Optical Imaging  

Research Directions


We develop novel biophotonic tomography for early-cancer detection and functional imaging, using non-ionizing electromagnetic and ultrasonic waves. Unlike ionizing x-ray radiation, non-ionizing electromagnetic waves, such as optical and radio waves, pose no health hazard and, at the same time, reveal new contrast mechanisms. For example, our spectroscopic oblique-incidence reflectometry can accurately detect skin cancers, based on their functional hemoglobin parameters and cell nuclear size. Unfortunately, electromagnetic waves in the non-ionizing spectral region do not penetrate biological tissue in straight paths as x-rays do. Consequently, high-resolution tomography that is based on non-ionizing electromagnetic waves alone, as demonstrated by confocal microscopy and two-photon microscopy as well as optical coherence tomography, is limited to superficial imaging within about one optical transport mean free path (~1 mm) of the surface of biological tissue. Ultrasonic imaging, by comparison, provides good image resolution but has strong speckle artifacts as well as poor contrast in early-stage tumors. We have developed ultrasound-mediated imaging modalities by combining electromagnetic and ultrasonic waves synergistically to overcome the above problems. The hybrid modalities yield speckle-free images with high electromagnetic contrast at high ultrasonic resolution in relatively large volumes of biological tissue. Please visit the Research pages to see the specific technologies that we develop.


Last updated 2010.
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Optical Imaging Laboratory at Washington University in St. Louis.