What is stereotactic radiosurgery?
Sometimes, doctors can’t treat a disease with surgery due to the location of the problem or the health of the person who needs treatment. Brain tumors, blood vessel issues, and some nervous system conditions can be difficult to address using conventional surgery. Doctors may use stereotactic radiosurgery (SRS) to treat some of these problems.
No cutting is involved in SRS. Instead, SRS is an advanced method of radiation therapy that delivers strong and targeted doses of radiation to small areas, killing a small group of cells effectively. SRS on areas of the body other than the brain is called “stereotactic body therapy.”
SRS is a precise and powerful type of radiation therapy. SRS usually involves a single treatment of a very high dose of radiation in a focused location. Sometimes, it may involve a few treatments. During radiation therapy, your doctor uses radiation to damage the DNA of the tumor or other cells so that they no longer reproduce. This causes the tissue of the tumor to die.
SRS was originally developed to treat small, deep brain tumors. Now, it may be used for a wider array of problems in the brain and other parts of the body. Doctors use this method to treat areas that are hard to reach or close to vital organs, or they use it to treat tumors that have moved within the body. Examples of problems that your doctor can address with SRS include:
- deep brain tumors
- residual tumor cells after surgery
- pituitary tumors
- cancers of the eye
- arteriovenous malformations, which are tangled blood vessels that leak and disrupt your normal flow
- neurological problems, such as trigeminal neuralgia
- tumors in the lung, liver, abdomen, spine, prostate, head, and neck
- Parkinson’s disease
Doctors may use SRS to treat older adults or people who are too sick to have conventional surgery. Sometimes, after someone has had surgery to remove a cancerous tumor, a doctor will use SRS to kill any remaining tumor cells that the surgeon may have missed.
You’ll have one or more imaging scans, such as a CT scan or MRI prior to treatment. Your doctor may inject a contrast agent to help them understand the size and location of the tumor or other structure they need to treat. A lot of planning will go into structuring your treatment.
Tell your doctor about any medications you’re taking and any devices or implants you have, such as:
- a pacemaker
- an artificial heart valve
- implanted pumps
You should also take these precautions:
- Don’t eat after midnight the day of your treatment.
- Don’t wear jewelry, makeup, or hair products like hair spray or mousse.
- Remove any eyeglasses, contact lenses, and dentures before treatment.
A healthcare provider will start an intravenous line to give you fluids, medications, and contrast agents through your vein.
The following are the main kinds of stereotactic radiosurgery:
- Gamma knife radiosurgery involves aiming close to 200 beams of highly focused gamma radiation at a target region, such as a tumor. Doctors mostly use this for small- to medium-sized brain or head and neck abnormalities as well as functional brain disorders such as essential tremor.
- Linear accelerator machines involve the use of high energy X-rays to target large tumors by delivering radiation over several treatments. This is sometimes called CyberKnife technology.
- Doctors can use proton beam or heavy-charged-particle radiosurgery for smaller tumors throughout the body.
These methods all require a lot of imaging with CT, MRI, and other methods so that your doctor will know exactly where your tumor is and how large it is.
You’ll need to stay completely still for these methods to work. This will ensure your doctor targets the radiation to the affected tissues and that the treatment doesn’t affect as much of your normal tissue. Your doctor may place straps on you so that you’re immobile, or they may place a special facemask or a frame that attaches to your scalp to keep you from moving during the therapy.
You’ll lie down on a table that slides into a machine. The machine may spin you around to change the angle of the radiation beams. Doctors and nurses will be watching the entire time on a camera. You can speak to them through a microphone in the machine if you have any problems. Some of the professionals who may be caring for you will be:
- a radiation oncologist
- a medical radiation physicist
- a radiologist
- a dosimetrist
- a radiation therapist
- a radiation therapy nurse
Treatment usually takes between 30 minutes to one hour. One session is often all that’s necessary, but you may need additional treatments.
Stereotactic radiosurgery can cause:
- skin problems, such as red, swollen, peeling, or blistering skin
- hair loss in treatment area
- difficulty swallowing
- nausea and vomiting
- swelling, especially of the brain
In the long term, changes to the brain, spinal cord, and the lungs can occur. Radiation treatments slightly increase the risk of cancer.
Your long-term outlook depends on the condition your doctor is treating. Radiation damages the DNA of the cells in the area it targets. It may take weeks or months for those cells to stop reproducing and die off. Your doctor will continue to use CT and MRI scans to look at the size of the tumor and the area they treated.