events

LAMMP/BME Seminar Series

Thursday 30th of November 2017
1:00 PM
Beckman Laser Institute Library

Biomedical Applications of Perturbation Monte Carlo Methods Dissertation Defense

Jennifer Nguyen
Math




We derive a rigorous perturbation Monte Carlo (pMC) extension that can be applied to a large family
of important biomedical light transport problems and demonstrate its greater computational efficiency
compared with using conventional Monte Carlo simulations to produce forward transport problem
solutions. The gains of the perturbation method occur because only a single baseline Monte Carlo
simulation is needed to obtain forward solutions to other closely related problems whose input is described
by perturbing one or more parameters from the input of the baseline problem. The new perturbation Monte
Carlo methods are tested using tissue light scattering parameters relevant to epithelia where many tumors
originate. The tissue model has parameters for the number density and average size of three classes of
scatterers; whole nuclei, organelles such as lysosomes and mitochondria, and small particles such
ribosomes or large protein complexes.
We have applied the pMC method to several types of forward (producing reflectance estimates for
probes with unpolarized and/or polarized light sources given a set of model parameter values) and inverse
problems (optimizing parameter values, given unpolarized and/or polarized reflectance spectra). This talk
summarizes the results of our numerical experiments with the pMC method and contains a discussion of
the computational gains acquired through our novel algorithm.