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. Read the full article and get complete knowledge of stereotactic radiosurgery with Pritish Kumar Halder.
Body radiotherapy usually involves between one to five sessions.
Types of stereotactic radiosurgery
Doctors use two types of technology to deliver radiation during stereotactic radiosurgery.
Linear accelerator (LINAC) machines use X-rays (photons) to treat cancerous and noncancerous abnormalities in the brain and other parts of the body. LINAC machines are also known by the brand name of the manufacturer, such as CyberKnife and TrueBeam. These machines can perform SRS in a single session or over two to five sessions for larger tumors (fractionated stereotactic radiotherapy).
Proton beam (charged particle) is the newest type of stereotactic radiotherapy and is available in only a few research centers in the U.S., although the number of centers offering proton beam therapy has
greatly increased in the last few years. It can use fractionated stereotactic radiotherapy to treat body tumors over several sessions. Proton beam SBRT may be used to treat tumors in parts of the body that have previously received radiation therapy, or those that are near critical organs.
How it works
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.
Why it’s done
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
Early complications or side effects are usually temporary. They may include:
Fatigue. Tiredness and fatigue may occur for the first few days after SBRT.
Swelling. Swelling at or near the treatment site can cause signs and symptoms such as a temporary increase in pain. Your doctor may prescribe anti-inflammatory medications (corticosteroid medications) to prevent such problems or to treat symptoms if they appear.
Nausea or vomiting. Some patients may experience temporary nausea or vomiting if the radiated tumor is near the bowel or liver.
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:
- Weakened bones that may break
- Changes affecting the bowel
- Developing a new cancer (secondary cancer)
- Changes in the lungs
- Changes in the spinal cord
- Swollen arms and legs (lymphedema)
How you prepare
Preparation for SRS and SBRT may vary depending on the condition and body area being treated but usually involves the following steps:
Food and medications
- You may be asked not to eat or drink anything after midnight the night before the procedure.
- Talk to your doctor about whether you can take your regular medications the night before or morning of the procedure.
Clothing and personal items
- Wear comfortable, loosefitting clothing.
Avoid wearing the following items during SRS of the spine:
- Contact lenses
- Nail polish
- Wigs or hairpieces
- Precautions regarding medications and allergies
Tell your doctor if you:
- Have implanted medical devices in your body, such as a pacemaker, artificial heart valve, aneurysm clips, neurostimulators or stents.
- Bring any medications you are currently taking with you to the treatment center and ask about what you should do about taking your medications on the day of the procedure.
What you can expect
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.
Before the Procedure
Stereotactic radiosurgery takes a team approach, involving specialists in radiation oncology and neurosurgery. A dosimetry expert determines how the beams should be directed and a physicist calculates the amount of radiation the patient should receive, balancing risk and potential effectiveness. A key element of planning the procedure is maximizing the treatment to abnormal tissues, while protecting healthy tissues around the abnormal area.
Together, these experts spend about two weeks planning the procedure. The preparation time may be shorter in the case of an emergency.
During the Procedure
Treatment may take place at an outpatient center. You can expect to spend several hours in the outpatient center, which includes preparation for the procedure, the treatment, and observation after your procedure. You will need to have a friend or family member help take you home. The treatment takes about 30–60 minutes, and you must stay still. There is no incision or cutting.
When you arrive, you will meet the treatment team, including doctors, nurses and technicians, who will take care of you. If you are being treated for a lesion in your brain, a head-holder will be placed on your head to keep it totally still. During the treatment, you will be on a hard table, like the table used for MRI or CT scans. Your treatment team will program the machine and deliver the X-rays for your treatment, which include several doses of focused X-rays. After the treatment, you will be moved to a recovery area, where you will be observed to make sure you are feeling well. After you and your treatment team are comfortable, you can go home.
After treatment, you may resume your normal activities. Your neurology and neurosurgery team will continue to monitor you with CT and MRI during follow-up. Therapy typically only requires one treatment. Some lesions may require more than one treatment session, likely finishing within five treatments. (Conventional radiation therapy can require up to 10 sessions.)