This work investigates the design of optimum distribution of photon density power among the source positions, and optimum modulation frequencies to maximize the detectability of heterogeneities embedded in turbid medium using near infrared light. The optimum waveforms are designed for the sources in near-infrared diffuse optical tomography which involves reconstruction of spatially varying optical properties of turbid medium as well as fluorophore lifetime and yield from boundary measurements. We start our analysis by first deriving the discrete source-to-detector map based on the finite-element formulation of the diffuse photon density wave equation and Robin boundary conditions. We determine statistical figures of merit to maximize the contrast of heterogeneities with respect to a given background. Next, we design optical waveforms that will maximize the figure of merit for the detectability of heterogeneities. When the figure of merit is derived based on optimal linear detection under the assumption of Gaussianity, the optimal source vector is given by the eigenvector corresponding to the maximum eigenvalue of the norm of the differences between the source-to-detector maps of homogeneous and heterogeneous domains. We extended our approach to investigate the optimum spatial positions and intensities of point sources to maximize the detectability of the heterogeneities. We explored the effect of tumor location with respect to the sources, tumor size, and the number of sources on detectability.

Date Published: 6 March 2006
PDF: 11 pages
Proc. SPIE 6139, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XV, 61391A (6 March 2006); doi: 10.1117/12.647209

Published in SPIE Proceedings Vol. 6139:
Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XV
David Kessel, Editor(s)