Time-Resolved multi-wavelength, dual-channel system for diffuse optical spectroscopy: performance assessment

In this paper we present the ex-vivo characterization of a full-custom made multi-wavelength, two channel Time-Resolved Spectroscopy (TRS) module developed with the aim of being integrated in to a multi-modal spectroscopic device. This module overcomes all the main drawbacks of systems based on time-domain techniques such as high complexity and bulkiness while guaranteeing performances comparable to expensive state-of-the-art available devices. Each subcomponent of the module has been tailored and optimized to meet all the above-mentioned requirements. In order to assess and translate the performances of these tools for effective clinical use, we characterized the system following the guidelines of common standardization protocols. By following MEDPHOT guidelines, the linearity and accuracy in retrieving absolute values of absorption and scattering coefficients were determined by means of measurements on homogeneous phantoms. Finally, by means of a mechanically switchable solid inhomogeneous phantom (developed under the nEUROPT project) we simulated the clinical problem of detecting and localizing an absorption perturbation in a homogeneous background with broad applications such as detection of cancer lesions, thyroid, etc.