Gamma Knife radiosurgery is a form of radiation therapy that accurately focuses hundreds of individual laser beams at a tumour. It is often used as an alternative therapy to chemotherapy, surgery or other forms of radiation oncology to treat brain tumours.
Why do you need Gamma Knife radiosurgery?
Gamma Knife radiosurgery can be used to treat the following conditions:
Benign brain tumours
Malignant brain tumours
Nerve disorders, such as trigeminal neuralgia
Arteriovenous malformations (AVMs), which is an abnormal collection of blood vessels
Acoustic neuroma, a non-cancerous tumour that develops between your inner ear and brain.
Pituitary tumours, which are tumours at the base of your brain (pituitary gland)
The effects of the Gamma Knife radiosurgery will not be immediate but gradual. As radiation treatments are designed to stop the growth of tumours or lesions, you may only see progress over a period of weeks or months.
How do you prepare for a Gamma Knife radiosurgery?
Your doctor will advise you on how to prepare for your Gamma Knife radiosurgery. Some advice may include:
Fasting from food and drinks from midnight before the procedure.
Wearing comfortable, loose-fitting clothes on the day of your procedure.
You should also inform your doctor if you have:
Medications that you are currently taking, in case they may affect the surgical outcomes.
Allergies to shellfish or iodine (if any), as both are chemically related to the dyes that may be used during the procedure.
Implanted medical devices that are in your body, such as a pacemaker, artificial heart valve, aneurysm clips, neurostimulators or stents.
What can you expect in a Gamma Knife radiosurgery?
Gamma Knife radiosurgery generally involves specialised equipment and imaging scans. Usually, only sedation or local anaesthesia is needed. As patients do not have to go under the knife, there is a reduced risk of infection and bleeding.
Most patients do not feel any pain but may feel slight discomfort from the local anaesthesia. A headframe, which is fitted onto patients to prevent any head movement, may also cause slight discomfort.
The procedure itself takes between 15 minutes – 1 hour or more. However, the preparation and planning may take the team several hours.
Before the procedure
The radiosurgery team will attach a lightweight frame to your head with 4 pins. You will receive local anaesthesia where the pins will be placed. The pins will be placed on each side of your forehead and in the back of your head. This frame stabilises your head during the radiation treatment and serves as a reference on where to focus the beams of radiation.
You may feel pressure for a few minutes as the pins are tightened. This sensation will remain until the frame is removed at the end of the entire procedure.
Next, a radiation therapist will take measurements of your head. They will also perform either a computerised tomography (CT) or magnetic resonance imaging (MRI) scan on you, with the head frame in place. If necessary, a small needle may be placed in the back of your hand or in your arm to inject a dye into your blood vessels. This highlights tumours and blood vessels and helps with the planning.
Lastly, the radiosurgery team will review the results of your brain scans to determine the:
The areas to treat
The doses of radiation to administer
How to focus the radiation beams to treat the areas.
This planning process may take 1 – 2 hours. During this time, you can relax in another room. The frame will remain attached to your head.
During the procedure
Once the team is ready to begin your treatment, you will lie on a bed that slides into a Gamma Knife machine that delivers the radiation. Your head frame will be attached to a helmet inside the machine.
You should not feel the radiation or hear noise from the machine. There will be a microphone that allows you to communicate with the team during the procedure. The team will also monitor you closely using cameras from immediately outside the room.
After the procedure
The table will move out of the machine, and the radiosurgery team will return to the room. They will remove the head frame for you. After about 30 minutes, you should not feel much pressure from the head frame.
You may experience minor bleeding and tenderness at the pin sites. You will also be given medications in case you experience headache, nausea or vomiting after the procedure.
You will be monitored in the observation area for up to an hour before being discharged.
Care and recovery after Gamma Knife radiosurgery
On the morning after your procedure, you can remove the bandages on your pin sites. Clean the sites twice a day with hydrogen peroxide or mild soap and water. You can also apply a small amount of antibiotic ointment on the pin sites for 3 – 4 days. Leave the pin sites exposed as they will heal rapidly.
You should wait for 24 hours before washing your hair. Waiting allows the pin sites to heal and prevents infection from developing in the wounds. If there is any bleeding, press on the area with tissue paper for 10 minutes.
Call your doctor if you notice any of the following:
Pin sites feel hot to the touch.
Cloudy or foul-smelling drainage leaking from the pin sites.
Established in Singapore for more than 60 years, Gleneagles Hospital is committed to placing your needs foremost. Our skilled team of neurosurgeons, radiologists and staff are passionate about delivering high-quality, customised healthcare to you.
Our neurosurgeons and radiation oncologists
Gleneagles Hospital's team of neurosurgeons and radiation oncologists are experienced in conducting Gamma Knife radiosurgery to treat brain tumours, AVMs and nerve disorders. Together with our multidisciplinary team of healthcare professionals, we strive to deliver a private and comfortable radiation therapy experience for you.