Gamma Knife surgery is a clinically proven method to treat selected intracranial (within the skull) locations, such as the brain, brain stem or trigeminal nerve. Despite its name, the Gamma Knife icon is not a blade that cuts, but highly sophisticated non-invasive technology that uses radiation to damage targeted tissue in a very precise manner while minimising exposure to healthy surrounding tissues and critical structures. This highly precise and focused treatment is called stereotactic radiosurgery. Stereotactic radiosurgery reduces the risk of potential side effects that might impact normal brain function and your quality of life.
The Gamma Knife is able to reach areas deep in your brain—when it comes to sparing healthy brain and body tissue, no other radiosurgery technique can match it. Preserving tissue helps maintain normal function that can impact quality of life.
The type of stereotactic radiosurgery treatment you receive will depend on your diagnosis and your specific treatment needs. For many conditions, the Gamma Knife treatment can be delivered in a single session and you will be able to leave the same day and be back to your normal daily routines within a day or two.
For some conditions, you may be offered fractionated stereotactic radiosurgery, which divides the total radiation dose over several treatment sessions. Fractionation extends Gamma Knife precision and accuracy to previously challenging tumours, including large lesions or those next to very sensitive areas such as the optic chiasm (where the left and right optic nerves partially cross to the opposite side of the brain).
How does Gamma Knife treatment work?
During Gamma Knife treatment, up to 192 radiation beams are precisely directed to one or several intracranial lesions, so the tissue where the beams intersect receives a concentrated dose of radiation. The source of radiation is cobalt, and the shape and dose of the radiation is optimised to focus on an exact point without damaging healthy tissue or nearby critical structures.
Gamma Knife can be used to treat a number of neurological disorders, including:
- Benign or malignant tumours
- Brain metastases
- Recurrent glioblastomas
- Trigeminal neuralgia
If you are being treated in a single day, you will have a stereotactic frame fitted to your head under local anaesthetic, which allows pinpoint treatment accuracy and prevents your head from moving during your imaging and treatment sessions.
If you are undergoing fractionated treatment over several days, you will be treated using a custom stereotactic face mask. Prior to your first treatment, you will go to your treatment centre to have your mask custom-made for you; the mask is made of breathable material and is heated to become flexible during the fitting process. Once the mask is formed, it will be used in conjunction with a custom-shaped cushion to hold your head still through the process.
After your treatment
Whether you undergo frame-based or mask-based, the ultimate aim is for the radiation treatment to damage the DNA of the targeted cells and prevent them from reproducing. Treatments are designed to stop the growth of tumours or dysfunctional tissue, which means that the effects are observed over a period of weeks or months. Your consultant will stay in contact to assess your progress, which may include follow-up visits and imaging.
As all treatments are delivered as a day case, patients will leave the same day with most returning to routine activities within a day or two.
Side effects
Gamma Knife is so precise that minimal damage occurs to healthy tissues surrounding the treatment target. There may actually be a lower risk if side effects than with other types of radiation therapy.
The Leeds Gamma Knife Centre, within Nova Healthcare, has been treating patients with brain tumours and diseases since 2009. Situated in the heart of Leeds Cancer Centre at St James’s University Hospital, we work in partnership with Leeds Teaching Hospitals NHS Trust to deliver treatment on our Gamma Knife Icon – one of only two in the UK.
