Design of an ultrasound-guided robotic brachytherapy needle insertion system

In this paper we describe a new robotic brachytherapy needle-insertion system that is designed to replace the template used in the manual technique. After a brief review of existing robotic systems, we describe the requirements that we based our design upon. A detailed description of the proposed system follows. Our design is capable of positioning and inclining a needle within the same workspace as the manual template. To help improve accuracy, the needle can be rotated about its axis during insertion into the prostate. The system can be mounted on existing steppers and also easily accommodates existing seed dispensers, such as the Mick Applicator

Prosper: image and robot-guided prostate brachytherapy

Brachytherapy for localized prostate cancer consists in destroying cancer by introducing iodine radioactive seeds into the gland through hollow needles. The planning of the position of the seeds and their introduction into the prostate is based on intra-operative ultrasound (US) imaging. We propose to optimize the global quality of the procedure by: i) using 3D US; ii) enhancing US data with MRI registration; iii) using a specially designed needle-insertion robot, connected to the imaging data. The imaging methods have been successfully tested on patient data while the robot accuracy has been evaluated on a realistic deformable phantom

Using CamiTK for rapid prototyping of interactive Computer Assisted Medical Intervention applications

Computer Assisted Medical Intervention (CAMI hereafter) is a complex multi-disciplinary field. CAMI research requires the collaboration of experts in several fields as diverse as medicine, computer science, mathematics, instrumentation, signal processing, mechanics, modeling, automatics, optics, etc

Design and evaluation of robotic systems for medical image guided percutaneous needle interventions

Cette thèse décrit la conception et l'évaluation de systèmes robotiques de ponctions percutanées d'aiguilles guidés par imagerie médicale. Les ponctions percutanées d'aiguilles sont devenues de plus en plus communs dans la diagnostique et le traitement d'un assortiment de maladies humaines. Des exemples d'interventions fréquentes sont les biopsies, les ablations de tumeurs par radiofréquence, la cryothérapie, le drainage et la curiethérapie, entre autres. Le couplage de l'imagerie médicale avec l'insertion d'une aiguille donne suite à un nombre de difficultés pour le clinicien, tels que l'alignement précis de l'aiguille à la trajectoire planifiée dans l'image, la réalisation de trajectoires complexes et hors-plans difficiles à visualiser, et la compensation du mouvement et déformation des tissus mous. La robotique peut être utilisé pour assister à ces procédures pour simplifier les défis et potentiellement améliorer leur précision, leur bénéfices cliniques et leurs taux d'inclusion. Cette thèse expose les défis techniques et cliniques auxquels il faut faire typiquement face pendant la conception et l'évaluation de tels robots de ponction, tout en restant sur les aspects qui les différentient d'autres robots médicaux. Une revue de l'état de l'art est utilisé pour décrire ces défis et pour présenter les divers solutions déjà proposés pour leur faire face. Sur cette base, deux tels systèmes robotiques, développés pendant cette thèse, sont décrits en détail, donnant ainsi des exemples concrètes des nombreuses contraintes imposés dans le cadre de ponctions d'aiguilles guidés par imagerie médicale. Le premier système, s'appelant PROSPER, est dédié aux interventions prostatiques transpérinéales guidés par imagerie ultrasonique, en particulier la curiethérapie. Le robot est fixé à la table chirurgicale et une sonde échographique 3D transrectale lui est rigidement relié, permettant ainsi un calibrage préopératoire entre l'espace du robot et l'espace image. Le protocole développé pour ce système inclue un recalage écho-écho peropératoire pour compenser le mouvement et la déformation de la prostate pendant l'insertion des aiguilles. Ce chapitre expose les défis d'un système qui n'est pas physiquement présent dans l'espace de l'image et qui tient en compte le divers contraintes intrinsèques à l'environnement des tissus mous. Le deuxième système s'appelle LPR et est destiné à la radiologie interventionnelle des régions thoraciques et abdominopelviennes, sous guidage TDM et IRM. Il est fixé sur le corps du patient et positionne et insère une aiguille selon une trajectoire et visant une cible choisis par le radiologue dans l'image. Le robot est calibré à l'image en peropératoire par moyens de mires multimodales incorporés dans la structure du robot. Il est entièrement compatible avec les deux modalités d'imagerie en terme de qualité d'image et contraintes de taille. Par rapport au robot PROSPER, ce chapitre montre comment la présence du robot dans l'espace de l'image donne suite à un nombre d'autres défis qui doivent être considérés pour permettre son acceptabilité clinique. Dans les descriptions des deux systèmes, l'accent est mis sur les solutions innovantes mises en place dans le but de fournir des vrais bénéfices cliniques aux patients ainsi qu'aux cliniciens. Des prototypes de chaque système ont été développés et évalués sur des fantômes synthétiques en termes de leur précision et compatibilité préclinique.This thesis describes the design and evaluation of robotic systems for medical image guided percutaneous needle interventions. Percutaneous needle interventions have become increasingly more common in the diagnosis and treatment of a variety of illnesses in the human population. Examples include biopsies, radiofrequency ablation, cryotherapy, abscess drainage, and brachytherapy, amongst others. The coupling of medical imaging to the insertion of a needle raises a number of difficulties for the physician, such as accurately aligning the needle to the planned trajectory in the image, realizing complex out-of-plane trajectories that are difficult to visualize and compensating for soft tissue motion. Robotics can be used to assist these procedures and simplify these challenges, potentially resulting in more accurate procedures, better clinical outcomes and greater patient eligibility. This thesis outlines the technical and clinical challenges typically faced during the design and evaluation of such needle insertion robots. Focus is given primarily to the aspects which differentiate needle insertion robots from other medical robots. A review of the state of the art is used to describe these challenges and to present some of the solutions that have been proposed to face them. On this basis, two such robotic systems, developed during this thesis, are described in detail, providing concrete examples of the variety of design constraints imposed in a medical image guided needle insertion setting. The first system, called PROSPER, is for ultrasound(US)-guided transperineal prostate interventions, in particular brachytherapy. It is mounted to the surgical table and a 3D transrectal US probe is rigidly connected to it, allowing one-time pre-operative calibration between the image and the robot coordinate spaces. The protocol developed for this system includes intra-operative US-US registration in order to compensate for prostate motion and deformation during insertion. This chapter exposes the challenges of a system that is not physically present in the imaging space and that takes into account the various constraints inherent to a soft tissue environment. The second system, called the LPR, is for thoracic and abdominopelvic interventional radiology procedures under CT and MRI guidance. It is mounted on the patient's body and positions and inserts the needle according to the trajectory and target chosen by the radiologist in the image. The robot is calibrated to the image intra-operatively using multi-modal fiducials embedded in the robot's structure. It is fully compatible with both imaging modalities in terms of image quality and space constraints. As opposed to the PROSPER robot, this chapter shows how the presence of the robot in the imaging space brings about a number of additional challenges that must be faced for its clinical acceptability. In the descriptions of both systems, emphasis is placed on the novel solutions put into place with the goal of providing a real clinical benefit to both patients and clinicians. Prototypes of each system were developed and evaluated on synthetic phantoms in terms of their pre-clinical compatibility and accuracy

Conception et évaluation de systèmes robotiques de ponction d'aguilles percutanées sous contrôle d'imagerie médicale

This thesis describes the design and evaluation of robotic systems for medical image guided percutaneous needle interventions. Percutaneous needle interventions have become increasingly more common in the diagnosis and treatment of a variety of illnesses in the human population. Examples include biopsies, radiofrequency ablation, cryotherapy, abscess drainage, and brachytherapy, amongst others. The coupling of medical imaging to the insertion of a needle raises a number of difficulties for the physician, such as accurately aligning the needle to the planned trajectory in the image, realizing complex out-of-plane trajectories that are difficult to visualize and compensating for soft tissue motion. Robotics can be used to assist these procedures and simplify these challenges, potentially resulting in more accurate procedures, better clinical outcomes and greater patient eligibility. This thesis outlines the technical and clinical challenges typically faced during the design and evaluation of such needle insertion robots. Focus is given primarily to the aspects which differentiate needle insertion robots from other medical robots. A review of the state of the art is used to describe these challenges and to present some of the solutions that have been proposed to face them. On this basis, two such robotic systems, developed during this thesis, are described in detail, providing concrete examples of the variety of design constraints imposed in a medical image guided needle insertion setting. The first system, called PROSPER, is for ultrasound(US)-guided transperineal prostate interventions, in particular brachytherapy. It is mounted to the surgical table and a 3D transrectal US probe is rigidly connected to it, allowing one-time pre-operative calibration between the image and the robot coordinate spaces. The protocol developed for this system includes intra-operative US-US registration in order to compensate for prostate motion and deformation during insertion. This chapter exposes the challenges of a system that is not physically present in the imaging space and that takes into account the various constraints inherent to a soft tissue environment. The second system, called the LPR, is for thoracic and abdominopelvic interventional radiology procedures under CT and MRI guidance. It is mounted on the patient's body and positions and inserts the needle according to the trajectory and target chosen by the radiologist in the image. The robot is calibrated to the image intra-operatively using multi-modal fiducials embedded in the robot's structure. It is fully compatible with both imaging modalities in terms of image quality and space constraints. As opposed to the PROSPER robot, this chapter shows how the presence of the robot in the imaging space brings about a number of additional challenges that must be faced for its clinical acceptability. In the descriptions of both systems, emphasis is placed on the novel solutions put into place with the goal of providing a real clinical benefit to both patients and clinicians. Prototypes of each system were developed and evaluated on synthetic phantoms in terms of their pre-clinical compatibility and accuracy.Cette thèse décrit la conception et l'évaluation de systèmes robotiques de ponctions percutanées d'aiguilles guidés par imagerie médicale. Les ponctions percutanées d'aiguilles sont devenues de plus en plus communs dans la diagnostique et le traitement d'un assortiment de maladies humaines. Des exemples d'interventions fréquentes sont les biopsies, les ablations de tumeurs par radiofréquence, la cryothérapie, le drainage et la curiethérapie, entre autres. Le couplage de l'imagerie médicale avec l'insertion d'une aiguille donne suite à un nombre de difficultés pour le clinicien, tels que l'alignement précis de l'aiguille à la trajectoire planifiée dans l'image, la réalisation de trajectoires complexes et hors-plans difficiles à visualiser, et la compensation du mouvement et déformation des tissus mous. La robotique peut être utilisé pour assister à ces procédures pour simplifier les défis et potentiellement améliorer leur précision, leur bénéfices cliniques et leurs taux d'inclusion. Cette thèse expose les défis techniques et cliniques auxquels il faut faire typiquement face pendant la conception et l'évaluation de tels robots de ponction, tout en restant sur les aspects qui les différentient d'autres robots médicaux. Une revue de l'état de l'art est utilisé pour décrire ces défis et pour présenter les divers solutions déjà proposés pour leur faire face. Sur cette base, deux tels systèmes robotiques, développés pendant cette thèse, sont décrits en détail, donnant ainsi des exemples concrètes des nombreuses contraintes imposés dans le cadre de ponctions d'aiguilles guidés par imagerie médicale. Le premier système, s'appelant PROSPER, est dédié aux interventions prostatiques transpérinéales guidés par imagerie ultrasonique, en particulier la curiethérapie. Le robot est fixé à la table chirurgicale et une sonde échographique 3D transrectale lui est rigidement relié, permettant ainsi un calibrage préopératoire entre l'espace du robot et l'espace image. Le protocole développé pour ce système inclue un recalage écho-écho peropératoire pour compenser le mouvement et la déformation de la prostate pendant l'insertion des aiguilles. Ce chapitre expose les défis d'un système qui n'est pas physiquement présent dans l'espace de l'image et qui tient en compte le divers contraintes intrinsèques à l'environnement des tissus mous. Le deuxième système s'appelle LPR et est destiné à la radiologie interventionnelle des régions thoraciques et abdominopelviennes, sous guidage TDM et IRM. Il est fixé sur le corps du patient et positionne et insère une aiguille selon une trajectoire et visant une cible choisis par le radiologue dans l'image. Le robot est calibré à l'image en peropératoire par moyens de mires multimodales incorporés dans la structure du robot. Il est entièrement compatible avec les deux modalités d'imagerie en terme de qualité d'image et contraintes de taille. Par rapport au robot PROSPER, ce chapitre montre comment la présence du robot dans l'espace de l'image donne suite à un nombre d'autres défis qui doivent être considérés pour permettre son acceptabilité clinique. Dans les descriptions des deux systèmes, l'accent est mis sur les solutions innovantes mises en place dans le but de fournir des vrais bénéfices cliniques aux patients ainsi qu'aux cliniciens. Des prototypes de chaque système ont été développés et évalués sur des fantômes synthétiques en termes de leur précision et compatibilité préclinique

Haptic emulation of hard surfaces with applications to orthopaedic surgery

A generally accepted goal in orthopaedic surgery today is to maximize conservation of tissue and reduce tissue damage. Bone-conserving implants have bone-mating surfaces that reproduce the natural curvature of bone structures, requiring less bone removal. No small, reliable, inexpensive and universal bone sculpting technique currently exists, however, that can both create and accurately align such complex surfaces. The goal of this thesis was to develop a haptic hard surface emulation mechanism that could be applied to curvilinear bone sculpting using a surgical robot. A novel dynamic physical constraint concept was developed that is able to emulate realistic hard constraints, smooth surface following, and realistic surface rigidity, while allowing complete freedom of motion away from the constraints. The concept was verified through the construction of a two-link manipulator prototype. Tests were run on nine users that involved each user tracing out five different virtual surfaces on a drawing surface using the prototype. The primary purposes of prototype testing were to obtain subjective data on how effectively the dynamic physical constraint concept simulates simple surfaces, to assess how it reacts to typical user interactions and to identify any unexpected behaviour. Users were 100% satisfied with the prototype’s ability to emulate realistic and stiff hard surfaces and with its ease of manipulation. The amount of incursion into each of the virtual surfaces by all the users was measured to assess the precision of the system with the goal of deciding whether this new haptic concept should be further developed specifically for precision applications such as surgery. For curvilinear surfaces, 90% of the cumulative distribution of the measured data was less than 2mm, while for linear surfaces it was less than 6mm. Four behavioural effects were noticed: lateral deflection, reverse ‘stickiness’, hysteresis and instability in certain areas. These effects were studied in detail to determine how to either eliminate them or to minimize them through system design optimization. A computer simulation was also used to model the behaviour of the prototype and to gain further understanding of these effects. These analyses showed that the concept can be successfully used in curvilinear bone sculpting.Applied Science, Faculty ofMechanical Engineering, Department ofGraduat

Design and Validation of a CT- and MRI-Guided Robot for Percutaneous Needle Procedures

International audienceThis paper describes the design and evaluation of the second generation of a robotic system called the light puncture robot for thoracic and abdominopelvic interventional radiology procedures under CT and MRI guidance. It is mounted on the patient's body and positions and inserts the needle according to the trajectory and target chosen by the radiologist in the image. The mechanical design is described in detail along with its forward and inverse kinematics. The robot can be segmented and registered fully automatically in both imaging modalities. Phantom experiments in the CT scanner and preliminary feasibility experiments in the MRI are described, showing a targeting accuracy of 3.3 ± 1.7 mm in gelatin for depths ranging from 30 to 90 mm and needle orientations of -13° to +15° about normal from the patient's skin. A detailed error analysis is discussed along with potential improvements in the system. The potential clinical advantages of the system include higher targeting accuracy for complex dual obliquity trajectories, the need for fewer images, and improved accessibility to MRI-guided interventions

A realistic deformable prostate phantom for multimodal imaging and needle-insertion procedures

International audiencePurpose: Phantoms are a vital step for the preliminary validation of new image-guided procedures. In this paper, the authors present a deformable prostate phantom for use with multimodal imaging (end-fire or side-fire ultrasound, CT and MRI) and more specifically for transperineal or transrectal needle-insertion procedures. It is made of soft polyvinyl chloride (PVC) plastic and includes a prostate, a perineum, a rectum, a soft periprostatic surrounding and embedded targets for image registration and needle-targeting. Its main particularity is its realistic deformability upon manipulation. Methods: After a detailed manufacturing description, the imaging and mechanical characteristics of the phantom are described and evaluated. First, the speed of sound and stress-strain relationship of the PVC material used in the phantom are described, followed by an analysis of its storage, imaging, needle-insertion force, and deformability characteristics. Results: The average speed of sound in the phantom was measured to be 1380+/-20 m/s, while the stress-strain relationship was found to be viscoelastic and in the range of typical prostatic tissues. The mechanical and imaging characteristics of the phantom were found to remain stable at cooler storage temperatures. The phantom had clearly distinguishable morphology in all three imaging modalities, with embedded targets that could be precisely segmented, resulting in an average US-CT rigid registration error of 0.66 mm. The mobility of the phantom prostate upon needle insertion was between 2 and 4 mm, with rotations between 0and 2degrees, about the US probe head. Conclusion: The phantom's characteristics compare favorably with in vitro and in vivo measurements found in the literature. The authors believe that this realistic phantom could be of use to researchers studying new needle-based prostate diagnosis and therapy techniques

A 3D Ultrasound Robotic Prostate Brachytherapy System with Prostate Motion Tracking

International audienceThis paper describes a new three-dimensional (3D) ultrasound robotic prostate brachytherapy system. It uses a stationary 3D ultrasound probe rigidly fixed to a robotic needle insertion mechanism. The novelty of the system is its ability to track prostate motion intra-operatively to allow the dose planning and needle trajectories or depths to be adapted to take into account these motions. Prostate tracking is done using a fast 3D ultrasound registration algorithm previously validated for biopsy guidance. The 7 degree of freedom robot and ultrasound probe are calibrated together with an accuracy of 0.9mm, allowing the needles to be precisely inserted to the seed targets chosen in the reference ultrasound image. Experiments were conducted on mobile deformable synthetic prostate phantoms, using a prototype laboratory system. Results showed that, with prostate motions of up to 7mm, the system was able to reach the chosen targets with less than 2mm accuracy in the needle insertion direction. This measured accuracy included extrinsic measurement errors of up to 1.1mm. A preliminary cadaver feasibility study was also described, in preparation for more realistic experimentation of the system