Diagnostic System and Methods for Simultaneously Detecting Light at Multiple Detection Locations in a Spectroscopic System

A device and system for non-invasively measuring wavelength-dependent changes in optical absorption of brain tissue damaged by CTE, TBI, concussion, repetitive trauma, and/or Lou Gehrig's disease in comparison to signals from healthy normal tissue for a subject in vivo. The brain, tissues, and fluids superficial to the brain are trans-cranially illuminated by light source(s) in low-absorption spectral windows for tissue in the visible and/or near-infrared parts of the spectrum. Optode(s) are disposed at predetermined radial distance(s) from a light output to collect the scattered and/or deflected signal from the surface of the head. The predetermined radial distance from the light output to the optode is correlated with the depth of tissue penetration for the light collected by the optode. A spectrometer and computer analyze the collected light for characteristic optical signatures of the brain tissue damage utilizing the absorbance and/or reflectance and/or transmission spectra generated as a result.