CN112327232B - Multi-core multichannel nuclear magnetic resonance radio frequency link real-time switching control device - Google Patents
Multi-core multichannel nuclear magnetic resonance radio frequency link real-time switching control device Download PDFInfo
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- CN112327232B CN112327232B CN202011188015.7A CN202011188015A CN112327232B CN 112327232 B CN112327232 B CN 112327232B CN 202011188015 A CN202011188015 A CN 202011188015A CN 112327232 B CN112327232 B CN 112327232B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
- G01R33/28—Details of apparatus provided for in groups G01R33/44 - G01R33/64
- G01R33/32—Excitation or detection systems, e.g. using radio frequency signals
- G01R33/36—Electrical details, e.g. matching or coupling of the coil to the receiver
- G01R33/3642—Mutual coupling or decoupling of multiple coils, e.g. decoupling of a receive coil from a transmission coil, or intentional coupling of RF coils, e.g. for RF magnetic field amplification
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B17/00—Monitoring; Testing
- H04B17/30—Monitoring; Testing of propagation channels
- H04B17/382—Monitoring; Testing of propagation channels for resource allocation, admission control or handover
Abstract
The invention discloses a multi-core multichannel nuclear magnetic resonance radio frequency link real-time switching control device, which comprises a photoelectric receiving module, a logic control module, a channel expansion and isolation module and a switch driving module, wherein the photoelectric receiving module is connected with the logic control module; the optical signal is adopted to transmit data, so that signal attenuation can be effectively reduced, and the anti-interference capability of the signal is improved; the logic control module and the switch driving module are physically isolated, so that the control module can be prevented from being interfered by a high-voltage driving signal, and the reliability of the system is improved.
Description
Technical Field
The invention relates to the technical field of nuclear magnetic resonance instruments, in particular to a real-time switching control device for a multi-core multi-channel nuclear magnetic resonance radio frequency link, which is suitable for a nuclear magnetic resonance imager or a nuclear magnetic resonance spectrometer and is used for realizing the state switching and control of the radio frequency link between multi-core multi-channel radio frequency coils.
Background
The nuclear magnetic resonance radio frequency coil is an important component for exciting and acquiring magnetic resonance signals, and the coil can be roughly divided into a receiving and transmitting integrated coil and a receiving and transmitting separated coil according to different working modes. In order to protect a preamplifier directly connected with the coil in the working mode, a high-power radio-frequency signal needs to be connected to a radio-frequency coil in a signal excitation stage, and the connection between the radio-frequency coil and the preamplifier is cut off; in the signal acquisition stage, a weak nuclear magnetic resonance signal needs to be connected to a preamplifier for amplification, and the connection between the coil and a radio frequency power amplifier is cut off, so that a Transmit-Receive switching signal T/R (Transmit-Receive) is needed to control the working state of the coil in real time. For the receiving and transmitting separated coil, the signal excitation and acquisition are respectively completed by different coils, but because the excitation coil and the acquisition coil have the same resonant frequency, if the two coils are simultaneously in a working state, the transmitting coil and the receiving coil have strong coupling, so that the performance of the coil is reduced, and even the preamplifier and the power amplifier are damaged. In order to avoid this, a detuning circuit needs to be designed on the coil to ensure that the transmitting coil and the receiving coil are not in an operating state at the same time, so a signal T/D (Tune-Tune) for controlling coil tuning and detuning states is needed to control the transceiving split coil to operate in a time-sharing manner.
With the development of nuclear magnetic resonance technology, multi-nuclear-element multi-channel parallel excitation and acquisition technology has been gradually applied to nuclear magnetic resonance instruments, and the technology needs to integrate radio frequency coils of various nuclear species together to realize the parallel excitation and acquisition of multi-nuclear-element magnetic resonance signals. However, spatial coupling between coils of different nuclear species also exists, which if not eliminated would greatly reduce the efficiency of the coils or even prevent resonance, so that T/D signals are also required between coils of multiple nuclear species to control the time-sharing operation of different coils. Meanwhile, a certain nuclide coil in the multi-nuclide coil can be independently used for exciting and collecting signals of corresponding nuclides, under the condition, other coils which do not work need to be detuned, and then the working state of the coils is switched according to the working mode of the coils, so that the multi-nuclide coil can be ensured to work in a single nuclide mode and a multi-nuclide mode flexibly, and the utilization rate of the coils is improved. In summary, the working mode of the multi-core multi-channel rf coil always requires one or more sets of signals (T/R or T/D) to switch and control in real time, so as to ensure that the coil is in the optimal working state.
The design scheme for realizing the real-time switching control device of the working mode of the multi-nuclide multi-channel radio frequency coil is only reported in documents at present, the radio frequency link switching device is designed only for a certain nuclide in the prior art, the real-time switching of the multi-nuclide multi-channel radio frequency link cannot be completed, meanwhile, the prior art adopts a mode of directly transmitting the electric signal from the control system for control, and the proposal has no problem when the signal transmission distance is short, however, when the distance between the control system and the coil is relatively long, the signal attenuation and external noise interference introduced by the internal resistance of the transmission line will greatly affect the quality of the control signal, resulting in the voltage drop and waveform distortion of the control signal, and the control reliability is reduced, or even the real-time switching of the radio frequency link cannot be completed, therefore, the design of the radio frequency link real-time switching control unit with strong anti-interference capability and high reliability is an important premise for realizing multi-core multi-channel parallel excitation and acquisition technology.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides the multi-core multichannel nuclear magnetic resonance radio frequency link real-time switching control device, which can realize the real-time switching of radio frequency link signals of various nuclides and ensure that the working state of a coil meets the design requirement.
The above object of the present invention is achieved by the following technical solutions:
a multi-core multi-channel nuclear magnetic resonance radio frequency link real-time switching control device comprises a photoelectric receiving module, a logic control module, a channel expansion and isolation module and a switch driving module,
a photoelectric receiving module for converting the RF link switching control optical signal sent by the control system into an RF link switching control electrical signal and outputting the RF link switching control electrical signal to the logic control module,
the logic control module is used for developing and sending the radio frequency link switching control electric signals to the corresponding channel expansion and isolation modules according to different nuclide types, and sending the expansion information of the radio frequency link switching control electric signals of which channels are needed by each nuclide to the corresponding channel expansion and isolation modules;
the channel expansion and isolation module is used for performing multi-channel expansion on the radio frequency link switching control electric signal output by the logic control module according to the expansion information and outputting the radio frequency link switching control electric signal to the corresponding switch driving module;
and the switch driving module is used for performing voltage conversion on the radio frequency link switching control electric signal.
A multi-core multi-channel nuclear magnetic resonance radio frequency link real-time switching control device, which also comprises a photoelectric emission module and a state indication module,
the logic control module also outputs a status indication signal to the status indication module and the optoelectronic transmission module,
a state indicating module for displaying state indicating signals, wherein the state indicating signals comprise the type of the radio frequency coil, the number of channels and the working state of the radio frequency coil,
and the photoelectric emission module is used for sending the state indication signal to the control system.
Each photoelectric receiving module correspondingly receives a radio frequency link switching control optical signal of a nuclide, and each channel extension and isolation module correspondingly receives extension information of a nuclide and a radio frequency link switching control electrical signal.
Compared with the prior art, the invention has the following advantages:
1. the multi-nuclear-element multi-channel radio frequency link switching control method can not only realize the real-time switching control of the multi-nuclear-element multi-channel radio frequency link, but also realize the real-time switching control of the multi-nuclear-element multi-channel radio frequency link of a single nuclear species or a combination of several nuclear species, and has strong flexibility;
2. the radio frequency link real-time switching control signal and the state indicating signal are transmitted by adopting optical signals, so that the signal attenuation can be effectively reduced, and the anti-interference capability of the signals is improved;
3. the logic control module and the switch driving module are physically isolated, so that the logic control module can be prevented from being interfered by a high-voltage driving signal, and the reliability of the system is improved.
Drawings
Fig. 1 is a schematic diagram of the principle of the present invention.
Detailed Description
The present invention will be described in further detail with reference to examples for the purpose of facilitating understanding and practice of the invention by those of ordinary skill in the art, and it is to be understood that the present invention has been described in the illustrative embodiments and is not to be construed as limited thereto.
Example 1
As shown in FIG. 1, a multi-core multi-channel nuclear magnetic resonance radio frequency link real-time switching control device comprises a photoelectric receiving module 1, a logic control module 2, a channel expansion and isolation module 3, a switch driving module 4, a photoelectric emitting module 5 and a state indicating module 6,
the photoelectric receiving module 1 is used for converting the radio frequency link switching control optical signal sent by the control system into a radio frequency link switching control electrical signal and outputting the converted radio frequency link switching control electrical signal to the logic control module 2, the radio frequency link switching control optical signal sent by the control system mainly comprises a radio frequency link receiving/sending switching optical signal T/R and/or a radio frequency link tuning/detuning switching optical signal T/D, a core device of the photoelectric receiving module is AFBR-2529Z,
the logic control module 2 is used for classifying and expanding the radio frequency link switching control electric signals output by the photoelectric receiving module 1, wherein the classification refers to developing and sending the radio frequency link switching control electric signals to the corresponding channel expansion and isolation module 3 according to different nuclide types, and then outputting the expansion information of the radio frequency link switching control electric signals corresponding to each nuclide to the channel expansion and isolation module 3 according to design requirements, wherein the design requirements refer to the number of the nuclides to be provided with the radio frequency link switching control electric signals and the number of the radio frequency link switching control electric signals of each nuclide to be required; the logic control module 2 also outputs a state indicating signal to the state indicating module 6 and the photoelectric transmitting module 5 for displaying the working state of the device; the core device of the logic control module is EP4CE6E22,
the channel expansion and isolation module 3 is used for performing multi-channel expansion on the radio frequency link switching control electric signal output by the logic control module 2 according to the expansion information, isolating the radio frequency link switching control electric signal output by the logic control module 2 from the switch driving module 4, outputting the radio frequency link switching control electric signal processed by the channel expansion and isolation module 3 to the switch driving module 4, wherein the core device of the channel expansion and isolation module 3 is MC74HC245ADWG,
a switch driving module 4 for converting the radio frequency link switching control electrical signal into a voltage signal meeting the requirement and providing sufficient driving voltage and current for switching the working state of the nuclide radio frequency coil, the core devices of the switch driving module are CPH3351 and NTR5198,
a photoelectric emission module 5 for converting the status indication signal of the electrical signal output by the logic control module 2 into a status indication optical signal and sending the status indication optical signal to the control system, wherein the core device of the photoelectric emission module is HFBR1521,
and the state indicating module 6 is used for displaying a state indicating signal of the current device, which is output by the logic control module 2, wherein the state indicating signal comprises the type, the number of channels, the working state and the like of a nuclide radio frequency coil, and a core device of the state indicating module is L-53 GD.
The photoelectric receiving module 1 is connected with the logic control module 2, the channel expansion and isolation module 3 is connected with the switch driving module 4, the logic control module 2 is also respectively connected with the channel expansion and isolation module 3, the photoelectric emitting module 5 and the state indicating module 6,
at least one photoelectric receiving module 1 is provided, the number of the photoelectric receiving modules depends on the number of nuclides and corresponds to one,
the number of the switch driving modules 4 is determined by the number of the nuclides and the number of channels of the radio frequency coil of each nuclide, and the radio frequency link receiving/transmitting switching signal T/R or the radio frequency link tuning/detuning switching signal T/D.
The principle schematic diagram of the invention is shown in fig. 1, radio frequency link switching control optical signals of a plurality of nuclides or a single nuclide (including radio frequency link receiving/transmitting switching optical signals T/R and radio frequency link tuning/detuning switching optical signals T/D) are transmitted to a photoelectric receiving module 1 through an optical fiber, then the photoelectric receiving module 1 converts the radio frequency link switching control optical signals into radio frequency link switching control electrical signals and outputs the radio frequency link switching control electrical signals to a logic control module 2, the logic control module 2 is implemented by a Programmable gate array (FPGA) chip and is responsible for classifying the radio frequency link switching control electrical signals, the radio frequency link switching control electrical signals of each nuclide are respectively output to a corresponding channel expansion and isolation module 3, and the logic control module 2 also outputs the state indication signals of the current device and outputs the state indication signals to a state indication module 6 for display, the state indicating signal comprises the type, the channel number, the working state and the like of the nuclide radio frequency coil, the state indicating module 6 is composed of a photodiode or a liquid crystal display screen, the logic control module 2 is also responsible for outputting the state indicating signal to the photoelectric emission module 5, and the state indicating signal is converted into a state indicating optical signal by the photoelectric emission module 5 and then is transmitted to the control system. The channel isolation and expansion module 3 is responsible for performing multi-channel expansion on the radio frequency link switching control electric signals output by the logic control module 2, the number of the expanded radio frequency link switching control electric signals is the same as that of nuclide radio frequency coils to be controlled, the purpose of isolating the radio frequency link switching control electric signals from high-voltage driving signals is achieved, the expanded radio frequency link switching control electric signals are output to the switch driving module, the switch driving module converts the radio frequency link switching control electric signals into voltage signals meeting requirements, and sufficient driving voltage and current are provided for switching the working state of the radio frequency coils.
In order to realize the receiving and processing of multi-core multi-channel radio frequency link control signals, the invention provides independent photoelectric receiving modules for each nuclide, namely a photoelectric receiving module 1 to a photoelectric receiving module n, wherein n is the number of nuclides to be observed, and simultaneously provides an independent switch driving module for each nuclide radio frequency coil of each nuclide for each nuclide, namely a switch driving module 1 to a switch driving module m, wherein m is the number of channels of each nuclide radio frequency coil. The design can not only realize the real-time switching and control of the multi-core multi-channel radio frequency chain, but also realize the real-time switching control of the multi-channel radio frequency chain of single nuclide or combination of several nuclides, and has strong flexibility and expansibility. Meanwhile, the radio frequency link switching control optical signal output by the control system and the state indication optical signal output by the device are both optical signals, can effectively solve the problem of signal attenuation distortion caused by too long distance during electric signal transmission, has stronger reliability and anti-jamming capability, particularly in a magnetic resonance imaging instrument, the distance between the control system and a nuclide radio frequency coil is about more than ten meters or even longer, in this case, the use of electrical signal transmission may cause a large voltage drop in the control voltage to the rf coil, which may result in failure to switch the state of the rf coil, in addition, the status indication signal transmitted back to the control system by the device can generate signal attenuation and distortion if the signal is transmitted by electricity, thereby causing information loss and error code generation, therefore, the invention adopts the optical signal to transmit the radio frequency link control signal and the state information, and can overcome the signal attenuation and distortion caused by too long distance during the transmission of the electric signal.
The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the invention as defined in the appended claims.
Claims (3)
1. A multi-core multi-channel nuclear magnetic resonance radio frequency link real-time switching control device comprises a photoelectric receiving module (1), and is characterized by also comprising a logic control module (2), a channel expansion and isolation module (3) and a switch driving module (4),
a photoelectric receiving module (1) for converting the radio frequency link switching control optical signal sent by the control system into a radio frequency link switching control electrical signal and outputting the signal to a logic control module (2),
the logic control module (2) is used for developing and sending the radio frequency link switching control electric signals to the corresponding channel expansion and isolation module (3) according to different nuclide types, and sending the expansion information of the radio frequency link switching control electric signals of which channels are needed by each nuclide to the corresponding channel expansion and isolation module (3);
the channel expansion and isolation module (3) is used for performing multi-channel expansion on the radio frequency link switching control electric signal output by the logic control module (2) according to the expansion information and outputting the multi-channel expansion to the corresponding switch driving module (4);
and the switch driving module (4) is used for converting the voltage of the radio frequency link switching control electric signal.
2. The real-time switching control device of multi-core multi-channel nuclear magnetic resonance radio frequency link according to claim 1, further comprising a photoelectric emission module (5) and a status indication module (6),
the logic control module (2) also outputs a state indicating signal to the state indicating module (6) and the photoelectric emission module (5),
a status indication module (6) for displaying status indication signals, the status indication signals including the type of the radio frequency coil, the number of channels and the working status of the radio frequency coil,
and the photoelectric emission module (5) is used for sending the state indication signal to the control system.
3. The apparatus of claim 1, wherein each of the plurality of photoelectric receiving modules receives a radio frequency link switching control optical signal of a nuclide, and each of the plurality of channel extension and isolation modules receives extension information of a nuclide and a radio frequency link switching control electrical signal.
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| CN114325522B (en) * | 2021-12-30 | 2023-09-05 | 武汉联影生命科学仪器有限公司 | Magnetic resonance circuit and magnetic resonance system |
| CN116520223B (en) * | 2023-07-03 | 2023-08-25 | 北京化工大学 | Radio frequency transceiver of high-field spectrometer |
| CN117075011B (en) * | 2023-10-11 | 2024-01-02 | 安徽福晴医疗装备有限公司 | Self-adaptive radio frequency switching system and method for magnetic resonance multi-core imaging |
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