description: The aim of this research is to define the role of an innovative methodology in the treatment of selected cerebral tumors, based on the use, in the same session, of a novel miniature radiosurgical device combined with minimally-invasive neurosurgery. This miniature x-ray generator device produces low-energy x-ray photons that are attenuated rapidly within the tissue. Radiation is released in a single session, confined to the tumor and requires only a short lapse of time. The dose distribution actually achieved has a nearly spherical shape. No specific radiation shielding is required and the dimensions and the weight of the device make it portable and easy to use in every neurosurgical operating room. This reserch aims to study two specific therapeutic applications in the treatment of cerebral tumors with this new device: on one hand interstitial radiosurgery of malignant lesions with a maximum diameter of 3.5 cm immediatly after stereotactic biopsy, and on the other hand intraoperative irradiation of surgical cavities in patients operated on for selected malignant gliomas. Furthermore this research aims to achieve an optimation of dose distribution in non spherical shape lesions, which requires the study of any single treatment ; dose conformation is achieved through the movement of the x-ray source, driven by a tele-robotic system. In this research a robotic system master-slave will be realized for the positioning of the x-ray source and for the correlation of the 3-D model of the patient, based on diagnostic images previously acquired, with the optical imaging of the patient in the operating theatre. Moreover, in order to obtain optimum resource exploitation, the sharing of this portable and easily transferable device between various italian neurosurgical-oncological centers is foreseen.