A specialized type of external beam radiation therapy called stereotactic radiation uses focused radiation beams targeting a well-defined tumor. It relies on detailed imaging, computerized three-dimensional treatment planning and precise treatment set-up to deliver the radiation dose with extreme accuracy. There are two types of stereotactic radiation:
SRS/SBRT/SABR is generally best for very small tumors. Doctors use specialized scans to pinpoint exactly where the tumor target is located. A customized holder may be used to keep the body perfectly still during treatment. Some treatment machines have the ability to adjust for patient motion such as during breathing.
These techniques allow doctors to give a high dose of radiation to the tumor in a short amount of time. SRS/SBRT/SABR is a type of external beam radiation therapy that can be completed in one to five treatments.
The advantage of SRS/SBRT/SABR is it delivers the right amount of radiation to the cancer in a shorter amount of time than traditional treatments. Plus the treatment is delivered with extreme accuracy, minimizing the effect on other nearby organs.
A disadvantage of SRS/SBRT/SABR is that this technique is suitable only for small, well-defined tumors that can be seen on imaging such as CT or MR scans, thus this approach is not suitable for all situations. Also, the amount of radiation that may be safely delivered may be limited if the cancer is located close to a sensitive normal structure, such as the spinal cord or bowel.
There is sometimes confusion about the branding of equipment separate from the terminology of SRS or SBRT/SABR. Stereotactic radiation may be delivered by a number of different devices; brand name stereotactic treatment machines you may hear mentioned include Axesse, CyberKnife, Gamma Knife, Edge, Novalis, Primatom, Synergy, X-Knife, TomoTherapy, Trilogy, Truebeam, Versa HD or View Ray. It is important not to confuse these brand names with the actual type of stereotactic radiation under consideration.
Stereotactic radiosurgery (SRS) is used to treat conditions involving the brain or spine including:
Stereotactic body radiation therapy (SBRT) is used to treat small tumors in the chest, abdomen or pelvis that cannot be removed surgically or treated with conventional radiation therapy, including:
These lists cover commonly treated conditions but cannot include every possibility. Stereotactic radiation may be useful for other cancers not readily addressed with surgery or conventional radiation therapy. Patients with tumors that are small and few in number are the best candidates for stereotactic techniques. Not all patients can benefit from this type of treatment.
Your radiation oncologist can tell you whether this approach is an option for your specific condition as new research continues to broaden the use of this technology.
Radiation oncologists are highly trained, board certified and licensed physicians who use radiation therapy in its various forms to care for patients with cancer and other conditions, and who oversee the care of each person undergoing stereotactic radiation. Radiation oncologists team up with neurosurgeons for stereotactic radiosurgery of the brain or spine.