In order to develop new approaches in radiation therapy, experiments on animals, mostly mice, are necessary. The group "Preclinical imaging for Radiooncology" specializes in investigating laboratory animals with innovative imaging techniques. These preclinical modalities are similar to the modern methods used in humans. However, thea were specially adapted to fit the needs in small animals (e.g. micro-CT, small animal PET/MRI, small animal ultrasound and optical imaging).
The effect of radiation on tumors can be verified in animal experiments with different methods. One standard method is to transplant human tumor tissue (e.g. from lung or brain tumors) subcutaneously, i.e. under the skin. as they are located directly under the skin, they can be monitored and irradiated with simple methods without endangering the internal organs of the experimental animals. However, this standard method also has different disadvantages. In the case of human tumors, the so-called microenvironment of the tumor plays an important role for response to radiation therapy. Numerous studies suggest that these properties of human tumors can be better reflected by experimental orthotopic tumors, i.e. tumor growth at the site of the tissue of origin. Therefore, in orthotopic tumor models the human tumor tissue is transplanted into the corresponding organ of origin, for example into the lung or brain of the experimental animal. However, the application of this method and its effect on endpoints and questions in radiobiological experiments has so far been little investigated. Thus, an important goal of the research group is a systematic comparison of orthotopic tumor models and their subcutaneous counterparts under radiooncological aspects.

Different tumor models - left, and SAIGRT system for irradiation - right @Antje Dietrich

To irradiate the animals, the scientists can use the "SAIGRT System" (Small-Animal Image-Guided Radiotherapy) developed by the OncoRay research group "Medical Radiation Physics". This device enables image-guided, precise irradiation of orthotopic tumors, which is important in order to protect organs at risk in the vicinity of the tumor and apply high irradiation doses.

Current research topics of the group (selection):

  • Systematic comparison of orthotopic and subcutaneous tumor models under radiooncological aspects.
  • Further technical improvement of the systems used in animal experiments in cooperation with other OncoRay groups. For example, development of innovative animal couches for imaging and irradiation without changing position of the animals. This allows precise planning of the irradiation, which is carried out with the SAIGRT or also on the experimental proton beam.
  • Clarification of questions from clinical radiation therapy in the laboratory. Similar techniques are used in animal experiments which are also used in human treatment (e.g. CT, PET/MRI). Modern imaging techniques not only produce very precise results, but also make it possible to reduce the number of experimental animals and treat them as gently as possible. A multidisciplinary project is currently investigating changes in the vascular network and the oxygen supply of tumors by irradiation with photons, protons and carbon ions (in cooperation with the affiliated institution HIRO).
  • Use of patient-related models and techniques to investigate new treatment strategies and to further progress their rapid transfer into the clinic.