InterNAV3D: A Navigation Tool for Robot-Assisted Needle-Based Intervention for the Lung

Lung cancer is one of the leading causes of cancer deaths in North America. There are recent advances in cancer treatment techniques that can treat cancerous tumors, but require a real-time imaging modality to provide intraoperative assistive feedback. Ultrasound (US) imaging is one such modality. However, while its application to the lungs has been limited because of the deterioration of US image quality (due to the presence of air in the lungs); recent work has shown that appropriate lung deflation can help to improve the quality sufficiently to enable intraoperative, US-guided robotics-assisted techniques to be used. The work described in this thesis focuses on this approach. The thesis describes a project undertaken at Canadian Surgical Technologies and Advanced Robotics (CSTAR) that utilizes the image processing techniques to further enhance US images and implements an advanced 3D virtual visualization software approach. The application considered is that for minimally invasive lung cancer treatment using procedures such as brachytherapy and microwave ablation while taking advantage of the accuracy and teleoperation capabilities of surgical robots, to gain higher dexterity and precise control over the therapy tools (needles and probes). A number of modules and widgets are developed and explained which improve the visibility of the physical features of interest in the treatment and help the clinician to have more reliable and accurate control of the treatment. Finally the developed tools are validated with extensive experimental evaluations and future developments are suggested to enhance the scope of the applications

SEED LOCALIZATION IN IMAGE-GUIDED PROSTATE BRACHYTHERAPY INTRAOPERATIVE DOSIMETRY SYSTEMS

Prostate cancer is the most common cancer among men in the United States. Many treatments are available, but prostate brachytherapy is acknowledged as a standard treatment for patients with localized cancer. Prostate brachytherapy is a minimally invasive surgery involving the permanent implantation of approximately 100 grain-sized radioactive seeds into the prostate. While effective, contemporary practice of brachytherapy is suboptimal because it spreads the stages of planning, implant, and dosimetry over several weeks. Although brachytherapy is now moving towards intraoperative treatment planning (ITP) which integrates all three stages into a single day in the operating room,the American Brachytherapy Society states, “the major current limitation of ITP is the inability to localize the seeds in relation to the prostate.” While the procedure is traditionally guided by transrectal ultrasound (TRUS), poor image quality prevents TRUS from accurately localizing seeds to compute dosimetry intraoperatively. Alternative methods exist, but are generally impractical to implement in clinics worldwide. The subject of this dissertation is the development of two intraoperative dosimetry systems to practically solve the problem of seed localization in ITP. The first system fuses TRUS with X-ray fluoroscopy using the ubiquitous non-isocentric mobile C-arm.The primary contributions of this dissertation include an automatic fiducial and seed segmentation algorithm for fluoroscopic images, as well as a next generation intraoperative dosimetry system based on a fiducial with seed-like markers. Results from over 30 patients prove that both contributions are significant for localizing seeds with high accuracy and demonstrate the capability of detecting cold spots. The second intraoperative dosimetry system is based on photoacoustic imaging, and uses the already implemented TRUS probe to detect ultrasonic waves converted from electromagnetic waves generated by a laser. The primary contributions of this dissertation therefore also include a prototype benchtop photoacoustic system and an improved clinical version usable in the operating room. Results from gelatin phantoms, an ex vivo dog prostate, and an in vivo dog study reveal that multiple seeds are clearly visible with high contrast using photoacoustic imaging at clinically safe laser energies.Together, both systems significantly progress the latest technologies to provide optimal care to patients through ITP

A Novel System and Image Processing for Improving 3D Ultrasound-guided Interventional Cancer Procedures

Image-guided medical interventions are diagnostic and therapeutic procedures that focus on minimizing surgical incisions for improving disease management and reducing patient burden relative to conventional techniques. Interventional approaches, such as biopsy, brachytherapy, and ablation procedures, have been used in the management of cancer for many anatomical regions, including the prostate and liver. Needles and needle-like tools are often used for achieving planned clinical outcomes, but the increased dependency on accurate targeting, guidance, and verification can limit the widespread adoption and clinical scope of these procedures. Image-guided interventions that incorporate 3D information intraoperatively have been shown to improve the accuracy and feasibility of these procedures, but clinical needs still exist for improving workflow and reducing physician variability with widely applicable cost-conscience approaches. The objective of this thesis was to incorporate 3D ultrasound (US) imaging and image processing methods during image-guided cancer interventions in the prostate and liver to provide accessible, fast, and accurate approaches for clinical improvements. An automatic 2D-3D transrectal ultrasound (TRUS) registration algorithm was optimized and implemented in a 3D TRUS-guided system to provide continuous prostate motion corrections with sub-millimeter and sub-degree error in 36 ± 4 ms. An automatic and generalizable 3D TRUS prostate segmentation method was developed on a diverse clinical dataset of patient images from biopsy and brachytherapy procedures, resulting in errors at gold standard accuracy with a computation time of 0.62 s. After validation of mechanical and image reconstruction accuracy, a novel 3D US system for focal liver tumor therapy was developed to guide therapy applicators with 4.27 ± 2.47 mm error. The verification of applicators post-insertion motivated the development of a 3D US applicator segmentation approach, which was demonstrated to provide clinically feasible assessments in 0.246 ± 0.007 s. Lastly, a general needle and applicator tool segmentation algorithm was developed to provide accurate intraoperative and real-time insertion feedback for multiple anatomical locations during a variety of clinical interventional procedures. Clinical translation of these developed approaches has the potential to extend the overall patient quality of life and outcomes by improving detection rates and reducing local cancer recurrence in patients with prostate and liver cancer

Traitement et exploration d'images TDM pour l'évaluation des bioprothèses valvulaires aortiques

Le but de cette étude est d évaluer la faisabilité de l analyse tomodensitométrique 3D des bioprothèses aortiques pour faciliter leur évaluation morphologique durant le suivi et d aider la sélection de cas et améliorer la planification d une procédure valvein-valve. Le challenge était représenté par le rehaussement des feuillets valvulaires, en raison d images très bruitées. Un angio-scanner synchronisé était réalisé chez des patients porteurs d une bioprotèses aortique dégénérée avant réintervention (images in-vivo). Différentes méthodes pour la réduction du bruit étaient proposées. La reconstruction tridimensionnelle des bioprothèses était réalisée en utilisant des méthodes de segmentation de régions par "sticks". Après réopération ces méthodes étaient appliquées aux images scanner des bioprothèses explantées (images ex-vivo) et utilisées comme référence. La réduction du bruit obtenue par le filtre stick modifié montrait meilleurs résultats en rapport signal/bruit en comparaison aux filtres de diffusion anisotropique. Toutes les méthodes de segmentation ont permis une reconstruction 3D des feuillets. L analyse qualitative a montré une bonne concordance entre les images obtenues in-vivo et les altérations des bioprothèses. Les résultats des différentes méthodes étaient comparés par critères volumétriques et discutés. Les bases d'une première approche de visualisation spatio-temporelle d'images TDM 3D+T de la prothèse valvulaire ont été proposés. Elle implique des techniques de rendu volumique et de compensation de mouvement. Son application à la valve native a aussi été envisagée. Les images scanner des bioprothèses aortiques nécessitent un traitement de débruitage et de réduction des artéfacts de façon à permettre le rehaussement des feuillets prothétiques. Les méthodes basées sticks semblent constituer une approche pertinente pour caractériser morphologiquement la dégénérescence des bioprothèses.The aim of the study was to assess the feasibility of CT based 3D analysis of degenerated aortic bioprostheses to make easier their morphological assessment. This could be helpful during regular follow-up and for case selection, improved planning and mapping of valve-in-valve procedure. The challenge was represented by leaflets enhancement because of highly noised CT images. Contrast-enhanced ECG-gated CT scan was performed in patients with degenerated aortic bioprostheses before reoperation (in-vivo images). Different methods for noise reduction were tested and proposed. 3D reconstruction of bioprostheses components was achieved using stick based region segmentation methods. After reoperation, segmentation methods were applied to CT images of the explanted prostheses (exvivo images). Noise reduction obtained by improved stick filter showed best results in terms of signal to noise ratio comparing to anisotropic diffusion filters. All segmentation methods applied to the best phase of in-vivo images allowed 3D bioprosthetic leaflets reconstruction. Explanted bioprostheses CT images were also processed and used as reference. Qualitative analysis revealed a good concordance between the in-vivo images and the bioprostheses alterations. Results from different methods were compared by means of volumetric criteria and discussed. A first approach for spatiotemporal visualization of 3D+T images of valve bioprosthesis has been proposed. Volume rendering and motion compensation techniques were applied to visualize different phases of CT data. Native valve was also considered. ECG-gated CT images of aortic bioprostheses need a preprocessing to reduce noise and artifacts in order to enhance prosthetic leaflets. Stick based methods seems to provide an interesting approach for the morphological characterization of degenerated bioprostheses.RENNES1-Bibl. électronique (352382106) / SudocSudocFranceF