Reducing patient stress during testing while improving the medical instrumentation used to detect cancer during checkups is truly a win-win for all involved. Such was the task facing researchers at Tokyo's Kitasato University's Center for Fundamental Sciences. The key focus of their research was to improve on traditional methods of cancer detection that do not provide sufficient resolution or require the patient to undergo severe stress during the checkup.
　　With that goal in mindwww.cechina.cn, Kitasato's

researchers set out to create a high-speed Fourier domain optical coherence tomography (OCT) system. OCT is a noninvasive imaging technique that provides subsurfacewww.cechina.cn, cross-sectional images of translucent or opaque materials. OCT images enable the visualization of tissues or other objects with resolution similar to that of some microscopes. In the academic communitywww.cechina.cn, there has been an increasing interest in OCT because it provides much greater resolution than other imaging techniques such as magnetic resonance imaging (MRI) or positron emission tomography (PET). Additionally, the method is extremely safe for the patient because of very low laser outputs and no need for ionizing radiation.

　　The 30.3 dB reflection is attenuated with neutral density filters. The thick solid curve is the noise floor measured with the sample light blocked. Sensitivity determined by these values is scaled at the right-hand side vertical scale.

　　OCT uses a low-power light source and the corresponding light reflections to create images—a method similar to ultrasound. The difference is that light is monitored instead of sound. When a beam is projected into a sample, much of the light is scattered, but a small amount reflects as a collimated beamCONTROL ENGINEERING China版权所有, which can be detected and used to create an image.
　　Light into images
　　The Fourier domain OCT system developed by Kitasato's researchers uses optical demultiplexers to enable separation of 256 narrow spectral bands from a broadband incident light in a 2