Advances in multiphoton microscopy for <i>in vivo</i> skin imaging and dermatologic intervention

Multiphoton microscopy (MPM) is a rapidly advancing, noninvasive optical imaging technique that enables subcellular-resolution imaging of the skin. It has shown strong potential for in vivo detection of skin cancers and other dermatologic disease. In this paper, we present an up-to-date review of recent progress in MPM for in vivo skin imaging and dermatologic interventions, with emphasis on its capabilities and current challenges. Topics include: principles and advances in MPM instrumentation; three dimensional (3D) volumetric imaging with large field of view and subcellular resolution; MPM-based diagnosis of skin cancer and skin diseases; multiphoton-absorption based photo-thermolysis; longitudinal imaging of cellular dynamics during dermatologic interventions; and recent developments in artificial intelligence for MPM image processing, including image restoration, segmentation, virtual histology, and skin disease classification.