Multi-channel time-resolved tissue oximeter for functional imaging of the brain

We report the development and characterization of a novel multichannel time-resolved instrument for functional brain imaging studies. The instrument is based on picosecond diode lasers, fiber optics for light injection and delivery, a compact multianode photomultiplier and a PC board for time-correlated single photon counting. The instrument has been characterized in term of reproducibility among the 9 sources and the 12 collection channels, linearity in the determination of optical properties (absorption and reduced scattering), and stability. Preliminary in vivo measurements were performed on volunteers to monitor the optical response to stimuli following motor (finger opposition, 5 Hz) or cognitive task (word generation).