An indentation-type instrument for measuring soft tissue elasticity

Abstract

An indentation-type instrument was presented in this study for measuring soft tissue elasticity and for further applications in finite element modeling and simulation of soft organs. The instrument consists of a stepping motor, an elongated probe, a sphere at the end of the probe, a load-cell fixed inside the probe, and a frame base. Indentation experiments were firstly performed on samples made of artificial muscle material and elasticity was estimated through curve fitting. The estimated elasticity was compared with the value measured by Instron material testing machine and good agreement was achieved. The instrument was then used to measure the elasticities of bovine and chicken livers and results suggested that the extended contact theory with two parameters is necessary to obtain a precise approximation of the liver behaviors. Finally, the device was applied to identify embedded hard objects within a soft medium for mimicking hard tumor inside soft tissue scenario.