Stiffness of a small tissue phantom measured by a tactile resonance sensor

Abstract

Many pathological conditions, for instance cancer, alter the elastic stiffness of tissues. Therefore, it is of interest to objectively quantify the stiffness of tissue samples. Tactile resonance sensor technology has been proven to measure the stiffness of tissues in a variety of medical applications. The technique is based on a vibrating piezoelectric sensor element that changes its resonance frequency when it is put in contact with a soft object to be measured. The frequency change is related to the mechanical properties of the soft object. This principle is implemented in an indentation setup where also the impression force and impression depth can be measured. The aim of this study was to investigate how the measured parameters of a tactile resonance sensor system depend on the limited size of a small gelatin tissue phantom sample. Indentation measurements were conducted on different locations on a small gelatin sample. Results showed that the force and frequency change were dependent of the measurement location and thus the sample geometry. The estimated stiffness was independent of the measurement location. Further studies must be conducted to determine the full value of the method for measuring the stiffness of small tissue samples. © 2010 International Federation for Medical and Biological Engineering.