In a worldwide effort in research and development, radiation therapy with carbon ions has evolved to a technologically challenging but clinically very promising treatment option for cancer patients. To further improve patient benefit, optimal use of the physical and biological characteristics of carbon ions as well as of the available technologies should be made.The present thesis investigates the impact of different beam delivery systems and radiobiological models on the quality of treatment plans in carbon ion radiotherapy. The results of the study may provide pointers as to the role and the possible future implementation of the different techniques and radiobiological models in existing and upcoming particle therapy centers.