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Optical imaging through biological tissue has the significant problems of scattering which degrades the image resolution
and quality. Research has shown that Angular Domain Imaging (ADI) improves image quality by filtering out the
scattered light in the biological tissue images based on the angular direction of photons. The advantage of this technique
is that it is independent of the wavelength, coherent, pulse, or duration compared to OCT or time domain. This allows us
to couple ADI with conventional fluorescence imaging technique. Previous work was creating test media by varying
Intralipid/water concentration to produce different scattering levels. This showed difficulties in producing a consistent
scattering medium in liquid states. Hence, ideally we want a reusable solid medium which has a stable scattering
characteristic. Our target is to investigate fluorescence ADI on skin with cancerous collagen tissue where healthy
collagen fluoresces while the cancerous collagen tissue does not. To mimic the characteristic of skin, a solid scattering
medium over a patterned fluorescence material with non-emitting structures is created. We used a solid agar medium, or
a transparent polymer, infused with Intralipid at different concentrations, as the scattering medium. The solid media with
similar scattering characteristic of skin (μs = 20cm-1, g = 0.85) is placed on top of a fluorescence plastic (415nm
excitation, ≈ 530nm emission) which is patterned by strips of non-emitting structures (200-400μm). Using small
apertures with acceptance angles of 0.171° a distance away from the solid scattering medium, these non-emitting
structures are detectable at shallow scattering tissue depth (1-2mm).
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