Gamma Knife is a type of stereotactic radiosurgery used to treat selected problems in the brain. It uses many small radiation beams that meet at a carefully planned target.
Despite the name, there is no knife and no surgical cut. The treatment is called radiosurgery because it treats a small target very precisely.
01 · Understand the examination
About this scan
Common Indications for Gamma Knife
Your doctor may consider Gamma Knife for:
- Small brain metastases.
- Some benign brain tumours.
- Acoustic neuroma or vestibular schwannoma.
- Meningioma in selected cases.
- Arteriovenous malformation (AVM).
- Trigeminal neuralgia in selected cases.
- Small targets near sensitive brain structures.
Is it brain surgery?
No. There is no opening of the skull. Some systems use a head frame fixed to the skull with pins, while others use a mask. Your centre will explain which setup they use.
What happens when I arrive?
The team confirms the target and prepares your head position. If a frame is used, local anaesthetic is given where the pins touch the scalp.
Is there any discomfort?
The radiation is painless. You may feel pressure from a head frame, discomfort from lying still, or anxiety from the setup.
Are there risks?
Risks depend on the target. They can include headache, nausea, scalp soreness, swelling around the treated area, seizures, or delayed radiation effects. Your team should explain warning symptoms before you leave.
Will the tumour disappear immediately?
Usually no. Gamma Knife often works slowly. Follow-up scans may show shrinkage, stability, or reduced activity over time.
02 · Plan ahead
Before your appointment
What exactly does Gamma Knife treat?
It treats a small target inside the head. It is not used for cancers spread throughout the whole body.
How should I prepare?
You may need MRI, CT, blood tests, and a planning review. Tell the team if you take blood thinners, have a pacemaker, have metal implants, or struggle with tight spaces.
How is the treatment performed?
You lie on the treatment couch while the machine delivers focused radiation to the target. You do not feel the radiation.
03 · On the day
During the scan
How long does Gamma Knife take?
The actual treatment may take minutes to a few hours, depending on the number and size of targets. The full visit can take longer because of imaging, planning, frame placement, and recovery.
04 · Important exceptions
Safety and special situations
Can I have Gamma Knife if I am pregnant?
05 · Know the red flags
When to seek urgent help
When should I seek urgent help?
Seek urgent assessment for a first seizure, a prolonged seizure, new weakness, worsening confusion, loss of consciousness, repeated vomiting, or a sudden severe headache. Follow the centre's instructions for frame-pin bleeding, swelling, or signs of infection.
06 · Learn more
Sources and summary
Sources and further reading
Conclusion
Gamma Knife can sound frightening because of the name, but it is a focused radiation treatment, not open brain surgery. Ask whether you will have a frame or mask, how long the day may take, and what symptoms should make you call after treatment.