Stereotactic radiosurgery (SRS) is a type of radiotherapy. When it's performed on the body rather than the brain, this procedure is sometimes called stereotactic body radiotherapy (SBRT) or stereotactic ablative radiotherapy (SABR).
The procedure uses many precisely focused radiation beams to treat tumors and other problems all over the body. SBRT is used to treat tumors in the lungs, spine, liver, neck, lymph node or other soft tissues.
Because there's no incision, SBRT isn't a traditional type of surgery. Instead, SBRT uses 3D imaging to target high doses of radiation to the affected area. This means there's very little damage to the surrounding healthy tissue. Like other forms of radiation, stereotactic radiosurgery works by damaging the DNA of the targeted cells. Then, the affected cells can't reproduce, which causes tumors to shrink.
Body radiotherapy usually involves between one to five sessions.
Doctors use two types of technology to deliver radiation during stereotactic radiosurgery.
All types of stereotactic radiosurgery and radiotherapy work in a similar manner.
The specialized equipment focuses beams of radiation on a tumor or other target. Each beam has very little effect on the tissue it passes through, but a targeted dose of radiation is delivered to the site where all the beams intersect.
The high dose of radiation delivered to the affected area causes tumors to shrink and blood vessels to close off over time following treatment, robbing the tumor of its blood supply.
The precision of stereotactic radiosurgery means there's minimal damage to the healthy surrounding tissues. In most cases, radiotherapy has a lower risk of side effects compared with other types of traditional surgery or radiation therapy.
Around 50 years ago, stereotactic radiosurgery was pioneered as a less invasive and safer alternative to standard brain surgery (neurosurgery), which requires incisions in the skin, skull, membranes surrounding the brain and brain tissue.
Since then, the use of SRS has expanded widely to treat a variety of neurological and other conditions. SBRT may be used to treat cancers of the liver, lung, abdomen, lymph nodes and spine.
Stereotactic radiosurgery doesn't involve surgical incisions, so it's generally less risky than traditional surgery. In traditional surgery, you may have risks of complications with anesthesia, bleeding and infection.
Early complications or side effects are usually temporary. They may include:
Rarely, people may experience late side effects, months after treatment, although this varies for each body site. Your physician will discuss potential risks more thoroughly with you. These may include:
Preparation for SRS and SBRT may vary depending on the condition and body area being treated but usually involves the following steps:
Wear comfortable, loosefitting clothing.
Avoid wearing the following items during SRS of the spine:
Tell your doctor if you:
Stereotactic body radiotherapy is most commonly delivered as an outpatient and takes between 20 to 60 minutes for each treatment. While not common, your doctor will advise you if a family member or friend will need to accompany you for the treatment.
Preparation for stereotactic radiosurgery of the body involves several steps, including:
Simulation. A radiation oncologist will conduct a simulation. This step determines the best placement of your body to align it with the radiation beams. Your body will be held very tightly and still by an immobilization device. Tell your doctor if you have claustrophobia.
After you are immobilized, imaging scans will be taken. Your doctor might perform a 4DCT to capture information about how your tumor moves when you are breathing. A 4DCT is most often used on tumors located in the liver or lungs. After the scans, you'll probably be sent home before the next stage. Sometimes, holding your breath for 10-30 seconds at a time during treatment may be required to reduce movement of the tumor.
Children are often anesthetized for the imaging tests and during the radiosurgery. Adults are usually awake, but in rare instances, you might be given a mild sedative to help you relax if you're feeling very anxious.
The LINAC machine moves and rotates around the target during treatment to deliver radiation beams from different angles. The treatment takes less than 30 minutes to an hour.
Having SBRT is kind of like having an X-ray. During the procedure:
After the procedure, you can expect the following:
The treatment effect of stereotactic radiosurgery occurs gradually, depending on the condition being treated:
You'll receive instructions on appropriate follow-up exams to monitor your progress.