Sensing lesions in tissues with light.

The use of light for probing and imaging of biomedical media offers the promise for development of safe, noninvasive, and inexpensive clinical imaging modalities with diagnostic ability. Various properties of light together with the ways it interacts with biological tissues may provide multiple windows to peer inside body organs. Principles and methods for extraction of information about body functions and lesions that capitalize on temporal, spectral, polarization, and spatial characteristics of transmitted light are briefly outlined. As illustrations of the potential and efficacy of light-based techniques, time-sliced and spectroscopic images of normal and cancerous human breast tissues recorded with a femtosecond Ti:sapphire laser and a broadly tunable Cr:forsterite laser, respectively, are presented.