1. Articles from a. bradu

    1-11 of 11
    1. Multispectral photoacoustic microscopy and optical coherence tomography using a single supercontinuum source

      Multispectral photoacoustic microscopy and optical coherence tomography using a single supercontinuum source

      We report on the use of a single supercontinuum (SC) source for multimodal imaging. The 2-octave bandwidth (475–2300 nm) makes the SC source suitable for optical coherence tomography (OCT) as well as for multispectral photoacoustic microscopy (MPAM). The IR band centered at 1310 nm is chosen for OCT to penetrate deeper into tissue with 8 mW average power on the sample. The 500–840 nm band is used for MPAM. The source has the ability to select the central wavelength as well as the spectral bandwidth. An energy of more than 35 nJ within a less than 50 nm ...

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    2. OCT and shear-force evaluations of zirconia Fixed Partial Prosthesis processed with a conventional CAD/CAM technology

      OCT and shear-force evaluations of zirconia Fixed Partial Prosthesis processed with a conventional CAD/CAM technology

      Introduction. Dental ceramics show better biocompatibility and aesthetic properties in dental constructs with regard to metals. However, they also have an insufficient mechanical stability, as well as low resistance limits due to their fragility. Taking into account these aspects, glass infiltrated with ceramic materials such as alumina (i.e., zirconiareinforced ceramics) is being nowadays considered a better material for full fixed partial prostheses (FPPs) than ceramics: the former has a higher mechanical resistance, which makes it more appropriate for restoration areas, where there is an increased mechanical stress. The interest for zirconia is growing due both to its resistance and ...

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    3. OCT evaluation of single ceramic crowns: comparison between conventional and chair-side CAD/CAM technologies

      OCT evaluation of single ceramic crowns: comparison between conventional and chair-side CAD/CAM technologies

      Digital impressions were introduced to overcome some of the obstacles due to traditional impression materials and techniques. The aim of this in vitro study is to compare the accuracy of all ceramic crowns obtained with digital impression and CAD-CAM technology with the accuracy of those obtained with conventional impression techniques. Two groups of 10 crowns each have been considered. The digital data obtained from Group 1 have been processed and the all-ceramic crowns were milled with a CAD/CAM technology (CEREC MCX, Sirona). The all ceramic crowns in Group 2 were obtained with the classical technique of pressing (emax, Ivoclar ...

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    4. Handheld scanning probes for optical coherence tomography: developments, applications, and perspectives

      Handheld scanning probes for optical coherence tomography: developments, applications, and perspectives

      We present the handheld scanning probes that we have recently developed in our current project for biomedical imaging in general and for Optical Coherence Tomography (OCT) in particular. OCT is an established, but dynamic imagistic technique based on laser interferometry, which offers micrometer resolutions and millimeters penetration depths. With regard to existing devices, the newly developed handheld probes are simple, light and relatively low cost. Their design is described in detail to allow for the reproduction in any lab, including for educational purposes. Two probes are constructed almost entirely from off-the-shelf components, while a third, final variant is constructed with ...

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    5. Broadband master-slave interferometry using a super-continuum source

      Broadband master-slave interferometry using a super-continuum source

      In this report we applied the principle of Master-Slave Interferometry (MSI) to an Optical Coherence Tomography (OCT) employing a Super-Continuum (SC) light source. A-scans and B-scan images of biological and non-biological sample are presented in order to demonstrate similar performance with the images obtained with the resampled Fourier Transform (FT) based OCT technique. Dispersion tolerance of MSI method is demonstrated as a constant axial resolution over the depth range even though dispersion is left uncompenstaed in the system.

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    6. Feature Of The Week 10/5/14: Design and Testing of Handheld Scanning Probe Prototypes for Optical Coherence Tomography

      Feature Of The Week 10/5/14: Design and Testing of Handheld Scanning Probe Prototypes for Optical Coherence Tomography

      Three simple and low-cost configurations of handheld scanning probes for optical coherence tomography have been developed. Their design and testing for dentistry applications are presented. The first two configurations were built exclusively from available off-the-shelf optomechanical components, which, to the best of our knowledge, are the first designs of this type. The third configuration includes these components in an optimized and ergonomic probe. All the designs are presented in detail to allow for their duplication in any laboratory with a minimum effort, for applications that range from educational to high-end clinical investigations. Requirements that have to be fulfilled to achieve ...

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    7. Evaluation of metal-polymeric fixed partial prosthesis using optical coherence tomography

      Evaluation of metal-polymeric fixed partial prosthesis using optical coherence tomography

      Metal-Polymeric fixed partial prosthesis is the usual prosthetic treatment for many dental patients. However, during the mastication the polymeric component of the prosthesis is fractured and will be lost. This fracture is caused by the material defects or by the fracture lines trapped inside the esthetic components of the prosthesis. This will finally lead to the failure of the prosthetic treatment. Nowadays, there is no method of identification and forecast for the materials defects of the polymeric materials. The aim of this paper is to demonstrate the capability of Optical Coherence Tomography (OCT) as a non-invasive clinical method that can ...

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    8. Optimization of Excitation of Fiber Fabry-Perot Tunable Filters Used In Swept Sources for Optical Coherence Tomography Using Simulated Annealing Algorithm

      Optimization of Excitation of Fiber Fabry-Perot Tunable Filters Used In Swept Sources for Optical Coherence Tomography Using Simulated Annealing Algorithm

      We investigate the improvement in the nonlinearity of a conventional wavelength swept laser source based on a fiber Fabry-Perot tunable filter using a well established optimization method, simulated annealing (SA). The signal driving the filter is constructed from many short ramps of different slopes that are connected to each other. The values of the slopes are optimised using the SA algorithm in order to achieve maximum amplitude for the Fourier transformed peaks of the photodetected interferometric signal.

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    9. Ex vivo optical coherence tomography imaging of larynx tissues using a forward-viewing resonant fiber-optic scanning endoscope

      Ex vivo optical coherence tomography imaging of larynx tissues using a forward-viewing resonant fiber-optic scanning endoscope

      A miniature endoscope probe for forward viewing in a 50 kHz swept source optical coherence tomography (SS-OCT) configuration was developed. The work presented here is an intermediate step in our research towards in vivo endoscopic laryngeal cancer screening. The endoscope probe consists of a miniature tubular lead zirconate titanate (PZT) actuator, a single mode fiber (SMF) cantilever and a GRIN lens, with a diameter of 2.4 mm. The outer surface of the PZT actuator is divided into four quadrants that form two pairs of orthogonal electrodes (X and Y). When sinusoidal waves of opposite polarities are applied to one ...

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    10. Dual excitation waveform Fabry-Perot tunable filters used in swept sources

      Dual excitation waveform Fabry-Perot tunable filters used in swept sources
      We report experimental evidence of a novel method to quench the resonances of a Fabry-Perot tunable filter typically used as a wavelength selective element in swept source OCT systems. The method is based on applying a non-sinusoidal, synthesized waveform to the tunable filter, waveform that can be found experimentally in a few iteration steps. A significant improvement in the OCT image quality has been obtained without any software recalibration method.
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    11. Combining confocal microscopy and optical coherence tomography for imaging in developmental biology

      A. Bradu, Lisha Ma, J. Bloor et al. In-vivo Optical Coherence Tomography (OCT) imaging of the fruit fly Drosophila melanogaster larval heart allows non invasive visualizations and assesment of its cardiac functions. To image Drosophila melanogaster heart, we have developed a dedicated imaging instrument able to provide simultaneous Op ... [Proc. SPIE Int. Soc. Opt. Eng. 6991, 69910K (2008)] published Fri May 2, 2008.
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    1-11 of 11
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  2. Topics in the News

    1. (11 articles) Adrian Bradu
    2. (11 articles) Adrian G. Podoleanu
    3. (10 articles) University of Kent
    4. (5 articles) Virgil-Florin Duma
    5. (5 articles) Cosmin Sinescu
    6. (5 articles) Meda-Lavinia Negrutiu
    7. (4 articles) Victor Babes University of Medicine and Pharmacy
    8. (3 articles) Ramona Cernat
    9. (2 articles) Dorin Demian
    10. (2 articles) Gheorghe Hutiu
    11. (1 articles) Tufts University
    12. (1 articles) UCLA
    13. (1 articles) Universidade Federal de São Paulo
    14. (1 articles) University of Auckland
    15. (1 articles) University of North Carolina
    16. (1 articles) Xuan Liu
    17. (1 articles) Frederique Vanholsbeeck
    18. (1 articles) Yoshiyasu Minami
    19. (1 articles) Amy L. Oldenburg
    20. (1 articles) Carl Zeiss Meditec
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    Dual excitation waveform Fabry-Perot tunable filters used in swept sources Ex vivo optical coherence tomography imaging of larynx tissues using a forward-viewing resonant fiber-optic scanning endoscope Optimization of Excitation of Fiber Fabry-Perot Tunable Filters Used In Swept Sources for Optical Coherence Tomography Using Simulated Annealing Algorithm Evaluation of metal-polymeric fixed partial prosthesis using optical coherence tomography Feature Of The Week 10/5/14: Design and Testing of Handheld Scanning Probe Prototypes for Optical Coherence Tomography Broadband master-slave interferometry using a super-continuum source Handheld scanning probes for optical coherence tomography: developments, applications, and perspectives OCT evaluation of single ceramic crowns: comparison between conventional and chair-side CAD/CAM technologies OCT and shear-force evaluations of zirconia Fixed Partial Prosthesis processed with a conventional CAD/CAM technology Novel Optical Coherence Tomography Parameters as Prognostic Factors for Stage 3 Epiretinal Membranes En-face OCT and OCT angiography analysis of macular choroidal macrovessel Three-dimensional live imaging of bovine embryos by optical coherence tomography