CN114910850B

CN114910850B - Image enhancement super-structure surface device of dual-core MRI

Info

Publication number: CN114910850B
Application number: CN202110183943.2A
Authority: CN
Inventors: 赵乾; 池中海; 郑卓肇; 孟永钢; 周济
Original assignee: Tsinghua University; Beijing Tsinghua Changgeng Hospital
Current assignee: Tsinghua University; Beijing Tsinghua Changgeng Hospital
Priority date: 2021-02-10
Filing date: 2021-02-10
Publication date: 2024-04-23
Anticipated expiration: 2041-02-10
Also published as: CN114910850A

Abstract

The application relates to an image enhancement super-structured surface device of dual-core MRI, in particular to a dual-core magnetic field enhancement device and a magnetic resonance system, wherein the dual-core magnetic field enhancement device comprises a first cylindrical magnetic field enhancer and a second cylindrical magnetic field enhancer. The first cylindrical magnetic field enhancer encloses a first receiving space. The first cylindrical magnetic field enhancer is used for enhancing the nuclear magnetic signal of hydrogen nuclei of the detection part. The second cylindrical magnetic field enhancer is arranged in the first accommodating space and used for enhancing the nuclear magnetic signal of the non-hydrogen sub-nucleus of the detection part. The second cylindrical magnetic field enhancer surrounds and forms a second accommodating space for accommodating the detection part. The dual-nuclear magnetic field enhancement device realizes simultaneous enhancement of two signal fields of dual-nuclear MRI of hydrogen proton nuclei and non-hydrogen proton nuclei. Compared with the prior art, the dual-core magnetic field enhancement device can have higher magnetic field enhancement effect. The dual nuclear magnetic field enhancement device can assist the MRI apparatus to obtain higher quality images when applied to the imaging of the MRI apparatus.

Description

Image enhancement super-structure surface device of dual-core MRI

Technical Field

The application relates to the technical field of magnetic resonance imaging, in particular to a dual-nuclear magnetic field enhancement device and a magnetic resonance system.

Background

The magnetic resonance imaging (Magnetic Resonance Imaging, MRI) is a non-invasive detection method, and is an important basic diagnostic technique in the fields of medicine, biology and neuroscience. The signal intensity transmitted by the conventional MRI apparatus is mainly from hydrogen protons ¹ H. Of all nuclei having nuclear magnetic signals, hydrogen protons ¹ H are the highest in the human body, and the gyromagnetic ratio of hydrogen protons ¹ H is also the highest, with the strongest nuclear magnetic resonance signal. However, MRI based on hydrogen protons ¹ H contains less biological information such as metabolism, ion exchange, etc., while non-proton nuclei such as ²³Na、³¹P、¹⁹ F can provide rich biological information. Therefore, imaging based on ²³Na、³¹P、¹⁹ F and other non-proton nuclei is of great research interest in medical and life science research.

When MRI of ²³Na、³¹P、¹⁹ F and other non-proton nuclei is carried out, the signal to noise ratio of the non-proton nucleus image is improved, and the method has important significance. The signal-to-noise ratio is mainly determined by the static magnetic field strength, but an increase in the static magnetic field strength brings about three problems: 1) The non-uniformity of the Radio Frequency (RF) field is increased, and the tuning difficulty is increased; 2) The heat production of human tissues is increased, so that potential safety hazards are brought, and adverse reactions such as dizziness, vomiting and the like are easy to occur for patients: 3) The acquisition cost is greatly increased, which is a burden for most small-scale hospitals. Therefore, how to use a static magnetic field strength as small as possible while achieving high imaging quality becomes a critical issue in MRI technology.

The advent of super-structured materials provides a novel and more efficient method for improving MRI imaging quality and efficiency. Super-structured materials have many special properties that natural materials do not possess. The control of the electromagnetic wave propagation path and the electromagnetic field intensity distribution can be realized through the interaction between electromagnetic waves and metal or dielectric elements of the super-structural material and the coupling effect between the elements. The specific working principle is that electromagnetic resonance in a structure formed by the super-structure material is utilized to realize the adjustment of electromagnetic parameters such as anisotropy, gradient distribution and the like. In addition, resonance enhancement of different frequency points can be realized through the design of parameters such as geometric dimension, shape, dielectric constant and the like of the super-structure material.

However, the conventional magnetic field enhancement devices are designed for single-core MRI such as hydrogen nuclei ¹ H, and have no dual-core structure for aprotic and proton nuclei, so that rich biological information such as metabolism and ion exchange cannot be obtained.

Disclosure of Invention

In view of the above, it is necessary to provide a dual-core magnetic field enhancement device and a magnetic resonance system.

The application provides a dual-core magnetic field enhancement device. The dual nuclear magnetic field enhancement device includes a first cylindrical magnetic field enhancer and a second cylindrical magnetic field enhancer. The first cylindrical magnetic field enhancer encloses a first receiving space. The first cylindrical magnetic field enhancer is used for enhancing the nuclear magnetic signal of hydrogen nuclei of the detection part. The second cylindrical magnetic field enhancer is arranged in the first accommodating space and used for enhancing the nuclear magnetic signal of the non-hydrogen sub-nucleus of the detection part. The second cylindrical magnetic field enhancer surrounds and forms a second accommodating space for accommodating the detection part.

According to the dual-core magnetic field enhancement device and the magnetic resonance system, the first cylindrical magnetic field enhancer and the second cylindrical magnetic field enhancer are used for detecting different target cores at the same position, and MRI imaging information corresponding to the different target cores at the detection position can be displayed. The second cylindrical magnetic field enhancer is disposed within the first accommodation space. The second cylindrical magnetic field enhancer is arranged inside the binuclear magnetic field enhancing device. The first cylindrical magnetic field enhancer is arranged on the outer side of the binuclear magnetic field enhancing device. The second cylindrical magnetic field enhancer is nested with the first cylindrical magnetic field enhancer. The binuclear magnetic field enhancement device can enhance the nuclear magnetic signal of hydrogen nuclei and the nuclear magnetic signal of non-hydrogen nuclei in the detection part. The dual-nuclear magnetic field enhancement device realizes simultaneous enhancement of two signal fields of dual-nuclear MRI of hydrogen proton nuclei and non-hydrogen proton nuclei. Compared with the prior art, the dual-core magnetic field enhancement device can have higher magnetic field enhancement effect. The dual nuclear magnetic field enhancement device can assist the MRI apparatus to obtain higher quality images when applied to the imaging of the MRI apparatus.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments or the conventional techniques of the present application, the drawings required for the descriptions of the embodiments or the conventional techniques will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to the drawings without inventive effort for those skilled in the art.

FIG. 1 is a schematic diagram of a first cylindrical magnetic field enhancer and a second cylindrical magnetic field enhancer in a dual nuclear magnetic field enhancer device according to the present application;

FIG. 2 is a schematic diagram of the overall structure of the dual-core magnetic field enhancement device provided by the application;

FIG. 3 is a schematic view of a first cylindrical stent according to the present application;

fig. 4 is a schematic structural view of a second cylindrical support provided by the present application;

FIG. 5 is a schematic diagram illustrating the connection between the first resonant control circuit and the first magnetic field enhancement device according to the present application;

FIG. 6 is a schematic diagram illustrating the connection between a second resonant control circuit and a second magnetic field enhancement assembly according to the present application;

FIG. 7 is a side view of a second magnetic field enhancement assembly in accordance with one embodiment of the present application;

FIG. 8 is a top view of the second magnetic field enhancement assembly of FIG. 7;

FIG. 9 is a side view of a second magnetic field enhancement assembly provided in accordance with one embodiment of the present application;

FIG. 10 is a side view of a second magnetic field enhancement assembly provided in accordance with one embodiment of the present application;

FIG. 11 is a side view of a second magnetic field enhancement assembly provided in accordance with one embodiment of the present application;

FIG. 12 is a side view of a second magnetic field enhancement assembly provided in accordance with one embodiment of the present application;

FIG. 13 is a perspective view of a second magnetic field enhancement assembly provided in accordance with one embodiment of the present application;

FIG. 14 is a top view of a second magnetic field enhancement assembly according to an embodiment of the present application;

FIG. 15 is a bottom view of a second magnetic field enhancement assembly according to an embodiment of the present application;

FIG. 16 is a side view of a second magnetic field enhancement assembly provided in accordance with another embodiment of the present application;

FIG. 17 is a top view of a second magnetic field enhancement assembly according to an embodiment of the present application;

FIG. 18 is a bottom view of a second magnetic field enhancement assembly according to an embodiment of the present application;

FIG. 19 is a schematic diagram of a front projection of a first electrode layer and a second electrode layer on a first dielectric layer according to an embodiment of the present application;

FIG. 20 is a schematic diagram of a front projection shape of a first electrode layer and a second electrode layer on a first dielectric layer according to another embodiment of the present application;

FIG. 21 is a block diagram of a second magnetic field enhancement assembly according to an embodiment of the present application;

FIG. 22 is a frequency contrast diagram of a second magnetic field enhancement assembly according to an embodiment of the present application during a radio frequency transmit phase and a radio frequency receive phase;

FIG. 23 is a graph showing a comparison of the effects of a second magnetic field enhancement assembly provided by one embodiment of the present application;

FIG. 24 is a block diagram of a second magnetic field enhancement assembly according to another embodiment of the present application;

FIG. 25 is a block diagram of a second magnetic field enhancement assembly according to another embodiment of the present application;

FIG. 26 is a block diagram of a second magnetic field enhancement assembly according to another embodiment of the present application;

FIG. 27 is a block diagram of a second magnetic field enhancement assembly according to another embodiment of the present application;

FIG. 28 is a frequency contrast diagram of a second magnetic field enhancement assembly according to an embodiment of the present application during a radio frequency transmit phase and a radio frequency receive phase;

FIG. 29 is a block diagram of a second magnetic field enhancement assembly according to another embodiment of the present application;

FIG. 30 is a block diagram of a second magnetic field enhancement assembly according to another embodiment of the present application;

FIG. 31 is a block diagram of a second magnetic field enhancement assembly according to another embodiment of the present application;

FIG. 32 is a frequency contrast diagram of a second magnetic field enhancement assembly according to an embodiment of the present application during a radio frequency transmit phase and a radio frequency receive phase;

FIG. 33 is a block diagram of a second magnetic field enhancement assembly according to another embodiment of the present application;

FIG. 34 is a block diagram of a second magnetic field enhancement assembly according to another embodiment of the present application;

FIG. 35 is a side view of a first magnetic field enhancement assembly provided in one embodiment of the present application;

FIG. 36 is a top view of the embodiment of FIG. 35 in accordance with the present application;

FIG. 37 is a side view of a first magnetic field enhancement assembly in accordance with one embodiment of the present application;

FIG. 38 is a schematic view of the first magnetic field enhancement assembly of the embodiment of FIG. 37 in accordance with the present application;

FIG. 39 is a top view of a first magnetic field enhancement assembly according to an embodiment of the present application;

FIG. 40 is a bottom view of a first magnetic field enhancement assembly according to an embodiment of the present application;

FIG. 41 is a side view of a first magnetic field enhancement assembly in accordance with one embodiment of the present application;

FIG. 42 is a side view of a first magnetic field enhancement assembly in accordance with one embodiment of the present application;

FIG. 43 is a side view of a first magnetic field enhancement assembly in accordance with one embodiment of the present application;

FIG. 44 is a top view of a second via in one embodiment provided by the present application;

FIG. 45 is a side view of a first magnetic field enhancement assembly in accordance with one embodiment of the present application;

FIG. 46 is a side view of a first magnetic field enhancement assembly in accordance with one embodiment of the present application;

FIG. 47 is a side view of a first magnetic field enhancement assembly in accordance with one embodiment of the present application;

FIG. 48 is a schematic view of an exploded view of the first magnetic field enhancement assembly of the embodiment of FIG. 47 in accordance with the present application;

FIG. 49 is a top view of the first magnetic field enhancement assembly of the embodiment of FIG. 47 provided by the present application;

fig. 50 is a schematic diagram of resonance frequencies of a dual-core magnetic field enhancement device according to an embodiment of the present application.

Reference numerals illustrate: the dual nuclear magnetic field enhanced device 30, the first cylindrical magnetic field enhancer 810, the first accommodation space 819, the second cylindrical magnetic field enhancer 820, the first cylindrical support 811, the first outer surface 801, the first magnetic field enhancing component 812, the first inner surface 802, the second cylindrical support 821, the second outer surface 803, the second magnetic field enhancing component 822, the first resonance control circuit 851, the second resonance control circuit 852, the first dielectric layer 100, the first surface 101, the second surface 102, the first end 103, the second end 104, the first electrode layer 110, the second electrode layer 120, the first external capacitance 405, the second dielectric layer 831, the third surface 805, the fourth surface 806, the third end 881, the fourth end 882, the seventh electrode layer 832, the eighth electrode layer 833, the ninth electrode layer 834, the sixth structural capacitance 807, the seventh structural capacitance 808, the first fixed structure 883, the second fixed structure 884.

Detailed Description

In order that the application may be readily understood, a more complete description of the application will be rendered by reference to the appended drawings. Embodiments of the application are illustrated in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

It will be understood that the terms first, second, etc. as used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another element. For example, a first resistance may be referred to as a second resistance, and similarly, a second resistance may be referred to as a first resistance, without departing from the scope of the application. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

It is to be understood that in the following embodiments, "connected" is understood to mean "electrically connected", "communicatively connected", etc., if the connected circuits, modules, units, etc., have electrical or data transfer between them.

As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," and/or the like, specify the presence of stated features, integers, steps, operations, elements, components, or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or groups thereof. Also, the term "and/or" as used in this specification includes any and all combinations of the associated listed items.

Referring to fig. 1, the present application provides a dual nuclear magnetic field enhancement device 30. The dual nuclear magnetic field enhancer 30 includes a first cylindrical magnetic field enhancer 810 and a second cylindrical magnetic field enhancer 820. The first cylindrical magnetic field enhancer 810 encloses a first accommodation space 819. The first cylindrical magnetic field enhancer 810 is used for enhancing the nuclear magnetic signal of hydrogen nuclei at the detection site. The second cylindrical magnetic field enhancer 820 is disposed within the first accommodation space 819. The second cylindrical magnetic field enhancer 820 encloses a second receiving space 829. The detection portion may be accommodated in the second accommodating space 829. The second cylindrical magnetic field enhancer 820 is used for enhancing the nuclear magnetic signal of the non-hydrogen sub-nuclei of the detection site. The first accommodation space 819 is larger than the second accommodation space 829. The detection portion may be stored in the first accommodation space 819 while being stored in the second accommodation space 829.

In this embodiment, the detection portion may be an arm, a leg, an abdomen, or the like of a human or an animal. The detection site includes a hydrogen proton core and a non-hydrogen proton core other than the hydrogen proton core. The non-hydrogen proton core includes ²³Na、³¹P、¹⁹ F and the like. The non-hydrogen nuclei can provide rich biological information such as metabolism, ion exchange, etc. The diameter of the first cylindrical magnetic field enhancer 810 is greater than the diameter of the second cylindrical magnetic field enhancer 820. The first cylindrical magnetic field enhancer 810 is nested outside the second cylindrical magnetic field enhancer 820. The first cylindrical magnetic field enhancer 810 and the second cylindrical magnetic field enhancer 820 are used for detecting different target nuclei of the same region, and MRI imaging information corresponding to the different target nuclei of the detection region can be displayed.

The second cylindrical magnetic field enhancer 820 is disposed within the first accommodation space 819. The second cylindrical magnetic field enhancer 820 is disposed inside the binuclear magnetic field enhancing device 30. The first cylindrical magnetic field enhancer 810 is disposed outside the binuclear magnetic field enhancing device 30. The second cylindrical magnetic field enhancer 820 is nested with the first cylindrical magnetic field enhancer 810. The binuclear magnetic field enhancement means 30 can enhance the nuclear magnetic signal of hydrogen nuclei and the nuclear magnetic signal of non-hydrogen nuclei in the detection site. The dual nuclear magnetic field enhancement device 30 achieves simultaneous enhancement of two signal fields of dual nuclear MRI for hydrogen proton nuclei and non-hydrogen proton nuclei. The binuclear magnetic field enhancement device 30 may have a higher magnetic field enhancement effect than the conventional art. The dual nuclear magnetic field enhancement device 30 may assist the MRI apparatus in obtaining higher quality images when applied to MRI apparatus imaging.

The dual nuclear magnetic field enhancement device 30 is an image enhanced super-structured surface device for dual nuclear MRI. The image-enhanced super-structured surface device of the dual-core MRI can enhance the nuclear magnetic signal of hydrogen nuclei and the nuclear magnetic signal of non-hydrogen nuclei in the detection site. The image enhancement super-structured surface device of the dual-core MRI realizes the simultaneous enhancement of two signal fields of the dual-core MRI of hydrogen proton core and non-hydrogen proton core.

The diameters and lengths of the first and second cylindrical magnetic field intensifiers 810 and 820 may be determined according to the detection sites. In one embodiment, the first cylindrical magnetic field enhancer 810 is 350mm in length. The diameter of the first cylindrical magnetic field enhancer 810 is 120mm. The diameter of the second cylindrical magnetic field enhancer 820 is 100mm. The second cylindrical magnetic field enhancer 820 has a length of 450mm.

Referring to fig. 2 and 3, in one embodiment, the first cylindrical magnetic field enhancer 810 includes a first cylindrical support 811 and a plurality of first magnetic field enhancing assemblies 812. The first cylindrical bracket 811 has a first outer surface 801 and a first inner surface 802. The first outer surface 801 surrounds the first inner surface 802. The first outer surface 801 is disposed in spaced opposition to the first inner surface 802. The first inner surface 802 encloses the first accommodation space 819.

The first magnetic field enhancement member 812 has an extension direction identical to that of the first central axis of the first cylindrical bracket 811, and is disposed at intervals around the first central axis of the first cylindrical bracket 811 on the first outer surface 801. Each of the first magnetic field enhancement assemblies 812 has oppositely disposed first and second ends. The first ends of the plurality of first magnetic field enhancement components 812 are connected in sequence. The first ends of the plurality of first magnetic field enhancement components 812 are electrically connected one to the other in a direction about the first central axis. The second ends of the plurality of first magnetic field enhancement components 812 are connected in sequence. The second ends of the plurality of first magnetic field enhancement members 812 are electrically connected one by one in a direction surrounding the first central axis of the first cylindrical bracket 811. When the magnetic field enhancer is applied to MRI equipment, the resonance frequency of the first cylindrical magnetic field enhancer (810) is the same as the working frequency, so that the nuclear magnetic signal of hydrogen nuclei of the detection part can be enhanced, and the imaging of the MRI equipment is facilitated.

In one embodiment, the first cylindrical magnetic field enhancer 810 further includes a first annular conductive sheet 861, a second annular conductive sheet 862, and a first fixation structure 883. The first annular conductive piece 861 and the second annular conductive piece 862 are provided at opposite ends of the first cylindrical bracket 811, respectively. The first cylindrical holder 811 has a first end and a second end disposed opposite to each other in the direction of the central axis. The first annular conductive piece 861 is provided at a first end of the first cylindrical holder 811. The second annular conductive piece 862 is provided at a second end of the first cylindrical holder 811.

The first annular conductive piece 861 is disposed around the central axis of the first cylindrical holder 811. That is, the central axis passes through the geometric center point of the first annular conductive sheet 861. The second annular conductive piece 862 is disposed around the central axis of the first cylindrical holder 811. That is, the central axis passes through the geometric center point of the second annular conductive tab 862.

In one embodiment, each of the first magnetic field enhancement assemblies 812 may have a strip-like structure extending along the central axis. Both ends of each of the first magnetic field enhancement members 812 are connected to the first annular conductive piece 861 and the second annular conductive piece 862, respectively. That is, each of the first magnetic field enhancement assemblies 812 has oppositely disposed first and second ends. The first ends of the plurality of first magnetic field enhancement assemblies 812 are sequentially connected by the first annular conductive sheet 861. The second ends of the plurality of first magnetic field enhancement assemblies 812 are connected in sequence by the second annular conductive sheet 862. The plurality of first magnetic field enhancement members 812 are fixedly connected by the first cylindrical holder 811, the first annular conductive piece 861, and the second annular conductive piece 862.

In one embodiment, the first annular conductive sheet 861 is a closed ring, and the first ends of the plurality of first magnetic field enhancement assemblies 812 are sequentially connected to form a closed structure. The second annular conductive sheet 862 is a closed ring, and connects the second ends of the plurality of first magnetic field enhancement components 812 in sequence to form a closed structure.

In one embodiment, the first cylindrical magnetic field enhancer 810 further includes a plurality of first fixation structures 883. The plurality of first fixing structures 883 are disposed at intervals around the central axis of the first cylindrical bracket 811 on the first outer surface 801. And the plurality of first fixing structures 883 are provided at intervals at both ends of the first cylindrical bracket 811. Each of the first magnetic field enhancement assemblies 812 corresponds to the first fixed structure 883 of the first end of the first cylindrical bracket 811 and the first fixed structure 883 of the second end of the first cylindrical bracket 811, respectively. One of the first magnetic field enhancement members 812 is fixed by the first fixing structures 883 at both ends of the first cylindrical bracket 811, thereby fixing the first magnetic field enhancement member 812 to the first outer surface 801 of the first cylindrical bracket 811.

In one embodiment, the plurality of first fixing structures 883 may be through slots. The through slot may be used to insert the first magnetic field enhancement component 812. Each of the two first fixing structures 883 fixes two ends of one of the first magnetic field enhancement assemblies 812. The first magnetic field enhancement assembly 812 may be secured to the first outer surface 801 of the first cylindrical support 811 by the first securing structure 883.

In one embodiment, the first annular conductive sheet 861 and the second annular conductive sheet 862 may be made of a metal material such as gold, silver, copper, or the like.

In one embodiment, the first magnetic field enhancement component 812 may have a length of 150mm to 400mm. In one embodiment, the first magnetic field enhancing component 812 has a length of 250mm.

Referring to fig. 4, in one embodiment, the first cylindrical support 811 has a first inner surface 802. The first inner surface 802 encloses the first accommodation space 819. The first inner surface 802 is spaced opposite the first outer surface 801. The first outer surface 801 is disposed around the first inner surface 802. The second cylindrical magnetic field enhancer 820 includes a second cylindrical support 821 and a plurality of second magnetic field enhancing members 822. The second cylindrical holder 821 is disposed in the first accommodation space 819. The second cylindrical support 821 has a second outer surface 803 and a second inner surface 804.. The second outer surface 803 is disposed in spaced opposition to the first inner surface 802. The plurality of second magnetic field enhancement elements 822 are disposed at intervals on the second outer surface 803. The second magnetic field enhancing member 822 extends in the same direction as the second central axis of the second cylindrical holder 821. Each of the second magnetic field enhancement assemblies 822 has a first end and a second end disposed opposite to each other, the first ends of the plurality of second magnetic field enhancement assemblies 822 are connected in sequence, and the second ends of the plurality of second magnetic field enhancement assemblies 822 are connected in sequence.

The second inner surface 804 encloses a second receiving space 829. The second accommodating space 829 is used for placing the detection site, such as an arm, a leg, an abdomen, or the like.

Each of the second magnetic field enhancement assemblies 822 has oppositely disposed first and second ends. The first ends of the plurality of second magnetic field enhancement assemblies 822 are connected in sequence. The first ends of the plurality of second magnetic field enhancement members 822 are electrically connected one by one in a direction surrounding the second central axis. The second ends of the plurality of second magnetic field enhancement assemblies 822 are connected in sequence. The second ends of the plurality of second magnetic field enhancement components 822 are electrically connected one to the other in a direction surrounding the second central axis.

The plurality of second magnetic field enhancing members 822 are connected by first and second ends to form a resonant tank having a particular resonant frequency. When the magnetic field enhancement assemblies 822 are applied to an MRI device, when the resonance frequency of a resonance circuit formed by the second magnetic field enhancement assemblies 822 is the same as the working frequency, the nuclear magnetic signal of the non-hydrogen sub-core of the detection part can be enhanced, and the imaging of the MRI device is facilitated.

In one embodiment, the second cylindrical magnetic field enhancer 820 further includes a third annular conductive sheet 866, a fourth annular conductive sheet 867, and a second securing structure 884. The third annular conductive piece 866 and the fourth annular conductive piece 867 are respectively disposed at two opposite ends of the second cylindrical support 821. The second cylindrical support 821 has a first end and a second end disposed opposite to each other along the central axis direction. The third annular conductive piece 866 is disposed at a first end of the second cylindrical support 821. The fourth annular conductive piece 867 is disposed at a second end of the second cylindrical support 821.

The third annular conductive piece 866 is disposed around the central axis of the second cylindrical holder 821. That is, the central axis passes through the geometric center point of the third annular conductive tab 866. The fourth annular conductive piece 867 is disposed around the central axis of the second cylindrical holder 821. That is, the central axis passes through the geometric center point of the fourth annular conductive sheet 867.

In one embodiment, each of the second magnetic field enhancement assemblies 822 may have a bar-like structure extending along the central axis. Both ends of each of the second magnetic field enhancement members 822 are connected to the third annular conductive piece 866 and the fourth annular conductive piece 867, respectively. That is, each of the second magnetic field enhancement assemblies 822 has oppositely disposed first and second ends. The first ends of the plurality of second magnetic field enhancement members 822 are connected in sequence by the third annular conductive sheet 866. The second ends of the plurality of second magnetic field enhancement members 822 are connected in sequence by the fourth annular conductive sheet 867. The plurality of second magnetic field enhancement members 822 are fixedly connected by the second cylindrical support 821, the third annular conductive piece 866, and the fourth annular conductive piece 867.

In one embodiment, the third annular conductive sheet 866 is a closed ring, and connects the first ends of the plurality of second magnetic field enhancement assemblies 822 sequentially to form a closed structure. The fourth annular conductive sheet 867 is a closed ring, and connects the second ends of the second magnetic field enhancement assemblies 822 sequentially to form a closed structure.

In one embodiment, the second cylindrical magnetic field enhancer 820 further includes a plurality of second fixation structures 884. The plurality of second fixing structures 884 are disposed at intervals around the central axis of the second cylindrical support 821 on the second outer surface 803. And the second fixing structures 884 are arranged at intervals at two ends. Each of the second magnetic field enhancement assemblies 821 corresponds to the second fixed structure 884 of the first end of the second cylindrical support 821 and the second fixed structure 884 of the second end of the second cylindrical support 821, respectively. One of the second magnetic field enhancing members 822 is fixed by the second fixing structures 884 at both ends of the second cylindrical support 821, and the second magnetic field enhancing member 82 is further fixed to the second outer surface 803 of the second cylindrical support 821.

In one embodiment, the plurality of second fixation structures 884 may be through slots. The through slot may be used to insert the second magnetic field enhancement assembly 822. Each two second fixing structures 884 respectively fix two ends of one second magnetic field enhancement component 822. The second magnetic field enhancing assembly 822 may be fixed to the second outer surface 803 of the second cylindrical support 821 by the second fixing structure 884.

Referring to fig. 5, in one embodiment, the dual-core magnetic field enhancement device 30 further includes a plurality of first resonance control circuits 851. One of the first resonance control circuits 851 is electrically connected to one of the first magnetic field enhancement components 812 for controlling the operation state of the first magnetic field enhancement component 812.

In this embodiment, the operating states of the first magnetic field enhancement component 812 include a detuned state and a resonant state. The detuned state refers to the first resonance control circuit 851 controlling the resonant circuit in which the first magnetic field enhancement component 812 is located not to resonate during the radio frequency transmission stage, and to assume a detuned state. The resonance state refers to that in the radio frequency receiving stage, the first resonance control circuit 851 adjusts and controls the capacitance, inductance and other electronic elements of itself, so that the resonance circuit where the first magnetic field enhancement component 812 is located is in the resonance state. At this time, the resonance frequency of the resonance circuit is the same as the working frequency, so that the nuclear magnetic signal of the hydrogen nuclei of the detection part can be enhanced, and the imaging of the MRI equipment is facilitated.

In one embodiment, the first resonance control circuit 851 includes a circuit structure described in any one of the following embodiments, for adjusting the resonance state.

Referring to fig. 6, in one embodiment, the dual-core magnetic field enhancement device 30 further includes a plurality of second resonant control circuits 852. One of the second resonance control circuits 852 is electrically connected to one of the second magnetic field enhancement assemblies 822 for controlling the operation state of the second magnetic field enhancement assembly 822.

In this embodiment, the operating states of the second magnetic field enhancement component 822 include a detuned state and a resonant state. The detuned state refers to that the resonant circuit in which the second resonant control circuit 852 is located does not resonate during the radio frequency transmission stage, and exhibits a detuned state. The resonant state refers to that, during the rf receiving stage, the second resonance control circuit 852 adjusts and controls the capacitance, inductance, and other electronic components of itself, so that the resonant circuit formed by the first magnetic field enhancement component 812 is in a resonant state. At this time, the resonance frequency of the resonance circuit is the same as the working frequency, so that the nuclear magnetic signal of the non-hydrogen nuclear of the detection part can be enhanced, and the imaging of the MRI equipment is facilitated.

In one embodiment, the second resonance control circuit 852 includes a circuit structure as described in any one of the following embodiments, for adjusting the resonance state.

In one embodiment, the central axis of the first cylindrical magnetic field enhancer 810 coincides with the central axis of the second cylindrical magnetic field enhancer 820. The first cylindrical magnetic field enhancer 810 and the second cylindrical magnetic field enhancer 820 share a central axis, which is advantageous for forming a symmetrical and uniform magnetic field around the detection site.

The middle section of the first cylindrical magnetic field enhancer 810 coincides with the middle section of the second cylindrical magnetic field enhancer 820. The middle cross section of the first cylindrical magnetic field enhancer 810 refers to a cross section perpendicular to the central axis direction at the middle position of the first cylindrical magnetic field enhancer 810. The middle cross section of the second cylindrical magnetic field enhancer 820 refers to a cross section perpendicular to the central axis direction at the middle position of the second cylindrical magnetic field enhancer 820.

The length of the first cylindrical magnetic field enhancer 810 is smaller than the length of the second cylindrical magnetic field enhancer 820 in the direction of the central axis. And, both ends of the first cylindrical magnetic field enhancer 810 are not coplanar with both ends of the second cylindrical magnetic field enhancer 820. That is, the first end of the first cylindrical magnetic field enhancer 810 is offset from the first end of the second cylindrical magnetic field enhancer 820. The second end of the first cylindrical magnetic field enhancer 810 is offset from the second end of the second cylindrical magnetic field enhancer 820. The first cylindrical magnetic field enhancer 810 and the second cylindrical magnetic field enhancer 820 have different lengths and the two ends are not coplanar, and the end rings of the first cylindrical magnetic field enhancer 810 and the second cylindrical magnetic field enhancer 820 may be staggered. The end rings of the first cylindrical magnetic field enhancer 810 and the second cylindrical magnetic field enhancer 820 are staggered, thereby avoiding stray capacitance at the port locations and reducing coupling effects between the first cylindrical magnetic field enhancer 810 and the second cylindrical magnetic field enhancer 820.

In one embodiment, the first end of the first cylindrical magnetic field enhancer 810 and the first end of the second cylindrical magnetic field enhancer 820 are at least 20mm apart on the same side. The second end of the first cylindrical magnetic field enhancer 810 is at least 20mm different from the second end of the second cylindrical magnetic field enhancer 820. During the radio frequency receiving stage, the two ends of the first cylindrical magnetic field enhancer 810 and the second cylindrical magnetic field enhancer 820 are at least different by 20mm in dislocation, so that stray capacitance is reduced, and further, coupling effect between the two is reduced, so that frequencies of the first cylindrical magnetic field enhancer 810 and the second cylindrical magnetic field enhancer 820 are more stable, and image enhancement is more facilitated.

Referring to fig. 7, in one embodiment, the second magnetic field enhancement component 822 includes a first dielectric layer 100, a first electrode layer 110, a second electrode layer 120, and a first external capacitor 405. The first dielectric layer 100 includes a first surface 101 and a second surface 102 disposed in a spaced apart relation. The first dielectric layer 100 has a first end 103 and a second end 104 disposed opposite each other. The first electrode layer 110 is disposed on the first surface 101. The first electrode layer 110 covers a portion of the first surface 101. The first electrode layer 110 is disposed proximate the second end 104. The second electrode layer 120 is disposed on the first surface 101. The second electrode layer 120 is spaced apart from the first electrode layer 110. The second electrode layer 120 covers part of the first surface 101. The second electrode layer 120 is disposed proximate the first end 103. One end of the first external capacitor 405 is connected to one end of the second electrode layer 120 away from the first end 103. The other end of the first external capacitor 405 is connected to an end of the first electrode layer 110 away from the second end 104. And the first external capacitor 405 is disposed near the middle of the first dielectric layer 100.

The first external capacitor 405 may be a fixed capacitor or an adjustable capacitor. When the frequency of the rf coil is determined, a suitable fixed capacitor may be selected so that the resonant frequency of the second cylindrical magnetic field enhancer 820 is equal to the frequency of the rf coil, thereby enhancing the magnetic field. The first external capacitor 405 may employ an adjustable capacitor when the environment in which the second cylindrical magnetic field enhancer 820 is used is not determined, for example, the frequency of a radio frequency coil is not determined. The resonant frequency of the second cylindrical magnetic field enhancer 820 can be adjusted by adjusting the adjustable capacitance so that the second cylindrical magnetic field enhancer 820 is adaptable to different environments.

In one embodiment, one end of the first external capacitor 405 is connected to one end of the first electrode layer 110 near the second electrode layer 120. The other end of the first external capacitor 405 is connected to one end of the second electrode layer 120, which is close to the first electrode layer 110. The connection position of the first external capacitor 405 and the first electrode layer 110 and the second electrode layer 120 is close to the gap between the first electrode layer 110 and the second electrode layer 120. In the above structure, the wires connecting the first external capacitor 405 with the first electrode layer 110 and the second electrode layer 120 are relatively short. In this embodiment, the first external capacitor 405 may be connected in such a manner that the resistance between the first electrode layer 110 and the second electrode layer 120 is smaller, so as to reduce the energy consumption of the second magnetic field enhancing component 822.

Referring to fig. 8, in one embodiment, the width of the first electrode layer 110 is smaller than the width of the first dielectric layer 100 in a direction surrounding the second central axis of the second cylindrical support 821. The width of the second electrode layer 120 is smaller than the width of the first dielectric layer 100.

In this embodiment, the width of the first electrode layer 110 may be understood as the width in the vertical direction in fig. 8. The length of the first electrode layer 110 is the length in the horizontal line direction in fig. 8. The first electrode layer 110 and the second electrode layer 120 form a transmission line, and a parallel connection between the first external capacitors 405 in the plurality of second magnetic field enhancement components 822 is realized. The width of the first electrode layer 110 is smaller than the width of the first dielectric layer 100, which may reduce the width of the transmission line, and thus the relative area between the electrode layers may be reduced. The width of the second electrode layer 120 is smaller than that of the first dielectric layer 100, so that the width of the transmission line becomes smaller, and the relative area between the electrode layers becomes smaller.

Therefore, the width of the transmission line becomes smaller, reducing the stray capacitance formed. Therefore, without affecting the connection of the first external capacitor 405 in the plurality of second magnetic field enhancement assemblies 822, stray capacitance is reduced, even distribution of magnetic fields is facilitated, and MRI image quality is improved.

Referring to fig. 9, in one embodiment, the second magnetic field enhancement component 822 includes a first dielectric layer 100, a first electrode layer 110, a second electrode layer 120, and a third capacitor 223, a first inductor 241, and a first switching circuit 631. One end of the third capacitor 223 is connected to the first electrode layer 110. The other end of the third capacitor 223 is connected to the second electrode layer 120. One end of the first inductor 241 is connected to the second electrode layer 120. The first switch circuit 631 is connected between the other end of the first inductor 241 and the first electrode layer 110. The first switch circuit 631 is configured to be turned off during a radio frequency reception phase. The first switch circuit 631 is further configured to be turned on during a radio frequency transmission stage, so that a parallel resonance occurs in the circuit, and the circuit is in a high-resistance state.

The first switch circuit 631 is configured to be turned off during a radio frequency reception phase. The first electrode layer 110 and the second electrode layer 120 are connected through the third capacitor 223. The first switching circuit 631 and the first inductor 241 do not participate in the circuit conduction. The first switch circuit 631 is further configured to be turned on during a radio frequency transmission stage, and the third capacitor 223 is connected in parallel with the first inductor 241, and performs parallel resonance, so that the third resonant circuit 400 is in a high-resistance state. The circuit is broken between the second structure capacitor 302 and the third structure capacitor 303. During the rf emission phase, almost no current flows between the second structural capacitor 302 and the third structural capacitor 303, and the magnetic field of the loop where the second magnetic field enhancing component 822 is located is reduced, so that the influence of the second magnetic field enhancing component 822 on the magnetic field during the rf signal emission phase is reduced, thereby reducing the artifact of the detected image and improving the definition of the detected image.

The first switching circuit 631 may be controlled by a control circuit. In one embodiment, the first switching circuit 631 includes a switching element and a control terminal. One end of the switching element is connected to one end of the first inductor 241 remote from the second electrode layer 120. The other end of the switching element is connected to the first electrode layer 110. The control end is connected with an external control device. The control terminal is used for receiving the closing and opening commands. And in the radio frequency transmitting stage, the control device outputs a closing command to the control end. When the control terminal receives a close command, the first inductor 241 is electrically connected to the first electrode layer 110. The first inductor 241 is connected in parallel with the third capacitor 223, and generates parallel resonance, and the circuit is in a high-resistance state. Almost no current flows between the first electrode layer 110 and the second electrode layer 120.

In the radio frequency receiving stage, the control device outputs a closing command to the control end. When the control terminal receives a turn-off command, the first inductor 241 is turned off from the first electrode layer 110. The first electrode layer 110 and the third capacitor 223 are connected in series with the second electrode layer 120 to form a part of a resonant circuit, and the second cylindrical magnetic field enhancer 820 formed by the plurality of second magnetic field enhancing members 822 resumes resonance, thereby greatly enhancing the rf receiving field.

In one embodiment, the first switching circuit 631 includes a seventh diode 213 and an eighth diode 214. The anode of the seventh diode 213 is connected to the first electrode layer 110. The negative electrode of the seventh diode 213 is connected to the other end of the first inductor 241. The anode of the eighth diode 214 is connected to the other end of the first inductor 241, and the cathode of the eighth diode 214 is connected to the first electrode layer 110.

The second magnetic field enhancement assembly 822 is applied to a magnetic resonance system to enhance the magnetic field strength of the human feedback signal during the radio frequency receive phase. In the radio frequency transmitting stage of the magnetic resonance system, the magnetic field energy in the transmitting stage is more than 1000 times of the magnetic field energy in the receiving stage. The second magnetic field enhancement component 822 of the transmit phase has an induced voltage between tens of volts and hundreds of volts. The second magnetic field enhancement component 822 in the receive phase has an induced voltage of less than 1V.

The seventh diode 213 and the eighth diode 214 are connected in anti-parallel. In the radio frequency transmitting stage, the radio frequency coil transmits radio frequency transmitting signals, and the field intensity of the magnetic field is larger. The second magnetic field enhancement assembly 822 generates a larger induced voltage. The voltage applied across the seventh diode 213 and the eighth diode 214 is alternately positive and negative. The applied voltage exceeds the turn-on voltage of the seventh diode 213 and the eighth diode 214, and the seventh diode 213 and the eighth diode 214 are turned on. The third capacitor 223 is connected in parallel with the first inductor 241, and generates parallel resonance, so that the third resonant circuit 400 is in a high-resistance state. In the rf signal emission stage, almost no current flows between the first electrode layer 110 and the second electrode layer 120, and the magnetic field generated by the second magnetic field enhancing component 822 is weakened, so that the influence of the second magnetic field enhancing component 822 on the magnetic field in the rf signal emission stage is reduced, thereby reducing the artifact of the detected image and improving the definition of the detected image.

In the radio frequency receiving stage, the detection part transmits a feedback signal, and the field intensity of the magnetic field is smaller. The second magnetic field enhancement assembly 822 generates a smaller induced voltage. The applied voltage cannot reach the turn-on voltage of the seventh diode 213 and the eighth diode 214, and the seventh diode 213 and the eighth diode 214 are not turned on. The first electrode layer 110 and the second electrode layer 120 are connected through the third capacitor 223, and the second cylindrical magnetic field enhancer 820 composed of the plurality of the second magnetic field enhancing components 822 is in a resonance state, and plays a role in enhancing a magnetic field.

In one embodiment, the turn-on voltages of the seventh diode 213 and the eighth diode 214 are each between 0 and 1V. In one embodiment, the turn-on voltages of the seventh diode 213 and the eighth diode 214 are the same, so that the magnetic field strength is continuously increased during the rf receiving phase of the second cylindrical magnetic field booster 820, thereby improving the stability of the feedback signal. In one embodiment, the turn-on voltage of the seventh diode 213 and the eighth diode 214 is 0.8V.

In one embodiment, the seventh diode 213 and the eighth diode 214 have the same model, and the voltage drops after the seventh diode 213 and the eighth diode 214 are turned on are the same, so that the magnetic field strength of the second cylindrical magnetic field enhancer 820 increases by the same magnitude in the radio frequency receiving stage, and the stability of the feedback signal is further improved.

Referring to fig. 10, in one embodiment, the first switch circuit 631 includes a fifth enhancement MOS transistor 235 and a sixth enhancement MOS transistor 236. The drain and the gate of the fifth enhancement MOS transistor 235 are respectively connected to one end of the first inductor 241 away from the second electrode layer 120. The source of the fifth enhancement MOS transistor 235 is connected to the first electrode layer 110. The drain and the gate of the sixth enhancement MOS transistor 236 are respectively connected to the first electrode layer 110. The source electrode of the sixth enhancement MOS transistor 236 is connected to the end of the first inductor 241 away from the second electrode layer 120.

The fifth enhancement MOS tube 235 and the sixth enhancement MOS tube 236 are connected in anti-parallel. In the radio frequency transmitting stage, the radio frequency coil transmits radio frequency transmitting signals, and the field intensity of the magnetic field is larger. The second magnetic field enhancement assembly 822 generates a larger induced voltage. The voltages applied to the two ends of the fifth enhancement MOS tube 235 and the sixth enhancement MOS tube 236 are alternately positive and negative. When the voltage applied exceeds the channel turn-on voltage of the fifth enhancement MOS tube 235 and the sixth enhancement MOS tube 236, the source-drain electrode of the fifth enhancement MOS tube 235 is turned on and the source-drain electrode of the sixth enhancement MOS tube 236 is turned on alternately. The third capacitor 223 is connected in parallel with the first inductor 241, and generates parallel resonance, so that the third resonant circuit 400 is in a high-resistance state. In the rf signal emission stage, almost no current flows between the first electrode layer 110 and the second electrode layer 120, and the magnetic field generated by the second magnetic field enhancing component 822 is weakened, so that the influence of the second magnetic field enhancing component 822 on the magnetic field in the rf signal emission stage is reduced, thereby reducing the artifact of the detected image and improving the definition of the detected image.

In the radio frequency receiving stage, the detection part transmits a feedback signal, and the field intensity of the magnetic field is smaller. The second magnetic field enhancement assembly 822 generates a smaller induced voltage. The voltage applied cannot reach the channel conduction voltage of the fifth enhancement MOS tube 235 and the sixth enhancement MOS tube 236, and the source drain of the fifth enhancement MOS tube 235 is conducted and the source drain of the sixth enhancement MOS tube 236 is not conducted. The first electrode layer 110 and the second electrode layer 120 are connected through the third capacitor 223. The second cylindrical magnetic field enhancer 820 composed of the plurality of second magnetic field enhancing members 822 is in a resonance state and plays a role of enhancing a magnetic field.

In one embodiment, the channel turn-on voltages of the fifth enhancement MOS transistor 235 and the sixth enhancement MOS transistor 236 are both between 0 and 1V, and the channel turn-on voltages of the fifth enhancement MOS transistor 235 and the sixth enhancement MOS transistor 236 are the same, so that the second cylindrical magnetic field enhancer 820 can stably enhance the magnetic field in the radio frequency receiving stage, and the feedback signal can be stably output. In one embodiment, the channel turn-on voltage of the fifth enhancement MOS transistor 235 and the sixth enhancement MOS transistor 236 is 0.8V.

Referring to fig. 11, in one embodiment, the second magnetic field enhancement component 822 further includes a fourth capacitance 224. The fourth capacitor 224 is connected between the third capacitor 223 and the first electrode layer 110. The fourth capacitor 224 is connected in series with the third capacitor 223. The fourth capacitor 224 is configured to reduce the voltage division of the third capacitor 223, improve the capability of the second magnetic field enhancing component 822 to resist a strong magnetic field, and reduce the probability of breakdown of the third capacitor 223.

In one embodiment, the third capacitor 223 and the fourth capacitor 224 have equal capacitance values. In the rf receiving stage, the voltage division on the third capacitor 223 and the fourth capacitor 224 are the same, so as to improve the uniformity of the magnetic field, reduce the distortion caused by the inconsistent enhancement of the magnetic field, and improve the image quality.

Referring to fig. 12, a second magnetic field enhancement assembly 822 is provided in accordance with an embodiment of the present application. The second magnetic field enhancement assembly 822 includes a first electrode layer 110, a second electrode layer 120, and a first dielectric layer 100. The first dielectric layer 100 includes a first surface 101 and a second surface 102 disposed opposite each other. The first electrode layer 110 is disposed on the first surface 101. The first electrode layer 110 covers a portion of the first surface 101. The second electrode layer 120 is disposed on the second surface 102. The second electrode layer 120 covers a portion of the second surface 102. The orthographic projection of the first electrode layer 110 on the first dielectric layer 100 and the orthographic projection of the second electrode layer 120 on the first dielectric layer 100 are overlapped to form a first structural capacitor 150.

The first electrode layer 110 covering a part of the first surface 101 means that the first surface 101 is still partly uncovered by the first electrode layer 110. The second electrode layer 120 covering a part of the second surface 102 means that the second surface 102 is still partly uncovered by the second electrode layer 120. The first electrode layer 110 and the second electrode layer 120 overlap in part in the orthographic projection of the first dielectric layer 100. The portion of the first electrode layer 110 and the second electrode layer 120 that are disposed opposite to each other constitutes the first structural capacitor 150. The portion of the first electrode layer 110 and the second electrode layer 120, which do not overlap in the orthographic projection of the first dielectric layer 100, may serve as a transmission line, and serve as an equivalent inductance. The first structural capacitance 150 and the equivalent inductance may form an LC tank circuit. When the magnetic resonance frequency is lower, the first structural capacitor 150 with a smaller capacitance value can reduce the resonance frequency of the second cylindrical magnetic field enhancer 820 formed by the plurality of second magnetic field enhancing components 822 to the frequency of the radio frequency coil of the magnetic resonance system, so that the magnetic field strength can be effectively improved.

The portion of the second magnetic field enhancement member 822 that forms the first structural capacitance 150 produces a magnetic field that is parallel to the plane of the first dielectric layer 100. Whereas a magnetic field parallel to the first dielectric layer 100 is essentially undetectable, belonging to an ineffective magnetic field. The magnetic field generated by the portion of the second magnetic field enhancing member 822 that constitutes the equivalent inductance is perpendicular to the first dielectric layer 100, and can generate an effective magnetic field that acts on the detection region.

In one embodiment, the area occupied by the overlapping portion of the orthographic projection of the first electrode layer 110 on the first dielectric layer 100 and the orthographic projection of the second electrode layer 120 on the first dielectric layer 100 is less than half the area of the first surface 101 or half the area of the second surface 102. Thus, the area of the first dielectric layer 100 constituting the first structural capacitance 150 is less than half the area of the first dielectric layer 100. By reducing the area of the first structural capacitance 150, the power consumption of the first structural capacitance 150 can be reduced. The area of the first dielectric layer 100 constituting the first structural capacitor 150 is smaller than half the area of the first dielectric layer 100, so that the coupling degree between the second magnetic field enhancement component 822 and other cascaded super-structure surfaces can be reduced, and the performance of the second magnetic field enhancement component 822 is significantly improved.

The first dielectric layer 100 may function to support the first electrode layer 110 and the second electrode layer 120. The first dielectric layer 100 may have a rectangular plate-like structure. The first dielectric layer 100 may be an insulating material. In one embodiment, the material of the first dielectric layer 100 may be a glass fiber epoxy plate. The first electrode layer 110 and the second electrode layer 120 may have a rectangular plate-like structure. The materials of the first electrode layer 110 and the second electrode layer 120 may be composed of an electrically conductive non-magnetic material. In one embodiment, the materials of the first electrode layer 110 and the second electrode layer 120 may be metal materials such as gold, silver, copper, etc.

In one embodiment, the thicknesses of the first electrode layer 110 and the second electrode layer 120 may be equal. The first electrode layer 110, the second electrode layer 120, and the first dielectric layer 100 are stacked. The planes of the first electrode layer 110, the second electrode layer 120, and the first dielectric layer 100 may be substantially parallel.

Referring to fig. 13-15, in one embodiment, the first dielectric layer 100 includes opposing first and second ends 103, 104. The first electrode layer 110 extends from the second end 104 towards the first end 103. The second electrode layer 120 extends from the first end 103 towards the second end 104. The orthographic projection of the first electrode layer 110 on the first dielectric layer 100 overlaps the orthographic projection of the second electrode layer 120 on the first dielectric layer 100 to form the first structural capacitor 150. That is, the first electrode layer 110 and the second electrode layer 120 extend from opposite ends of the first dielectric layer 100 toward the middle of the first dielectric layer 100, respectively. The first electrode layer 110 and the second electrode layer 120 have overlapping portions in the front projection of the first dielectric layer 100. The overlapping portion is distant from both ends of the first dielectric layer 100.

In one embodiment, the length of the first electrode layer 110 and the second electrode layer 120 is less than three-fourths of the length of the first dielectric layer 100 and greater than one-fourth of the length of the first dielectric layer 100. In this range, the capacitance of the first capacitor 150 is smaller, so that the power consumption can be reduced. The effective inductor has a longer length, so that the magnetic field can be effectively enhanced, and the effect of the second magnetic field enhancing component 822 on enhancing the signal to noise ratio of the image is improved.

The overlapping portion of the orthographic projections of the first electrode layer 110 and the second electrode layer 120 is located in the middle of the first dielectric layer 100. In the overlapping portion, the first electrode layer 110, the first dielectric layer 100, and the second electrode layer 120 constitute the first structural capacitance 150. The first electrode layer 110 and the second electrode layer 120 may form a transmission line at a portion where the first dielectric layer 100 is not overlapped, and function as an inductance. The first electrode layer 110 and the second electrode layer 120 may also serve as equivalent inductances at the non-stacked portions of the first dielectric layer 100. The equivalent inductance and the first structural capacitor 150 form an LC tank circuit.

The first electrode layer 110 and the second electrode layer 120 have the same width in the shape of a bar and have the same extension direction. The extending directions of the first electrode layer 110 and the second electrode layer 120 may be in a straight line, so that the width of the second magnetic field enhancing member 822 can be reduced, and the volume of the second magnetic field enhancing member 822 can be reduced.

In one embodiment, the portion of the first electrode layer 110 and the second electrode layer 120 that coincides with the orthographic projection of the first dielectric layer 100 is located in the middle of the first dielectric layer 100. The first structural capacitance 150 is located in the middle of the first dielectric layer 100.

The middle portion of the first dielectric layer 100 may be a portion of the first dielectric layer 100 away from an edge of the first dielectric layer 100. The middle of the first dielectric layer 100 may be the middle of the first dielectric layer 100, or may be a position that is far to the left or far to the right in the middle of the first dielectric layer 100. The first structure capacitor 150 is located in the middle of the first dielectric layer 100, which can effectively improve the symmetry of the structure of the second magnetic field enhancement component 822, thereby improving the uniformity of the magnetic field.

In one embodiment, the target frequency range of the second magnetic field enhancement component 822 may be 60MHz to 150MHz. In one embodiment, the target frequency range of the second magnetic field enhancement assembly 822 may be 63.8MHz (1.5T for the main magnetic field B _O of the magnetic resonance system) or 128MHz (3T for the main magnetic field B _O of the magnetic resonance system). The first dielectric layer 100 may have a rectangular shape. The length of the first dielectric layer 100 may be 250 millimeters. The length of the portion where the front projections of the first electrode layer 110 and the second electrode layer 120 overlap with each other in the front projection of the first dielectric layer 100 may be 20 mm. I.e. the second magnetic field enhancing member 822 is capable of generating an effective magnetic field having a length of 230 mm. The second magnetic field enhancement assembly 822 is capable of producing a significant increase in the area of the effective magnetic field.

Referring to fig. 16 to 18, in one embodiment, the second magnetic field enhancement component 822 further includes a third electrode layer 130 disposed on the first surface 101. The third electrode layer 130 extends from the first end 103 towards the second end 104. The third electrode layer 130 covers a portion of the first surface 101 and is spaced apart from the first electrode layer 110. The second electrode layer 120 is electrically connected to the third electrode layer 130.

The thickness of the third electrode layer 130 may be the same as the thickness of the first electrode layer 110. The third electrode layer 130 may be connected to the second electrode layer 120 by bypassing the first dielectric layer 100. The third electrode layer 130 may also be connected to the second electrode layer 120 by a wire passing through the first dielectric layer 100. The second magnetic field enhancement assembly 822 may have an inductive effect with respect to the first electrode layer 110 and the third electrode layer 130 when placed in an excitation field of a magnetic resonance system.

The third electrode layer 130 may extend from the first end 103 of the first dielectric layer 100 toward the second end 104 and gradually approach the second electrode layer 120. The third electrode layer 130 is insulated from the first electrode layer 110, thereby preventing the first structural capacitor 150 formed by the first electrode layer 110 and the second electrode layer 120 from being shorted. The first electrode layer 110 and the third electrode layer 130 are disposed on the same side of the first dielectric layer 100. Accordingly, when the second magnetic field enhancing member 822 is mounted to a bracket, the first surface 101 is mounted toward a side away from the middle, and damage of the first electrode layer 110 and the third electrode layer 130 by the bracket can be prevented.

In one embodiment, the length of the third electrode layer 130 is less than one-half the length of the first electrolyte layer 100. The length of the third electrode layer 130 is greater than one third of the length of the first dielectric layer 100. In this range, the equivalent inductance formed by the third electrode layer 130 has a larger length, so that the area of the effective magnetic field generated by the second magnetic field enhancing element 822 can be effectively increased.

In one embodiment, the third electrode layer 130 is in a strip shape, and the extension direction and width of the third electrode layer 130 are the same as those of the first electrode layer 110. That is, the widths of the third electrode layer 130 and the first electrode layer 110 may be the same, and the third electrode layer 130 and the first electrode layer 110 may be positioned on the same straight line. The width of the first dielectric layer 100 may be equal to the width of the third electrode layer 130 and the first electrode layer 110, or slightly greater than the widths of the third electrode layer 130 and the first electrode layer 110. The width of the first dielectric layer 100 can be reduced as much as possible.

In one embodiment, the first dielectric layer 100 is provided with a via 103. An electrode material is disposed in the via 103. The third electrode layer 130 is electrically connected to the second electrode layer 120 through the electrode material. The electrode material may be the same as the material of the third electrode layer 130 and the second electrode layer 120, and thus the resistance may be reduced. In one embodiment, the electrode material in the via 103 is integrally formed with the first electrode and the third electrode layer 130.

In one embodiment, an end of the third electrode layer 130 near the first electrode layer 110 coincides with the orthographic projection of the via 103. The end of the second electrode layer 120 remote from the first electrode layer 110 coincides with the orthographic projection of the via 103. I.e. the third electrode layer 130 is in contact with the electrode material located in the via 103 close to the first surface 101. The second electrode layer 120 is in contact with the electrode material in the via 103 near the second surface 102. The third electrode layer 130, the second electrode layer 120 are thus electrically connected by the electrode material in the via 103.

Referring to fig. 19, in one embodiment, an end of the first electrode layer 110 near the second electrode layer 120 has a first opening 411. The second electrode layer 120 has a second opening 412 at an end near the first electrode layer 110. The orthographic projections of the first opening 411 and the second opening 412 on the first dielectric layer 100 coincide. The first opening 411 and the second opening 412 may have the same size. The first opening 411 and the second opening 412.

The overlapping portions of the front projection of the first electrode layer 110 and the second electrode layer 120 on the first dielectric layer 100 may constitute the first structural capacitance 150 when the second magnetic field enhancing component 822 is placed in an excitation field in a magnetic resonance system. The first opening 411 and the second opening 412 can optimize local magnetic field distribution, and can improve the detection effect of the specific position of the detection part.

Referring to fig. 20, in one embodiment, an end of the first electrode layer 110 near the second electrode layer 120 has a third opening 413. The third opening 413 is spaced from the first opening 411. The second electrode layer 120 has a fourth opening 414 near the end of the first electrode layer 110. The fourth opening 414 is spaced from the second opening 412. The orthographic projection of the third opening 413 and the fourth opening 414 on the first dielectric layer 100 coincides. It is understood that the first opening 411 and the third opening 413 may have the same shape and size. The second opening 412 and the fourth opening 414 may be the same size and shape. The distance between the first opening 411 and the third opening 413 may be the same. The distance between the second opening 412 and the fourth opening 414 may be the same. The third opening 413 and the fourth opening 414 may be located at overlapping portions of the first electrode layer 110 and the second electrode layer 120 orthographically projected on the first dielectric layer 100. The third opening 413 and the fourth opening 414 further optimize local magnetic field distribution, so as to improve the detection effect of the specific position of the detection part.

Referring to fig. 21, in one embodiment, the second magnetic field enhancement component 822 further includes a first switch control circuit 430, and the first switch control circuit 430 is connected between the first electrode layer 110 and the second electrode layer 120. The switch control circuit 430 is configured to be turned on during a radio frequency transmission phase and turned off during a radio frequency reception phase.

Both ends of the first switch control circuit 430 are connected between the first electrode layer 110 and the second electrode layer 120. I.e. the first switch control circuit 430 may be connected in parallel with the first structural capacitance 150. Accordingly, when the first switch control circuit 430 is turned on, the first electrode layer 110 and the second electrode layer 120 are electrically connected. When the first switch control circuit 430 is turned off, the first electrode layer 110 and the second electrode layer 120 are disconnected. The turn-on voltage of the first switch control circuit 430 may be greater than 1 volt. That is, when the voltage difference between the first electrode layer 110 and the second electrode layer is greater than 1 volt, the first switch control circuit 430 is turned on. When the voltage difference between the first electrode layer 110 and the second electrode layer 120 is less than 1 volt, the first switch control circuit 430 is turned off.

Referring to fig. 22, in the rf emission stage, the first switch control circuit 430 is turned on due to the larger voltage difference between the first electrode layer 110 and the second electrode layer 120. The first electrode layer 110 and the second electrode layer 120 are electrically connected. At this time, the first electrode layer 110 and the second electrode layer 120 cannot form the first structural capacitor 150. I.e. the second magnetic field enhancing component 822 does not have resonance properties. The second magnetic field enhancement component 822 is therefore unable to enhance the rf transmit field.

In the rf receiving stage, the voltage difference between the first electrode layer 110 and the second electrode layer 120 is smaller, the first switch control circuit 430 is turned off, and the first electrode layer 110 and the second electrode layer are turned off. The first electrode layer 110 and the second electrode layer 120 form the first structural capacitor 150. The second cylindrical magnetic field enhancer 820, thus formed by the second magnetic field enhancing assembly 822, has a good resonant frequency during the radio frequency reception phase. The second cylindrical magnetic field enhancer 820 may act to enhance the rf transmit field.

Referring to fig. 23, a diagram of MRI image enhancement effects of a second magnetic field enhancement assembly 822 provided in accordance with the prior art and embodiments of the present application is shown.

A is a body coil commonly adopted by a magnetic resonance system, the image signal-to-noise ratio is very low, and the particle sensation is serious;

b when the second magnetic field enhancing component 822 is not provided with the first switch control circuit 430, a lot of artifacts appear in the formed image due to the interference of the second magnetic field enhancing component 822 with the radio frequency transmission field;

c the second cylindrical magnetic field enhancer 820 formed by the second magnetic field enhancing component 822 provided by the embodiment of the application has high image signal to noise ratio, clear and fine image and no introduced artifact. Thus, the second cylindrical magnetic field enhancer 820 constructed of a plurality of the second magnetic field enhancing members 822 has a better sequence versatility.

In one embodiment, one end of the first switch control circuit 430 is connected to a portion where the first electrode layer 110 and the second electrode layer 120 overlap in the orthographic projection of the first dielectric layer 100. The other end of the first switch control circuit 430 is connected to a portion where the second electrode layer 120 and the first electrode layer 110 overlap in the front projection of the first dielectric layer 100. That is, the first switch control circuit 430 can be connected to the first electrode layer 110 at a position that constitutes the first structure capacitor 150. It is thus possible to avoid that the first switch control circuit 430 is connected to a portion of the first electrode layer 110 that does not constitute the second structural capacitance 152 and the third structural capacitance 153. Thereby avoiding the influence on the portion of the first electrode layer 110 constituting the equivalent inductance.

Referring to fig. 24, in one embodiment, the second magnetic field enhancement component 822 further includes a first external capacitor 440. Both ends of the first external capacitor 440 are respectively connected to the first electrode layer 110 and the second electrode layer 120. The first external capacitor 440 may be a tunable capacitor connected in parallel with the first electrode layer 110 and the second electrode layer 120. When the usage of the second magnetic field enhancement component 822 is fixed, for example, the resonant frequency of the second cylindrical magnetic field enhancer 820 formed by a plurality of the second magnetic field enhancement components 822 is determined, the first external capacitor 440 may be a fixed capacitor. It is understood that the fixed capacitance or the adjustable capacitance of the first external capacitor 440 is within the protection range.

The resonance performance of the second cylindrical magnetic field enhancer 820 formed by the plurality of second magnetic field enhancing members 822 can be adjusted by the capacitive coupling of the first external capacitor 440 with the structure formed by the first electrode layer 110, the second electrode layer and the first dielectric layer 100.

Referring to fig. 25, in one embodiment, the first switch control circuit 430 includes a first diode 431 and a second diode 432. An anode of the first diode 431 is connected to the first electrode layer 110. The cathode of the first diode 431 is connected to the second electrode layer 120. The cathode of the second diode 432 is connected to the first electrode layer 110, and the anode of the second diode 432 is connected to the second electrode layer 120.

It is understood that the turn-on voltage of the first diode 431 and the second diode 432 may be between 0 volt and 1 volt. In one embodiment, the turn-on voltage of the first diode 431 and the second diode 432 may be 0.8V. The first diode 431 and the second diode 432 are respectively connected in series between the first electrode layer 110 and the second electrode layer, and the first diode 431 and the second diode 432 are reversely connected.

Due to the alternating nature of radio frequency. The induced voltage generated by the first electrode layer 110 and the second electrode layer 120 is also an alternating voltage. In the radio frequency emission phase, the turn-on voltage of the first diode 431 and the second diode 432 has been exceeded due to the voltage difference between the first electrode layer 110 and the second electrode layer 120. Therefore, whichever of the first electrode layer 110 and the second electrode layer 120 has a higher voltage, one of the first diode 431 and the second diode 432 is always in an on state. Thus electrically connecting the first electrode layer 110 and the second electrode layer.

And in the rf receiving stage, since the voltage difference between the first electrode layer 110 and the second electrode layer is smaller than the turn-on voltage of the first diode 431 and the second diode 432. Therefore, the first diode 431 and the second diode 432 are in a non-conductive state regardless of which of the first electrode layer 110 and the second electrode layer 120 is high in voltage.

Referring to fig. 26, in one embodiment, the first switch control circuit 430 further includes a first enhancement MOS transistor 433 and a second enhancement MOS transistor 434. The source electrode of the first enhancement MOS transistor 433 is connected to the second electrode layer. The drain electrode of the first enhancement MOS transistor 433 is connected to the first electrode layer 110. The gate of the first enhancement MOS transistor 433 is connected to the first electrode layer 110. The source of the second enhancement MOS transistor 434 is connected to the first electrode layer 110. The drain of the second enhancement MOS transistor 434 is connected to the second electrode layer 120. The gate of the second enhancement MOS transistor 434 is connected to the second electrode layer 120. Namely, the first enhancement type MOS tube 433 and the second enhancement type MOS tube 434 are reversely connected.

The first enhancement MOS transistor 433 and the second enhancement MOS transistor 434 are not turned on when the gate voltage is less than the threshold voltage, that is, a conductive channel can occur only when the magnitude of the gate voltage is greater than the threshold voltage thereof.

It will be appreciated that during the rf emission phase, since the voltage difference between the first electrode layer 110 and the second electrode layer 120 has exceeded the threshold voltage at which the first enhancement MOS transistor 433 and the second enhancement MOS transistor 434 are turned on, no matter which of the first electrode layer 110 and the second electrode layer is high, one of the first enhancement MOS transistor 433 and the second enhancement MOS transistor 434 is in an on state. Thus electrically connecting the first electrode layer 110 and the second electrode layer.

In the rf receiving stage, the voltage difference between the first electrode layer 110 and the second electrode layer is smaller than the on threshold voltage of the first enhancement MOS transistor 433 and the second enhancement MOS transistor 434. Therefore, regardless of which of the first electrode layer 110 and the second electrode layer 120 has a high voltage, the first enhancement MOS transistor 433 and the second enhancement MOS transistor 434 are in a non-conductive state.

Referring to fig. 27, in one embodiment, the second magnetic field enhancement component 822 further includes a second external capacitor 442, the third external capacitor 443, and a second switch control circuit 450. The second external capacitor 442 and the third external capacitor 443 are connected in series between the first electrode layer 110 and the second electrode layer 120. One end of the second switch control circuit 450 is connected to the first electrode layer 110, the other end of the second switch control circuit 450 is connected between the second external capacitor 442 and the third external capacitor 443, and the second switch control circuit 450 is configured to be turned on in a radio frequency transmitting stage and turned off in a radio frequency receiving stage.

The second external capacitor 442 and the third external capacitor 443 may be fixed capacitors or tunable capacitors. When the resonant frequency of the loop in which the second magnetic field enhancement component 822 is located is determined, a suitable fixed capacitance may be selected as the second external capacitance 442 and the third external capacitance 443. When the resonant frequency of the loop in which the second magnetic field enhancement component 822 is located is required to be adjusted as required, the second external capacitor 442 and the third external capacitor 443 can be adjustable capacitors.

It will be appreciated that the radio frequency transmit phase and the radio frequency receive phase differ in time sequence by tens to thousands of milliseconds. The radio frequency power of the radio frequency transmit phase and the radio frequency receive phase differ by 3 orders of magnitude. The voltage on the structure capacitance during the rf transmission phase is between a few volts and a few hundred volts. And during the radio frequency receiving phase, the voltage across the structural capacitance is in the millivolt level.

One end of the second switch control circuit 450 is connected to the first electrode layer 110, and the other end of the second switch control circuit 450 is connected between the second external capacitor 442 and the third external capacitor 443. Therefore, when the second switch control circuit 450 is turned on, the second external capacitor 442 is shorted. Only the third external capacitor 443 is connected between the first electrode layer 110 and the second electrode layer 120. When the second switch control circuit 450 is turned off, the second external capacitor 442 and the third external capacitor 443 are connected in series between the first electrode layer 110 and the second electrode layer 120.

The turn-on voltage of the second switch control circuit 450 may be greater than 1 volt. That is, when the voltage difference between the first electrode layer 110 and the second electrode layer is greater than 1 volt, the second switch control circuit 450 is turned on. The second switch control circuit 450 is turned off when the voltage difference between the first electrode layer 110 and the second electrode layer 120 is less than 1 volt.

During the rf transmission phase, the second switch control circuit 450 is turned on due to the large voltage difference across the structure capacitance. The second external capacitor 442 is shorted. Only the third external capacitor 443 is connected between the first electrode layer 110 and the second electrode layer 120. The degree of detuning of the loop in which the second magnetic field enhancement component 822 is located during the rf transmission phase can be adjusted by adjusting the third external capacitance 443. I.e. the degree of detuning of the loop in which the second magnetic field enhancement component 822 is located during the rf transmission phase, can be adjusted by the third external capacitor 443. At this time, the third external capacitor 443 is connected to the circuit, and the equivalent capacitance is larger, and the resonant frequency is low.

The third external capacitor 443 can accurately adjust the resonant frequency of the second cylindrical magnetic field enhancer 820 formed by the plurality of second magnetic field enhancing components 822, so that the original magnetic field intensity of the detected region is maintained, the interference of the second magnetic field enhancing components 822 on the radio frequency emission stage is eliminated, the clinical practicability of the second cylindrical magnetic field enhancer 820 formed by the plurality of second magnetic field enhancing components 822 can be effectively improved, and the second cylindrical magnetic field enhancer 820 is applicable to all sequences of a magnetic resonance system.

And during the rf receiving phase, the voltage difference across the structural capacitor is small, and the second switch control circuit 450 is turned off. The second external capacitor 442 and the third external capacitor 443 are connected in series between the first electrode layer 110 and the second electrode layer 120. At this time, the equivalent capacitance of the second external capacitor 442 and the third external capacitor 443 is small, and the loop resonant frequency of the second magnetic field enhancement component 822 is high.

Referring to fig. 28, the loop in which the second magnetic field enhancement component 822 is located can have a good resonant frequency in the rf receiving stage by adjusting the second external capacitor 442 and the third external capacitor 443. Eventually, the resonant frequency of the loop in which the second magnetic field enhancement component 822 is located reaches the operating frequency of the MRI system during the receive phase. The second magnetic field enhancement component 822 has a nonlinear response characteristic. The second magnetic field enhancement component 822 can provide enhancement to the radio frequency transmit field.

Referring to fig. 29, in one embodiment, the second switch control circuit 450 includes a third diode 451 and a fourth diode 452. An anode of the third diode 451 is connected to the first electrode layer 110, and a cathode of the third diode 451 is connected between the second external capacitor 442 and the third external capacitor 443. The anode of the fourth diode 452 is connected between the second external capacitor 442 and the third external capacitor 443. The cathode of the fourth diode 452 is connected to the first electrode layer 110.

It is understood that the turn-on voltage of the third diode 451 and the fourth diode 452 may be between 0 volts and 1 volt. In one embodiment, the turn-on voltage of the third diode 451 and the fourth diode 452 may be 0.8V. The third diode 451 and the fourth diode 452 are respectively connected in series between the first electrode layer 110 and the second electrode layer, i.e., the third diode 451 and the fourth diode 452 are reversely connected.

Due to the alternating nature of radio frequency. The induced voltage generated by the first electrode layer 110 and the second electrode layer 120 is also an alternating voltage. In the radio frequency emission phase, the turn-on voltage of the third diode 451 and the fourth diode 452 has been exceeded due to the voltage difference between the first electrode layer 110 and the second electrode layer 120. Therefore, whichever of the first electrode layer 110 and the second electrode layer 120 has a high voltage, one of the third diode 451 and the fourth diode 452 is always in an on state. The second external capacitor 442 is shorted.

And in the rf receiving stage, since the voltage difference between the first electrode layer 110 and the second electrode layer is smaller than the turn-on voltage of the third diode 451 and the fourth diode 452. Therefore, no matter which of the first electrode layer 110 and the second electrode layer 120 has a high voltage, the third diode 451 and the fourth diode 452 are in a non-conductive state, and the second external capacitor 442 and the third external capacitor 443 are connected in series between the first electrode layer 110 and the second electrode layer 120.

Referring to fig. 30, in one embodiment, the second switch control circuit 450 further includes a third enhancement MOS transistor 453 and a fourth enhancement MOS transistor 454. The source of the third enhancement MOS tube 453 is connected between the second external capacitor 442 and the third external capacitor 443. The drain electrode of the third enhancement MOS transistor 453 is connected to the first electrode layer 110. The gate 453 of the third enhancement MOS transistor is connected to the first electrode layer 110. The source of the fourth enhancement MOS transistor 454 is connected to the first electrode layer 110. The drain of the fourth enhancement MOS transistor 454 is connected between the second external capacitor 442 and the third external capacitor 443. The gate of the fourth enhancement MOS transistor 454 is connected between the second external capacitor 442 and the third external capacitor 443. Namely, the third enhancement MOS tube 453 and the fourth enhancement MOS tube 454 are reversely connected.

The third enhancement MOS transistor 453 and the fourth enhancement MOS transistor 454 are not turned on when the gate voltage is smaller than the threshold voltage, that is, a conductive channel can occur only when the magnitude of the gate voltage is larger than the threshold voltage thereof.

It will be appreciated that during the rf emission phase, since the voltage difference between the first electrode layer 110 and the second electrode layer 120 has exceeded the threshold voltage at which the third enhancement MOS transistor 453 and the fourth enhancement MOS transistor 454 are turned on, no matter which of the first electrode layer 110 and the second electrode layer is high, one of the third enhancement MOS transistor 453 and the fourth enhancement MOS transistor 454 is in an on state. The second external capacitor 442 is shorted.

In the rf receiving stage, the voltage difference between the first electrode layer 110 and the second electrode layer is smaller than the on threshold voltage of the third enhancement MOS transistor 453 and the fourth enhancement MOS transistor 454. Therefore, the third enhancement MOS transistor 453 and the fourth enhancement MOS transistor 454 are in a non-conductive state no matter which of the first electrode layer 110 and the second electrode layer 120 is high in voltage. At this time, the second external capacitor 442 and the third external capacitor 443 are connected in series between the first electrode layer 110 and the second electrode layer 120.

The second switch control circuit 450 is turned off during the rf receiving phase, and the first electrode layer 110 and the fourth electrode layer 140 can form the third structural capacitor 153. The third structural capacitor 153 and the second structural capacitor 152 cooperate to further enhance the magnetic field enhancement effect.

In one embodiment, one end of the second switch control circuit 450 is connected to a position where the first electrode layer 110 and the second electrode layer 120 have overlapping portions in the orthographic projection of the first dielectric layer 100. The other end of the second switch control circuit 450 is connected to a position where the second electrode layer 120 and the first electrode layer 110 have a superposition portion in the front projection of the first dielectric layer 100. That is, the second switch control circuit 450 can be connected to the first electrode layer 110 at a position that constitutes the second structure capacitor 152. It is therefore possible to avoid that the second switch control circuit 450 is connected to a portion of the first electrode layer 110 that does not constitute the second structural capacitance 152 and the third structural capacitance 153. Thereby avoiding the influence on the portion of the first electrode layer 110 constituting the equivalent inductance.

Referring to fig. 31, in one embodiment, the second magnetic field enhancement component 822 further includes a fourth external capacitor 444, a fifth external capacitor 445, and a third switch control circuit 460. The orthographic projection of the first electrode layer 110 on the first dielectric layer 100 and the orthographic projection of the second electrode layer 120 on the first dielectric layer 100 are overlapped to form a first structural capacitor 150. Both ends of the fourth external capacitor 444 are connected between the first electrode layer 110 and the second electrode layer 120. The fifth external capacitor 445 and the third switch control circuit 460 are connected in series between the first electrode layer 110 and the second electrode layer 120, and the third switch control circuit 460 is configured to be turned on during a radio frequency transmitting phase and turned off during a radio frequency receiving phase.

The second external capacitor 442 and the fifth external capacitor 445 may be fixed capacitors or tunable capacitors. When the resonant frequency of the loop in which the second magnetic field enhancement component 822 is located is determined, a suitable fixed capacitance may be selected as the second external capacitance 442 and the fifth external capacitance 445. The second external capacitor 442 and the fifth external capacitor 445 may be tunable capacitors when the resonant frequency of the loop in which the second magnetic field enhancing component 822 is located is required to be adjusted as required.

And the third external capacitor 443 may be a fixed capacitor or an adjustable capacitor. When the resonant frequency of the loop in which the second magnetic field enhancement component 822 is located is determined, a suitable fixed capacitance may be selected as the second external capacitance 442 and the third external capacitance 443. When the resonant frequency of the loop in which the second magnetic field enhancement component 822 is located is required to be adjusted as required, the second external capacitor 442 and the third external capacitor 443 can be adjustable capacitors.

The third switch control circuit 460 and the fifth external capacitor 445 are connected in series between the first electrode layer 110 and the second electrode layer 120. Therefore, when the third switch control circuit 460 is turned on, the fifth external capacitor 445 and the fourth external capacitor 444 are connected in parallel to the first electrode layer 110 and the second electrode layer 120. When the total capacitance of the second magnetic field enhancement component 822 is equal, the capacitance of the fifth external capacitor 445 and the fourth external capacitor 444 connected in parallel is larger than the series connection of the two capacitors, so that the capacitance of the first structure capacitor 150 can be smaller, and the second magnetic field enhancement component 822 has lower loss.

In the rf transmission stage, the resonant frequency of the loop in which the second magnetic field enhancing component 822 is located deviates from the working frequency of the magnetic resonance system, so that by adjusting the fifth external capacitor 445 and the fourth external capacitor 444, it can be ensured that the magnetic field strength of the second magnetic field enhancing component 822 is the same in the rf transmission stage of the magnetic resonance system.

In the emission phase, the voltage difference between the first electrode layer 110 and the second electrode layer 120 is large, and the third switch control circuit 460 is turned on. The fourth external capacitor 444 and the fifth external capacitor 445 are connected in series between the first electrode layer 110 and the second electrode layer 120.

And during the rf receiving phase, the voltage difference between the first electrode layer 110 and the second electrode layer 120 is small, and the third switch control circuit 460 is turned off. Only the fourth external capacitor 444 is connected in series between the first electrode layer 110 and the second electrode layer 120. By adjusting the fourth external capacitor 444, the resonant frequency of the loop where the second magnetic field enhancement component 822 is located can be adjusted, so that the resonant frequency is equal to the frequency of the radio frequency coil, thereby greatly enhancing the radio frequency receiving field and improving the signal-to-noise ratio of the image.

Referring to fig. 32, by adjusting the fourth external capacitor 444 and the fifth external capacitor 445, the second cylindrical magnetic field enhancer 820 formed by the plurality of second magnetic field enhancing components 822 can have a good resonant frequency in the rf receiving stage. Eventually, the resonance frequency of the second cylindrical magnetic field enhancer 820 formed by the plurality of second magnetic field enhancing assemblies 822 reaches the operating frequency of the magnetic resonance system in the receiving stage.

Referring to fig. 33, in one embodiment, the second magnetic field enhancing component 822 includes a fifth diode 461 and a sixth diode 462. An anode of the fifth diode 461 is connected to the first electrode layer 110. The cathode of the fifth diode 461 is connected to one end of the fifth external capacitor 445. An anode of the sixth diode 462 is connected to one end of the fifth external capacitor 445. The cathode of the sixth diode 462 is connected to the first electrode layer 110.

It is understood that the turn-on voltage of the fifth diode 461 and the sixth diode 462 may be between 0 volts and 1 volt. In one embodiment, the turn-on voltage of the fifth diode 461 and the sixth diode 462 may be 0.8V. The fifth diode 461 and the sixth diode 462 are respectively connected in series between the first electrode layer 110 and the second electrode layer, i.e., the fifth diode 461 and the sixth diode 462 are reversely connected.

Due to the alternating nature of radio frequency. The induced voltage generated by the first electrode layer 110 and the second electrode layer 120 is also an alternating voltage. In the radio frequency emission phase, the turn-on voltage of the fifth diode 461 and the sixth diode 462 has been exceeded due to the voltage difference between the first electrode layer 110 and the second electrode layer 120. Therefore, whichever of the first electrode layer 110 and the second electrode layer 120 has a higher voltage, one of the fifth diode 461 and the sixth diode 462 is always in an on state. The fourth external capacitor 444 and the fifth external capacitor 445 are thus connected in parallel between the first electrode layer 110 and the second electrode layer 120.

And in the rf receiving stage, since the voltage difference between the first electrode layer 110 and the second electrode layer is smaller than the turn-on voltage of the fifth diode 461 and the sixth diode 462. Therefore, no matter which of the first electrode layer 110 and the second electrode layer 120 has a high voltage, the fifth diode 461 and the sixth diode 462 are in a non-conductive state, and only the fourth external capacitor 444 is connected between the first electrode layer 110 and the second electrode layer 120.

Referring to fig. 34, in one embodiment, the third switch control circuit 460 further includes a fifth enhancement MOS transistor 463 and a sixth enhancement MOS transistor 464. The source of the fifth enhancement MOS tube 463 is connected to one end of the fifth external capacitor 445. The drain electrode of the fifth enhancement MOS transistor 463 is connected to the first electrode layer 110. The gate of the fifth enhancement MOS transistor 463 is connected to the first electrode layer 110. The source of the sixth enhancement MOS transistor 464 is connected to the first electrode layer 110. The drain electrode of the sixth enhancement MOS transistor 464 is connected to one end of the fifth external capacitor 445. The gate of the sixth enhancement MOS transistor 464 is connected to one end of the fifth external capacitor 445. Namely the fifth enhancement type MOS tube 463 and the sixth enhancement type MOS tube 464 are reversely connected.

It will be appreciated that the fifth enhancement MOS 463 and the sixth enhancement MOS 464 are non-conductive when the gate voltage is less than the threshold voltage, i.e. a conductive channel is only present when the magnitude of the gate voltage is greater than its threshold voltage.

In the rf emission phase, since the voltage difference between the first electrode layer 110 and the second electrode layer 120 exceeds the threshold voltage at which the fifth enhancement MOS transistor 463 and the sixth enhancement MOS transistor 464 are turned on, no matter which of the first electrode layer 110 and the second electrode layer 120 is high, one of the fifth enhancement MOS transistor 463 and the sixth enhancement MOS transistor 464 is in the on state. The fourth external capacitor 444 and the fifth external capacitor 445 are thus connected in parallel between the first electrode layer 110 and the second electrode layer 120.

In the rf receiving stage, the voltage difference between the first electrode layer 110 and the second electrode layer is smaller than the on threshold voltage of the fifth enhancement MOS transistor 463 and the sixth enhancement MOS transistor 464. Therefore, whichever of the first electrode layer 110 and the second electrode layer 120 has a higher voltage, the fifth enhancement MOS transistor 463 and the sixth enhancement MOS transistor 464 are in a non-conductive state. The fourth external capacitor 444 is connected between the first electrode layer 110 and the second electrode layer 120.

In one embodiment, one end of the third switch control circuit 460 is connected to a position where the first electrode layer 110 and the second electrode layer 120 have overlapping portions in the orthographic projection of the first dielectric layer 100. The other end of the third switch control circuit 460 is connected to a position where the second electrode layer 120 and the first electrode layer 110 have a superposition portion in the front projection of the first dielectric layer 100. That is, the third switch control circuit 460 can be connected to the first electrode layer 110 at a position that is a part of the second structure capacitor 152. It is therefore possible to avoid the third switch control circuit 460 from being connected to a portion of the first electrode layer 110 that does not constitute the second structural capacitance 152 and the third structural capacitance 153. Thereby avoiding the influence on the portion of the first electrode layer 110 constituting the equivalent inductance.

Referring to fig. 35, in one embodiment, the first magnetic field enhancement component 812 includes a second dielectric layer 831, a seventh electrode layer 832, an eighth electrode layer 833, and a ninth electrode layer 834. The second dielectric layer 831 has a third surface 805 and a fourth surface 806 disposed opposite to each other. The second dielectric layer 831 has a third end 881 and a fourth end 882 disposed opposite thereto. The seventh electrode layer 832 is disposed on the third surface 805. The seventh electrode layer 832 covers the third surface 805. That is, the seventh electrode layer 832 entirely covers the third surface 805. The eighth electrode layer 833 is disposed on the fourth surface 806. The eighth electrode layer 833 covers a portion of the fourth surface 806. The eighth electrode layer 833 is disposed adjacent to the third end 881. The ninth electrode layer 834 and the eighth electrode layer 833 are disposed on the fourth surface 806 at intervals. The ninth electrode layer 834 covers a portion of the fourth surface 806. The ninth electrode layer 834 is disposed proximate the fourth end 882.

The eighth electrode layer 833 is disposed on the second dielectric layer 831 in front projection, and the seventh electrode layer 832 is disposed on the second dielectric layer 831 in front projection, thereby forming a sixth structure capacitor 807. That is, the orthographic projection of the eighth electrode layer 833 on the second dielectric layer 831 and a portion of the orthographic projection of the seventh electrode layer 832 on the second dielectric layer 831 overlap. In the overlapping portion, the eighth electrode layer 833, the second dielectric layer 831, and the seventh electrode layer 832 form the sixth structural capacitor 807.

The ninth electrode layer 834 is in front projection of the second dielectric layer 831, and is located in front projection of the seventh electrode layer 832 in the second dielectric layer 831, forming a seventh structural capacitance 808. That is, the orthographic projection of the ninth electrode layer 834 on the second dielectric layer 831 and a portion of the orthographic projection of the seventh electrode layer 832 on the second dielectric layer 831 overlap. In the overlapping portion, the ninth electrode layer 834, the second dielectric layer 831, and the seventh electrode layer 832 form the seventh structural capacitor 808.

The seventh electrode layer 832 between the sixth structural capacitance 807 and the seventh structural capacitance 808 forms a transmission line, connecting the sixth structural capacitance 807 and the seventh structural capacitance 808 in series. The sixth structural capacitor 807 and the seventh structural capacitor 808 are disposed at both ends of the second dielectric layer 831. And, the first external capacitor 405 in the second magnetic field enhancement component 822 is disposed near the middle of the first dielectric layer 100. The binuclear magnetic field enhancing means 30 has capacitances formed at both ends and the middle portion, respectively.

The structural capacitance of the first magnetic field enhancement component 812 in the first cylindrical magnetic field enhancer 810 is disposed at both ends. The capacitance of the second magnetic field enhancing assembly 822 in the second cylindrical magnetic field enhancer 820 is disposed in an intermediate position. When the second cylindrical magnetic field enhancer 820 is nested with the first cylindrical magnetic field enhancer 810, the capacitance is uniformly distributed in the middle and at both ends. The capacitance is uniformly distributed in the middle and both ends so that the electric field is mainly distributed in the middle and both ends, reducing the electrical coupling between the second cylindrical magnetic field enhancer 820 and the first cylindrical magnetic field enhancer 810. The electric coupling between the second cylindrical magnetic field enhancer 820 and the first cylindrical magnetic field enhancer 810 is reduced, which is beneficial to realizing simultaneous enhancement of two signal fields of dual-core MRI, further improves the magnetic field enhancing effect of the dual-core magnetic field enhancing device 30, and is more beneficial to imaging of MRI equipment.

Referring to fig. 36, in one embodiment, the width of the seventh electrode layer 832 between the sixth structural capacitor 807 and the seventh structural capacitor 808 is smaller than the width of the seventh electrode layer 832 corresponding to the sixth structural capacitor 807 and the seventh structural capacitor 808 in a direction around the central axis of the first cylindrical holder 811.

In this embodiment, the seventh electrode layer 832 between the sixth structural capacitor 807 and the seventh structural capacitor 808 forms a transmission line, and connects the sixth structural capacitor 807 and the seventh structural capacitor 808. However, the opposite arrangement between the electrode layers corresponding to the transmission line may form a stray capacitance. The width of the seventh electrode layer 832 between the sixth structural capacitor 807 and the seventh structural capacitor 808 is smaller than the width of the seventh electrode layer 832 corresponding to the sixth structural capacitor 807 and the seventh structural capacitor 808, so that the width of the transmission line becomes smaller, and the relative area between the electrode layers becomes smaller.

Therefore, the width of the transmission line becomes smaller, reducing the stray capacitance formed. Therefore, without affecting the connection between the sixth structural capacitor 807 and the seventh structural capacitor 808, stray capacitance is reduced, which is more beneficial to the uniform distribution of magnetic field, and improves MRI image quality.

Since the width of the first electrode layer 110, the width of the second electrode layer 120, and the width of the seventh electrode layer 832 between the sixth structural capacitor 807 and the seventh structural capacitor 808 are all smaller, the relative area between the transmission line electrodes is smaller, and the stray capacitance formed is reduced. The stray capacitance is reduced, the magnetic field is more favorably distributed uniformly, and the MRI image quality is improved.

In one embodiment, the first magnetic field enhancement component 812 is offset from the second magnetic field enhancement component 822. That is, the first magnetic field enhancement component 812 and the second magnetic field enhancement component 822 are not disposed opposite to each other, but are spaced apart from each other. For example, one of the second magnetic field enhancement assemblies 822 is disposed in a spaced relationship between two of the first magnetic field enhancement assemblies 812. Stray capacitance is not formed between the transmission line electrode of the first magnetic field enhancement component 812 and the transmission line electrode of the second magnetic field enhancement component 822, which is beneficial to realizing simultaneous enhancement of two signal fields of dual-core MRI, further improving the magnetic field enhancement effect of the dual-core magnetic field enhancement device 30, and being more beneficial to imaging of MRI equipment.

Referring to fig. 37 and 38, in one embodiment, the first magnetic field enhancement device 812 includes a second dielectric layer 831, a seventh electrode layer 832, an eighth electrode layer 833, a ninth electrode layer 834, and a tenth electrode layer 835. The second dielectric layer 831 has a third surface 805 and a fourth surface 806 disposed opposite to each other. The second dielectric layer 831 has a third end 881 and a fourth end 882 disposed opposite thereto. The seventh electrode layer 832 is disposed on the third surface 805. The seventh electrode layer 832 is disposed proximate the fourth end 882. The seventh electrode layer 832 covers a portion of the third surface 805. The eighth electrode layer 833 is disposed on the fourth surface 806 and covers a portion of the fourth surface 806. The eighth electrode layer 833 is disposed adjacent to the third end 881. The ninth electrode layer 834 and the eighth electrode layer 833 are disposed on the fourth surface 806 at intervals. The ninth electrode layer 834 covers a portion of the fourth surface 806. The ninth electrode layer 834 is disposed proximate the fourth end 882.

The orthographic projection of the eighth electrode layer 833 onto the second dielectric layer 831 characterizes the structural size and shape of the eighth electrode layer 833. The orthographic projection of the seventh electrode layer 832 on the second dielectric layer 831 characterizes the structural size and shape of the seventh electrode layer 832. The front projection of the seventh electrode layer 832 on the second dielectric layer 831 and the front projection of the eighth electrode layer 833 on the second dielectric layer 831 overlap to form a ninth structure capacitance 809 of the ninth structure capacitance 809. That is, the eighth electrode layer 833 and the seventh electrode layer 832 are disposed opposite to each other on both surfaces of the second dielectric layer 831, and have overlapping portions. At the overlapping portion, the eighth electrode layer 833, the second dielectric layer 831, and the seventh electrode layer 832 form the ninth structural capacitor 809.

The orthographic projection of the ninth electrode layer 834 onto the second dielectric layer 831 characterizes the structural size and shape of the ninth electrode layer 834. The ninth electrode layer 834 is in front projection of the second dielectric layer 831, and is located in front projection of the seventh electrode layer 832 in the second dielectric layer 831, forming a seventh structural capacitance 808. That is, the orthographic projection of the ninth electrode layer 834 on the second dielectric layer 831 and the orthographic projection of the seventh electrode layer 832 on the second dielectric layer 831 partially overlap. At the overlapping portion, the ninth electrode layer 834, the second dielectric layer 831, and the seventh electrode layer 832 form the seventh structural capacitor 808.

The tenth electrode layer 835 is disposed on the third surface 805 at a distance from the seventh electrode layer 832. The tenth electrode layer 835 covers a portion of the third surface 805. The orthographic projection of the tenth electrode layer 835 on the second dielectric layer 831 characterizes the structural size and shape of the tenth electrode layer 835.

The orthographic projection of the tenth electrode layer 835 on the second dielectric layer 831 is located in the projection of the eighth electrode layer 833 on the second dielectric layer 831, forming a sixth structural capacitance 807. That is, the orthographic projection of the tenth electrode layer 835 on the second dielectric layer 831 and the orthographic projection of the eighth electrode layer 833 on the second dielectric layer 831 partially overlap. At the overlapping portion, the tenth electrode layer 835, the second dielectric layer 831, and the eighth electrode layer 833 form the sixth structural capacitor 807.

The tenth electrode layer 835 and the seventh electrode layer 832 are respectively disposed at both ends of the eighth electrode layer 833. At this time, both ends of the eighth electrode layer 833 form the sixth structural capacitance 807 and the ninth structural capacitance 809 and a ninth structural capacitance 809 with the tenth electrode layer 835 and the seventh electrode layer 832, respectively. The portion between the two ends of the eighth electrode layer 833 forms a transmission line. The sixth structural capacitor 807 and the ninth structural capacitor 809 are connected in series through a transmission line, forming a structure in which both capacitors are connected in series. Thus, by the first magnetic field enhancement component 812 of the present application, a structure is formed in which three capacitors of the sixth structural capacitor 807, the ninth structural capacitor 809, and the seventh structural capacitor 808 are connected in series.

The sixth structural capacitance 807, the ninth structural capacitance 809, and the seventh structural capacitance 808 cooperate with each other such that the enhancement device formed by the first magnetic field enhancing component 812 reaches an optimal resonant frequency during the radio frequency receive phase of the MRI system. When the working frequency of the enhancement device formed by the first magnetic field enhancement component 812 is the same as that of the MRI equipment, the magnetic field of the detection part can be enhanced, and the magnetic field enhancement function is achieved.

Under the condition of ensuring that the resonance frequency is the same, the sixth structural capacitor 807, the ninth structural capacitor 809 and the seventh structural capacitor 808 are connected in series, so that the sixth structural capacitor 807, the ninth structural capacitor 809 and the seventh structural capacitor 808 adopt capacitors with larger capacitance values and are suitable for high-frequency MRI equipment. The sixth structural capacitor 807, the ninth structural capacitor 809, and the seventh structural capacitor 808 use capacitors having larger capacitance values, and can avoid using small capacitors. The capacitor with a large capacitance value can enable the fluctuation of the resonance frequency to be small, improves the stability of the resonance frequency, and is more suitable for high-field MRI equipment.

The first magnetic field enhancement component 812 generates an induced voltage in a magnetic field environment. The eighth electrode layer 833 between the sixth structure capacitance 807 and the ninth structure capacitance 809 forms a first transmission line. The seventh electrode layer 832 between the seventh structure capacitance 808 and the ninth structure capacitance 809 forms a second transmission line. When the plurality of first magnetic field enhancement components 812 form an enhancement device, the first transmission line and the second transmission line may form parasitic capacitances. The parasitic capacitance is in parallel relation with the sixth structure capacitance 807, the ninth structure capacitance 809 and the seventh structure capacitance 808, respectively. The sixth configuration capacitor 807, the ninth configuration capacitor 809, and the seventh configuration capacitor 808 are connected in series, and the induced voltage can be divided into a plurality of values, reducing the divided voltages of the sixth configuration capacitor 807, the ninth configuration capacitor 809, and the seventh configuration capacitor 808.

Further, the sixth structure capacitor 807, the ninth structure capacitor 809, and the seventh structure capacitor 808 form a series structure, reducing the voltage on the parasitic capacitance. The voltage on the parasitic capacitance is reduced, and the harm of the parasitic capacitance is reduced, so that the load effect is reduced. When the plurality of first magnetic field enhancement components 812 form the enhancement device and load is applied, the resonance frequency does not deviate greatly, so that the load effect of the first magnetic field enhancement components 812 is reduced, and the resonance frequency is not easily affected by the object to be tested. The resonant frequency is not easily affected by the object under test, so that the enhancement performance of the first magnetic field enhancement component 812 can be improved, and the stability of the resonant frequency is enhanced.

In one embodiment, the materials of the seventh electrode layer 832, the eighth electrode layer 833, the ninth electrode layer 834 and the tenth electrode layer 835 may be nonmagnetic metals such as copper, silver, gold, etc. The material of the second dielectric layer 831 may be a material having a flame-retardant material grade of FR4, a high-temperature resistant thermoplastic resin such as polyphenylene oxide (PPE), a Rogers 4003C material, or the like.

In one embodiment, the second dielectric layer 831 has a width of 15mm, a thickness of 0.51mm, and a length of 250mm.

In one embodiment, the overlapping length of the electrode layers corresponding to the sixth structural capacitor 807, the ninth structural capacitor 809 and the seventh structural capacitor 808 in the direction from the third end 881 to the fourth end 882 is 30mm.

In one embodiment, the length of the seventh electrode layer 832 between the ninth structural capacitance 809 and the seventh structural capacitance 808 is the same as the length of the eighth electrode layer 833 between the ninth structural capacitance 809 and the sixth structural capacitance 807.

In this embodiment, the seventh structure capacitance 808 and the sixth structure capacitance 807 are symmetrical with respect to the ninth structure capacitance 809. The effective magnetic field is distributed between said seventh structural capacitance 808 and said ninth structural capacitance 809 and between said sixth structural capacitance 807 and said ninth structural capacitance 809. The region where the effective magnetic field is formed is used as a detection region, and the detection part is detected. At this point, the effective magnetic field between the seventh structural capacitance 808 and the ninth structural capacitance 809 forms a first detection zone. The effective magnetic field between the sixth structural capacitance 807 and the ninth structural capacitance 809 forms a second detection region.

The length of the seventh electrode layer 832 between the ninth structural capacitance 809 and the seventh structural capacitance 808 and the length of the eighth electrode layer 833 between the ninth structural capacitance 809 and the sixth structural capacitance 807 are the same, i.e. the first detection region is the same as the second detection region. That is, the sixth structural capacitance 807 and the seventh structural capacitance 808 are symmetrically disposed about the ninth structural capacitance 809. That is, the sixth structural capacitance 807 is disposed proximate the third terminal 881. The seventh structural capacitor 808 is disposed proximate the fourth terminal 882. The ninth capacitor 809 is disposed in the middle of the connection line between the third terminal 881 and the fourth terminal 882. The sixth structural capacitance 807 and the seventh structural capacitance 808 are symmetrically disposed about the ninth structural capacitance 809, forming a uniformly distributed and symmetric magnetic field that facilitates imaging of the MRI apparatus.

Referring to fig. 39, in one embodiment, the width of the seventh electrode layer 832 between the ninth structure capacitance 809 and the seventh structure capacitance 808 is smaller than the width of the second dielectric layer 831.

In this embodiment, a transmission line is formed between the seventh electrode layer 832 between the ninth structural capacitor 809 and the seventh structural capacitor 808, and the ninth structural capacitor 809 is connected to the seventh structural capacitor 808. However, stray capacitance may be formed between the electrode layers. The width of the seventh electrode layer 832 between the ninth structural capacitor 809 and the seventh structural capacitor 808 becomes smaller, which results in a smaller width of the transmission line. Stray capacitance is reduced without affecting the connection of the ninth structural capacitance 809 to the seventh structural capacitance 808.

Referring to fig. 40, in one embodiment, the width of the eighth electrode layer 833 between the ninth structure capacitance 809 and the sixth structure capacitance 807 is smaller than the width of the second dielectric layer 831.

In this embodiment, the eighth electrode layer 833 between the ninth structure capacitor 809 and the sixth structure capacitor 807 forms a transmission line, and connects the ninth structure capacitor 809 and the sixth structure capacitor 807. However, stray capacitance may be formed between the electrode layers. The width of the eighth electrode layer 833 between the ninth structural capacitance 809 and the sixth structural capacitance 807 becomes smaller, which results in a smaller width of the transmission line. Stray capacitance is reduced without affecting the connection of the ninth structural capacitance 809 to the sixth structural capacitance 807.

In one embodiment, the width of the seventh electrode layer 832 between the ninth structural capacitance 809 and the seventh structural capacitance 808 is smaller than the width of the seventh electrode layer 832 corresponding to the ninth structural capacitance 809 in a direction perpendicular to the third end 881 to the fourth end 882. The width of the eighth electrode layer 833 between the ninth structural capacitance 809 and the sixth structural capacitance 807 is smaller than the width of the seventh electrode layer 832 corresponding to the ninth structural capacitance 809. The seventh electrode layer 832 corresponding to the ninth structure capacitor 809 has a larger width than the electrode layer between the capacitor structures, which is beneficial to form an effective facing area with the second electrode 120, thereby forming the ninth structure capacitor 809.

The width of the seventh electrode layer 832 between the ninth structural capacitor 809 and the seventh structural capacitor 808 is small, and the width of the eighth electrode layer 833 between the ninth structural capacitor 809 and the sixth structural capacitor 807 is small, so that stray capacitance is reduced without affecting the connection of the ninth structural capacitor 809 and the seventh structural capacitor 808, and imaging quality of the MRI apparatus is further improved.

Referring to fig. 41, in one embodiment, the seventh electrode layer 832 includes the first layer 111 and the second layer 112. The first layer 111 is spaced apart from the second layer 112. The second layer 112 is disposed adjacent the fourth end 882. The first layer 111 is disposed adjacent to the second layer 112.

The orthographic projection of the first layer 111 on the second dielectric layer 831 overlaps the orthographic projection of the eighth electrode layer 833 on the second dielectric layer 831 to form the ninth structure capacitor 809. The ninth electrode layer 834 is located in front projection of the second dielectric layer 831 in front projection of the second layer 112 in the second dielectric layer 831, forming the seventh structural capacitance 808.

The first magnetic field enhancement component 812 further includes a first depletion MOS tube 231 and a second depletion MOS tube 232. The source electrode of the first depletion MOS tube 231 is connected to one end of the first layer 111 near the second layer 112, and the gate electrode and the drain electrode of the first depletion MOS tube 231 are connected. The gate and the drain of the second depletion MOS transistor 232 are connected, and are connected to the gate and the drain of the first depletion MOS transistor 231. The source of the second depletion MOS 232 is connected to the second layer 112.

The first depletion MOS tube 231 and the second depletion MOS tube 232 are connected in reverse series, so that the first layer 111 and the second layer 112 can be controlled to be disconnected in a radio frequency transmitting stage and connected in a radio frequency receiving stage.

The first depletion MOS tube 231 and the second depletion MOS tube 232 have the characteristics of low voltage conduction and high voltage cut-off. And, the pinch-off voltage of the first depletion MOS transistor 231 and the second depletion MOS transistor 232 at room temperature is about 1V, and the turn-off time and the recovery time are both in nanosecond order.

The radio frequency transmitting phase and the radio frequency receiving phase in the MRI apparatus have a difference of several tens of milliseconds to several thousands of milliseconds in time sequence, so that the first depletion type MOS tube 231 and the second depletion type MOS tube 232 can be rapidly turned on and off. The radio frequency power of the radio frequency transmit phase and the radio frequency receive phase differ by 3 orders of magnitude. The induced voltage in the coil during the radio frequency transmit phase is between a few V and a few hundred V, with specific values being dependent on the chosen sequence and flip angle.

The first depletion MOS tube 231 and the second depletion MOS tube 232 are connected in reverse series, so that the first layer 111 and the second layer 112 can be controlled to be disconnected in a radio frequency transmitting stage and connected in a radio frequency receiving stage. In the radio frequency emission stage, the first depletion type MOS tube 231 and the second depletion type MOS tube 232 are connected in reverse series, so that the device can be adapted to an alternating current environment in MRI equipment. Regardless of the variation, it is ensured that one of the first depletion MOS transistor 231 and the second depletion MOS transistor 232 is turned off, so that the first layer 111 and the second layer 112 are disconnected and not connected.

In the radio frequency emission stage, the induced voltage is larger, the first depletion MOS tube 231 and the second depletion MOS tube 232 are in an off state, the first cylindrical magnetic field enhancers 810 formed by the plurality of first magnetic field enhancing components 812 are in an off state, and a detuned state is presented. The absence of current in the first magnetic field strength member 812 does not create an induced magnetic field that would interfere with radio frequency, eliminating the effect of the first cylindrical magnetic field strength member 810 on the magnetic field during the radio frequency emission phase.

In the rf receiving stage, the first depletion MOS 231 is turned on with the second depletion MOS 232, so as to ensure that the first layer 111 and the second layer 112 are connected. The first cylindrical magnetic field enhancers 810 formed by the plurality of first magnetic field enhancing components 812 are in a connection state, and can be in a resonance state, so that a signal field is greatly enhanced, and an image signal-to-noise ratio is enhanced.

Therefore, the first depletion MOS tube 231 and the second depletion MOS tube 232 control the first layer 111 and the second layer 112 to be disconnected in the radio frequency transmitting stage and connected in the radio frequency receiving stage, so that the first magnetic field enhancement component 812 can only enhance the radio frequency receiving field, does not enhance the radio frequency transmitting field, and improves the signal to noise ratio of the image.

The first magnetic field enhancement component 812 introduces a nonlinear control structure through the first depletion MOS transistor 231 and the second depletion MOS transistor 232, so that the first cylindrical magnetic field enhancer 810 formed by the plurality of first magnetic field enhancement components 812 also has nonlinear response characteristics, and can be applied to all clinical sequences including fast spin echo sequences.

Referring to fig. 42, in one embodiment, the first magnetic field enhancement component 812 further includes a third diode 451, a fourth diode 452, a second external capacitor 442, and a third external capacitor 443. The anode of the third diode 451 is electrically connected to the seventh electrode layer 832 corresponding to the seventh structural capacitor 808. The cathode of the fourth diode 452 is electrically connected to the seventh electrode layer 832 corresponding to the seventh structural capacitor 808. One end of the third external capacitor 443 is electrically connected to the ninth electrode layer 834. The other end of the third external capacitor 443 is electrically connected to the cathode of the third diode 451, the anode of the fourth diode 452, and one end of the second external capacitor 442, respectively. The other end of the second external capacitor 442 is electrically connected to the seventh electrode layer 832 corresponding to the seventh structural capacitor 808.

The radio frequency transmit phase and the radio frequency receive phase differ in time sequence by tens to thousands of milliseconds. The radio frequency power of the radio frequency transmit phase and the radio frequency receive phase differ by 3 orders of magnitude. The voltage on the structure capacitance during the rf transmission phase is between a few volts and a few hundred volts. And during the radio frequency receiving phase, the voltage across the structural capacitance is in the millivolt level.

The turn-on voltage of the third diode 451 and the fourth diode 452 may be greater than 1 volt. That is, when the voltage difference across the seventh electrode layer 832 and the ninth electrode layer 834 is greater than 1 volt, the third diode 451 or the fourth diode 452 is turned on. When the voltage difference across the seventh electrode layer 832 and the ninth electrode layer 834 is less than 1 volt, the third diode 451 and the fourth diode 452 are turned off.

It is understood that the turn-on voltage of the third diode 451 and the fourth diode 452 may be between 0 volts and 1 volt. In one embodiment, the turn-on voltage of the third diode 451 and the fourth diode 452 may be 0.8V. The third diode 451 and the fourth diode 452 are connected in series between the seventh electrode layer 832 and the ninth electrode layer 834, respectively, i.e. the third diode 451 and the fourth diode 452 are connected in reverse.

Due to the alternating nature of radio frequency. The induced voltages generated by the seventh electrode layer 832 and the ninth electrode layer 834 are also ac voltages. In the radio frequency emission phase, the turn-on voltage of the third diode 451 and the fourth diode 452 has been exceeded due to the voltage difference between the seventh electrode layer 832 and the ninth electrode layer 834. Therefore, whichever of the seventh electrode layer 832 and the ninth electrode layer 834 has a higher voltage, one of the third diode 451 and the fourth diode 452 is always in an on state. The second external capacitor 442 is shorted. Only the third external capacitor 443 is connected between the seventh electrode layer 832 and the ninth electrode layer 834. The degree of detuning of the loop in which the first magnetic field enhancement component 812 is located during the rf transmission phase can be reduced or avoided by providing a suitable third external capacitor 443.

The third external capacitor 443 can make the magnetic field intensity of the detected region in the magnetic resonance system be the same when the first magnetic field enhancement component 812 is used and before the first magnetic field enhancement component 812 is used, so that the influence of the first cylindrical magnetic field enhancer 810 on the radio frequency emission stage can be eliminated, the first cylindrical magnetic field enhancer 810 can be suitable for all clinical sequences, and the clinical practicability of the first cylindrical magnetic field enhancer 810 is improved.

And in the rf receiving stage, since the voltage difference between the seventh electrode layer 832 and the ninth electrode layer 834 is smaller than the turn-on voltage of the third diode 451 and the fourth diode 452. Therefore, no matter which of the seventh electrode layer 832 and the ninth electrode layer 834 has a high voltage, the third diode 451 and the fourth diode 452 are in a non-conductive state, and the second external capacitor 442 and the third external capacitor 443 are connected in series between the seventh electrode layer 832 and the ninth electrode layer 834 during the radio frequency receiving stage.

Referring to fig. 43, in one embodiment, the seventh electrode layer 832 includes the first layer 111 and the second layer 112. The first layer 111 is spaced apart from the second layer 112. The second layer 112 is disposed adjacent the fourth end 882. The first layer 111 is disposed adjacent to the second layer 112.

The first magnetic field enhancement component 812 further includes a first inductor 241, a third diode 213, and a fourth diode 214. One end of the third capacitor 223 is connected to one end of the first layer 111 near the second layer 112. The other end of the third capacitor 223 is connected to an end of the second layer 112 remote from the fourth end 882. One end of the first inductor 241 is connected to one end of the first layer 111 near the second layer 112. The other end of the first inductor 241 is connected to the cathode of the third diode 213 and the anode of the fourth diode 214, respectively. The anode of the third diode 213 and the cathode of the fourth diode 214 are connected to one end of the fourth terminal 882 of the second layer 112.

In MRI systems, to enhance the magnetic field strength of human feedback signals during the radio frequency receive phase. In the radio frequency transmission phase of an MRI system, the magnetic field energy in the transmission phase is more than 1000 times of the magnetic field energy in the receiving phase. The induced voltage is between tens of volts and hundreds of volts during the transmit phase. The induced voltage in the receiving stage is less than 1V.

The third diode 213 and the fourth diode 214 are connected in anti-parallel. In the radio frequency transmitting stage, the radio frequency coil transmits radio frequency transmitting signals, and the field intensity of the magnetic field is larger. The induced voltage generated by the first magnetic field enhancement component 812 is relatively large. The voltages applied across the third diode 213 and the fourth diode 214 alternate in opposite directions. The applied voltage exceeds the turn-on voltage of the third diode 213 and the fourth diode 214, and the third diode 213 and the fourth diode 214 are turned on. The third capacitor 223 is connected in parallel with the first inductor 241, and a parallel resonance occurs, so that a circuit formed by the first inductor 241, the third diode 213, the fourth diode 214, and the third capacitor 223 is in a high-resistance state. During the rf signal emission phase, almost no current flows between the seventh structural capacitor 808 and the ninth structural capacitor 809. The magnetic field generated by the first magnetic field enhancement component 812 is weakened, so that the influence of the first magnetic field enhancement component 812 on the magnetic field in the transmission stage of the radio frequency signal is reduced, thereby reducing the artifact of the detected image and improving the definition of the detected image.

In the radio frequency receiving stage, the detection part transmits a feedback signal, and the field intensity of the magnetic field is smaller. The first magnetic field enhancement component 812 produces a smaller induced voltage. The applied voltage cannot reach the turn-on voltage of the third diode 213 and the fourth diode 214, and the third diode 213 and the fourth diode 214 are not turned on. The seventh capacitor 808 and the ninth capacitor 809 are connected through the third capacitor 223, and a current flows through them. The first cylindrical magnetic field enhancer 810 composed of the plurality of first magnetic field enhancing members 812 is in a resonance state, and plays a role of enhancing a magnetic field.

Referring to fig. 44 and 45, in one embodiment, the first magnetic field enhancement device 812 includes a second dielectric layer 831, a seventh electrode layer 832, an eighth electrode layer 833, a ninth electrode layer 834, a tenth electrode layer 835, a first electrode connection layer 123, and an eleventh electrode layer 836. The second dielectric layer 831 has a third surface 805 and a fourth surface 806 disposed opposite to each other. The second dielectric layer 831 has a third end 881 and a fourth end 882 disposed opposite thereto. A second via 220 is disposed in the middle of the second dielectric layer 831. The seventh electrode layer 832 is disposed on the third surface 805. The seventh electrode layer 832 covers a portion of the third surface 805. The seventh electrode layer 832 is disposed proximate the fourth end 882.

The eighth electrode layer 833 is disposed on the fourth surface 806. The eighth electrode layer 833 covers a portion of the fourth surface 806. The eighth electrode layer 833 is disposed near the middle of the second dielectric layer 831. The orthographic projection of the seventh electrode layer 832 on the second dielectric layer 831 overlaps the orthographic projection of the eighth electrode layer 833 on the second dielectric layer 831 to form a ninth structural capacitor 809. The ninth feature capacitor 809 is disposed near the middle of the second dielectric layer 831.

The ninth electrode layer 834 is disposed on the fourth surface 806. The ninth electrode layer 834 covers a portion of the fourth surface 806. The ninth electrode layer 834 is disposed proximate the fourth end 882. The ninth electrode layer 834 is spaced apart from the eighth electrode layer 833. The front projection of the ninth electrode layer 834 onto the second dielectric layer 831 is located in the front projection of the seventh electrode layer 832 onto the second dielectric layer 831, forming a seventh structural capacitance 808. The tenth electrode layer 835 is disposed on the third surface 805. The tenth electrode layer 835 covers a portion of the third surface 805. The tenth electrode layer 835 is disposed adjacent to the third end 881. The tenth electrode layer 835 is spaced apart from the seventh electrode layer 832.

The first electrode connection layer 123 is disposed on the second via 220. The first electrode connection layer 123 extends to the third surface 805 and the fourth surface 806, respectively. Both ends of the first electrode connection layer 123 are connected to the eighth electrode layer 833 and the tenth electrode layer 835, respectively. The eleventh electrode layer 836 is disposed on the fourth surface 806 with a gap from the eighth electrode layer 833. The eleventh electrode layer 836 covers a portion of the fourth surface 806. The eleventh electrode layer 836 is disposed proximate the third end 881. The front projection of the eleventh electrode layer 836 onto the second dielectric layer 831 is located in the front projection of the tenth electrode layer 835 onto the second dielectric layer 831, forming a sixth structure capacitance 807.

An orthographic projection of the eleventh electrode layer 836 onto the second dielectric layer 831 characterizes the structural size and shape of the eleventh electrode layer 836. The front projection of the eleventh electrode layer 836 onto the second dielectric layer 831 and a portion of the front projection of the tenth electrode layer 835 onto the second dielectric layer 831 are superimposed. At the overlapping portion, the eleventh electrode layer 836, the second dielectric layer 831, and the tenth electrode layer 835 form the sixth structural capacitor 807.

The tenth electrode layer 835 and the first electrode connecting layer 123 between the sixth structural capacitance 807 and the ninth structural capacitance 809 form a transmission line. The sixth structural capacitance 807 and the ninth structural capacitance 809 are connected in series via a transmission line. The seventh electrode layer 832 between the ninth structure capacitance 809 and the seventh structure capacitance 808 forms a transmission line. The ninth structural capacitor 809 and the seventh structural capacitor 808 are connected in series through a transmission line.

Thus, by the first magnetic field enhancement component 812 in the present embodiment, a structure in which three capacitances of the sixth structural capacitance 807, the ninth structural capacitance 809, and the seventh structural capacitance 808 are connected in series is formed.

The eighth electrode layer 833 and the tenth electrode layer 835 of different surfaces are connected through the second via hole 220 and the first electrode connection layer 123 such that the sixth structural capacitor 807 and the ninth structural capacitor 809 are connected in series. When combining a plurality of the first magnetic field enhancement elements 812 to form a magnetic field enhancement device, the eleventh electrode layer 836 and the ninth electrode layer 834 may be connected on the same side.

A gap is formed between the tenth electrode layer 835 and the seventh electrode layer 832, and the third surface 805 is exposed. Both ends of the first electrode connection layer 123 extend to the third surface 805 and the fourth surface 806, respectively, and connect the eighth electrode layer 833 and the tenth electrode layer 835 of different surfaces. The transmission line formed by the tenth electrode layer 835 and the first electrode connection layer 123 between the ninth structural capacitor 809 and the sixth structural capacitor 807 supplements the space corresponding to the gap, so that the space corresponding to the gap also has a magnetic field, and a situation that a certain part does not have a magnetic field does not occur. The two ends of the first electrode connection layer 123 extend to the third surface 805 and the fourth surface 806 respectively, and connect the eighth electrode layer 833 and the tenth electrode layer 835 on different surfaces, so that the magnetic field distribution is more uniform, and the imaging quality of the MRI apparatus is improved.

In one embodiment, the second via 220 is disposed near a middle of the second dielectric layer 831. And the diameter of the second via 220 is smaller than the width of the second dielectric layer 831.

In this embodiment, the first electrode connection layer 123 passes through the second via 220 to connect the tenth electrode layer 835 and the eighth electrode layer 833, respectively. The eighth electrode layer 833 is disposed opposite to the seventh electrode layer 832 to form the ninth capacitor 809. The second via 220 is disposed near the middle of the second dielectric layer 831, so that the ninth structural capacitor 809 is also disposed near the middle of the second dielectric layer 831, thereby improving the uniformity and symmetry of the magnetic field.

The diameter of the second via hole 220 is smaller than the width of the second dielectric layer 831, so that the area of the first electrode connection layer 123 in the second via hole 220 is reduced, and the stray capacitance formed by the first electrode connection layer 123 is further reduced.

In one embodiment, the tenth electrode layer 835, the first electrode connecting layer 123, and the eighth electrode layer 833 are integrally formed.

Referring to fig. 46, in one embodiment, the first magnetic field enhancement component 812 further includes a first external capacitor 440, a first diode 431, and a second diode 432. Both ends of the first external capacitor 440 are electrically connected to the seventh electrode layer 832 and the ninth electrode layer 834, respectively. The anode of the first diode 431 is electrically connected to the seventh electrode layer 832. The cathode of the first diode 431 is electrically connected to the ninth electrode layer 834. The cathode of the second diode 432 is electrically connected to the seventh electrode layer 832. The anode of the second diode 432 is electrically connected to the ninth electrode layer 834.

It is understood that the turn-on voltage of the first diode 431 and the second diode 432 may be between 0 volt and 1 volt. In one embodiment, the turn-on voltage of the first diode 431 and the second diode 432 may be 0.8V. The first diode 431 and the second diode 432 are connected in parallel between the seventh electrode layer 832 and the ninth electrode layer 834, and the first diode 431 and the second diode 432 are connected in reverse.

Due to the alternating nature of radio frequency. The induced voltage generated by the seventh electrode layer 832 and the eighth electrode layer 833 is also an ac voltage. In the radio frequency emission phase, the turn-on voltage of the first diode 431 and the second diode 432 has been exceeded due to the voltage difference between the seventh electrode layer 832 and the ninth electrode layer 834. Therefore, whichever of the seventh electrode layer 832 and the ninth electrode layer 834 has a higher voltage, one of the first diode 431 and the second diode 432 is always in an on state. The seventh electrode layer 832 and the ninth electrode layer 834 are thus electrically connected. The seventh structure capacitance 808 is shorted. The magnetic field enhancement device formed by the first magnetic field enhancement component 812 is in a detuned state.

And in the rf receiving stage, since the voltage difference between the seventh electrode layer 832 and the ninth electrode layer 834 is smaller than the turn-on voltage of the first diode 431 and the second diode 432. Therefore, whichever of the seventh electrode layer 832 and the ninth electrode layer 834 has a higher voltage, the first diode 431 and the second diode 432 are in a non-conductive state. The magnetic field enhancement device formed by the first magnetic field enhancement component 812 is in a resonant state.

In one embodiment, the element capacitance in the above embodiment may be a fixed capacitance or a tuning capacitance. When the frequency of the rf coil is determined, the element capacitance may be selected to be a suitable fixed capacitance, so that the fixed capacitance is matched with other structures of capacitance and element capacitance, so that the resonant frequency of the loop where the magnetic field enhancing device 10 is located is equal to the frequency of the rf coil, and the effect of enhancing the magnetic field is further achieved. When the frequency of the radio frequency coil is not determined, the element capacitance may be an adjustable capacitance. By adjusting the adjustable capacitance, the resonant frequency is adjusted so that the magnetic field enhancing device 10 is adaptable to different operating environments.

In one embodiment, the diameter of the second cylindrical magnetic field enhancer 820 is 100mm. The transmission line width of the first electrode layer 110 and the second electrode layer 120 in the second magnetic field enhancing member 822 is 4mm. The width of the first dielectric layer 100 is 15mm. The first capacitor 405 is disposed at an intermediate position, and has a capacitance value of 40pF. The length of the first dielectric layer 100 is 250mm. The material of the first dielectric layer 100 is Rogers 4003C, and the thickness is 0.51mm. The resonance frequency of the second cylindrical magnetic field enhancer 820 is 52MHz, corresponding to the operating frequency of the mri system when the main magnetic field strength is 3T. The second cylindrical magnetic field enhancer 820 is used to enhance the nuclear magnetic signal of the non-hydrogen daughter nuclei of ³¹ P.

The diameter of the first cylindrical magnetic field enhancer 810 is 120mm. The transmission line width of the seventh electrode layer 832 between the sixth structural capacitance 807 and the seventh structural capacitance 808 in the first magnetic field enhancing component 812 is 4mm. The width of the second dielectric layer 831 is 15mm. The sixth structural capacitance 807 and the seventh structural capacitance 808 are located across the first magnetic field enhancing component 812. The length of the electrode overlapping portion of the sixth structural capacitor 807 and the seventh structural capacitor 808 is 15mm. The material of the second dielectric layer 831 is Rogers 4003C, and the thickness is 0.51mm. The length of the second dielectric layer 831 is 250mm. The resonance frequency of the first cylindrical magnetic field enhancer 810 is 128MHz, corresponding to the operating frequency of the mri system when the main magnetic field strength is 3T. The first cylindrical magnetic field enhancer 810 is used for enhancing the nuclear magnetic signal of the hydrogen nuclei of ¹ H.

Referring to fig. 47 and 48, the first magnetic field enhancement device 812 includes a second dielectric layer 831, a seventh electrode layer 832, an eighth electrode layer 833, a first depletion MOS 231 and a second depletion MOS 232. The second dielectric layer 831 has a third surface 805. The second dielectric layer 831 has a third end 881 and a fourth end 882 disposed opposite thereto. The seventh electrode layer 832 is disposed on the third surface 805. The seventh electrode layer 832 is disposed proximate the fourth end 882. The eighth electrode layer 833 is disposed on the third surface 805. The eighth electrode layer 833 is spaced apart from the seventh electrode layer 832. The eighth electrode layer 833 is disposed adjacent to the third end 881. The source of the first depletion MOS 231 is connected to the eighth electrode layer 833. The gate and the drain of the first depletion MOS tube 231 are connected. The gate and drain of the second depletion MOS transistor 232 are connected. The gate and drain of the second depletion MOS transistor 232 are connected to the gate and drain of the first depletion MOS transistor 231. The source of the second depletion MOS transistor 232 is connected to the seventh electrode layer 832.

The first depletion MOS tube 231 and the second depletion MOS tube 232 are connected in reverse series, so that the seventh electrode layer 832 and the eighth electrode layer 833 can be controlled to be disconnected in a radio frequency transmitting stage and connected in a radio frequency receiving stage. In the radio frequency emission stage, the first depletion type MOS tube 231 and the second depletion type MOS tube 232 are connected in reverse series, so that the device can be adapted to an alternating current environment in MRI equipment. In any case, it is ensured that one of the first depletion type MOS transistor 231 and the second depletion type MOS transistor 232 is turned off, so that the eighth electrode layer 833 and the seventh electrode layer 832 are disconnected and not connected.

In the rf receiving stage, the first depletion MOS 231 and the second depletion MOS 232 are turned on, so as to ensure that the seventh electrode layer 832 is connected to the eighth electrode layer 833. The first cylindrical magnetic field enhancers 810 formed by the plurality of first magnetic field enhancing components 812 are in a connection state, and can be in a resonance state, so that a signal field is greatly enhanced, and an image signal-to-noise ratio is enhanced.

Therefore, the seventh electrode layer 832 and the eighth electrode layer 833 are controlled to be disconnected in the radio frequency transmitting stage and connected in the radio frequency receiving stage by the first depletion MOS transistor 231 and the second depletion MOS transistor 232, so that the first magnetic field enhancement component 812 can only enhance the radio frequency receiving field, and can not enhance the radio frequency transmitting field, thereby improving the signal to noise ratio of the image.

In one embodiment, the second dielectric layer 831 further includes a fourth surface 806. The fourth surface 806 is disposed opposite the third surface 805. The first magnetic field enhancement component 812 also includes a ninth electrode layer 834 and the tenth electrode layer 835. The ninth electrode layer 834 is disposed on the fourth surface 806. The ninth electrode layer 834 covers a portion of the fourth surface 806. The ninth electrode layer 834 is disposed proximate the fourth end 882. The tenth electrode layer 835 is disposed on the fourth surface 806. The tenth electrode layer 835 covers a portion of the fourth surface 806. The tenth electrode layer 835 is disposed adjacent to the third end 881.

The orthographic projection of the ninth electrode layer 834 on the second dielectric layer 831 and the orthographic projection of the seventh electrode layer 832 on the second dielectric layer 831 are partially overlapped to form a seventh structural capacitor 808. In the heavy and portions, the seventh electrode layer 832, the second dielectric layer 831, and the ninth electrode layer 834 form the seventh structural capacitance 808. The orthographic projection of the tenth electrode layer 835 on the second dielectric layer 831 and the orthographic projection of the eighth electrode layer 833 on the second dielectric layer 831 are overlapped to form a sixth structural capacitor 807. In the heavy and partial, the eighth electrode layer 833, the second dielectric layer 831, and the tenth electrode layer 835 form the sixth structural capacitance 807.

The eighth electrode layer 833 between the sixth structure capacitance 807 and the first depletion MOS transistor 231 may form a first transmission line. The seventh electrode layer 832 between the second depletion MOS transistor 232 and the seventh structural capacitor 808 may form a second transmission line. The sixth structure capacitor 807, the first depletion MOS transistor 231, the second depletion MOS transistor 232, and the seventh structure capacitor 808 are connected in series through a first transmission line and a second transmission line. Therefore, by connecting the sixth structure capacitor 807, the first depletion MOS transistor 231, the second depletion MOS transistor 232, and the seventh structure capacitor 808 in series, the resonant frequency of the first cylindrical magnetic field enhancer 810 formed by the plurality of first magnetic field enhancing members 812 can be adjusted, and the adjustment time of the first cylindrical magnetic field enhancer 810 after being put into the nuclear magnetic resonance imaging system can be shortened.

The first magnetic field enhancement component 812 generates an induced voltage in a magnetic field environment. The transmission line portion formed by the seventh electrode layer 832 and the eighth electrode layer 833 may form parasitic capacitance. The parasitic capacitance is in parallel relationship with the seventh structure capacitance 808 and the sixth structure capacitance 807. In the rf receiving stage, the sixth structure capacitor 807 and the seventh structure capacitor 808 form a capacitor series structure, dividing the induced voltage into a plurality of parts, and reducing the voltage division between the sixth structure capacitor 807 and the seventh structure capacitor 808.

Further, the sixth structure capacitor 807 and the seventh structure capacitor 808 form a capacitor series structure, which can reduce the voltage on the parasitic capacitor. The voltage on the parasitic capacitance is reduced, and the harm of the parasitic capacitance is reduced, so that the load effect is reduced. The load effect of the first magnetic field enhancement component 812 is reduced, so that the resonance frequency of the first cylindrical magnetic field enhancer 810 formed by the plurality of first magnetic field enhancement components 812 is not easily affected by the object to be tested, enhancing the enhancement performance of the first cylindrical magnetic field enhancer 810, and enhancing the stability of the resonance frequency.

In one embodiment, the overlap length is related to the overlap area at the corresponding heavy sum portion of the sixth structure capacitance 807. The sixth structural capacitor 807 and the seventh structural capacitor 808 each have a suitable facing area, meaning that the structural capacitor formed by the eighth electrode layer 833 and the tenth electrode layer 835 has a suitable value such that the first cylindrical magnetic field enhancer 810 formed by the plurality of first magnetic field enhancing members 812 has the same operating frequency as the MRI system.

Wherein the resonant frequency of the first cylindrical magnetic field enhancer 810 formed by the plurality of first magnetic field enhancing members 812 is determined by the following formulaWhere L and C are the equivalent inductance and the equivalent capacitance, respectively, in the resonant tank of the first cylindrical magnetic field enhancer 810 formed by the plurality of first magnetic field enhancing members 812. The value of the equivalent capacitance is determined by the structural capacitance Cs of each cell. The relation between the structural capacitance Cs and the facing area S of the two electrode plates is/>Wherein ε ₀ is the vacuum dielectric constant and ε is the relative dielectric constant of the second dielectric layer 831. d is the distance between the two electrode plates (or the thickness of the second dielectric layer 831). Therefore, a suitable facing area is to provide the first cylindrical magnetic field enhancer 810 formed by the plurality of first magnetic field enhancing members 812 with a target resonant frequency, i.e., the same operating frequency as the MRI system.

Referring to fig. 49, in one embodiment, in the heavy portion and the part corresponding to the sixth structural capacitor 807, the overlapping length of the eighth electrode layer 833 and the tenth electrode layer 835 is 35mm. In the heavy portion corresponding to the seventh structural capacitor 808, the overlapping length of the seventh electrode layer 832 and the ninth electrode layer 834 is 35mm.

In one embodiment, the length of the eighth electrode layer 833 between the sixth structural capacitance 807 and the first depletion MOS transistor 231 is the same as the length of the seventh electrode layer 832 between the seventh structural capacitance 808 and the second depletion MOS transistor 232. That is, the lengths of the first transmission line and the second transmission line are the same in the direction from the third end 881 to the fourth end 882.

The first transmission line and the second transmission line may be equivalent to an inductance and a resistance. An effective magnetic field is distributed between the first transmission line and the second transmission line. The effective magnetic field between the seventh structure capacitance 808 and the second depletion MOS transistor 232 forms a first detection region. The effective magnetic field between the sixth structure capacitance 807 and the first depletion MOS transistor 231 forms a second detection region. The first detection area is identical to the second detection area. The region where the effective magnetic field is formed is used as a detection region, and the detection part is detected. In this embodiment, the first magnetic field enhancement component 812 forms two identical detection regions on the left and right sides of the first depletion MOS tube 231 and the second depletion MOS tube 232, which is more beneficial for the first magnetic field enhancement component 812 to form a uniform magnetic field, and improves the quality of MRI images.

Referring to fig. 47, the dual-core magnetic field enhancement device 30 of the present application has two resonance peaks with resonance frequencies of 51.6MHz and 128.8MHz, respectively. Therefore, the dual-core magnetic field enhancement device 30 can enhance the signal fields ³¹ P and ¹ H simultaneously, can detect different target cores at the same position, and can display MRI imaging information corresponding to the different target cores at the detection position.

In one embodiment, the present application provides a magnetic resonance system comprising the dual nuclear magnetic field enhancement device 30 of any of the above embodiments.

In the description of the present specification, reference to the terms "some embodiments," "other embodiments," "desired embodiments," and the like, means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description. The above examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the claims. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims.

Claims

1. A dual nuclear magnetic field enhancement device, comprising: a first cylindrical magnetic field enhancer (810) and a second cylindrical magnetic field enhancer (820);

The first cylindrical magnetic field enhancer (810) comprises:

A first cylindrical holder (811) having a first outer surface (801) and a first inner surface (802), the first outer surface (801) surrounding the first inner surface (802) and being disposed in spaced opposition to the first inner surface (802), the first inner surface (802) surrounding a first accommodation space (819);

A plurality of first magnetic field enhancement members (812), wherein the extending direction of the first magnetic field enhancement members (812) is the same as the extending direction of the first central axis of the first cylindrical bracket (811), and the first magnetic field enhancement members are arranged on the first outer surface (801) at intervals around the first central axis of the first cylindrical bracket (811); each first magnetic field enhancement assembly (812) has a first end and a second end disposed opposite each other, the first ends of the plurality of first magnetic field enhancement assemblies (812) being connected in sequence, the second ends of the plurality of first magnetic field enhancement assemblies (812) being connected in sequence;

the second cylindrical magnetic field enhancer (820) comprises:

A second cylindrical holder (821) disposed in the first accommodation space (819), the second cylindrical holder (821) having a second outer surface (803) disposed in spaced opposition to the first inner surface (802);

A plurality of second magnetic field enhancement members (822) disposed on the second outer surface (803) at intervals, wherein the extending direction of the second magnetic field enhancement members (822) is the same as the extending direction of the second central axis of the second cylindrical bracket (821); each second magnetic field enhancement assembly (822) has a first end and a second end which are oppositely arranged, the first ends of the plurality of second magnetic field enhancement assemblies (822) are sequentially connected, and the second ends of the plurality of second magnetic field enhancement assemblies (822) are sequentially connected; wherein,

The second magnetic field enhancement component (822) comprises a first dielectric layer (100), a first electrode layer (110), a second electrode layer (120), a third capacitor (223), a first inductor (241) and a first switch circuit (631), wherein one end of the third capacitor (223) is connected with the first electrode layer (110), the other end of the third capacitor (223) is connected with the second electrode layer (120), and one end of the first inductor (241) is connected with the second electrode layer (120); the first switch circuit (631) comprises a fifth enhancement MOS tube (235) and a sixth enhancement MOS tube (236), wherein the drain electrode and the grid electrode of the fifth enhancement MOS tube (235) are respectively connected with one end of the first inductor (241) far away from the second electrode layer (120), the source electrode of the fifth enhancement MOS tube (235) is connected with the first electrode layer (110), the drain electrode and the grid electrode of the sixth enhancement MOS tube (236) are respectively connected with the first electrode layer (110), the source electrode of the sixth enhancement MOS tube (236) is connected with one end of the first inductor (241) far away from the second electrode layer (120), the fifth enhancement MOS tube (235) and the sixth enhancement MOS tube (236) are connected in reverse parallel, and when the loaded voltage exceeds the channel conduction voltage of the fifth enhancement MOS tube (235) and the sixth enhancement MOS tube (236), the drain electrode of the fifth enhancement MOS tube (235) is conducted and the drain electrode of the sixth enhancement MOS tube (236) is conducted alternately.

2. The dual-core magnetic field enhancement device according to claim 1, wherein during the radio frequency receiving phase, the source-drain electrode of the fifth enhancement MOS transistor (235) is conductive and the source-drain electrode of the sixth enhancement MOS transistor (236) is non-conductive, and the second cylindrical magnetic field enhancer (820) composed of the plurality of second magnetic field enhancing components (822) is in a resonant state.

3. The binuclear magnetic field enhancement device of claim 1, further comprising:

A plurality of first resonance control circuits (851), one of the first resonance control circuits (851) being electrically connected to one of the first magnetic field enhancement components (812) for controlling the operational state of the first magnetic field enhancement component (812).

4. The binuclear magnetic field enhancement device of claim 1, further comprising:

A plurality of second resonant control circuits (852), one of said second resonant control circuits (852) being electrically connected to one of said second magnetic field enhancement assemblies (822) for controlling the operational state of said second magnetic field enhancement assembly (822).

5. The dual nuclear magnetic field enhanced device of claim 1 wherein the first magnetic field enhanced component (812) comprises:

A second dielectric layer (831) having third (805) and fourth (806) surfaces spaced apart opposite, the second dielectric layer (831) having third (881) and fourth (882) opposite ends;

a seventh electrode layer (832) provided on the third surface (805) and covering the third surface (805);

an eighth electrode layer (833) disposed on the fourth surface (806) and covering a portion of the fourth surface (806), the eighth electrode layer (833) being disposed proximate to the third end (881);

a ninth electrode layer (834) disposed on the fourth surface (806) at a distance from the eighth electrode layer (833) and covering a portion of the fourth surface (806), the ninth electrode layer (834) being disposed proximate to the fourth end (882);

-a sixth structural capacitance (807) is formed by the orthographic projection of the eighth electrode layer (833) on the second dielectric layer (831) and by the orthographic projection of the seventh electrode layer (832) on the second dielectric layer (831);

The ninth electrode layer (834) is in front projection of the second dielectric layer (831), and the seventh electrode layer (832) is in front projection of the second dielectric layer (831) to form a seventh structural capacitance (808).

6. The dual nuclear magnetic field enhanced device of claim 5 wherein a width of the seventh electrode layer (832) between the sixth structural capacitance (807) and the seventh structural capacitance (808) is smaller than a width of the seventh electrode layer (832) corresponding to the sixth structural capacitance (807) and the seventh structural capacitance (808) in a direction surrounding the first central axis of the first cylindrical support (811).

7. The dual nuclear magnetic field enhanced device of claim 1 wherein a first central axis of the first cylindrical magnetic field enhancer (810) coincides with a second central axis of the second cylindrical magnetic field enhancer (820) and a mid-section of the first cylindrical magnetic field enhancer (810) coincides with a mid-section of the second cylindrical magnetic field enhancer (820);

Along the first central axis direction, the length of the first cylindrical magnetic field enhancer (810) is smaller than the length of the second cylindrical magnetic field enhancer (820), and two ends of the first cylindrical magnetic field enhancer (810) are not coplanar with two ends of the second cylindrical magnetic field enhancer (820).

8. A magnetic resonance system comprising a binuclear magnetic field enhancing device as defined in any one of claims 1 to 7.