Patients with non-resectable metastases of various diseases are today treated by one of several different techniques, such as radiofrequency ablation, laser-induced thermoablation or stereotactic radiotherapy. Frequently, the employment of these therapeutic strategies is limited due to their invasiveness and treatment-associated morbidity. Furthermore, stereotactic radiotherapy is associated with a high degree of patient discomfort due to the necessary fixation of moving inner organs (lung, liver). With the development of the cyberknife radiosurgery technique, an image-guided, superselective, robot-based radiotherapy, these problems seem to be resolved. With this technique, metastases may be treated in an outpatient single-treatment setting.