Tissue imaging with optical coherence tomography

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Biophotonics in Australia 2006. Optical coherence tomography. Outline. Optical coherence tomography. • Tissue optics. • Speckle as a carrier of information.

Tissue imaging with optical coherence tomography

David Sampson School of Electrical, Electronic, & Computer Engineering

Outline Optical coherence tomography • Tissue optics • Speckle as a carrier of information • Limits on ultrahigh (1 µm) resolution • Alternative non-scanning holographic approach • Medical imaging - upper airway

Biophotonics in Australia 2006

Optical coherence tomography

Experimental results - microspheres

Hillman et al., Opt. Lett., p.190, 2006 Biophotonics in Australia 2006

Optical coherence tomography

What got everyone in OCT very excited

Ultrahigh resolution in Xenopus Laevis • • • • •

5-fs 800-nm mode-locked Ti:Sapphire laser 1-µm axial and 5-µm transverse Synthesis of images - not real time imaging Strongly confocal - focus set at different depths Dispersion compensated at each depth

Biophotonics in Australia 2006

W. Drexler, U. Morgner, F. X. Kärtner, C. Pitris, S. A. Boppart, X. D. Li, E. P. Ippen, J. G. Fujimoto, In vivo ultrahighresolution optical coherence tomography, Opt. Lett. 24 (1999) 1221-1223

Optical coherence tomography

Effects of absorption and dispersion

Hillman et al., Opt. Express, 2005, p1861 Biophotonics in Australia 2006

Optical coherence tomography

Reconstructed set of images at each angle

500 µm

500 µm Biophotonics in Australia 2006

Optical coherence tomography

Obstructive sleep apnoea “Repetitive collapse of upper airway during sleep” • Common – 4% of population • Massive economic impact: $10B pa in Australia • Common treatments: CPAP, MAD, surgery • Treatments are – empirical – often ineffective or poorly tolerated – not tailored to individuals • Huge market – e.g. RESMED - $700m Australian company supplying CPAP treatment • Increased likelihood of – Stroke – Heart attack – Car accident – ADHD in children Biophotonics in Australia 2006

Optical coherence tomography

Current options are not suitable •

X-ray computed tomography – Ionising radiation, short term because of dose



MRI – Noisy, claustrophobic, short term because of expense



Video endoscopy – Not quantitative

Biophotonics in Australia 2006

Optical coherence tomography

Clinical measurements – Compliance Important physiological parameters such as compliance are measurable

Airway images at different applied pressures. Red - 3 cm H2O Blue - 9 cm H2O Green - 12 cm H2O Biophotonics in Australia 2006

Optical coherence tomography

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