Time-resolved diffuse optical tomography using fast-gated single-photon avalanche diodes

Abstract

Abstract:We present the first experimental results of reflectance Diffuse Optical Tomography (DOT) performed with a fast-gated single-photon avalanche diode (SPAD) coupled to a time-correlated single-photon counting system. The Mellin-Laplace transform was employed to process time-resolved data. We compare the performances of the SPAD operated in the gated mode vs. the non-gated mode for the detection and localization of an absorbing inclusion deeply embedded in a turbid medium for 5 and 15 mm interfiber distances. We demonstrate that, for a given acquisition time, the gated mode enables the detection and better localization of deeper absorbing inclusions than the non-gated mode. These results obtained on phantoms demonstrate the efficacy of time-resolved DOT at small interfiber distances. By achieving depth sensitivity with limited acquisition times, the gated mode increases the relevance of reflectance DOT at small interfiber distance for clinical applications.

Computationally effective solution of the inverse problem in time-of-flight spectroscopy

“…Indeed the claimed precision and computational simplicity of the LKM would enable high accuracy of real-time DOS measurements for the range of optical parameters, typical for biological tissue and numerous common food products. Furthermore the LKM claims to facilitate measurements at small source to detector separations, which is highly desirable for the development of miniature probes for medical and cost-efficient industrial applications [25][26][27].…”

Time-domain diffuse optical tomography using silicon photomultipliers: feasibility study

“…Additionally, this long tail limits the dynamic range of the detector response function to about 2 orders of magnitude, 32 thus possibly affecting DOT reconstructions due to the reduced range suitable for data analysis. 34 As reported in Ref. 32, SiPMs are also characterized by high noise background (up to few hundred thousand counts per second, depending on the operating conditions), which limits the maximum number of photons per second that can be detected to avoid pile-up effects in TD acquisitions using time-correlated single-photon counting (TCSPC) systems, 20 and also, the minimum photon bunch, which can be extracted out of the noise.…”

Toward noninvasive assessment of flap viability with time-resolved diffuse optical tomography: a preclinical test on rats

“…In a previous work, 13 we presented a setup for diffuse optical tomography (DOT) based on fast-gated SPADs. High-dynamic range acquisitions were analyzed using the Mellin-Laplace transform, 13 thus obtaining tomographic reconstructions of an absorbing inclusion within the turbid medium with better depth sensitivity with respect to classical free-running (i.e., "nongated") acquisitions.…”

“…High-dynamic range acquisitions were analyzed using the Mellin-Laplace transform, 13 thus obtaining tomographic reconstructions of an absorbing inclusion within the turbid medium with better depth sensitivity with respect to classical free-running (i.e., "nongated") acquisitions. Also, we demonstrated that the adoption of short source-detector distances, combined with a fast-gated SPAD, can increase spatial resolution in DOT.…”