Innovations in two-photon deep tissue microscopy

The goal of this article is to provide a review of deep tissue studies based on two-photon microscopy. We will further explore three new developments that have significantly enhanced the power of two-photon imaging: (1) simultaneous two-photon fluorescence and confocal reflected-light imaging, (2) two-photon video-rate imaging, and (3) fluorescent spectroscopic measurements in deep tissue.