Wireless optical communication system and method

Abstract

To provide a wireless optical communication system and method capable of excellently performing optical communication regardless of the kind or the like of a receive coil unit attached to a subject.SOLUTION: A wireless optical communication system includes: a first optical communication device of an optical wireless module 200B connected to a receive coil unit 200 attached to a subject 102; and two or more second optical communication devices 10a to 10d that are respectively provided at a front-side position and a back-side position in a bore 120 of a gantry 110 of an MRI apparatus and are capable of performing wireless optical communication with the first optical communication device. A processor acquires link-up check information indicating which of the two or more second optical communication devices 10a to 10d is to be used by optical communication between the first optical communication device and the second optical communication devices 10a to 10d before main scanning by the MRI apparatus is started, and selects the second optical communication device to be used for the main scanning from the two or more second optical communication devices 10a to 10d based on the link-up check information and uses the selected second optical communication device.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a wireless optical communication system and method, and more particularly to a wireless optical communication system and method that is applied to a receiving coil unit attached to a subject to be imaged by a magnetic resonance imaging (MRI) apparatus. [Background technology]

[0002] A physical communication cable (coaxial cable) is connected to this type of conventional receiving coil unit.

[0003] The operator must attach the receiving coil unit to the subject placed on the bed top, connect the connector on the communication cable to the connector on the bed, and secure the subject to prevent it from moving on the top. However, the communication cable hinders the operator's setup workflow. Furthermore, the number of coaxial cables increases as the number of signals increases due to the multi-channel nature of the receiving coil, which increases the size and cost of the equipment.

[0004] Conventionally, a magnetic resonance system has been proposed that employs a wireless communication system instead of a physical communication cable (Patent Document 1).

[0005] The wireless communication system described in Patent Document 1 transmits magnetic resonance signals from an RF coil component that receives electromagnetic waves in the RF (Radio Frequency) band to a processing device via optical wireless communication, and transmits control and timing signals from a scanning control unit (scanner) to the RF coil component via optical wireless communication.

[0006] The RF coil assembly also includes a plurality of RF coil elements, and the wireless communication system includes a plurality of transmit / receive modules attached to the RF coil assembly, each module having a means for converting an optical signal to an electrical signal and a means for converting an electrical signal to an optical signal, and connected to one of the RF coil elements.

[0007] The input and output lenses of each module are each oriented to communicate with a single corresponding output and input lens of the scanner.

[0008] That is, a plurality of optical communication transmitting / receiving modules are attached to each RF coil element of the RF coil component, and a plurality of optical receivers / transmitters on the scanner side are provided at positions corresponding to the plurality of optical communication transmitting / receiving modules, and each optically communicates with the corresponding transmitting / receiving module individually. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Special Publication No. 2008-506441 Summary of the Invention [Problem to be solved by the invention]

[0010] In the wireless communication system described in Patent Document 1, multiple optical communication transmit / receive modules attached to each RF coil element of the RF coil component correspond one-to-one to multiple optical receivers / transmitters on the scanner side, and each performs optical communication individually, so it is difficult to use the multiple optical receivers / transmitters on the scanner side in common for multiple types of RF coil components (head coils, spine coils, abdominal coils, various joint coils, etc.) and for RF coil components with different numbers of RF coil elements.

[0011] The present invention has been made in consideration of the above circumstances, and aims to provide a wireless optical communication system and method that can perform optical communication well regardless of the type of receiving coil unit attached to the subject. [Means for solving the problem]

[0012] The invention according to a first aspect is a wireless optical communication system comprising: a first optical communication device connected to a receiving coil unit attached to a subject; two or more second optical communication devices provided at a front position and a back position within the bore of a gantry of a magnetic resonance imaging device, each capable of wireless optical communication with the first optical communication device; and a processor that controls the optical communication between the first optical communication device and the second optical communication devices, wherein the processor executes optical communication between the first optical communication device and the second optical communication device before a main scan is started by the magnetic resonance imaging device, obtains link-up check information through the optical communication indicating which of the two or more second optical communication devices should be used, selects a second optical communication device to be used for the main scan from among the two or more second optical communication devices based on the link-up check information, and when the main scan is started, executes optical communication between the first optical communication device and the selected second optical communication device, and obtains a nuclear magnetic resonance signal received by the second optical communication device through the optical communication.

[0013] According to the first aspect of the present invention, by obtaining link-up check information indicating which of two or more second optical communication devices should be used through optical communication before the main scan, it is possible to select a second optical communication device that can perform good optical communication with the first optical communication device during the main scan and perform optical communication (obtain good nuclear magnetic resonance signals).

[0014] In the wireless optical communication system according to the second aspect of the present invention, in the first aspect, the link-up check information is preferably an offset position of the first optical communication device relative to a reference position of the receiving coil unit, or a type or model number of the receiving coil unit.

[0015] When the reference position of the receiving coil unit is controlled to move to the center of the imaging area within the bore, the offset position of the first optical communication device indicates the relative position of the first optical communication device with respect to the center of the imaging area within the bore, and once the position of the first optical communication device within the bore is known, it is possible to select a second optical communication device within the bore that is capable of optimal optical communication with the first optical communication device.

[0016] In a wireless optical communication system according to a third aspect of the present invention, in the first aspect, the link-up check information is the reception strength received by each of two or more second optical communication devices, and it is preferable that the processor performs a pre-scan using two or more second optical communication devices before starting the main scan, and during the pre-scan, selects a second optical communication device to be used for the main scan based on the reception strength received by each of the two or more second optical communication devices.

[0017] According to the third aspect of the present invention, it is possible to select the optimum second optical communication device with the maximum reception strength based on the reception strengths received by two or more second optical communication devices through pre-scanning.

[0018] In a wireless optical communication system according to a fourth aspect of the present invention, in any of the first to third aspects, the receiving coil unit preferably includes a memory that stores an offset position of the first optical communication device relative to a reference position of the receiving coil unit or a type or model number of the receiving coil unit, and the processor preferably reads out the offset position or the type or model number of the receiving coil unit from the memory by optical communication before the start of the main scan.

[0019] In the wireless optical communication system according to the fifth aspect of the present invention, in the fourth aspect, when the processor acquires the type or model number of the receiving coil unit, it is preferable to acquire information indicating an offset position set according to the type or model number of the receiving coil unit, or one second optical communication device to be used for the main scan.

[0020] If the type or model number of the receiving coil unit can be obtained, it is possible to obtain an offset position corresponding to the type or model number of the receiving coil unit that has been stored in memory in advance based on the obtained type or model number of the receiving coil unit, and similarly, it is also possible to directly obtain information indicating which of two or more second optical communication devices should be used during the actual scan.

[0021] In a wireless optical communication system according to a sixth aspect of the present invention, in the fourth or fifth aspect, the processor preferably acquires position information of the first optical communication device on the top plate of the bed on which the subject is placed, based on two or more received signals respectively received by two or more second optical communication devices through optical communication before the start of the main scan. This position information of the first optical communication device can be used to control the position of the top plate of the bed when feeding it into the bore.

[0022] A wireless optical communication system according to a seventh aspect of the present invention is the second aspect, and preferably includes a third optical communication device capable of wireless optical communication with the first optical communication device of the receiving coil unit before the start of movement of the top of a bed on which a subject is placed, and the processor executes optical communication between the first optical communication device and the third optical communication device before the start of a main scan, and acquires the offset position of the first optical communication device relative to a reference position of the receiving coil unit, or the type or model number of the receiving coil unit. This makes it possible to successfully acquire the offset position of the first optical communication device or the type or model number of the receiving coil unit through optical communication by the third optical communication device before the top of the bed is moved.

[0023] In a wireless optical communication system according to an eighth aspect of the present invention, in the seventh aspect, it is preferable that the third optical communication device is provided on the ceiling above the bed.

[0024] In the wireless optical communication system according to the ninth aspect of the present invention, in any of the first to eighth aspects, it is preferable that the processor acquires information used to control the position of the table top on which the subject is placed by optical communication before the start of the main scan, and automatically or manually controls the position of the table top to be sent into the bore based on the acquired information, and moves the receiving coil unit to the imaging area within the bore.

[0025] In the wireless optical communication system according to the tenth aspect of the present invention, in the sixth aspect, the processor preferably controls the position of the tabletop based on the acquired position information and offset position to move the reference position of the receiving coil unit to the center of the imaging area in the bore of the gantry, or outputs assist information for manually moving the tabletop, the assist information moving the reference position of the receiving coil unit to the center of the imaging area.

[0026] According to the tenth aspect of the present invention, the reference position of the receiving coil unit relative to the top plate can be determined from the position information of the first optical communication device on the top plate and the offset position of the first optical communication device relative to the reference position of the receiving coil unit.This allows the amount of movement of the top plate required to move the reference position of the receiving coil unit to the center of the imaging area in the bore to be determined, and the top plate can be automatically controlled based on the determined amount of movement so that the reference position of the receiving coil unit is at the center of the imaging area in the bore.Alternatively, by presenting assist information indicating the difference between the current reference position of the coil unit and the center of the imaging area, the operator can manually control the position of the top plate so that the reference position of the coil unit is at the center of the imaging area.

[0027] In a wireless optical communication system according to an eleventh aspect of the present invention, in any of the first to tenth aspects, it is preferable that the processor acquires link-up check information at each repetition period of the main scan or at each of multiple repetition periods of the main scan.

[0028] A twelfth aspect of the invention is a wireless optical communication method in a wireless optical communication system including a first optical communication device connected to a receiving coil unit attached to a subject, two or more second optical communication devices provided at a front position and a back position within a bore of a gantry of a magnetic resonance imaging device and capable of wireless optical communication with the first optical communication device, and a processor controlling the optical communication between the first optical communication device and the second optical communication devices, the wireless optical communication method including the steps of: executing optical communication between the first optical communication device and the second optical communication device before a main scan is started by the magnetic resonance imaging device, and obtaining link-up check information indicating which of the two or more second optical communication devices should be used by the optical communication; selecting a second optical communication device to be used for the main scan from the two or more second optical communication devices based on the link-up check information; and, once the main scan is started, executing optical communication between the first optical communication device and the selected second optical communication device, and obtaining a nuclear magnetic resonance signal received by the second optical communication device by the optical communication. [Effects of the Invention]

[0029] According to the present invention, of two or more optical communication devices (second optical communication devices) provided at the front and back positions within the bore of the gantry of a magnetic resonance imaging device, a second optical communication device that can perform good optical communication with the optical communication device (first optical communication device) of a receiving coil unit attached to a subject can be automatically selected, thereby enabling good optical communication with the first optical communication device of the receiving coil unit when performing a main scan, regardless of the type of receiving coil unit, etc. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1 is a perspective view showing the appearance of a magnetic resonance imaging apparatus (MRI apparatus) to which a wireless optical communication system according to the present invention is applied. [Figure 2] FIG. 2 is a diagram showing a schematic internal configuration of the MRI apparatus shown in FIG. [Figure 3]FIG. 3 is a schematic diagram showing the configuration of the receiving coil unit. [Figure 4] FIG. 4 is a block diagram showing the internal configuration of the optical wireless module shown in FIG. [Figure 5] FIG. 5 is a block diagram showing a second optical communication device provided on the gantry of the MRI apparatus and a processor that transmits and receives electrical signals to and from the second optical communication device. [Figure 6] FIG. 6 is a diagram showing the positional relationship between the first optical communication device of the receiving coil unit and four second optical communication devices arranged in the bore of the gantry of the MRI apparatus before a main scan by the MRI apparatus. [Figure 7] FIG. 7 is a diagram showing the positional relationship between the first optical communication device of the receiving coil unit and four second optical communication devices arranged in the bore of the gantry of the MRI apparatus during a main scan by the MRI apparatus. [Figure 8] FIG. 8 is a flowchart illustrating an embodiment of a wireless optical communication method according to the present invention. [Figure 9] FIG. 9 is a subroutine showing an example of the process of step S10 shown in FIG. [Figure 10] FIG. 10 is a diagram showing an example of a pulse sequence of the MRI apparatus. [Figure 11] FIG. 11 is a diagram showing another example of a pulse sequence of the MRI apparatus. [Figure 12] FIG. 12 is a diagram showing the positional relationship between the first optical communication device of the receiving coil unit and the third optical communication device provided on the ceiling before a main scan by the MRI apparatus. [Figure 13] Figure 13 shows the positional relationship between the first optical communication device of the receiving coil unit, the four second optical communication devices arranged in the bore of the gantry of the MRI device, and the third optical communication device installed on the ceiling of the examination room during the main scan using the MRI device. DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, preferred embodiments of a wireless optical communication system and method according to the present invention will be described with reference to the accompanying drawings.

[0032] FIG. 1 is a perspective view showing the appearance of a magnetic resonance imaging apparatus (MRI apparatus) to which a wireless optical communication system according to the present invention is applied.

[0033] The MRI apparatus 100 shown in FIG. 1 includes a gantry 110 and a bed 130 having a top plate 130A arranged in front of a bore 120, which is a cylindrical imaging space provided in the gantry 110.

[0034] [Internal structure of an MRI device] FIG. 2 is a diagram showing a schematic internal configuration of the MRI apparatus shown in FIG.

[0035] As shown in FIG. 2, the MRI apparatus 100 includes a static magnetic field generating magnet 104 that generates a uniform static magnetic field in an imaging space in which a subject 102 is placed, a gradient coil (GC: Gradient Coil) 106 that generates a gradient magnetic field pulse in the imaging space, an RF (Radio Frequency) coil (transmitting coil) 108 that generates a high frequency magnetic field that generates a nuclear magnetic resonance signal (NMR (Nuclear Magnetic Resonance) signal) (NMR signal) in the nuclei of atoms that constitute the tissue of the subject 102, and a receiving coil unit 200 that detects the NMR signal generated from the subject 102.

[0036] As shown in Figures 1 and 2, the subject 102 is lying on his back on the top plate 130A of the bed 130, and by moving the top plate 130A into the bore 120, the examination area of ​​the subject 102 is moved so that it is positioned in the imaging area (center of the static magnetic field) within the bore 120.

[0037] The sequencer 118 sends commands to the radio frequency magnetic field generator 112 and the gradient magnetic field power supply 116 in accordance with an imaging sequence (pulse sequence), causing them to generate a radio frequency magnetic field and a gradient magnetic field, respectively. The generated radio frequency magnetic field is applied to the subject 102 as a pulsed radio frequency magnetic field (RF pulse) through the transmitting coil 108. The NMR signal generated from the subject 102 is received by a receiving coil 200A (see FIG. 3 ) constituting the receiving coil unit 200, and is subjected to signal processing such as amplification and A / D conversion by an optical wireless module 200B connected to the receiving coil 200A and functioning as a first optical communication device, after which the signal is converted into an optical signal and wirelessly transmitted.

[0038] The second optical communication devices 10 (10a to 10d) are two or more optical communication devices provided at a position on the front ceiling and a position on the back ceiling within the bore 120 of the gantry 110, and are configured by four second optical communication devices 10a to 10d in this example. Each of the four second optical communication devices 10a to 10d performs optical communication with the optical wireless module 200B that functions as the first optical communication device. Note that, for convenience of explanation, the second optical communication devices 10 (10a to 10d) are positioned outside the bore 120 in FIG. 2, but they are actually disposed within the bore 120 of the gantry 110 as will be described in detail in FIGS. 6 and 7.

[0039] The receiving coil unit 200 and the second optical communication devices 10a to 10d will be described in detail later.

[0040] The gradient magnetic field coil 106 is composed of gradient magnetic field coils in three directions, X, Y, and Z, and generates gradient magnetic fields in response to signals from a gradient magnetic field power supply 116 .

[0041] The optical signal representing the NMR signal received by the second optical communication device 10 is photoelectrically converted and output to the control unit 140. The sequencer 118 controls each unit so that it operates at pre-programmed timing and intensity. The program, which particularly describes the timing and intensity of RF pulses, gradient magnetic fields, and signal reception, is called a pulse sequence.

[0042] There are various known pulse sequences depending on the purpose, but a detailed description thereof will be omitted here.

[0043] The control unit 140 controls the operation of the MRI apparatus 100 via the sequencer 118, receives the NMR signal from the second optical communication device 10, and performs various signal processing such as image reconstruction.

[0044] The control unit 140 can be configured using a computer. The computer applied to the control unit 140 may be a personal computer or a workstation.

[0045] The control unit 140 receives various instruction inputs from the operation unit 150, controls each part of the MRI device 100, and performs processes such as converting the NMR signal (echo signal) input from the second optical communication device 10 into an image of real space by inverse Fourier transform, thereby generating an MRI image.

[0046] The operation unit 150 includes a mouse, a keyboard, and the like, and functions as part of a GUI (Graphical User Interface) that uses a display operation window on a display (not shown) to accept input from an operator.

[0047] That is, the operation unit 150 and the display function as a GUI for the operator to start and stop (pause) the MRI apparatus 100, select a pulse sequence, and input imaging conditions, processing conditions, and the like.

[0048] [Receiving coil unit] FIG. 3 is a schematic diagram showing the configuration of the receiving coil unit.

[0049] As shown in FIG. 3, the receiver coil unit 200 is composed of a receiver coil 200A and an optical wireless module 200B.

[0050] The receiving coil 200A is flexible, thin, and lightweight, and can cover a wide imaging range, and can image various regions to be examined.

[0051] The receiver coil 200A shown in FIG. 3 has a plurality of loop-shaped coil elements 202 arranged therein, each of which functions as an antenna for receiving a nuclear magnetic resonance signal (NMR signal).

[0052] The optical wireless module 200B has a connector 210 that is connected to the connector 204 of the receiving coil 200A, and is configured to be connectable in place of a communication cable (not shown). Note that the optical wireless module 200B is not limited to being detachable from the receiving coil 200A, and may be integrated with the receiving coil 200A. Furthermore, the receiving coil 200A and the optical wireless module 200B may be connected by a communication cable.

[0053] 3, the optical wireless module 200B includes an E / O optical transmitter 224 that functions as an E / O (Electrical signal / Optical signal) converter, and an O / E optical receiver 226 that functions as an O / E (Optical signal / Electrical signal) converter. In this example, the E / O optical transmitter 224 and the O / E optical receiver 226 are collectively referred to as a "first optical communication device 227."

[0054] The receiving coil 200A has 15 coil elements 202 arranged in 5 rows and 3 columns, and the reference position O of the receiving coil 200A (receiving coil unit 200) in this example is the center position of the coil element 202 arranged at the center of the 15 coil elements 202.

[0055] 3. The position (offset position) of the first optical communication device 227 relative to this reference position O is a position spaced a distance L to the right in FIG.

[0056] 3, in the case of an xy coordinate system based on the reference position O of the receive coil 200A, the offset position of the first optical communication device 227 can be expressed by the coordinates (L, 0). Note that the x-axis of the xy coordinate system is the direction of movement when the receive coil unit 200 is set on the subject 102 on the top board 130A of the bed 130, and the receive coil unit 200 is sent into the bore 120 together with the subject 102 by moving the top board 130A.

[0057] [Configuration of optical wireless module] FIG. 4 is a block diagram showing the internal configuration of the optical wireless module shown in FIG.

[0058] The optical wireless module 200B shown in FIG. 4 is composed of a connector 210, a preamplifier 212, a filter 214, an A / D (Analog / Digital) converter 216, a decimation 218, a multiplexer 220, a memory 222, a first optical communication device 227 including an E / O optical transmitter 224 and an O / E optical receiver 226, a demultiplexer 228, and a battery 230.

[0059] As described in FIG. 3, connector 210 is connected to connector 204 of receiving coil 200A, receives analog nuclear magnetic resonance signals (NMR signals) from receiving coil 200A, and also supplies driving power from battery 230 to a decoupling circuit (not shown) of receiving coil 200A and the like.

[0060] Analog NMR signals input in parallel from the 15 coil elements 202 of the receiving coil 200A via connector 210 are each amplified by a preamplifier 212, and signal components in the desired resonance frequency band are extracted by a filter 214 and added to an A / D converter 216.

[0061] The A / D converter 216 receives the sampling clock of the A / D converter 216 from the control signals of each control destination that have been serial / parallel converted by the demultiplexer 228, and the A / D converter 216 converts the analog NMR signal into a digital NMR signal in accordance with the sampling clock and outputs it to the decimation 218.

[0062] Decimation 218 averages the digitized NMR signals, converts them into low-speed multi-bit signals, and outputs them to multiplexer 220. Multiplexer 220 time-division multiplexes the multiple NMR signals, for example, and outputs them as a single signal.

[0063] The NMR signal output from multiplexer 220 is applied to memory 222 and E / O optical transmitter 224 .

[0064] The E / O optical transmitter 224 converts the NMR signal input from the multiplexer 220 into an optical signal and emits (transmits) the converted optical signal. The E / O optical transmitter 224 has, for example, a light-emitting diode (preferably an infrared light-emitting diode), and emits the NMR signal light converted into an optical signal from the light-emitting diode driven based on the NMR signal, which is an electrical signal, and the NMR signal light emitted from the light-emitting diode is emitted with an appropriate angle of view by a projection lens.

[0065] The memory 222 temporarily stores the transmission data in preparation for a communication failure, and outputs the transmission data (NMR signal) to the E / O optical transmitter 224 in response to a data request.

[0066] The memory 222 also stores link-up check information indicating which of the two or more second optical communication devices 10a to 10d should be used as the second optical communication device 10 that optically communicates with the first optical communication device 227 during a main scan by the MRI apparatus 100. Here, the link-up check information may be the offset position of the first optical communication device 227 with respect to the reference position O of the receiving coil unit 200 shown in FIG. 3 (see FIG. 3), or the type or model number of the receiving coil unit 200.

[0067] If information on the type or model number of the receive coil unit 200 can be acquired, then based on the type or model number of the receive coil unit acquired information, it is possible to acquire the corresponding offset position from a table showing the relationship between information on the type or model number of the receive coil unit and the offset position, which is stored in advance in a memory other than the memory 222. Furthermore, on the premise that the reference position of the receive coil unit is positioned at the center of the imaging area in the bore, the relationship between the type or model number of the receive coil unit and the second optical communication device to be used from two or more second optical communication devices in the bore may be stored in advance in a memory, and the movement position to which the second optical communication device should move during the main scan may be acquired based on the type or model number of the receive coil unit.

[0068] The O / E optical receiver 226 of the optical wireless module 200B receives various control signals (serialized control signals such as a sampling clock for the A / D converter 216, an operation setting control signal, a digital signal processing setting control signal in the decimation 218, a gain setting control signal for the preamplifier 212, and a decoupling control signal for the decoupling circuit of the receiving coil 200A) from the processor 20 of the MRI apparatus 100 shown in Fig. 5 via the second optical communication device 10 and converts them into electrical signals. The O / E optical receiver 226 has, for example, a focusing lens and a photoelectric conversion element that converts the optical signal focused by the focusing lens into an electrical signal, and outputs the various serialized control signals converted by the photoelectric conversion element to the demultiplexer 228.

[0069] The demultiplexer 228 performs serial / parallel conversion on the various serialized control signals, and sends out the parallelized control signals as control signals for each control destination.

[0070] Battery 230 is a battery that is built into optical wireless module 200B and can be charged by power supplied from charging port 232, and supplies power to each circuit within optical wireless module 200B, as well as to receiving coil 200A via connector 210.

[0071] FIG. 5 is a block diagram showing a second optical communication device provided on the gantry of the MRI apparatus, and a processor that transmits and receives electrical signals to and from the second optical communication device.

[0072] The processor 20 shown in FIG. 5 is a part that executes the wireless optical communication method according to the present invention, and the control unit 140 shown in FIG.

[0073] The processor 20 executes optical communication between the first optical communication device 227 and the second optical communication device 10 before the start of the main scan by the MRI apparatus 100, acquires link-up check information through this optical communication indicating which of the two or more second optical communication devices 10a to 10d should be used, selects a second optical communication device to be used for the main scan from the two or more second optical communication devices 10a to 10d based on the acquired link-up check information, and when the main scan starts, executes optical communication between the first optical communication device 227 and the selected second optical communication device 10, and acquires a nuclear magnetic resonance signal (NMR signal) received by the second optical communication device 10 through this optical communication.

[0074] The above processing by the processor 20 will be described in detail later.

[0075] 5, the second optical communication device 10a includes an O / E optical receiver 12 and an E / O optical transmitter 14. The O / E optical receiver 12 and the E / O optical transmitter 14 are configured similarly to the O / E optical receiver 226 and the E / O optical transmitter 224 shown in FIG.

[0076] When the first optical communication device 227 of the receive coil unit 200 performs optical communication with the second optical communication device 10a provided on the gantry 110, the O / E optical receiver 12 receives the serialized NMR signal transmitted from the E / O optical transmitter 224 of the first optical communication device 227, converts it into an electrical signal, and outputs it to the processor 20. The E / O optical transmitter 14, which receives various serialized control signals from the processor 20, converts it into an optical signal and transmits it. The various serialized optical signals transmitted from the E / O optical transmitter 14 are received by the O / E optical receiver 226 of the receive coil unit 200 and converted into an electrical signal there.

[0077] The second optical communication devices 10b, 10c, and 10d are configured in the same manner as the second optical communication device 10a, and communication with the processor 20 is performed in the same manner as the second optical communication device 10a.

[0078] These four second optical communication devices 10a, 10b, 10c, and 10d are arranged at different positions on the gantry 110.

[0079] [Positional relationship between the first optical communication device and the second optical communication device] <Condition before main scan> FIG. 6 is a diagram showing the positional relationship between the first optical communication device of the receiving coil unit and four second optical communication devices arranged in the bore of the gantry of the MRI apparatus before a main scan by the MRI apparatus.

[0080] Here, the main scan refers to imaging of the subject 102 using the MRI device 100, and before the main scan shown in Figure 6 refers to a state in which the subject 102 is placed on the top plate 130A of the bed 130, the setting of the receiving coil unit 200 on the subject 102 is completed, and before the operation of moving the top plate 130A to send the subject 102 into the bore 120 begins.

[0081] Figure 6(A) is a diagram showing the side of the gantry 110 and bed 130 of the MRI device, Figure 6(B) is a left side view of Figure 6(A) as seen from the entrance side (bed side) of the bore 120, and Figure 6(C) is a right side view of Figure 6(A) as seen from the opposite side of the bore 120.

[0082] The second optical communication devices 10a and 10b are installed at the front (entrance) side of the bore 120 of the gantry 110 as shown in Figures 6(A) and (B), and are arranged on the left and right sides of the ceiling part of the bore 120 as shown in Figure 6(B).

[0083] The second optical communication devices 10c and 10d are installed at the deep end of the bore 120 of the gantry 110 as shown in Figures 6(A) and (C), and are arranged on the left and right sides of the ceiling part of the bore 120 as shown in Figure 6(C).

[0084] <Status at the time of main scan> FIG. 7 is a diagram showing the positional relationship between the first optical communication device of the receiving coil unit and four second optical communication devices arranged in the bore of the gantry of the MRI apparatus during a main scan by the MRI apparatus.

[0085] 7(A) to 7(C) are figures corresponding to FIGS. 6(A) to 6(C), respectively, and the position of the top board 130A of the bed 130 (i.e., the position of the subject 102 and the receiving coil unit 200) is different from that in FIGS. 6(A) to 6(C).

[0086] When performing a main scan using an MRI apparatus, the top board 130A of the bed 130 is sent into the bore 120 of the gantry 110, and the reference position O (see FIG. 3) of the receive coil unit 200 set on the subject 102 is moved to the center of the imaging area in the bore 120 of the gantry 110, after which the main scan is performed. In the example shown in FIG. 7, during the main scan, the second optical communication device 10a is linked up with the first optical communication device of the receive coil unit 200 (optical wireless module 200B), and optical communication of information including NMR signals and the like is performed.

[0087] [Wireless optical communication method] Next, a wireless optical communication method according to the present invention will be described.

[0088] FIG. 8 is a flowchart showing an embodiment of a wireless optical communication method according to the present invention, and the processor 20 shown in FIG. 5 executes a program relating to the wireless optical communication method to implement the wireless optical communication method.

[0089] In FIG. 8, the processor 20 performs control to send the top board 130A of the bed 130 into the bore 120 of the gantry 110 and move the receive coil unit 200 to the imaging area in the bore 120 (step S10).

[0090] FIG. 9 is a subroutine showing an example of the process of step S10 shown in FIG.

[0091] 9, in step S12, the offset position of the first optical communication device 227 relative to the reference position of the receiving coil unit 200 is acquired as link-up check information. That is, the processor 20 causes the second optical communication device 10a to transmit an "offset position acquisition request" via E / O light to the first optical communication device 227 of the receiving coil unit 200, and the first optical communication device 227 reads information indicating the offset position stored in the memory 222 in accordance with the "offset position acquisition request" received via O / E light, and transmits the information indicating the offset position via E / O light. The processor 20 acquires information indicating the offset position received via O / E light by the second optical communication device 10a.

[0092] 6, the second optical communication devices 10a, 10b on the bed side of the bore 120 are closer than the second optical communication devices 10c, 10d on the deeper side of the bore 120, and therefore the closer second optical communication device 10a was used for optical communication for link-up check information, but the second optical communication device 10b may also be used, and further, if link-up is possible with multiple second optical communication devices 10, it is preferable to obtain multiple pieces of link-up check information from the multiple second optical communication devices 10 that are link-up possible. In this case, the processor 20 compares the multiple pieces of link-up check information, and if there is a difference, it can determine which is correct.

[0093] Next, the processor 20 acquires position information of the first optical communication device 227 (optical wireless module 200B) on the tabletop 130A on which the object 102 is placed (step S14).

[0094] The position information of the first optical communication device 227 can be obtained, for example, by transmitting an optical signal of a set optical intensity from the first optical communication device 227 and based on the signal intensity of the optical signal (received signal) received by one or more second optical communication devices 10. In this case, a table showing the reception intensity of the optical signal received by one or more second optical communication devices 10 for each position of the first optical communication device 227 is created in advance, and the position information of the first optical communication device 227 can be obtained by using the table. Furthermore, the position information of the first optical communication device 227 can be obtained from the position of the optical wireless module 200B (first optical communication device 227) on an image captured by a ceiling camera (not shown).

[0095] Next, the processor 20 controls the position of the tabletop 130A based on the offset position and position information acquired in steps S12 and S14, and moves the reference position of the receive coil unit 200 to the center of the imaging area in the bore 120 of the gantry 110 (step S16).

[0096] 6 from the acquired offset position and position information, the processor 20 can determine the reference position of the receive coil unit 200 at the position of the tabletop 130A in the state shown in Fig. 6, and can also determine the amount of movement of the tabletop 130A required to move this reference position to the center of the imaging area in the bore 120. Therefore, the processor 20 can automatically move the reference position of the receive coil unit 200 to the center of the imaging area in the bore 120 by performing position control of the tabletop 130A to move the tabletop 130A by the determined amount of movement.

[0097] Furthermore, when the tabletop 130A is moved by manual operation, the processor 20 may output, to an operation display or the like, assist information for moving the reference position of the receiving coil unit 200 to the center of the imaging region. The assist information may be information indicating the difference between the amount of movement calculated as described above and the amount of movement of the tabletop 130A by manual operation.

[0098] Returning to Figure 8, after the reference position of the receiving coil unit 200 is controlled to move to the center of the imaging area within the bore 120 as shown in Figure 7, the processor 20 performs optical communication (pre-scan) between the first optical communication device 227 and the four second optical communication devices 10 (10a to 10d) before starting the main scan, and acquires link-up check information (step S20).

[0099] In this case, the link-up check information can be, for example, the reception intensity of the optical signal transmitted E / O optically from the first optical communication device 227 of the receiving coil unit 200 in the bore 120, as received O / E optically by each of the four second optical communication devices 10a to 10d.

[0100] The processor 20 selects one second optical communication device to be used for the main scan from among the four second optical communication devices 10 (10a to 10d) based on the link-up check information acquired in step S20 (step S30). That is, the processor 20 preferably compares the reception conditions of each reception signal received by the four second optical communication devices 10a to 10d via O / E light, and selects the one second optical communication device 10 with the best reception condition. For example, the processor 20 can calculate the reception strength of each reception signal received by the four second optical communication devices 10a to 10d via O / E light, and select the second optical communication device with the greatest reception strength.

[0101] 9, the processor 20 can determine the position (relative position) of the first optical communication device 227 with respect to the center of the imaging area in the bore 120 when the reference position of the receiving coil unit 200 is moved to the center of the imaging area in the bore 120. Therefore, instead of the processes of steps S20 and S30, the processor 20 can select an optimal second optical communication device from the four second optical communication devices 10a to 10d based on the relative position of the first optical communication device 227 in the bore 120.

[0102] Thereafter, upon receiving an instruction to start imaging from the operation unit 150, the control unit 140 of the MRI apparatus 100 starts a main scan according to the imaging sequence via the sequencer 118 (step S40). During the main scan, the processor 20 performs optical communication between the first optical communication device 227 and the second optical communication device 10 selected in step S30, and acquires a nuclear magnetic resonance signal (NMR signal) received by the second optical communication device 10 through this optical communication (step S50).

[0103] The control unit 140 determines whether the main scan has ended (step S60). If the main scan is still ongoing (if "No"), the control unit 140 repeatedly acquires NMR signals from step S50, and if the main scan has ended (if "Yes"), the control unit 140 causes the MRI apparatus 100 to end the imaging operation.

[0104] <Link-up of the second optical communication device during main scan> The processor 20 performs a pre-scan (pre-scan) before the actual scan by the MRI apparatus 100 to perform optical communication between the optical wireless module 200B (first optical communication device 227) arranged in the receiving coil unit 200 and multiple second optical communication devices 10 (10a to 10d) installed in the bore 120, detects which of the multiple second optical communication devices 10 (10a to 10d) has the strongest reception strength, and first selects the second optical communication device 10 that is easiest to link up with based on the detection result.The selected second optical communication device 10 is used during the actual scan, but it is preferable to also check for link up during the actual scan.

[0105] This is because it is possible that the relative position of the receiving coil unit 200 (first optical communication device 227) to the center of the imaging area in the bore 120 may fluctuate due to movement of the subject 102 during the main scan, or that a malfunction may occur in the currently selected second optical communication device 10.

[0106] Therefore, it is preferable that the processor 20 obtains link-up check information during the main scan and links up with the second optical communication device 10 with a better communication situation.

[0107] FIG. 10 is a diagram showing an example of a pulse sequence of the MRI apparatus.

[0108] As shown in Figure 10, the sequence repeatedly generates excitation RF pulses, GC pulses, etc. at time intervals of TR (time to repeat), and collects NMR signals (not shown) as echo signals from the receiving coil, but obtains link-up check information every TR cycle.

[0109] The link-up check information here is the reception intensity of the optical signal received by each of the four second optical communication devices 10a to 10d when the first optical communication device 227 transmits an optical signal of the set optical intensity.

[0110] The processor 20 selects the second optical communication device 10 with the strongest reception strength based on the link-up check information acquired every TR cycle, and in the next TR cycle, links up the second optical communication device 10 selected in the previous TR cycle and acquires the echo signal.

[0111] FIG. 11 is a diagram showing another example of a pulse sequence of an MRI apparatus, which differs from the sequence shown in FIG. 10 in particular in the timing of acquiring link-up check information.

[0112] That is, in the sequence shown in FIG. 10, link-up check information is acquired every TR cycle, but in the sequence shown in FIG. 11, link-up check information is acquired in a thinned manner, such as once every several TR cycles, and link-up is confirmed.

[0113] <Another embodiment of acquiring link-up check information before main scan> FIG. 12 is a diagram showing the positional relationship between the first optical communication device of the receiving coil unit and the third optical communication device provided on the ceiling before a main scan by the MRI apparatus.

[0114] Figure 12(A) is a diagram showing the side of the gantry 110 and bed 130 of the MRI device, Figure 12(B) is a left side view of Figure 12(A) as seen from the entrance side (bed side) of the bore 120, and Figure 12(C) is a right side view of Figure 12(A) as seen from the opposite side of the bore 120.

[0115] As shown in FIG. 12, the third optical communication device 10e is provided on the ceiling above the bed 130 in the examination room in which the MRI apparatus 100 is installed.

[0116] The third optical communication device 10e is an optical communication device that has the same functions as the four second optical communication devices 10a to 10d installed in the ceiling portion inside the bore 120, but its use differs from that of the four second optical communication devices 10a to 10d in that it is used to obtain link-up check information before the main scan and is not used during the main scan.

[0117] As shown in FIG. 12, the third optical communication device 10e performs optical communication with the optical wireless module 200B (first optical communication device 227) of the receiving coil unit 200 in the state before the setting of the receiving coil unit 200 on the subject 102 is completed and the operation of feeding the subject 102 into the bore 120 by moving the top plate 130A is started (the state before the main scan), and the processor 20 obtains link-up check information from the third optical communication device 10e indicating which of the two or more second optical communication devices 10a to 10d should be used during the main scan.

[0118] The processor 20 may also acquire link-up check information from the second optical communication devices 10 (10a to 10d) that are capable of linking up before the main scan, including the third optical communication device 10e, and is not limited to the third optical communication device 10e.

[0119] Furthermore, the third optical communication device 10e is not limited to being provided on the ceiling of the examination room, but may be embedded in the bed 130 or the top board 130A.

[0120] Figure 13 shows the positional relationship between the first optical communication device of the receiving coil unit, the four second optical communication devices arranged in the bore of the gantry of the MRI device, and the third optical communication device installed on the ceiling of the examination room during the main scan using the MRI device.

[0121] Figures 13(A) to (C) are figures corresponding to Figures 12(A) to (C), respectively, and the position of the top board 130A of the bed 130 (i.e., the positions of the subject 102 and the receive coil unit 200) differs from that in Figures 12(A) to (C).

[0122] For the actual scan by the MRI apparatus 100, the second optical communication device 10a is linked up with the first optical communication device of the receiving coil unit 200 (optical wireless module 200B), and optical communication of information including NMR signals and the like is performed.

[0123] [others] The receiving coil unit is equipped with an optical wireless module that functions as a first optical communication device, but the configuration of this optical wireless module is not limited to this embodiment and may be any module that performs wireless optical communication with the second optical communication device.

[0124] In addition, in this embodiment, two second optical communication devices are provided at the front ceiling position and two at the back ceiling position within the gantry bore (four in total), but the number and placement positions of the second optical communication devices are not limited to this, and the two or more second optical communication devices may be provided at least at different positions in the depth direction within the bore.

[0125] Furthermore, in this embodiment, the hardware structure of a processing unit that executes various processes, such as a CPU, is various processors as follows: The various processors include a CPU (Central Processing Unit), which is a general-purpose processor that executes software (programs) and functions as various processing units, a programmable logic device (PLD), such as an FPGA (Field Programmable Gate Array), whose circuit configuration can be changed after manufacture, and a dedicated electrical circuit, such as an ASIC (Application Specific Integrated Circuit), which is a processor with a circuit configuration designed specifically for executing specific processes.

[0126] A single processing unit may be configured with one of these various processors, or may be configured with two or more processors of the same or different types (for example, multiple FPGAs, or a combination of a CPU and an FPGA). Also, multiple processing units may be configured with a single processor. Examples of multiple processing units configured with a single processor include, first, a configuration in which one processor is configured with a combination of one or more CPUs and software, as typified by client or server computers, and this processor functions as multiple processing units. Second, a configuration in which a processor is used to realize the functions of an entire system including multiple processing units on a single IC (Integrated Circuit) chip, as typified by a System on Chip (SoC). In this way, the various processing units are configured with one or more of the above-mentioned various processors as a hardware structure.

[0127] Furthermore, the hardware structure of these various processors is, more specifically, an electric circuit made up of a combination of circuit elements such as semiconductor elements.

[0128] Furthermore, the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications are possible without departing from the spirit of the present invention. [Explanation of symbols]

[0129] 10, 10a, 10b, 10c, 10d...Second optical communication device 10e...Third optical communication device 12...O / E optical receiver 14…E / O optical transmitter 20...Processor 100...MRI device 102...Subject 104...Static magnetic field generating magnet 106...Gradient magnetic field coil 108...Transmitting coil 110...Gantry 112...High frequency magnetic field generator 116...Gradient magnetic field power supply 118...Sequencer 120…bore 130...Bed 130A...top plate 140...Control unit 150...Operation unit 200...Receiving coil unit 200A...receiving coil 200B... Optical wireless module 202...Coil element 204, 210... connector 212...Preamp 214...Filter 216...A / D converter 218...Decimation 220...Multiplexer 222...Memory 224...E / O optical transmitter 226...O / E optical receiver 227...First optical communication device 228...Demultiplexer 230…Battery 232…Charging port S10~S16, S20~S60...Step

Claims

1. a first optical communication device connected to a receiving coil unit attached to a subject; two or more second optical communication devices that are provided at a front position and a back position within a bore of a gantry of the magnetic resonance imaging apparatus, respectively, and that are capable of wireless optical communication with the first optical communication device; a processor that controls optical communication between the first optical communication device and the second optical communication device; The processor: before starting a main scan by the magnetic resonance imaging apparatus, optical communication is performed between the first optical communication device and the second optical communication device, and link-up check information indicating which of two or more second optical communication devices should be used is obtained by the optical communication; selecting the second optical communication device to be used for the main scan from two or more of the second optical communication devices based on the link-up check information; When the main scan is started, optical communication is performed between the first optical communication device and the selected second optical communication device, and a nuclear magnetic resonance signal received by the second optical communication device is acquired through the optical communication. Wireless optical communication system.

2. The link-up check information is an offset position of the first optical communication device relative to a reference position of the receiving coil unit, or a type or model number of the receiving coil unit.

10. The wireless optical communication system of claim 1.

3. the link-up check information is the reception intensity received by each of the two or more second optical communication devices, The processor: a pre-scan is performed using two or more of the second optical communication devices before the start of the main scan; In the pre-scan, the second optical communication device to be used in the main scan is selected based on the reception intensities received by the two or more second optical communication devices.

10. The wireless optical communication system of claim 1.

4. the receiving coil unit includes a memory that stores an offset position of the first optical communication device relative to a reference position of the receiving coil unit or a type or model number of the receiving coil unit; The processor reads the offset position or the type or model number of the receiving coil unit from the memory by the optical communication before the start of the main scan.

10. The wireless optical communication system of claim 1.

5. When the processor acquires the type or model number of the receiving coil unit, the processor acquires information indicating the offset position set according to the type or model number of the receiving coil unit or one of the second optical communication devices to be used for the main scan.

5. The wireless optical communication system according to claim 4.

6. the processor acquires position information of the first optical communication device on a top board of a bed on which the subject is placed, based on two or more reception signals received by the two or more second optical communication devices, respectively, through the optical communication before the start of the main scan.

6. The wireless optical communication system according to claim 4 or 5.

7. a third optical communication device capable of wireless optical communication with the first optical communication device of the receiving coil unit before a top plate of a bed on which the subject is placed starts to move; The processor executes optical communication between the first optical communication device and the third optical communication device before starting the main scan, and acquires an offset position of the first optical communication device with respect to a reference position of the receiving coil unit, or a type or model number of the receiving coil unit.

3. The wireless optical communication system according to claim 2.

8. the third optical communication device is provided on the ceiling above the bed; 8. The wireless optical communication system of claim 7.

9. The processor: acquiring information to be used for position control of a tabletop on which the subject is placed by optical communication before the start of the main scan; automatically or manually controlling the position of the tabletop to be fed into the bore based on the acquired information, and moving the receiving coil unit to an imaging area within the bore.

10. The wireless optical communication system of claim 1.

10. the processor controls the position of the tabletop based on the acquired position information and the offset position to move the reference position of the receiving coil unit to the center of the imaging area in the bore of the gantry, or outputs assist information for manually moving the tabletop, the assist information being for moving the reference position of the receiving coil unit to the center of the imaging area.

7. The wireless optical communication system of claim 6.

11. the processor acquires the link-up check information for each repetition period of the main scan or for each of a plurality of repetition periods of the main scan.

10. The wireless optical communication system of claim 1.

12. A wireless optical communication method comprising: a first optical communication device connected to a receiving coil unit attached to a subject; two or more second optical communication devices provided at front and rear positions within a bore of a gantry of a magnetic resonance imaging apparatus, the second optical communication devices being capable of wireless optical communication with the first optical communication device; and a processor that controls optical communication between the first optical communication device and the second optical communication devices, the processor executing the following steps: performing optical communication between the first optical communication device and the second optical communication device before starting a main scan by the magnetic resonance imaging apparatus, and obtaining link-up check information indicating which of two or more second optical communication devices should be used by the optical communication; selecting the second optical communication device to be used for the main scan from two or more of the second optical communication devices based on the link-up check information; When the main scan is started, optical communication is performed between the first optical communication device and the selected second optical communication device, and a nuclear magnetic resonance signal received by the second optical communication device is acquired through the optical communication; A wireless optical communication method comprising:

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