Experimental study of time-resolved measurements on turbid media: determination of optical properties and fluorescent inclusions characterization

摘要

Among the different existing techniques in optical molecular imaging, time-domain approaches can supply information on the probe concentration or localization, in case of specific fluorescent labelling. We present an experimental validation of an analytical solution to the time-domain fluorescence diffusion equation in an infinite medium. A fitting method issued from frequency domain calculations is also presented. The instrumentation employs a pulsed laser diode as light source, optical fibres, and a photomultiplier as the detector in a time correlated single photon counting (TCSPC) system. Measurements were performed on tissue simulating phantoms containing a small fluorescent inclusion, with the fibres either imbedded deep within the volume or placed at the surface, above the inclusion. Good adequacy was found between the simulations and the within medium measurements. We also demonstrate good performances of the fitting method to recover the fluorophore localization.