Fig. 8.

Simulation. We performed a simulation in order to show that the temperature prediction is independent of the hemoglobin concentration. The simulation procedure comprised two steps. (a) In the first step, we simulated a broadband spectrum (720 to 880 nm) using certain arbitrary concentrations of hemoglobin (O2Hb, HHb, with the sum denoted as (b) tHb, (c) water (H2O), and temperature. Using this simulated spectrum, we applied PLSR to predict brain temperature based on a simulated body temperature. (d) In the second step, we then changed only the concentration of O2Hb (with a simple multiplication by 0.1) and simulated the very same spectrum (e) again. This way, we showed that while the tHb concentration changes considerably, (g) the overall temperature prediction was very similar in the two situations (h) and, hence, not affected by the change in O2Hb concentration. Concentrations are shown in arbitrary units (AU).