Photon migration through fetal head in utero using continuous wave, near-infrared spectroscopy: development and evaluation of experimental and numerical models

TitlePhoton migration through fetal head in utero using continuous wave, near-infrared spectroscopy: development and evaluation of experimental and numerical models
Publication TypePeer Reviewed Archived Journal Publications
Year of Publication2000
AuthorsVishnoi, G, Hielscher, AH, Ramanujam, N, Chance, B
JournalJ Biomed Opt
Volume5
Pagination163-72
Date PublishedApr
ISBN Number1083-3668 (Print)1083-3668 (Linking)
Accession Number10938780
Keywords*Models, Theoretical, *Photons, *Spectroscopy, Near-Infrared, Cerebrovascular Circulation, Diffusion, Female, Fetal Blood/metabolism, Fetus/*anatomy & histology/metabolism, Head/blood supply/*embryology, Humans, Image Processing, Computer-Assisted, Oxygen/blood, Phantoms, Imaging, Pregnancy, Scattering, Radiation, Sensitivity and Specificity, Uterus
Abstract

In this work experimental tissue phantoms and numerical models were developed to estimate photon migration through the fetal head in utero. The tissue phantoms incorporate a fetal head within an amniotic fluid sac surrounded by a maternal tissue layer. A continuous wave, dual-wavelength (lambda = 760 and 850 nm) spectrometer was employed to make near-infrared measurements on the tissue phantoms for various source-detector separations, fetal-head positions, and fetal-head optical properties. In addition, numerical simulations of photon propagation were performed with finite-difference algorithms that provide solutions to the equation of radiative transfer as well as the diffusion equation. The simulations were compared with measurements on tissue phantoms to determine the best numerical model to describe photon migration through the fetal head in utero. Evaluation of the results indicates that tissue phantoms in which the contact between fetal head and uterine wall is uniform best simulates the fetal head in utero for near-term pregnancies. Furthermore, we found that maximum sensitivity to the head can be achieved if the source of the probe is positioned directly above the fetal head. By optimizing the source-detector separation, the signal originating from photons that have traveled through the fetal head can drastically be increased.

URLhttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=10938780
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