MPT is a novel label-free clinical imaging method based on femtosecond laser technology. MPT has the best resolution of all tomography methods providing optical biopsies and optical metabolic images with chemical information for rapid in vivo histology. MPT tissue images are based on two-photon autofluorescence, second harmonic generation (SHG), fluorescence lifetimes and Raman (CARS) signals.
Multiphoton effects have been predicted by the PhD student Maria Goeppert in the twenties of the last century. However, it took more than 30 years to prove her theory. In 1961, one year after the first laser was invented, Kaiser et al. demonstrated two-photon excited fluorescence. Shortly after the introduction of a first ultrashort laser microscope in the eighties in Jena, Denk et al. published in 1990 on a two-photon microscope for cell imaging. Piston et al. and König et al. investigated the cellular autofluorescence and Masters et al. the tissue autofluorescence with a two-photon microscope. In 2003, the first peer-reviewed publication (König and Riemann) on a clinical two-photon imaging system, a so-called multiphoton tomograph “DermaInspect”, appeared.