Yukio YAMADA¹ and Shinpei OKAWA²

¹Brain-Inspired Life Support Research Center, The University of Electro-Communications, Chofu, Tokyo 182-8585, Japan
²Department of Medical Engineering, National Defense Medical College, Tokorozawa, Saitama 359-8513, Japan

(Received October 17, 2013; Accepted February 21, 2014)

Diffuse optical tomography (DOT) is one of the emerging modalities for the non-invasive imaging of thick biological tissues using near-infrared (NIR) light. This article reviews the fundamentals and development of DOT technology since its advent in the early 1990s, including the modeling of light propagation in biological tissues which strongly scatter and weakly absorb NIR light, the optical properties of biological tissues in the NIR wavelength range, three typical measurement methods, image reconstruction algorithms, and so forth. Then various studies are referred to for improvement of the DOT images, which are essentially low in quality due to the ill-conditioned and underdetermined problem. Studies and clinical applications presently attracting much attention are discussed in some detail. Finally, the expected future developments are summarized.

Key words: diffuse optical tomography, light propagation, turbid media, inverse problem, breast imaging, brain imaging, molecular imaging