Multi-Coil TMS Focusing for Precise Brain Region Targeting
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Solution Overview
Problem
Current transcranial magnetic stimulation (TMS) techniques face challenges in achieving precise control over magnetic field strength and penetration depth, leading to unwanted stimulation of adjacent neurons and difficulty in identifying specific brain regions, due to variable coil positioning and electromagnetic properties.
Innovation Solution
A system utilizing a dynamically configurable arrangement of solenoids, referred to as the Figure-of-Flower Coil (FFC), allows for selective focusing and steering of the electric field by individually modulating solenoid feed currents, enabling precise control over magnetic field distribution and penetration depth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic field strength is increased to achieve desired stimulation results in target region, then stimulation effectiveness is improved, but unwanted stimulation of adjacent neurons increases
Solution Approach 1:
The patent applies local quality by using multiple solenoids with individually controllable current magnitudes and phases to create a non-uniform magnetic field distribution. This allows the field strength to be locally optimized at the target region while maintaining lower strength in adjacent regions, thereby achieving effective stimulation of the target while minimizing unwanted stimulation of surrounding neurons.
Solution Approach 2:
The patent segments the magnetic field generation into multiple independent solenoids rather than using a single coil. Each solenoid can be independently controlled in terms of current magnitude and phase, enabling precise spatial control over the magnetic field distribution. This segmentation allows the field to be concentrated at the target region while reducing exposure to adjacent areas.
2Measurement precision
If control of focality and penetration depth is attempted through multiple variables, then field precision is improved, but difficulty in achieving optimal set-up increases
Solution Approach 1:
The patent changes the control parameters from mechanical positioning variables to electrical control variables. By controlling the current magnitude and phase of each solenoid independently, the system can adjust focality and penetration depth through electrical parameters rather than requiring precise mechanical positioning of a single coil. This simplifies the setup process while maintaining or improving field precision.
Solution Approach 2:
The patent implements feedback control by using a processor to calculate optimal current magnitudes and phases for each solenoid based on desired field characteristics. The system can adjust the electrical parameters in real-time to achieve the desired focality and penetration depth, reducing the need for manual positioning adjustments and improving ease of operation.
3Device complexity
If fixed and rigid E-field is provided by traditional TMS coils, then system simplicity is maintained, but adaptability to different target regions is reduced
Solution Approach 1:
The patent transforms the static, fixed E-field of traditional TMS coils into a dynamic, adjustable field by using multiple solenoids with independently controllable current magnitudes and phases. This allows the E-field to be dynamically repositioned and reshaped to target different brain regions without changing the physical coil configuration, greatly enhancing adaptability while maintaining manageable system complexity through electronic control.
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 system provides high focality and adjustable E-field placement, reducing unwanted stimulation and enhancing the accuracy of TMS by allowing for precise targeting of specific brain regions with improved control over magnetic field strength and depth.
Implementation Method 1
time-varying magnetic fields produced by TMS coils positioned outside a subject's head induce an electric field (E-field) within the subject's brain
Implementation Method 2
generating a Q-element solenoid feed modulation state vector that defines a Q-current element feed current modulation state, configured to cause the zone-specific set of Q solenoids to generate a corresponding Q individual, spatially configured, time-varying magnetic fields
Data Source
AI summary
An example method includes positioning above the transcranial region, an arrangement of solenoids, and selecting a target zone from among a plurality of zones. A zone-specific set of Q solenoids is identified from the arrangement of solenoids, based on the target zone. The zone-specific set includes a pair of mutually adjacent ones of the solenoids. A Q-element solenoid feed modulation state vector is generated, which defines a Q-current element feed current modulation state. The Q-current element feed current modulation state is configured to cause the zone-specific set of Q solenoids to generate Q individual, spatially configured, time-varying magnetic fields that, in combination, establish a transcranial magnetic stimulation (TMS) inducing time-varying magnetic field, which induces a target hotspot TMS electric field. The hotspot TMS electric field is focalized to the target zone.