Fig. 5.

Handheld and semi-handheld PAM systems and the corresponding results. (A) The schematic of raster (A) and rotatory (B) scanning mechanisms. A-line (red): 1D depth-resolved signal. B-scan (gray): a cross-sectional image consisting of serial A-lines along the optical scanning path (green line). (C) The system configuration of a handheld photoacoustic microscope employing the raster scanning mechanism with a fast 2D galvanometer scanner [102]. SMF, single mode fiber. GS, galvanometer scanner. FC, fiber collimator. OL, objective lens. Z, Z-direction stage. XY, XY direction stage. G, glass. UT, ultrasonic transducer. DAQ, data acquisition, FPGA, field-programmable gate array. (D) The volumetric rendering of subcutaneous blood vessels of a human lower lip acquired by the handheld PAM [102]. (E) In vivo imaging of subcutaneous vasculatures of a human wrist. MAPs of normal skin (upper) and vascular nevus (lower) indicated by the blue and red boxes in the photograph are shown respectively [102]. (F) The schematic of a rotatory-scanning semi-handheld OR-PAM system combing with a universal arm [104]. BS, beam splitter. PD, photodiode. Obj, objective. P, pinhole. L, convex lens. SMF, single mode fiber; CG, cover glass; IL, imaging lens; GVS, galvanometer scanner; LB, laser beam. (G) A photograph of in vivo imaging experiments of a rabbit and the corresponding MAPs of ear (i) and eye (ii and iii) [104]. (H) In vivo oral imaging of a volunteer and recovery progress of an oral ulcer in the lip. Scale bar, 1 mm [104]. Reprinted with permission from Ref. [102,104]. (For interpretation of the references to colour in the Figure, the reader is referred to the web version of this article).