The Basics of Gamma Knife Radiosurgery
An example of a radiation treatment is gamma knife radiosurgery. Another name for it is stereotactic radiosurgery. Even though a Gamma Knife operation is called surgery, incisions are not made during it. It isn't a knife either. The Gamma Knife uses extremely focused gamma ray beams to treat a lesion or growth (tumor). It is mostly utilized in the brain. Without the necessity for an incision, the gamma radiation beams deliver a very powerful dosage of radiation to a tiny area. Cells are destroyed by radiosurgery so they can't proliferate. Over time, a lesion or tumor will get smaller. Because the outcome is akin to eliminating a lesion through surgery, gamma knife radiosurgery is referred to as surgery. With little impact on neighboring healthy tissue, the radiation beams are precisely directed to approach the lesion. One form of radiosurgery system is the Gamma Knife system. A brand name is Gamma Knife.
The Gamma Knife technique is carried out by a medical staff. A radiation oncologist is in charge of the group. This person is an expert in cancer radiation therapy. The other team members could be:
- Radiation therapist
- Registered nurse (RN)
- Medical physicist
- Other healthcare providers as needed
Gamma Knife treatment in most cases involves these steps:
- Head frame placement. A box-shaped frame is fastened to the head to prevent movement over the course of the treatment. The head frame is attached to the skull using special pins made for this purpose. The head frame serves as a guide to direct the gamma ray beams precisely to the lesion's site.
- Tumor or lesion location imaging. Once the head frame is in position, a CT scan or MRI will be used to pinpoint the exact location of the lesion. A CT scan produces a detailed image using a sequence of X-rays and a computer. A computer and huge magnets are used in MRI to create images. If a blood vessel lesion, such as arteriovenous malformation (AVM), is being treated, you could require a cerebral angiography. An X-ray and a specific dye are used in a cerebral angiography. To detect issues with the blood vessels, the dye is injected into a large blood vessel.
- Radiation dose planning. The radiation therapy team will decide on the treatment strategy following the CT scan or MRI. A medical physicist will decide the appropriate course of action based on the imaging scan results and other data.
- Radiation treatment. A sort of helmet with several holes is placed over the head frame once the patient is in the proper posture for the treatment. The radiation beams can better hit the target thanks to these perforations. The duration of the procedure can range from a few seconds to several hours. The type and location of the area being treated will determine how long it will take. For a lesion, often just one therapy session is required.
Why might I need Gamma Knife radiosurgery?
Gamma Knife radiosurgery is most often used to treat:
- Small and medium tumors and lesions in the brain
- Trigeminal neuralgia, when pressure on the trigeminal nerve causes spasms of extreme facial pain
- Acoustic neuroma, a noncancerous tumor in the brain that affects nerves that control hearing
- Blood vessel lesions, such as AVM
There may be further justifications for your doctor's recommendation of Gamma Knife radiosurgery. If traditional surgery is unable to access a brain lesion, gamma knife radiosurgery may be utilized. Or it might be employed when a patient is unable to undergo common surgery, like a craniotomy. A Gamma Knife treatment has effects that develop gradually over time. This makes it inappropriate for those who require immediate results. Discuss the rationale behind your procedure with your provider.
What are the risks of Gamma Knife radiosurgery?
All procedures have some risks. The risks of this procedure may include:
- Swelling of the brain
- Nausea and vomiting
- Hair loss near treated area (temporary)
- Soreness and swelling in the area being treated
- Loss of balance
- Vision problems
- Radiation exposure
- Pain at the head frame pin insertion sites
Inform your healthcare practitioner if you are pregnant or believe you may be. Birth abnormalities could result from pregnant radiation exposure.
Depending on your general health and other conditions, your risks may change. Find out from your physician which hazards most concern you. Any worries you may have can be discussed with them.
How do I get ready for Gamma Knife radiosurgery?
The technique will be explained to you by your healthcare provider. Pose any queries you may have. A consent form authorizing the procedure may be given to you for signature. Examine the form thoroughly. If anything seems unclear, ask a question.
Tell your provider if you:
- Are pregnant or think you may be pregnant
- Are allergic to contrast dye or iodine
- Are sensitive to or allergic to any medicines, latex, tape, or anesthetic medicines (local and general)
- Take any prescription or over-the-counter medicines, vitamins, or herbal supplements
- Have had a bleeding disorder
- Take blood-thinning medicine (anticoagulant), aspirin, or other medicines that affect blood clotting
- Have any type of implant, such as a pacemaker, implantable defibrillator, artificial heart valve, surgical clips for a brain aneurysm, implanted medicines pump, chemotherapy port, nerve stimulators, eye or ear implants, stents, coils, or filters
Make sure to:
- Stop taking certain medicines before the procedure, if instructed by your provider
- Not eat or drink for 8 hours before the procedure or as instructed by your provider
- Wash your hair with special shampoo either the night before or morning of the procedure, as instructed
- Plan to have someone drive you home after the procedure
- Follow any other instructions your provider gives you
You may have blood tests, urine tests, and other tests or exams before the procedure. Your provider will tell you more.
What happens during Gamma Knife radiosurgery?
You may have your procedure as an outpatient. This means you go home the same day. Or it may be done as part of a longer stay in the hospital. The way the procedure is done may vary. It depends on your condition and your healthcare provider's methods. In most cases, the procedure will follow this process:
- You may be asked to remove your clothes. If so, you'll be given a hospital gown to wear. You may be asked to remove jewelry or other objects.
- An IV (intravenous) line may be put into your arm or hand.
- Hair in the area around the head frame insertion sites may be trimmed. The skin on your head will be cleaned where the pins for the head frame will be placed.
- A numbing medicine (local anesthetic) will be injected at the head frame pin insertion sites. The head frame will be attached to your head with pins that are inserted into your skull. You may feel some pressure during the placement of the head frame. This feeling should go away in a few minutes.
- After the head frame is attached, you'll undergo brain imaging. This is done so that the location of the brain tumor or lesion can be precisely found for the treatment. The brain imaging may be done with a CT scan or MRI. After the brain imaging, the team will use the images to create your treatment plan. In some cases, the imaging may be done before the day of your radiosurgery.
- You'll be taken into the room where the Gamma Knife equipment is located. You'll lie down on a sliding table. A special helmet called a collimator helmet may be fitted over the head frame. The collimator helmet has 201 holes in it. These holes allow radiation beams to pass through it into your brain in a precise pattern that is determined by a computer.
- Once the helmet is in place, the table will slide into the Gamma Knife unit. You may hear a clicking sound as the helmet moves into place in the machine.
- The treatment team will go into another room. You can talk with the team through an intercom. They can hear you at all times. You'll be watched on a video monitor.
- You will not feel or hear anything from the Gamma Knife unit during the treatment session.
- The treatment session may last 2 to 4 hours. The length of the session will depend on the treatment plan created for you.
- After the session is over, the table will slide out of the Gamma Knife machine. You'll be able to get up, unless you had an angiogram before the Gamma Knife procedure.
- The head frame will be removed. The pin insertion sites will be cleaned. Sterile dressings will be put on the sites.
What happens after Gamma Knife radiosurgery?
After the procedure, you'll be watched for a period of time.
Once you're able to drink, the IV line will be removed. You may eat and drink as you're able. You may feel some discomfort after the procedure, such as a headache or nausea. Tell your healthcare provider so you can be treated for these effects.
You'll most likely go home at the end of the day. You'll need to have someone drive you home. If needed, you may stay in the hospital overnight. Once you’re home, you may go back to your normal diet, medicines, and activities, unless your provider tells you something different. You may be told to avoid strenuous activity for a period of time.
You'll most likely be allowed to gently shampoo your hair the day after the procedure. But, don't scrub the pin sites on your head until they've completed healed. Healing usually takes about a week.
Call your provider if you have any of the below:
- Severe headache that’s not relieved by pain medicine
- Any weakness, numbness, or vision problems that are new or worse
- Bleeding or other fluid leaking from the pin sites that doesn’t stop
Your provider may give you other instructions after the procedure.
Before you agree to the test or the procedure make sure you know:
- The name of the test or procedure
- The reason you are having the test or procedure
- What results to expect and what they mean
- The risks and benefits of the test or procedure
- What the possible side effects or complications are
- When and where you are to have the test or procedure
- Who will do the test or procedure and what that person’s qualifications are
- What would happen if you did not have the test or procedure
- Any alternative tests or procedures to think about
- When and how you will get the results
- Who to call after the test or procedure if you have questions or problems
- How much you will have to pay for the test or procedure