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

Design and Development of a Surgical Robot for Needle-Based Medical Interventions

Lung cancer is the leading cause of cancer related deaths. If diagnosed in a timely manner, the treatment of choice is surgical resection of the cancerous lesions followed by radiotherapy. However, surgical resection may be too invasive for some patients due to old age or weakness. An alternative is minimally invasive needle-based interventions for cancer diagnosis and treatment. This project describes the design, analysis, development and experimental evaluation of a modular, compact, patient-mounted robotic manipulator for lung cancer diagnosis and treatment. In this regard, a novel parallel Remote Centre of Motion (RCM) mechanism is proposed for minimally invasive delivery of needle-based interventions. The proposed robot provides four degrees of freedom (DOFs) to orient and move a surgical needle within a spherical coordinate system. There is an analytical solution for the kinematics of the proposed parallel mechanism and the end-effectors motion is well-conditioned within the required workspace. The RCM is located beneath the skin surface to minimize the invasiveness of the surgical procedure while providing the required workspace to target the cancerous lesions. In addition, the proposed robot benefits from a design capable of measuring the interaction forces between the needle and the tissue. The experimental evaluation of the robot has proved its capability to accurately orient and move a surgical needle within the required workspace. Although this robotic system has been designed for the treatment of lung cancer, it is capable of performing other procedures in the thoracic or abdominal cavity such as liver cancer diagnosis and treatment

Design of a minimally invasive single port HDR brachytherapy applicator for the treatment of lung cancer

Cancer has become the number one cause of death in Canada and lung cancer is its deadliest form. Surgical resection remains as the treatment of choice for most patients; however, in many cases a less aggressive alternative such as brachytherapy may be preferable. Today, HDR brachytherapy is a relatively common procedure but with current techniques and equipment only tumours close to the main bronchi can be reached. This project describes the design, development and validation of a first prototype of an ultrasound-guided needle guidance system that would enable physicians to perform HDR brachytherapy for the treatment of lung cancer in a minimally invasive manner through the intercostal spaces. The development of the mechanical components is thoroughly described followed by the description of the electronic control system that was developed for this novel mechatronic medical tool. Finally through validation experiments, the approach was shown to be an accurate and viable approach for precisely reaching desired targets with a wide yet flexible needle

Tactile Sensing System for Lung Tumour Localization during Minimally Invasive Surgery

Video-assisted thoracoscopie surgery (VATS) is becoming a prevalent method for lung cancer treatment. However, VATS suffers from the inability to accurately relay haptic information to the surgeon, often making tumour localization difficult. This limitation was addressed by the design of a tactile sensing system (TSS) consisting of a probe with a tactile sensor and interfacing visualization software. In this thesis, TSS performance was tested to determine the feasibility of implementing the system in VATS. This was accomplished through a series of ex vivo experiments in which the tactile sensor was calibrated and the visualization software was modified to provide haptic information visually to the user, and TSS performance was compared using human and robot palpation methods, and conventional VATS instruments. It was concluded that the device offers the possibility of providing to the surgeon the haptic information lost during surgery, thereby mitigating one of the current limitations of VATS

Robotics-Assisted Needle Steering for Percutaneous Interventions: Modeling and Experiments

Needle insertion and guidance plays an important role in medical procedures such as brachytherapy and biopsy. Flexible needles have the potential to facilitate precise targeting and avoid collisions during medical interventions while reducing trauma to the patient and post-puncture issues. Nevertheless, error introduced during guidance degrades the effectiveness of the planned therapy or diagnosis. Although steering using flexible bevel-tip needles provides great mobility and dexterity, a major barrier is the complexity of needle-tissue interaction that does not lend itself to intuitive control. To overcome this problem, a robotic system can be employed to perform trajectory planning and tracking by manipulation of the needle base. This research project focuses on a control-theoretic approach and draws on the rich literature from control and systems theory to model needle-tissue interaction and needle flexion and then design a robotics-based strategy for needle insertion/steering. The resulting solutions will directly benefit a wide range of needle-based interventions. The outcome of this computer-assisted approach will not only enable us to perform efficient preoperative trajectory planning, but will also provide more insight into needle-tissue interaction that will be helpful in developing advanced intraoperative algorithms for needle steering. Experimental validation of the proposed methodologies was carried out on a state of-the-art 5-DOF robotic system designed and constructed in-house primarily for prostate brachytherapy. The system is equipped with a Nano43 6-DOF force/torque sensor (ATI Industrial Automation) to measure forces and torques acting on the needle shaft. In our setup, an Aurora electromagnetic tracker (Northern Digital Inc.) is the sensing device used for measuring needle deflection. A multi-threaded application for control, sensor readings, data logging and communication over the ethernet was developed using Microsoft Visual C 2005, MATLAB 2007 and the QuaRC Toolbox (Quanser Inc.). Various artificial phantoms were developed so as to create a realistic medium in terms of elasticity and insertion force ranges; however, they simulated a uniform environment without exhibiting complexities of organic tissues. Experiments were also conducted on beef liver and fresh chicken breast, beef, and ham, to investigate the behavior of a variety biological tissues

An Optimization-based Approach to Dosimetry Planning for Brachytherapy

Prostate cancer is the second leading cause of death from cancer in North American men, with a reported 32,050 deaths in the U.S. alone for 2010; lung cancer is reported as the number one leading cause of death from cancer in both men and women in North America, its estimated death toll in the U.S. alone in 2010 is over 157,000. One method of treating prostate cancer patients nowadays is by Low Dose Rate Brachytherapy, a process where radioactive seeds are placed in or near the tumor site to kill cancerous cells. For lung cancer, brachytherapy has begun to attract attention due to the advent of robotics assistance and there is increasing research currently in the area. While brachytherapy is gaining popularity as a commonly practiced method for treating cancer patients, the procedure itself has several drawbacks that require further research. One such drawback is that the dosimetry plan created based on the pre-operative imaging may not be accurate due to (a) the change in the tumor’s size as a result of the time elapsed between pre-operative imaging and seed implantation; and (b) movement of the organ under treatment from the position and orientation in pre­ operative imaging; this is particularly important in the case of lung brachytherapy as it would have to take into account lung deflation and respiratory and cardiac motions as well. In addition, seeds may be misplaced during implantation as a result of limitation of the manual or robotic procedures. When this happens, the final dose coverage of the tumor is no longer the same as the intended coverage in the dosimetry plan. In this thesis, the development, implementation and evaluation of two algorithms are presented.The first algorithm is the pre-planning algorithm, which aims to reduce the errors in the dosimetry plan caused by the change in the tumor’s size by providing a mechanism to perform dosimetry planning on-line. By doing this, the first algorithm can also eliminate the need for the patient to be imaged twice, so that the same set of images can be used for dosimetry planning as well as seed implantation. The second algorithm deals with intra-operative dynamic dose optimization, where real­ time seed compensation is performed to compensate for any seed misplacements so that an optimal final coverage can be achieved. The results of the experimental evaluation performed in this project indicate that these algorithms are feasible and have the potential to be applied in the operating room following appropriate animal and clinical validation

Towards Closed-loop, Robot Assisted Percutaneous Interventions under MRI Guidance

Image guided therapy procedures under MRI guidance has been a focused research area over past decade. Also, over the last decade, various MRI guided robotic devices have been developed and used clinically for percutaneous interventions, such as prostate biopsy, brachytherapy, and tissue ablation. Though MRI provides better soft tissue contrast compared to Computed Tomography and Ultrasound, it poses various challenges like constrained space, less ergonomic patient access and limited material choices due to its high magnetic field. Even after, advancements in MRI compatible actuation methods and robotic devices using them, most MRI guided interventions are still open-loop in nature and relies on preoperative or intraoperative images. In this thesis, an intraoperative MRI guided robotic system for prostate biopsy comprising of an MRI compatible 4-DOF robotic manipulator, robot controller and control application with Clinical User Interface (CUI) and surgical planning applications (3DSlicer and RadVision) is presented. This system utilizes intraoperative images acquired after each full or partial needle insertion for needle tip localization. Presented system was approved by Institutional Review Board at Brigham and Women\u27s Hospital(BWH) and has been used in 30 patient trials. Successful translation of such a system utilizing intraoperative MR images motivated towards the development of a system architecture for close-loop, real-time MRI guided percutaneous interventions. Robot assisted, close-loop intervention could help in accurate positioning and localization of the therapy delivery instrument, improve physician and patient comfort and allow real-time therapy monitoring. Also, utilizing real-time MR images could allow correction of surgical instrument trajectory and controlled therapy delivery. Two of the applications validating the presented architecture; closed-loop needle steering and MRI guided brain tumor ablation are demonstrated under real-time MRI guidance

Design, Development, and Evaluation of a Teleoperated Master-Slave Surgical System for Breast Biopsy under Continuous MRI Guidance

The goal of this project is to design and develop a teleoperated master-slave surgical system that can potentially assist the physician in performing breast biopsy with a magnetic resonance imaging (MRI) compatible robotic system. MRI provides superior soft-tissue contrast compared to other imaging modalities such as computed tomography or ultrasound and is used for both diagnostic and therapeutic procedures. The strong magnetic field and the limited space inside the MRI bore, however, restrict direct means of breast biopsy while performing real-time imaging. Therefore, current breast biopsy procedures employ a blind targeting approach based on magnetic resonance (MR) images obtained a priori. Due to possible patient involuntary motion or inaccurate insertion through the registration grid, such approach could lead to tool tip positioning errors thereby affecting diagnostic accuracy and leading to a long and painful process, if repeated procedures are required. Hence, it is desired to develop the aforementioned teleoperation system to take advantages of real-time MR imaging and avoid multiple biopsy needle insertions, improving the procedure accuracy as well as reducing the sampling errors. The design, implementation, and evaluation of the teleoperation system is presented in this dissertation. A MRI-compatible slave robot is implemented, which consists of a 1 degree of freedom (DOF) needle driver, a 3-DOF parallel mechanism, and a 2-DOF X-Y stage. This slave robot is actuated with pneumatic cylinders through long transmission lines except the 1-DOF needle driver is actuated with a piezo motor. Pneumatic actuation through long transmission lines is then investigated using proportional pressure valves and controllers based on sliding mode control are presented. A dedicated master robot is also developed, and the kinematic map between the master and the slave robot is established. The two robots are integrated into a teleoperation system and a graphical user interface is developed to provide visual feedback to the physician. MRI experiment shows that the slave robot is MRI-compatible, and the ex vivo test shows over 85%success rate in targeting with the MRI-compatible robotic system. The success in performing in vivo animal experiments further confirm the potential of further developing the proposed robotic system for clinical applications

New Mechatronic Systems for the Diagnosis and Treatment of Cancer

Both two dimensional (2D) and three dimensional (3D) imaging modalities are useful tools for viewing the internal anatomy. Three dimensional imaging techniques are required for accurate targeting of needles. This improves the efficiency and control over the intervention as the high temporal resolution of medical images can be used to validate the location of needle and target in real time. Relying on imaging alone, however, means the intervention is still operator dependent because of the difficulty of controlling the location of the needle within the image. The objective of this thesis is to improve the accuracy and repeatability of needle-based interventions over conventional techniques: both manual and automated techniques. This includes increasing the accuracy and repeatability of these procedures in order to minimize the invasiveness of the procedure. In this thesis, I propose that by combining the remote center of motion concept using spherical linkage components into a passive or semi-automated device, the physician will have a useful tracking and guidance system at their disposal in a package, which is less threatening than a robot to both the patient and physician. This design concept offers both the manipulative transparency of a freehand system, and tremor reduction through scaling currently offered in automated systems. In addressing each objective of this thesis, a number of novel mechanical designs incorporating an remote center of motion architecture with varying degrees of freedom have been presented. Each of these designs can be deployed in a variety of imaging modalities and clinical applications, ranging from preclinical to human interventions, with an accuracy of control in the millimeter to sub-millimeter range

Image-guided robots for dot-matrix tumor ablation

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 203-208).Advances in medical imaging now provides detailed images of solid tumors inside the body and miniaturized energy delivery systems enable tumor destruction through local heating powered by a thin electrode. However, the use of thermal ablation as a first line of treatment is limited due to the difficulty in accurately matching a desired treatment and a limited region of active heating around an electrode. The purpose of this research is to identify and quantify the current limitations of image-guided interventional procedures and subsequently develop a procedure and devices to enable accurate and efficient execution of image-based interventional plans and thus ablation of a tumor of any shape with minimal damage to surrounding tissue. Current limitations of probe placement for ablation therapy were determined by a detailed retrospective study of 50 representative CT-guided procedures. On average, 21 CT scans were performed for a given procedure (range 11-38), with the majority devoted to needle orientation and insertion (mean number of scans was 54%) and trajectory planning (mean number of scans was 19%). A regression analysis yielded that smaller and deeper lesions were associated with a higher number of CT scans for needle orientation and insertion; highlighting the difficulty in targeting. Another challenge identified was repositioning the instrument distal tip within tissue. The first robot is a patient-mounted device that aligns an instrument along a desired trajectory via two motor-actuated concentric, crossed, and partially nested hoops. A carriage rides in the hoops and grips and inserts an instrument via a two degree-of-freedom friction drive. An imagebased point-and-click user interface relates appropriate clicks on the medical images to robot commands. Mounting directly on the patient provides a sufficiently stable and safe platform for actuation and eliminates the need to compensate for chest motion; thereby reducing the cost and complexity compared to other devices. Phantom experiments in a realistic clinical setting demonstrated a mean targeting accuracy of 3.5 mm with an average of five CT scans. The second robot is for repositioning the distal tip of a medical instrument to adjacent points within tissue. The steering mechanism is based on the concept of substantially straightening a pre-curved Nitinol stylet by retracting it into a concentric outer cannula, and re-deploying it at different axial and rotational cannula positions. The proximal end of the cannula is attached to the distal end of a screw-spline that enables it to be translated and rotated with respect to the casing. Translation of the stylet relative to the cannula is achieved with a second concentric, nested smaller diameter screw that is constrained to rotate with the cannula. The robot mechanism is compatible with the CT images, light enough to be supported on a patient's chest or attached to standard stereotactic frames. Targeting experiments in a gelatin phantom demonstrated a mean targeting error of 1.8 mm between the stylet tip and that predicted with a kinematic model. Ultimately, these types of systems are envisioned being used together as part of a highly dexterous patient-mounted positioning platform that can accurately perform ablation of large and irregularly shaped tumors inside medical imaging machines - offering the potential to replace expensive and traumatic surgeries with minimally invasive out-patient procedures.by Conor James Walsh.Ph.D