Overview of recent advances in treatment planning for ion beam radiotherapy Michael Krämer, Emanuele Scifoni, Frederike Schmitz, Olga Sokol and Marco Durante Eur. Phys. J. D, 68 10 (2014) 306 Published online: 21 October 2014 DOI: 10.1140/epjd/e2014-40843-x