Single-Scattering Spectroscopy for the Endoscopic Analysis of Particle Size in Superficial Layers of Turbid Media

We report on the development of an optical-fiber-based diagnostic tool that is sensitive to single-scattering events close to the fiber-optic probe tip. By using a single fiber to deliver and detect white light we optimized the detection probability of singly scattered photons from small depths. The sampling depth of this delivery-andcollection fiber was investigated by use of a tissue phantom. We found that for our phantom 90% of the singlescattering signal in the delivery-and-collection fiber originated from less than 200 (mu)m from the fiber tip. The contribution of multiply scattered light from a greater depth to the signal was measured with an additional collection fiber. Several tissue phantoms demonstrated our fiber-optic probe’s sensitivity to light scattering from superficial layers of tissue and thereby its potential to detect superficial precancerous epithelial lesions.