CN113552518A - An Active Radio Frequency Shielding System for Magnetic Resonance Imaging Systems - Google Patents

Abstract

The invention discloses an active radio frequency shielding system of a magnetic resonance imaging system. The coil, the second receiving board is connected with the receiving coil, the transmitting board is connected with the transmitting coil, the receiving coil receives the signal of the transmitting coil and the interference noise, and also includes a synthesizer. The spectrometer outputs the signal to the transmitter board, the transmitter board transmits the signal through the transmitter coil, the detection coil of the first receiver board receives the interference signal, the receiver coil of the second receiver board receives the signal of the transmitter coil and the interference signal, the first receiver board and the first receiver board receive the interference signal. The signal received by the second receiving board is sent to the synthesizer. The synthesizer reverses, modulates the amplitude and modulates the frequency of the signal of the first receiving board, and cancels the interference noise signal of the first receiving board and the interference noise signal of the second receiving board. Only Output The clean output signal is sent to the spectrometer.

Description

Active radio frequency shielding system of magnetic resonance imaging system

Technical Field

The invention belongs to the technical field of electronics, and particularly relates to an active radio frequency shielding system of a magnetic resonance imaging system.

Background

The magnetic resonance imaging system obtains weak electromagnetic signals by utilizing a magnetic resonance phenomenon, and obtains images after multistage amplification. Generally, a shielding room is required to be built for shielding external interference to influence magnetic resonance signals, but the shielding room is complex in structure, high in cost and long in period, so that the magnetic resonance imaging system cannot be applied to various flexible environments, and therefore the active radio frequency shielding system of the magnetic resonance imaging system for overcoming the defects is very important.

Disclosure of Invention

In order to solve the technical problems, the invention provides an active radio frequency shielding system of a magnetic resonance imaging system, which comprises a spectrometer, a first receiving plate and a second receiving plate, wherein the output end of the spectrometer is connected with a transmitting plate; the first receiving plate and the second receiving plate are connected with the input end of the synthesizer, and the output end of the synthesizer is connected with the input end of the spectrometer. The invention realizes the reverse amplitude modulation and frequency modulation of the signal output by the first receiving board in the synthesizer.

The output end of the first receiving plate is connected with the input end of the synthesizer through the front discharging circuit. The output end of the second receiving plate is connected with the input end of the synthesizer through the front discharging circuit. The output end of the synthesizer is connected with the input end of the spectrometer through a power amplifier circuit. The output end of the spectrometer is connected with the transmitting plate through the radio frequency power amplifier circuit.

The spectrometer also comprises a computer, wherein the output end of the spectrometer is connected with the computer.

The transmitting plate comprises an eighth capacitor, a tenth inductor, a COIL COIL2, a first diode, an eleventh inductor and an eighth inductor which are connected in series, the tenth inductor is connected with the tenth capacitor in parallel, the eleventh inductor is connected with the eleventh capacitor in parallel, the transmitting plate further comprises a ninth inductor and a ninth capacitor which are connected in series, the connection position of the eighth capacitor and the eighth inductor is grounded, the connection position of the ninth inductor and the ninth capacitor outputs a signal TX to a spectrometer, the transmitting plate further comprises a twelfth capacitor, the first diode and the COIL COIL2 are connected in series and then connected with the twelfth capacitor in parallel, and the COIL COIL2 is a transmitting COIL.

The first receiving board and the second receiving board have the same circuit structure and respectively comprise a second inductor, a second capacitor, a first capacitor, a third capacitor and a fifth capacitor which are connected in series to form a loop, the first capacitor is connected with a COIL COIL1 in parallel, the first receiving board further comprises a fourth capacitor and a first inductor which are connected in series, the fourth capacitor and the first inductor are connected in series and then connected with the second inductor and the fifth capacitor which are connected in series in parallel, a signal RX is output to a synthesizer at the connection position of the fourth capacitor and the first inductor, and the COIL COIL1 is a detection COIL or a receiving COIL. The synthesizer comprises a third inductor, a fourth inductor, a fifth inductor, a sixth inductor, a fourth resistor, a connector J2, a connector J3, a seventh inductor and a connector J1 which are sequentially connected in series, wherein two sides of the third inductor are respectively connected with the first ends of a sixth capacitor and a seventh capacitor, the second ends of the sixth capacitor and the seventh capacitor are grounded, two sides of the fourth inductor are respectively connected with the first ends of an eighth capacitor and a ninth capacitor, the second ends of the eighth capacitor and the ninth capacitor are grounded, two sides of the sixth inductor are respectively connected with the first ends of a tenth capacitor and an eleventh capacitor, the second ends of the tenth capacitor and the eleventh capacitor are grounded, two sides of the fourth resistor are respectively connected with the first ends of the second resistor and the third resistor, the second ends of the second resistor and the third resistor are grounded, the joint of the connector J2 and the connector J3 is grounded, two sides of the seventh inductor are respectively connected with the first ends of a twelfth capacitor and a thirteenth capacitor, the second ends of the twelfth capacitor and the thirteenth capacitor are grounded, the connector J1 is grounded, the connector J3 is connected with the second receiving board, the connector J2 is connected with the first receiving board, and the connector J1 is connected with the spectrometer.

The working principle of the invention is as follows: the spectrometer outputs signals to the transmitting plate, the transmitting plate transmits the signals through the transmitting coil, the detecting coil of the first receiving plate receives interference signals, the receiving coil of the second receiving plate receives the signals of the transmitting coil and the interference signals, the signals received by the first receiving plate and the second receiving plate are sent to the synthesizer, the synthesizer conducts inversion, amplitude modulation and frequency modulation on the signals of the first receiving plate, interference noise signals of the first receiving plate and interference noise signals of the second receiving plate are offset, and only pure output signals are output and sent to the spectrometer.

Compared with the prior art, the invention has the advantages that: the active radio frequency shielding system has a simple structure, and can liberate the magnetic resonance system from a large and complex shielding room, so that the magnetic resonance system can be applied to the following fields: in mobile nuclear magnetic, bedside nuclear magnetic, vehicle nuclear magnetic and other scenes, the configuration of a magnetic resonance system can be simplified.

Drawings

FIG. 1 is a block diagram of the present invention;

FIG. 2 is a circuit diagram of a transmitter board of the present invention;

FIG. 3 is a circuit configuration diagram of a first receiving board and a second receiving board according to the present invention;

FIG. 4 is a circuit block diagram of the synthesizer of the present invention;

reference numerals: 1-spectrometer; 2-a transmitting plate; 3-a transmitting coil; 4-a receiving coil; 5-a detection coil; 6-a first receiving plate; 7-a second receiving plate; 8-a synthesizer.

Detailed Description

In order that those skilled in the art will better understand the invention and thus more clearly define the scope of the invention as claimed, it is described in detail below with respect to certain specific embodiments thereof. It should be noted that the following is only a few embodiments of the present invention, and the specific direct description of the related structures is only for the convenience of understanding the present invention, and the specific features do not of course directly limit the scope of the present invention.

Referring to the drawings, the invention adopts the following technical scheme that the active radio frequency shielding system of the magnetic resonance imaging system comprises a spectrometer, wherein the output end of the spectrometer is connected with a transmitting plate, the active radio frequency shielding system further comprises a first receiving plate and a second receiving plate, the first receiving plate is connected with a detecting coil, the second receiving plate is connected with a receiving coil, the transmitting plate is connected with a transmitting coil, and the receiving coil receives signals and interference noise of the transmitting coil; the first receiving plate and the second receiving plate are connected with the input end of the synthesizer, and the output end of the synthesizer is connected with the input end of the spectrometer. The invention realizes the reverse amplitude modulation and frequency modulation of the signal output by the first receiving board in the synthesizer.

The output end of the first receiving plate is connected with the input end of the synthesizer through the front discharging circuit. The output end of the second receiving plate is connected with the input end of the synthesizer through the front discharging circuit. The output end of the synthesizer is connected with the input end of the spectrometer through a power amplifier circuit. The output end of the spectrometer is connected with the transmitting plate through the radio frequency power amplifier circuit.

The spectrometer also comprises a computer, wherein the output end of the spectrometer is connected with the computer.

The circuit structure of the transmitting plate is as shown in fig. 2, and includes an eighth capacitor, a tenth inductor, a COIL2, a first diode, an eleventh inductor and an eighth inductor, the tenth inductor is connected in parallel with the tenth capacitor, the eleventh inductor is connected in parallel with the eleventh capacitor, and further includes a ninth inductor and a ninth capacitor connected in series, the junction of the eighth capacitor and the eighth inductor is grounded, the junction of the ninth inductor and the ninth capacitor outputs a signal TX to a spectrometer, and further includes a twelfth capacitor, the first diode and the COIL2 are connected in series and then connected in parallel with the twelfth capacitor, and the COIL2 is a transmitting COIL.

The circuit structures of the first receiving board and the second receiving board are the same as each other, as shown in fig. 3, the first receiving board and the second receiving board include a second inductor, a second capacitor, a first capacitor, a third capacitor and a fifth capacitor which are connected in series to form a loop, the first capacitor is connected in parallel with a COIL1, the first receiving board further includes a fourth capacitor and a first inductor which are connected in series, the fourth capacitor and the first inductor are connected in parallel with the second inductor and the fifth capacitor which are connected in series after being connected in series, a connection position of the fourth capacitor and the first inductor outputs a signal RX to a synthesizer, and the COIL1 is a detection COIL or a receiving COIL.

The circuit structure of the synthesizer is shown in fig. 4, and includes a third inductor, a fourth inductor, a fifth inductor, a sixth inductor, a fourth resistor, a connector J2, a connector J3, a seventh inductor, and a connector J1, which are connected in series in sequence, wherein two sides of the third inductor are respectively connected to first ends of a sixth capacitor and a seventh capacitor, second ends of the sixth capacitor and the seventh capacitor are grounded, two sides of the fourth inductor are respectively connected to first ends of an eighth capacitor and a ninth capacitor, second ends of the eighth capacitor and the ninth capacitor are grounded, two sides of the sixth inductor are respectively connected to first ends of a tenth capacitor and an eleventh capacitor, second ends of the tenth capacitor and the eleventh capacitor are grounded, two sides of the fourth resistor are respectively connected to first ends of the second resistor and the third resistor, second ends of the second resistor and the third resistor are grounded, a connection point of the connector J2 and the connector J3 is grounded, two sides of the seventh inductor are respectively connected to first ends of a twelfth capacitor and a thirteenth capacitor, the second ends of the twelfth capacitor and the thirteenth capacitor are grounded, the connector J1 is grounded, the connector J3 is connected with the second receiving board, the connector J2 is connected with the first receiving board, and the connector J1 is connected with the spectrometer.

The working principle of the invention is as follows: the spectrometer outputs signals to the transmitting plate, the transmitting plate transmits the signals through the transmitting coil, the detecting coil of the first receiving plate receives interference signals, the receiving coil of the second receiving plate receives the signals of the transmitting coil and the interference signals, the signals received by the first receiving plate and the second receiving plate are sent to the synthesizer, the synthesizer conducts inversion, amplitude modulation and frequency modulation on the signals of the first receiving plate, interference noise signals of the first receiving plate and interference noise signals of the second receiving plate are offset, and only pure output signals are output and sent to the spectrometer.

Compared with the prior art, the invention has the advantages that: the active radio frequency shielding system has a simple structure, and can liberate the magnetic resonance system from a large and complex shielding room, so that the magnetic resonance system can be applied to the following fields: in mobile nuclear magnetic, bedside nuclear magnetic, vehicle nuclear magnetic and other scenes, the configuration of a magnetic resonance system can be simplified.

The above description is not intended to limit the present invention, and the present invention is not limited to the above examples, and variations, modifications, additions and substitutions which may be made by those skilled in the art within the spirit of the present invention are within the scope of the present invention.

Claims (9)

1. an active radio frequency shielding system of a magnetic resonance imaging system, comprising a spectrometer (1), and the output end of the spectrometer (1) is connected to a transmitting plate (2), characterized in that: also comprising a first receiving plate (6 ) and a second receiving board (7), a detection coil (5) is connected to the first receiving board (6), a receiving coil (4) is connected to the second receiving board (7), and the transmitting board (2) is connected with a transmitting coil (3), and the receiving coil (4) receives the signal of the transmitting coil (3) and the interference noise; It also includes a synthesizer (8), the first receiving board (6) and the second receiving board (7) are connected to the input end of the synthesizer (8), and the output end of the synthesizer (8) is connected to the spectrometer (1) ) input terminal. 2 . The active radio frequency shielding system of the magnetic resonance imaging system according to claim 1 , wherein the output end of the first receiving board ( 6 ) is connected to the input end of the combiner ( 8 ) through a preamplifier circuit. 3 . 3 . The active radio frequency shielding system of the magnetic resonance imaging system according to claim 1 , wherein the output end of the second receiving board ( 7 ) is connected to the input end of the combiner ( 8 ) through a preamplifier circuit. 4 . 4 . The active radio frequency shielding system of the magnetic resonance imaging system according to claim 1 , wherein the output end of the combiner ( 8 ) is connected to the input end of the spectrometer ( 1 ) through a power amplifier circuit. 5 . 5 . The active radio frequency shielding system of the magnetic resonance imaging system according to claim 1 , wherein the output end of the spectrometer ( 1 ) is connected to the transmitting board ( 2 ) through a radio frequency power amplifier circuit. 6 . 6 . The active radio frequency shielding system of the magnetic resonance imaging system according to claim 1 , further comprising a computer, and the output end of the spectrometer ( 1 ) is connected to the computer. 7 . 7 . The active radio frequency shielding system of the magnetic resonance imaging system according to claim 1 , wherein the transmitting plate ( 2 ) comprises an eighth capacitor, a tenth inductor, a coil COIL2 , a first diode, The eleventh inductor and the eighth inductor, the tenth inductor is connected in parallel with the tenth capacitor, the eleventh inductor is connected in parallel with the eleventh capacitor, and also includes the ninth inductor and the ninth capacitor connected in series, and the connection between the eighth capacitor and the eighth inductor is grounded, The connection between the ninth inductor and the ninth capacitor outputs a signal TX to the spectrometer (1), and also includes a twelfth capacitor. The first diode is connected in series with the coil COIL2 and is connected in parallel with the twelfth capacitor, and the coil COIL2 is a transmitting coil. 8 . The active radio frequency shielding system of the magnetic resonance imaging system according to claim 1 , wherein the circuit structures of the first receiving board ( 6 ) and the second receiving board ( 7 ) are the same, and both comprise a series circuit to form a loop. 9 . The second inductor, the second capacitor, the first capacitor, the third capacitor and the fifth capacitor, the first capacitor is connected with the coil COIL1 in parallel, and also includes a fourth capacitor and a first inductor connected in series, the fourth capacitor and the first The inductance is connected in series with the second inductance and the fifth capacitor in parallel. The connection between the fourth capacitor and the first inductance outputs a signal RX to the combiner (8), wherein the coil COIL1 is a detection coil or a receiving coil. 9. The active radio frequency shielding system of a magnetic resonance imaging system according to claim 1, wherein the combiner (8) comprises a third inductor, a fourth inductor, a fifth inductor, a sixth inductor, The fourth resistor, the connector J2, the connector J3, the seventh inductor, and the connector J1, the two sides of the third inductor are respectively connected to the sixth capacitor, the first end of the seventh capacitor, and the second end of the sixth capacitor and the seventh capacitor Grounding, the two sides of the fourth inductor are respectively connected to the first ends of the eighth capacitor and the ninth capacitor, the second ends of the eighth capacitor and the ninth capacitor are grounded, and the two sides of the sixth inductor are respectively connected to the tenth capacitor and the eleventh capacitor. The first end of the tenth capacitor and the second end of the eleventh capacitor are grounded, the two sides of the fourth resistor are respectively connected to the first end of the second resistor and the third resistor, and the second end of the second resistor and the third resistor Ground, the connection between the connector J2 and the connector J3 is grounded, the two sides of the seventh inductor are respectively connected to the first ends of the twelfth capacitor and the thirteenth capacitor, and the second ends of the twelfth capacitor and the thirteenth capacitor are grounded , the connector J1 is grounded, the connector J3 is connected to the second receiving board (7), the connector J2 is connected to the first receiving board (6), and the connector J1 is connected to the spectrometer (1).

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