The development of a virtual reality simulator for certain gastrointestinal endoscopic procedures

English: A Virtual Reality Gastrointestinal Trainer/Simulator has been developed to enable the simulation of gastrointestinal procedures on a personal computer (PC). Virtual Reality (VR) techniques are used in the construction of this computer-based system to enable the user to practice basic identification, navigational and therapeutical skills. The system consists of a computer-based simulator, a 3-dimensional (3-D) tracker, an endoscope/endocamera and a life-size gastrointestinal model. A normal endoscope/endocamera is used with a hollow transparent life-size gastrointestinal model to provide maximum realism. The computer-based simulator contains a virtual 3-D model of the relevant gastrointestinal organ. Currently the stomach, esophagus and entry to the duodenum (upper G.I. region) are focused on. The position and orientation of the front tip of the endoscope/endocamera are tracked with the 3-D tracker. This data is relayed to the computer, which then calculates and displays the appropriate image on the computer screen as realistically as possible. The calculated image closely resembles the image which would be seen with a real endoscope/endocamera in a real patient. The image is continually updated in accordance with the movement of the endoscope/endocamera and the properties of the gastrointestinal model. Some of the main problems that had to be addressed during the development of the system are: obtaining a 3-D computer graphic model of the stomach with the same shape, size, colour and texture as a real stomach; the simulation of abnormal conditions like ulcers, and how they can be placed inside the 3-D computer graphic model; the simulation of therapeutic tools, like biopsy foreceps; the implementation of realistic, but cheap force feedback; and the deforming of the 3-D computer graphic model when the user touches the inside of the stomach with the tip of the endoscope/endocamera. The system is ideal for teaching, training, simulation, patient briefings and research. In this thesis the virtual reality system, its development and operation is described in detail.