Stereotactic radiosurgery is the very precise delivery of radiation to a brain tumor while sparing the surrounding normal brain tissue. Because it is so precise, stereotactic radiosurgery allows a higher dose of radiation to be given with more sparing of normal brain than can be achieved with conventional radiotherapy techniques.Information from MRI and/or CT scans are directly transferred to the treatment planning computer system to create a 3-D model of the tumor and surrounding normal brain. A complex radiation delivery planning system is utilized to target a high dose of radiation at the tumor while greatly limiting the dose to nearby normal brain. Special devices are used to keep the head still so that the radiation will be aimed with great accuracy at the targeted tumor.