Next-generation ion imaging: Towards an intergration into the treatment delivery system

• Applicants: Professor Dr. Oliver Jäkel; Dr. Mária Martisíková
• Subject Area: Medical Physics, Biomedical Technology
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 571723060

More than 2.7 million people in Europe are diagnosed with cancer each year, 50% of whom have an indication for radiotherapy. The overall prognosis has improved over the last decades thanks to technical developments. However, for some indications the prognosis remains poor. Especially the treatment of deep seated tumors with a high radiation resistance in close vicinity to critical organs such as brain stem or spinal cord remains a major clinical challenge. While devices for delivering focused therapies like ion beam radiotherapy are at a high level, our limited knowledge of composition and geometry of the patient’s tissue during the treatment remains a persisting issue. Current on-couch imaging methods are based on X-rays and are not sufficient for detecting ions’ range changes arising from such internal variations of patient’s tissue. Imaging of patients with the same kind of radiation as used in the treatment could minimize the uncertainties. This is technically particularly challenging for ion beam radiotherapy. Currently, no commercial ion beam imagers certified for clinical use exist yet. A major obstacle is a lack of viable solutions for implementing such imaging approaches into the clinical environment without disturbing the treatment process. Hence, a fundamentally different approach is needed. We propose to develop a unique ion-imaging system, by integrating one part of the imager directly into the ion beam monitor of the ion accelerator, while the second part—a compact and mobile device—will be located exclusively behind the treated patient, and thus not disturbing the treatment in any way. The imager would enable to perform quantitative ion-beam radiography on-couch, before each treatment with minimal radiation dose. The targeted image parameters fulfill the clinical needs concerning the precision, imaging dose and speed. The imager will be optimized for helium-beam imaging, and its usability for protons will be investigated. The project is going to be developed by an experienced, highly interdisciplinary team of accelerator and detector physicists, physicians and engineers. First, the individual imager parts will be built, based on complementary state-of-the-art detection technologies from particle physics research: scintillating fiber mats and silicon pixel detectors. Subsequently, both ion beam imager parts will be combined with the ion beam delivery system, forming one imaging unit. The synchronized operation of all components and the handling of high data rates are crucial here. Dedicated image reconstruction algorithms will be developed. Finally, the performance of the method will be accessed under clinical conditions for helium-ion and proton beams. If successful, this innovative patient imaging method will facilitate unique clinical studies on reducing the irradiation of sensitive structures close to the tumor. In particular, radiotherapy of skull base, spine and head and neck tumors can benefit from this new imaging modality.

• DFG Programme: Research Grants
• Co-Investigators: Dr. Tim Gehrke; Privatdozent Semi Harrabi, Ph.D.