چكيده به لاتين
Proper Diagnosis of disease is one the most primary and important measures to treat it. Elastography is one of the latest methods of non-invasive diagnosis based on the mechanical properties of soft tissues. The most important and main advantage of this method is that it is non-invasive and it mostly identifies the condition of soft tissues of the body such as liver, breast, brain, prostate, muscles and tendons or finding a lesion and recognizing its type in those tissues.
By using the mechanical properties of a medium such as shear modulus and density, it is possible to study how a mechanical wave propagates in the desired medium and the velocity and amplitude of the wave can be calculated. The work done in the elastography is the opposite of this. In this study, by simulation in the COMSOL Multiphysics which is a Finite Element Analysis (FEA) software, a mechanical wave with a frequency of 200 Hz is created in the liver and tumor tissue as the studied medium. After creation of the mechanical excitation, a quasi-cylindrical shear wave in the medium propagates. using the finite element method, the displacement field is calculated over time in the liver and tumor. Then, with the help of the post processing of the displacement field in the MATLAB software as well as mechanical wave propagation relations in viscoelastic medium, the velocity and the wave attenuation of the propagated wave in the tissue as well as the shear storage and loss modulus of the tissue, which is part of its mechanical properties, are calculated. By comparing the mechanical properties of the patient's tissue with the mechanical properties of healthy tissue, we can judge about the condition of the tissue (for example, diagnosing the stage of fibrosis in the liver) or, if there is a lesion, the type of lesion, whether it is a cyst or malignant or benign tumor. Thus, a new non-invasive method has been developed for early detection of liver disease.
