Clinical Nonlinear Laser Imaging of Human Skin: A Review

Figure 3

Layer-by-layer characterization of epidermis. TPF image of NADH autofluorescence and the corresponding FLIM images representing mean lifetime map acquired from the epidermis of a healthy male volunteer at 25 μm depth from skin surface ((a), (b)), 40 μm depth from skin surface ((c), (d)), and 55 μm depth from skin surface ((e), (f)). The images are approximately corresponding to granular layer ((a), (b)), spinous layer ((c), (d)), and basal layer ((e), (f)). Images were acquired in the epidermis of a healthy male volunteer by using an excitation wavelength of 740 nm. Laser power, measured after the objective, is indicated in the down-left corner of each image. Field of view: 60 μm. Scale bar: 6 μm. Mean cellular lifetime distribution (g) and mean cellular lifetime components ratio (h) of the 3 different epidermal layers obtained after system response deconvolution and double-exponential fitting.