What is Stereotactic Radiotherapy?

Stereotactic radiotherapy is a form of non-invasive treatment for some cancers and other medical conditions. It uses x-ray beams that are tightly focused on the tumor or abnormality to be treated, in contrast with traditional radiation therapy that can sometimes irradiate normal surrounding tissues. The term stereotactic refers to the precision of the placement of beams of radiation. Although one form of the procedure is sometimes termed stereotactic radiosurgery, this form of treatment is not technically considered a surgical procedure.

A medical imaging procedure such as an MRI or CT scan will usually be done beforehand to create a three-dimensional image of the abnormal area. The treatment procedure often takes between one and four hours and is done on an inpatient basis. Patients can often return home the same day and resume normal activities the following day, making this a minimally disruptive procedure. There is much less chance of bleeding or infection, compared to surgical treatment. Possible side effects include nausea or headache the day of the procedure, or swelling of the irradiated area.

Like other types of radiation therapy, stereotactic radiotherapy is not intended to remove a tumor or abnormality. Instead, the radiation causes the tumor's cells to stop reproducing, leading it to eventually shrink or disappear. Stereotactic radiotherapy is most often used as a treatment for metastatic brain cancer. In general, it is considered appropriate for tumors or abnormalities that are in close proximity to vital organs or are difficult to reach with typical surgical procedures.

This procedure can be known by a variety of names depending on the equipment used and the exact nature of the procedure based on the condition being treated. Generically, it is sometimes called stereotactic radiotherapy, or SRT for short; stereotactic radiosurgery, or SRS; or stereotactic body radiotherapy, or SBRT. The brand names for equipment or procedures used in stereotactic radiotherapy, including Gamma Knife™ and CyberKnife™, are sometimes used interchangeably with medical terminology. If the treatment is done in multiple sessions rather than all at once, it might be called fractionated stereotactic radiotherapy.

This non-invasive treatment has been used with a large variety of cancerous tumors in different parts of the body. A partial list includes the brain, the head and neck areas, the spine, the eyes, the lungs, the prostate, and the pituitary gland. The procedure is also sometimes used as a treatment for some forms of epilepsy and for certain types of abnormalities in the blood vessels.