Ion-Beam Therapy Related Applications


Cancer is one of the most severe health problems throughout the population and its incidence is steadily growing. In Germany, about every second cancer patient is treated with radiotherapy. Photons are most commonly used, but also proton or ion-beam (typically 12C) radiotherapy is growing in popularity [1]. Even if proton and 12C-ion therapy are technically complex compared to the standard photon therapy methods, there are still clinical cases where the dose conformity of modern photon therapy techniques is not sufficient, e.g. brain tumours or pediatric patients. Proton or ion beams can achieve better dose conformity than high-energy photons due to the underlying radiation physics and other additional advantages due to radiobiological effects.

Because of these advantages, proton and ion-beam therapy is a rapidly growing therapy modality. Meanwhile more than 110 therapy centers are world wide in operation and 30 further facilities are under construction.

One particular technological innovation in the middle of the 1990s had a decisive impact on proton and heavy-ion therapy in their present form: “Pencil beam scanning” or “Raster scanning” [4]. While developments of this technique were taking place at the Paul Scherrer Institute (PSI) with protons, the same was done at GSI with 12C ions [5]. Instead of the passive broadening of the beam with scatter foils and collimators as it was practised until then, the new technique employs a sharp pencil beam that is scanned over the irradiation volume using adjustable magnetic detection in the vertical and horizontal direction and active variation of the beam energy by the synchrotron (raster scanning). This improves significantly the conformity of the dose distributions and reduces the secondary neutron dose to the patients as compared with the passive techniques [6]. In 1997, the first patient was treated with a scanned 12C ion beam at GSI [7], followed by another 439 over 11 years of a pilot project. Nowadays, clinical treatments are performed at the Heidelberger Ionenstrahl-Therapiezentrum (HIT), while heavy-ion therapy research is carried on at GSI. The raster scanning technology became meanwhile the technical standard in proton and ion-beam therapy.

Pictures of carbon-ion beam therapy (in the last 70 years)

1: First treated patient at Lawrence Berkeley Laboratory (1954)
[figure from P. Morel, MSPT: Motion Simulator for Proton Therapy (2014)]
2: Cancer patients were treated at the Bevalac (1975-1993) with the help of a plastic head positioner and beam compensator
[figure from]
3: The ion-beam therapy (at that time rather called ‘heavy-ion therapy’) and beam-scanning pilot project at GSI, Cave M (1997-2008)[figure from ]
4: The Heidelberg ion-beam therapy facility (since 2009), in the gantry treatment room (the world first 360° rotatable ion-beam line with scanning)
[figure from
5: Treatment room in the Marburg ion-beam therapy facility MIT (since 2015), one robot for positioning of the treatment table with patient,  a second robot for the X-ray imager [figure from]


[1] Durante et al, Charged-particle therapy in cancer, Nat. Rev. Clin. Oncol. (2017), 
[2] Horst, Measurement of Nuclear Reaction Cross Sections for Applications in Radiotherapy with Protons, Helium and Carbon Ions (2020),
[3] Levin et al, Proton Beam Therapy, Br. J. Cancer (2005)
[4] Kraft et al, Tumor therapy with heavy charged particles, Progr. Part. Nucl. Phys. (2000),
[5] Haberer et al., Nucl. Instrum. Methods Phys. Res. A (1993)]
[6] Hall, Int. J. Radiat. Oncol. Biol. Phys. (2006)
[7] Schardt et al, Heavy-ion tumor therapy: Physical and radiobiological benefits, Rev. Mod. Phys. (2010),