Prof. Dr. rer. nat. Björn Poppe
Medical Radiation Physics
Department for Medical Physics and Acoustics
School of Medicine and Health Sciences
Carl von Ossietzky University Oldenburg

Assoc. Prof. Dr. rer. nat. Antje C. Knopf
Department of Radiation Oncology
University Medical Center Groningen (UMCG)

Prof. Dr. Johannes Albertus Langendijk
University Medical Center Groningen (UMCG)

Leonie Brodbek, M.Sc.
PhD Student

Jana Kretschmer, M.Sc.
PhD Student

Summary: Compared to conventional radiation therapy with high energy photon beams, proton therapy offers several clinical advantages in terms of dose conformity and biological effectiveness. Therefore, it is a more rational modality to treat certain cancers such as childhood tumours or primary and metastatic lesions situated near critical organs at risk, for example the spine or the brain stem. Due to the inherent complexity of the treatment plans of proton therapy, which is made up of hundreds of distinct energy-modulated pencil beams scanned throughout the tumour volume, a comprehensive quality assurance (QA) program must be integrated into the treatment workflow to safeguard the whole irradiation process. The proton therapy facility in UMCG will begin its clinical use early 2018. Currently, a log-file-based QA-workflow is being devised in UMCG. The aim of this proposed project is to develop a measurement-based validation workflow that is used on one hand to independently assess the performance of the proton beam delivery system at the UMCG and on the other hand to serve as a validation of the UMCG’s computational-based QA-workflow using a Monte-Carlo dose engine. Both the research groups in Oldenburg and Groningen have extensive experience in multidimensional dose measurements for photon beams. The expertise areas of both groups cover from detector developments to signal theoretical analysis, which will be translated in this project into the field of proton therapy. The results of this research will directly serve to improve the quality of the proton treatments in UMCG to guarantee the beneficial clinical outcome to all patients. This unique cross-border clinical and scientific cooperation will also serve to foster the sharing and development of research infrastructure and expertise between Groningen and Oldenburg.

Publications:

• Kretschmer, J., Dulkys, A., Brodbek, L., Stelljes, T. S., Looe, H. K., & Poppe, B. (2020). Monte Carlo simulated beam quality and perturbation correction factors for ionization chambers in monoenergetic proton beams. Medical physics, 47(11), 5890–5905.
• Brodbek, L., Kretschmer, J., Willborn, K., Meijers, A., Both, S., Langendijk, J. A., Knopf, A. C., Looe, H. K., & Poppe, B. (2020). Analysis of the applicability of two-dimensional detector arrays in terms of sampling rate and detector size to verify scanned intensity-modulated proton therapy plans. Medical physics, 47(9), 4589–4601.