Abstract

Quantitative depth of tumor invasion in early gastric cancer cases via the scattering of circularly polarized light was computationally and experimentally estimated. Invasion depth information of cancer in early stages, which is difficult to obtain accurately using current biological imaging technologies, is very beneficial for cancer diagnosis. The circularly polarized light scattering method, proposed as a novel biomedical evaluation technique, can provide depth profiles by varying the incident or detection angles as well as wavelengths of circularly polarized light. Incident circularly polarized light is gradually depolarized owing to multiple scattering against cell nuclei in biological tissues. Since the degree of depolarization significantly depends on the size and shape of the scattering particles, the enlargement of cell nuclei in the scattering volume due to cancerization can be investigated by assaying the polarization of scattered light. This paper reports the results of Monte Carlo simulations and experiments to demonstrate cancer depth estimation using this technique. The Monte Carlo simulation for bilayered pseudo-tissues with a cancerous layer on a healthy layer indicates that the degree of circular polarization of scattered light shows systematic changes depending on the thickness and depth of cancerous tissues. Additionally experiments with bilayered biological tissues exhibits the same tendency as the simulation results.

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