RESUMO
Fast time-gated single-photon detectors demonstrated high depth sensitivity in the detection of localized absorption perturbations inside scattering media, but their use for in vivo clinical applications-such as functional imaging of brain activation-was impaired by their small (<0.04mm2) active area. Here, we demonstrate, both on phantoms and in vivo, the performance of a fast-gated digital silicon photomultiplier (SiPM) that features an overall active area of 8.6mm2, overcoming the photon collection capability of established time-gated single-pixel detectors by orders of magnitude, enabling deep investigations within scattering media and high signal-to-noise ratios at late photon arrival times.
RESUMO
Two main bottlenecks prevent time-domain diffuse optics instruments to reach their maximum performances, namely the limited light harvesting capability of the detection chain and the bounded data throughput of the timing electronics. In this work, for the first time to our knowledge, we overcome both those limitations using a probe-hosted large area silicon photomultiplier detector coupled to high-throughput timing electronics. The system performances were assessed based on international protocols for diffuse optical imagers showing better figures with respect to a state-of-the-art device. As a first step towards applications, proof-of-principle in-vivo brain activation measurements demonstrated superior signal-to-noise ratio as compared to current technologies.