The scattering properties and refractive indices (RI) of tissue are important parameters in tissue optics. These parameters can be determined from quantitative phase images of thin slices of tissue blocks. However, the changes in RI and structure of cells due to fixation and paraffin embedding might result in inaccuracies in the estimation of the scattering properties of tissue. In this study, three-dimensional RI distributions of cells were measured using digital holographic microtomography to obtain total scattering cross sections (TSCS) of the cells based on the first-order Born approximation. We investigated the slight loss of dry mass and drastic shrinkage of cells due to paraformaldehyde fixation and paraffin embedding removal processes. We propose a method to compensate for the correlated changes in volume and RI of cells. The results demonstrate that the TSCS of live cells can be estimated using restored cells. The percentage deviation of the TSCS between restored cells and live cells was only −8%. Spatially resolved RI and scattering coefficients of unprocessed oral epithelium ranged from 1.35 to 1.39 and from 100 to 450 cm−1, respectively, estimated from paraffin-embedded oral epithelial tissue after restoration of RI and volume.
The progression of epithelial dysplasia is accompanied by changes of sub-cellular structures which alter light scattering,
particularly backscattering, properties of epithelial cells. In this study, we quantified the refractive index (RI)
distributions of normal and cancerous epithelial cells of skin and oral cavity using digital holographic microtomography
and investigated the backscattering characteristics of the cells using finite-difference time-domain simulations. The
results show that cancerous cells present higher average values of nuclear and nucleolar RI and a higher standard
deviation of cytoplasmic RI than normal cells. Both the total scattering and backscattering cross-sections of the
cancerous cells are significantly higher than those of the normal cells.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.