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Proceedings Paper

Intra- and extracerebral changes of hemoglobin concentrations by analysis of moments of distributions of times of flight of photons
Author(s): Adam Liebert; Heidrun Wabnitz; Jens M. Steinbrink; Hellmuth Obrig; Michael Moeller; Rainer Macdonald; Herbert Rinneberg
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Paper Abstract

NIRS signals measured on the adult head contain contributions from the brain and from overlying tissue. It was shown recently that measured distributions of times of flight (DTOF) of photons allow to deduce absorption changes occurring in different layers of the head. This method relies on time-dependent mean partial pathlengths calculated by Monte Carlo simulations for assumed background optical properties of the various tissues. Deconvolution of the measured DTOF is required using the instrumental response function. We propose an alternative method to estimate absorption changes in various tissue layers by analyzing changes of moments of DTOFs (integral, mean time of flight and variance) recorded at various source-detector separations. The sensitivity factors corresponding to integral, mean time of flight and variance were obtained by Monte Carlo simulations for a layered model of the head. From experimentally derived mean time of flight and variance the contributions of the instrumental response function were subtracted. The proposed method was applied to multi-distance time-domain measurements during functional stimulation of the brain of healthy volunteers.

Paper Details

Date Published: 15 October 2003
PDF: 5 pages
Proc. SPIE 5138, Photon Migration and Diffuse-Light Imaging, (15 October 2003); doi: 10.1117/12.500578
Show Author Affiliations
Adam Liebert, Physikalisch-Technische Bundesanstalt (Germany)
Heidrun Wabnitz, Physikalisch-Technische Bundesanstalt (Germany)
Jens M. Steinbrink, Universitaetsklinikum Charite der Humboldt-Univ. zu Berlin (Germany)
Hellmuth Obrig, Universitaetsklinikum Charite der Humboldt-Univ. zu Berlin (Germany)
Michael Moeller, Physikalisch-Technische Bundesanstalt (Germany)
Rainer Macdonald, Physikalisch-Technische Bundesanstalt (Germany)
Herbert Rinneberg, Physikalisch-Technische Bundesanstalt (Germany)

Published in SPIE Proceedings Vol. 5138:
Photon Migration and Diffuse-Light Imaging
David A. Boas, Editor(s)

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