Abstract

Recently, there has been a plethora of phosphorescent and fluorescent probes developed whose lifetimes are sensitive to physiological conditions such as pH, pO₂, glucose, etc. However, to date there has been little rationale behind the use of these probes in vivo. Lifetime-based sensing in tissues and other random media depends upon deconvolving lifetimes from photon migration times which arise (i) from the propagation of excitation light from the source to the embedded probe, and (ii) from the propagation of emission light from the probe to the detecting optics. Two approaches can be envisioned: (i) to employ probes whose photon migration times are insignificant compared to phosphorescent lifetimes; and (ii) to develop approaches to determine lifetimes independently of photon migration times which are of comparable magnitudes.

© 1994 Optical Society of America