Advances in the simulation of light–tissue interactions in biomedical engineering

Abstract

Monte Carlo (MC) simulation for light propagation in scattering and absorbing media is the gold standard for studying the interaction of light with biological tissue and has been used for years in a wide variety of cases. The interaction of photons with the medium is simulated based on its optical properties and the original approximation of the scattering phase function. Over the past decade, with the new measurement geometries and recording techniques invented also the corresponding sophisticated methods for the description of the underlying light-tissue interaction taking into account realistic parameters and settings were developed. Applications, such as multiple scattering, optogenetics, optical coherence tomography, Raman spectroscopy, polarimetry and Mueller matrix measurement have emerged and are still constantly improved. Here, we review the advances and recent applications of MC simulation for the active field of the life sciences and the medicine pointing out the new insights enabled by the theoretical concepts.

Tutorial on methods for estimation of optical absorption and scattering properties of tissue

“…A common approach to accurately simulating the propagation of light in tissue is to use the radiative transfer equation (RTE), 16 which models the propagation of radiation through a medium affected by absorption, emission, and scattering processes. 17 Several solutions for the RTE have been proposed to date.…”

“…Due to the simplicity of the approach, it is not capable of accurately modeling multiple scattering events, making it inadequate for determining light propagation in bulk scattering media. 1 A common approach to accurately simulating the propagation of light in tissue is to use the radiative transfer equation (RTE), 16 which models the propagation of radiation through a medium affected by absorption, emission, and scattering processes. 17 Several solutions for the RTE have been proposed to date.…”

Modeling toolchain for realistic simulation of photoacoustic data acquisition

“…Solving the RTE in light–tissue interaction is done either with statistical Monte-Carlo (MC) methods or using a diffusion approximation of the RTE, which can be solved with continuum methods (e.g., finite-difference and finite element methods). 9 – 11 Next, the propagation of the pressure waves must be simulated by solving the acoustic wave equations. Many different mathematical techniques and software packages to model wave propagation of medical US have been described in the literature, often relying on spectral methods or the finite element method.…”

Inverse spectroscopic optical coherence tomography (IS-OCT) for characterization of particle size and concentration

“…In medicine and life sciences, the characterisation of light scattering, absorption and polarisation in biological tissues reveals information on their underlying structure and composition, allowing for diagnosis and monitoring in diverse applications such as arterial plaque in atherosclerosis, the size and nature of tumours, blood perfusion and oxygen saturation levels, and drug and nanoparticle delivery [1]. In particles, at the cellular and subcellular size-scale, light scattering and absorption are wavelength dependent (spectral) properties that can be described using Mie theory [2], a well-established stochastic model that forms the basis for the Monte Carlo model of multiple light-particle interactions [3][4][5][6]; alternatively, more recent scattering models also exist that include electromagnetic wave descriptions of light [7,8].…”