Evolutionarily Optimized Electromagnetic Sensor Measurements for Robust Surgical Navigation

© 2001-2012 IEEE. Miniaturized electromagnetic sensors are increasingly introduced to navigate surgical instruments to anatomical targets during minimally invasive procedures, such as endoscopic surgery. These sensors are usually attached at the distal tips of surgical instruments to track their three-dimensional motion represented by the position and orientation in six degrees of freedom. Unfortunately, these sensors suffer from inaccurate measurements and jitter errors due to the patient movement (e.g., respiratory motion) and magnetic field distortion. This paper proposes an evolutionary computing strategy to optimize the sensor measurements and improve the tracking accuracy of surgical navigation. We modified two evolutionary computation algorithms and proposed adaptive particle swarm optimization (APSO) and observation-boosted differential evolution (OBDE) to enhance the navigation accuracy. The experimental results demonstrate that our modified algorithms to evolutionarily optimize electromagnetic sensor measurements can critically reduce the tracking error from 4.8 to 2.9 mm. In particular, OBDE outperforms APSO for electromagnetic endoscopic navigation

Hybrid inertial-manipulator based position tracking system for ultrasound imaging application

In medical field, ultrasound imaging is one of the imaging modalities that needs position tracking system (PTS) in enlarging field of view (FoV) of an image. The enlarged FoV will result easier scanning procedure, and produce more accurate and comprehensive results. To overcome the weakness of commercially available PTSs which suffer from interference and occlusion, many researchers proposed improved PTSs. However, the improved PTSs focused on the portability and compact design, neglecting the vertical scanning aspect which is also important in ultrasound imaging. Hence, this research presents the development of hybrid inertial-manipulator based PTS for 3-dimensional (3D) ultrasound imaging system which capable of measuring the horizontal and vertical scanning movements. The proposed PTS uses the combination of inertial measurement unit sensor and manipulator. The research involves design and evaluation processes for the PTS. Once the design process of the PTS is completed, forward kinematics is calculated using Denavit-Hartenberg conversion. The next step is to evaluate the accuracy and repeatability of the output of the designed PTS by comparing with five sets of reference trajectory of ABB robot. A comparison of the accuracy for the proposed PTS with three other available PTSs is done using the horizontal movement’s error. The experimental results showed high repeatability of position output reading of the designed PTS with standard deviation of 0.27 mm in all different movements and speeds. The proposed PTS is suitable to be used in ultrasound imaging as the error is less than 1.45 mm. Furthermore, the proposed PTS can measure the vertical scanning movement which is neglected in all the previous works, thus fulfilling the main objective of the research

ELECTROMAGNETIC TRACKER CHARACTERIZATION AND OPTIMAL TOOL DESIGN (WITH APPLICATIONS TO ENT SURGERY)

Electromagnetic tracking systems prove to have great potential for serving as the tracking component of image guided surgery (IGS) systems. However, despite their major advantage over other trackers in that they do not require line-of-sight to the sensors, their use has been limited primarily due to their inherent measurement distortion problem. Presented here are methods of mapping the measurement field distortion and results describing the distortion present in various environments. Further, a framework for calibration and characterization of the tracking system’s systematic error is presented. The error maps are used to generate polynomial models of the distortion that can be used to dynamically compensate for measurement errors. The other core theme of this work is related to optimal design of electromagnetically tracked tools; presented here are mathematical tools for analytically predicting error propagation and optimally configuring sensors on a tool. A software simulator, using a model of the magnetic field distortion, is used to further design and test these tools in a simulation of actual measurement environments before ever even being built. These tools are used to design and test a set of electromagnetically tracked instruments, specifically for ENT surgical applications

Development Methods and a Scenegraph Animation API for Cluster Driven Immersive Applications

This paper presents a scenegraph animation application programming interface (API), known as the Animation Engine, which was constructed for software developers to easily perform smooth transitions and manipulations to scenegraph nodes. A developer can use one line of code to enter the property, end state and number of frames to describe the animation, then the Animation Engine handles the rest in the background. The goal of the Animation Engine is to provide a simple API that integrates into existing applications with minimal effort. Additionally, techniques to improve virtual reality (VR) application performance on a large computer cluster are presented. These techniques include maintaining high frame rates with 4096 × 4096 pixel textures, eliminating extraneous network traffic and reducing long model loading time. To demonstrate the Animation Engine and the development techniques, an application known as the Virtual Universe was created. The Virtual Universe, designed to run in a six walled CAVE, allows users to freely explore a set of space themed environments. The architecture and development techniques for writing a stable immersive VR application on a large computer cluster, in addition to the creation of the Animation Engine, is presented in this paper

A 3D US Guidance System for Permanent Breast Seed Implantation: Development and Validation

Permanent breast seed implantation (PBSI) is a promising breast radiotherapy technique that suffers from operator dependence. We propose and have developed an intraoperative 3D ultrasound (US) guidance system for PBSI. A tracking arm mounted to a 3D US scanner registers a needle template to the image. Images were validated for linear and volumetric accuracy, and image quality in a volunteer. The tracking arm was calibrated, and the 3D image registered to the scanner. Tracked and imaged needle positions were compared to assess accuracy and a patient-specific phantom procedure guided with the system. Median/mean linear and volumetric error was ±1.1% and ±4.1%, respectively, with clinically suitable volunteer scans. Mean tracking arm error was 0.43mm and 3D US target registration error ≤0.87mm. Mean needle tip/trajectory error was 2.46mm/1.55°. Modelled mean phantom procedure seed displacement was 2.50mm. To our knowledge, this is the first reported PBSI phantom procedure with intraoperative 3D image guidance

Aerospace medicine and biology: A continuing bibliography with indexes, supplement 162, January 1977

This bibliography lists 189 reports, articles, and other documents introduced into the NASA scientific and technical information system in December 1976

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

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

Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 182, July 1978

This bibliography lists 165 reports, articles, and other documents introduced into the NASA scientific and technical information system in June 1978