Improvement of near-infrared topography by optode arrangement and reconstruction algorithm using spatial sensitivity profile

Near-infrared topographic imaging can noninvasively measure the distribution of brain activation in the cortex. The near-infrared light is strongly scattered in the superficial tissues and the volume of tissue sampled by a source-detector pair of the imaging system is broadly distributed in the cortical tissue. This poses results in poor spatial resolution and contrast in the topographic images. In this study, we propose reconstruction algorithm for near-infrared topographic imaging using the spatial sensitivity profile. The profile of absorption change in the head model is calculated to evaluate the proposed algorithm. The width of the profiles calculated by the proposed algorithm is smaller than that by the conventional mapping algorithm. The profiles calculated by the proposed algorithm agree with the correct distribution when the interval of the source-detector pairs is less than 8 mm.