TY - GEN
T1 - Tissue phantom studies on photon migration through fetal brain in-utero using near infra-red spectroscopy
AU - Vishnoi, Gargi
AU - Hielscher, Andreas H.
AU - Ramanujam, Nirmala
AU - Nioka, Shoko
AU - Chance, Britton
N1 - Copyright:
Copyright 2004 Elsevier Science B.V., Amsterdam. All rights reserved.
PY - 1999
Y1 - 1999
N2 - We present tissue phantom experimental results and theoretical simulations to study photon migration through the fetal head in-utero. A continuous-wave (CW), dual wavelength (760 & 850 nm) spectrometer was developed and employed for the experiments at a source-detector separation of 10 cm. Theoretical simulations were performed using time-independent, finite-difference, discrete-ordinate, radiative-transport and diffusion equations. Two phantom geometries viz. circular and rectangular were considered. The tissue phantom incorporates a fetal head (absorption coefficient, μa: 0.15 cm-1 & reduced scattering coefficient, μs': 5.0 cm-1), an amniotic fluid sac (μa=0.02 cm-1, μs'= 0.1 cm-1) and a maternal tissue layer (μa= 0.08 cm-1, μs'= 5.0 cm-1). Photon fluence from the tissue phantom was quantified as a function of fetal head depth and its position relative to probe placement. Experimental results obtained with spectrometer were found to be congruent with theoretical results and clinical investigations. The results indicate that photon fluence decreases with increase in fetal head depth for circular geometry, while it increases with increase in fetal head depth for rectangular geometry. This paradoxical result observed may be attributed to the effect of amniotic fluid in the light path. Photon fluence is sensitive for fetal head depths within 40 mm. This is well within the fetal head depths expected in near-term patients (approx. 20 mm).
AB - We present tissue phantom experimental results and theoretical simulations to study photon migration through the fetal head in-utero. A continuous-wave (CW), dual wavelength (760 & 850 nm) spectrometer was developed and employed for the experiments at a source-detector separation of 10 cm. Theoretical simulations were performed using time-independent, finite-difference, discrete-ordinate, radiative-transport and diffusion equations. Two phantom geometries viz. circular and rectangular were considered. The tissue phantom incorporates a fetal head (absorption coefficient, μa: 0.15 cm-1 & reduced scattering coefficient, μs': 5.0 cm-1), an amniotic fluid sac (μa=0.02 cm-1, μs'= 0.1 cm-1) and a maternal tissue layer (μa= 0.08 cm-1, μs'= 5.0 cm-1). Photon fluence from the tissue phantom was quantified as a function of fetal head depth and its position relative to probe placement. Experimental results obtained with spectrometer were found to be congruent with theoretical results and clinical investigations. The results indicate that photon fluence decreases with increase in fetal head depth for circular geometry, while it increases with increase in fetal head depth for rectangular geometry. This paradoxical result observed may be attributed to the effect of amniotic fluid in the light path. Photon fluence is sensitive for fetal head depths within 40 mm. This is well within the fetal head depths expected in near-term patients (approx. 20 mm).
UR - http://www.scopus.com/inward/record.url?scp=0033311208&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0033311208&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:0033311208
VL - 3597
T3 - Proceedings of SPIE - The International Society for Optical Engineering
SP - 650
EP - 660
BT - Proceedings of the 1999 Optical Tomography and Spectroscopy of Tissue III
T2 - Proceedings of the 1999 Optical Tomography and Spectroscopy of Tissue III
Y2 - 24 January 1999 through 28 January 1999
ER -