Diffuse optical tomography setup using a nanosecond laser

Time-domain diffuse optical tomography (TD-DOT) systems use pulsed lasers and measure time-varying temporal point spread function to estimate spatially varying optical parameters in biological tissues. Generally, the TD-DOT systems have been based on picosecond light sources and measurements were performed using photon counting methods or time-gated detectors. In this work, we demonstrate the feasibility of TD-DOT using a nanosecond laser source and measurements using a standard digital oscilloscope. For this, we constructed a prototype TD-DOT experimental system utilising a high-energy nanosecond Nd:YAG laser combined with a high-bandwidth oscilloscope. The system was used to image an optical phantom. The experiment verified that both absorbing and scattering objects can be simultaneously reconstructed with nanosecond TD-DOT.