40 research outputs found
Optical coherence tomography and scanning laser ophthalmoscopy: Approaches to dual-channel retinal tissue imaging
No full textWe report a Talbot bands-based optical coherence tomography (OCT) system capable of producing longitudinal B-scan OCT images and en-face scanning laser ophthalmoscopy (SLO) images of the human retina in-vivo, with various degrees of simultaneity
Optical coherence tomography study regarding the enamel structure before and after debonding
No full textOrthodontic treatments imply the use of different types of adhesives and brackets. However, concerns have been raised regarding the effect of these treatments on the structure of the involved teeth. The debonding process is especially regarded as a concern: due to the use of different pliers tensile and pulling forces the develop on the surface of the tooth. The finishing bur is also a concern. Optical Coherence Tomography (OCT), an emerging technology that performs transverse sections of biological systems has been used in order to obtain a more accurate assessment of enamel quality due to its wide applicability and to its non-invasive properties.OCT, analogous to ultrasound imaging(with the difference that it uses light instead of sound), provides cross-sectional images of the tissue structure on the micron scale, in vivo and in real time. Regarding fixed orthodontic treatments, patients are often subjected in the process to a high risk of enamel decalcification and carious processes. Demineralization usually occurs in the area adjacent to the orthodontic bracket location, where bacterial plaque control is difficult. Therefore, in this study we evaluate using OCT the degree of demineralisation produced in the enamel structure, following the removal of the orthodontic bracket. Also, the amount of adhesive remnants after the removal of the adhesive and the finishing of the dental surface with specific instrumentation is evaluated
Fiberised set-up for retinal imaging of the living eye using low coherence interferometry
No full text
Phantoms for performance assessment of optical coherence tomography systems
No full textIn this paper, we describe the procedures to make epoxy resin and agarose phantoms designed using Mie scattering calculations. The phantoms are constructed to be used in the estimation of point spread function (PSF) of an optical coherence tomography (OCT) and evaluation of optical properties extraction (OPE) algorithm
Dispositif bistable magnéto-optique
No full textIn this paper we present a mixed magneto-optical bistable device, realized to the active cavity of a laser by applying an axial magnetic field, the field being driven electronically by means of a feedback loop.L'article présente un dispositif mixte bistable magnéto-optique, réalisé à l'aide d'une cavité laser active à laquelle est appliqué un champ magnétique axial, le champ étant contrôlé par une boucle de contre-réaction dans le dispositif
Two spectral shaping methods of a broadband fibre source for biomedical OCT imaging
No full textThe authors report two investigation methods into the spectral shaping of an optical broadband source (BBS) to be used in Optical Coherence Tomography (OCT). The BBS spectrum extends from 450 nm to 1750 nm and is selectively used in multiple spectral wavebands. Spectral shaping is performed with: (i) an optical filter unit (a combination of dichroic and bandpass filters at different incident angles) and (ii) a double-pass prism sequence (a cube beam splitter, two equilateral prisms and a metallic mirror) which allow the freedom to select the characteristics of the spectrum (central wavelength, spectral bandwidth). BBS can allow imaging with a depth resolution of 2 μm or better. Such a high depth resolution makes BBS suitable for OCT imaging in embryology, cells culture and eye imaging, investigations which will complement the more traditional fluorescence labelling and confocal imaging
3D images of the retina of the living eye generated using transversal OCT images acquired at different depths
No full text
