PMC

Schematic of the photoacoustic microscope used in the described experiments.

(a) Photo of a nevus located on the forearm of the volunteer. (b) B-scan PA image taken along the blue dashed line in (c). Notable features including the nevus, epidermal–dermal junction, and subpapillary blood vessels, are all labeled. (c) MAP image of a nevus acquired using 570 nm laser illumination. The nevus is clearly shown in “green scale,” and blood vessels are shown in red. The blue dashed line indicates the cross-section shown in (b) and the yellow dashed line indicates the cross-section depicted in Fig. . (d) MAP image of a nevus acquired with a 700 nm laser excitation wavelength. The yellow line indicates the cross-section shown in Fig. . (Color online only.)

(a) Photo of the palm of the volunteer. The red box indicates the imaged area 8 mm × 8 mm. (b) B-scan PA image taken along the dashed line in (c). Notable features including the stratum corneum, epidermal–dermal junction, and subpapillary blood vessels, are all labeled. Selected vessels have been labeled with color arrows for reference with the image in (c). (c) Maximum amplitude projection PA image taken from the palm using a 584 nm laser excitation wavelength. The green dashed line indicates the cross-section shown in (b). (Color online only.)

(a) Photo of the forearm of the volunteer. The red box indicates the imaged area 8 mm × 8 mm. (b) B-scan PA image taken along the dashed line in (c). Notable features, including the epidermal–dermal junction and subpapillary blood vessels, are labeled. Selected vessels have been labeled with color arrows and for reference the image in (c). (c) Maximum amplitude projection PA image taken from the forearm using a 584 nm laser excitation wavelength. The green dashed line indicates the cross-section shown in (b). (Color online only.)

(a) Maximum amplitude projection of a nevus generated from serial histology sections (top view, i.e., en face view, of the nevus) used to match histology with PA data. The nevus is shown in red, and a large hair follicle near the top was used to orient the image with the PA MAP image. (b) Histology section along the dashed line in (a), in which the location of the nevus thickness is indicated by the dashed line and two hash marks. A blood vessel used for orientation is circled in green. [(c) and (d)] Cross-sectional PA images of the nevus in the approximate region as (b) and are marked in Figs. , . (c) Image acquired with 570 nm laser illumination. The blood vessel circled in green matches with the vessels outlined in (b). (d) Image acquired using 700 nm laser illumination. The red dashed lines in both images (c) and (d) indicate the depth profiles shown in (e) and (f). Depth profile plots of the nevus are indicated by the dashed line in the cross-sectional images in (c) and (d). (e) Profile plot from the image acquired with a 570 nm laser excitation wavelength shows the nevus thickness to be 270 μm. (f) Profile plot from the image acquired with a 700 nm laser excitation wavelength shows the nevus thickness to be 262 μm. (Color online only.)