A Ray Optics Framework for the Computation of The Sieve Effect Factor for Blood
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Date
2010-01-20T16:40:01Z
Authors
Northam, Lesley
Journal Title
Journal ISSN
Volume Title
Publisher
University of Waterloo
Abstract
Light may traverse a turbid material, such as blood, without encountering any of its
pigment particles, a phenomenon known as sieve effect. This phenomenon may result in a
decrease in the amount of light absorbed by the material. Accordingly, the corresponding
sieve factor needs to be accounted for in optical investigations aimed at the derivation of
blood biophysical properties from light transmittance measurements. The existing procedures
used for its estimation either lack the flexibility required for practical applications or
are based on general formulas that incorporate other light and matter interaction phenomena.
In this thesis, a ray optics framework is proposed to estimate the sieve factor for blood
samples using a first principles approach. It consists in applying ray-casting techniques
to determine the probability that light can traverse a blood sample without encountering
any of the pigment (hemoglobin) containing cells. The thickness of the samples as well
as the distribution, orientation and shape of the red blood cells are taken into account by
the simulation algorithm employed in this framework. The predictive capabilities of the
proposed approach are demonstrated through a series of in silico experiments. Its effectiveness
is further illustrated by visualizations depicting the different blood parameterizations
considered in the simulations.
Description
Keywords
blood, optics, sieve effect