Gamma Knife surgery

At MQ Health, we adopt a multidisciplinary team (MDT) approach to care for patients needing Gamma Knife surgery.

Our team meets regularly to discuss individual cases and determine the best treatment approach for all patients being treated with the Gamma Knife.

The team includes clinicians from different specialist areas including neurosurgeons, radiation oncologists, medical physicists, radiation therapists and nurses.

At the team meetings, we discuss every case referred and explore all possible treatment options before Gamma Knife treatment is approved.

Our expert team includes:

• Associate Professor John Fuller, Neurosurgeon
• Dr Benjamin Jonker, Neurosurgeon
• Dr Timothy Siu, Neurosurgeon
• Dr Sandy Sampaio, Radiation Oncologist
• Dr Annie Ho, Radiation Oncologist
• Dr Cecelia Gzell, Radiation Oncologist
• Mr Michael Grace, Lead Medical Physicist
• Ms Rebecca Cox, Nurse Unit Leader and Gamma Knife Nurse Coordinator

MQ Neurosurgery is one of the largest academic neurosurgery groups in Australia. Our team includes neurosurgeons and a dedicated neurosurgery research laboratory.

Our researchers are trying to understand the physiological origins and behaviour of a wide range of conditions in order to develop treatments that deliver optimal patient outcomes.

Our Gamma Knife research projects are focused on improving treatment outcomes through non-invasive pathways. One of the ways we do this is through neurovascular simulations.

Some of our current research projects include looking at the use of Gamma Knife therapy combined with pharmaceuticals, and developing simulation software that determines the most effective surgical intervention for neurological conditions.

As leaders in Gamma Knife treatment, we train surgeons and oncologists to develop specialty skills and knowledge in Gamma Knife and the management of cases they would not see anywhere else.

We are always seeking to engage with clinicians dedicated to the pursuit of patient-centred excellence and interested in supporting the teaching and training of students during clinical placements.

Our team also offers opportunities to engage in clinical and/or laboratory research, including formal or honorary appointments with the Faculty of Medicine and Health Sciences (dependant on skills, experience and desired commitment). Contact us to learn more.

Step 1: Before the treatment

Before you have treatment your doctor will explain the entire process to you, and answer any questions you may have. Gamma Knife “surgery” does not require any cutting or shaving of your hair. The nurse will contact you prior to treatment to discuss any further questions or concerns.

Step 2: Fitting of the frame

An essential component to the Gamma Knife treatment procedure is the use of a specialised precision head frame. The head frame performs two important functions. Firstly it allows the doctors to very precisely and accurately pinpoint the target area requiring treatment. Secondly, the frame ensures you remain completely still throughout the procedure. The head frame is attached to your head via four pins using local anaesthetic.

Step 3: Target localisation

Once the head frame has been fitted, a series of tests will be performed to determine the exact size and location of the target area. This includes imaging techniques such as MRI, CT or angiography.

Step 4: Treatment planning

The information gained from the imaging in step 3 is used by your doctors with the assistance of highly trained medical physicists to develop an accurate and customised treatment plan. Every plan is unique and tailored to the specific requirements of each patient.

Step 5: Gamma Knife treatment

Once the treatment plan has been completed by the team of professionals your treatment can begin. With your head frame attached you will be positioned on the treatment couch. The procedure is completely painless (indeed it can be considered boring) and you will remain awake throughout the procedure with the treatment team monitoring you the whole time. The length of the treatment will vary from patient to patient and depends on the size and shape of the target area. The treatment time can be from one to three hours. The entire Gamma Knife procedure – frame on to frame off – therefore takes approximately two to eight hours.

Step 6: After treatment

Following treatment, the head frame and pins will be removed. Generally you will feel no effects of the treatment; however some patients may experience a mild headache or minor swelling from where the frame was attached.

Step 7: Follow up

An appointment will be made for you to see either your treating or referring doctor. Should you have any queries following treatment, please contact your consultant or the nursing staff at Radiation Oncology.

The effectiveness of your Gamma Knife treatment will be evaluated over time. The radiation treatment is designed to stop the growth of tumours or dysfunctional tissue, therefore it may take weeks or even months before the full benefit of the treatment may be realised.

It may be necessary to have follow-up imaging such as MRI or CT to assess your progress over time.

Brochures

• Brochure for Patients
• Brochure for GPs
• Understanding Brain Tumours

Useful Websites

Australian

• Beyondblue
• Brain Tumour Alliance Australia
• Cancer Council Australia
• CanTeen
• Carers Australia

International

• Cancer Research UK
• American Cancer Society

What is Gamma Knife surgery (GKS)?

Gamma Knife surgery (GKS) is a safe, effective and non-invasive procedure that uses radiation to treat conditions in and around 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. The radiation treatment is delivered with great precision to the target tissue within or around the brain, whilst at the same time minimising any dose to surrounding healthy tissue. The name ‘Gamma Knife’ is in some ways misleading – no knife or cutting implement is actually involved at any stage. The term ‘Gamma Knife’ is intended to convey the idea that this radiation treatment is in some ways delivered as though it were an actual knife, because it offers a similar sort of precision and targeting to that offered by actual surgery. It uses radiation in much the same way as a surgeon uses a knife.

Is this treatment right for me?

If you are unsure if Gamma Knife would be a suitable treatment for your condition or you would like to find out more please contact us. Someone will be in touch to tell you more about the treatment and if it is potentially suitable for you. The multidisciplinary Gamma Knife team meet regularly to discuss new cases and are happy to review your scans. There is no cost for this service. The team includes a neurosurgeon, radiation oncologists, medical physicist and nurses. Once your case has been discussed we will be in contact shortly afterwards to let you know if Gamma Knife is an option for you or if not we may be able to advise on other treatments. It can be a very valuable second opinion free of charge.

How does Gamma Knife work?

Radiation damages the DNA in the cells of the tumour or other abnormality being treated, such that the cells that make up the targeted tissue can no longer divide. Eventually, when these cells come to the end of their natural life span, they find that they are unable to divide and replace themselves because the DNA essential to this process is no longer functioning properly. Some lesions which are very inactive in terms of cell function may take up to 2 or 3 years or more to respond to treatment – this is typically the case for instance with blood vessels, and arterio-venous malformations (AVM) which usually resolve over this sort of time period.

Is Gamma Knife surgery safe?

Yes – in terms of the risk of damage to tissue around the target area. GKS risks can nearly always be brought down to very low levels – one of the more common reasons for recommending GKS is that the overall risk compared to open surgery is frequently much lower. This is sometimes so much the case that the surgical alternative may actually carry a higher overall risk than that of the condition being treated, thereby rendering it effectively inoperable other than by radiosurgery. 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. 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.

What are the possible complications of Gamma Knife surgery?

Serious complications of GKS are very unusual. Minor side effects, which generally resolve within a few hours, are sometimes seen and do not usually present the patient (or the doctor) with a significant problem.

It is fair to say that the large majority of patients suffer no side effects whatsoever, apart perhaps from a feeling of being a bit tired and ‘washed out’ at the end of a busy day’s treatment!

We tend to think of complications in terms of those which may occur early i.e. soon after treatment, and those which can occur at a later stage, some weeks or months following GKS:

Common:

• some local discomfort of the scalp relating to the pin sites which are used to fix the frame – resolves within a few hours, almost certainly by the following morning
• numbness of the scalp around pin sites may occur which resolve over a day or two
• headache – again usually mild, resolving rapidly
• mild nausea
• delayed complications.

Uncommon:

• visual loss
• hearing loss
• epileptic seizures
• radiation effects on surrounding brain tissue
• hair loss (very localised) adjacent to treated area.

These complications tend to relate only to treatment for particular conditions. Your treating doctor will be able to elaborate on the details of this with respect to your own individual situation.

What are the potential benefits of Gamma Knife surgery over conventional surgical techniques?

• The risks of infection, haemorrhage and spinal fluid leakage are eliminated, as is the scarring and potential disfigurement that results from conventional neurosurgery.
• The small risk associated with general anaesthesia is also eliminated. A mild sedative is occasionally used.
• GKS is a day procedure except in occasional circumstances.
• GKS sometimes can be used in conjunction with conventional surgery, usually taking the place of the more risky component of the latter. In other words, where conventional surgery is absolutely required, its risk can be reduced by partially substituting GKS as a ”boost” to perform the final part of the job.
• An individual who might be a relatively high risk candidate for conventional surgery may be a much safer candidate for GKS.
• Unlike whole brain radiotherapy, GKS is directed very specifically at the target. This spares most of the adjacent normal brain tissue from exposure to unnecessary excess radiation.
• “Fractionation” is not required – unlike radiotherapy (such as Linac SRS which may require fractionation), which is often delivered in many fractions over several weeks, GKS can nearly always be delivered as a single treatment over the course of less than a day. Multiple hospital visits are therefore avoided.
• As a day case treatment GKS offers the prospect of return to work, driving, and other normal social activities within a few days in the vast majority of cases. This is frequently as soon as the day following treatment.
• Established effectiveness over 50 years of experience worldwide, with a very low rate of complications.

Will the Gamma Knife procedure hurt?

The stereotactic frame is fitted under local anaesthesia. This involves the administration of 4 small injections around the circumference of the head, in order to numb the sites where the 4 pins are to be used to secure the frame.

The experience of these is the same as when visiting the dentist for the purpose of having a tooth put to sleep for filling. The same local anaesthetic drug is used in both instances. Very quickly, after a brief stinging sensation, these areas will go numb.

The frame is then attached. As the pins are secured you will feel a strange “pressure” sensation which quite soon passes. The whole procedure takes about 5 – 10 minutes, and after the frame is fitted you will gradually get used to the sensation. After a short while you will no longer feel this, and you will almost forget that the frame is there at all!

Frame fitting involves a small degree of discomfort, but most patients tolerate it remarkably well, and tend to comment that it was much preferable to the idea of having a major surgical procedure performed.

At the end of the procedure the frame is removed. This only takes a minute or two, and is not  traumatic. Some patients experience headaches after frame removal which can be treated with simple pain relief.

Will I be radioactive?

No. All radiation stays within the treatment room. The Gamma rays used in the treatment do not remain in the body.

Will I have swelling or oedema?

In the postoperative period some tumours may swell a little as a result of being injured by a dose of radiation. This may show as a slight increase in apparent size of the tumour as assessed by MRI or CT scanning at about 6-9 months post treatment.

This appearance must not be misinterpreted as tumour growth. It is self-limiting, and will soon be followed by reduction back to original size, or even smaller.

If this temporary swelling (which actually indicates that the treatment is starting to work) causes any symptoms, then a short course of steroids or other medication is sometimes used to treat the swelling.

Will I lose my hair?

The vast majority of patients have no risk whatsoever of losing any hair at all. Furthermore, even in those few cases where hair loss is a possibility, such hair loss will never involve the entire scalp – as typically happens with whole brain radiotherapy.

Only a small number of patients will have tumours sufficiently close to the scalp to carry the risk of any hair loss at all. If a lesion to be treated is very close to the inside of the skull, it is possible that enough radiation will be delivered to the scalp to cause a patch of hair the size of a 10 or 20 cent coin to be lost. This hair usually grows back, though it may be a little lighter in colour and finer in texture than previously.

How will I feel following treatment?

Most patients feel just as well as they did at the beginning of the day. Some tiredness is quite common, especially if the treatment has occupied most of the day. A little discomfort at the pin sites and a mild headache are also quite common – this may persist for up to a day or two. Mild nausea may also occur during the first 48 hours following treatment. Mild anti-nausea and headache medication is routinely prescribed for patients who may require it. Patients are observed for one to two hours post treatment.

When can I go back to work following treatment?

As soon as you feel well enough. There is no reason why you should not go back to work the following day – some patients have even been known to return to work later the same day, but you should not feel pressured to return to work too quickly. It is fair to say that most people return to work within less than a week.

How soon can I travel (by motor vehicle, bus, train, plane) following treatment ?

Again, as soon as you feel well enough. There is no reason why you could not travel the following day, or even some time later on the actual day of treatment. Any driving restrictions already in place will continue to apply.

Designed specifically for and dedicated to the brain, Gamma Knife surgery is widely recognised as the gold standard in stereotactic radiosurgery. Advantages of Gamma Knife surgery include:

• non-invasive and highly targeted with minimal dose to surrounding normal brain
• avoids complications associated with surgery and Whole Brain Radiation Therapy (WBRT) including white matter changes and neurocognitive decline
• less dose to normal brain and body compared to other radiosurgery devices
• clear clinical advantages and superior outcomes for certain indications (for example, SRS with Gamma Knife low dose to cochlear preserves serviceable hearing in most patients with an acoustic neuroma)
• offers clinician new possibilities to treat cancerous and non-cancerous brain conditions
• single-session treatment
• no cessation of systemic treatment, and ability to maintain drug dosing parameters
• permits the clinician to scan, plan and treat in a single session – optimal efficiency at low cost
• fewer side effects than standard radiotherapy (less fatigue, no hair loss)
• single session treatment completed generally in one day means less burden on patient and carers
• most extensive clinical evidence base with over 2,500 peer-reviewed publications including numerous papers describing the utility of the Gamma Knife surgery for multiple metastases.

Conditions for which Gamma Knife surgery is considered most effective are:

• malignant and benign brain tumours, including metastases and glial tumours, acoustic neuromas, meningiomas
• vascular abnormalities, including arteriovenous malformations
• functional disorders, including trigeminal neuralgia.