Vision approach of calibration methods for radiographic systems

The geometric calibration of radiographic systems cannot be avoided in image reconstruction problems in stereoradiography, X-ray or SPECT tomography. This operation performed usually before the object examination, provides the relative positions of the different parts of the system (object, source, detector). The source-detector geometry is then described by intrinsic parameters, and the scanning motion by extrinsic ones

Détection de défauts par utilisation du modèle CAO en multiradiographie

Nous présentons ici les travaux effectués au LETI dans le cadre du projet RADICAD, dont la principale innovation est l'utilisation du modèle CAO de la pièce mécanique inspectée comme information a priori. Trois tâches sont successivement présentées : la simulation de radiographies réalistes de la pièce à partir de son modèle CAO, de la géométrie du banc d'acquisition, des modèles de la source et du détecteur ; la mise en correspondance des simulations et des radiographies afin d'obtenir la position exacte de l'objet pour détecter les défauts par comparaison ; la reconstruction des défauts par un module de reconstruction algébrique limité à des zones d'intérêt. Des résultats obtenus sur données réelles acquises sur un banc de tomographie illustrent l'article

Drug development in oncology assisted by noninvasive optical imaging.

International audienceEarly and accurate detection of tumors, like the development of targeted treatments, is a major field of research in oncology. The generation of specific vectors, capable of transporting a drug or a contrast agent to the primary tumor site as well as to the remote (micro-) metastasis would be an asset for early diagnosis and cancer therapy. Our goal was to develop new treatments based on the use of tumor-targeted delivery of large biomolecules (DNA, siRNA, peptides, or nanoparticles), able to induce apoptosis while dodging the specific mechanisms developed by tumor cells to resist this programmed cell death. Nonetheless, the insufficient effectiveness of the vectorization systems is still a crucial issue. In this context, we generated new targeting vectors for drug and biomolecules delivery and developed several optical imaging systems for the follow-up and evaluation of these vectorization systems in live mice. Based on our recent work, we present a brief overview of how noninvasive optical imaging in small animals can accelerate the development of targeted therapeutics in oncology

VAMP4 directs synaptic vesicles to a pool that selectively maintains asynchronous neurotransmission

Synaptic vesicles in the brain harbor several soluble N-ethylmaleimide-sensitive-factor attachment protein receptor (SNARE) proteins. With the exception of synaptobrevin2, or VAMP2 (syb2), which is directly involved in vesicle fusion, the role of these SNAREs in neurotransmission is unclear. Here we show that in mice syb2 drives rapid Ca2+-dependent synchronous neurotransmission, whereas the structurally homologous SNARE protein VAMP4 selectively maintains bulk Ca2+-dependent asynchronous release. At inhibitory nerve terminals, up- or downregulation of VAMP4 causes a correlated change in asynchronous release. Biochemically, VAMP4 forms a stable complex with SNAREs syntaxin-1 and SNAP-25 that does not interact with complexins or synaptotagmin-1, proteins essential for synchronous neurotransmission. Optical imaging of individual synapses indicates that trafficking of VAMP4 and syb2 show minimal overlap. Taken together, these findings suggest that VAMP4 and syb2 diverge functionally, traffic independently and support distinct forms of neurotransmission. These results provide molecular insight into how synapses diversify their release properties by taking advantage of distinct synaptic vesicle–associated SNAREs

Efficacy and Safety of Ixekizumab in the Treatment of Radiographic Axial Spondyloarthritis:Sixteen-Week Results From a Phase III Randomized, Double-Blind, Placebo-Controlled Trial in Patients With Prior Inadequate Response to or Intolerance of Tumor Necrosis Factor Inhibitors

Objective: To investigate the efficacy and safety of ixekizumab in patients with active radiographic axial spondyloarthritis (SpA) and prior inadequate response to or intolerance of 1 or 2 tumor necrosis factor inhibitors (TNFi). Methods: In this phase III randomized, double-blind, placebo-controlled trial, adult patients with an inadequate response to or intolerance of 1 or 2 TNFi and an established diagnosis of axial SpA (according to the Assessment of SpondyloArthritis international Society [ASAS] criteria for radiographic axial SpA, with radiographic sacroiliitis defined according to the modified New York criteria and ≥1 feature of SpA) were recruited and randomized 1:1:1 to receive placebo or 80-mg subcutaneous ixekizumab every 2 weeks (IXEQ2W) or 4 weeks (IXEQ4W), with an 80-mg or 160-mg starting dose. The primary end point was 40% improvement in disease activity according to the ASAS criteria (ASAS40) at week 16. Secondary outcomes and safety were also assessed. Results: A total of 316 patients were randomized to receive placebo (n = 104), IXEQ2W (n = 98), or IXEQ4W (n = 114). At week 16, significantly higher proportions of IXEQ2W patients (n = 30 [30.6%]; P = 0.003) or IXEQ4W patients (n = 29 [25.4%]; P = 0.017) had achieved an ASAS40 response versus the placebo group (n = 13 [12.5%]), with statistically significant differences reported as early as week 1 with ixekizumab treatment. Statistically significant improvements in disease activity, function, quality of life, and spinal magnetic resonance imaging–evident inflammation were observed after 16 weeks of ixekizumab treatment versus placebo. Treatment-emergent adverse events (AEs) with ixekizumab treatment were more frequent than with placebo. Serious AEs were similar across treatment arms. One death was reported (IXEQ2W group). Conclusion: Ixekizumab treatment for 16 weeks in patients with active radiographic axial SpA and previous inadequate response to or intolerance of 1 or 2 TNFi yields rapid and significant improvements in the signs and symptoms of radiographic axial SpA versus placebo

Feasibility of parathyroid gland autofluorescence imaging after indocyanine green fluorescence angiography

BackgroundIn thyroid surgery, autofluorescence allows the parathyroid glands (PTGs) to be located very early to protect them. Moreover, indocyanine green (ICG) fluorescence angiography (ICG-FA) allows for assessing the viability of the PTGs and identifying blood vessels to preserve them. The main limitation of using ICG-FA is that once ICG has been injected, it is no longer possible to observe PTG autofluorescence using existing devices. This study aimed to describe an approach that allows for visualization of the PTGs by autofluorescence, even after ICG injection.MethodsWe redesigned the FLUOBEAM® LX system to excite fluorescence at 685 nm and detect fluorescence between 700 and 900 nm. This device had short-pass filters at 775 nm that helped to split the contributions of the PTG autofluorescence and ICG fluorescence. Tests were performed on extemporaneous PTG preparations placed next to ICG droplets to assess for rejection of the ICG signal.ResultsA low-pass filter at 775 nm detected 60% of the autofluorescence signals and 10% of the ICG signals.ConclusionThese findings support the possibility of visualizing PTG autofluorescence despite multiple ICG injections and measuring the balance between ICG and autofluorescence signals

"Vision" approach of calibration methods for radiographic systems

The geometric calibration of radiographic systems cannot be avoided in image reconstruction problems in stereoradiography, X-ray or SPECT tomography. This operation performed usually before the object examination, provides the relative positions of the different parts of the system (object, source, detector). The source-detector geometry is then described by intrinsic parameters, and the scanning motion by extrinsic ones.</p

直結腸癌細胞線粒體超微結構與細胞凋亡的關系.

Non destructive testing (NDT) has been widely developed in numerous industrial fields. All the classical techniques - ultrasonics, eddy currents, radiography- are nowadays currently used either for production tests or for facility inspection

CEA Program for Multiple-Technique Non Destructive Testing: The CIVASystem

Non destructive testing (NDT) has been widely developed in numerous industrial fields. All the classical techniques - ultrasonics, eddy currents, radiography- are nowadays currently used either for production tests or for facility inspection.</p

Development of an Advanced 3D Cone Beam Tomographic System

While 2D x-ray CT is now commonly used for NDT applications, the interest in 3D x-ray cone beam tomography has significantly increased over the last few years [1,2]. The need to reduce acquisition time for industrial applications, or radiation dose to patients for medical applications, led engineers to develop a new type of tomograph using x-ray beams more efficiently. Thanks to a high spatial resolution, the 3D x-ray CT allows greater knowledge of the object structure. This understanding is necessary to study and improve industrial production of high technology materials. Therefore, 3D x-ray CT is well suited for the study of materials with structural anomalies, such as technical ceramics [2].</p