16 July 2015 Non-contact scanning time-domain functional optical imaging of the adult human brain
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We developed a novel scanning system that relies on gated detection of late photons at short source-detector separation, enabling the recording of absorption changes in deep tissue compartments. The tissue was scanned by a galvanometer scanner from a distance of more than 10 cm, with a fixed separation of the illumination and the detection spot of a few mm. The light source was a supercontinuum laser with an acousto-optic tunable filter that was used to rapidly switch between two wavelength bands centered at 760 nm and 860 nm. A fast-gated single-photon avalanche diode was employed to eliminate the intense early part of the diffusely remitted signal and to detect photons with long times of flight with improved signal-to-noise ratio. A second detection channel contained a non-gated detector. The gated and non-gated time-of-flight distributions of photons were recorded by imaging time-correlated single photon counting synchronized with the movement of the scanner. A tissue area with dimensions of several cm was scanned with 32×32 pixels within a frame time of 1 s. Sensitivity and spatial resolution of the system were characterized by phantom measurements. In-vivo tests included functional brain activation by various tasks and demonstrated the feasibility of non-contact imaging of hemodynamic changes in the cerebral cortex.
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Heidrun Wabnitz, Heidrun Wabnitz, Mikhail Mazurenka, Mikhail Mazurenka, Katja Fuchs, Katja Fuchs, Laura Di Sieno, Laura Di Sieno, Gianluca Boso, Gianluca Boso, Davide Contini, Davide Contini, Alberto Dalla Mora, Alberto Dalla Mora, Alberto Tosi, Alberto Tosi, Yoko Hoshi, Yoko Hoshi, Antonio Pifferi, Antonio Pifferi, Rainer Macdonald, Rainer Macdonald, } "Non-contact scanning time-domain functional optical imaging of the adult human brain", Proc. SPIE 9538, Diffuse Optical Imaging V, 953802 (16 July 2015); doi: 10.1117/12.2183288; https://doi.org/10.1117/12.2183288


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