Research on tumor therapy with oxygen ions: GSI doctoral candidate is honored
Clinical and radiobiological studies for tumor therapy with heavy ions began at GSI over 20 years ago. Today the objective of such research at GSI and FAIR is to continue improving this successful therapy and to use it in increasingly customized ways in medical applications. One of the researchers with this objective is Dr. Olga Sokol, a scientist in the Biophysics Department at GSI. One of the focuses of her research is the use of oxygen ions in tumor treatment. This was the main thrust of her doctoral dissertation, for which she was recently honored with the Giersch Award for outstanding doctoral dissertations in 2018.
Ion beam therapy is a rapidly developing branch of tumor therapy. Because ions release the largest proportion of their energy at the end of their range, they are good candidates for the effective treatment of deep-seated tumors. In addition, they make it possible to efficiently spare the healthy tissue surrounding the tumor. The tumor therapy with accelerated carbon ions that was developed at GSI is now being used in clinical procedures on a broad scale at institutions including the Heidelberg Ion-Beam Therapy Center (HIT). In current research, scientists are looking to find out which kinds of heavy ions — such as carbon, oxygen or helium ions — are the most effective for specific tumor diseases. For some types of tumors the most effective ions have already been clearly demonstrated; for others, further physical and radiobiological studies are necessary.
This is the area where Sokol is doing her research. Her dissertation, “Oxygen ions as a single and combined modality in radiotherapy,” at the Physics Department of Technische Universität Darmstadt was based on an experimental investigation of the relevant properties of oxygen (16O) ions and an analysis of the possibility of introducing them into clinical practice mainly for the treatment of hypoxic tumors. Many tumors have a poor blood supply and therefore have an oxygen concentration that is lower than normal — a condition known as hypoxia. As a result of their lack of oxygen, these tumors respond poorly to radiotherapy and chemotherapy as well as being predisposed to metastases. In such cases, treatment with oxygen ions could bring progress, due to their specific physical properties, namely an increased linear energy transfer. Sokol’s dissertation presents the first comprehensive description and experimental characterization of oxygen-16 ions from the standpoints of physics and radiation biology, as well as the subsequent treatment planning studies. She carried out this work at GSI and HIT.
Sokol was able to provide the first experimental demonstration that oxygen ions could be more effective than carbon ions in treatments of certain cases of hypoxic tumors. Her comparison of radiotherapy plans with oxygen and with lighter ion beams showed that the use of oxygen ions for hypoxic tumors resulted in optimally uniform target recognition and also in certain cases might lead to the reduction of the radiation damage to normal tissue and critical organs. The recommended use of a tumor therapy with oxygen ions could thus improve therapeutic success for some cases of hypoxic tumors. Dr. Sokol’s dissertation was supported and assessed by Professor Marco Durante, Director of the Biophysics Department at GSI, and Professor Thomas Aumann, head of the Nuclear Reactions Research Division at GSI. (BP)