Stereotactic radiation therapy is a specialized form of external radiation treatment where very high doses of precise radiation are directed at small targets. Because of the high level of radiation, the number of individual treatments required is less than in typical external beam radiotherapy (usually between 1 and 5 sessions). However, these treatments may take 30 to 60 minutes to deliver.
The areas that are typically treated with these techniques include small tumors in the brain, lung, liver or spine. These treatments are often called Stereotactic Body Radiotherapy (SBRT). The term Stereotactic Radiosurgery (SRS) typically refers to a single high-dose external radiation treatment typically directed at a small brain tumor.