WE‐E‐304A‐04: Local Determination of Tissue Optical Properties: Reconstruction Based On Fiber‐Array Reflectance Profiles

Quantitative evaluation of in vivo local tissue optical properties including scattering coefficient (μs), absorption coefficient (μa) and anisotropy (g) is often important in both photodiagnosis and phototherapy. In this study, a reflectance based fast technique was developed to determine the optical properties of turbid media using a linear‐array fiber bundle probe. Five 200 um collection fibers were linearly set along from the 200 um illumination fiber with center‐to‐center separation of 350 um. Spatial reflectance values were sequentially measured by spectrometer connected to a fiber‐switch. A model that relates the reflectance profiles to optical properties of a turbid medium was developed based on Monte Carlo simulations and phantom experiments. Simulation results at wavelength of 633 nm showed that μs′ (2∼40 cm−1) and μa (0∼5 cm−1) can be determined by reflectance spatial profiles. Intralipid and Nigrosin were used to simulate different reduced scattering coefficient (μs′) and absorption coefficient (μa) values within the same range as Monte Carlo simulation. Preliminary results show good correlation between known optical properties in tissue phantom and the measured optical properties, the average error for μs′ and μa was 7.8% and 6.6%, respectively. With same reduced scattering coefficient (μs′), changes in the absorption coefficient (μa) could be measured within 0.1 cm−1. Accurate extraction of tissue optical properties from in vivo measurements could have potential application in noninvasively superficial (pre)cancer detection and phototherapy planning.