Extinction coefficient (ε) is a critical parameter for quantification of oxy-, deoxy-, and total-hemoglobin concentrations (Δ[HbO2], Δ[Hb], Δ[tHb]) from optical measurements of Near-infrared spectroscopy (NIRS). There are several different ε data sets which were frequently used in NIRS quantification. A previous study reported that even a small variation in ε could cause a significant difference in hemodynamic measurements. Apparently the selection of an optimal ε data set is important for NIRS. We conducted oxygen-state-varied and blood-concentration-varied model experiments with 57 human blood samples to mimic tissue hemodynamic variations. Seven reported ε data sets were evaluated by comparisons between quantifications and assumed values. We found that the Moaveni et al (1970)’ ε data set was the optimal one, the NIRS quantification varied significantly among different ε data sets and parameter Δ[tHb] was most sensitive to ε data sets selection.

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Published in Biomedical Optics Express, v. 8, no. 11, p. 5151-5159.

©2017 Optical Society of America

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National Natural Science Fund Projects (No.61675039) CAMS Innovation Fund for Medical Sciences (No. 2016-I2M-3-023) One University One Zone Growth Fund (No. A03013023001019) Fundamental Research Funds for the Central Universities (No. ZYGX2016J052).