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Frequency-domain measurements of photon migration in tissues

✍ Scribed by Joseph R. Lakowicz; Klaus Berndt

Publisher
Elsevier Science
Year
1990
Tongue
English
Weight
506 KB
Volume
166
Category
Article
ISSN
0009-2614

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✦ Synopsis

We report the use of frequency-domain (FD) measurements to characterize time-dependent migration of 620-740 nm photons in tissues, in particular arm and finger. The time dependence of the re-emerged light appears to be characterized by a delay time which depends on path length and detector geometry, a transient-time spread which appears to depend on sample homogeneity, and an exponential decay time which depends on sample absorbance and/or path length. The time delay is revealed by a phase angle exceeding 90", which is not explainable for directly initiated multi-or single-exponential processes. The transit-time spread is revealed by a frequency-dependent decrease in modulation which is more rapid than for an exponential decay. Potential clinical uses of the FD photon migration measurements are discussed.

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