Hybrid light method reveals how camera signals can probe blood flow in deeper tissues

How can we efficiently collect light returning from tissues while also identifying what it tells us about blood flow in the deeper tissues? Conventional interferometric near-infrared spectroscopy (iNIRS) can distinguish signals according to the amount of time that light takes to travel through tissue, but it collects only a few photons. Camera-based systems capture many more photons, but this distinction is not realized when living tissue changes rapidly. Researchers associated with ICTER combined both approaches in a hybrid system. They showed that an appropriately analyzed camera signal can reproduce the blood-flow response observed with iNIRS for late-arriving photons, which are more sensitive to deeper tissues.