Results of penetration depth, superficial skin thickness calculations, and reproducibility measurements.

(a) Theoretical prediction of spectrally resolved penetration depth of TRS at each location. DCS penetration is facilitated by operating at the wavelength of maximum penetration (785nm). The inset figure shows the DEXA scan and skin caliper measurements of superficial skin thickness (mean ± SD), and the mean maximum penetration depth for TRS averaged over 630–1100 nm range and CW at 785 nm. Proximal locations show relatively lower penetration depth than distal locations. (b) Repeatability measurements on the absorption spectrum (mean ± SD) at trochanter location, illustrating robustness and repeatability. The inset reports the CV for measurements performed with the two techniques (< 5% and 25% for TRS and DCS, respectively).