Exposure Analysis

Summary:

The Exposure Analysis step provides a complete Sim4Life (ZMT Zurich MedTech AG) workbench — including Modeling, Simulation, and Analysis sections. Users can load TI and HF field distributions exported from TI Analysis, reconstruct and adjust electrode montages, run new electromagnetic simulations, and perform in-depth visualization and dosimetry analysis. Ready-to-use template projects are provided for all precomputed anatomical models.

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Sim4Life Documentation & Tutorials

Note: Since Exposure Analysis provides a full Sim4Life workbench, the complete Sim4Life documentation, training materials, and video tutorials apply directly and are a valuable resource for getting the most out of this step.

Resource	Description
Sim4Life Support & Documentation	Official page with user manuals, product flyers, training materials, and support resources
How-To Video Playlist	Full collection of how-to and tutorial videos on the ZMT Zurich MedTech AG YouTube channel

Overview

Starting with TIP V5.0, the Exposure Analysis step exposes a full Sim4Life workbench with all three sections available:

• Modeling: Full geometric and meshing capabilities. The electrode montage identified during TI Analysis optimization can be reconstructed and adjusted on the subject model.
• Simulation: Configure and run new simulations — either to investigate a specific electrode configuration in detail, or to recreate the full lead-field library from scratch.
• Analysis: All visualization and post-processing tools — volume rendering, slicing, iso-surfaces, streamlines, masking, histograms, and more.

Available Input Files

The files pre-loaded in Exposure Analysis depend on the pipeline path:

Input	Contents
input_1/	TI and HF field .cache files exported from TI Analysis via Export to S4L
input_2/	Subject .smash model file (personalized: from the Personalizer; precomputed: from the template library)
input_3/	DTI tensor data, if available (personalized anisotropic models only)

The subject model forwarded to Exposure Analysis is determined by the previous step: once a subject is selected in the TI Analysis dropdown and Load is clicked, the corresponding .smash file (and DTI tensors, where available) are automatically forwarded.

Typical Workflow

1. Run the SuMo optimizer in TI Analysis to identify the best electrode configurations.
2. Select a configuration of interest and click Export to S4L to generate the .cache field file.
3. Proceed to Exposure Analysis.
4. In the Analysis section, load the .cache file to inspect the field distribution.
5. Switch to the Modeling section — the subject's .smash model is already available in input_2/. Set up or adapt the electrode montage for the chosen configuration.
6. Switch to the Simulation section to run a targeted simulation for that montage.
7. Return to the Analysis section for a detailed investigation of the simulated fields.

Template Projects for Precomputed Models

For every precomputed (non-personalized) anatomical model available in TIP, a ready-to-use Sim4Life template project is provided. Each template includes:

• The full anatomical model with all tissue entities defined and labeled.
• All standard targets (brain structures) pre-configured.
• All standard electrode positions pre-placed on the scalp surface.
• A pre-configured template multiport simulation that can be used to:
  • Recreate the full lead-field library by running all 61 basis simulations as-is.
  • Investigate a specific configuration by adapting the montage identified during TI Analysis optimization.

Available precomputed models with template projects:

Model	Variants
MIDA (human)	Isotropic, Anisotropic
IXI Female	Anisotropic
IXI Male	Anisotropic
Mouse	Isotropic