Numerical simulation of the influence of the elastic modulus of a tumor on laser-induced ultrasonics in soft tissue.

The influence of the elastic modulus of a tumor (EMT) on the laser-generated thermoelastic force source and ultrasound waves are investigated by using the finite element method. Taking into account the effects of thermal diffusion, optical penetration, and finite duration of laser pulse, the transient temperature distribution is obtained. Applying this temperature field to structure analyses as thermal loading, the thermoelastic stress field and laser-induced ultrasound wave in soft tissues are obtained. The results show that there is a linear correlation between the maximum compressive stress and the elastic modulus of tissues. It is also shown that the features and frequency regions of the laser-induced ultrasound waveform have a close relationship with the EMT, which has been further verified by a corresponding experiment.