Modelling Light Propagation in Skin

Figure 1. Light propagating into tissue from a fibre source at the surface.

Modelling light propagation in tissue provides a means of investigating instruments and mechanisms that may be useful for the diagnosis of pigmented skin lesions. This modelling relies on knowledge of the optical properties and structure of the skin at a very fine scale. Information about tissue optical properties must be collected from a wide range of sources including direct and indirect measurements of tissue, measurements of isolated components such as water or hemoglobin, and inferential extraction of properties based on other modelling work.

At OBEL, modelling was used to investigate light propagation to and from our clinical system's probe so that the area of sensitivity could be matched to correlated histopathology. Further work included design of optimal probe geometries and characterisation of the system's sensitivity to different pathologies. This modelling was usually combined with confirming experiments.

The modelling system used at OBEL is based on a locally modified and extended version of the MCML Monte Carlo software developed by Lihong Wang and Steven L. Jacques.

Figure 2. Modelling the photon fluence near our probe. Fluence levels are proportional to system sensitivity .