Dynamic touch-enabled virtual palpation

Palpation is an important method of feeling with hands during a physical examination, in which the doctor presses on the surface of the patient body to feel the organs or tissues underneath. In current surgical simulation systems, the lack of an effective sense of touch is still a major problem. In this paper, a dynamic touch-enabled virtual palpation model is proposed. The palpation force sensing between the index finger and virtual tissues is simulated through a body-based haptic interaction model. Both contact and frictional forces are evaluated based on Hertz’s contact theory, and the press distribution within the contact area is also specified. The non-linear viscoelastic behavior of typical tissues is mimicked via a volumetric tetrahedral mass-spring system. Reaction during the palpation is restricted to a local area to highly reduce the order of the dynamic equation of the entire system to guarantee a fast working rate. Mechanical tests have been performed to evaluate the palpation force perception and the realistic behavior of typical human tissues. Copyright# 2007 JohnWiley & Sons, Ltd.