Shuping WANG, Nanae SHIBAHARA, Daishi KURAMASHI, Shinpei OKAWA, Naoto KAKUTA¹, Eiji OKADA², Atsushi MAKI³, and Yukio YAMADA

Department of Mechanical Engineering and Intelligent Systems, University of Electro-Communications, 1-5-1 Chofuga-oka, Chofu, Tokyo 182-8585, Japan
¹Department of Energy Science and Engineering, School of Engineering, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
²Department of Electronics and Electrical Engineering, Keio Univeristy, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
³Advanced Research Laboratory, Hitachi Ltd., 2520 Akanuma, Hatoyama, Saitama 350-0395, Japan

(Received August 26, 2009; Accepted May 7, 2010)

In order to investigate the effects of anatomical variation in human heads on the optical mapping of brain activity, we perform simulations of optical mapping by solving the photon diffusion equation for layered-models simulating human heads using the finite element method (FEM). Particularly, the effects of the spatial variations in the thicknesses of the skull and cerebrospinal fluid (CSF) layers on mapping images are investigated. Mapping images of single active regions in the gray matter layer are affected by the spatial variations in the skull and CSF layer thicknesses, although the effects are smaller than those of the positions of the active region relative to the data points. The increase in the skull thickness decreases the sensitivity of the images to active regions, while the increase in the CSF layer thickness increases the sensitivity in general. The images of multiple active regions are also influenced by their positions relative to the data points and by their depths from the skin surface.

Key words: optical mapping, anatomy of human head, photon diffusion equation, skull layer, CSF layer