| Popis: |
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). |
