Radiotherapy is one of the main treatments for cancer, and a multi-disciplinary field of research, mostly involving medicine, physics and mathematics. The focus of this thesis lies in improvements for the treatment planning, which is a multi-criteria process. We have been constructing a new method to form the Pareto front for certain objectives. For a Pareto optimal plan one objective cannot be improved without worsening another objective. The main question is with which plan the patient should be treated. To compare treatments we have developed a new method to look at other optimal solutions on the Pareto front around a given solution. This is done by quickly using of the reference point method. The main advantage is that, when a clinical isn’t pleased enough with a certain objective in a given solution, it is possible the optimize that objective some more.