Radiosurgery is a radiation delivery procedure that precisely deliver large radiation doses to tumors and other relevant anatomical targets in a single session or in a small fraction of sessions (typically up to five). The goal of this non-invasive procedure is to destroy, or make inactive, the target anatomy without harming nearby healthy tissue and without involving traditional surgery.

Historically, radiosurgery began by treating targets in the brain and has now extended to targets in the spine and other extracranial organs. Recent studies have suggested this strategy can be more effective at killing or controlling certain types of cancer.

The clinical targets for radiosurgery are relatively small and well defined. High-resolution 3D imaging techniques such as CT and MRI help identify and clinically define these targets and the critical structures surrounding them. Sometimes a small number of targets are treated simultaneously. As they involve a small number of fractions of radiation—hypofractionation—radiosurgical procedures are generally completed within the same week.

Radiosurgery with the Novalis Tx™ radiosurgery platform is typically performed in 30 minutes or less. Recent advances in treatment delivery with Varian RapidArc has the promise to allow a single 6 Gy fraction to be performed in six minutes. These treatment times compare with other systems where treatment may take hours for a single fraction. Shorter treatment times increase patient comfort and minimize patient motion. This makes compensating for movement easier, and can result in more precise treatments being performed.