Monte Carlo simulations



Our research requires sophisticated tools for modelling of light propagation in highly scattering materials (photon migration). In our field of science, Monte Carlo simulation is the gold standard for modelling of light propagation. It is thus natural for us to keep improving the performance, feasibility and applicability of MC for photon migration modelling. A particular example where MC is becoming increasingly important for us is in our research on time-of-flight spectroscopy.

White Monte Carlo

In order to cover the optical properties of interest in a particular application, one might think that it is necessary to perform multiple, time-consuming MC simulations, forming a large and inconvenient database. It is, however, in some cases possible to perform a single simulation that by means of proper scaling is valid for arbitrary material properties. We perform a single MC simulation at zero absorption (hence: White Monte Carlo!) for infinite or semi-infinite materials, and can scale the results to predict light propagation for a range of scattering and absorption properties. The technique has proven very valuable in our research on time-of-flight spectroscopy (TOFS).

GPU-based Monte Carlo simulations of photon migration

Conventional CPU-based Monte Carlo simulation are very time consuming, limiting the applicability and practical value of Monte Carlo methods. In order to push our research forward, we are increasing our use of MC. In order to reduce simulation time, we are starting to use graphical processing units (GPUs). This step will render more advanced simulations feasible, as well as making MC more useful in general. Some of our simulations require weeks of simulation on a standard CPU, and we have found that GPU-based MC can reduce the simulation time significantly.

In order to promote the use of GPUs for photon migration simulations, you are free to download our code for GPU-based Monte Carlo. The code is based on the CUDA interface to NVIDIAs GPUs, and is designed to simulate time-resolved propagation in a semi-infinite and homogenously scattering material. Our results and experiences will be reported in Journal of Biomedical Optics Letters. Do not hesitate to contact us for support if you are interesting in getting started with GPU-based Monte Carlo for your application! And do not hesitate to ask questions about our implementation! This page will be updated with more information in the near future.
Download our GPU-based MC code here!

Related publications

Parallel computing with graphics processing units for high speed Monte Carlo simulation of photon migration

E. Alerstam, T. Svensson, and S. Andersson-Engels

J. Biomedical Optics Letters, accepted (15 October 2008)

Pharmaceutical and biomedical applications of spectroscopy in the photon migration regime

T. Svensson

Ph.D. Thesis (2008)

White Monte Carlo for time-resolved photon migration

E. Alerstam, S. Andersson-Engels, and T. Svensson

J. Biomedical Optics 13, 041304 (2008)

Improved accuracy in time-resolved diffuse reflectance spectroscopy

E. Alerstam, S. Andersson-Engels, and T. Svensson

Optics Express 16, 10440-10454 (2008)

Towards accurate in vivo spectroscopy of the human prostate

T. Svensson, E. Alerstam, M. Einarsdóttír, K. Svanberg, and S. Andersson-Engels

J. Biophotonics 1, 200-203 (2008)