Fluoroscopie

La fluoroscopie, ou radioscopie, est une modalité de la radiologie qui consiste à acquérir en instantané des images dynamiques de l'intérieur des structures. Historique Initialement, les radioscopies étaient utilisées de la même manière que les radiographies : au lieu d'obtenir un cliché, le médecin observait en direct. Cette démarche a été abandonnée car elle provoquait une exposition inutilement excessive aux rayons X du patient et du médecin. Appareillage vignette|Fluoroscope des années 1950, pour détecter un cancer de l'estomac. Un système de fluoroscopie est constitué d'un générateur de rayons X capable d'émettre des rayons X pendant plusieurs minutes de manière continue ou de manière pulsée. Initialement, l'image se formait sur un écran fluorescent. Sur les appareils modernes, l'image est acquise au moyen d'un amplificateur de brillance ou de certains capteurs plans capables de fonctionner en acquisition continue. Les images sont rapatriées en instan

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Standardization proposal of soft tissue artefact description for data sharing in human motion measurements

Kamiar Aminian, Arnaud Barré

Soft tissue artefact (STA) represents one of the main obstacles for obtaining accurate and reliable skeletal kinematics from motion capture. Many studies have addressed this issue, yet there is no consensus on the best available bone pose estimator and the expected errors associated with relevant results. Furthermore, results obtained by different authors are difficult to compare due to the high variability and specificity of the phenomenon and the different metrics used to represent these data. Therefore, the aim of this study was twofold: firstly, to propose standards for description of STA; and secondly, to provide illustrative STA data samples for body segments in the upper and lower extremities and for a range of motor tasks specifically, level walking, stair ascent, sit-to-stand, hip- and knee-joint functional movements, cutting motion, running, hopping, arm elevation and functional upper-limb movements. The STA dataset includes motion of the skin markers measured in vivo and ex vivo using stereophotogrammetry as well as motion of the underlying bones measured using invasive or bio-imaging techniques (i.e., X-ray fluoroscopy or MRI). The data are accompanied by a detailed description of the methods used for their acquisition, with information given about their quality as well as characterization of the STA using the proposed standards. The availability of open-access and standard-format STA data will be useful for the evaluation and development of bone pose estimators thus contributing to the advancement of three-dimensional human movement analysis and its translation into the clinical practice and other applications.

Elsevier2017

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Evaluation of knee functional calibration with and without the effect of soft tissue artefact

Kamiar Aminian, Arnaud Barré

Functional calibration methods were devised to improve repeatability and accuracy of the knee flexion-extension axis, which is used to define the medio-lateral axis of the femur coordinate system in gait analysis. Repeatability of functional calibration methods has been studied extensively in healthy individuals, but not accuracy in the absence of a benchmark knee axis. We captured bi-plane fluoroscopy data of the knee joint in 17 subjects with unilateral total knee arthroplasty during treadmill walking. The prosthesis provided a benchmark knee axis to evaluate the functional calibration methods. Stereo-photogrammetry data of thigh and shank marker clusters were captured simultaneously to investigate the effect of soft tissue artefact (STA). Three methods were tested, the Axis Transformation Technique (ATT) finds the best single fixed axis of rotation, 2DofKnee finds the axis that minimises knee varus-valgus and trajAJC finds the axis perpendicular to the trajectory, in the transverse plane of the femur, of a point located on the longitudinal axis of the tibia. Using fluoroscopy data, functional axes formed an angle of less than 2° in the transverse plane with the benchmark axis. True internal-external range of movement was correlated with decreased accuracy for ATT, while varus-valgus range of movement was correlated with decreased accuracy for 2DofKnee and trajAJC. STA had negative impact on accuracy and variability. Using stereo-photogrammetry data, the accuracy of 2DofKnee was 1.7°(SD: 5.1°), smaller than ATT 2.9°(SD: 5.1°) but not to trajAJC 1.7°(SD: 5.2°). Our results confirm that of previous studies, which utilised the femur condylar axis as reference.

Elsevier2017

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Locomotion of Sensor‐Integrated Soft Robotic Devices Inside Sub‐Millimeter Arteries with Impaired Flow Conditions

Amit Yedidia Dolev, Adele Fanelli, Diego Ghezzi, Lorenzo Francesco John Noseda, Mahmut Selman Sakar

One of the grand challenges in interventional cardiology and neuroradiology is to minimize the operation time and risk of damage during catheterization. These two factors drastically increase if the target location resides in small and tortuous vessels. Flow-driven microcatheters are capable of rapidly and safely navigating small arteries with complex anatomy. However, their navigation relies on proper perfusion, which is an important bottleneck in the treatment of pathologies that cause impaired flow conditions. This work introduces the first endovascular sensor-integrated soft robotic device that navigates sub-millimeter arteries by extracting propulsive power from external magnetic fields. To this end, a number of innovations are described in the design, actuation, and control of flexible magnetic structures. The device is capable of advancing inside vasculature in an automated fashion using an open-loop control scheme. Onboard sensors enable the real-time monitoring of flow conditions, and autonomous switching between different modes of locomotion. The potential of the presented technology for minimally invasive diagnosis and therapy is demonstrated by achieving navigation inside coronary arteries of an ex vivo porcine heart under fluoroscopic guidance.

Wiley2022

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Rayon X

Radiographie

vignette|droite|redresse=1.2|Radiographie pulmonaire numérisée. La radiographie est une technique d', par rayons X dans le cadre de la radiographie X, ou par rayons gamma en gammagraphie. Les

Radiologie médicale

vignette|right|Radiographie montrant une fracture distale de l'avant bras. thumb| Macintyre's X-Ray Film (1896) La radiologie dans le domaine médical, désigne l'ensemble des modalités diagnostiques e

PHYS-455: Introduction to medical radiation physics

This course covers the physical principles underlying medical diagnostic imaging (radiography, fluoroscopy, CT, SPECT, PET, MRI), radiation therapy and radiopharmacy. The focus is not only on risk and dose to the patient and staff, but also on an objective description of the image quality.

PHYS-405: Experimental methods in physics

The course's objectivs are: Learning several advenced methods in experimental physics, and critical reading of experimental papers.

MSE-704: 3D Electron Microscopy and FIB-Nanotomography

The principles of 3D surface (SEM) reconstruction and its limitations will be explained. 3D volume reconstruction and tomography methods by electron microscopy (SEM/FIB and TEM) will be explained and compared with x-ray tomography.