Shaped TMS Coils for Deep Brain Stimulation
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Solution Overview
Problem
Conventional Transcranial Magnetic Stimulation (TMS) electromagnets with figure-8 shaped coils face challenges in achieving deep brain stimulation due to limited magnetic field depth and specificity, making focal stimulation of the brain beneath the cortical surface difficult.
Innovation Solution
The use of non-linear, curved or bent coils forming a 'V', 'U', or 'Y' shape to create TMS electromagnets that balance focality and power delivery, with specific configurations such as Y-shaped coils having a vertex where windings from both coils are parallel and electrically connected, allowing current to flow in the same direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If conventional figure-8 shaped coils are used for TMS, then the electromagnet structure is simple and easy to manufacture, but the magnetic field depth and focality are limited, making deep brain stimulation difficult
Solution Approach 1:
The patent applies curvature by bending the conventional flat figure-8 coils into three-dimensional curved configurations. The coils are formed with arcs, segments, and curved portions that extend in multiple directions (including Z-axis curvature), transforming the magnetic field generation from a planar to a volumetric configuration. This curvature enables the magnetic field to penetrate deeper into the brain while maintaining focality, directly resolving the contradiction between field depth and coil structure simplicity.
Solution Approach 2:
The patent transitions from two-dimensional flat coils to three-dimensional spatial configurations. The bent coils are arranged in multiple planes and orientations, with segments extending in different directions (anterior-posterior, left-right, and superior-inferior axes). This dimensional expansion allows the magnetic field to be focused on deep brain structures while the coil itself occupies a compact form factor, balancing field depth with device complexity.
2Measurement precision
If conventional circular or double circular coils are used, then the manufacturing process is straightforward, but magnetic field strength declines rapidly with distance from the coil face, limiting focal stimulation capability
Solution Approach 1:
The patent divides the coil into multiple discrete segments or turns that can be independently positioned and oriented. Each segment is a separate conductive element that contributes to the overall magnetic field generation. This segmentation allows for precise control of current flow paths and magnetic field distribution, enabling enhanced field strength at target depths while maintaining manufacturability through modular construction approaches.
Solution Approach 2:
The patent implements local quality by varying the coil geometry and current distribution in different regions. Specific segments are positioned at different orientations and distances from the target, with varying numbers of turns and conductive properties optimized for local field generation requirements. This allows enhanced magnetic field strength at deep brain targets while keeping the overall coil design manufacturable through standardized fabrication processes.
3Shape
If bent or curved coil configurations are used to improve magnetic field depth, then deep-brain stimulation capability is enhanced, but the balance between focality and power level delivery becomes more difficult to achieve
Solution Approach 1:
The patent incorporates dynamic control capabilities through adjustable parameters including variable current amplitudes, pulse widths, and frequencies that can be optimized for different target depths and tissue characteristics. The coil configuration includes adjustable segments and turns that can be independently controlled to dynamically balance focality and power delivery. This dynamic adaptability allows the system to optimize performance for specific deep brain targets while maintaining manufacturability through standardized hardware design.
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
These shaped coil configurations result in improved magnetic field penetration to depth, providing a focused magnetic field suitable for deep-brain TMS, overcoming the limitations of conventional designs by enhancing both focality and power delivery to targets beneath the cortical surface.
Implementation Method 1
a first bent magnetic coil loop comprising a plurality of windings and a second bent magnetic coil loop comprising a plurality of windings
Implementation Method 2
the first and second inner coil regions are arranged to form a vertex configured so that the plurality of windings within the first inner coil region for a column this is adjacent and parallel to the plurality of windings within the second inner coil
Data Source
AI summary
Described herein are shaped coil TMS electromagnets formed by two bent magnetic coil loops joined at a vertex having an angle between the outer coil regions of the coils that is typically less than 120 degrees (e.g., between about 45 and about 70 degrees, 60 degrees, etc.). The vertex region shaped to optimize the magnetic field projected from the TMS electromagnet. For example, the vertex region may be horizontal or vertical. In some variations the vertex region is formed by re-arranging the conductive windings forming the two coils so that they are no longer arranged in the same columnar structure that they are in the other portions of the bent magnetic coil loops. These TMS electromagnets may be well suited for use in deep-brain Transcranial Magnetic Stimulation.