Over the last 20 years image-guided tumor therapy experienced a dramatic development. This development is ruled by two facts: (1) continuously improved imaging with respect to tumor detection, therapy monitoring and guidance, as well as post therapy follow-up; and (2) significant advances in the usability and efficacy of minimal-invasive therapeutical techniques and devices. Robust, high resolution and high contrast imaging by ultrasound, computed tomography and magnetic resonance tomography together with the use of contrast agents for the respective imaging modalities is the crucial component of detecting, characterizing, staging, and follow-up in most tumors. Moreover, rapid real-time imaging by ultrasound, projection radiography, CT, and even MRI allow online guidance for the placement of minimal-invasive therapy devices as well as monitoring instant local therapeutic effects. With respect to general oncological and surgical conditions, surgery is the method of choice in the therapy of most tumors. However, overall only 15–30% of patients with malignancies are suitable for a primary surgical therapy with curative intention. Therefore, modern chemotherapies including the wide use of biologicals are considered to be the main columns in adjuvant and neoadjuvant treatment regimens—taking into account that there will be no long-term curative effect in most of the cases. Based on the positive data of surgical resection in patients with limited tumor load and the resulting longterm survival, the concept of local ablative therapy—with and without concomitant chemotherapy—evolved for cases where a surgical treatment is not possible anymore due to medical and/or technical reasons. In general, four basically different ablative local