ANYL 289 |
| There are many instances that require the knowledge of the Scattering Coefficient (μS), Absorption Coefficient (μA) and Anisotropy (g). An example of where these measurements are critical is in the identification and characterization of tissues in-vivo or ex-vivo. This knowledge is also useful in developing equipment and reagents for clinical diagnostic tasks by allowing one to predict their success for a given scenario. To accurately predict the success or feasibility of a new technology involving biomedical optics it is critical to understand how the sample scatters, absorbs and transports light. The focus of this work is on the use of a commercial UV-Vis-NIR Spectrometer to measure Total Transmission, Total Reflectance and Collimated Transmission in order to calculate μS, μA and g. Experiments are performed on NIST traceable polystyrene beads suspended in water. With the polystyrene beads as a standard, we see excellent agreement with values calculated by MIE theory. The method used is adapted from one previously suggested by Scott Prahl of the Oregon Medical Laser Center. Once the values of Total Transmission, Total Reflectance and Collimated Transmission are measured, the Inverse Adding Doubling solution to the Radiative Transport Equation is used to solve for albedo, optical thickness and anisotropy. Upon finding these three values, rudimentary calculations yield the optical constants of interest. The benefit of this method is that it uses a commercial spectrometer equipped with an integrating sphere, requiring minimal light path modification, while most experiments of this type are normally done using a laser based approach with an optical bench. Measurement of these constants can now be performed on a routine basis, which allows for accurate diffusely scattering optical phantom design for the diffuse optical imaging community as well as helping to cross-validate measurements done on different instruments. |
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Analytical Approaches
8:30 AM-12:00 PM, Tuesday, 28 March 2006 Georgia World Congress Center -- B215, Oral
Sci-Mix
Division of Analytical Chemistry |