Optical property measurement of thin superficial tissue by using time-resolved spectroscopy

Recently, non-invasive diagnostic devices using infrared light have been developed and widely use for clinical applications. To develop these devices, optical properties of biological tissue are necessary. We proposed a new optical measurement method. By using time-resolved reflectance spectroscopy and Monte Carlo simulation for the analysis of light propagation in sample, it is considered that this new method is able to measure the optical properties of small biological tissues in vivo. In this study, we investigated the possible optical property measurements of a superficial layer using this new method. As the later part of the profile of time-resolved reflectance is influenced by the optical property of the deeper layer, a time-gating technique is necessary for the measurement of the optical properties of only the superficial layer in order to use the early profile of the time-resolved reflectance measurement. The function f(t), which is described in the new method, is used for evaluation of the measurement of the superficial layer. We suggest that by using the time-gating technique for the new method and a small source-detector spacing, the optical properties of the superficial layer with a thickness is more than source-detector spacing, can be obtained.