Real-time fluoroscopy simulation of common bile duct stone extraction

Abstract

Endoscopic retrograde cholangiopancreatography (ERCP) is not only used in diagnosis of bile duct and pancreatic duct; now a days, it is also a front line treatment procedure for choledocholithiasis (gallstone in com-mon bile duct) by combining with endoscopic sphincterotomy (ES). Still, it is a very challenging procedure for inexperienced doctors and requires a lot of practice (around 200) to be skilled enough to perform real surgery. Stone extraction from the common bile duct without damaging the duct is one of the most difficult parts of ERCP. For this circumstance, this thesis aims to develop a training simulation of common bile duct stone extrac-tion procedure which contains the real-time fluoroscopy simulation of deformable bile duct model and the inter-action model of duct and stone/ balloon, and duct and catheter.This thesis focuses on real-time deformation of bile duct, interaction between catheter and duct, interac-tion between stone and duct, and fluoroscopy visualization of the overall procedure. Simulation models are de-veloped by considering the characteristics of real model. The common bile duct has a very special deformation behavior. Upper part of the duct is attached with liver and gallbladder and lower part is attached with major papilla. The whole duct has some global movement due to the respiratory motion. Beside this, the upper part acts as a rigid body with some local deformation in the duct wall and the lower part shows some global deformation along with the local deformation due to the exertion force by catheter in the time of stone or balloon extraction. To represent these three different deformation characteristics, a centerline based modeling method is proposed to model the duct which has a set of circular points for every center points. Where, all the center points of the duct are connected with axial spring-damper model and sinusoidal force is applied to represent the respiratory motion. In the lower part, there is additional bend...