28 April 2005 Determination of particle size distribution from tissue using light scattering spectroscopy with small source detector separations
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The ability to retrieve particle size information from back scattering reflectance with a small source-detector separation would significantly enhance the potential for development of non-invasive and minimally invasive diagnostic techniques. We present a technique for inverse determination of particle size distribution and volume fractions and validate it with polystyrene microspheres. Two of monotonic, third-degree polynomial equations were fitted from Mie theory to relate wavelength exponent 'n' and particle radii. These two equations allow us to inversely estimate the particle size from the measured 'n' value. A genetic algorithm was applied to optimize the particle size distribution and volume fraction. The experimental setup consisted of a tungsten light, CCD spectrometer with a bifurcated optical fiber for light delivery and detection. The measurement system was calibrated with a reflectance standard; different sizes and volume fractions of the suspensions were chosen for measurements. The wavelength dependence of reduced scattering coefficient was derived from the measured reflectance. Polystyrene microsphere suspensions with diameters 0.43 - 2.00 μm were characterized using the developed algorithm. The results show a good agreement between the particle size retrieved by our algorithm and manufacturer’s data, demonstrating a robust method for particle size determination using near infrared reflectance and small source-detector separation.
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Dheerendra Kashyap, Cole A. Giller, Hanli Liu, "Determination of particle size distribution from tissue using light scattering spectroscopy with small source detector separations", Proc. SPIE 5693, Optical Tomography and Spectroscopy of Tissue VI, (28 April 2005); doi: 10.1117/12.592835; https://doi.org/10.1117/12.592835

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