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Journal of Biomedical Optics • Open Access

Angular domain transillumination imaging optimization with an ultrafast gated camera

Paper Abstract

By employing high-aspect-ratio parallel microchannels as an angular filter, quasiballistic photons sensitive to internal structures in a turbid medium can be captured. Scattered photons exiting the turbid medium typically exhibit trajectories with random angles compared to the initial trajectory and are mostly rejected by the filter. However, angular filter arrays cannot differentiate between quasiballistic photons (early arriving) and photons that happen to attain a scattered trajectory that is within the acceptance angle (late arriving). Therefore, we have two objectives: (1) to experimentally characterize the angular distribution and proportion of minimally deviated quasiballistic photons and multiply scattered photons in a turbid medium and (2) to combine time and angular gating principles so that early and late arriving photons can be distinguished. From the angular distribution data, the angular filter with angular acceptance about 0.4 deg yields the highest image contrast for transillumination images. The use of angular domain imaging(ADI) with time-gating enables visualization of submillimeter absorbing objects with approximately seven times higher image contrast compared to ADI in a turbid medium with a scattering level of six times the reduced mean free path.

Paper Details

Date Published: 1 November 2010
PDF: 12 pages
J. Biomed. Opt. 15(6) 061710 doi: 10.1117/1.3505020
Published in: Journal of Biomedical Optics Volume 15, Issue 6
Show Author Affiliations
Fartash Vasefi, Simon Fraser Univ. (Canada)
Mohamadreza Najiminaini, Simon Fraser Univ. (Canada)
Eldon Ng, The Univ. of Western Ontario (Canada)
Bozena Kaminska, Simon Fraser Univ. (Canada)
Glenn H. Chapman, Simon Fraser Univ. (Canada)
Jeffrey J. L. Carson, Lawson Health Research Institute (Canada)

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