Real-time Knowledge-based Fuzzy Logic Model for Soft Tissue Deformation

In this research, the improved mass spring model is presented to simulate the human liver deformation. The underlying MSM is redesigned where fuzzy knowledge-based approaches are implemented to determine the stiffness values. Results show that fuzzy approaches are in very good agreement to the benchmark model. The novelty of this research is that for liver deformation in particular, no specific contributions in the literature exist reporting on real-time knowledge-based fuzzy MSM for liver deformation

Computer simulated needle manipulation of Chinese acupuncture with realistic haptic feedback.

Leung Ka Man.Thesis submitted in: August 2002.Thesis (M.Phil.)--Chinese University of Hong Kong, 2003.Includes bibliographical references (leaves 81-84).Abstracts in English and Chinese.Abstract --- p.iiAcknowledgements --- p.ivContents --- p.vList of Figures --- p.viiiList of Tables --- p.xChapter 1. --- Introduction --- p.1Chapter 1.1 --- Surgical Needle Simulation --- p.4Chapter 1.1.1 --- Data Source --- p.5Chapter 1.1.2 --- Computer-aided training simulation --- p.6Chapter 1.1.3 --- Existing Systems --- p.8Chapter 1.2 --- Research Goal --- p.10Chapter 1.3 --- Organization of this Thesis --- p.12Chapter 2. --- Haptization of Needle Interactions --- p.13Chapter 2.1 --- Data Collection --- p.13Chapter 2.1.1 --- Force Measurement --- p.14Chapter 2.1.2 --- Data Correlation --- p.17Chapter 2.1.3 --- Expert Opinion --- p.18Chapter 2.2 --- Haptic Display Devices --- p.18Chapter 2.2.1 --- General-purpose Devices --- p.19Chapter 2.2.2 --- Tailor-made Devices --- p.20Chapter 2.3 --- Haptic Models for Tissues --- p.21Chapter 2.3.1 --- Stiffness Models --- p.21Chapter 2.3.2 --- Friction Models --- p.22Chapter 2.3.3 --- Modelling of needle operations --- p.23Chapter 2.4 --- Chapter Summary --- p.24Chapter 3. --- Haptic Rendering of Bi-directional Needle Manipulation --- p.25Chapter 3.1 --- Data Source and Pre-processing --- p.26Chapter 3.1.1 --- Virtual Body Surface Construction --- p.28Chapter 3.1.2 --- Tissue Mapping for Haptic Rendering --- p.29Chapter 3.2 --- The PHANToM´ёØ Haptic Device --- p.31Chapter 3.3 --- Force Profile Analysis --- p.33Chapter 3.4 --- Haptic Model Construction --- p.37Chapter 3.4.1 --- Skin --- p.41Chapter 3.4.2 --- Adipose Tissue --- p.48Chapter 3.4.3 --- Muscle --- p.49Chapter 3.4.4 --- Bone --- p.50Chapter 3.5 --- Force Composition --- p.51Chapter 3.5.1 --- Structure Weight Compensation --- p.52Chapter 3.5.2 --- Path Constraint Force --- p.52Chapter 3.5.3 --- Needle Axial Force --- p.53Chapter 3.6 --- Interactive Calibration --- p.60Chapter 3.7 --- Skin Deformation --- p.61Chapter 3.8 --- Chapter Summary --- p.63Chapter 4. --- Parallel Visual-Haptic Rendering --- p.64Chapter 4.1 --- Parallel Network Architecture --- p.64Chapter 4.2 --- Visual Rendering Pipeline --- p.65Chapter 4.3 --- Haptic Rendering Pipeline --- p.67Chapter 4.4 --- Chapter Summary --- p.67Chapter 5. --- User Interface --- p.68Chapter 5.1 --- Needle Practice --- p.68Chapter 5.1.1 --- Moving Mode --- p.69Chapter 5.1.2 --- Acupuncture Atlas --- p.70Chapter 5.1.3 --- Training Results --- p.70Chapter 5.1.4 --- User Controls --- p.71Chapter 5.2 --- Device Calibration --- p.72Chapter 5.3 --- Model Settings --- p.72Chapter 5.4 --- Chapter Summary --- p.72Chapter 6. --- Conclusion --- p.73Chapter 6.1 --- Research Summary --- p.73Chapter 6.2 --- Suggested Improvement --- p.74Chapter 6.3 --- Future Research Works --- p.75Appendix A: Mapping Table for Tissues --- p.76Appendix B: Incremental Viscoelastic Model --- p.78Appendix C: Model Parameter Values --- p.80Bibliography --- p.8

Essential techniques for improving visual realism of laparoscopic surgery simulation.

With the prevalence of laparoscopic surgery, the request for reliable training and assessment is becoming increasingly important. The traditional way of training is both time consuming and cost intensive, and may cause ethical or moral issues. With the development of computer technologies, virtual reality has entered the world of consumer electronics as a new way to enhance tactile and visual sensory experiences. Virtual reality based surgical skill training gradually becomes an effective supplementary to the traditional laparoscopic skill training in many surgical theatres. To provide high fidelity virtual surgery training experiences, the presentation of the virtual world should have the same level of realism as what surgeons see and feel during real operations. However, the weak computing power limits the potential level of details on the graphics presentation and physical behaviour of virtual objects, which will further influence the fidelity of tactile interaction. Achieving visual realism (realistic graphics presentation and accurate physical behaviour) and good user experience using limited computing resources is the main challenge for laparoscopic surgery simulation. The topic of visual realism in laparoscopic surgery simulation has not been well researched. This topic mainly relates to the area of 3D anatomy modeling, soft body simulation and rendering. Current researches in computer graphics and game communities are not tailored for laparoscopic surgery simulation. The direct use of those techniques in developing surgery simulators will often result in poor quality anatomy model, inaccurate simulation, low fidelity visual effect, poor user experience and inefficient production pipeline, which significantly influence the visual realism of the virtual world. The development of laparoscopic surgery simulator is an interdiscipline of computer graphics, computational physics and haptics. However, current researches barely focus on the study of tailored techniques and efficient production pipeline which often result in the long term research cycle and daunting cost for simulator development. This research is aiming at improving the visual realism of laparoscopic surgery simulation from the perspective of computer graphics. In this research, a set of tailor techniques have been proposed to improve the visual realism for laparoscopic surgery simulation. For anatomy modeling, an automatic and efficient 3D anatomy conversion pipeline is proposed which can convert bad quality 3D anatomy into simulation ready state while preserving the original model’s surface parameterization property. For simulation, a soft tissue simulation pipeline is pro- posed which can provide multi-layer heterogeneous soft tissue modeling and intuitive physically editable simulation based on uniform polynomial based hyperelastic material representation. For interaction, a collision detection and interaction system based on adaptive circumphere structure is proposed which supports robust and efficient sliding con- tact, energized dissection and clip. For rendering, a multi-layer soft tissue rendering pipeline is proposed which decomposed the multi-layer structure of soft tissue into corresponding material asset required by state-of-art rendering techniques. Based on this research, a system framework for building a laparoscopic surgery simulator is also proposed to test the feasibility of those tailored techniques

Toward a Realistic Simulation of Organ Dissection

International audienceWhilst laparoscopic surgical simulators are becoming increasingly realistic they cannot, as yet, fully replicate the experience of live surgery. In particular tissue dissection in one task that is particularly challenging to replicate. Limitation of current attempts to simulate tissue dissection include: poor visual rendering; over simplification of the task and; unrealistic tissue properties. In an effort to generate a more realistic model of tissue dissection in laparoscopic surgery we propose a novel method based on task analysis. Initially we have chosen to model only the basic geometrics of this task rather than a whole laparoscopic procedure. Preliminary work has led to the development of a real time simulator performing organ dissection with a haptic thread at 1000Hz. A virtual cutting tool, manipulated through a haptic device, in combination with 1D and 2D soft-tissue models accurately replicate the process of laparoscopic tissue dissection

VISIO-HAPTIC DEFORMABLE MODEL FOR HAPTIC DOMINANT PALPATION SIMULATOR

Vision and haptic are two most important modalities in a medical simulation. While visual cues assist one to see his actions when performing a medical procedure, haptic cues enable feeling the object being manipulated during the interaction. Despite their importance in a computer simulation, the combination of both modalities has not been adequately assessed, especially that in a haptic dominant environment. Thus, resulting in poor emphasis in resource allocation management in terms of effort spent in rendering the two modalities for simulators with realistic real-time interactions. Addressing this problem requires an investigation on whether a single modality (haptic) or a combination of both visual and haptic could be better for learning skills in a haptic dominant environment such as in a palpation simulator. However, before such an investigation could take place one main technical implementation issue in visio-haptic rendering needs to be addresse

Realistic tool-tissue interaction models for surgical simulation and planning

Surgical simulators present a safe and potentially effective method for surgical training, and can also be used in pre- and intra-operative surgical planning. Realistic modeling of medical interventions involving tool-tissue interactions has been considered to be a key requirement in the development of high-fidelity simulators and planners. The soft-tissue constitutive laws, organ geometry and boundary conditions imposed by the connective tissues surrounding the organ, and the shape of the surgical tool interacting with the organ are some of the factors that govern the accuracy of medical intervention planning.\ud \ud This thesis is divided into three parts. First, we compare the accuracy of linear and nonlinear constitutive laws for tissue. An important consequence of nonlinear models is the Poynting effect, in which shearing of tissue results in normal force; this effect is not seen in a linear elastic model. The magnitude of the normal force for myocardial tissue is shown to be larger than the human contact force discrimination threshold. Further, in order to investigate and quantify the role of the Poynting effect on material discrimination, we perform a multidimensional scaling study. Second, we consider the effects of organ geometry and boundary constraints in needle path planning. Using medical images and tissue mechanical properties, we develop a model of the prostate and surrounding organs. We show that, for needle procedures such as biopsy or brachytherapy, organ geometry and boundary constraints have more impact on target motion than tissue material parameters. Finally, we investigate the effects surgical tool shape on the accuracy of medical intervention planning. We consider the specific case of robotic needle steering, in which asymmetry of a bevel-tip needle results in the needle naturally bending when it is inserted into soft tissue. We present an analytical and finite element (FE) model for the loads developed at the bevel tip during needle-tissue interaction. The analytical model explains trends observed in the experiments. We incorporated physical parameters (rupture toughness and nonlinear material elasticity) into the FE model that included both contact and cohesive zone models to simulate tissue cleavage. The model shows that the tip forces are sensitive to the rupture toughness. In order to model the mechanics of deflection of the needle, we use an energy-based formulation that incorporates tissue-specific parameters such as rupture toughness, nonlinear material elasticity, and interaction stiffness, and needle geometric and material properties. Simulation results follow similar trends (deflection and radius of curvature) to those observed in macroscopic experimental studies of a robot-driven needle interacting with gels

Smart Textiles in Building and Living Applications: WG4 CONTEXT Insight on Elderly and Healthcare Environments

Over the past 30 years, the development of new technologies and especially of smart textiles has unavoidably led to new applications of traditional textiles in the built environment. Depending on special constructional needs (i.e., acoustic insulation, thermal insulation, shading system, etc.) or health monitoring and supporting needs (i.e., for patients with chronical disease, etc.), an increasing number of possible applications has been proposed to improve human well-being. This is especially the case for healthcare environments (like elderly or nursing homes, etc.), but also educational environments (like schools, etc.) where young or old customers can benefit from technological innovation in several ways. As an ongoing activity of WG4 members for the CA17107 “CONTEXT” European research network, this study presents a review on selected applications for building and living solutions, with special attention to healthcare environments, giving evidence of major outcomes and potentials for smart textiles-based products

Soft volume simulation using a deformable surface model

The aim of the research is to contribute to the modelling of deformable objects, such as soft tissues in medical simulation. Interactive simulation for medical training is a concept undergoing rapid growth as the underlying technologies support the increasingly more realstic and functional training environments. The prominent issues in the deployment of such environments centre on a fine balance between the accuracy of the deformable model and real-time interactivity. Acknowledging the importance of interacting with non-rigid materials such as the palpation of a breast for breast assessment, this thesis has explored the physics-based modelling techniques for both volume and surface approach. This thesis identified that the surface approach based on the mass spring system (MSS) has the benefits of rapid prototyping, reduced mesh complexity, computational efficiency and the support for large material deformation compared to the continuum approach. However, accuracy relative to real material properties is often over looked in the configuration of the resulting model. This thesis has investigated the potential and the feasibility of surface modelling for simulating soft objects regardless of the design of the mesh topology and the non-existence of internal volume discretisation. The assumptions of the material parameters such as elasticity, homogeneity and incompressibility allow a reduced set of material values to be implemented in order to establish the association with the surface configuration. A framework for a deformable surface model was generated in accordance with the issues of the estimation of properties and volume behaviour corresponding to the material parameters. The novel extension to the surface MSS enables the tensile properties of the material to be integrated into an enhanced configuration despite its lack of volume information. The benefits of the reduced complexity of a surface model are now correlated with the improved accuracy in the estimation of properties and volume behaviour. Despite the irregularity of the underlying mesh topology and the absence of volume, the model reflected the original material values and preserved volume with minimal deviations. Global deformation effect which is essential to emulate the run time behaviour of a real soft material upon interaction, such as the palpation of a generic breast, was also demonstrated, thus indicating the potential of this novel technique in the application of soft tissue simulation

Image-Guided Robot-Assisted Techniques with Applications in Minimally Invasive Therapy and Cell Biology

There are several situations where tasks can be performed better robotically rather than manually. Among these are situations (a) where high accuracy and robustness are required, (b) where difficult or hazardous working conditions exist, and (c) where very large or very small motions or forces are involved. Recent advances in technology have resulted in smaller size robots with higher accuracy and reliability. As a result, robotics is fi nding more and more applications in Biomedical Engineering. Medical Robotics and Cell Micro-Manipulation are two of these applications involving interaction with delicate living organs at very di fferent scales.Availability of a wide range of imaging modalities from ultrasound and X-ray fluoroscopy to high magni cation optical microscopes, makes it possible to use imaging as a powerful means to guide and control robot manipulators. This thesis includes three parts focusing on three applications of Image-Guided Robotics in biomedical engineering, including: Vascular Catheterization: a robotic system was developed to insert a catheter through the vasculature and guide it to a desired point via visual servoing. The system provides shared control with the operator to perform a task semi-automatically or through master-slave control. The system provides control of a catheter tip with high accuracy while reducing X-ray exposure to the clinicians and providing a more ergonomic situation for the cardiologists. Cardiac Catheterization: a master-slave robotic system was developed to perform accurate control of a steerable catheter to touch and ablate faulty regions on the inner walls of a beating heart in order to treat arrhythmia. The system facilitates touching and making contact with a target point in a beating heart chamber through master-slave control with coordinated visual feedback. Live Neuron Micro-Manipulation: a microscope image-guided robotic system was developed to provide shared control over multiple micro-manipulators to touch cell membranes in order to perform patch clamp electrophysiology. Image-guided robot-assisted techniques with master-slave control were implemented for each case to provide shared control between a human operator and a robot. The results show increased accuracy and reduced operation time in all three cases