The Leksell Gamma Knife Perfexion intracranial radiosurgical tool features a unique collimator design that enables complicated tumors to be treated with absolute precision in a single run with one push button for 99% of all cases. A single robotic system with three collimators allows the collimator size to automatically change, according to the treatment plan, making it especially suitable for treatment of multiple targets, which in most cases means brain metastases.