This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We have assembled a table-top experimental setup to develop various novel techniques for the clinical LSS imaging system. The light source is a 300W Xenon Arc Lamp. A monochromator (Oriel Cornerstone) steps wavelength of excitation light with 10nm FWHM spectral line width. The light is then collimated. The spatial pattern of the excitation is determined by a mask which is imaged on the sample by a 4-f system consisting of two lenses with focal length of 40 cm. The polarization of the excitation is controlled by a polarizer. The excitation angles can be selected. The scattering from the sample comes back along the path of the excitation before it is deflected by a beam splitter into the collection path. This collection beam passes through an iris which selects permitted backscattering angles. Both excitation and collection angle ranges are about 0.5 . Another polarizer determines the polarization of the light collected by the CCD. It is designed to spectrally image an area of ex-vivo tissue in the lab. Modeling of the light intensity spectral modulations by means of Mie theory provides information about the tissue morphology (particle size distribution) and optical properties (refractive index). The system has been mounted on an optical table, and the alignment and LSS operation are tested. The data acquisition is fully automated. Data is analyzed and compared with simulated results. Preliminary spatial images are obtained from a suspension with polystyrene beads on top of an intralipid gel providing diffusive background. The results show backscattering features in good agreement with predictions from Mie
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