Stereotactic radiosurgery is the very precise delivery of radiation to a brain tumor with sparing of the surrounding normal brain. To achieve this precision, special procedures for localization are necessary. These tools include the stereotactic frame, the CT or MRI scanner, a computerized system for calculating the radiation dose, and a precise system for delivering the radiation. Stereotactic radiosurgery offers an important alternative to more invasive treatments for many brain tumors. The role of radiosurgery vs. surgery is determined by many factors.
Conventional radiotherapy is a very useful treatment modality for many brain tumors.
The reason for fractionation is to improve the radiation effect on the tumor while minimizing the effect on the normal brain. Normal brain tolerates small, daily doses of radiation relatively well. The tumor does not tolerate the small daily doses, resulting in control of the tumor. By exploiting this difference in response, the fractionated treatment can be very effective in reducing or even eliminating the tumor while sparing the normal brain. This concept of fractionation is also very important for radiosurgery, as is discussed below.