Multichannel time-resolved optical tomographic imaging system

A time-resolved optical imaging system using near-infrared light has been d eveloped. The system had three pulsed light sources and total 64 channels o f detection, working simultaneously for acquisition of the time-resolved da ta of the pulsed light transmitted through scattering media like biological tissues. The light sources were provided by high power picosecond pulsed d iode lasers, and optical switches directed one of the light sources to the object through an optical fiber. The light signals reemitted from the surfa ce of the object were collected by optical fibers, and transmitted to a tim e-resolved detecting system. Each of the detecting channels consisted of an optical attenuator, a fast photomultiplier, and a time-correlated single p hoton counting circuit which contained a miniaturized constant fraction dis criminator/time-to-amplitude converter module, and a signal acquisition uni t with an A/D converter. The performance and potentiality of the imaging sy stem have been examined by the image reconstruction from the measured data using solid phantoms. (C) 1999 American Institute of Physics. [S0034-6748(9 9)04409-3].