Single-fiber diffuse optical time-of-flight spectroscopy

Alerstam, Erik; Svensson, Tomas; Andersson‐Engels, Stefan; Spinelli, Lorenzo; Contini, Davide; Mora, Alberto Dalla; Tosi, Alberto; Zappa, Franco; Pifferi, Antonio

doi:10.1364/ol.37.002877

Cited by 38 publications

(36 citation statements)

References 16 publications

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“…Thanks to this feature, a single measurement is sufficient to directly uncouple absorption from scattering contributions, thus leading -for a homogeneous medium -to the absolute quantification of both absorption and reduced scattering coefficients. Further, in the case of reflectance geometry, with light source and detection points placed on the same side of the medium at a relative distance ρ, the mean penetration depth of detected photons steadily increases upon increasing the photon arrival time [39,40], thus permitting deep tissue imaging even at null-ρ [41][42][43] with the chance to reach a record level of source-detector couples coverage to maximize the detected signal and the spatial resolution, provided that an efficient time-gating mechanism is employed to avoid the blinking burst of undesired early-arriving photons [44][45][46]. However, the main limitations of TD as compared to CW systems during the last two decades have always been high cost and complexity, thus affecting the maximum number of injection and detection channels, and wider deployment of instruments for clinical use.…”

Section: Discussionmentioning

confidence: 99%

Fast silicon photomultiplier improves signal harvesting and reduces complexity in time-domain diffuse optics

Mora¹,

Martinenghi²,

Contini³

et al. 2015

Opt. Express

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Abstract:We present a proof of concept prototype of a time-domain diffuse optics probe exploiting a fast Silicon PhotoMultiplier (SiPM), featuring a timing resolution better than 80 ps, a fast tail with just 90 ps decay time-constant and a wide active area of 1 mm 2 . The detector is hosted into the probe and used in direct contact with the sample under investigation, thus providing high harvesting efficiency by exploiting the whole SiPM numerical aperture and also reducing complexity by avoiding the use of cumbersome fiber bundles. Our tests also demonstrate high accuracy and linearity in retrieving the optical properties and suitable contrast and depth sensitivity for detecting localized inhomogeneities. In addition to a strong improvement in both instrumentation cost and size with respect to legacy solutions, the setup performances are comparable to those of state-of-the-art time-domain instrumentation, thus opening a new way to compact, low-cost and high-performance time-resolved devices for diffuse optical imaging and spectroscopy.

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Section: Discussionmentioning

confidence: 99%

Fast silicon photomultiplier improves signal harvesting and reduces complexity in time-domain diffuse optics

Mora¹,

Martinenghi²,

Contini³

et al. 2015

Opt. Express

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“…Additionally, bioresorbable fibers can be profitably coupled with fast-gated detectors [39] to reject the peak of reflected or scarcely diffused photons that can saturate the dynamic range of a "classical" (i. e. non-gated) detector, thus allowing the use of a single interstitial fiber as already demonstrated in the case of classical optical fibers [40].…”

Section: Conclusion and Future Perspectivesmentioning

confidence: 99%

Towards the use of bioresorbable fibers in time‐domain diffuse optics

Sieno

Boetti

Mora

et al. 2017

Journal of Biophotonics

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In the last years bioresorbable materials are gaining increasing interest for building implantable optical components for medical devices. In this work we show the fabrication of bioresorbable optical fibers designed for diffuse optics applications, featuring large core diameter (up to 200 mm) and numerical aperture (0.17) to maximize the collection efficiency of diffused light. We demonstrate the suitability of bioresorbable fibers for timedomain diffuse optical spectroscopy firstly checking the intrinsic performances of the setup by acquiring the instrument response function. We then validate on phantoms the use of bioresorbable fibers by applying the MEDPHOT protocol to assess the performance of the system in measuring optical properties (namely, absorption and scattering coefficients) of homogeneous media. Further, we show an ex-vivo validation on a chicken breast by measuring the absorption and scattering spectra in the 500-1100 nm range using interstitially inserted bioresorbable fibers. This work represents a step toward a new way to look inside the body using optical fibers that can be implanted in patients. These fibers could be useful either for diagnostic (e. g. for monitoring the evolution after surgical interventions) or treatment (e. g. photodynamic therapy) purposes. Picture: Microscopy image of the 100 mm core bioresorbable fiber.

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“…The active area is considerably smaller (20 µm -500 µm) but it is often compensated by the other advantages especially if the sample has limited emission geometry (like in confocal microscopy [9], scanning systems [10] or fiber-based endoscopy [11]). …”

Section: Introductionmentioning

confidence: 99%

Time-resolved singlet-oxygen luminescence detection with an efficient and practical semiconductor single-photon detector

Boso¹,

Ke²,

Korzh³

et al. 2015

Biomed. Opt. Express

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Abstract:In clinical applications, such as PhotoDynamic Therapy, direct singlet-oxygen detection through its luminescence in the near-infrared range (1270 nm) has been a challenging task due to its low emission probability and the lack of suitable single-photon detectors. Here, we propose a practical setup based on a negative-feedback avalanche diode detector that is a viable alternative to the current state-of-the art for different clinical scenarios, especially where geometric collection efficiency is limited (e.g. fiber-based systems, confocal microscopy, scanning systems etc.). The proposed setup is characterized with Rose Bengal as a standard photosensitizer and it is used to measure the singlet-oxygen quantum yield of a new set of photosensitizers for site-selective photodynamic therapy. Tower, and J. Ferraro, "Geiger-mode avalanche photodiode focal plane arrays for three-dimensional imaging LADAR," Proc. SPIE 7808, 78080C

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Single-fiber diffuse optical time-of-flight spectroscopy

Cited by 38 publications

References 16 publications

Fast silicon photomultiplier improves signal harvesting and reduces complexity in time-domain diffuse optics

Fast silicon photomultiplier improves signal harvesting and reduces complexity in time-domain diffuse optics

Towards the use of bioresorbable fibers in time‐domain diffuse optics

Time-resolved singlet-oxygen luminescence detection with an efficient and practical semiconductor single-photon detector

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