Abstract
In current standard radiotherapy of lung cancer, an excessive volume of normal tissues may be irradiated due to respiratory displacement. If the motion of the lungs could be predicted by computer simulation, radiation exposure to normal tissues could be reduced. Lung deformation is modeled as an elastic material. The lung model is created automatically from computed tomography (CT) images using binarization, mathematical morphology, and region growing. The effects of abdominal breathing and pleural sliding are incorporated into the boundary conditions by template matching between CT images acquired during the inhalation and exhalation phases. Lung motion is then predicted using the moving particle simulation (MPS) method. Since CT images are required for radiotherapy planning, we propose a generation method for simulation-based 4DCT equivalent to actual 4DCT using CT images acquired during the inhalation and exhalation phases and particle simulation results obtained using the image warping technique.
