Collision detection method for interactive simulation of coil embolization procedure

Abstract

Coil embolization is medical procedure that makes occlusion at the aneurysm site with catheters and platinum coils. In this medical procedure, coil deployment step is very hard to perform because of several complications that are critical to patients. In this circumstance, physics-based interactive simulation of coil deployment procedure not only can help the doctor as planning of the procedure but also be used as training for the novice. To develop the interactive simulation of coil deployment procedure, virtual models and interaction between the models should be realized and should be operated in real-time. However, it’s hard to handle numerous contact points in real-time. This thesis is focus on the collision detection method for a real-time physics-based simulation of coil deployment procedure. Firstly, simulation models are developed by considering properties of real model. The aneurysm model is regarded as a rigid body and it only contains geometric information. Mass-spring model is utilized for the coil model with simplified transformation matrix. An algorithm for solving the tri-diagonal matrix is modified which can accomplish globalization and LU factorization in one loop. As a result, modified algorithm can solve the dynamic equation with less computation time. Second, collision detection method that combines BVH method and spatial hashing method is proposed to detect the numerous contact points properly. Actually, BVH method is appropriate method to detect the collision between the aneurysm model and the coil model while the spatial hashing method is efficient at detecting the collision between coil models. Two collision types are introduced corresponding to the collision detection method. Type 1 collision is simplified with assumption that aneurysm model is rigid and has convex shape. Moreover, modified method that enlarges the BVH in pre-computation stage can further reduce the computational load. In type 2 collision, the method to assign the...