Dietrich Harder Master’s Thesis Award 2025

The Dietrich Harder Master's Thesis Award 2025 goes to Robin Erdmann

Robin Erdmann has won the Dietrich Harder Master's Thesis Award. The prize, sponsored by PTW, was awarded at the DGMP Annual Meeting, held in Berlin this September. It recognizes outstanding scientific achievements of master's graduates in the field of medical radiation physics.

Robin Erdmann impressed the jury with his master's thesis entitled “Radiochemical Simulations with Consideration of Interaction Potentials”. His work contributes to deciphering the chemical phase of the efficacy of ionizing radiation — a crucial stage between physical energy absorption and biological damage — and making it calculable. The idea for this master's thesis originated at the Institute of Medical Physics in Giessen in the research group led by Prof. Dr. Kilian Baumann. Robin Erdmann had already used Monte Carlo simulations in his bachelor's thesis to explore previously unconsidered aspects.

Robin Erdmann receives the Dietrich Harder Master's Thesis Award during the DGMP Annual Meeting in Berlin. From left to right: Prof. Dr. Markus Buchgeister, Rüdiger Lauk, Robin Erdmann, Prof. Dr. Christopher Bert, Prof. Dr. Andrea Denker. Photo: ©2025 Claudia Last | dias.fotografie

Intermolecular interactions in diffusion and reaction

Erdmann’s master's thesis focuses on refining Monte Carlo simulation models at the cellular level—specifically, radiobiological simulations that enable the prediction of indirect DNA damage of ionizing radiation. Until now, intermolecular interactions between chemical particles have not been considered in simulations of these processes, which take place in smallest fractions of a second. To simulate the chemical stage, it is necessary to model both diffusion and reaction of the involved chemical particles. By incorporating the intermolecular forces into the model, it is possible to refine the simulation of the chemical stage and, in particular, the indirect effects of radiation. This is especially relevant for high-LET and FLASH radiation, where large numbers of reactive radicals are concentrated in a confined space within extremely short timeframes.

For those who want to delve deeper into the topic

The algorithmic implementation of Erdmann’s refined diffusion and reaction model enables the analysis of its impact on the temporal development of G values. G values indicate how many species are produced per 100 eV of deposited energy. Since electrostatic interactions have a significant influence on radiochemical yields, they are essential for accurate modeling of the chemical phase.

What’s next?

With the model now refined, its effects will be experimentally validated in follow-up projects. The application of this model to oxygen systems demonstrates how effects resulting from interactions can be specifically amplified and thus made more accessible experimentally. Robin Erdmann continues his research on this topic as part of his doctoral studies.

The award winner studied medical physics at the Technical University of Central Hesse, where he also completed his master's thesis and is currently pursuing his PhD.

The PTW-sponsored award for an outstanding poster in the field of medical dosimetry or radiation physics was presented this year to Florian Katsch for his poster entitled “Monte Carlo Analysis of the Depth-Dependent Dose Response of a Si Diode (IBA RAZOR^TM) Compared to an Ionization Chamber (Type 34001 PTW Roos^®) in Clinical Electron Dosimetry.”