A Noninvasive Optical Topography Measurement System

Abstract

The developed system noninvasively measures topographic images inside tissue by using near-infrared light. Nine incident and four detecting optical fibers are arranged alternately at square lattice points on the subject. Incident light is optically demultiplexed and connected to one of the incident fibers. Light reflected from the subject is received by the detecting fibers, each of which is connected to a photo-diode. The photo-diode outputs are multiplexed. Sixteen combinations of neighboring incident- and detecting-fibers are selected sequentially. Evaluation of system performance by using a phantom containing an absorber localized in a scattering medium showed that this system can topographically detect brain activity in the cerebral cortex.