Stereotactic Radiotherapy (SBRT) of Lung Metastasis

SBRT is an adaptation of the principles and experience gained from stereotactic brain RT. SBRT was developed in the early 90s at the Karolinska Institute in Stockholm, Sweden, and is used as an accepted alternative of treatment for patients with early stage lung cancer in many centers in Japan and a number of centers in Germany,USA and elsewhere. It is also now being used for patients who have lung metastases and extra-thoracic disease (primary or metastatic). Many reports indicate excellent local control (80-90% or higher) and minimal toxicity in well selected patients treated with thoracic SBRT. SBRT has traditionally had the following features: 1. High doses of radiation, usually in a few large fractions (it is "hypofractionated" compared with standard radiotherapy schedules) 2. Multiple radiation beams coming from different directions in the same plane ('co-planar' beams) as well as from different directions and different planes relative to the patient's body ('non-coplanar' beams) 3. Stereotactic beam placement, in that it is guided by a set of coordinates These coordinates are defined in relationship to the precise location of the tumor, determined from medical imaging (e.g. CT, MRI), rather than to a set of external marks (tattoos) or anatomical landmarks (such as bony structures)