Analysis of the effect of sensor position and flexible endoscope to the haptic interface for simulation of gastrointestinal endoscopy

Abstract

Gastrointestinal endoscopy is a procedure that allows doctor to look inside of patient’s gastrointestinal tract which extends from mouth to anus through an endoscope for the purpose of diagnosis or treatment of disease. It is difficult for the novice doctors to be accustomed to the procedure because they have to navigate the endoscope with only force sensation on the hand and camera view of the tip of the endoscope based on their medical knowledge. Computer-based simulation of gastrointestinal endoscopy, one of the training methods for the procedure, has been researched and developed for several decades and consists of haptic and visual interface. The haptic interface has a role in providing force sensation to the trainee through the endo-scope. However, the previous haptic interfaces for this procedure still have limitations. This thesis ana-lyzes main causes of limitations of a haptic interface for simulation of gastrointestinal endoscopy to provide realistic haptic feedback by resolving the limitations of the previous haptic interfaces. Before that, required haptic feedbacks for simulation of gastrointestinal endoscopy are categorized and ana-lyzed by an interview and simulation to identify realistic haptic feedback. Studies about force information during gastrointestinal endoscopy are carried out. First, an inter-view is performed with medical doctor to represent their sensation of hand with mechanical terms. Next, several models of reflective forces are simulated and categorized by previous interview results. Finally, the experiments to determine the numerical values for models of reflective forces are performed with medical doctors. Characteristics of reflective forces during gastrointestinal endoscopy are analyzed. Two main causes of limitation of previous haptic interfaces are analyzed. One is position of the force sensor of the haptic interface and another is characteristics of the flexible endoscope. Force/torque sensor of the previous haptic interface is difficult to estimate rendered forces which are exerted to hand of the user because of the position of the sensor. This thesis analyzed the effect of the position of the sensor to the haptic interface for simulation of gastrointestinal endoscopy. Also, an en-doscope is bent in some condition during simulation of gastrointestinal endoscopy in the haptic inter-face because the endoscope is flexible. The effects of the flexible endoscope to the haptic interface are analyzed in this thesis.