biostudies-literatureParfentyeva VGeneralitat de CatalunyaISCIIIEuropean UnionLUX4MED special program“Severo Ochoa” Programme for Centres of Excellence in R&DFEDER ECAgencia Estatal de InvestigaciónFundació Mir-PuigFundació CELLEX BarcelonaSME Instrument SQPTV3 La Marato11982https://www.ebi.ac.uk/biostudies/studies/S-EPMC10366131biostudies-literatureUnknown13(1)Time-domain diffuse correlation spectroscopy (TD-DCS) has been introduced as an advancement of the "classical" continuous wave DCS (CW-DCS) allowing one to not only to measure depth-resolved blood flow index (BFI) but also to extract optical properties of the measured medium without using any additional diffuse optics technique. However, this method is a photon-starved technique, specially when considering only the late photons that are of primary interest which has limited its in vivo application. In this work, we present a TD-DCS system based on a superconducting nanowire single-photon detector (SNSPD) with a high quantum efficiency, a narrow timing response, and a negligibly low dark count noise. We compared it to the typically used single-photon avalanche diode (SPAD) detector. In addition, this system allowed us to conduct fast in vivo measurements and obtain gated pulsatile BFI on the adult human forehead.Scientific reportsFast time-domain diffuse correlation spectroscopy with superconducting nanowire single-photon detector: system validation and in vivo results.PMC10366131848827871124Lanka PParfentyeva VRe RPifferi ANoordzij NDalla Mora AContini DColombo LKolarczik MDurduran TTorricelli ABrodu APagliazzi MfalseFast time-domain diffuse correlation spectroscopy with superconducting nanowire single-photon detector: system validation and in vivo results.Time-domain diffuse correlation spectroscopy (TD-DCS) has been introduced as an advancement of the "classical" continuous wave DCS (CW-DCS) allowing one to not only to measure depth-resolved blood flow index (BFI) but also to extract optical properties of the measured medium without using any additional diffuse optics technique. However, this method is a photon-starved technique, specially when considering only the late photons that are of primary interest which has limited its in vivo application. In this work, we present a TD-DCS system based on a superconducting nanowire single-photon detector (SNSPD) with a high quantum efficiency, a narrow timing response, and a negligibly low dark count noise. We compared it to the typically used single-photon avalanche diode (SPAD) detector. In addition, this system allowed us to conduct fast in vivo measurements and obtain gated pulsatile BFI on the adult human forehead.2023-01-01T00:00:00Z2023 Jul2025-04-05T14:52:28.212Z2025-04-05T14:52:28.212ZS-EPMC103661313748818810.1038/s41598-023-39281-5