Functional tomography using a time-gated ICCD camera

We present a system for near infrared functional tomography based on a single pulsed source and a time-gated camera, for non-contact collection over a large area. The mean penetration depth of diffusely reflected photons is dependent on the arrival time of photons, but not on the source–detector distance. Thus, time-encoded data can be used to recover depth information while photon exiting point is exploited for lateral localization. This approach was tested against simulations, demonstrating both detection and localization capabilities. Preliminary measurements on inhomogeneous phantoms showed good detection sensibility, even for a low optical perturbation, and localization capabilities, yet with decreasing spatial resolution for increasing depths. Potential application of this method to in vivo functional studies on the brain is discussed.