<title>The empiristic theory of photon migrating in local tissue and estimation of the optical properties from reflectance measurement</title>

Abstract

In order to increase the spatial resolve of measuring the optical properties of local tissue, the source-detector separation should be decreased. However, in this case, the diffuse approximation theory is invalid to describe the photon migration of local tissue, and could not use to attain the optical properties of tissue from the reflectance measurements. The Monte-Carlo method is used to simulate the photon migration in turbid media, but the inverse problem is very complex. Therefore, we try to give an approximation formula to describe the photon migration in this condition and attain the optical properties. In this paper, a novel optical detecting system was introduced to measure the optical properties of local tissue, which employed 1-D fiber array, and the maximum of light source-detector separation to collecting fiber can be confined in 1 mm. Based on the measurement of the different concentration intralipid, and an empiristic model was established to show the relationship between the separator-dependant reflectance and optical properties, which well agreed with Monte-Carlo simulation. Ulteriorly, the optical properties were derived from the empiristic model, the error from this approximation theory were analyzed. The results demonstrate that the empiristic theory can be used to describe the photon migration in local tissue and rapidly acquire the optical properties of local tissue.