4 research outputs found
Plug-in for visualizing 3D tool tracking from videos of Minimally Invasive Surgeries
This paper tackles instrument tracking and 3D visualization challenges in
minimally invasive surgery (MIS), crucial for computer-assisted interventions.
Conventional and robot-assisted MIS encounter issues with limited 2D camera
projections and minimal hardware integration. The objective is to track and
visualize the entire surgical instrument, including shaft and metallic clasper,
enabling safe navigation within the surgical environment. The proposed method
involves 2D tracking based on segmentation maps, facilitating creation of
labeled dataset without extensive ground-truth knowledge. Geometric changes in
2D intervals express motion, and kinematics based algorithms process results
into 3D tracking information. Synthesized and experimental results in 2D and 3D
motion estimates demonstrate negligible errors, validating the method for
labeling and motion tracking of instruments in MIS videos. The conclusion
underscores the proposed 2D segmentation technique's simplicity and
computational efficiency, emphasizing its potential as direct plug-in for 3D
visualization in instrument tracking and MIS practices
A System for 3D Ultrasound-Guided Robotic Retrieval of Foreign Bodies from a Beating Heart
Abstract²By way of the venous system or direct penetration, particles such as thrombi, bullet fragments, and shrapnel can become trapped in the heart and disrupt cardiac function. The severity of disruption can range from asymptomatic to fatal. Injuries of this nature are common in both civilian and military populations. For symptomatic cases, the conventional approach is removal of the foreign body through open heart surgery, which comes with high perioperative risks and a long recovery period. To circumvent these disadvantages, we propose a minimally invasive surgical approach for retrieving foreign bodies from a beating heart. This paper describes the first use of 3D transesophageal echocardiography (TEE) for steering a robot. Experiments demonstrate the feasibility of using 3D ultrasound to both guide and track a robot as it pursues a foreign body, with an RMS error of 1.6 mm in a laboratory setup. Results also support the hypothesis that direct pursuit of the foreign body may exceed the capabilities of conventional surgical robots, necessitating alternate retrieval strategies
Reconstruction 3D de la forme d'aiguilles chirurgicales en utilisant la réflectométrie fréquentielle dans des fibres optiques
L’objectif principal de ce projet de recherche est d’effectuer de la reconstruction de forme
d’aiguilles chirurgicales en insérant des fibres optiques à l’intérieur. En mesurant les contraintes
le long des fibres optiques, on peut facilement obtenir la courbure des fibres. Trois fibres sont
donc utilisées, collées dans une géométrie triangulaire de manière à ce que la différence entre leur
courbure fournisse l’information nécessaire, avec une résolution plus élevée, pour orienter cette
courbure dans un espace tridimensionnel. Puisque la méthode utilisée se base uniquement sur
l’utilisation de fibres optiques, on peut extrapoler les possibles applications à des cathéters, des
côlonoscopes, ou n’importe quels instruments chirurgicaux minimalement invasifs dont la
position dans le corps est importante à connaitre pour maximiser les chances de succès de
l’intervention chirurgicale ou éviter des perforations à l’intérieur du corps.
Jusqu’à présent, l’approche la plus répandue pour ce genre d’applications est l’utilisation de
réseaux de Bragg (« fibre Bragg grating » : FBG) pour mesurer la tension dans la fibre. La
meilleure précision recensée dans la littérature avec cette approche est d’environ 0.28mm, qui
correspond à l’erreur moyenne de la position du bout de l’aiguille. Pour obtenir cette précision,
deux senseurs sont utilisés et chaque senseur comporte trois réseaux de Bragg, soit un dans
chacune des trois fibres utilisées (donc un total de six FBGs). Plusieurs études ont été effectuées
sur des dispositifs semblables, comportant plus ou moins de FBGs séparés de distances
différentes. La plupart de ces études recensent des précisions sur la reconstruction de forme de
l’ordre de quelques millimètres. Cela étant dit, cette approche pour mesurer la tension dans les
fibres est discrète ; l’information sur la tension est donc obtenue uniquement aux endroits où les
réseaux de Bragg sont inscrits et des approximations sont nécessaires pour reconstruire la forme
complète de l’aiguille.
Ce projet de recherche suggère donc l’utilisation d’une approche sensorielle peu Ă©tudiĂ©e jusqu’Ă
présent pour ce type d’applications. Cette approche, contrairement aux FBGs, est pleinement
distribuée. Notre hypothèse de départ est donc qu’en effectuant des mesures de contraintes de
manières distribuées, une meilleure précision peut être obtenue sur la reconstruction de la forme
d’instruments chirurgicaux minimalement invasifs puisqu’elle n’implique plus l’utilisation
d’approximations.----------Abstract The main objective of the research project is to track the shape of minimally invasive surgical
tools (mainly needles) by inserting optical fibers into them. By measuring the strain along the
fibers, we can easily relate it to the curvature of the fibers. Using three fibers glued together in a
triangular geometry, the difference in the measured curvature of each fiber allows one to orientate
the curvature in a 3D frame. Since the approach for shape tracking is strictly based on the
insertion of optical fibers inside the restricted space available in minimally invasive surgical
tools, it can be used with many types of surgical tools such as catheter needles, colonoscopes, or
any other remotely controlled instrument. The knowledge of the position of the device inside the
human body is of paramount importance to maximise the success of the intervention.
Up to now, the most studied approach for shape tracking using optical fibers is based on fiber
Bragg gratings (FBGs), which are useful devices to measure the strain in fibers. To the best of
our knowledge, the best precision reached in the literature based on FBGs is ~0.28mm,
corresponding to the accuracy in the predicted needle tip position. To reach this precision, two
sensors were used, each one containing a set of three fibres with 3 FBGs (one in each fiber) for a
total of 6 FBGs. More studies have been made using similar devices, with more or less number of
FBG sensors separated by different distances. Most of these studies achieve an accuracy in the
order of few millimeters. However, this approach to measure strain along the fibers is completely
discrete since the strain is only known at the positions where the FBGs are located.
Approximations are thus necessary to extrapolate the strains to recover the whole shape of the
needle.
This project suggests a truly distributed approach, different to the discrete FBGs technique,
which has received little attention up to now for this type of applications. Our first hypothesis is
that the precision of the shape tracking can be enhanced by using truly distributed strain sensing
(instead of discrete sensing) since approximations are not needed to obtain the shape of the entire
needle.
This approach is based on optical frequency domain reflectometry (OFDR), which is an
interferometric method frequently used to measure the attenuation along fibers. Indeed, OFDR is
based on Rayleigh scattering, which is caused by a random distribution of refractive index on a
microscopic scale in the fiber core