Elliptical Magnetic Stimulation Coil for Focused Cortex Targeting
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Solution Overview
Problem
Existing magnetic stimulation coils for repetitive transcranial magnetic stimulation (rTMS) face challenges in focusing the magnetic field intensity on the desired brain regions while minimizing unwanted stimulation of surrounding muscles, leading to patient discomfort, and are limited by conductor overheating and power supply constraints.
Innovation Solution
A stimulation coil design with symmetrical halves, divided into a central region with closely arranged linear turns and a refluent region with elliptical turns, optimized to concentrate magnetic field intensity at a depth of 2-3 cm below the surface, reducing lateral lobes and using an air core to prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the intensity of magnetic stimulation is increased to improve therapeutic efficacy, then the therapeutic effect is enhanced, but unwanted stimulation of surrounding muscles occurs causing patient discomfort
Solution Approach 1:
The coil is divided into two separate circular windings placed side by side, allowing independent optimization of each winding to focus the magnetic field on the motor cortex while minimizing lateral spread to surrounding muscles
Solution Approach 2:
The coil design creates localized magnetic field concentration under the center of the coil by optimizing the current distribution and geometric arrangement, producing high intensity focus at the target region while reducing intensity in surrounding areas
2Reliability
If conventional circular stimulation coils are used to stimulate appropriate cortex structures, then the magnetic field can be applied, but it is difficult to ensure the vector of induced electrical voltage is parallel to the surface of the skull
Solution Approach 1:
The single circular coil is segmented into two separate circular windings placed side by side, which can be independently positioned and oriented to better align with the curvature of the skull surface, making it easier to achieve parallel orientation of the induced voltage vector with the skull surface
Solution Approach 2:
The coil design transitions from a single-plane circular winding to a two-dimensional arrangement of two separate circular windings, enabling better adaptation to the three-dimensional curvature of the skull surface
3Illumination intensity
If stimulation coils with iron core are used to focus the magnetic field, then field concentration is improved, but the magnetic induction is limited to about 2 Tesla due to saturation
Solution Approach 1:
The iron core is removed from the coil design, eliminating the magnetic saturation limitation and allowing the magnetic induction to exceed 2 Tesla by using air core construction, while still achieving field concentration through the optimized geometric arrangement of the two circular windings
4Measurement precision
If the coil design is optimized to focus magnetic field at a depth of 2-3 cm below the surface, then therapeutic precision is improved, but the complexity of conductor arrangement increases
Solution Approach 1:
The complex requirement for precise deep brain stimulation is segmented into two simpler circular windings placed side by side, each contributing to the focal field generation. This segmentation simplifies the conductor arrangement while maintaining the ability to focus the magnetic field at the desired depth of 2-3 cm below the surface
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design enhances magnetic field focus on the motor cortex, reduces unwanted muscle stimulation, and addresses power limitations by optimizing conductor arrangement and using an air core, improving therapeutic efficacy and patient comfort.
Implementation Method 1
the magnetic stimulation is an established term used generally for stimulation of any nerve structures, including those of the brain, mainly for diagnostic and research purposes, by means of an induced electrical voltage, the voltage is induced by a rapid change of a strong magnetic induction over time
Data Source
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AI summary
A magnetic stimulation coil (1) for a magnetic stimulation, the stimulation coil having a winding split into two symmetrical halves, a left half (2a) and a right half (2b), both halves are arranged next to each other and pressed against each other, wherein the windings of each half (2a, 2b) of the stimulation coil (1) is formed by a set of turns (T1 to Tm) made of a conductor, wherein said stimulation coil (1) is having one side (5) intended for performing the stimulation. Each half (2a, 2b) of the winding is formed by at least three tiers (L1 to Ln) of turns arranged on each other, said conductor in a given tier, wherein each tier (L1 to Ln) is formed by a group of conductor turns (T1 to Tm), wherein, all tiers (L1 to Ln) of each one winding half (2a, 2b) of said winding are connected in series and have the same direction of the conductor rotation, wherein said direction of conductor rotation is opposite in each half (2a, 2b) of the winding. The turns of the conductor are arranged in an elliptical shape in each tier of the winding and the turns (T1 to Tm) of the winding in the individual tiers (L1 to Ln) widen in the region of the vertices of the longer half-axes of the ellipse from the side intended for magnetic stimulation with regard to the turns of the winding in the previous tier in the direction from the side (5) intended for performing of the magnetic stimulation.