A Position-Based Dynamics Simulation of Liver Deformation with Ellipsoidal Particles

Virtual liver tumor resection surgery is widely used for training physicians in surgical skills. Establishing a realistic liver deformation model is an important prerequisite for virtual surgery. In this study, we propose a position-based dynamics model using ellipsoidal particles for liver deformation simulation to overcome the low computational efficiency of traditional voxel-sampled position-based dynamics model. Specifically, we segmented the liver and reconstructed its 3D model from medical computed tomography images. Next, we generated ellipsoidal particles at the grid vertices based on center distance constraints. Finally, liver deformation was simulated by solving the shape matching constraints between the particles. The results of simulation experiments showed that our proposed method achieved similar deformation authenticity and reduced computational time compared to the traditionally used voxel-filled particles model. The frame rate of our proposed method achieved 201 frames per second, which satisfies the basic frame rate requirements for real-time display.