Device for improving magnetic field intensity of partial region of radio frequency coil

Abstract

The invention relates to the technical field of radio frequency coils, and particularly discloses a device for improving the magnetic field intensity of a partial region of a radio frequency coil, and the device comprises an outer coil which serves as a main magnetic field generation element and is used for generating a basic magnetic field in the internal space of the device; the plurality of metal small rings are uniformly and coaxially distributed in the internal space of the outer side coil in an annular array mode, and each metal small ring has one or two of the following freedom degree adjusting modes at the same time so as to adapt to scanning samples of different sizes: radial stretching: each metal small ring can be independently subjected to stretching adjustment along the radial direction of the metal small ring; and axial rotation: each metal small ring can independently rotate around the tail end of the metal small ring. The method has high adaptability to scanning samples of different sizes and shapes, can achieve the remarkable enhancement of a magnetic field in a specific area, and effectively improves the radio frequency excitation efficiency and the receiving signal-to-noise ratio.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of radio frequency coils, and particularly relates to a device for improving the magnetic field strength of a partial area of a radio frequency coil. BACKGROUND

[0002] In magnetic resonance imaging (MRI) technology, the transmitting coil is one of the core components. Traditionally, volumetric designs such as toroidal or solenoid coils are used, such as solenoid coils and Helmholtz coils. They can efficiently excite atomic nuclei in the enclosed space to obtain magnetic resonance signals. These coils capture these signals through dedicated receiving coils or the same coil with transceiver conversion function, thereby realizing non-invasive detection of biological tissues or samples. However, a significant challenge is that when facing samples of different sizes, it is difficult to achieve optimal radio frequency excitation efficiency and receiving signal-to-noise ratio due to the fixed size of the volumetric coil and the difficulty in adjusting it. Smaller coil size can improve local radio frequency efficiency and signal-to-noise ratio, but its scope of application is limited.

[0003] To overcome this limitation, researchers have explored the use of metamaterials to enhance the magnetic field strength of specific areas of the coil. Metamaterials, with their unique periodic structure, can exhibit abnormal electromagnetic properties such as negative effective permittivity or negative effective permeability, thereby achieving magnetic field enhancement at specific locations. However, this method faces challenges in low-frequency applications because the size of the metamaterial structure required to achieve resonance at low frequencies is large, and its resonant characteristics are easily disturbed by the coil frequency. When placed close together, it may even reduce the efficiency of the coil.

[0004] Currently, there have been studies such as the Lenz lens concept proposed by J. Schoenmaker et al., as described in the reference paper (J. Schoenmaker, K. R. Pirota, and J. C. Teixeira: Magnetic flux amplification by Lenz lenses. Review of Scientific Instruments, 84(8), 2013. http: / / dx.doi.org / 10.1063 / 1.4819234.), which shows the potential of magnetic field amplification in the low-frequency KHz range, but its application is limited to low frequencies and the design is relatively simple, only using a single-layer double-loop structure. The application and the influence of multi-layer and multi-loop structures on magnetic field enhancement have not been further explored. In addition, although the patent with the patent publication number US11002810B2 mentions the use of multiple lenses in multiple layers in parallel, the optimization of the number of loops in a single layer and the controllability of the magnetic field enhancement space still need to be further explored.

[0005] Therefore, we propose a device for improving the magnetic field strength of the partial area of the radio frequency coil to solve the above technical problems. SUMMARY

[0006] In order to solve the technical problems existing in the prior art, the present application proposes a device for improving the magnetic field strength of the partial area of the radio frequency coil.

[0007] The technical solutions adopted by the present application are as follows:

[0008] A device for improving the magnetic field strength of the partial area of the radio frequency coil, comprising:

[0009] An outer coil, as a main magnetic field generating element, for generating a basic magnetic field in the internal space of the device;

[0010] A plurality of metal small rings are uniformly and coaxially distributed in the internal space of the outer coil in a ring array, each of the metal small rings simultaneously has one or both of the following freedom adjustment modes to adapt to different sizes of scanning samples:

[0011] Radial expansion: each metal small ring can be independently adjusted in the radial direction;

[0012] Axial rotation: each metal small ring can be independently rotated around its tail end.

[0013] In a further technical solution, the internal space of the outer coil is provided with an insulating support, and the tail of the metal small ring is connected to the insulating support.

[0014] In a further technical solution, the tail end of the metal small ring is provided with a rotating shaft, and the rotating shaft is rotatably connected to the insulating support.

[0015] In a further technical solution, the shape of the metal small ring is trapezoidal or rectangular.

[0016] In a further technical solution, the metal small ring comprises a tail end rod, a head end rod, and two oppositely arranged side rods, the two side rods are connected between the two ends of the tail end rod and the head end rod respectively, forming a closed ring structure, and the head end rod and the side rod can be adjusted in the length direction.

[0017] In a further technical solution, the head end rod comprises a plurality of first sleeves that are sequentially sleeved, and can be adjusted in the length direction of the head end rod.

[0018] In a further technical solution, the side rod comprises a plurality of second sleeves that are sequentially sleeved, and can be adjusted in the length direction of the side rod.

[0019] In a further technical solution, the outer coil is provided with a plurality of metal small rings.

[0020] In summary, due to the adoption of the above technical solutions, the present application has the following advantages:

[0021] The metal small rings in the present application are adjusted by the radial expansion and contraction freedom and the axial rotation freedom, and the combination is flexible. In practical application, in the face of diversified scanning samples that may appear in the central scanning area of the outer coil, whether the sample is large in size or irregular in shape, the device shows high adaptability, thereby realizing significant enhancement of the magnetic field in a specific area, and effectively improving the radio frequency excitation efficiency and the signal-to-noise ratio of reception. BRIEF DESCRIPTION OF DRAWINGS

[0022] The present application will be described by way of example and with reference to the accompanying drawings, in which:

[0023] Figure 1 is a structural schematic diagram of the present application;

[0024] Figure 2 is Figure 1 is a partial enlarged schematic view of A in the present application;

[0025] Figure 3 is a structural schematic diagram of the metal small ring of the present application.

[0026] Reference signs: 1-outer coil, 2-metal small ring, 3-insulating support, 4-rotation shaft, 5-tail end rod, 6-head end rod, 61-first sleeve, 7-side rod, 71-second sleeve. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0028] Embodiment 1:

[0029] Referring to Figure 1 , the present embodiment provides a device for improving the magnetic field strength of a part of a radio frequency coil, comprising:

[0030] The outer coil 1 is used as a main magnetic field generating element to generate a basic magnetic field in the internal space of the device.

[0031] Eight metal mini-rings 2 are evenly and coaxially distributed in the inner space of the outer coil 1 in a ring array, each of which can be independently adjusted in its radial direction to adapt to different sizes of scanning samples.

[0032] Through the above-mentioned design, the outer coil 1 as the main magnetic field generating element can flexibly select a volume type transmitting coil or a transmitting-receiving integrated coil, and the shape is preferably circular or elliptical to maximize the uniformity and efficiency of the magnetic field distribution. By generating a basic magnetic field in the inner space of the device, this basic magnetic field is the basis for the subsequent magnetic field enhancement process. In actual application, in the face of diversified scanning samples that may appear in the central scanning area of the outer coil 1, whether it is a larger sample or an irregularly shaped sample, the device shows high adaptability. Thanks to the radial expansion and contraction characteristics of each metal mini-ring 2, the device can dynamically adjust its internal magnetic field distribution to match different scanning requirements in size and shape. This flexibility not only ensures smooth passage of the sample, but also effectively changes the magnetic field distribution inside and outside the metal mini-ring 2, optimizes the interaction with the magnetic field of the outer coil 1, and thus enhances the corresponding magnetic field according to the size of the different samples. During the scanning process, the magnetic field generated by the metal mini-ring 2 in its interior is opposite to the magnetic field direction of the outer coil 1 in this area, realizing the mutual offset of the local magnetic field. At the same time, the magnetic field generated by the metal mini-ring 2 in its exterior is the same as the magnetic field direction of the outer coil 1, realizing the superposition effect of the magnetic field. This superposition effect enhances the magnetic field strength in the central scanning area of the outer coil 1, which means that the excitation efficiency of the radio frequency signal in the sample is higher, thereby reducing the required radio frequency power and scanning time, which has a positive effect on improving the imaging speed and reducing the energy consumption of the device. In addition, the enhanced magnetic field strength directly improves the received signal-to-noise ratio, which is crucial for high-resolution imaging, which can reduce the data acquisition time while maintaining image clarity.

[0033] In this embodiment, referring to Figure 1 and Figure 2 , the inner part of the outer coil 1 is provided with an insulating support 3, and the tail of the metal mini-ring 2 is connected to the insulating support 3.

[0034] The material of the insulating support 3 usually has good insulation performance, which can reduce the electromagnetic interference between the metal mini-ring 2 and the outer coil 1. By providing stable support for the metal mini-ring 2 through the insulating support 3, the stability and reliability of the metal mini-ring 2 during the adjustment process are ensured, which helps to prevent the metal mini-ring 2 from shaking or deviating during the adjustment, and ensures the stability and consistency of the magnetic field enhancement.

[0035] In this embodiment, referring to Figure 1 and Figure 3, the metal ring 2 is in the shape of a ladder, including a tail end rod 5, a head end rod 6, and two oppositely arranged side rods 7, which are connected between the two ends of the tail end rod 5 and the head end rod 6 respectively, forming a closed ring structure, the head end rod 6 includes two first sleeves 61 connected in sequence, which can be adjusted in length direction of the head end rod 6, the side rod 7 includes four second sleeves 71 connected in sequence, which can be adjusted in length direction of the side rod 7.

[0036] The head end rod 6 and the side rod 7 of the metal ring 2 are designed with telescopic sleeve structure, allowing length adjustment in the length direction, so that the metal ring 2 can flexibly adapt to scanning samples of different sizes and shapes, ensuring that the magnetic field enhancement effect is optimal, which is conducive to use. It is worth mentioning that the shape of the metal ring 2 can also be rectangular and polygonal in addition to the ladder shape. This diversified shape selection not only enriches the design space of the metal ring 2, but also provides more possibilities for magnetic field optimization in different application scenarios.

[0037] Embodiment 2:

[0038] Different from embodiment 1, referring to Figure 1 , the embodiment provides a device for improving the magnetic field strength of the radio frequency coil in part, comprising:

[0039] The outer coil 1 is used as the main magnetic field generating element to generate a basic magnetic field in the internal space of the device.

[0040] Eight metal rings 2 are evenly and coaxially distributed in the internal space of the outer coil 1 in a ring array, and each metal ring 2 can be independently rotated around its tail end to adapt to scanning samples of different sizes.

[0041] Compared with embodiment 1, this embodiment focuses on providing an axial rotation freedom adjustment method, which is in sharp contrast to the radial telescopic freedom adjustment method in embodiment 1. In actual application, when facing scanning samples with special shapes, one end is large and the middle is small in the central scanning area of the outer coil 1, the design of this embodiment is particularly critical. Specifically, by giving the metal ring 2 the freedom of axial rotation, we can flexibly adjust the orientation and angle of the metal ring 2 according to the specific shape of the scanning sample. When encountering a large end, the operator can rotate the metal ring 2 to pass the scanning sample, thereby effectively avoiding the occurrence of collision or jamming phenomenon. In addition, the introduction of axial rotation freedom further enhances the adaptability and flexibility of the metal ring 2, so that the metal ring 2 can more closely fit the contour of the scanning sample, enhancing the magnetic field strength in the sample area, thereby ensuring the scanning quality while reducing unnecessary energy loss.

[0042] In the embodiment, referring to Figure 1 and Figure 2 The inner side of the outer coil 1 is provided with an insulating support 3, and the tail end of the metal ring 2 is provided with a rotating shaft 4 which is rotatably connected to the insulating support 3.

[0043] The metal ring 2 is connected to the insulating support 3 through the rotating shaft 4 at the tail end, realizing free rotation in the axial direction, so that the metal ring 2 can flexibly cope with scanning samples of different shapes and sizes, ensuring smooth passage of the sample while maintaining the effect of magnetic field enhancement.

[0044] It is worth mentioning that the rotating shaft 4 can hover at the current angle after rotation, and the skilled person in the art can completely realize it by using conventional technical means in the prior art, so this place will not be repeated here.

[0045] Embodiment 3:

[0046] Different from embodiment 1 or embodiment 2, referring to Figure 1 The embodiment provides a device for improving the magnetic field strength of a part of a radio frequency coil, characterized in that it comprises:

[0047] An outer coil 1, as a main magnetic field generating element, is used to generate a basic magnetic field in the internal space of the device;

[0048] Eight metal rings 2 are evenly and coaxially distributed in the internal space of the outer coil 1 in a ring array, and each of the metal rings 2 has the following two degrees of freedom adjustment modes to adapt to scanning samples of different sizes:

[0049] Radial expansion: each metal ring 2 can be independently adjusted in the radial direction;

[0050] Axial rotation: each metal ring 2 can be independently rotated around the tail end.

[0051] Compared with embodiment 1 or embodiment 2, the embodiment focuses on providing a combination of radial expansion degree of freedom adjustment and axial rotation degree of freedom adjustment, and through the double degree of freedom adjustment of the metal ring 2, the adaptability of the device is greatly improved, which can better cope with more complex scanning samples of different sizes or different shapes, so as to realize the significant enhancement of the magnetic field in a specific area.

[0052] Embodiment 4:

[0053] The embodiment is obtained by further optimizing embodiment 1, embodiment 2 or embodiment 3, and in the embodiment, a plurality of metal rings 2 are arranged in the outer coil 1.

[0054] The number of layers of the metal small rings 2 inside the outer coil 1 is increased, which can significantly increase the magnetic field intensity of the radio frequency coil in a partial area. Each layer of the metal small rings 2 interacts with the magnetic field generated by the outer coil 1, and additional magnetic fields are generated inside and around the metal small rings 2 through electromagnetic induction principle, thereby superimposing and enhancing the original magnetic field, and effectively improving the imaging quality and signal-to-noise ratio.

[0055] The above description is only an embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation, or direct or indirect application in other related technical fields, which is made by using the content of the specification and drawings of the present application, is also included in the patent protection scope of the present application.

Claims

1. An apparatus for increasing the magnetic field strength in a portion of a radio frequency coil, comprising: The utility model relates to a kind of magnetic field scanning device, including: Outer coil (1) is used as main magnetic field generating element, for generating basic magnetic field in device internal space; Multiple metal small rings (2) are evenly and coaxially distributed in the internal space of outer coil (1) in annular array, each metal small ring (2) simultaneously possesses one or two of following freedom degree adjustment mode, to adapt to different size scanning sample: Radial telescoping: each metal small ring (2) can be independently adjusted along its radial direction; Axial rotation: each metal small ring (2) can be independently rotated around its tail end.

2. The apparatus of claim 1, wherein, The inside of the outer coil (1) is provided with an insulating support (3), and the tail of the metal small ring (2) is connected to the insulating support (3).

3. The apparatus of claim 2, wherein the plurality of conductive elements are arranged in a pattern that increases the magnetic field strength in a portion of the volume of space. The tail end of the metal small ring (2) is provided with a rotating shaft (4), and the rotating shaft (4) is rotatably connected to the insulating support (3).

4. The apparatus of claim 1, wherein, The shape of the metal small ring (2) is trapezoidal or rectangular.

5. The apparatus of claim 4, wherein the plurality of conductive elements are arranged in a pattern that is substantially symmetrical about a center of the RF coil. The metal small ring (2) includes a tail end rod (5), a head end rod (6), and two oppositely arranged side rods (7), the two side rods (7) are connected between the two ends of the tail end rod (5) and the head end rod (6) respectively, forming a closed ring structure, and the head end rod (6) and the side rod (7) can be telescoped along the length direction.

6. The apparatus of claim 5, wherein the plurality of conductive elements are arranged in a pattern that increases the magnetic field strength in a portion of the volume of space. The head end rod (6) includes a plurality of first sleeves (61) that are sequentially sleeved, and can be telescoped along the length direction of the head end rod (6).

7. The apparatus of claim 5, wherein the plurality of conductive elements are arranged in a pattern that is substantially symmetrical about a center of the RF coil. The side rod (7) includes a plurality of second sleeves (71) that are sequentially sleeved, and can be telescoped along the length direction of the side rod (7).

8. The apparatus for increasing the magnetic field strength in a portion of a radio frequency coil of any of claims 1-7, wherein, Multiple metal small rings (2) are arranged in the outer coil (1).

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