Figure 8.

Tissue penetration experiments

(A) and (B) are the experimental detection images of penetrating pigskin and HAP, respectively.

(C) ML spectra after passing through different thicknesses of pigskins, which increases 5 mm each time from 0 to 30 mm. The inset is the integrated ML intensities over the spectral range of 870–970 nm of these spectra shown in (C).

(D) ML spectra passing through HAP pellet and the background signal. Reproduced with permission from (Xiong et al., 2019a). Copyright 2019 The American Ceramic Society.