Biomedical subjects

T Kesavadas

Publications and source records attributed to T Kesavadas.

10 recordsLinked to original sources

PubMed2006

Parametric modeling and simulation of trocar insertion.

Trocar insertion, the first step to most micro surgery procedures is a difficult procedure to learn and practice because procedure is carried out almost entirely without any visual feedback of the organs underlying the tissue being punctured. A majority of injuries is attributed to the excessive use of force by the surgeon. This paper looks at developing a haptic based trocar insertion simulator which will assist in training and skill advancement in carrying out this procedure. Different issues regarding development of force model and and trocar-tissue interaction is studied.

Computer Simulation↗

PubMed2005

3D Real-time FEM based guide wire simulator with force feedback.

Minimally invasive surgical techniques using catheter is now used in many procedures. Development of surgical training of such procedures requires real-time simulation of tool-organ interaction. In such processes, each subsequent step of interaction would be based on the current configuration of the surgical tool (guidewire in this case), leading to development of techniques to solve and visualize the configuration of tool at every time step. This paper presents a Finite Element (FEM) based approach to simulate the tool-organ interaction.

Catheterization↗

PubMed2005

The haptic kymograph: a diagnostic tele-haptic device for sensation of vital signs.

The kymograph is device for measuring and presenting pressure-based signals, such as human heart beat and artery volume pressure. The Haptic Kymograph is a haptically-enhanced tele-medicine system which is used to acquire human vital signs and then to transform these signs into sensible, scalable and ubiquitous media so that a user can easily comprehend subtle and ambiguous signals in a remote place. In an experiment setup a patient's artery pressure pulse was captured at 200 Hz of sampling rate, transmitted via TCP/IP network, and replicated in a remote place using a PHANToM haptic device coupled with a real-time visual interface. In this paper we report our recent progresses in developing a low-cost input system, network interfaces and haptic replication of the human artery volume pulse signal.

Blood Pressure↗

PubMed2005

Development of a method for surface and subsurface modeling using force and position sensors.

Subsurface modeling of deformable objects, such as soft tissues and organs, involves the use of non-destructive methods of determining the properties of an object encased by a material. Some of the properties that can be determined from subsurface modeling include: shape, hardness, texture and possibly material. The ability to determine these properties is based on the accuracy of the method used and the properties of the surface encasing the object. As computers become more powerful and are able to produce even more realistic graphics, it will be possible to store and re-create precise duplicates of the original for later analysis. This paper will present a method of approximately modeling both the surface and an object below the surface of the skin by a method of palpation and then present this data in an interactive 3-D model.

Computer Simulation↗

PubMed2004

Real-time volume haptic rendering of non-linear viscoelastic behavior of soft tissue through dynamic atomic unit approach.

The aim of computer haptics is to enable the user to touch, feel and maneuver virtual objects using a haptic interface. As the user "feels" the virtual object by applying force through the interface, complex calculations have to be done in real-time to generate a feedback force appropriate to the material properties of the object being "touched". In this paper we propose a method for modeling soft bodies, which incorporate non-linear, viscoelastic, anisotropic behavior that will enable real-time user interaction and still satisfy the high force-feedback frequency requirements. In this paper, we restrict the user interaction with virtual objects to palpation.

Connective Tissue↗

PubMed2004

A prototype virtual reality system for preoperative planning of neuro-endovascular interventions.

This paper describes our efforts at creating a system with real time acquisition and geometric processing of the patients vascular anatomy, supplemented by a framework to simulate catheter vasculature interaction. Our system uses biplane angiograms coupled with an algorithm for generation of 3D vascular trees for patient data acquisition. Surface reconstruction and processing of this data is performed to provide novel decision aids to the interventionalist. The processed data can be loaded in a virtual environment to simulate guidance of the catheter through the patient's vasculature. With our combination of techniques, a patient specific visualization and simulation environment can be prepared within the narrow time window available for this procedure.

Algorithms↗

PubMed2003

Utilization of virtual reality for endotracheal intubation training.

Tracheal intubation is performed for urgent airway control in injured patients. Current methods of training include working on cadavers and manikins, which lack the realism of a living human being. Work in this field has been limited due to the complex nature of simulating in real-time, the interactive forces and deformations which occur during an actual patient intubation. This study addressed the issue of intubation training in an attempt to bridge the gap between actual and virtual patient scenarios. The haptic device along with the real-time performance of the simulator give it both visual and physical realism. The three-dimensional viewing and interaction available through virtual reality make it possible for physicians, pre-hospital personnel and students to practice many endotracheal intubations without ever touching a patient. The ability for a medical professional to practice a procedure multiple times prior to performing it on a patient will both enhance the skill of the individual while reducing the risk to the patient.

Emergency Medicine↗

PubMed2003

Development of an interactive teaching system based on motion synchrony between physical and virtual models.

In advancing our capabilities in the realm of virtual reality, the development of haptic technology has been a rate-limiting factor in producing tactile sensations directly onto the human hands. The Living Anatomy Program seeks to obviate the need for such technology by designing physical objects based on anatomic components that feel realistic to the touch. Furthermore, synchronizing motion between physical and related virtual objects infinitely expands visual design options and provides a profound level of immersion into content.

Computer Simulation↗

PubMed2002

A virtual environment for esophageal intubation training.

Esophageal intubations are performed for urgent airway control in injured patients. Current methods of training include working on cadavers and mannequins, which lack the realism of a living human being. Work in this field has been limited due to the complex nature of simulating in real-time the interactive forces and deformations which occur during an actual patient intubation. This study addressed the issue of intubation training in an attempt to bridge the gap between actual and virtual patient scenarios. The two haptic devices along with the real-time performance of the simulator give it both visual and physical realism. The three dimensional viewing and interaction available through virtual reality make it possible for physicians, pre-hospital personnel and students to practice many esophageal intubations without ever touching a patient. The ability for a medical professional to practice a procedure multiple times prior to performing it on a patient will both enhance the skill of the individual while reducing the risk to the patient.

Computer Simulation↗

PubMed2000

Material property determination of sub-surface objects in a viscoelastic environment.

Modeling human organs and soft tissue or anatomic regions for the purpose of medical training and simulation is a relatively new area. The data presented here is the groundwork for our ongoing development of a real-time haptic virtual environment for abdominal soft tissue palpation. The purpose of modeling the human abdomen is twofold. First, to provide a mathematical description of soft tissue and organs and second, to simulate the behavior of realistic interactions in real-time within a virtual environment. We have developed a, non-invasive, system that will allow us to determine mathematical functions that model the deformation of individual layers of soft tissue within the human abdomen. This system has been tested, experimentally, with a viscoelastic polyester foam model. We have been able to determine the stiffness and force/displacement function of an object beneath two layers of foam having different material characteristics. These experimental results correlate well with known polyester foam material characteristics. In general, the calculated stiffness constants were within 5% of the actual value. The data presented in this study shows that this system may be a viable tool for accurate measurement of human soft tissue properties and behavioral response to palpation.

Abdomen↗