passes under the infrared LED 60, the photo sensor 61 transmits a detection signal to the top panel control unit 62. The top panel control unit 62 recognizes the lighting LED 14b that matches the detection signal timing of the photo sensor 61 to recognize the lateral position of the receiving coil 14b and calculates the amount of movement of the top panel 56. Then, the moving amount and moving speed of the top board 56 are controlled to return the top board 56 to a predetermined position on the bed 52 before insertion. At that time, the top panel control unit 62 turns off the infrared LED 60.

  As described above, in the first and second embodiments, a light receiving element and a light receiving element as a position detecting element are attached to the receiving coil and the gantry opening, and the movement amount of the top plate is controlled based on the detection signal. The receiving coil is controlled to be sent to the center of the static magnetic field space. This eliminates the need for a positioning projector and eliminates the need for troublesome positioning of the subject. As a result, the operability is improved, the operation time is shortened, and the subject can be set without causing discomfort to the subject. In addition, since the LED, the photosensor, and their control devices are inexpensive, the subject setting means can be configured inexpensively in the MRI apparatus.

  Next, a third embodiment in which the present invention is applied to the MRI apparatus will be described. In the first and second embodiments, infrared rays (light) are used as communication means. In the third embodiment, ultrasound (sound) is used as communication means. In this case, the light emitting element in the first and second embodiments is a sound generating element such as an ultrasonic transducer, and the light receiving element is a sound receiving element such as a microphone. The arrangement, control, and power supply of the sound generating element and the sound receiving element may be the same as those in the first and second embodiments, respectively. In other words, the sound generating element is a directional ultrasonic transducer, and a plurality of directional microphones are attached to the top of the gantry 51 opening in several millimeters to several centimeters in the lateral movement direction of the top plate. Attach to the upper surface above the sensitivity center of 14b. Or, conversely, a plurality of directional microphones are attached to the top of the gantry 51 in the horizontal direction of the top plate in several millimeters to several centimeters, and directional ultrasonic transducers are placed on the sensitivity center of the receiving coil 14b. Attach to the upper surface. In any of the above-described configurations, the insertion and withdrawal control of the top plate 56 is the same as in the first or second embodiment.

The whole block diagram of one Embodiment of an MRI apparatus. 1 is a block diagram of an embodiment of an MRI apparatus. 1 is an overall configuration diagram related to a first embodiment of an MRI apparatus to which the present invention is applied. FIG. 5 is an enlarged view of a gantry opening and a bed part of the MRI apparatus of FIG. The figure which expanded the gantry opening part and bed part regarding 2nd Embodiment of the MRI apparatus to which this invention is applied.

Explanation of symbols

  1 subject, 2 static magnetic field generation system, 3 gradient magnetic field generation system, 4 sequencer, 5 transmission system, 6 reception system, 7 signal processing system, 8 central processing unit (CPU), 9 gradient magnetic field coil, 10 gradient magnetic field power supply, 11 High-frequency transmitter, 12 Modulator, 13 High-frequency amplifier, 14a High-frequency coil (transmission coil), 14b High-frequency coil (reception coil), 15 Signal amplifier, 16 Quadrature detector, 17 A / D converter, 18 Magnetic disk, 19 Optical disk, 20 Display, 51 Gantry, 52 Table, 53 Case, 54 Processing device, 55 Power line, Signal line, 56 Top panel, 57 Operation panel, 58 Foot switch, 59 Connector, 60 Infrared LED, 61 Photo sensor

Claims (4)

A gantry including a static magnetic field generation source for forming a static magnetic field space, a bed having a top plate for placing and inserting a subject in the static magnetic field space, and a top plate mounted on the top plate In a magnetic resonance imaging apparatus comprising: a biological signal receiving means for receiving and receiving a nuclear magnetic resonance signal from the subject; and a top board control means for controlling movement of the top board,
One of the gantry and the biological signal receiving means is provided with position information transmitting means, and the other is provided with position information receiving means
The location information receiving means detects a signal from the location information sending means,
The top plate control means controls signal transmission from the position information transmission means, and based on a detection signal from the position information reception means, the position of the biological signal reception means at the time of signal detection and the static magnetic field space A magnetic resonance imaging apparatus characterized in that a distance to the center of the magnetic field space is obtained, and the top plate is moved by a distance to the center of the static magnetic field space so that the biological signal receiving means is at the center of the static magnetic field space. The magnetic resonance imaging apparatus according to claim 1.
The top board control means obtains the position of the biological signal receiving means at the time of signal detection and the distance to a predetermined position on the bed based on the detection signal from the position information receiving means, and the top board is the bed. A magnetic resonance imaging apparatus, wherein the top plate is moved by a distance to a predetermined position on the bed so as to come to a predetermined position above. The magnetic resonance imaging apparatus according to claim 1 or 2,
The magnetic resonance imaging apparatus characterized in that the positional information transmission means transmits an optical signal, and the positional information reception means receives an optical signal. The magnetic resonance imaging apparatus according to claim 1, wherein
The position information receiving means provided in the gantry is configured by arranging a plurality of position information receiving elements in a direction perpendicular to the longitudinal direction of the top plate,
The top plate control means determines the position of the biological signal receiving means with respect to a direction perpendicular to the longitudinal direction of the top board corresponding to the position information receiving element that detects the signal.

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