Optical coherence tomography (OCT) is now an established technique for visualizing the internal morphology of the eye. In the last decade, the aim has been to achieve similar results in highly scattering tissues. One limitation of previous studies with OCT has been the low resolution compared to the gold standard of histology. Full-field optical coherence tomography (FFOCT), a variant of OCT also based on low-coherence interferometry, generates micron-scale images over a large field of view by simply using a camera as an array detector and a tungsten-halogen light source. In this work, a compact FFOCT system has been tested under clinical conditions for imaging breast lesions up to 1 cm² as well as core-needle biopsies. A set of diagnostic criteria have been identified to differentiate benign from malignant tissues with encouraging preliminary results, nonetheless endogenous contrast enhancements are necessary. Attenuation maps were shown to be limited by the high heterogeneity of tissues within only a few micron depth. An alternative approach, based on the elastic properties of tissues, has been demonstrated to be feasible and could hold greater prospects. In addition, the penetration depth of the instrument has been improved by a minimum of a factor two with an InGaAs camera system operating in the infrared region and using silicone oil as immersion medium. Finally, three-dimensional imaging in-vivo was demonstrated during the 4 days of metamorphosis of a Drosophila melanogaster. The FFOCT system was able to record each organ growth at a depth of 80 µm with an isotropic micron resolution. This marks progress towards potential applications in developmental biology.
Advances of full-field optical coherence tomography (FFOCT) for clinical applications and developmental biology