Stereotactic Radiotherapy of the Resection Cavity of Brain Metastases vs. Post-operative Whole-brain Radiotherapy

"For radiosurgery, patients will be immobilized. Treatment planning including the MRI and planning CT should be performed 1 -2 weeks before SRT and treatment finished at latest 3-4 weeks after surgery. Planning should be as close to SRT as possible.~Organs at risk such as the brain stem, optic nerves, chiasm and spinal cord will be contoured. The Clinical Target Volume 1 (CTV1) will be defined as the resection cavity based on MRI and CT including T1 contrast enhanced changes around the resection cavity. The Clinical Target Volume 2 (CTV2) will be defined as a 3mm margin added to CTV1 by isotropic expansion and slightly adjusted as deemed appropriated by the experienced contouring physician. The Planning Target Volume (PTV) will be an additional margin of 1mm added to CTV2 by isotropic expansion.~Treatment planning will be performed using Accuray's Multiplan or subsequent approved treatment planning systems for Cyberknife."

"For WBRT, an individual head fixation mask is manufactured for each patient, and treatment planning is performed as virtual simulation or 3D-conformal RT planning based on CT-imaging. The portals include the whole brain with special focus as including the skull base areas and lamina cribrosa. For low infratentorial lesions, the treatment volume may include the whole brain down to the second cervical vertbra.~RT will be applied with two portals (e.g. 87°and 273°) using a 6 MeV linear accelerator.~For WBRT, a total dose of 30 Gy in 3 Gy fractions will be applied."