Which types of rays do neurologists use to stop a tumor or cancer in someones brain?

High energy x-rays. Radiation oncologists and neurosurgeons frequently use high energy x-rays to control brain cancers. One of the common ones is called stereotactic radiosurgery (ie. Gamma knife, cyberknife, novalis). This is where there is a focusing of the beam (like with a magnifying glass) onto the tumor. The radiation is high energy x-rays (ie. Cobalt source from the gamma knife). The cancer is in the hot spot.