Gradient tuning type exciting coil structure and system for biological electromagnetic stimulation
By designing a multi-layer figure-8 stimulation coil and control module system, the focusing and safety issues in transcranial electromagnetic stimulation technology were solved, and a more efficient bio-electromagnetic stimulation effect was achieved.
Patent Information
- Application Number
- CN202510944544.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-09
- Publication Date
- 2025-10-17
AI Technical Summary
In existing transcranial electromagnetic stimulation technology, the stimulation coil has weak focusing, insufficient stimulation depth, single pulse width and frequency parameter adjustment, and has adverse effects on non-target areas, affecting treatment safety.
A multi-layer 8-shaped stimulation coil is designed. The inner diameter of each coil layer increases gradually and is bilaterally symmetrical. The excitation current is connected through a discharge circuit. Combined with a control module and an energy storage capacitor system, the excitation current is adjusted to improve stimulation focus and safety.
It significantly improves the stimulation focus of the coil, reduces the impact on non-target areas, ensures the effectiveness and safety of the stimulation, and achieves a more efficient bio-electromagnetic stimulation effect.
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Figure CN120789494A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of bioelectromagnetic stimulation, and particularly relates to a gradient tuning type excitation coil structure and system for bioelectromagnetic stimulation. BACKGROUND
[0002] Bio / Transcranial electromagnetic stimulation technology, as a new non-invasive technology for brain disease treatment, is born in cross-disciplines. This technology involves medicine, neuroelectrophysiology and electromagnetism, and provides innovative technical means for the treatment of neurodegenerative diseases and brain function network analysis. In order to reduce the stimulation of non-target regions in the skull and reduce the side effects of stimulation, it is usually necessary to optimize the design of the stimulation coil.
[0003] The most fundamental physical principle of transcranial electromagnetic stimulation is Faraday's electromagnetic induction, that is, a rapidly changing excitation current is passed into the stimulation coil to generate a time-varying magnetic field, and the time-varying magnetic field will generate an induced current in the brain tissue. The induced current generates an induced electric field to stimulate the neural tissue inside the brain, so that the membrane potential of neurons is hyperpolarized or depolarized, thereby producing a series of physiological changes. The treatment effect of transcranial electromagnetic stimulation depends on a large number of parameters, such as stimulation time, stimulation intensity, duration and stimulation current mode. At present, there are still problems such as weak focusing, insufficient stimulation depth, single pulse width and frequency parameter adjustment, and application safety is also a research focus.
[0004] The focusing of the induced electric field of the stimulation coil is a key parameter of transcranial electromagnetic stimulation technology. Through the design and optimization of the geometric structure of the coil, the selection of materials, the spatial arrangement, the study of the distribution of the magnetic field and the induced electric field, and the determination of the stimulation range, the stimulation accuracy of the target area can be effectively improved, the influence on the surrounding non-target area can be reduced, and the risk of inducing diseases can be reduced. At present, most of the researches on the stimulation coil are based on the design of the 8-shaped coil to improve the focusing of the induced electric field. Transcranial electromagnetic stimulation is a technology that generates a strong magnetic field through a strong current through a coil, and uses magnetic field gradient control and focusing positioning technology for stimulation. However, due to the complexity of magnetic field gradient control and positioning control, the coil is overheated by avoiding high-frequency stimulation, and low-frequency stimulation is used, so it is of great significance to realize flexible control of stimulation parameters in application.
[0005] The magnetic stimulation coil is an important carrier for realizing transcranial magnetic stimulation, converting time-varying current into a specific magnetic field, and inducing an electric field, is the core of the whole transcranial electromagnetic stimulation, and is also the difficulty in design, which determines the stimulation intensity, stimulation depth and focusing of the magnetic stimulation. By improving the stimulation focusing of the target area and reducing the stimulation on the non-target area, the occurrence of complications is reduced. The size, shape and material of the coil, the waveform, intensity and frequency of the stimulation current in the coil, the placement position, direction and angle will affect the stimulation effect, and specifically affect the distribution shape, focusing, stimulation depth, stimulation position, equipment energy utilization rate and safety of the induced electric field. Therefore, the design and research of the coil are the key of the technology, and at present, the performance of the stimulation coil is mainly improved from the aspects of the shape structure of the coil, the array design of the coil and the addition of auxiliary materials such as shielding plates.
[0006] In summary, how to propose a gradient tuning type stimulation coil based on the superposition and cancellation of the magnetic field, so as to induce a more concentrated induced electric field, improve the focusing, have more balanced stimulation performance, and weaken the influence on the non-target tissue to the greatest extent under the condition of effectively stimulating the target target point, and ensure the effect and safety of transcranial electromagnetic stimulation treatment, is a subject that needs to be studied by those skilled in the art. SUMMARY
[0007] The purpose of the present application is to provide a gradient tuning type excitation coil structure and a gradient tuning type excitation system for bioelectromagnetic stimulation, to solve the problem of limited electromagnetic stimulation effect of the traditional stimulation coil, and to significantly improve the focusing of the coil stimulation while ensuring the stimulation intensity and the inductance value of the coil, effectively reducing the adverse effects on the non-target area, and ensuring the safety of transcranial electromagnetic stimulation treatment.
[0008] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:
[0009] In a first aspect, a gradient tuning type excitation coil structure for bioelectromagnetic stimulation is provided, comprising a multi-layer 8-shaped stimulation coil for being placed horizontally above a bioelectromagnetic stimulation target target area;
[0010] The inner diameter of each layer of the multi-layer 8-shaped stimulation coil increases layer by layer from bottom to top, and the two coil units in each layer of the multi-layer 8-shaped stimulation coil are left-right symmetrical;
[0011] The multi-layer 8-shaped stimulation coil is used to connect the excitation current through the discharge circuit to play a bioelectromagnetic stimulation effect on the bioelectromagnetic stimulation target target area.
[0012] Based on the above invention, a new stimulation coil design scheme is provided, which can significantly improve the focusing of the coil stimulation while ensuring the stimulation intensity and the inductance value of the coil, that is, a multi-layer 8-shaped stimulation coil is used for being horizontally placed above the bio-electromagnetic stimulation target area, the inner diameter of each layer of the 8-shaped stimulation coil increases layer by layer from bottom to top, and the two coil units in each layer of the 8-shaped stimulation coil are left-right symmetrical, the multi-layer 8-shaped stimulation coil is used for being connected to the excitation current through the discharge circuit to play a bio-electromagnetic stimulation role on the target area, so that the focusing of the target area is significantly improved without losing much induced electric field intensity, the hidden danger caused by too large focusing area is eliminated, a higher electric field intensity is generated at the cerebral cortex, the effectiveness of stimulating the brain is ensured, and the actual application and promotion are facilitated.
[0013] In a possible design, the multi-layer 8-shaped stimulation coil includes a lower layer multi-turn 8-shaped stimulation coil, a middle layer multi-turn 8-shaped stimulation coil and an upper layer multi-turn 8-shaped stimulation coil, wherein the inner diameters of the lower layer multi-turn 8-shaped stimulation coil, the middle layer multi-turn 8-shaped stimulation coil and the upper layer multi-turn 8-shaped stimulation coil increase in turn.
[0014] In a possible design, the multi-layer 8-shaped stimulation coil is wound by a wire, and the winding direction of the coil is: first, the first side coil unit of the uppermost layer 8-shaped stimulation coil is wound from top to bottom to the first side coil unit of the lowermost layer 8-shaped stimulation coil, then the first side coil unit of the lowermost layer 8-shaped stimulation coil is wound in parallel to the second side coil unit of the lowermost layer 8-shaped stimulation coil, and finally the second side coil unit of the lowermost layer 8-shaped stimulation coil is wound from bottom to top to the second side coil unit of the uppermost layer 8-shaped stimulation coil, wherein the first side and the second side are opposite sides.
[0015] In a possible design, the multi-layer 8-shaped stimulation coil is also used for adjusting the stimulation intensity and the stimulation focusing on the bio-electromagnetic stimulation target area by different turns of each layer of the 8-shaped stimulation coil.
[0016] In a possible design, the multi-layer 8-shaped stimulation coil is also used for improving the stimulation focusing on the bio-electromagnetic stimulation target area by reducing the turn ratio of the middle layer 8-shaped stimulation coil and increasing the turn ratio of the lower layer 8-shaped stimulation coil.
[0017] In a possible design, the shape of the coil unit is circular, rectangular, pentagonal or regular polygonal.
[0018] In a second aspect, a gradient-tuned excitation system for bioelectromagnetic stimulation is provided, comprising a control module, an energy storage capacitor, a discharge switch, a discharge circuit, and a gradient-tuned excitation coil structure for bioelectromagnetic stimulation as described in the first aspect, wherein an output terminal of the control module is electrically connected to a controlled terminal of the discharge switch.
[0019] One terminal of the discharge switch is electrically connected to a positive terminal of the energy storage capacitor, another terminal of the discharge switch is electrically connected to a positive input terminal of the discharge circuit, a negative terminal of the energy storage capacitor is electrically connected to a negative input terminal of the discharge circuit, a positive output terminal of the discharge circuit is electrically connected to an excitation current introduction terminal in the gradient-tuned excitation coil structure, and a negative output terminal of the discharge circuit is electrically connected to an excitation current introduction terminal in the gradient-tuned excitation coil structure.
[0020] The control module is configured to control the discharge switch to conduct when a voltage across the energy storage capacitor reaches an expected value, so as to discharge the energy storage capacitor through the discharge circuit.
[0021] The discharge circuit is configured to send an excitation current to the gradient-tuned excitation coil structure when the energy storage capacitor is discharging.
[0022] In one possible design, the system further comprises a first resistor, a second resistor, and a clamping diode, wherein two terminals of the first resistor are respectively electrically connected to the other terminal of the discharge switch and the positive input terminal of the discharge circuit, one terminal of the second resistor is electrically connected to the other terminal of the discharge switch, another terminal of the second resistor is electrically connected to a cathode of the clamping diode, and an anode of the clamping diode is electrically connected to the negative input terminal of the discharge circuit.
[0023] In one possible design, the system further comprises an information acquisition module connected to the control module, wherein the information acquisition module is configured to acquire electrophysiological response information generated by stimulation when a target region of the bioelectromagnetic stimulation is stimulated, and transmit the electrophysiological response information to the control module for information analysis.
[0024] In one possible design, the system further comprises a charging power supply and a charging switch, wherein a controlled terminal of the charging switch is electrically connected to an output terminal of the control module.
[0025] A positive output terminal of the charging power supply is electrically connected to one terminal of the charging switch, another terminal of the charging switch is electrically connected to a positive terminal of the energy storage capacitor, and a negative output terminal of the charging power supply is electrically connected to a negative terminal of the energy storage capacitor.
[0026] The charging power supply is configured to convert alternating current into direct current.
[0027] The control module is further configured to control the charging switch to be turned on to charge the energy storage capacitor until the voltage across the energy storage capacitor reaches a predetermined value.
[0028] The above-mentioned scheme has the following advantages:
[0029] (1) The application provides a new stimulation coil design scheme which can significantly improve the focusing property of the coil while ensuring the stimulation intensity and the inductance value of the coil, i.e., a multi-layer 8-shaped stimulation coil used for being horizontally placed above a biological electromagnetic stimulation target region, the inner diameter of each layer of the 8-shaped stimulation coil is increased layer by layer from bottom to top, and the two coil units in each layer of the 8-shaped stimulation coil are left-right symmetrical, the multi-layer 8-shaped stimulation coil is used for being connected to an excitation current through a discharge circuit to play a biological electromagnetic stimulation role on the target region, so that the focusing property of the target region is significantly improved without losing much induced electric field intensity, the hidden danger caused by the too large focusing area is eliminated, a higher electric field intensity is generated at the cerebral cortex, the effectiveness of stimulating the brain is ensured, and the practical application and popularization are facilitated.
[0030] (2) The focusing property of the biological electromagnetic stimulation target region can be further improved by adjusting the turn ratio between layers, the adverse effects on non-target regions are further effectively reduced, and the safety of transcranial electromagnetic stimulation treatment is ensured. BRIEF DESCRIPTION OF DRAWINGS
[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.
[0032] Figure 1 The isometric winding diagram of the gradient tuning type excitation coil structure for biological electromagnetic stimulation provided by the embodiments of the present application.
[0033] Figure 2 The XZ plane and current flow direction analysis diagram of the gradient tuning type excitation coil structure provided by the embodiments of the present application.
[0034] Figure 3 The arrangement relationship diagram of the gradient tuning type excitation coil structure and the human head provided by the embodiments of the present application. Figure 3 (a) in the above figure shows a three-dimensional structure schematic diagram of the arrangement relationship, Figure 3 (b) in the above figure shows a top view structure schematic diagram of the arrangement relationship.
[0035] Figure 4 The schematic diagram of the intracranial target plane and the target area test line provided by the embodiment of the present application, wherein, Figure 4 (a) of the above shows the schematic diagram of the stereoscopic structure of the intracranial target plane and the target area test line, Figure 4 (b) of the above shows the schematic diagram of the side view structure of the intracranial target plane and the target area test line, Figure 4 (c) of the above shows the schematic diagram of the top view structure of the intracranial target plane and the target area test line.
[0036] Figure 5 The example diagram of the intracranial stimulation effect generated based on the different inner diameters of the coil provided by the embodiment of the present application, wherein, Figure 5 (a) of the above shows the example diagram of the linear relationship between the inner diameter of the bottom layer coil and the intracranial target area stimulation intensity generated based on the different inner diameters of the middle layer coil, Figure 5 (b) of the above shows the example diagram of the linear relationship between the inner diameter of the bottom layer coil and the intracranial target area focusing area generated based on the different inner diameters of the middle layer coil, Figure 5 (c) of the above shows the example diagram of the linear relationship between the inner diameter of the middle layer coil and the intracranial target area stimulation intensity generated based on the different inner diameters of the bottom layer coil, Figure 5 (d) of the above shows the example diagram of the linear relationship between the inner diameter of the middle layer coil and the intracranial target area focusing area generated based on the different inner diameters of the bottom layer coil.
[0037] Figure 6 The example diagram of the coil intracranial stimulation effect generated based on the different turns of each layer provided by the embodiment of the present application.
[0038] Figure 7 The example diagram of the stimulation effect of the traditional 8-shaped stimulation coil in the intracranial target area provided by the embodiment of the present application.
[0039] Figure 8 The example diagram of the stimulation effect of the gradient tuning type excitation coil structure in the intracranial target area provided by the embodiment of the present application.
[0040] Figure 9 The structural schematic diagram of the gradient tuning type excitation system for bioelectromagnetic stimulation provided by the embodiment of the present application. DETAILED DESCRIPTION
[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the present application will be briefly introduced below in connection with the drawings and the description of the embodiments or the prior art. Obviously, the following description of the drawings is only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings. It should be noted that the description of these embodiments is used to help understand the present application, but does not constitute a limitation on the present application.
[0042] It should be understood that although the terms first and second, etc. may be used herein to describe various objects, these objects should not be limited by these terms. These terms are only used to distinguish one object from another object. For example, a first object can be referred to as a second object, and similarly, a second object can be referred to as a first object, without departing from the scope of the example embodiments of the present application.
[0043] It should be understood that for the term "and / or" which may appear in the present application, it is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which means that there are three cases of A alone, B alone or A and B together; For example, A, B and / or C, means that any one of A, B and C or any combination thereof exists; for the term " / and" which may appear in the present application, it is another description of the relationship of another associated object, which means that there can be two relationships, for example, A / and B, which means that there are two cases of A alone or A and B together; in addition, for the character " / " which may appear in the present application, it generally means that the associated objects before and after are an "or" relationship.
[0044] Embodiment:
[0045] As shown in Figures 1-3 The first aspect of the present embodiment provides a gradient-tuned excitation coil structure for bioelectromagnetic stimulation, which includes but is not limited to a multi-layer 8-shaped stimulation coil 1 for being horizontally placed above a bioelectromagnetic stimulation target area 100; the inner diameter of each layer of the 8-shaped stimulation coil 1 increases layer by layer from bottom to top, and the two coil units in each layer of the 8-shaped stimulation coil are left-right symmetrical; the multi-layer 8-shaped stimulation coil 1 is used to pass through a discharge circuit to input an excitation current to play a bioelectromagnetic stimulation role on the bioelectromagnetic stimulation target area 100.
[0046] As shown in Figures 1-3As shown in the specific structure of the gradient tuning excitation coil structure, the multi-layer 8-shaped stimulation coil 1 adopts a three-layer symmetrical configuration and has six coil units, i.e., it includes a lower multi-turn 8-shaped stimulation coil 11, a middle multi-turn 8-shaped stimulation coil 12, and an upper multi-turn 8-shaped stimulation coil 13. The inner diameters of the lower multi-turn 8-shaped stimulation coil 11, the middle multi-turn 8-shaped stimulation coil 12, and the upper multi-turn 8-shaped stimulation coil 13 increase in turn. Two coil units in the lower multi-turn 8-shaped stimulation coil 11 are left-right symmetrical, two coil units in the middle multi-turn 8-shaped stimulation coil 12 are also left-right symmetrical, and two coil units in the upper multi-turn 8-shaped stimulation coil 13 are also left-right symmetrical, i.e., all the left-right coils present a symmetrical spatial structure in the overall spatial structure. The number of turns of the lower multi-turn 8-shaped stimulation coil 11, the middle multi-turn 8-shaped stimulation coil 12, and the upper multi-turn 8-shaped stimulation coil 13 is four.
[0047] As shown in Figure 1 The multi-layer 8-shaped stimulation coil 1 is wound by one wire, and the winding direction is: first, from the first side coil unit of the uppermost 8-shaped stimulation coil to the first side coil unit of the lowermost 8-shaped stimulation coil from top to bottom, then from the first side coil unit of the lowermost 8-shaped stimulation coil to the second side coil unit of the lowermost 8-shaped stimulation coil in parallel, and finally from the second side coil unit of the lowermost 8-shaped stimulation coil to the second side coil unit of the uppermost 8-shaped stimulation coil from bottom to top, wherein the first side and the second side are the left and right sides. Such layered winding can form three independent loops and increase the inner diameter of the coil along the Z-axis direction (i.e., from bottom to top) layer by layer, realizing the following working principle: according to the superposition principle of magnetic field, the same side current flow direction of the left and right coil structure can form a stronger stimulation intensity in the lower area of the coil, and by adjusting the inner diameter of the bottom coil, the focusing of the induced electric field can be improved in a certain range; at the same time, although reducing the inner diameter of the coil will reduce the impact on non-target tissues, the effective energy of part of the induced electric field of the coil is sacrificed, so the inner diameter of the middle and upper coils can be set to increase layer by layer compared with the bottom coil, which compensates for the loss of energy of the positive peak of the induced electric field to some extent, improves the stimulation intensity and stimulation focusing, i.e., the multi-layer 8-shaped stimulation coil 1 can be used to adjust the stimulation intensity and stimulation focusing of the biological electromagnetic stimulation target area 100 by the different inner diameters of the layers of 8-shaped stimulation coils.
[0048] As shown in Figure 2As shown, the lower layer multi-turn figure-8 shaped stimulating coil 11, the middle layer multi-turn figure-8 shaped stimulating coil 12 and the upper layer multi-turn figure-8 shaped stimulating coil 13 are all mirror-symmetrically distributed along the YZ plane, and each layer of coil can be wound into a circular, rectangular, pentagonal or regular polygonal geometry based on an independent skeleton (i.e. the shape of the coil unit can be but is not limited to circular, rectangular, pentagonal or regular polygonal, etc.), and the coil plane is strictly parallel to the XY reference plane, and the overall structure presents left-right symmetry characteristics in the working area (i.e. the YZ plane). For clear analysis of current distribution characteristics, the coil model is cut along the XZ plane, and the cross-section presents symmetrically distributed left and right parts. Figure 2 The thickness of the coil unit along the Z-axis direction is represented by tk (unit: mm), Figure 2 The inner diameter of the upper layer multi-turn figure-8 shaped stimulating coil 13 parallel to the X-axis is represented by R2 (unit: mm), the inner diameter of the middle layer multi-turn figure-8 shaped stimulating coil 12 is represented by R1 (unit: mm), and the inner diameter of the lower layer multi-turn figure-8 shaped stimulating coil 11 is represented by r (unit: mm). The geometric structure of the multi-layer figure-8 shaped stimulating coil 1 can be determined by the foregoing parameters. In addition, taking the left coil as an example, the upper, middle and lower three layers of the multi-layer figure-8 shaped stimulating coil 1 all have the same counterclockwise current flow direction, and the right three layers of the coil have the same clockwise current flow direction. The current flow direction of the two sides of the coil remains the same.
[0049] As shown in Figure 3 The gradient-tuned excitation coil structure and the human head are parallel to the XY plane: when the lower layer multi-turn figure-8 shaped stimulating coil 11, the middle layer multi-turn figure-8 shaped stimulating coil 12 and the upper layer multi-turn figure-8 shaped stimulating coil 13 in the gradient-tuned excitation coil structure are placed above the human head, the relative position three-dimensional diagram and the XY plane diagram of the gradient-tuned excitation coil structure and the human head are shown in (a) of Figure 3 When in the XY plane, the lower layer multi-turn figure-8 shaped stimulating coil 11, the middle layer multi-turn figure-8 shaped stimulating coil 12 and the upper layer multi-turn figure-8 shaped stimulating coil 13 are placed in overlap, with a 1mm spacing between each layer, the relative position three-dimensional diagram and the XY plane diagram of the gradient-tuned excitation coil structure and the human head are shown in (b) of Figure 3 .
[0050] As shown in Figure 4As shown, the scalp vertex is taken as the origin, and to meet the stimulation depth requirement, the XY plane 20 mm below the scalp is taken as the bioelectromagnetic stimulation target region 100, and the distribution characteristics of the target region induction plane induction electric field space are extracted along the X test line 201 (i.e., y = 0, z = -20 mm), the Y test line 202 (i.e., x = 0, z = -20 mm), and the Z test line 203 (i.e., x = 0, y = 0). The induction electric field value generated by the stimulation coil in the brain is called the stimulation intensity, which is represented by the maximum value Eymax of the Y component of the target region induction electric field; the stimulation depth represents the penetration ability of the induction electric field in the brain, and the intracranial induction electric field decays along the Z test line 203 from the scalp vertex. When the induction electric field intensity decays to one half of Eymax, the stimulation depth can be extracted from the Z test line 203; the focusing property S 1 / 2 represents the ability of the induction electric field to concentrate in a certain area, which is generally represented by the ratio of the volume greater than one half of the maximum induction electric field value (Eymax) to the depth. The smaller the ratio, the better the focusing property. To evaluate the stimulation effect, the above aspects are generally compared, and reasonable selection of the performance indicators can improve the stimulation effect to a greater extent and exert advantages.
[0051] Based on the intracranial stimulation effect generated by different coil inner diameters, as shown in Figure 5 , under the condition that other parameters are constant, the change in the inner diameter of each layer can effectively affect the stimulation performance and focusing property. The pulse current amplitude is 3500 A, the coil thickness tk = 4 mm, the upper layer inner diameter of the auxiliary coil R2 = 28 mm, and the number of turns N = 4 turns of each layer remain unchanged. The middle layer inner diameter and the bottom layer inner diameter are set to 16 mm, 20 mm, and 24 mm, respectively, for comparison of the stimulation effects of the three groups. As shown in Figure 5 (a) and (c) in , with the increase of the bottom layer inner diameter and the middle layer inner diameter, the stimulation intensity shows an upward trend, and when the middle layer inner diameter is R1 = 32 mm and the bottom layer inner diameter is r = 24 mm, the maximum induction electric field intensity can reach more than 160 V / m. As shown in Figure 5 (b) and (d) in , with the increase of the bottom layer inner diameter and the middle layer inner diameter, the focusing area gradually increases, and the smaller the focusing area, the better the focusing property. When the middle layer inner diameter is R1 = 16 mm and the bottom layer inner diameter is r = 16 mm, the focusing area is maintained at 26.55 cm 2 , which is 16.93% higher than that of the traditional 8-shaped coil, which shows that changing the inner diameters of the middle layer coil and the bottom layer coil can effectively tune the stimulation intensity and focusing area of the magnetic field in the target region in the brain.
[0052] Based on the intracranial stimulation effect generated by different numbers of turns of each layer, as shown in Figure 6As shown in the figure, the pulse current amplitude of the coil is 3500A, the coil thickness is tk = 4mm, the inner diameter of the upper layer of the auxiliary coil is R2 = 28mm, the inner diameter of the middle layer of the auxiliary coil is R1 = 23mm, and the inner diameter of the bottom layer is r = 16mm. Under the parameter conditions, the number of turns of the upper layer is fixed to N = 2, the total number of turns remains unchanged, the number of turns of the middle layer coil is reduced to 8, 6, 4 and 2 turns in sequence, and the number of turns of the bottom layer coil is increased by 2, 4, 6 and 8 turns in sequence; as shown in the figure Figure 6 As shown in the figure, the stimulation intensity showed a significant decreasing trend, from 144.94V / m to 99.75V / m, a decrease of 31.17%. The number of turns in the middle layer was significantly positively correlated with the stimulation intensity. A decrease in the number of turns in the middle layer would lead to a decrease in the stimulation intensity. 2 Reduced to 26.63cm 2 Compared with the traditional figure-8 stimulation coil, the focusing improvement rate increases from 4.76% to 16.68%. It can be seen that reducing the number of turns of the middle coil and increasing the number of turns of the lower coil are helpful to improve the focusing. While maintaining the total number of turns constant, by reducing the proportion of the middle winding and correspondingly increasing the bottom winding configuration, the coordinated optimization of the stimulation intensity and focusing characteristics can be achieved, that is, the multi-layer figure-8 stimulation coil 1 is also used to adjust the stimulation intensity and stimulation focusing of the bio-electromagnetic stimulation target area 100 through the different numbers of turns of each layer of figure-8 stimulation coil, and specifically, the multi-layer figure-8 stimulation coil 1 is also used to improve the stimulation focusing of the bio-electromagnetic stimulation target area 100 by reducing the proportion of the number of turns of the middle layer figure-8 stimulation coil and increasing the proportion of the number of turns of the lower layer figure-8 stimulation coil.
[0053] The induced electric field intensity distribution generated by the traditional figure-8 coil in the intracranial target plane is as follows Figure 7 As shown in Figure 2, when the stimulation pulse current is set to 3500A, the coil inner diameter is 28mm, and the total number of turns is N=12, the three-dimensional distribution and equivalent distribution of the induced electric field generated by the traditional figure-8 coil at the target plane at a stimulation depth of 20mm are shown in Figure 2. Figure 7 As shown: the generated electric field strength is Emax = 168.48 V / m, and the stimulation focal area is 31.96 cm 2 The stimulation depth is 3.23 cm. The induced electric field intensity distribution generated by the gradient-tuned excitation coil structure in the intracranial target plane is as follows: Figure 8 As shown in the figure, the amplitude of the stimulation pulse current is 3500A, and the inner diameters of the coils from top to bottom are arranged in a decreasing integer ratio of 28:23:16, which makes the stimulation intensity and focusing performance more balanced. The three-dimensional distribution and equivalent distribution of the induced electric field generated by the gradient-tuned excitation coil structure at the target plane at a stimulation depth of 20mm are shown in the figure. Figure 8 As shown: The stimulation intensity of this coil structure reaches Emax = 120.26V / m, and the stimulation focal area is 27.09cm 2, the stimulation depth is 3.21cm, and the focusing effect can be improved by 15.24% compared with the traditional 8-shaped coil. Therefore, the inductive electric field distribution generated by the coil structure provided in the embodiment is more ideal, and the stimulation area can be effectively reduced and the focusing effect can be improved.
[0054] As shown in Figure 9 The second aspect of the embodiment provides a gradient tuning excitation system applying the gradient tuning excitation coil structure of the first aspect, which includes but is not limited to a control module AD, an energy storage capacitor C, a discharge switch K1, a discharge circuit FD and the gradient tuning excitation coil structure for bioelectromagnetic stimulation as described in the first aspect. The output end of the control module AD is electrically connected to the controlled end of the discharge switch K1. One end of the positive electrode of the energy storage capacitor C is electrically connected to one end of the discharge switch K1. The other end of the discharge switch K1 is electrically connected to the positive input end of the discharge circuit FD. The negative electrode of the energy storage capacitor C is electrically connected to the negative input end of the discharge circuit FD. The positive output end of the discharge circuit FD is electrically connected to the excitation current introduction end of the gradient tuning excitation coil structure. The negative output end of the discharge circuit FD is electrically connected to the excitation current introduction end of the gradient tuning excitation coil structure. The control module AD is used to control the discharge switch K1 to be turned on when the voltage across the energy storage capacitor C reaches the expected value, so as to discharge the energy storage capacitor C through the discharge circuit FD. The discharge circuit FD is used to send excitation current to the gradient tuning excitation coil structure when the energy storage capacitor C is discharged.
[0055] As shown in Figure 9 In the specific structure of the gradient tuning excitation system, the control module AD is used as the system control center, which can be realized by a microcontroller with the model of STM32F105 series. In addition, the energy storage capacitor C, the discharge switch K1 and the discharge circuit FD and the like can be realized by existing devices or corresponding circuits. When the voltage across the energy storage capacitor C reaches the stimulation range, the discharge switch K1 is opened to generate a time-varying pulse current in the coil. The time-varying current generates a time-varying magnetic field, which generates an induced electric field in the intracranial target area. Then, the electro-physiological response in the intracranial is received by the information acquisition module SC.
[0056] Preferably, the first resistor R1, the second resistor R2 and the clamping diode D are further included. The two ends of the first resistor R1 are respectively and one-to-one electrically connected to the other end of the discharge switch K1 and the positive input end of the discharge circuit FD. One end of the second resistor R2 is electrically connected to the other end of the discharge switch K1. The other end of the second resistor R2 is electrically connected to the cathode of the clamping diode D. The anode of the clamping diode D is electrically connected to the negative input end of the discharge circuit FD, as shown in Figure 9As shown, the current limiting purpose can be achieved by resistance design, and the preparation work for subsequent stimulation can be done by the clamping of the diode.
[0057] Preferably, the system further comprises an information acquisition module SC connected to the control module AD, wherein the information acquisition module SC is configured to acquire the electrophysiological response information generated by the stimulation when the target area 100 is stimulated, and transmit the electrophysiological response information to the control module AD for information analysis.
[0058] Preferably, the system further comprises a charging power supply CD and a charging switch K2, wherein the controlled end of the charging switch K2 is electrically connected to the output end of the control module AD; one end of the charging switch K2 is electrically connected to the positive output end of the charging power supply CD, the other end of the charging switch K2 is electrically connected to the positive pole of the energy storage capacitor C, and the negative output end of the charging power supply CD is electrically connected to the negative pole of the energy storage capacitor C; the charging power supply CD is configured to convert alternating current into direct current; and the control module AD is further configured to control the charging switch K2 to be turned on to charge the energy storage capacitor C until the voltage across the energy storage capacitor C reaches an expected value, such as 3.3V. Figure 9 As shown, the charging power supply CD charges the energy storage capacitor C through the charging switch K2, so as to prepare for the accurate work of subsequent stimulation, and the control module AD can control the discharging switch K1 and the charging switch K2 to achieve the purpose of repeated stimulation. In addition, the discharging switch K1 or the charging switch K2 preferably adopts a thyristor, so as to utilize the advantage of small loss, which is beneficial to energy saving.
[0059] The working process, working details and technical effects of the foregoing system provided by the second aspect of the embodiment can be referred to the gradient tuning type excitation coil structure described in the first aspect, and will not be repeated here.
[0060] Finally, it should be noted that: the above only describes the preferred embodiments of the present application, and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.
Claims
1. A gradient-tuned excitation coil structure for bioelectromagnetic stimulation, characterized in that: It comprises a multi-layer 8-shaped stimulation coil (1) for horizontal placement above a bioelectromagnetic stimulation target area (100); The inner diameter of each layer of the figure-8 stimulation coil in the multi-layer figure-8 stimulation coil (1) increases layer by layer from bottom to top, and the two coil units in each layer of the figure-8 stimulation coil are bilaterally symmetrical; The multi-layer figure-8 shaped stimulation coil (1) is used to connect an excitation current through a discharge circuit to exert a bioelectromagnetic stimulation effect on the bioelectromagnetic stimulation target area (100).
2. The gradient-tuned excitation coil structure according to claim 1, wherein: The multi-layer figure-8 stimulation coil (1) comprises a lower-layer multi-turn figure-8 stimulation coil (11), a middle-layer multi-turn figure-8 stimulation coil (12) and an upper-layer multi-turn figure-8 stimulation coil (13), wherein the inner diameters of the lower-layer multi-turn figure-8 stimulation coil (11), the middle-layer multi-turn figure-8 stimulation coil (12) and the upper-layer multi-turn figure-8 stimulation coil (13) increase in sequence.
3. The gradient-tuned excitation coil structure according to claim 1, wherein: The multi-layer figure-8 stimulation coil (1) is wound by a single conductor, and the coil winding direction is: firstly, the first side coil unit of the top figure-8 stimulation coil is wound from top to bottom to the first side coil unit of the bottom figure-8 stimulation coil, then the first side coil unit of the bottom figure-8 stimulation coil is wound in parallel to the second side coil unit of the bottom figure-8 stimulation coil, and finally, the second side coil unit of the bottom figure-8 stimulation coil is wound from bottom to top to the second side coil unit of the top figure-8 stimulation coil, wherein the first side and the second side are two opposite sides.
4. The gradient-tuned excitation coil structure according to claim 1, wherein: The multi-layer figure-8 shaped stimulation coil (1) is also used to adjust the stimulation intensity and stimulation focus of the bioelectromagnetic stimulation target area (100) through the different numbers of turns of the figure-8 shaped stimulation coils in each layer.
5. The gradient-tuned excitation coil structure according to claim 1, wherein: The multi-layer figure-8 stimulation coil (1) is also used to improve the stimulation focus of the bioelectromagnetic stimulation target area (100) by reducing the proportion of turns of the middle-layer figure-8 stimulation coil and increasing the proportion of turns of the lower-layer figure-8 stimulation coil.
6. The gradient-tuned excitation coil structure according to claim 1, wherein: The coil unit is in a shape of a circle, a rectangle, a pentagon or a regular polygon.
7. A gradient-tuned excitation system for bioelectromagnetic stimulation, characterized in that: The invention comprises a control module (AD), an energy storage capacitor (C), a discharge switch (K1), a discharge circuit (FD), and a gradient-tuned excitation coil structure for bioelectromagnetic stimulation according to any one of claims 1 to 6, wherein the output end of the control module (AD) is electrically connected to the controlled end of the discharge switch (K1); The positive electrode of the energy storage capacitor (C) is electrically connected to one end of the discharge switch (K1), the other end of the discharge switch (K1) is electrically connected to the positive input end of the discharge circuit (FD), the negative electrode of the energy storage capacitor (C) is electrically connected to the negative input end of the discharge circuit (FD), the positive output end of the discharge circuit (FD) is electrically connected to the excitation current introduction end of the gradient tuning excitation coil structure, and the negative output end of the discharge circuit (FD) is electrically connected to the excitation current lead-out end of the gradient tuning excitation coil structure; The control module (AD) is used to control the discharge switch (K1) to be turned on when the voltage across the energy storage capacitor (C) reaches a desired value, so as to discharge the energy storage capacitor (C) through the discharge circuit (FD); The discharge circuit (FD) is used to send an excitation current to the gradient-tuned excitation coil structure when the energy storage capacitor (C) is discharged.
8. The gradient-tuned excitation system according to claim 7, wherein: The invention also includes a first resistor (R1), a second resistor (R2) and a clamping diode (D), wherein two ends of the first resistor (R1) are electrically connected to the other end of the discharge switch (K1) and the positive input end of the discharge circuit (FD) respectively, one end of the second resistor (R2) is electrically connected to the other end of the discharge switch (K1), the other end of the second resistor (R2) is electrically connected to the cathode of the clamping diode (D), and the anode of the clamping diode (D) is electrically connected to the negative input end of the discharge circuit (FD).
9. The gradient-tuned excitation system according to claim 7, wherein: The invention also includes an information acquisition module (SC) communicatively connected to the control module (AD), wherein the information acquisition module (SC) is used to acquire electrophysiological response information generated by the stimulation when the bioelectromagnetic stimulation target area (100) is stimulated, and transmit the electrophysiological response information to the control module (AD) for information analysis.
10. The gradient-tuned excitation system according to claim 7, wherein: It also includes a charging power supply (CD) and a charging switch (K2), wherein the controlled end of the charging switch (K2) is electrically connected to the output end of the control module (AD); The positive output end of the charging power supply (CD) is electrically connected to one end of the charging switch (K2), the other end of the charging switch (K2) is electrically connected to the positive electrode of the energy storage capacitor (C), and the negative output end of the charging power supply (CD) is electrically connected to the negative electrode of the energy storage capacitor (C); The charging power supply (CD) is used to convert alternating current into direct current; The control module (AD) is further configured to control the charging switch (K2) to be turned on so as to charge the energy storage capacitor (C) until the voltage across both ends of the energy storage capacitor (C) reaches a desired value.