Circularly polarized intelligent metamaterial radio frequency enhancer and bilateral breast magnetic resonance imaging system

Abstract

Disclosed in the present invention are a circularly polarized intelligent metamaterial radio frequency enhancer (1) and a bilateral breast magnetic resonance imaging system (2). The circularly polarized intelligent metamaterial radio frequency enhancer (1) comprises a hollow cylindrical dielectric substrate (11), conductive rings (12), conductive connecting members (13), and tunable capacitors (14). A plurality of conductive rings (12) are sleeved on the outer circumference of the hollow cylindrical dielectric substrate (11) along the axial direction thereof. Each conductive ring (12) is provided with an opening (121) in the circumferential direction of the conductive ring (12). A tunable capacitor (14) is disposed in the opening (121) of each conductive ring (12). Every two adjacent conductive rings (12) are connected by means of a conductive connecting member (13). The bilateral breast magnetic resonance imaging system (2) comprises a pair of circularly polarized intelligent metamaterial radio frequency enhancers (1), wherein the pair of circularly polarized intelligent metamaterial radio frequency enhancers (1) respectively correspond to bilateral breast positions of a human body.

Description

Circularly polarized intelligent metamaterial radio frequency intensifier and dual-mast magnetic resonance imaging system Technical Field

[0001] This invention belongs to the field of medical diagnostic technology, and relates to magnetic resonance imaging technology, and in particular to a circularly polarized intelligent metamaterial radio frequency intensifier and a dual-mast magnetic resonance imaging system for magnetic resonance imaging. Background Technology

[0002] The importance of magnetic resonance imaging (MRI) in lesion imaging cannot be ignored. For example, in breast imaging, bilateral MRI is more important than single-breast MRI due to its more comprehensive assessment capabilities. Bilateral imaging can reveal the symmetry and differences between the two breasts, helping to detect occult lesions and multifocal tumors that may be missed in unilateral imaging. Furthermore, bilateral MRI is particularly important in screening high-risk patients because it provides a more comprehensive picture of breast health, thereby optimizing diagnostic and treatment decisions. This comprehensiveness not only increases the chance of early detection of breast cancer but also provides crucial information for developing personalized treatment plans, making patient management more precise.

[0003] One of the challenges of bilateral breast MRI is the signal-to-noise ratio (SNR). A low SNR can impair tumor visualization, increasing the risk of missed or misdiagnosed lesions. Furthermore, a low SNR can make subtle lesions difficult to identify, thus affecting physician judgment and treatment decisions. Therefore, improving the SNR of bilateral breast MRI is one of the key challenges in enhancing its clinical application.

[0004] Metamaterials offer a novel technological solution for improving the signal-to-noise ratio (SNR) of bilateral breast MRI. Metamaterials are a class of artificially designed and manufactured composite materials whose structures are typically designed at the subwavelength scale to control the material's interaction with electromagnetic or acoustic waves. The role of metamaterials in improving the SNR of breast MRI is primarily manifested in their ability to enhance and focus radiofrequency magnetic fields. By focusing the radiofrequency magnetic field generated by a large-diameter radiofrequency coil, the magnetic field is effectively concentrated in the breast region, thereby enhancing signal reception in that area, increasing the signal-to-noise ratio, and thus improving the SNR. Therefore, metamaterials play a crucial role in the development of bilateral breast MRI technology.

[0005] Currently, several metamaterial resonators for bimammary MRI, such as ultra-high dielectric constant ceramic resonators and orthogonal coil resonators, exist. These technologies improve the radio frequency field and signal-to-noise ratio to some extent, but limitations remain. First, while orthogonal coil resonators can achieve circular polarization and enhance signal reception, their design is complex, typically consisting of two linearly polarized resonators. In bimammary MRI, this means a combination of four resonators is required, increasing system complexity and operational inconvenience. Tuning multiple resonators is relatively difficult and may lead to inconsistent parameter settings, affecting imaging quality and diagnostic accuracy. Although ultra-high dielectric constant ceramic resonators theoretically improve signal strength and imaging quality, their practical acquisition and use present numerous challenges. High-quality ultra-high dielectric constant ceramic materials are not only expensive but also difficult to obtain, limiting their application. Furthermore, these ceramic materials have poor thermal stability, are susceptible to performance degradation due to temperature changes, and their fragility makes them prone to breakage during operation, affecting the long-term use and reliability of MRI equipment.

[0006] Another crucial point is that metamaterials should be used in pairs for bilateral MRI. However, common breast lesions often initially appear only in one breast. When physicians discover a suspicious lesion in one breast during a bilateral breast examination, they want to focus on that area for further pathological analysis. However, current metamaterial-enhanced radiofrequency magnetic fields essentially redistribute the radiofrequency energy generated by the body coil across the entire space, focusing the strong radiofrequency magnetic field near the body coil onto the region of interest. Since the radiofrequency energy generated by the body coil is determined by the excitation power, using metamaterial resonators simultaneously on both breasts results in a larger focused area for radiofrequency energy, weakening the radiofrequency energy allocated to each individual breast and consequently reducing the signal-to-noise ratio. Therefore, integrated bilateral metamaterials cannot help MRI focus on lesions in one breast. Summary of the Invention

[0007] The purpose of this invention is to provide a circularly polarized intelligent metamaterial radio frequency intensifier for magnetic resonance imaging and a dual-mammary magnetic resonance imaging system including the circularly polarized intelligent metamaterial radio frequency intensifier. The aforementioned circularly polarized intelligent metamaterial radio frequency intensifier can realize the enhancement of the circularly polarized radio frequency magnetic field and has the ability to switch between unilateral and bilateral breast imaging modes. The material is readily available and low in cost, and the structure is simple, which can significantly improve the performance of dual-mammary MRI, thereby solving the problems existing in the aforementioned dual-mammary MRI metamaterial resonators.

[0008] To achieve the above objectives, the present invention provides the following solution:

[0009] This invention provides a circularly polarized intelligent metamaterial radio frequency enhancer, comprising a hollow cylindrical dielectric substrate, conductor rings, conductor connectors, and an adjustable capacitor, wherein: a plurality of conductor rings are fitted around the outer ring of the hollow cylindrical dielectric substrate along its axial direction; each conductor ring has an opening in its circumferential direction, and the adjustable capacitor is disposed within the opening of each conductor ring; any two adjacent conductor rings are electrically connected through the conductor connectors.

[0010] In some embodiments, any two adjacent conductor rings are arranged axially spaced on the hollow cylindrical dielectric substrate, forming a guide ring axial gap.

[0011] In some embodiments, the axial spacing of all the guide rings may be exactly the same, completely different, or not exactly the same.

[0012] In some embodiments, the hollow cylindrical dielectric substrate is a cylindrical dielectric substrate or a prismatic dielectric substrate; any one of the conductor rings is a circular ring, an elliptical ring, or a polygonal ring.

[0013] In some embodiments, the hollow cylindrical dielectric substrate is a cylindrical dielectric substrate, any one of the conductor rings is a circular ring, and any one of the conductor rings (12) is fixedly fitted onto the outside of the hollow cylindrical dielectric substrate (11). 。

[0014] In some embodiments, any one of the conductor rings is fixed to the outer wall of the hollow cylindrical dielectric substrate by an interference fit.

[0015] In some embodiments, each of the conductor rings has two openings spaced apart, and the two openings are arranged symmetrically at 180°, with the openings of all the conductor rings axially aligned.

[0016] In some embodiments, the conductor connector is a conductor post, which is parallel to the axial direction of the hollow cylindrical dielectric substrate, and the conductor post passes through all the conductor rings in sequence to achieve a connection between any two adjacent conductor rings.

[0017] In some embodiments, two conductor pillars are provided, arranged symmetrically at 180°, and the line connecting the two conductor pillars is perpendicular to the line connecting the two rows of openings on the cross-section of the cylindrical dielectric substrate.

[0018] In some implementations, the adjustable capacitor is a digital capacitor.

[0019] The present invention also proposes a dual-mast magnetic resonance imaging system, including a radio frequency coil and an electromagnetic shielding layer disposed outside the radio frequency coil, and further including a pair of circularly polarized smart metamaterial radio frequency intensifiers as described in any of the above claims, wherein the pair of circularly polarized smart metamaterial radio frequency intensifiers are arranged at an interval at the center of the radio frequency coil, and the axial direction of any one of the circularly polarized smart metamaterial radio frequency intensifiers is perpendicular to the axial direction of the radio frequency coil.

[0020] The present invention achieves the following technical effects compared to the prior art:

[0021] The circularly polarized intelligent metamaterial RF intensifier proposed in this invention achieves integrated circular polarization enhancement of the RF magnetic field. It uses a single circularly polarized intelligent metamaterial RF intensifier instead of two separate linearly polarized metamaterial RF intensifiers to achieve circular polarization enhancement of the RF magnetic field, overcoming the poor performance of traditional metamaterials that only enhance the linear RF magnetic field and the cumbersome nature of multi-coil combinations. An open conductor ring and an adjustable capacitor are primarily used to enhance the linear polarization of the axial RF magnetic field of the RF coil, while the linear polarization enhancement of the lateral RF magnetic field is achieved by conductor posts connected to the conductor ring. This simple and unified structure, in addition to its excellent magnetic field enhancement effect, also offers advantages such as low manufacturing cost and easy installation. The design of the circularly polarized intelligent metamaterial RF intensifier effectively enhances the strength and concentration of the RF magnetic field, thereby significantly improving the imaging signal-to-noise ratio.

[0022] This invention utilizes the application of adjustable capacitors for intelligent tuning. By adjusting the capacitance values ​​of each capacitor through digital signals, the resonant frequency of the circularly polarized intelligent metamaterial radio frequency enhancer can be changed. This ensures that the circularly polarized intelligent metamaterial radio frequency enhancer remains in the optimal resonant mode during use, i.e., the resonant frequency is consistent with the Larmor frequency. This achieves the highest imaging signal-to-noise ratio gain, resulting in the best improvement in image quality, which is beneficial for practical medical diagnosis.

[0023] Furthermore, this invention employs adjustable capacitor intelligent tuning technology, enabling paired circularly polarized intelligent metamaterial radio frequency intensifiers to flexibly and intelligently switch between unilateral (single breast) and bilateral (bilateral breast) imaging modes. Specifically, in bilateral (bilateral breast) imaging mode, the digital capacitance of the bilateral circularly polarized intelligent metamaterial radio frequency intensifiers 1 is intelligently adjusted to match the resonant frequency of the bilateral circularly polarized intelligent metamaterial radio frequency intensifiers with the Larmor frequency of the MRI system. This significantly enhances the radio frequency magnetic field in the breast region within the cavity of the bilateral circularly polarized intelligent metamaterial radio frequency intensifiers. To switch to unilateral (single breast) imaging mode, the digital capacitance of the circularly polarized intelligent metamaterial radio frequency intensifier on the side requiring focused imaging is adjusted to match the resonant frequency of that side's circularly polarized intelligent metamaterial radio frequency intensifier 1 with the Larmor frequency of the MRI system. Simultaneously, the digital capacitance of the other circularly polarized intelligent metamaterial radio frequency intensifier is adjusted to detune it. This results in a more significant enhancement of the radio frequency magnetic field in the breast region within the cavity of only one circularly polarized intelligent metamaterial radio frequency intensifier, while the other side receives almost no enhancement. This design allows medical personnel to easily select the target area for focused imaging when detecting suspicious lesions, improving detection efficiency and accuracy. This flexible imaging mode switching enhances the device's applicability and meets diverse clinical needs.

[0024] Based on the above technical features, the circularly polarized intelligent metamaterial radio frequency intensifier of the present invention has the characteristics of circularly polarized radio frequency magnetic field enhancement, dynamic tuning, flexible switching between unilateral and bilateral breast imaging modes, readily available and usable materials, and simple structure. It will exhibit excellent performance in bilateral breast MRI imaging, providing higher imaging quality and ease of operation, and has broad clinical application potential, which can promote its more effective application in the field of MRI.

[0025] The dual-mast magnetic resonance imaging system proposed in this invention includes the aforementioned circularly polarized intelligent metamaterial radio frequency intensifier and possesses all the features of the aforementioned circularly polarized intelligent metamaterial radio frequency intensifier, which will not be repeated here. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 is a perspective view of a circularly polarized smart metamaterial radio frequency enhancer disclosed in one or more embodiments;

[0028] Figure 2 is a schematic diagram (top view) of the circularly polarized smart metamaterial radio frequency enhancer in Figure 1;

[0029] Figure 3 is a front view of Figure 2;

[0030] Figure 4 is a side view of Figure 2;

[0031] Figure 5 is a schematic diagram of the structure of the radio frequency coil and shielding layer in a dual-mast magnetic resonance imaging system;

[0032] Figure 6 is a schematic diagram of the structure of the human body model in the radio frequency coil;

[0033] Figure 7 is a schematic diagram of a pair of circularly polarized smart metamaterial radiofrequency intensifiers used in bilateral breast MRI.

[0034] Figure 8 shows the relationship between the intensity and frequency of the radio frequency field generated in the radio frequency coil when there is no circularly polarized smart metamaterial radio frequency enhancer.

[0035] Figure 9 shows the relationship between the intensity of the radio frequency field generated in the radio frequency coil and the frequency when there is a circularly polarized smart metamaterial radio frequency enhancer.

[0036] Figure 10 shows the radio frequency field distribution of the magnetic resonance imaging system without a circularly polarized intelligent metamaterial radio frequency intensifier.

[0037] Figure 11 shows the radio frequency field distribution of a magnetic resonance imaging system with circularly polarized smart metamaterial radio frequency intensifiers and a pair of circularly polarized smart metamaterial radio frequency intensifiers in a bilateral (bimammary) mode.

[0038] Figure 12 shows the radio frequency field distribution of a magnetic resonance imaging system with circularly polarized smart metamaterial radio frequency intensifiers and a pair of circularly polarized smart metamaterial radio frequency intensifiers in unilateral (single emulsion) mode.

[0039] In the figure, the attached labels are as follows: 1. Circularly polarized intelligent metamaterial radio frequency enhancer; 11. Hollow cylindrical dielectric substrate; 12. Conductor ring; 121. Opening; 13. Conductor connector; 14. Adjustable capacitor; 2. Dual-mast magnetic resonance imaging system; 3. Radio frequency coil; 31. End ring; 32. Horizontal bar; 33. Excitation port; 4. Electromagnetic shielding layer; 5. Human body model. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] One objective of this invention is to provide a circularly polarized intelligent metamaterial radio frequency intensifier for magnetic resonance imaging. This circularly polarized intelligent metamaterial radio frequency intensifier can achieve circularly polarized radio frequency magnetic field enhancement and has the ability to switch between unilateral and bilateral breast imaging modes. The material is readily available, low in cost, and has a simple structure, which can significantly improve the performance of bilateral breast MRI, thereby solving the problems existing in the above-mentioned existing bilateral breast MRI metamaterial resonators.

[0042] Another objective of this invention is to provide a dual-mast magnetic resonance imaging system comprising the aforementioned circularly polarized intelligent metamaterial radio frequency intensifier. The aforementioned circularly polarized intelligent metamaterial radio frequency intensifier can achieve circularly polarized radio frequency magnetic field enhancement and has the ability to switch between unilateral and bilateral breast imaging modes. The material is readily available, low in cost, and has a simple structure, which can significantly improve the performance of dual-mast MRI, thereby solving the problems existing in the aforementioned dual-mast MRI metamaterial resonators.

[0043] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0044] Example 1

[0045] As shown in Figures 1 to 4, this embodiment provides a circularly polarized intelligent metamaterial radio frequency enhancer 1, which includes a hollow cylindrical dielectric substrate 11, conductor rings 12, conductor connectors 13, and adjustable capacitors 14. Multiple conductor rings 12 are fitted around the outer circumference of the hollow cylindrical dielectric substrate 11 along its axial direction. Each conductor ring 12 has an opening 121 (i.e., a disconnected position) in its circumferential direction, and an adjustable capacitor 14 is disposed within the opening 121 of each conductor ring 12. Any two adjacent conductor rings 12 are connected by conductor connectors 13. This radio frequency enhancer uses metamaterial technology to replace traditional ceramics and electromagnetic coils, and has the ability to be seamlessly integrated into practical medical environments. Its structural design utilizes a conductor ring 12 with an opening 121, an adjustable capacitor 14, and a conductor connector 13, meticulously combined to form a loop structure sensitive to two orthogonal linearly polarized magnetic field components simultaneously. This design achieves circular polarization enhancement of the radio frequency magnetic field, not only improving the signal-to-noise ratio of the region of interest but also avoiding the complexity of traditional linear resonator combinations. To meet the basic requirements of dual-mastoma magnetic resonance imaging, the aforementioned circularly polarized intelligent metamaterial radio frequency intensifier 1 is generally used in pairs in breast MRI systems. Simultaneously, through the intelligent tunability of the adjustable capacitor 14, the entire circularly polarized intelligent metamaterial radio frequency intensifier 1 allows for rapid adjustment of the capacitance value according to specific imaging needs, enabling the breast MRI system to maintain optimal resonance under different conditions, further improving imaging quality and flexibility. Furthermore, the design of the adjustable capacitor 14 also enables the aforementioned circularly polarized intelligent metamaterial radio frequency intensifier 1 to flexibly switch between single-sided (single-mastoma) and dual-sided (dual-mastoma) imaging modes, allowing the selection of imaging modes based on actual needs without altering its mechanical structure and relative positions. A pair of circularly polarized intelligent metamaterial radio frequency intensifiers 1 correspond to the positions of the two breasts in the human body in a breast magnetic resonance imaging system. In the bilateral (bi-breast) imaging mode, it can image both breasts simultaneously with a high signal-to-noise ratio. In the unilateral (single-breast) mode, the signal-to-noise ratio is further improved, making it suitable for detailed examination of suspicious lesions in one breast.

[0046] In some embodiments, any two adjacent conductor rings 12 are spaced apart axially on the hollow cylindrical dielectric substrate 11, forming axial spacing between the guide rings. In practical applications, the axial spacing between all guide rings can be completely identical, completely different, or not completely identical. Completely different or not completely different refers to the conductor rings 12 being arranged at non-equidistant intervals on the hollow cylindrical dielectric substrate 11. Specifically: when using completely different arrangements, the axial spacing between the guide rings can increase or decrease regularly along the axial direction of the hollow cylindrical dielectric substrate 11, such as arithmetic progression. When using not completely identical arrangements, some continuous guide rings can have the same axial spacing, while the remaining guide rings have different axial spacings, or two types of guide ring axial spacing can be used, with the two types of guide ring axial spacing arranged axially between the hollow cylindrical dielectric substrate 11. The above-mentioned forms of setting the axial spacing between the guide rings are diverse and can be configured into different layout modes according to requirements.

[0047] In some embodiments, the hollow cylindrical dielectric substrate 11 can be a cylindrical dielectric substrate or a prismatic dielectric substrate. The prismatic dielectric substrate can be, but is not limited to, a regular square prism dielectric substrate, a triangular prism dielectric substrate, or a hexagonal prism dielectric substrate. Correspondingly, any conductor ring 12 can be a circular ring, an elliptical ring, or a polygonal ring. The polygonal ring can be, but is not limited to, a triangle, a quadrilateral, or a pentagon. The hollow cylindrical dielectric substrate 11 and the conductor ring 12 can be randomly combined. For example, when the hollow cylindrical dielectric substrate 11 is a cylindrical dielectric substrate, the conductor ring 12 can be a circular ring, an elliptical ring, or a polygonal ring; or when the hollow cylindrical dielectric substrate 11 is a prismatic dielectric substrate, the conductor ring 12 can also be a circular ring, an elliptical ring, or a polygonal ring. All the conductor rings 12 on the hollow cylindrical dielectric substrate 11 can have the same shape, be completely different, or not completely the same shape. Generally, they are all the same shape, for example, all the conductor rings 12 are circular rings or rectangular rings. Regardless of the combination method used, the hollow cylindrical dielectric substrate 11 and the conductor ring 12 can be fixed by means of bonding or friction contact, but not limited to bonding. Taking friction contact as an example, the conductor ring 12 has multiple points that can be interference-fitted with the outer wall of the hollow cylindrical dielectric substrate 11, so the position of the conductor ring 12 on the hollow cylindrical dielectric substrate 11 can be fixed by the friction contact between the two.

[0048] In some specific embodiments, the hollow cylindrical dielectric substrate 11 is preferably a cylindrical dielectric substrate, and any conductor ring 12 is a circular ring. The inner diameter of any conductor ring 12 is preferably designed to be the same as the outer diameter of the hollow cylindrical dielectric substrate 11, so that any conductor ring 12 is fixed to the outer wall of the hollow cylindrical dielectric substrate 11 with an interference fit. Simultaneously, the conductor rings 12 are preferably arranged at equal intervals along the axial direction of the hollow cylindrical dielectric substrate 11 (i.e., all guide rings have the same axial spacing).

[0049] In some embodiments, multiple openings 121 may be spaced apart on any conductor ring 12. Specifically, as shown in Figures 1 to 4, taking any conductor ring 12 as a circular ring as an example, two openings 121 are spaced apart on any conductor ring 12, and the two openings 121 are arranged symmetrically at 180°. The openings 121 of all conductor rings 12 are axially aligned, thereby forming two rows of openings 121 symmetrically on both sides of all conductor rings 12. Based on this, the conductor connector 13 can preferably be a conductor post, which is parallel to the axial direction of the hollow cylindrical dielectric substrate 11, and the conductor post passes through all conductor rings 12 in sequence, thereby realizing the connection between any two adjacent conductor rings 12. As shown in Figures 1 to 4, two conductor posts can be provided, which are arranged symmetrically at 180°. On the cross-section of the cylindrical dielectric substrate, the line connecting the two conductor posts is perpendicular to the line connecting the two rows of openings 121.

[0050] In some embodiments, the conductor post can be integrally formed with the half-ring of each conductor ring 12, for example, by integrally cutting it into copper. Alternatively, the conductor post can be assembled and connected with the half-ring of each conductor ring 12. Specifically, each half-ring of the conductor ring 12 has a through hole, through which the conductor post passes and is welded to the conductor ring 12.

[0051] The working principle of the circularly polarized intelligent metamaterial radio frequency enhancer 1 is as follows: Several layers of conductor rings 12 with openings 121 are installed on a hollow cylindrical dielectric substrate 11. The conductor rings 12, stacked longitudinally (i.e., along the axial direction of the hollow cylindrical dielectric substrate 11), can interact with the magnetic field component polarized along the central axial direction of the conductor rings 12. When the magnetic field component polarized along the central axial direction of the conductor rings 12 is excited by the magnetic field at its resonant frequency, an induced circulating current is distributed along each layer of conductor rings 12, resulting in a local magnetic field resonance enhancement at the center of the conductor rings 12; the symmetrical sides of the portion of the conductor rings 12 without openings 121 are distributed... A conductor post is connected through the conductor ring 12. These two conductor posts and each layer of conductor ring 12 form a longitudinal loop. Similar to the conductor ring 12's induction of the magnetic field, this loop can interact with the magnetic field component perpendicular to the polarization sensitive direction of the conductor ring 12. In MRI, the radio frequency coil 3, such as the birdcage coil, generates transverse magnetic fields for both transmission and reception. It is circularly polarized around the static magnetic field B0. The circularly polarized radio frequency magnetic field can be decomposed into two mutually perpendicular linearly polarized magnetic field components, x and y, which can be excited by the circularly polarized smart metamaterial radio frequency enhancer 1.

[0052] The aforementioned circularly polarized smart metamaterial radio frequency intensifier 1 must be used in pairs for dual-mast magnetic resonance imaging.

[0053] In some embodiments, the two poles of the adjustable capacitor 14 are electrically connected to the two ends of the corresponding opening 121. In practical applications, a fixing scheme in which the two poles of the adjustable capacitor 14 are welded to the two ends of the corresponding opening 121 can be adopted.

[0054] In some embodiments, the adjustable capacitor 14 is preferably a digital capacitor. A digital capacitor, also known as a digital capacitor, allows for intelligent tunability, enabling rapid adjustment of its capacitance value according to specific imaging needs. This allows the magnetic resonance imaging system to maintain optimal resonance under different conditions, further improving imaging quality and flexibility. Furthermore, the digital capacitor provides the entire RF intensifier with flexible single-sided (single-epithelial) and dual-sided (dual-epithelial) imaging mode switching capabilities, allowing the selection of imaging modes based on actual requirements without altering the mechanical structure and relative positions of the RF intensifier. Specifically, in bilateral (bilateral breast) imaging mode, the digital capacitance of the bilateral circularly polarized intelligent metamaterial radiofrequency intensifier 1 is intelligently adjusted to match the resonant frequency of the bilateral circularly polarized intelligent metamaterial radiofrequency intensifier 1 with the Larmor frequency of the MRI system. This significantly enhances the radiofrequency magnetic field in the breast region within the cavity of the bilateral circularly polarized intelligent metamaterial radiofrequency intensifier 1. To switch to unilateral (single breast) imaging mode, the digital capacitance of the circularly polarized intelligent metamaterial radiofrequency intensifier 1 on the side requiring focused imaging is adjusted to match its resonant frequency with the Larmor frequency of the MRI system. Simultaneously, the digital capacitance of the other circularly polarized intelligent metamaterial radiofrequency intensifier 1 is adjusted to detune it. This results in a more significant enhancement of the radiofrequency magnetic field in the breast region within the cavity of only one circularly polarized intelligent metamaterial radiofrequency intensifier 1, while the other side receives almost no enhancement. This design allows medical personnel to easily select the target imaging area when detecting suspicious lesions, improving detection efficiency and accuracy. This flexible imaging mode switching enhances the applicability of the device and meets different clinical needs.

[0055] The following example demonstrates the working principle and technical effect of the circularly polarized intelligent metamaterial radio frequency enhancer 1 described above in this embodiment by modeling and simulating a dual-mast magnetic resonance imaging system 2 in professional electromagnetic simulation software.

[0056] In the circularly polarized intelligent metamaterial radio frequency enhancer 1: any conductor ring 12 is a copper ring formed by bending a solid copper tube. The cross-sectional radius of the solid copper tube is 1.9 mm, the inner diameter of the conductor ring 12 is 144.2 mm, and the opening 121 is a fan-shaped notch with a minimum interval of 4 mm; the hollow cylindrical dielectric substrate 11 is preferably made of insulating material, such as, but not limited to, acrylic sheet. The outer diameter of the hollow cylindrical dielectric substrate 11 is 144.2 mm, and the inner diameter is 138.2 mm. A total of 13 layers of conductor rings 12 are sleeved on the hollow cylindrical dielectric substrate 11. The axial interval between any two adjacent conductor rings 12 is 9 mm. Any conductor ring 12 can be directly interference-fitted with the hollow cylindrical dielectric substrate 11, or interference-fitted and then bonded; the conductor column is preferably a solid copper column with an axial length of 111.8 mm and a cross-sectional radius of 1.36 mm.

[0057] The aforementioned circularly polarized smart metamaterial radio frequency enhancer 1 is used in pairs.

[0058] The static magnetic field of the dual-mast magnetic resonance imaging system 2 is 1.5T, and the corresponding Larmor frequency of hydrogen protons is 63.8MHz, which is the resonant frequency of the designed circularly polarized intelligent metamaterial radio frequency enhancer 1.

[0059] A birdcage coil is used as the radio frequency coil 3 of the dual-mast magnetic resonance imaging system 2. As shown in Figure 5, the birdcage coil consists of two end rings 31 made of conductor and several crossbars 32. An electromagnetic shielding layer 4 is provided on the outer periphery of the birdcage coil. Two excitation ports 33 with a phase difference of 90° are set on the birdcage coil to generate a circularly polarized radio frequency magnetic field through orthogonal excitation. Using a magnetic field probe located at the geometric center of the birdcage coil, it was observed that the dual-mast magnetic resonance imaging system 2 with the non-circularly polarized intelligent metamaterial radio frequency intensifier 1 operates at 63.8MHz, as shown in Figure 8. The numerically calculated spectrum of the magnetic field probe shows that the peak values ​​of the x and y components of the magnetic field intensity are both at a frequency of 63.8MHz, and the peak intensities of the x and y components are both approximately 0.3A / m. This indicates that the radio frequency magnetic field excited by the birdcage coil is circularly polarized, and the resonant frequency is 63.8MHz.

[0060] When a pair of circularly polarized smart metamaterial RF enhancers 1 are placed at the exact center of the birdcage coil, as shown in Figure 7, the capacitance value of each adjustable capacitor 14 in the pair of circularly polarized smart metamaterial RF enhancers 1 is adjusted to 7.95 pF. Using a magnetic field probe located at the geometric center of the birdcage coil, as shown in Figure 9, the numerically calculated spectrum of the magnetic field probe shows that the peak values ​​of both the x and y components of the magnetic field strength are at a frequency of 63.8 MHz, and the peak intensities of both the x and y components are approximately 10 A / m. Therefore, the central magnetic field strength is significantly enhanced in both the x and y components. This indicates that the circularly polarized smart metamaterial RF enhancer 1 can enhance all components of the circularly polarized magnetic field generated by the birdcage coil, making full use of the RF power, and the resonant frequency of the circularly polarized smart metamaterial RF enhancer 1 is matched with that of the birdcage coil at 63.8 MHz.

[0061] A female human model 5 was placed at the center of a birdcage coil to form a dual-mammary MRI system without metamaterials, as shown in Figure 6. The radio frequency field distribution at the longitudinal section of the center of the human breast model was observed without the circularly polarized intelligent metamaterial radio frequency intensifier 1 inside the birdcage coil, as shown in Figure 10.

[0062] Based on a bilateral breast MRI system without circularly polarized intelligent metamaterial radio frequency intensifiers 1, a pair of circularly polarized intelligent metamaterial radio frequency intensifiers 1 were introduced and positioned near the bilateral breasts of the human model 5. The excitation port 33 of the birdcage coil was used as the excitation source. When using the bilateral (bilateral breast) imaging mode, the capacitance value of each adjustable capacitor 14 in the pair of circularly polarized intelligent metamaterial radio frequency intensifiers 1 was adjusted to 7.48 pF. When using the unilateral (unilateral breast) imaging mode, the capacitance value of each adjustable capacitor 14 in the detuned side of the circularly polarized intelligent metamaterial radio frequency intensifier 1 was adjusted to 3 pF, while the capacitance value of each adjustable capacitor 14 in the normally functioning side of the circularly polarized intelligent metamaterial radio frequency intensifier 1 was 8 pF. As shown in Figure 7, the radio frequency field distribution of the longitudinal section at the center of the human model 5 with the circularly polarized intelligent metamaterial radio frequency intensifiers 1 was observed. The radio frequency field distributions in the bilateral and unilateral imaging modes using the circularly polarized intelligent metamaterial radio frequency intensifiers 1 are shown in Figures 11 and 12, respectively.

[0063] Comparing Figure 10 with Figures 11 and 12, it can be seen that: without the circularly polarized intelligent metamaterial radio frequency intensifier 1, the radio frequency field distribution within the birdcage coil is uniform, with higher intensity near the edge of the coil conductor; with the circularly polarized intelligent metamaterial radio frequency intensifier 1, regardless of whether the circularly polarized intelligent metamaterial radio frequency intensifier 1 is in bilateral or unilateral imaging mode, the radio frequency field intensity within the cavity of the circularly polarized intelligent metamaterial radio frequency intensifier 1 is significantly increased, while the radio frequency field intensity outside the structure of the circularly polarized intelligent metamaterial radio frequency intensifier 1 is weaker; selecting one breast model as the imaging region, when the circularly polarized intelligent metamaterial radio frequency intensifier 1 is in unilateral (single breast) imaging mode, compared with bilateral (bilateral) imaging mode, the radio frequency field intensity of the unilateral breast region is higher. The area within the white dashed line of the breast model in Figures 10, 11, and 12 was selected as the target area for radio frequency field enhancement. It was calculated that within the target area, the radio frequency field intensity of the bilateral (bi-breast) imaging mode using the circularly polarized intelligent metamaterial radio frequency enhancer 1 was 10.6 times that without the circularly polarized intelligent metamaterial radio frequency enhancer 1, and the radio frequency field intensity of the unilateral imaging mode using the circularly polarized intelligent metamaterial radio frequency enhancer 1 was 16.9 times that of the unilateral breast area without the circularly polarized intelligent metamaterial radio frequency enhancer 1.

[0064] Therefore, the circularly polarized intelligent metamaterial RF intensifier 1 proposed in this scheme achieves integrated circular polarization enhancement of the RF magnetic field. It achieves circular polarization enhancement of the RF magnetic field through a single circularly polarized intelligent metamaterial RF intensifier 1 instead of two separate linearly polarized metamaterial RF intensifiers, overcoming the poor effect of traditional metamaterials that only enhance the linear RF magnetic field and the cumbersome nature of multi-coil combinations. The open conductor ring and adjustable capacitor are mainly used to enhance the linear polarization of the axial RF magnetic field of the RF coil, while the linear polarization enhancement of the lateral RF magnetic field of the RF coil is achieved by conductor posts connected to the conductor ring. This simple and unified structure, in addition to its excellent magnetic field enhancement effect, also has advantages such as low manufacturing cost and easy installation. The design of the circularly polarized intelligent metamaterial RF intensifier 1 effectively enhances the strength and concentration of the RF magnetic field, thereby significantly improving the imaging signal-to-noise ratio.

[0065] This solution utilizes intelligent tunable digital capacitors to adjust the capacitance values ​​of each capacitor via digital signals, thereby altering the resonant frequency of the circularly polarized intelligent metamaterial RF intensifier 1. This ensures that the RF intensifier 1 remains in its optimal resonant mode during operation, aligning with the Larmor frequency. This achieves the highest possible imaging signal-to-noise ratio gain, resulting in significantly improved image quality and facilitating practical medical diagnosis. During use, each digital capacitor is connected to the controller, enabling the RF intensifier 1 to perform real-time dynamic tuning during actual magnetic resonance imaging, ensuring it remains in its optimal resonant mode and maximizing the imaging signal-to-noise ratio gain.

[0066] Furthermore, this solution employs digital capacitor intelligent tunable technology, enabling the paired circularly polarized intelligent metamaterial radio frequency intensifiers 1 to flexibly and intelligently switch between unilateral (single breast) and bilateral (bilateral breast) imaging modes. Specifically, in bilateral (bilateral breast) imaging mode, the digital capacitance of the bilateral circularly polarized intelligent metamaterial radio frequency intensifiers 1 is intelligently adjusted to match the resonant frequency of the bilateral circularly polarized intelligent metamaterial radio frequency intensifiers 1 with the Larmor frequency of the MRI system. This significantly enhances the radio frequency magnetic field in the breast region within the cavity of the bilateral circularly polarized intelligent metamaterial radio frequency intensifiers 1. To switch to unilateral (single breast) imaging mode, the digital capacitance of the circularly polarized intelligent metamaterial radio frequency intensifier 1 on the side requiring focused imaging is adjusted to match its resonant frequency with the Larmor frequency of the MRI system. Simultaneously, the digital capacitance of the other circularly polarized intelligent metamaterial radio frequency intensifier 1 is adjusted to detune it. This results in a more significant enhancement of the radio frequency magnetic field in the breast region within the cavity of only one circularly polarized intelligent metamaterial radio frequency intensifier 1, while the other side receives almost no enhancement. This design allows medical personnel to easily select the target area for focused imaging when detecting suspicious lesions, improving detection efficiency and accuracy. This flexible imaging mode switching enhances the device's applicability and meets diverse clinical needs.

[0067] Based on the above technical features, the circularly polarized intelligent metamaterial radiofrequency intensifier 1 proposed in this solution will exhibit excellent performance in bilateral breast MRI imaging, providing higher imaging quality and ease of operation, and has broad clinical application potential.

[0068] It should be noted that the aforementioned RF coil 3 can also be replaced with other RF coils capable of generating circularly polarized RF magnetic fields, excluding the birdcage coil. The human body model 5 used can be replaced with any voxel model; the conductor rings and conductor pillars can be replaced with conductors other than annealed copper; the dielectric substrate material can be replaced with other dielectrics besides acrylic sheets; the openings on each conductor ring can be in any position, and correspondingly, the conductor pillars and adjustable capacitors can have arbitrary relative positions while maintaining a basic connection with the conductor rings; the application site of the entire circularly polarized intelligent metamaterial RF enhancer 1 can be replaced with other human body parts besides the breast. After being moved to other locations, the circularly polarized intelligent metamaterial RF enhancer 1 still has the effect of enhancing the RF field, and the enhancement amplitude of the RF field can achieve an effect similar to or better than the above scheme.

[0069] Example 2

[0070] As shown in Figures 5-7, this embodiment proposes a dual-mast magnetic resonance imaging system 2, including a radio frequency coil 3 and an electromagnetic shielding layer 4 disposed outside the radio frequency coil 3. The radio frequency coil 3 is used to generate a circularly polarized radio frequency magnetic field. As shown in Figures 5 and 7, the dual-mast magnetic resonance imaging system 2 also includes a pair of circularly polarized intelligent metamaterial radio frequency intensifiers 1 as disclosed in Embodiment 1. The pair of circularly polarized intelligent metamaterial radio frequency intensifiers 1 are arranged radially at intervals at the center of the radio frequency coil 3, and the pair of circularly polarized intelligent metamaterial radio frequency intensifiers 1 correspond to the positions of the two breasts of the human body. The axial direction of any one of the circularly polarized intelligent metamaterial radio frequency intensifiers 1 is perpendicular to the axial direction of the radio frequency coil 3, as shown in Figure 7.

[0071] The operating principle and effects of the above-mentioned dual-mast magnetic resonance imaging system 2 can be found in Example 1, and will not be repeated here.

[0072] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A circularly polarized intelligent metamaterial radio frequency enhancer, characterized in that, It includes a hollow cylindrical dielectric substrate (11), a conductor ring (12), a conductor connector (13), and an adjustable capacitor (14), wherein: The outer ring of the hollow cylindrical dielectric substrate (11) is fitted with a plurality of conductor rings (12) along its axial direction; Each of the conductor rings (12) has an opening (121) in the circumferential direction, and each of the conductor rings (12) has an adjustable capacitor (14) in the opening (121). Any two adjacent conductor rings (12) are electrically connected through the conductor connector (13).

2. The circularly polarized smart metamaterial radio frequency enhancer according to claim 1, characterized in that, Any two adjacent conductor rings (12) are arranged axially on the hollow cylindrical dielectric substrate (11) and form a guide ring axial spacing.

3. The circularly polarized intelligent metamaterial radio frequency enhancer according to claim 2, characterized in that, All of the guide rings may have identical, completely different, or not identical axial spacing.

4. The circularly polarized intelligent metamaterial radio frequency enhancer according to claim 1, characterized in that, The hollow cylindrical dielectric substrate (11) is a cylindrical dielectric substrate or a prismatic dielectric substrate; any one of the conductor rings (12) is a circular ring, an elliptical ring or a polygonal ring.

5. The circularly polarized smart metamaterial radio frequency enhancer according to claim 4, characterized in that, The hollow cylindrical dielectric substrate (11) is a cylindrical dielectric substrate, and any one of the conductor rings (12) is a circular ring, and any one of the conductor rings (12) is fixedly fitted on the outside of the hollow cylindrical dielectric substrate (11).

6. The circularly polarized smart metamaterial radio frequency enhancer according to claim 5, characterized in that, Two openings (121) are spaced apart on any one of the conductor rings (12), and the two openings (121) are arranged symmetrically at 180°. The openings (121) of all the conductor rings (12) are axially aligned.

7. The circularly polarized smart metamaterial radio frequency enhancer according to claim 6, characterized in that, The conductor connector (13) is a conductor post, which is parallel to the axial direction of the hollow columnar dielectric substrate (11) and passes through all the conductor rings (12) in sequence to achieve the connection between any two adjacent conductor rings (12).

8. The circularly polarized smart metamaterial radio frequency enhancer according to claim 7, characterized in that, Two conductor pillars are provided, and the two conductor pillars are arranged symmetrically at 180°. On the cross-section of the cylindrical dielectric substrate, the line connecting the two conductor pillars is perpendicular to the line connecting the two columns of openings (121).

9. The circularly polarized intelligent metamaterial radio frequency enhancer according to claim 1, characterized in that, The adjustable capacitor (14) is a digital capacitor.

10. A dual-mast magnetic resonance imaging system, comprising a radio frequency coil (3) and an electromagnetic shielding layer (4) disposed outside the radio frequency coil (3), characterized in that, It also includes a pair of circularly polarized smart metamaterial radio frequency enhancers (1) as described in any one of claims 1 to 9, wherein the pair of circularly polarized smart metamaterial radio frequency enhancers (1) are arranged radially at the center of the radio frequency coil (3), and the axial direction of any one of the circularly polarized smart metamaterial radio frequency enhancers (1) is perpendicular to the axial direction of the radio frequency coil (3).

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