The laser-scanning-based clinical multiphoton tomograph, MPTflex (JenLab GmbH, Germany) consists of a compact, turn-key femtosecond laser (MaiTai Ti:Sappire oscillator, sub-100 fs, 80 MHz, tunable 690–1020 nm; Spectra Physics, Mountain View, California), an articulated arm with NIR optics, and a beam scanning module. The system has two photomultiplier tube detectors employed for parallel acquisition of TPEF and second-harmonic generation (SHG) signals. A customized metallic ring taped on the subject’s skin attaches magnetically to the objective holder in the articulated arm, minimizing motion artifacts. The excitation wavelengths used for this study were 790 nm for the acquisition of the cross-sectional () images and 880 nm for the acquisition of the z-stacks of horizontal () images. The z-stacks were obtained by moving the objective in the z direction, thus scanning at different depths in the skin. The TPEF signal was detected over the spectral range of 410–650 nm, while the SHG signal was detected over a narrow spectral bandwidth of 385–405 nm through emission filters placed in the TPEF and SHG detection channels, respectively. The sections were pixel images acquired at . The sections were pixel images acquired at . We used a Zeiss objective (, 1.3 NA, oil immersion) for focusing into the tissue.