An Evaluation Method for Real-Time Soft-Tissue Model Used for Multi-Vertex Palpation

Soft tissue palpation plays an important role in diagnosing various diseases. Palpating skills are tedious to learn due to the difficulty of describing the sense of touch. Because of its interactive nature, a virtual reality (VR) training system embedding with real-time soft-tissue models may be helpful to teach such skills to medical residents. Studies show that such a VR system impacts human perception during palpating at various levels, largely due to the real-time models. Therefore, we propose a formal method for evaluating real-time models considering the human perception. Based upon surface (multi-vertex) contact with 4 force distributions, the evaluation compared a real-time model with a Finite Element Method (FEM) model featuring physical parameters. The comparison consisted of two statistical approaches - ANOVA and Bland and Altman agreement-to assess both visual displacement and force feedback. A case study demonstrated the advantages provided by this evaluation method.