Radiotherapy at the University Hospital, Freiburg
The tradition of radiotherapy in Freiburg dates back to the year 1899. Immediately after the discovery of "X-rays" by Wilhelm Conrad Röntgen in 1895, his ideas came to Freiburg due to a personal contact with his student, the physicist Ludwig Zehnder, an external lecturer at the Physics Institute of the University of Freiburg. Röntgen himself refused a chair offered to him by the University of Freiburg in 1895 because the government of Baden was not able to fulfil his requirements for the equipment of the laboratory. So it was Ludwig Zehnder who produced X-ray tubes in Freiburg and was first to make investigations on X-rays in the summer of 1896.
It was in 1910, when the Freiburg gynaecologist Bernhard Krönig was looking for possibilities to use the Röntgenstrahlen and the radiation from radium in medicine. With the physicist Walter Friedrich, a student of W. C. Röntgen, he started a collaboration to investigate the effects of ionizing radiation on human tissue. Thus Walter Friedrich became Freiburg's first medical physicist.
Krönig and Friedrich knew about the necessity of basic research in this field of radiotherapy and that was the reason for the foundation of the "Radiologisches Institut" in Freiburg in 1914. In this institute Walter Friedrich investigated the fundamental principles of dosimetry.
The problem of the measurement of ionizing radiation was also studied at the Physics Institute of the University of Freiburg by Otto Glasser and by Wilhelm Hammer, the later founder of PTW. Both developed dosemeters with an ionization chamber. In 1922 Hammer dosemeters became commercially available, after Hammer had solved the problems of the transportation of very small ionization currents from the ionization chamber to the meter on the one hand, and the exact acquisition of very low electrical charges by using a highly sensitive electro-static relais on the other hand.
Clinic for Radiotherapy
Nowadays, the Clinic for Radiotherapy is placed in a separate part of the clinic and has on the lowest floor five rooms with linear accelerator for patient treatments with external photon and electron radiation. All linacs are equipped with MLCs and electronic portal imaging systems. Three of the accelerators are prepared to treat patients with intensity modulated irradiation (IMRT). Two of them are having additionally integrated on board imaging systems for kV-imaging and Cone Beam CT, used for IGRT.
Brachytherapy is performed using an HDR afterloader; the implantation of sources and catheters is ultrasound controlled and documented by an integrated brachytherapy kV-imaging system. For the preparation of the treatment there is a CT scanner and a simulator. 3D planning for external radiotherapy and brachytherapy is performed by several treatment planning systems. Further, for intraoperative radiotherapy (IORT) we use a dedicated linac and a HDR-afterloader in a separate operating theatre. Up to 40 inpatients can be attended at the "Marie Curie" radiotherapy station.
The staff in our clinic consists of radiation oncologists, medical physicists, radiation technologists, dosimetrists, it-service, attendants and an engineering group. Basic research on radiobiology is performed in a separate laboratory.
The major focus of the clinic is the 4D high conformal radiotherapy, based on target volume definition from CT and molecular imaging devices (PET, PET-CT, MR), followed by calculation of dose-distributions, using adequate algorithms. Precise 3D calculations however are based on a precise dosimetry and tools for routine QA. The QA during the radiotherapy is performed by IGRT and in vivo dosimetry for special treatments.
For this purpose we use equipment coming from PTW-Freiburg together with inhouse developed and produced tools. Following our main focus, together with PTW-Freiburg new products of the company are tested in our clinic for the routine application in a sense of high precision radiotherapy.