Review of Scientific Instruments,78(11): pp. 115101-1-6.We have experimentally investigated the depth sensitivity limit of a piezoelectric cantilever tissue
elastic modulus sensor and simultaneously determined the elastic modulus and the depth of a tumor
directly. Using model tissues consisting of bottom-supported modeling clay inclusions of various
depths in a gelatin matrix, we empirically determined that the depth sensitivity limit of a
piezoelectric cantilever sensor was twice the linear dimension of the indentation area or the
cantilever width . Knowing the depth sensitivity limit of the individual cantilever sensor as input
and treating a model tissue that has the gelatin matrix on top and the modeling clay inclusion at the
bottom as two springs in series, we showed that the elastic moduli and depths of the hard inclusions
could be simultaneously determined with the elastic modulus profiles measured by two cantilevers
with different widths as input
