Stereotactic radiosurgery: Stereotactic radiosurgery (SRS) can be used to deliver one or more than one high dose radiation to small tumors. Highly accurate image-guided tumor targeting and patient positioning is used in SRS. High dose can be given without causing harm to normal tissue.
SRS can be used on tumors with properly defined edges. It is most commonly used in spine and brain tumor treatment and brain metastases from other cancers. Radiation therapy is given to the entire brain, in addition to SRS, in the treatment of some metastases, also known as whole-brain radiation therapy. A head frame or some other device is used to immobilize the patient while treating, to ensure accuracy in delivering dosage in SRS.
Sterotactic body radiation therapy
Radiation is given in fewer sessions in this therapy. Stereotactic body radiation therapy (SBRT) involves using smaller radiation fields and higher doses than 3D-CRT. SBRT is used for treatment of tumors outside the spinal cord and brain. These tumors tend to move with body movement and so it is difficult to target them accurately. SBRT is delivered in more than one dose and can be used in the treatment of isolated and small tumors, including cancerous liver and lungs.
Doctors call SBRT systems by their brand names such as CyberKnife.