Stereotactic radiosurgery and stereotactic body radiation therapy: an overview of technical considerations and clinical applications.

SRS and SBRT have emerged as effective local treatment techniques for cranial and extracranial tumors, respectively. Clinical indications for SRS and SBRTcontinue to be redefined through ongoing clinical investigations. It will be especially interesting to investigate how SRS and SBRT might best be combined with new molecularly targeted systemic agents as the field of oncology progresses through the twenty-first century.