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1 May 1991 Detection and localization of absorbers in scattering media using frequency-domain principles
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Proceedings Volume 1431, Time-Resolved Spectroscopy and Imaging of Tissues; (1991)
Event: Optics, Electro-Optics, and Laser Applications in Science and Engineering, 1991, Los Angeles, CA, United States
We report on time-resolved reflectance imaging experiments on a scattering medium containing a spatially limited absorber. The medium is illuminated at two positions with pulses from a mode-locked and cavity dumped picosecond dye laser. Time-resolved imaging of the back-scattered light is realized by means of a RF-phase-sensitive camera, synchronized to the laser pulses. The camera consists of a sinusoidally modulated proximity-focused image intensifier, a thermo-electrically cooled CCD camera, and a digital image processor unit. In operation, at least two images are taken under different image intensifier modulation conditions, such as modulation phase or modulation degree. By processing the stored images, a final image can be created the contrast of which is based only on time differences of the back-scattered photons. We found that this image reveals the presence and, to a certain extent, the position of a spatially limited absorber within the scattering medium. These experiments have been performed to evaluate possible ways towards an eventual optical tomography in living tissue.
© (1991) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Klaus W. Berndt and Joseph R. Lakowicz "Detection and localization of absorbers in scattering media using frequency-domain principles", Proc. SPIE 1431, Time-Resolved Spectroscopy and Imaging of Tissues, (1 May 1991);

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