Technology

Bioptigen imaging systems are based on the technology of Optical Coherence Tomography (OCT). OCT is analogous to ultrasound, but uses light waves instead of sound waves. Light backscattered from within a sample is processed to develop a high-resolution, depth-resolved image suitable for analyzing internal microstructure, in vivo, without physical contact. With appropriate lateral scanning, two-dimensional and three-dimensional images with resolution better than 10 micrometers are acquired rapidly and non-invasively. Figure 1: Principles of Optical Coherence Tomography The longitudinal profiling capability of OCT is based on the science of low coherence interferometry. In low coherence interferometry, wide bandwidth light is split and sent along two paths. Light that is reflected or backscattered from a subject sample along one path combines, or interferes, with light reflected from a known reference along another path. This interference signal is collected on a photodetector; the signal strength is directly related to light absorption and scattering properties of the sample precisely at the point where path lengths to the sample and to the reference are matched. The axial (depth) resolution depends critically on the bandwidth of the source light. Very fine depth discrimination requires a specialized wide-bandwidth source.