Detection of Tissue Anomalies and Cancer

The most often used optical non-invasive techniques for the detection of anomalies in living tissue are optical coherence tomography (OCT) and measurements of backscattered light. Any local anomaly of the tissue causes a change of the absorption- and scattering cross sections. In OCT the different layers of the tissue are inspected and anomalies show up as a change in the interference pattern. There are three different techniques of tomography [1549]  

Optical Tomography can inspect layers of tissue up to penefration depths of some centimeters and provides three-dimensional pictures with a spatial resolution of a few micrometers. The axial resolution depends on the spectral width AX of the incident radiation while the transversal resolution is limited by the aperture of the optical imaging system. The axial resolution is 

A practical design uses optical fibers with a fiber beam splitter (Figs. 10.55b and 10.56), which can be used for inspections of stomach cancer because the fiber can be readily inserted into the stomach and layers of the stomach wall can be detected, that are not accessible to classical gastroscopy [1551, 1552]. Examples for further medical applications are the localization of brain tumors, mamma carcinomas or the visualization of the layer structure of the retina (Fig. 10.53). 

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