Prof. Dr. rer. nat. Wolfgang Schlegel

The IRIS-collimator was developed in collaboration with Accuray Inc. for the dynamic beam collimation of the “Cyber¬knife” accelerator system. It has been shown, that with the use of this collimator the beam delivery times can be reduced by a factor of 2-3, while maintaining or even improving the quality of the dose distributions (Echner et al., 2009).

Because failure of local tumor control is still a problem in many cancer patients, there is an urgent need to optimize existing and to develop new and more effective radiotherapy techniques for localized tumors. Research of the de- partment is focusing on new conformal radiotherapy techniques with photons, electrons, protons and heavy ions. In the frame of ongoing projects in photon and ion therapy, the Department’s future work concentrates on the consi- deration of dynamic changes of target volumes and organs at risk under therapy, due to therapeutic response, organ movement or patient repositioning. Image guided and time-adapted therapy is being developed to combine conformal dose delivery with online imaging of 3D anatomy and online monitoring of 3D dose distributions. The department is furthermore integrating molecular imaging into treatment planning and dose delivery with the goals of boosting radio- resistant tumor subvolumes and avoiding radiosensitive normal tissue structures. Establishing mathematical and biolo- gical models of tumor and normal tissue response is a further tool to optimize treatment schemes and techniques.One of the strengths of the department is the direct transfer of prototypes of software and hardware development into clinical applications in close collaboration with the Clinical Cooperation Unit Radiotherapy. Thus the department is also active in testing and evaluating new techniques as well as in establishing adequate quality assurance programs.

The future research and development projects comprise the fields of IGRT, biological adaptive radiotherapy, Ion therapy and the physical parts of different radiation biology projects.
Research related to IGRT with photons will be followed by a phase where the results are transferred to the clinical application at DKFZ. We want to accompany the development of real-time 3D-imaging of the patient in treatment position. Promising new approaches refer to combinations of MR-imaging or 3D x-ray imaging with a new generation of treatment machines.
To support the general aim of a biologically guided radiotherapy at DKFZ we will pursue the development of a unified treatment planning and optimization platform that specifically accounts for the information provided by biological input data.
In heavy ion therapy, new dosimetric methods will be developed. A project for Monte Carlo simulation of the effects of secondary electrons in the dosimetry of heavy ions and the investigation of perturbation factors for ionization chamber Dosimetry has been started. For ion beam treatment planning, the possibility to use radiographic imaging with ion beams will be investigated.
In the field of radiobiological modeling, the existing model shall be extended by incorporating a patient model and information obtained in biological imaging. With these developments, it will be possible to apply the model also to clinical tumors.