Stereotactic radiosurgery (SRS) is a non-invasive treatment that uses dozens of tiny radiation beams to accurately target brain tumors with a single high dose of radiation. Despite its name, SRS is not a surgical procedure and does not require an incision or anesthesia. However, the radiation beams are as small and precise as a scalpel.

A computer uses three-dimensional images from MRI and CT scans to determine the exact dimensions of the tumor. It then calculates the radiation dose to be administered by nearly 200 radiation beams. This allows radiosurgeons target the tumor without affecting delicate structures nearby. SRS can treat multiple lesions in a single procedure. 

Because stereotactic radiosurgery is typically done in just one outpatient session, patients are spared from multiple radiation treatments and can return to a normal routine within a few days. 

In some cases, additional SRS treatments may be ordered by your oncologist. The single dose of radiation is split into smaller doses, or fractions. This procedure is known as fractionated stereotactic radiosurgery.

Stereotactic radiosurgery is effective for treating tumors in small areas in the head and neck that cannot be reached by surgery.  It also can be used on patients who cannot tolerate surgery or have had previous radiation therapy to the brain.

There are several types of SRS systems. MD Anderson uses Gamma Knife®, a photon-based radiosurgery system. Gamma Knife is used to treat:

  • Cancer that has metastasized (spread) to the brain, head or neck area
  • Tumors in the base of the skull
  • Malignant gliomas
  • Acoustic neuromas
  • Pituitary tumors
  • Meningiomas