What is Gamma Knife radiosurgery?

Gamma Knife radiosurgery is an established stereotactic radiosurgery (SRS) technique which is able to deliver large doses of highly precise radiation to treat tumours, vascular malformations and other abnormalities of the brain. Despite its name, this treatment does not involve a knife or surgery. It is often used to treat both benign (non-cancerous) brain conditions and metastatic (secondary) cancer deposits in the brain.

At the GenesisCare Centre for Radiotherapy at Cromwell Hospital in London, SRS treatment is delivered using a Gamma Knife® Icon™ machine – an advanced technology using a precise beam of radiation to treat brain tumours. The Gamma Knife uses up to 192 tiny beams of gamma radiation to target the area with sub-millimetre accuracy. This treatment is delivered either in a single session or within a few sessions depending on the condition being treated.

With the Gamma Knife radiosurgery, we are able to minimise the radiation to the surrounding healthy brain tissue and thereby reduce the risk of damage to it.

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If you’d like more information about our specialist Gamma Knife radiosurgery service at Cromwell Hospital in London, just get in touch.

Benefits of Gamma Knife radiosurgery


One of the major benefits of Gamma Knife radiosurgery compared to open surgery is that it is non-invasive. As a result, it usually has minimal complications

Goes further to treat you

Gamma Knife enables us to treat hard-to-reach brain tumours that conventional surgery cannot

Does not leave a mark

Unlike open surgery, you won’t have scars or need to shave your head prior to Gamma Knife treatment and it’s unlikely that you’ll experience any significant hair loss either

Fast recovery

Many Gamma Knife patients can be treated as a day case procedure. You should be able to return to most of your normal activities in 1-2 days compared to 2-6 weeks with open surgery

Limits risks and side effects

You avoid risks such as infection or bleeding that are associated with open surgery. Meanwhile, side effects such as headache and nausea are very rare and temporary

Is Gamma Knife radiosurgery right for you?

We use Gamma Knife radiosurgery to treat a variety of brain conditions, from benign brain conditions to brain metastases (secondary brain tumours). Your consultant will work with a team of consultant neuro-surgeons, neuro-oncologists and neuro-radiologists, as well as other healthcare professionals, to decide if Gamma Knife radiosurgery is the best treatment option for you after careful evaluation of your condition.

Gamma Knife for benign brain conditions

Gamma Knife radiosurgery is a non-surgical radiation therapy and a well-established SRS technique that delivers large doses of highly targeted radiation to treat tumours and benign conditions including:

  • Vestibular schwannoma
  • Pituitary adenoma
  • Meningioma
  • Other skull base tumours
  • Arteriovenous malformation
  • Trigeminal neuralgia
  • Some forms of epilepsy, Parkinson’s disease and tremors

Gamma Knife for metastatic brain tumours

Gamma Knife radiosurgery has significant benefits over conventional whole-brain radiotherapy for metastatic brain tumours, also known as secondary cancer or stage 4 cancer. By limiting radiation to the surrounding healthy brain tissue, we can reduce immediate and late side-effects and hence offer a better quality of life.

However, SRS may not be suitable if:

  • The treatment area includes certain important nerves that could be accidentally damaged by radiation
  • Volume of disease is more than 20cc (roughly this would translate to individual tumour size <3-4cm)
  • If you have uncontrollable disease outside brain

Your Gamma Knife treatment

Here’s what to expect on the day of your Gamma Knife radiosurgery, it’ll involve fitting you with a face mask or head frame, planning and treatment. You’ll be asked to wash your hair before arriving and not to eat or drink anything for four hours, unless you have diabetes.

Gamma Knife side effects

All treatments carry the risk of some side effects, however, you can expect fewer side effects with stereotactic radiosurgery (SRS) than conventional radiotherapy because its greater accuracy means that the risk of damage to healthy brain tissue is lower.*

Not everyone experiences side effects but your risk may be affected by your general health, other treatments you’ve had and the location of your lesion or tumour.

If you do experience some changes after treatment, your care team will advise you on the best way to deal with them.

* Risk of seizures is slightly increased after treatment but usually only affects people who have a history of seizures. Ask your medical team for advice. If you have a seizure for the first time, go straight to your nearest hospital’s accident and emergency department.

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