Mesh-based Monte Carlo (MMC)

Monte Carlo photon migration in complex shapes using tetrahedral meshes

• Mesh-based Monte Carlo, or MMC, is a Monte Carlo (MC) solver for photon migration in 3D turbid media. Different from existing MC software designed for layered (such as MCML) or voxel-based media (such as MMC or tMCimg), MMC can represent a complex domain using a tetrahedral mesh. This not only greatly improves the accuracy of the solutions when modeling objects with smooth/complex boundaries, but also gives an efficient way to sample the problem domain to use less memory. The current version of MMC support multi-threaded programming and can give a almost proportional speed-up when using multiple CPU cores.
• MMC was developed by Qianqian Fang at the Photon Migration Lab, Martinos Center for Biomedical Imaging, Massachusetts General Hospital (Harvard Medical School).
• Details of this software can be found in the following paper:
  • Qianqian Fang, "Mesh-based Monte Carlo method using fast ray-tracing in Plücker coordinates," Biomed. Opt. Express 1, 165-175 (2010)

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Two additional software tools are also available for download

• Collins adult brain atlas FEM mesh (Version 1, created on 06/03/2010)
• Matlab Toolbox for the Analytical Diffusion/Helmholtz Solutions of a Sphere (Version 1.0.0)

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Title

Mesh-based Monte Carlo Method Using Fast Ray-Tracing in Plücker Coordinates

Abstract

We describe a fast mesh-based Monte Carlo (MC) photon migration algorithm for static and time-resolved imaging in 3D complex media. Compared with previous works using voxel-based media discretization, a mesh-based approach can be more accurate in modeling targets with curved boundaries or locally refined structures. We implement an efficient ray-tracing technique using Plücker Coordinates. The Barycentric coordinates computed from Plücker-formed ray-tracing enables us to use linear Lagrange basis functions to model both media properties and fluence distribution, leading to further improvement in accuracy. The Plücker-coordinate ray-polygon intersection test can be extended to hexahedral or high-order elements. Excellent agreement is found when comparing mesh-based MC with the analytical diffusion model and 3D voxel-based MC code in both homogeneous and heterogeneous cases. Realistic time-resolved imaging results are observed for a complex human brain anatomy using mesh-based MC. We also include multi-threading support in the software and will port it to a graphics processing unit platform in the near future.

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