Coaxial line double-tuning coil structure

Abstract

The utility model discloses a coaxial line double-tuning coil structure, and relates to the technical field of imaging coils. Comprising a coil formed by bending and winding a coaxial line, the coil forms a double-loop structure of an inner conductor and an outer conductor which are coaxially arranged, the outer conductor loop completely wraps the inner conductor loop, a port of the outer conductor loop is electrically connected with an outer layer tuning element, and the inner conductor loop is provided with a feed port used for being connected with a tuning matching circuit. According to the utility model, resonance and coupling of an inner conductor loop and an outer conductor loop are utilized to realize simultaneous resonance imaging of two different frequencies by the single-port coil, so that the multi-nuclide imaging or multi-system imaging requirements are met; and the coil structure is simple in manufacturing process, low in cost and flexible in application scene, and the coil conductor has a flexible coil development prospect.

Description

Technical Field

[0001] This utility model relates to the field of imaging coil technology, specifically a coaxial double-tuned coil structure. Background Technology

[0002] In magnetic resonance imaging (MRI) technology, radio frequency coils are the core components for achieving nuclear spin excitation and signal detection. Traditional MRI systems primarily rely on hydrogen nuclei (… 1 The magnetic resonance signal of hydrogen (H) is highly sensitive because hydrogen nuclei are abundant in the human body and have a high gyromagnetic ratio, allowing MRI to provide high-resolution images. However, with the advancement of medical research and the increase in clinical needs, the demand for multi-element imaging is becoming increasingly urgent. For example, fluorine (… 19 F), carbon ( 13 C) Imaging of different nuclides can provide information about tissue metabolism, function, and structure. When a lesion occurs, the content of these elements will resonate and produce abnormal signals. Combining this with hydrogen nuclear imaging helps doctors to have a more comprehensive understanding of the nature and extent of the lesion.

[0003] Therefore, multi-nucleus imaging technology has improved the sensitivity and specificity of MRI for detecting certain specific lesions. This technological development has also placed new demands on MRI radiofrequency coils. Conventional radiofrequency coils can only image a single hydrogen element; to image other elements, dedicated coils with corresponding resonant frequencies must be used. Therefore, how to design and implement a radiofrequency coil capable of simultaneously imaging two or more elements has become an important issue in multi-nucleus imaging technology. To address this, this invention, based on the aforementioned research background, proposes a dual-tuned radiofrequency coil structure using a coaxial line. Utility Model Content

[0004] The purpose of this invention is to provide a coaxial double-tuned coil structure, which simplifies the double resonant circuit by utilizing the double-layer structure of the coaxial line, and realizes the resonant imaging of two frequency elements or the imaging of two field strength systems with low cost and simple manufacturing process.

[0005] This utility model can be achieved through the following technical solution: a coaxial double-tuned coil structure, including a coil formed by bending and winding a coaxial line. The coil forms a coaxial inner and outer conductor double-circuit structure, and the outer conductor circuit completely wraps the inner conductor circuit. The outer conductor circuit port is electrically connected to an outer layer tuning element, and the inner conductor circuit is provided with a power supply port for connecting a tuning matching circuit.

[0006] A further technical improvement of this utility model is that the coaxial cable includes an outer insulating layer, a shielding layer, an inner insulating layer, and an inner conductor, which are coaxially sleeved from the outside to the inside. The outer conductor circuit is composed of the shielding layer, and the inner conductor circuit is composed of the inner conductor. There is no electrical connection between the outer conductor circuit and the inner conductor circuit. The two achieve dual-frequency resonance through coupling.

[0007] A further technical improvement of this utility model is that the outer tuning element is specifically a tuning capacitor.

[0008] A further technical improvement of this utility model is that a bidirectional diode is connected in parallel on the outer tuning element to achieve passive detuning in the non-operating state.

[0009] A further technical improvement of this utility model is that the tuning matching circuit includes a signal excitation source, a coil matching capacitor, and an inner conductor tuning element. By adjusting the inner conductor tuning element and the outer conductor tuning element, the coil circuit is made to resonate at the target frequency.

[0010] A further technical improvement of this utility model is that the coil structure formed by bending the coaxial line can be adjusted according to the requirements of the imaging part, including a circular ring structure, an elliptical ring structure, and a polygonal structure.

[0011] A further technical improvement of this utility model is that the shielding layer is specifically a mesh structure woven from fine copper wires.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] (1) This utility model utilizes the resonance and coupling of the inner and outer conductor circuits to realize the simultaneous imaging of two different frequencies by a single-port coil, thus meeting the requirements of multi-nucleus imaging or multi-system imaging.

[0014] (2) The coil structure mentioned in this utility model has a simple manufacturing process, low cost, flexible application scenarios, and the coil conductor has the development prospects of flexible coil. Attached Figure Description

[0015] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0016] Figure 1 This is a cross-sectional view of the coaxial line structure of this utility model;

[0017] Figure 2 This is a schematic diagram of the conductor circuit in the case of omitting the insulation layer in this utility model;

[0018] Figure 3 This is a schematic diagram of the CST field-circuit joint simulation loop of this utility model;

[0019] Figure 4This utility model is based on Figure 3 Electromagnetic simulation results of the circuit loop.

[0020] In the diagram: 1. Outer insulating layer; 2. Shielding layer; 3. Inner insulating layer; 4. Inner conductor; 5. Outer resonant capacitor; 6. Bidirectional diode; 7. Power supply port. Detailed Implementation

[0021] To further illustrate the technical means and effects adopted by this utility model in order to achieve the intended utility model purpose, the following detailed description of the specific implementation methods, structure, features and effects of this utility model is provided in conjunction with the accompanying drawings and preferred embodiments.

[0022] Please see Figure 1 As shown, a coaxial double-tuned coil structure includes an outer insulating layer 1, a shielding layer 2, an inner insulating layer 3, and an inner conductor 4, which are coaxially arranged from the outside to the inside. The shielding layer 2 is made of fine copper wire woven into a mesh structure.

[0023] like Figure 2 As shown, the outer insulating layer 1 and the inner insulating layer 3 are omitted. The coaxial line is wrapped into a ring-shaped flexible coil structure. The coil structure is not limited to a circular ring structure. Utilizing its flexibility, it can be flexibly wound according to the imaging requirements to improve the fit between the coil and the object being detected.

[0024] A closed loop is formed by a shielding layer 2 and an inner conductor 4, and the outer loop formed by the shielding layer 2 completely encloses the inner loop. An outer tuning capacitor 5 and a bidirectional diode 6 are electrically connected in parallel at the port of the outer loop. The function of the bidirectional diode 6 is to perform passive detuning to ensure that the coil does not resonate during its non-operation period. A feed port 7 is provided in the inner loop, and the feed port 7 is connected to an external tuning matching circuit to form a resonant loop.

[0025] The tuning matching circuit connected to power supply port 7 can take many forms, such as... Figure 3 The simulation circuit shown is a type of circuit where A is the signal excitation source, C1 is the coil matching capacitor, Ct is the inner conductor tuning element, which is connected to the inner conductor port 11' (equivalent to the feed port 7) of the coaxial line structure to form a complete inner resonant circuit; Cd is the outer conductor tuning element, which is connected to the outer conductor port 22' to form an outer resonant circuit.

[0026] It should be noted that by selecting appropriate tuning elements and adjusting their specifications in the inner and outer circuits, the resonant frequency can reach the target frequency. Since the outer circuit completely encloses the inner circuit, the resonance of the outer conductor can induce the inner conductor circuit through coupling. Therefore, although the coil feed port 7 is located in the inner circuit, the actual coil can detect the resonance of two frequencies, thereby realizing the imaging of different elements or different systems.

[0027] The above circuit was used for simulation to verify the results, and the following was obtained. Figure 4 The diagram shows the variation of the entire circuit resonance curve S11 within the range of 0-200MHz. Two distinct resonance peaks can be seen in the figure, located at 14.8MHz and 63.6MHz respectively. This indicates that the coaxial double-tuned coil structure resonates at both frequency points, enabling the reception of signals at the corresponding frequencies. Therefore, the coil structure in this embodiment can be applied to both 0.35T (operating frequency of 14.9MHz) and 1.5T (operating frequency of 63.8MHz) systems.

[0028] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present utility model. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the scope of the present utility model shall still fall within the scope of the present utility model.

Claims

1. A coaxial double-tuned coil structure, characterized in that, It includes a coil formed by bending and winding a coaxial line. The coil forms a double-circuit structure with inner and outer conductors arranged coaxially. The outer conductor circuit completely wraps the inner conductor circuit. The outer conductor circuit port is electrically connected to the outer tuning element. The inner conductor circuit is provided with a power supply port (7) for connecting the tuning matching circuit.

2. The coaxial double-tuned coil structure according to claim 1, characterized in that, The coaxial line includes an outer insulating layer (1), a shielding layer (2), an inner insulating layer (3), and an inner conductor (4) that are coaxially arranged from the outside to the inside. The outer conductor circuit is composed of the shielding layer (2), and the inner conductor circuit is composed of the inner conductor (4). There is no electrical connection between the outer conductor circuit and the inner conductor circuit. The two achieve dual-frequency resonance through coupling.

3. The coaxial double-tuned coil structure according to claim 1, characterized in that, The outer tuning element is specifically a tuning capacitor.

4. The coaxial double-tuned coil structure according to claim 3, characterized in that, A bidirectional diode is connected in parallel with the outer tuning element to achieve passive detuning in the non-operating state.

5. The coaxial double-tuned coil structure according to claim 1, characterized in that, The tuning and matching circuit includes a signal excitation source, a coil matching capacitor, and an inner conductor tuning element. By adjusting the inner conductor tuning element and the outer conductor tuning element, the coil circuit is made to resonate at the target frequency.

6. The coaxial double-tuned coil structure according to claim 1, characterized in that, The coil structure formed by bending the coaxial line can be adjusted according to the requirements of the imaging part, including circular ring structure, elliptical ring structure and polygonal structure.

7. A coaxial double-tuned coil structure according to claim 2, characterized in that, The shielding layer is specifically a mesh structure woven from fine copper wires.

Images