A real-time graphic environment for a urological operation training simulator (original) (raw)
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Development of a real-time visual and force environment for a haptic medical training simulator
2008
Abstract In this article, a real-time, visual and force environment for a 5-dof haptic urological training simulator is presented that deals with a low-force, high-deformation environment. A real-time graphical representation of the male urethra during the insertion of an endoscope is developed. Smooth urethra deformations are produced by a mesh of piece-wise Bézier interpolations, while its inner wall is simulated by realistic tissue textures. Efficient real-time techniques are developed that introduce endoscope camera depth-of-field effects.
Design and implementation of a haptic device for training in urological operations
2003
Abstract Virtual reality is becoming very important for training medical surgeons in various operations. Interfacing users with a virtual training environment requires the existence of a properly designed haptic device. This paper presents the design and implementation of a new force feedback haptic mechanism with five active degrees of freedom (DOFs), which is used as part of a training simulator for urological operations.
A Virtual Graphical and Haptic Environment for a Medical Training Simulator
2009
Abstract An enhanced real-time virtual graphical and haptic environment used in a medical training simulator is presented in this paper. The medical simulator is a training simulator for urological minimally invasive operations, and consists of a five-dof haptic device, the virtual graphical and force environment, and the control system. All parts of the simulator are described in detail. A real-time graphical representation of the male urethra during the insertion of an endoscope is developed.
Design of a 5-dof haptic simulator for urological operations
2002
Abstract A haptic feedback mechanism with five active degrees of freedom (dof), part of a training simulator for urological operations, is presented. The mechanism consists of a 2-dof 5-bar linkage, and a 3-dof spherical joint. To reproduce very small forces and moments, the mechanism has low friction, inertia and mass, is statically balanced, and has a simple mass matrix. Roll-pitch-yaw motions of the tool result in motions of the corresponding actuator. Force feedback transmission is achieved via capstan drives and idler pulleys.
—We have developed a computer-based training system to simulate laparoscopic procedures in virtual environments (VEs) for medical training. The major hardware components of our system include a computer monitor to display visual interactions between three–dimensional (3-D) virtual models of organs and instruments together with a pair of force feedback devices interfaced with laparoscopic instruments to simulate haptic interactions. In order to demonstrate the practical utility of the training system, we have chosen to simulate a surgical procedure that involves inserting a catheter into the cystic duct using a pair of laparoscopic forceps. This procedure is performed during laparoscopic cholecystectomy (gallbladder removal) to search for gallstones in the common bile duct. Using the proposed system, the user can be trained to grasp and insert a flexible and freely moving catheter into the deformable cystic duct in virtual environments. As the catheter and the duct are manipulated via simulated laparoscopic forceps, the associated deformations are displayed on the computer screen and the reaction forces are fed back to the user through the force feedback devices. A hybrid modeling approach was developed to simulate the real-time visual and haptic interactions that take place between the forceps and the catheter, as well as the duct; and between the catheter and the duct. This approach combines a finite element model and a particle model to simulate the flexible dynamics of the duct and the catheter, respectively. To simulate the deformable dynamics of the duct in real-time using finite element procedures, a modal analysis approach was implemented such that only the most significant vibration modes of the duct were selected to compute the deformations and the interaction forces. The catheter was modeled using a set of virtual particles that were uniformly distributed along the centerline of catheter and connected to each other via linear and torsional springs and damping elements. In order to convey to the user a sense of touching and manipulating deformable objects through force feedback devices, two haptic interaction techniques that we have developed before were employed. The interactions between the particles of the catheter and the duct were simulated using a point-based haptic interaction technique. The interactions between the forceps and the duct as well as the catheter were simulated using the ray-based haptic interaction technique where the laparoscopic forceps were modeled as connected line segments.
Experimental tissue parameter identification for use in endoscopic urological haptic simulators
2009
Abstract A method is developed for obtaining parameters for tube-like soft-tissues, to be used in urological haptic simulators. A device was designed and built that allows the acquisition of forces and displacements during endoscope insertion in a tube-like soft tissue. The device consists of a mechatronic ball screw mechanism, with a 6 DOF force/torque sensor attached to it.
Graphic and haptic simulation system for virtual laparoscopic rectum surgery
The International Journal of Medical Robotics and Computer Assisted Surgery, 2011
Medical simulators with vision and haptic feedback techniques offer a cost-effective and efficient alternative to the traditional medical trainings. They have been used to train doctors in many specialties of medicine, allowing tasks to be practised in a safe and repetitive manner. This paper describes a virtual-reality (VR) system which will help to influence surgeons' learning curves in the technically challenging field of laparoscopic surgery of the rectum. Data from MRI of the rectum and real operation videos are used to construct the virtual models. A haptic force filter based on radial basis functions is designed to offer realistic and smooth force feedback. To handle collision detection efficiently, a hybrid model is presented to compute the deformation of intestines. Finally, a real-time cutting technique based on mesh is employed to represent the incision operation. Despite numerous research efforts, fast and realistic solutions of soft tissues with large deformation, such as intestines, prove extremely challenging. This paper introduces our latest contribution to this endeavour. With this system, the user can haptically operate with the virtual rectum and simultaneously watch the soft tissue deformation. Our system has been tested by colorectal surgeons who believe that the simulated tactile and visual feedbacks are realistic. It could replace the traditional training process and effectively transfer surgical skills to novices.
Graphic and haptic simulation for transvaginal cholecystectomy training in NOTES
Journal of biomedical informatics, 2016
Natural Orifice Transluminal Endoscopic Surgery (NOTES) provides an emerging surgical technique which usually needs a long learning curve for surgeons. Virtual reality (VR) medical simulators with vision and haptic feedback can usually offer an efficient and cost-effective alternative without risk to the traditional training approaches. Under this motivation, we developed the first virtual reality simulator for transvaginal cholecystectomy in NOTES (VTEST™). This VR-based surgical simulator aims to simulate the hybrid NOTES of cholecystectomy. We use a 6DOF haptic device and a tracking sensor to construct the core hardware component of simulator. For software, an innovative approach based on the inner-spheres is presented to deform the organs in real time. To handle the frequent collision between soft tissue and surgical instruments, an adaptive collision detection method based on GPU is designed and implemented. To give a realistic visual performance of gallbladder fat tissue remov...