In earlier studies, we developed scattering models and the corresponding CPU-based Monte Carlo simulation programs to study the behavior of polarized photons as they propagate through complex biological tissues. Studying the simulation results in high degrees of freedom that created a demand for massive simulation tasks. In this paper, we report a parallel implementation of the simulation program based on the compute unified device architecture running on a graphics processing unit (GPU). Different schemes for sphere-only simulations and sphere-cylinder mixture simulations were developed. Diverse optimizing methods were employed to achieve the best acceleration. The final-version GPU program is hundreds of times faster than the CPU version. Dependence of the performance on input parameters and precision were also studied. It is shown that using single precision in the GPU simulations results in very limited losses in accuracy. Consumer-level graphics cards, even those in laptop computers, are more cost-effective than scientific graphics cards for single-precision computation.
We report an anisotropic tissue model containing well-ordered birefringent cylinders. Using simulations and experiments, we examined the different polarization features for nonbirefringent and birefringent cylinders and analyzed the influence of the birefringent cylinders on the retardance obtained from Mueller matrix polar decomposition. For the well-ordered birefringent cylinders, retardance increases linearly with the intrinsic birefringence and the scattering coefficient. Furthermore, the cylinders with a larger diameter generate more retardance. Compared with the cylinder-birefringence model, in which birefringent medium exists between the scatterers, the intrinsic birefringence on the cylinders usually contributes much less to the total retardance.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.