Stereotactic radiosurgery (SRS), also called stereotactic radiotherapy, targets radiation beams from different angles and planes on tumors and other abnormal growths in the brain.

This treatment, an alternative to invasive surgery, delivers very high doses of radiation while sparing healthy surrounding tissue. General anesthesia and incisions are not required, which reduces the risk for infection, excessive bleeding and other complications.

During the delivery of SRS, the patient is fitted with a face mask or frame attached to the scalp that keeps the head from moving, and lies on a table that slides into a machine that sends the focused beams of radiation. SRS uses such imaging modalities as CT and MRI to determine the exact location, size and shape of the tumor. Treatment is usually done in a single session and takes between 30 and 60 minutes, though in some cases (especially those involving large tumors), multiple sessions may be recommended.

The therapy is employed for patients who are unable to undergo surgery, like the elderly, and for tumors that are either hard to reach or located near vital organs.