TY - JOUR
T1 - Dynamic phantom with two stage-driven absorbers for mimicking hemoglobin changes in superficial and deep tissues
AU - Funane, Tsukasa
AU - Atsumori, Hirokazu
AU - Kiguchi, Masashi
AU - Tanikaw, Yukari
AU - Okada, Eiji
PY - 2012/4
Y1 - 2012/4
N2 - In near-infrared spectroscopy (NIRS) for monitoring brain activity and cerebral functional connectivity, the effect of superficial tissue on NIRS signals needs to be considered. Although some methods for determining the effect of scalp and brain have been proposed, direct validation of the methods has been difficult because the actual absorption changes cannot be known. In response to this problem, we developed a dynamic phantom that mimics hemoglobin changes in superficial and deep tissues, thus allowing us to experimentally validate the methods. Two absorber layers are independently driven with two one-axis automatic stages. We can use the phantom to design any type of waveform (e.g., brain activity or systemic fluctuation) of absorption change, which can then be reproducibly measured. To determine the effectiveness of the phantom, we used it for a multiple source-detector distance measurement. We also investigated the performance of a subtraction method with a short-distance regressor. The most accurate lower-layer change was obtained when a shortest-distance channel was used. Furthermore, when an independent component analysis was applied to the same data, the extracted components were in good agreement with the actual signals. These results demonstrate that the proposed phantom can be used for evaluating methods of discriminating the effects of superficial tissue.
AB - In near-infrared spectroscopy (NIRS) for monitoring brain activity and cerebral functional connectivity, the effect of superficial tissue on NIRS signals needs to be considered. Although some methods for determining the effect of scalp and brain have been proposed, direct validation of the methods has been difficult because the actual absorption changes cannot be known. In response to this problem, we developed a dynamic phantom that mimics hemoglobin changes in superficial and deep tissues, thus allowing us to experimentally validate the methods. Two absorber layers are independently driven with two one-axis automatic stages. We can use the phantom to design any type of waveform (e.g., brain activity or systemic fluctuation) of absorption change, which can then be reproducibly measured. To determine the effectiveness of the phantom, we used it for a multiple source-detector distance measurement. We also investigated the performance of a subtraction method with a short-distance regressor. The most accurate lower-layer change was obtained when a shortest-distance channel was used. Furthermore, when an independent component analysis was applied to the same data, the extracted components were in good agreement with the actual signals. These results demonstrate that the proposed phantom can be used for evaluating methods of discriminating the effects of superficial tissue.
KW - Automatic stage
KW - Biological tissue
KW - Cerebral blood
KW - Dynamic phantom
KW - Independent component analysis
KW - Multidistance measurement
KW - Near-infrared spectroscopy
KW - Scalp blood
KW - Scanning system
KW - Systemic fluctuation
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UR - http://www.scopus.com/inward/citedby.url?scp=84865610173&partnerID=8YFLogxK
U2 - 10.1117/1.JBO.17.4.047001
DO - 10.1117/1.JBO.17.4.047001
M3 - Article
C2 - 22559692
AN - SCOPUS:84865610173
VL - 17
JO - Journal of Biomedical Optics
JF - Journal of Biomedical Optics
SN - 1083-3668
IS - 4
M1 - 047001-1
ER -