Yukio YAMADA

Mechanical Engineering Laboratory, Ministry of International Trade and Industry, 1-2, Namiki, Tsukuba, Ibaraki, 305-8564 Japan

(Received June 10, 2000; Accepted June 30, 2000)

This paper reviews the studies of photon migration in biological tissues and its application to optical tomography which were conducted in the Mechanical Engineering Laboratory of Japan's Ministry of International Trade and Industry. The research subjects range from theoretical and experimental studies of photon migration in random media to the development of image reconstruction algorithms and experiments for optical tomography. The most fundamental theoretical study of the photon diffusion equation has proved that the photon diffusion coefficient is independent of the absorption coefficient while the conventional one is dependent on the absorption coefficient. Experimental studies included the time-resolved spectroscopy and the fabrication of realistic human head phantoms which have five tissue types with different optical properties. Several types of reconstruction algorithms have been developed and verified experimentally. These investigations are pioneering work in the field of biomedical optics in Japan.

Key words : photon migration, biological tissue, optical tomography, photon diffusion, time-resolved spectroscopy, optical properties, scattering and absorption, optical phantom

yamada@mel.go.jp