Linear and nonlinear reconstruction for optical tomography of phantoms
with nonscattering regions
(2005)Abstract
Most research in optical imaging incorrectly assumes that light transport
in nonscattering regions in the head may be modeled by use of the
diffusion approximation. The effect of this assumption is examined
in a series of experiments on tissue-equivalent phantoms. Images
from cylindrical and head-shaped phantoms with and without clear
regions simulating the cerebrospinal fluid (CSF) filled ventricles
and a clear layer (simulating the CSF layer surrounding the brain)
are reconstructed with linear and nonlinear reconstruction techniques.
The results suggest that absorbing and scattering perturbations can
be identified reliably with nonlinear reconstruction methods when
the clear regions are also present in the reference data but that
the quality of the image degrades considerably if the reference data
does not contain these features. Linear reconstruction performs similarly
to nonlinear reconstruction, provided the clear regions are present
in the reference data, but otherwise linear reconstruction fails.
This study supports the use of linear reconstruction for dynamic
imaging but suggests that, in all cases, image quality is likely
to improve if the clear regions are modeled correctly. . 2005 Optical
Society of America.