State-of-the-Art and Future Prospects of Ion Beam Therapy: Physical and Radiobiological Aspects

The number of facilities offering radiotherapy with protons or heavier ions is continuously increasing; worldwide, more than 160 000 patients have been treated with protons, and more than 25 000 with heavier ions. Despite this substantial clinical experience, there is still a need for further developments and improvements which are specific to the properties of particle beams. This contribution briefly summarizes the main physical and radiobiological properties of ion beams which make them favorable for application in tumor therapy. In addition, major challenges that are currently addressed in different research areas are reviewed. These comprise the fields of biophysical modeling, treatment planning, mitigation of target motion and novel approaches based on particular spatio-temporal beam delivery techniques.