Use of bioresorbable fibers for interstitial time-domain diffuse optical spectroscopy with fast gating

Bioresorbable materials have gained interest for implantable optical components such as fibers for medical devices and have been demonstrated as suitable to perform diffuse optical measurements. In this work, we demonstrate interstitial, broadband, time-domain diffuse optical spectroscopy measurements using bioresorbable fibers, by employing a single-photon avalanche diode operated in an ultrafast time-gate mode for photon detection. Using tissue equivalent liquid phantoms, we test the system absorption linearity as per the MEDPHOT protocol and demonstrate the scattering independent absorption retrieval of the water spectrum in the 600-920 nm range. Consequently, we also attempt to distinguish the spectral changes due to the presence of optically denser speck inclusion in a tissue equivalent liquid phantom.