1 July 2006 Time-gated optical system for depth-resolved functional brain imaging
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We present a time-domain optical system for functional imaging of the adult head. We first describe the instrument, which is based on a Ti:Sapphire pulsed laser (wavelength 750–850 nm) and an intensified CCD camera enabling parallel detection of multiple fibers. We characterize the system in terms of sensitivity and signal-to-noise ratio, instrument response function, cross-talk, stability, and reproducibility. We then describe two applications of the instrument: the characterization of baseline optical properties of homogeneous scattering media, and functional brain imaging. For the second application, we developed a two-part probe consisting in two squares of 4×4 sources and 3×3 detectors. The laser source is time-multiplexed to define 4 states of 8 sources that can be turned on during the same camera frame while minimizing cross-talk. On the detection side, we use for each detector 7 fibers of different lengths creating an optical delay, and enabling simultaneous detection in 7 windows (by steps of 500 ps) for each detector. This multiple window detection allows depth sensitivity. The imaging probe was tested on dynamic phantoms and a preliminary result on an adult performing a motor task shows discrimination between superficial and cortical responses to the stimulus on both hemispheres.
© (2006) Society of Photo-Optical Instrumentation Engineers (SPIE)
Juliette J. Selb, Juliette J. Selb, Danny Kalathil Joseph, Danny Kalathil Joseph, David A. Boas, David A. Boas, } "Time-gated optical system for depth-resolved functional brain imaging," Journal of Biomedical Optics 11(4), 044008 (1 July 2006). https://doi.org/10.1117/1.2337320 . Submission:

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