Abstract

We present a novel fluorescence-enhanced absorption imaging algorithm for frequency-domain photon migration measurements conducted at the air-tissue interface. Fluorescence-enhanced imaging is similar to Bom iterative image reconstruction of absorption, yet it differs in that it utilizes measurements of generated fluorescence wave instead of scattered excitation wave. Using synthetic data sets, we demonstrate fluorescence-enhanced imaging for an FDA approved fluorescent agent, Indocyanine Green (ICG). Our results show the fluorescence-enhanced absorption imaging algorithm works well up to 10:1 dye uptake ratio at the modulation frequency of 100MHz. To access the noise tolerance and stability of the algorithm, the random noise of Gaussian distribution is added to the simulated measurement data, and image reconstruction is carried out. The random Gaussian noise is added to both real and imaginary parts of the fluence at the detector position at Signal-to-Noise Ratio (SNR) of 15 dB up to 55 dB. We demonstrate that the additional optical contrast from preferential partitioning of the fluorescent contrast agent and from the lifetime of dye make it more tolerant against the measurement noise when it is compared to the conventional absorption and scattering reconstruction imaging method with excitation wave information.

© 2000 Optical Society of America