Three-dimensional ultrasound image-guided robotic system for accurate microwave coagulation of malignant liver tumours

Background The further application of conventional ultrasound (US) image-guided microwave (MW) ablation of liver cancer is often limited by two-dimensional (2D) imaging, inaccurate needle placement and the resulting skill requirement. The three-dimensional (3D) image-guided robotic-assisted system provides an appealing alternative option, enabling the physician to perform consistent, accurate therapy with improved treatment effectiveness. Methods Our robotic system is constructed by integrating an imaging module, a needle-driven robot, a MW thermal field simulation module, and surgical navigation software in a practical and user-friendly manner. The robot executes precise needle placement based on the 3D model reconstructed from freehand-tracked 2D B-scans. A qualitative slice guidance method for fine registration is introduced to reduce the placement error caused by target motion. By incorporating the 3D MW specific absorption rate (SAR) model into the heat transfer equation, the MW thermal field simulation module determines the MW power level and the coagulation time for improved ablation therapy. Two types of wrists are developed for the robot: a ‘remote centre of motion’ (RCM) wrist and a non-RCM wrist, which is preferred in real applications. Results The needle placement accuracies were < 3 mm for both wrists in the mechanical phantom experiment. The target accuracy for the robot with the RCM wrist was improved to 1.6 ± 1.0 mm when real-time 2D US feedback was used in the artificial-tissue phantom experiment. By using the slice guidance method, the robot with the non-RCM wrist achieved accuracy of 1.8 ± 0.9 mm in the ex vivo experiment; even target motion was introduced. In the thermal field experiment, a 5.6% relative mean error was observed between the experimental coagulated neurosis volume and the simulation result. Conclusion The proposed robotic system holds promise to enhance the clinical performance of percutaneous MW ablation of malignant liver tumours. Copyright © 2010 John Wiley & Sons, Ltd.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78054/1/313_ftp.pd

CO-ROBOTIC ULTRASOUND IMAGING: A COOPERATIVE FORCE CONTROL APPROACH

Ultrasound (US) imaging remains one of the most commonly used imaging modalities in medical practice due to its low cost and safety. However, 63-91% of ultrasonographers develop musculoskeletal disorders due to the effort required to perform imaging tasks. Robotic ultrasound (RUS), the application of robotic systems to assist ultrasonographers in ultrasound scanning procedures, has been proposed in literature and recently deployed in clinical settings using limited degree-of-freedom (DOF) systems. An example of this includes breast-scanning systems, which allow one-DOF translation of a large ultrasound array in order to capture patients’ breast scans and minimize sonographer effort while preserving a desired clinical outcome. Recently, the robotic industry has evolved to provide light-weight, compact, accurate, and cost-effective manipulators. We leverage this new reality in able to provide ultrasonographers with a full 6-DOF system that provides force assistance to facilitate US image acquisition. Admittance robot control allows for smooth human-machine interaction in a desired task. In the case of RUS, force control is capable of assisting sonographers in facilitating and even improving the imaging results of typical procedures. We propose a new system setup for collaborative force control in US applications. This setup consists of the 6-DOF UR5 industrial robot, and a 6-axes force sensor attached to the robot tooltip, which in turn has an US probe attached to it through a custom-designed probe attachment mechanism. Additionally, an independent one-axis load cell is placed inside this attachment device and used to measure the contact force between the probe and the patient’s anatomy in real time and independent of any other forces. As the sonographer guides the US probe, the robot collaborates with the hand motions, following the path of the user. When imaging, the robot can offer assistance to the sonographer by augmenting the forces applied by him or her, thereby lessening the physical effort required as well as the resulting strain. Additional benefits include force and velocity limiting for patient safety and robot motion constraints for particular imaging tasks. Initial results of a conducted user study show the feasibility of implementing the presented robot-assisted system in a clinical setting

Medical Ultrasound Imaging and Interventional Component (MUSiiC) Framework for Advanced Ultrasound Image-guided Therapy

Medical ultrasound (US) imaging is a popular and convenient medical imaging modality thanks to its mobility, non-ionizing radiation, ease-of-use, and real-time data acquisition. Conventional US brightness mode (B-Mode) is one type of diagnostic medical imaging modality that represents tissue morphology by collecting and displaying the intensity information of a reflected acoustic wave. Moreover, US B-Mode imaging is frequently integrated with tracking systems and robotic systems in image-guided therapy (IGT) systems. Recently, these systems have also begun to incorporate advanced US imaging such as US elasticity imaging, photoacoustic imaging, and thermal imaging. Several software frameworks and toolkits have been developed for US imaging research and the integration of US data acquisition, processing and display with existing IGT systems. However, there is no software framework or toolkit that supports advanced US imaging research and advanced US IGT systems by providing low-level US data (channel data or radio-frequency (RF) data) essential for advanced US imaging. In this dissertation, we propose a new medical US imaging and interventional component framework for advanced US image-guided therapy based on networkdistributed modularity, real-time computation and communication, and open-interface design specifications. Consequently, the framework can provide a modular research environment by supporting communication interfaces between heterogeneous systems to allow for flexible interventional US imaging research, and easy reconfiguration of an entire interventional US imaging system by adding or removing devices or equipment specific to each therapy. In addition, our proposed framework offers real-time synchronization between data from multiple data acquisition devices for advanced iii interventional US imaging research and integration of the US imaging system with other IGT systems. Moreover, we can easily implement and test new advanced ultrasound imaging techniques inside the proposed framework in real-time because our software framework is designed and optimized for advanced ultrasound research. The system’s flexibility, real-time performance, and open-interface are demonstrated and evaluated through performing experimental tests for several applications

SMART IMAGE-GUIDED NEEDLE INSERTION FOR TISSUE BIOPSY

M.S

Medical Robotics

The first generation of surgical robots are already being installed in a number of operating rooms around the world. Robotics is being introduced to medicine because it allows for unprecedented control and precision of surgical instruments in minimally invasive procedures. So far, robots have been used to position an endoscope, perform gallbladder surgery and correct gastroesophogeal reflux and heartburn. The ultimate goal of the robotic surgery field is to design a robot that can be used to perform closed-chest, beating-heart surgery. The use of robotics in surgery will expand over the next decades without any doubt. Minimally Invasive Surgery (MIS) is a revolutionary approach in surgery. In MIS, the operation is performed with instruments and viewing equipment inserted into the body through small incisions created by the surgeon, in contrast to open surgery with large incisions. This minimizes surgical trauma and damage to healthy tissue, resulting in shorter patient recovery time. The aim of this book is to provide an overview of the state-of-art, to present new ideas, original results and practical experiences in this expanding area. Nevertheless, many chapters in the book concern advanced research on this growing area. The book provides critical analysis of clinical trials, assessment of the benefits and risks of the application of these technologies. This book is certainly a small sample of the research activity on Medical Robotics going on around the globe as you read it, but it surely covers a good deal of what has been done in the field recently, and as such it works as a valuable source for researchers interested in the involved subjects, whether they are currently “medical roboticists” or not

SUBJECT-SPECIFIC 4D ULTRASOUND LIVER MODEL AND DYNAMIC PHANTOM FOR ROBOTIC-ASSISTED LIVER BIOPSY STUDY

Ph.DDOCTOR OF PHILOSOPH

REAL-TIME ELASTOGRAPHY SYSTEMS

Ultrasound elastography is a technique that is often used to detect cancerous tumors and monitor ablation therapy by detecting changes in the stiffness of the underlying tissue. This technique is a computationally expensive due to the extensive searching between two raw ultrasound images, that are called radio frequency images. This thesis explores various methods to accelerate the computation required for the elastography technique to allow use during surgery. This thesis is divided into three parts. We begin by exploring acceleration techniques, including multithreading techniques, asynchronous computing, and acceleration of the graphics processing unit (GPU). Elastography algorithms are often affected by out-of-plane motion due to several external factors, such as hand tremors and incorrect palpation motion, amongst others. In this thesis, we implemented an end-to-end system that integrates an external tracker system to detect the in-plane motion of two radio frequency (RF) data slices. This in-plane detection helps to reduce de-correlated RF slices and produces a consistent elastography output. We also explore the integration of a da Vinci Surgical Robot to provide stable palpation motion during the surgery. The external tracker system suffers from interference due to ferromagnetic materials present in the operation theater in the case of an electromagnetic tracker, while optical and camera-based tracking systems are restricted due to human, object and patient interference in the path of sight and complete or partial occlusion of the tracking sensors. Additionally, these systems must be calibrated to give the position of the tracked objects with respect to the trackers. Although calibration and trackers are helpful for inter-modality registration, we focus on a tracker-less method to determine the in-plane motion of two RF slices. Our technique divides the two input RF images into regions of interest and performs elastography on RF lines that encapsulate those regions of interest. Finally, we implemented the world’s first known five-dimensional ultrasound system. We built the five-dimensional ultrasound system by combining a 3D B-mode volume and a 3D elastography volume visualized over time. A user controlled multi-dimensional transfer function is used to differentiate between the 3D B-mode and the 3D elastography volume

Enabling technologies for MRI guided interventional procedures

This dissertation addresses topics related to developing interventional assistant devices for Magnetic Resonance Imaging (MRI). MRI can provide high-quality 3D visualization of target anatomy and surrounding tissue, but the benefits can not be readily harnessed for interventional procedures due to difficulties associated with the use of high-field (1.5T or greater) MRI. Discussed are potential solutions to the inability to use conventional mecha- tronics and the confined physical space in the scanner bore. This work describes the development of two apparently dissimilar systems that repre- sent different approaches to the same surgical problem - coupling information and action to perform percutaneous (through the skin) needle placement with MR imaging. The first system addressed takes MR images and projects them along with a surgical plan directly on the interventional site, thus providing in-situ imaging. With anatomical images and a corresponding plan visible in the appropriate pose, the clinician can use this information to perform the surgical action. My primary research effort has focused on a robotic assistant system that overcomes the difficulties inherent to MR-guided procedures, and promises safe and reliable intra-prostatic needle placement inside closed high-field MRI scanners. The robot is a servo pneumatically operated automatic needle guide, and effectively guides needles under real- time MR imaging. This thesis describes development of the robotic system including requirements, workspace analysis, mechanism design and optimization, and evaluation of MR compatibility. Further, a generally applicable MR-compatible robot controller is de- veloped, the pneumatic control system is implemented and evaluated, and the system is deployed in pre-clinical trials. The dissertation concludes with future work and lessons learned from this endeavor