Comparison of Transcranial Magnetic Stimulation Dosimetry between Structured and Unstructured Grids Using Different...

Area of Science:

• Biomedical Engineering
• Computational Neuroscience
• Medical Physics

Background:

• Transcranial magnetic stimulation (TMS) interest is growing, requiring accurate low-frequency (LF) numerical dosimetry.
• Commercial software like SimNIBS and Sim4Life are popular for TMS dosimetry.
• Previous studies often lacked realism in anatomical models and exposure scenarios.

Purpose of the Study:

• To compare the accuracy of LF solvers in SimNIBS and Sim4Life for TMS dosimetry.
• To assess the performance of these tools across simplified and realistic anatomical models.
• To evaluate the reliability of computational dosimetry for TMS applications.

Main Methods:

• Utilized SimNIBS (tetrahedral mesh) and Sim4Life (voxel-based mesh) with finite element method (FEM) solvers.
• Compared induced electric fields in three models: single-shell sphere, sphere with slab, and MRI-derived head model.
• Analyzed discrepancies in electric field calculations across different model complexities.

Main Results:

• Small discrepancies in induced electric fields were observed between the two software tools.
• Differences were minimal in simpler models (below 2%) and moderate in the head model (below 12%).
• Discrepancies were primarily noted in regions of low electric field intensity.

Conclusions:

• Both SimNIBS and Sim4Life are valuable computational tools for TMS dosimetry.
• The study confirms the potential of these tools for advancing TMS exposure assessment.
• Accurate dosimetry is crucial for developing and refining TMS protocols in biomedical applications.