Analysis of ICCD time-gated images through turbid media using a perturbative model

Abstract

Optical imaging through turbid media has gathered a great interest as a non-invasive method to localize tumors inside the body. A step forward in this direction could be provided by a parallel detector that allows one to acquire a huge amount of data in a short time. This could result in a more stable reconstruction of the optical properties of the sample and in a more reliable diagnosis. We used a system based on a fast gated intensified CCD camera capable of a gate width <200 ps to acquire time sliced images of the light transmitted though a phantom simulating the optical properties of the human breast. Light pulses emitted by a laser diode (633 nm) were delivered to the central position of the phantom, while the output plane was imaged by the ICCD (fan geometry). Experimental data were analyzed using an analytical expression for homogeneous medium and a perturbative model, both derived from the Random Walk Theory (RWT). By using the perturbative approach we evaluated the depth (along Z axis) of scattering inclusions and their scattering coefficient