Abstract

A new method for cancelling the skin blood flow in functional near-infrared spectroscopy (fNIRS) is proposed to improve the measurement accuracy of oxygen consumption in a brain tissue. We proposed to use two kinds of cancellation signals. One is a sharing aperture approach which uses cancellation signals detected at apertures for irradiating the light. Another one is an additional aperture approach which uses cancellation signals detected at the midpoint between the irradiation and detection aperture in conventional measurement. We further applied an equilateral-triangular probe arrangement to our method. For the equilateral-triangular probe arrangement, the cancellation signal of the sharing aperture approach is detected at apex, and the cancellation signal of the additional aperture approach is detected at the median point of the equilateral-triangular. Simulation and experiments with a phantom were performed. Simulation results show that the proposed method effectively detected the influence of the near-surface absorption change, which depends on its position and size, by automatically selecting the two kinds of cancellation signal.

© 2011 OSA/SPIE