Folding transcranial magnetic stimulation coil

Abstract

The utility model provides a folding transcranial magnetic stimulation coil, which comprises a left coil and a right coil, the left coil and the right coil are symmetrically arranged, the left coil and the right coil are respectively folded along a transverse axis and a longitudinal axis, and the folding angle is variable. The folding angles of the two coils along the transverse axis and the longitudinal axis are adjusted, the fitting degree of the coils and the human brain is improved, the stimulation intensity and the stimulation depth of the transcranial magnetic stimulation coil on the cerebral cortex layer are improved on the basis that focusing performance is kept, and the transcranial magnetic stimulation coil is simple in structure, convenient to machine and capable of being widely applied to the technical field of medical equipment.

Description

Technical Field

[0001] The utility model belongs to the technical field of transcranial magnetic stimulation, and in particular relates to a folded transcranial magnetic stimulation coil. Background Art

[0002] As a non-invasive and non-intrusive neuromodulation technology, Transcranial Magnetic Simulation (TMS) is based on electromagnetic field theory and plays an indispensable role in the treatment of brain neurological diseases and mental illnesses. Based on the Biot-Savart law and Faraday's law of electromagnetic induction, TMS uses pulsed current in an energized coil to generate a pulsed magnetic field around the coil, which further generates an induced electric field in the head, thereby stimulating the target nerves and surrounding tissues. Therefore, it has great development potential in research fields such as biomedicine and rehabilitation medicine.

[0003] The figure-8 coil is a widely used TMS coil. The figure-8 coil consists of two circular coils arranged closely on the same plane. The two coils apply excitation currents in opposite directions. The induced electric fields are superimposed on each other just below the intersection of the coils. The electric field strength is much greater than the surrounding electric field strength, and it has good focusing properties. It has now been commercialized. However, the traditional figure-8 coil still has the problem of insufficient stimulation intensity and stimulation depth, and it is difficult to balance the stimulation accuracy and stimulation depth. For example, although the traditional figure-8 coil can obtain a relatively small focusing range, the stimulation intensity and stimulation depth are often insufficient, and it is impossible to achieve stimulation of deep parts of the brain; in addition, the traditional figure-8 coil is a planar coil, and its fit with the human brain needs to be improved. Although researchers have designed various coils that can fit the shape of the human brain, the structural design process of these coils is complicated and cannot be flexibly changed, so they can only be applied to a single treatment scenario.

[0004] Wang Yong et al. disclosed in the Chinese invention patent CN117205444A the "transcranial magnetic folding coil and its evaluation method and computer device", which includes a centrally symmetrical transcranial magnetic coil, wherein the transcranial magnetic coil is provided with a first coil and a second coil, wherein the first coil is folded upward along the folding chord of the first coil, and the second coil is folded upward along the folding chord of the second coil, the folding chord of the first coil and the folding chord of the second coil are parallel and equal, and the folding angles of the first coil and the second coil are equal; the center line of the line connecting the first coil and the second coil is perpendicular to the folding chord of the first coil and the folding chord of the second coil respectively, and the folding distance of the first coil and the folding distance of the second coil are equal, and the folding distance is the distance from the central symmetry point to the folding chord. The coil can improve the focusing degree, but the coil is folded along the short axis, and folded upward, and the folded part is far away from the human brain, which can only improve the focusing degree, and cannot take into account the stimulation depth. Summary of the invention

[0005] In order to solve at least one of the problems existing in the prior art to a certain extent, the utility model provides a foldable transcranial magnetic stimulation coil, which improves the fit between the transcranial magnetic stimulation coil and the human brain by adjusting the folding angles of the two coils along the horizontal axis and the vertical axis. On the basis of maintaining a certain focus, the stimulation intensity and stimulation depth of the transcranial magnetic stimulation coil in the cerebral cortex layer are improved. The utility model has a simple structure and is easy to process, and can be widely used in the field of medical equipment technology.

[0006] In order to achieve the aforementioned objectives, the utility model provides a folded transcranial magnetic stimulation coil, comprising a left coil and a right coil, wherein currents in opposite directions are respectively passed through the left coil and the right coil to generate a focusing electric field, wherein both the left coil and the right coil can be folded along the horizontal axis and the vertical axis, the folding angle is variable, and the positions of the left coil and the right coil are symmetrical to each other.

[0007] After adopting the above scheme, the utility model can improve the fit between the coil and the human brain by adjusting the folding angles of the left coil and the right coil along the horizontal axis and the vertical axis, so that the energy utilization rate of the magnetic field is effectively improved. On the basis of maintaining a certain stimulation accuracy, the stimulation intensity and stimulation depth of the transcranial magnetic stimulation coil in the cerebral cortex layer are improved.

[0008] Furthermore, the left coil and the right coil are both copper coils.

[0009] Furthermore, a distance is left between the left coil and the right coil.

[0010] Furthermore, the original shapes of the left coil and the right coil before folding are circular.

[0011] Further, the left coil and the right coil are both multi-turn structures. Preferably, the number of turns of the left coil and the right coil are both 5. Further preferably, the radius of the left coil from inside to outside is: 30mm, 32.5mm, 35mm, 37.5mm, 40mm, and the radius of the right coil from inside to outside is: 30mm, 32.5mm, 35mm, 37.5mm, 40mm.

[0012] Furthermore, the wire cross-section parameters of the left coil and the right coil are the same. Preferably, the wire cross-section parameters of the left coil and the right coil are both 1 mm×1 mm.

[0013] Furthermore, the folded transcranial magnetic stimulation coil can be reduced or enlarged in proportion.

[0014] Furthermore, the center line of the left coil and the right coil is taken as the x-axis, the point between the centers of the left coil and the right coil is taken as the y-axis and the y-axis coincides with the axis of symmetry of the left coil and the right coil, the z-axis is perpendicular to the plane where the left coil and the right coil are located, the side where the left coil and the right coil are close to each other is taken as the inner wing, and the other opposite side is taken as the outer wing, and the left coil and the right coil are separated into a front wing and a rear wing with the xz plane as the dividing interface, the front wing and the rear wing of the left coil and the right coil are folded downward with the x-axis as the rotation axis, the inner wings of the left coil and the right coil remain stationary, and the outer wings are folded downward with the axes parallel to the y-axis and passing through the centers of the corresponding coils as the rotation axes.

[0015] Furthermore, the folding angle α of the front wing and the rear wing folded downward with the x-axis as the rotation axis ranges from 0° to 15°.

[0016] Furthermore, the inner wing remains stationary, and the folding angle β of the outer wing folded downward ranges from 0° to 45°.

[0017] Compared with the prior art, the present invention can achieve at least the following beneficial effects:

[0018] (1) The utility model can adapt to various sizes and shapes of human brains by flexibly adjusting the folding angles of the left coil and the right coil along the horizontal axis and the vertical axis, thereby improving the fit between the coil and the human brain and being able to adapt to a variety of application scenarios.

[0019] (2) At present, most transcranial magnetic stimulation coils have contradictory performances in terms of focusing and stimulation depth. However, based on the figure-eight coil, the present invention folds the coil downward along the horizontal and vertical axes to deform it. The deformed folded coil is curved as a whole, which can better fit the human brain. On the basis of maintaining a certain focusing performance, the induced electric field intensity and stimulation depth of the coil stimulation can be improved, thus achieving deeper brain stimulation.

[0020] (3) The present invention is designed based on the structure of an 8-shaped coil. Compared with finding a complex coil structure to improve stimulation performance, the present invention is simple and easy to understand and has low manufacturing complexity. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work, among which:

[0022] Figure 1 It is a schematic diagram of a multi-turn structure of a folded transcranial magnetic stimulation coil provided in an embodiment of the utility model.

[0023] Figure 2 This is a front view of a folded transcranial magnetic stimulation coil provided by an embodiment of the utility model.

[0024] Figure 3 It is a left view of a folded transcranial magnetic stimulation coil provided by an embodiment of the utility model.

[0025] Figure 4 It is a top view of a folded transcranial magnetic stimulation coil provided by an embodiment of the utility model.

[0026] Figure 5 It is a schematic diagram of the unit structure of a folded transcranial magnetic stimulation coil provided in an embodiment of the utility model.

[0027] Figure 6 It is a diagram describing the position of each wing of the unit coil provided in an embodiment of the utility model.

[0028] Figure 7 It is a schematic diagram of the rotation axis of a folded transcranial magnetic stimulation coil provided in an embodiment of the utility model.

[0029] Figure 8 The front and rear wings of the single-turn coil provided in the embodiment of the utility model are Figure 7 Schematic diagram of the rotation angle of axis 1 in .

[0030] Fig. 9 The outer wing edge of the single-turn coil provided in the embodiment of the utility model Figure 7 Schematic diagram of the rotation angle of axis 2 or axis 3 in.

[0031] Fig.10 It is an xz cross-section view that includes the coil and ball models and passes through the z-axis.

[0032] Fig.11 It is a schematic diagram of the electric field simulation results of the folded figure-8-shaped transcranial magnetic stimulation coil provided in an embodiment of the utility model.

[0033] Fig.12 It is a schematic diagram comparing the focusing performance of a folded figure-8-shaped transcranial magnetic stimulation coil and a standard figure-8-shaped transcranial magnetic stimulation coil provided by an embodiment of the utility model.

[0034] Fig.13 It is a schematic diagram comparing the performance of the folded figure-8-shaped transcranial magnetic stimulation coil provided by an embodiment of the utility model and other coils.

[0035] Fig.14a 2 is a graph showing the relationship between the folding angle and the electric field strength in an embodiment of the present utility model.

[0036] Fig.14b 2 is a graph showing the relationship between the folding angle and the stimulation depth in the embodiment of the utility model.

[0037] In the figure, 1. left coil, 2. right coil, 3. skull-intracranial tissue ball model. DETAILED DESCRIPTION

[0038] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0039] In the description of the utility model, if there is a description of first and second, it is only for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0040] like Figure 1-Figure 9As shown, the utility model provides a folded transcranial magnetic stimulation coil, including a left coil 1 and a right coil 2, the positions of the left coil 1 and the right coil 2 are symmetrical to each other and are arranged in an approximately 8-shaped shape, and a distance is left between the left coil 1 and the right coil 2. An xyz rectangular coordinate system is established on the coil, wherein the x-axis passes through the center of the left coil 1 and the right coil 2, the y-axis passes through the midpoint between the center of the left coil 1 and the right coil 2 and coincides with the symmetry axis between the two coils, and the z-axis is perpendicular to the plane where the left coil 1 and the right coil 2 are located, so the left coil 1 and the right coil 2 are symmetrical to each other about the yz cross section and do not contact each other, and currents in opposite directions are respectively passed into the left coil 1 and the right coil 2 to generate a focusing electric field.

[0041] The center line of the left coil and the right coil is taken as the x-axis, the point between the centers of the left coil and the right coil is taken as the y-axis, and the y-axis coincides with the symmetry axis of the left coil and the right coil, the z-axis is perpendicular to the plane where the left coil and the right coil are located, the side where the left coil and the right coil are close to each other is the inner wing, and the other opposite side is the outer wing, and the left coil and the right coil are separated into a front wing and a rear wing with the xz plane as the dividing interface, the front wing and the rear wing of the left coil and the right coil are folded downward with the x-axis as the rotation axis, the inner wings of the left coil and the right coil remain stationary, and the outer wings are folded downward with the axes parallel to the y-axis and passing through the centers of the corresponding coils as the rotation axes.

[0042] in, Figure 5 and Figure 6 The unit structure of the utility model is shown in FIG. Figure 6 , the bc-cd segment and the fg-gh segment are the front wings of the left coil 1 and the right coil 2 respectively, the ba-ad segment and the fe-eh segment are the rear wings of the left coil 1 and the right coil 2 respectively, the ad-dc segment and the eh-hg segment are the inner wings of the left coil 1 and the right coil 2 respectively, and the ab-bc segment and the ef-fg segment are the outer wings of the left coil 1 and the right coil 2 respectively. Figure 7 Axis 1 in coincides with the x-axis, Figure 7 The axis 2 and axis 3 in the figure are parallel to the y-axis and pass through the center of the left coil 1 and the right coil 2 respectively. Figure 8 and Fig. 9 As shown, the front and rear wings of the left coil 1 and the right coil 2 are folded downward with axis 1 as the rotation axis, and the folding angle is α, and the value range of α is 0-15°. In some embodiments of the present utility model, α=15°. Further, the inner wings of the left coil 1 and the right coil 2 remain stationary, and the outer wings are folded downward with axis 2 and axis 3 as the rotation axis, respectively, and the folding angle is β, and the value range of β is 0-45°. In some embodiments of the present utility model, β=45°. Among them, when α=β=0°, the coil is a standard planar figure 8 coil.

[0043] In some embodiments of the present invention, the left coil 1 and the right coil 2 are both made of copper.

[0044] In some embodiments of the present invention, the original shapes of the left coil 1 and the right coil 2 before folding are both circular.

[0045] In some embodiments of the present invention, the number of turns of the left coil 1 and the right coil 2 are both 5. The radius of the left coil 1 from inside to outside is: 30mm, 32.5mm, 35mm, 37.5mm, 40mm. The radius of the right coil 2 from inside to outside is: 30mm, 32.5mm, 35mm, 37.5mm, 40mm. It can be understood that in other embodiments, the number of turns of the coil and the radius of the coil can be changed as needed.

[0046] In some embodiments of the present invention, the wire cross-section parameters of the left coil 1 and the right coil 2 are both 1 mm×1 mm. It is understandable that in other embodiments, the wire cross-section parameters of the coils may take other values.

[0047] In some embodiments of the present invention, the folded figure-8-shaped transcranial magnetic stimulation coil can be reduced or enlarged in proportion.

[0048] In some embodiments of the present invention, the current excitation magnitude is set to 5kA and the frequency is 5kHz. Fig.10 As shown, a skull-intracranial tissue spherical model 3 is used to simulate brain tissue, wherein the spherical radius representing the intracranial tissue is 95 mm, the electrical conductivity is 4 S / m, the relative dielectric constant is 80, and the relative magnetic permeability is 1; there is a 5 mm thick shell on the surface of the sphere representing the skull, with a conductivity of 0.01 S / m, a relative dielectric constant of 13.5, and a relative magnetic permeability of 0.99. A folded 8-shaped transcranial magnetic stimulation coil folded in the direction close to the skull-intracranial tissue spherical model is placed 5 mm above the spherical model. The stimulation effect of the transcranial magnetic coil is evaluated by analyzing the induced electric field strength of the intracranial tissue, wherein the Fig.10 The distribution of electric field strength in the 180° arc (measurement line) close to one side of the coil is used to evaluate the stimulation accuracy, i.e., the focusing, of TMS. Since the minimum stimulation threshold of the electric field strength in the cortical layer in TMS is 100 V / m, this embodiment defines the maximum distance from the maximum electric field on the surface of the intracranial tissue to 100 V / m as the stimulation depth d. The greater the stimulation depth, the better the stimulation performance. Fig.11 The simulation results of the induced electric field of the folded figure-8 transcranial magnetic stimulation coil on the surface of intracranial tissue are given, and it can be seen that the coil can achieve the effect of focused stimulation.

[0049] Further comparison of the folded figure-8 transcranial magnetic stimulation coil and the standard figure-8 transcranial magnetic stimulation coil in Fig.10 The distribution of electric field strength on the measuring line, such as Fig.12 As shown. By comparing the two curves, it can be seen that the area between the angle θ of 0 and 25 degrees is the focus area of ​​the folded figure-8 coil and the standard figure-8 coil, but the induced electric field of the folded figure-8 coil is higher than that of the standard figure-8 coil, and the attenuation curve is steeper. This shows that compared with the standard figure-8 coil, the folded figure-8 coil provided by the utility model has better focusing and higher stimulation intensity.

[0050] Fig.13 The performance comparison between the folded figure-8 coil and other coils is shown. It can be seen that under the same excitation parameters, the maximum electric field strength generated by the folded figure-8 coil provided by the utility model on the surface of intracranial tissue is 345.511 V / m, which is 44.54% and 144.17% higher than those of the standard figure-8 coil and the circular coil, respectively; the stimulation depth d of the folded figure-8 coil is 25.474 mm, which is 35.41% and 115.64% higher than those of the standard figure-8 coil and the circular coil, respectively.

[0051] See also Fig.14a , Fig.14b , when the folding angle α is 0°-15° and the folding angle β is 0°-45°, increasing the folding angle can effectively improve the electric field strength and stimulation depth (a small amount of data fluctuates due to the influence of the simulation software itself). Whether the coil is folded horizontally (folding angle α) or longitudinally (folding angle β), the stimulation intensity and stimulation depth are improved accordingly, and folding in two directions at the same time has a more superimposed effect on the performance optimization. When α=15° and β=45°, the maximum electric field strength and the maximum stimulation depth can be obtained. Moreover, the coil folding angle can be adjusted within the aforementioned folding angle range to adapt to heads of different shapes and sizes.

[0052] Through the above analysis and comparison, the folded transcranial magnetic stimulation coil provided by the utility model can effectively improve the electric field strength and stimulation depth while maintaining good focusing, can achieve stimulation of deeper brain tissues, and the overall performance has been further optimized. In the embodiment of the utility model, the excitation parameters (current, frequency) and coil parameters (such as the number of turns, the radius of each coil turn, the folding angle α, the folding angle β, etc.) can be flexibly changed in actual scenarios to meet different needs.

[0053] The foldable transcranial magnetic stimulation coil provided in the aforementioned embodiment of the present application is based on the planar structure of a circular coil. By rotating the wings of the coil and changing the curvature of the surface on which the coil is located, the coil can be made to fit the human brain as closely as possible. Without sacrificing the focusing performance, the stimulation intensity and depth of the electric field can be effectively improved, and stimulation of deeper brain tissues can be achieved. This can effectively improve energy utilization, and the structure is simple, making it easy to process and manufacture.

[0054] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A folded transcranial magnetic stimulation coil, characterized in that: It comprises a left coil and a right coil, which are symmetrically arranged, wherein both the left coil and the right coil are folded along the horizontal axis and the vertical axis, and the folding angle is variable; The center line of the left coil and the right coil is taken as the x-axis, the point between the centers of the left coil and the right coil is taken as the y-axis and the y-axis coincides with the symmetry axis of the left coil and the right coil, the z-axis is perpendicular to the plane where the left coil and the right coil are located, the side where the left coil and the right coil are close to each other is the inner wing, and the other opposite side is the outer wing, and the left coil and the right coil are separated into a front wing and a rear wing with the xz plane as the dividing interface, the front wing and the rear wing of the left coil and the right coil are folded downward with the x-axis as the rotation axis, the inner wings of the left coil and the right coil remain stationary, and the outer wings are folded downward with the axes parallel to the y-axis and passing through the centers of the corresponding coils as the rotation axes.

2. The folded transcranial magnetic stimulation coil according to claim 1, characterized in that: The directions of the current flowing through the left coil and the right coil are opposite.

3. The folded transcranial magnetic stimulation coil according to claim 1, characterized in that: Both the left coil and the right coil are multi-turn structures.

4. The folded transcranial magnetic stimulation coil according to claim 1, characterized in that: The left and right coils are both copper coils.

5. The folded transcranial magnetic stimulation coil according to claim 1, characterized in that: There is a distance between the left coil and the right coil.

6. The folded transcranial magnetic stimulation coil according to claim 1, characterized in that: The original shapes of the left and right coils before folding are circular.

7. The folded transcranial magnetic stimulation coil according to claim 1, characterized in that: The coil can be scaled down or up.

8. The folded transcranial magnetic stimulation coil according to claim 1, characterized in that: The folding angle α of the front wing and the rear wing folded downward with the x-axis as the rotation axis ranges from 0° to 15°.

9. The folded transcranial magnetic stimulation coil according to claim 8, characterized in that: The inner wing remains stationary, and the outer wing is folded downward with a folding angle β ranging from 0° to 45°.

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