Emergence of stereotactic body radiation therapy

Stereotactic body radiation therapy (SBRT) evolved from the application of stereotactic radiosurgery, which is focused intracranial radiation. SBRT offers high doses of specific radiation with oligofractions (five or less) to a specified target, providing local control to circumscribed tumors while sparing surrounding normal tissue. Commonly treated cancers include tumors of the lung and liver. The challenge with SBRT is to account for organ motion and the achievement of precise targeting. SBRT uses three-dimensional radiation therapy planning, intensity-modulated radiation therapy, as well as image-guided organ motion and gating. SBRT is based on the premise of geometric avoidance, targeting the tumor with the goal of complete avoidance of the surrounding normal tissues and critical organs. An SBRT course of treatment ranges from one to five treatments (hypofractionated) and, therefore, differs from conventional radiation, which is usually a prolonged course ranging from two to six weeks of daily treatment.