Effects of photodamage on ex vivo human cerebellum tissue during label-free multiphoton imaging.

A: Single high quality image of a Purkinje cell acquired using CARS (red) and TPEF (green) at laser excitation power ∼52 mW. B: Further serial scanning of the area indicated by the dotted-line box in A resulted in a gradual increase in TPEF. The cell body is shown after 30, 164 and 272 scans. The photodamage-induced TPEF developed first in the tissue around the cell body and then also inside the cell cytoplasm. C: TPEF difference images (corresponding to the images in B) obtained subtracting the TPEF image of the first scan from the TPEF images at 30, 164 and 272 scans respectively; they underline the photodamage-induced TPEF around the cell (see scan 164) and in the cell cytoplasm (see scan 272).