Developing a deformable model of liver tumor during breathing to improve targeting accuracy in image-guided therapy using finite element simulation

New advances in computer technology for biomechanical numerical modeling of human body are the basis for the improvement of targeting accuracy. This is especially important for guiding surgeons during interventional procedures and locating of liver tumor for radiotherapy. This paper deals with investigating the motion and deformation of a tumor, embedded into liver, during respiration. Here, a 3D FE model of human liver as a whole is developed to simulate liver behavior during respiration. First, the cloud of point according to CT image data was imported into CATIA software. Then a spherical tumor was embedded into the different segments of liver tissue in ABAQUS. A quasi-linear hyperviscoelastic constitutive model and an elastic behavior were used to define the liver and tumor properties, respectively. Boundary conditions were defined based on the difference between end-exhale and end-inhale states of liver tissue. Deformation and motion of liver tumor was then determined at intermediate states of breathing. Finally, the new position and the deformed shape of the tumor were investigated, considering the increase of tumor stiffness. The results show that if the tumor is located in the segment VII, then maximum displacement in the y-direction is observed.