Abstract
The amount of radiation delivered to normal tissues during radiotherapy can be reduced by predicting the respiratory motion of tumor tissues based on physical simulation. The diaphragm, which lies immediately below the lungs, is one of the main structures involved in respiratory motion and is an important boundary condition for lung deformation. For these reasons, it is important to estimate the motion of the diaphragm. We therefore propose a model of diaphragm motion based on anatomical knowledge. Since diaphragm motion is affected by ribcage movement, the interactions with ribcage movement are taken into consideration in the proposed model. Calculation is based on the shapes of the diaphragm and ribcage obtained from exhalation 3D CT images. The result of calculation in the inhalation phase is compared to the shape obtained from inhalation CT images to validate the model.
