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 optimised the detection probability of singly scattered photons from small depths. The sampling depth of this delivery-and-collection fiber was investigated by use of a tissue phantom. We found that for our phantom 90% of the single-scattering signal in the delivery-and-collection fiber originated from less than 200 microm 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 probes sensitivity to light scattering from superficial layers of tissue and thereby its potential to detect superficial precancerous epithelial lesions.