Combined non‐linear laser imaging (two‐photon excitation fluorescence microscopy, fluorescence lifetime imaging microscopy, multispectral multiphoton microscopy) in cutaneous tumours: first experiences

Background  Two‐photon excitation (TPE) fluorescence microscopy is a high‐resolution laser‐scanning imaging technique enabling deep imaging inside biological tissues. TPE microscopy has the triple advantage of offering high spatial resolution (250 nm radially, 800 nm axially), high penetration depth inside skin (200mm ), and low photodamage effects. Further, cells and extracellular matrix intrinsically contain a variety of fluorescent molecules (NADH, tryptophan, keratins, melanin, elastin, cholecalciferol and others), so that biological tissues can be imaged by TPE microscopy without any exogenous probe.