Radiosurgery, also called stereotactic radiosurgery, is a precise form of radiation therapy that uses intense doses of radiation to treat a condition in the head or neck without a surgical incision.
Radiosurgery is called "surgery" because a result similar to an actual surgical procedure is achieved by radiation therapy. The beams of radiation are precisely focused to reach the tumor, lesion, or other area being treated, with minimal effect on surrounding healthy tissue.
Like other forms of radiation therapy, radiosurgery works by distorting or destroying the DNA of tumor cells, rendering them unable to reproduce and grow. As a result, the tumor shrinks in size over time. For blood vessel disorders, such as an arteriovenous malformation, the targeted blood vessels eventually close off after treatment. For other areas or structures in the brain that are the targets−as in treating obsessive-compulsive disorder−activity of dysfunctional regions is diminished in order to provide relief.
Radiosurgery can be performed during a single session or over multiple sessions-in which case it is called "fractionated radiosurgery." There are three types of radiosurgery systems:
Gamma Knife system
The Gamma Knife system is a stationary system that uses beams of highly focused gamma rays to treat lesions in the brain. Many beams of gamma radiation join to focus on the lesion under treatment. Gamma Knife radiosurgery is most often used to treat tumors and other lesions in the brain.
Linear accelerator systems
Linear accelerator (LINAC) systems use high-energy X-rays to treat a tumor or other lesion. The LINAC system is not specifically made for treating lesions in the brain; it can be used to treat any area in the body. Some common types of LINAC systems include CyberKnife®, X-Knife®, Novalis®, and Peacock®. In addition to using X-rays rather than gamma rays, LINAC systems also differ from Gamma Knife in that the machinery moves around the patient during treatment.
Proton beam therapy
Proton beam therapy is the most widely used type of particle beam therapy. Rather than using rays of radiation, such as gamma rays or X-rays, particle beam therapy uses particles called protons. A machine called a cyclotron emits the particles. Proton beam therapy can be used for radiosurgery procedures or for fractionated radiotherapy. Only a limited number of locations in the United States have the machinery for proton beam therapy.
The preferred radiosurgery system at Columbia University Irving Medical Center/NewYork-Presbyterian Hospital is Gamma Knife because it is superior to other systems when treating brain lesions. Our multidisciplinary team at the Gamma Knife Center has successfully treated thousands of patients with Gamma Knife find is equipped with the latest Gamma Knife system, the Leksell Gamma Knife Icon. Using the Leksell Gamma Knife Icon, our neurosurgeons can treat both small and large tumors and lesions near critical structures, neither of which was possible with earlier models.
When is Stereotactic Radiosurgery performed?
Radiosurgery can be used to treat many conditions in the brain, including:
- Blood vessel disorders, such as arteriovenous malformation
- Trigeminal neuralgia
- Movement disorders, such as essential tremor
- Obsessive-compulsive disorder
- Primary brain tumors, in particular:
- Pituitary tumor
- Acoustic neuroma
- Glomus jugulare tumor
- Pediatric brain tumors
- Metastatic brain tumors
This is not a complete list of conditions treated with radiosurgery. Your physician may recommend radiosurgery for a condition not listed here.
The advantage of radiosurgery, and the reason it is recommended over traditional surgery in certain situations, is its ability to reach hard-to-access brain lesions. In addition, radiosurgery can be used for individuals who cannot tolerate an open surgery treatment, such as craniotomy.
However, radiosurgery is not recommended for patients whose condition requires immediate treatment because the therapeutic effects of radiosurgery occur gradually over months or even years, depending on the treated condition.
Radiosurgery can be used for both children and adults.
How should I prepare for Stereotactic Radiosurgery?
The treatment team for radiosurgery typically includes a neurosurgeon, a radiation oncologist, a radiation therapist, and a registered nurse. Also part of the team is a medical dosimetrist and a medical physicist, who work together to calculate the exact number of exposures and beam placement necessary to obtain the radiation dose that the radiation oncologist prescribes. In addition, other healthcare professionals not listed here may be part of your treatment team.
Radiosurgery is performed in similar ways across all three systems-Gamma Knife, linear accelerator, and proton beam therapy. There may be slight variations depending on your condition. The procedure is usually performed on an outpatient basis but may require an overnight stay if complications arise.
Beforehand, you will be instructed to remove any clothing, hairpins, jewelry, dentures, or other objects that could disrupt the procedure; you will also be provided with a gown to wear. An intravenous (IV) line is often started in the arm or hand to administer medications and/or fluids during the procedure.
The head is then prepared for placement of a customized face mask or box-shaped head frame. If a face mask is used, the technique is referred to as frameless radiosurgery; if a head frame is used, the technique is called frame-based radiosurgery. The choice of method depends on the condition treated, but the purpose remains the same: to secure the head so there is no movement during the procedure. Shaving any portion of the head is not required for either technique.
To prepare the head for a head frame, the hair is separated and flattened; an antibiotic gel is then applied to the hair to make it thick and greasy. Next, the head frame can be properly secured to the head.
To prepare for a face mask, you will be asked to lie down on the table, and then a thermoplastic mesh will be draped across your face. Since it has an opening for the nose and perforations, the face mask allows for comfortable breathing. The mask is then formed to fit every groove and ridge in your face exactly. The mask will fit tightly but also be comfortable to wear throughout the procedure. The mesh typically takes about 30 minutes to harden into a custom-fit face mask.
To help you relax throughout the procedure, you may be given a mild sedative. You will remain awake and conscious throughout the procedure but will not feel pain.
After the head frame or face mask is attached, your brain will be imaged so that the brain lesion can be precisely located. Imaging studies used may be a computed tomography (CT) scan, a magnetic resonance imaging (MRI) scan, or a cerebral angiogram.
After the imaging study has been completed, the treatment team will finish your treatment plan and you will have some time to rest and relax. The treatment team will use the results of the imaging scan, as well as other information, to determine the best treatment for you.
Once the treatment plan is complete, you will be taken into the room where the radiosurgery equipment is located. You will be asked to lie down on a sliding table connected to the radiosurgery system. The table will then slowly slide you, head first, into the large opening of the system.
In an attached room, the treatment team will observe and monitor you from start to finish on a video monitor. Throughout the procedure, you will have an intercom available to communicate with the treatment team, and they will be able to hear you at all times.
The radiosurgery system will mostly be silent throughout the procedure.
The number of oil treatment sessions will depend on your specific situation and the radiosurgery system used. Your time spent on the table inside the radiosurgery unit may last between 15 minutes and a few hours; the duration will depend on your unique treatment plan.
Once the treatment session is complete, the treatment table will slide out of the radiosurgery system. At this time, you will be allowed to get off the table, unless you had a cerebral angiogram before the procedure. If you had a cerebral angiogram, you will need to remain lying still with the affected leg straight for a few hours until the site in the groin where the catheter was inserted is no longer likely to bleed.
Last, the head frame or face mask is removed.
The IV line will be removed once you can take liquids by mouth. You may take liquids and solid foods as tolerated.
How is Stereotactic Radiosurgery performed?
Your physician will explain the radiosurgery procedure to you, and during this time, you can ask any questions you may have. Once you understand the procedure, you will be asked to sign a consent form that gives your physician permission to do the procedure. It is important that you read the form carefully and ask questions if something is unclear.
Make sure you inform your physician of any allergies or sensitivities to medications, tape, latex, iodine, or contrast dyes. You must tell your physician about all supplements, including herbs or vitamins, and all medications, both over-the-counter and prescription, that you are taking.
If you have a history of bleeding disorders or if you are taking any anticoagulant medications, aspirin, or other medications that affect blood clotting, inform your physician. Your physician may ask that you temporarily stop these medications before radiosurgery.
Be sure to tell your physician if you have any implant(s), including, but not limited to, a pacemaker and/or implantable defibrillator, surgical clips for a brain aneurysm, artificial heart valve, chemotherapy port, implanted medications pump, nerve stimulators, ear or eye implants, coils, stents, or filters.
If you know you are pregnant or if it is possible that you may be pregnant, it is essential that your physician know. Women of childbearing age may be asked to submit a urine specimen for pregnancy testing before the procedure because radiation exposure during pregnancy can cause birth defects.
You may be provided with a special shampoo to wash your hair with the night before or the morning before the procedure.
The morning of the procedure, you may eat a light breakfast at home and should wear loose, comfortable clothing when you arrive at the hospital. Do not wear makeup, jewelry, body piercings, or contact lenses; instead, wear your glasses.
Most patients can go home the same day of the procedure, but if your situation requires an overnight stay, pack a light bag. A few items that patients commonly like to bring include dentures, toiletries, and fresh clothing for when they are discharged from the hospital.
Make arrangements for transportation back home because you will not be allowed to drive yourself home after the procedure.
Depending on your medical condition being treated, your physician may request other specific preparation.
What can I expect after Stereotactic Radiosurgery?
How long will I stay in the hospital?
Radiosurgery is generally performed on an outpatient basis, so you most likely will be allowed to go home within a few hours after the procedure. If complications—which are rare—arise, you will be admitted to the hospital for monitoring overnight.
Will I need to take any special medications?
Some patients may have headaches or nausea after the procedure. Medications will be prescribed to provide relief.
When can I resume exercise?
You can most likely return to your exercise routine and other forms of strenuous activity about 18 to 24 hours after the procedure is complete. Always check with your physician first, though, before resuming exercise.
What follow-up will I receive?
After the procedure, you will have follow-up appointments scheduled with your neurosurgeon and, depending on your treated condition, possibly with other team members too. How many appointments you need to attend depends on your unique situation. Imaging studies are usually ordered during follow-up visits to monitor the treated lesion and assess the effect radiation therapy had on it. The effects of radiosurgery may not be seen for weeks, months, or years, depending on the condition treated.
Call your physician for immediate follow-up if you experience any of the following:
- Any weakness, numbness, or vision problems that are new or worsening
- Severe headache that is not relieved by medication
Will I have any long-term limitations due to radiosurgery?
Typically, patients do not have long-term limitations due to the radiosurgery procedure. Possible long-term limitations generally depend on the lesion treated.