Fig. 3

(A) Mean effective optical density spectra of PTG obtained during the surgery, measured before and after thyroid removal. The translucent areas indicate the standard deviation. The legend indicates the calculated oxygenation indices (SpO2) for the mean spectra. (B) Representative decomposition of the experimental OD spectrum (orange dots) into the sum of the absorption spectra of deoxyhemoglobin (green dashed line) and oxyhemoglobin (red dashed line) and a straight-line representing the light scattering (black dashed line). (C) Box plots of PTG oxygenation indices before (blue) and after (orange) thyroid removal for different surgeries, with PTH values measured before and after surgery shown above.