What is Gamma Knife Radiosurgery?
Gamma Knife surgery is a well established method of treating selected targets in the brain. It is sometimes used as a replacement for conventional surgery, but at other times it may be effective in situations where there is no conventional surgical alternative available. Gamma Knife is not a knife in the normal sense of the word. No incisions are made in your head. Instead, very precisely focused beams of radiation are directed to the treatment area in the brain, optimised to hit only the target without damaging surrounding healthy tissue. Gamma Knife surgery offers a safe and effective treatment for more than 77,000 patients worldwide every year. The treatment procedure is simple, painless and straightforward.
How does Gamma Knife Work?
Gamma Knife is a very precise and effective instrument that uses radiation to treat the brain and is often called radiosurgery. Using this method, doctors are able to focus radiation directly, and very precisely, on the target in the brain without affecting surrounding healthy tissue.
Through the use of three-dimensional, computer-aided planning and the high degree of immobilisation of the patient, the treatment can minimise the amount of radiation to surrounding healthy brain tissue. Thousands of radiation beams can be generated with a level of accuracy of more than 0.5mm, about the thickness of a strand of hair. Individually, each radiation beam is too weak to damage the normal tissues it crosses on the way to the target. But when focused precisely on that target, the beams intersect and the combined radiation is sufficient to treat the targeted area.
The Radiation damages the DNA in the cells of the tumour or other abnormality being treated, such that the cells that make up the abnormal tissue targeted can no longer reproduce. Eventually, when these cells come to the end of their natural life span, they find that they are unable to reproduce and replace themselves because the DNA essential to this process is no longer functioning properly. Because Gamma Knife radiosurgery is so accurate, the full dose of radiation can be delivered during a single session, compared with multiple visits for conventional radiotherapy treatments, which use lower doses delivered in fractions (fractionated treatment).
Who determines if Gamma Knife Radiosurgery is appropriate?
A multi-disciplinary clinical team comprising neurosurgeons, clinical oncologists, neuro-radiologists and physicists held at Sheffield Teaching Hospitals NHS Foundation Trust discuss every referral to the Centre to ensure that only suitable patients are accepted for treatment.
All patients that it’s believed may benefit from Gamma Knife surgery will be referred through an established pathway and have a consultation with an appropriately-trained Neurosurgeon who will fully discuss their treatment options.
Is it effective?
Over one million patients worldwide have been treated by Gamma Knife Radiosurgery and thousands of peer reviewed scientific papers have been published demonstrating its effectiveness for benign tumours such as acoustic neuromas, meningiomas, pituitary adenomas, pineal tumours; malignant tumours like metastatic tumours, astrocytomas and glioblastomas and some functional disorders such as Trigeminal Neuralgia. Its use for conditions such as epilepsy and Parkinson’s disease is under investigation.
Patients may be eligible for Gamma Knife Radiosurgery even if they have previously had open brain surgery, radiation therapy or chemotherapy. Results have proven to be superior or comparable to conventional neurosurgery or whole brain radiotherapy, depending on the specific condition treated.
Is it safe?
Gamma Knife Radiosurgery is unique because no surgical incision is performed to “expose” the lesion. Consequently, the risk of surgical complication is greatly reduced bu as with any form of surgical or radiation treatment, there will always be some small risk attached and this can never be reduced to zero. However, in the case of Gamma Knife Radiosurgery this can nearly always be brought down to very low levels – indeed one of the more common reasons for recommending Gamma Knife Radiosurgery is that the overall risk compared to open surgery is frequently much lower. The precise nature and magnitude of any risk will vary with the size, nature and position of the lesion being treated. You should ask your treating doctor to elaborate on the details of this with respect to your own individual situation – they will be more than happy to give you a very full explanation of all that is involved.
What’s involved in a treatment?
What disorders can Gamma Knife treat?
Gamma Knife radiosurgery has been extensively tested and proven effective in treating:
- Acoustic Neuromas
- Vascular disorders
- Trigeminal Neuralgia
- Pituitary Tumours
- Ocular disorders
The Gamma Knife can also be used to treat Arteriovenous malformations. These are currently treated at he Royal Hallamshire or at the Queen Square Radiosurgery Centre, London
What are the advantages of Gamma Knife Radiosurgery?
Gamma Knife radiosurgery has many advantages compared with traditional surgery and other types of radiation treatment.
- Usually only involves a single night’s stay in hospital, and frequently not even that, as opposed to the extended stay often necessitated by surgery
- Offers the prospect of return to work, driving, and other normal social activities within a few days in the vast majority of cases and frequently as soon as the day following treatment
- High levels of effectiveness proven to be comparable or better than other treatment
- More than 77,000 patients treated per year worldwide and an impressive scientific track record with thousands of peer-reviewed articles. No other non-invasive treatment method in this field has greater clinical acceptance.
- Delivers significantly lower dose of radiation to surrounding healthy tissue than conventional fractionated radiation therapy
- The risks of infection, and haemorrhaging are eliminated together with scarring and potential disfigurement that results from conventional neurosurgery.
- The small risk associated with general anaesthesia is eliminated. A mild sedative is occasionally used
- Low risk of post-surgical complications
- An individual who might be a relatively high risk candidate for conventional surgery may be a much safer candidate for GKRS.
- Unlike conventional whole brain radiotherapy Gamma Knife radiosurgery is directed very specifically at the target. This spares most of the adjacent normal brain tissue from exposure to unnecessary excess radiation.
- Unlike conventional radiotherapy which is often delivered over several weeks, GKRS can nearly always be delivered as a single treatment over the course of less than a day. Multiple hospital visits are therefore avoided.
- No hair loss or scarring
What are the complications of Gamma Knife Radiosurgery?
Complications are infrequent or rare compared to conventional surgery. Minor side effects, which generally resolve within a few hours, are sometimes seen but do not usually present the patient with a significant problem. The most commonly reported complications are local pain or swelling at the site of the pin placement and/or headache. The consultant will of course discuss all risks and possible complication with you prior to treatment.
What about the radiation risk?
The dose of radiation is extremely focused to the target in the brain and the dose outside the target is very low.
What is the referral process?
All NHS referrals need to be made to the Sheffield Teaching Hospitals NHS Foundation Trust and follow national service specifications.
For patients wishing to be treated by Gamma Knife as anNHS or private patient you need to discuss this with your specialist and or GP and your referral must come from them. If they feel it is appropriate they will refer you to a specialist at the centre. Your case will then be considered in detail by a multi-disciplinary team of experts to decide if Gamma Knife treatment is suitable for you. Below are step by step instructions on how to be referred for treatment:-
Should you require additional advice and information on how to be referred for Gamma Knife therapy please contact us.
• Step 1: Ask your GP or consultant if your condition is appropriate for Gamma Knife therapy. You can be referred either as an NHS patient or as a private patient.
• Step 2: If Gamma Knife is an appropriate treatment option for your condition, ask your GP or consultant for a referral to The Gamma Knife Centre at QSRC.
• Step 3: Ask your GP or consultant to complete the Gamma Knife referral forms available here on this web-site, or to write a referral letter.
If you have any questions please contact us.
Will the Gamma Knife procedure hurt?
The treatment is painless but the frame fitting undoubtedly involves a small degree of discomfort, but most patients tolerate it remarkably well. The application of the head frame requires the administration of four small injections to administer local anaesthetic (similar to having a dental treatment) in order to numb the sites where the 4 pins are to be used to secure the frame. The whole procedure takes about 5 – 10 minutes during which you may experience some minor discomfort from the wearing of the head frame but will quickly get used to this.
How will I feel following treatment?
Some tiredness, discomfort at the pin sites and a mild headache are quite common and mild nausea may also occur during the first 48 hours following treatment. However, the effects of the treatment are minor in the vast majority of cases and patients can normally return home on the day of treatment and return to normal activity almost immediately.
Following treatment when can I go back to work?
There is no reason why you should not go back to work the following day if you feel well enough and most people return to work within less than a week.