Would near-infrared fluorescence signals propagate through large human organs for clinical studies?

We predict the capacity of near-infrared fluorescent signals to propagate through human tissue for non-invasive medical imaging. This analysis employs experimental measurements of a biologically relevant local fluorochrome embedded in tissuelike media and predicts the equivalent photon counts expected from breast, lung, brain, and muscle as a function of diameter by use of an analytical solution of the diffusion equation that can take into account large arbitrary geometries. The findings address feasibility issues for clinical studies and are relevant to recent development of near-infrared fluorescent probes and molecular beacons for in vivo applications. (C) 2002 Optical Society of America.