Gamma Knife Radiosurgery in Singapore: A Comprehensive Guide

Living with a brain condition can be overwhelming. Whether you’ve been diagnosed with a brain tumour, arteriovenous malformation (AVM), or trigeminal neuralgia, the prospect of brain surgery may feel daunting. Gamma Knife radiosurgery offers an alternative approach that treats brain conditions without traditional open surgery. This non-invasive treatment delivers precisely targeted radiation to specific areas of the brain whilst minimising exposure to surrounding healthy tissue.

In Singapore, Gamma Knife radiosurgery is a commonly used treatment option for selected neurological conditions. This guide explains what the procedure involves, who may benefit from it, and what to expect during the treatment process. Understanding these aspects can support informed discussions with a neurosurgeon.

Dr Teo Kejia (张哿佳医生)

Senior Consultant Neurosurgeon

MBBS (SG)MRCS (Edin)IFAANSFAMS (Neuro Surg)FRCS Ed (Neuro Surg)

Overview Candidates Approaches Treatment Recovery Benefits Risks Cost FAQS Conclusion

What is Gamma Knife Radiosurgery?

Gamma Knife radiosurgery is a form of stereotactic radiosurgery (SRS) that uses highly focused beams of gamma radiation to treat abnormalities within the brain. Despite its name, Gamma Knife radiosurgery does not involve any cutting or incisions. Instead, multiple low-dose radiation beams are directed from different angles and converge precisely at a defined target. This creates a concentrated therapeutic dose at the treatment site while limiting radiation exposure to surrounding brain tissue.

The treatment has evolved significantly over time and is now widely used in neurosurgical practice.

Gamma Knife radiosurgery is often considered for brain lesions that are difficult to access through conventional surgery, or for patients who may not be suitable candidates for open neurosurgical procedures due to medical factors.

Conditions commonly treated with Gamma Knife radiosurgery include:

Brain tumours (both benign and malignant)
Arteriovenous malformations (AVMs, abnormal tangles of blood vessels in the brain)
Trigeminal neuralgia (a nerve disorder causing severe facial pain)
Acoustic neuromas (non-cancerous tumours affecting the hearing and balance nerve)
Pituitary adenomas (tumours of the pituitary gland)
Selected movement disorders

The precision of Gamma Knife radiosurgery allows treatment of very small targets, sometimes only a few millimetres in size, while minimising radiation to nearby structures. Many patients are able to return home on the same day and resume normal activities shortly after treatment, depending on individual circumstances.

Ideal Candidates

Gamma Knife radiosurgery is not suitable for every brain condition. Careful patient selection is essential to ensure safety and effectiveness. A neurosurgeon will assess several factors before recommending this treatment. Gamma Knife radiosurgery may be appropriate for patients with the following characteristics:

Small to medium-sized brain tumours, including meningiomas ( a tumour that grows from the membranes that surround the brain and spinal cord), acoustic neuromas (benign tumours affecting the hearing and balance nerve), pituitary adenomas (benign growths of the pituitary gland), and brain metastases (cancers that have spread to the brain from other parts of the body).
AVMs, particularly when they are small to moderate in size or located in areas that are difficult to access with open surgery. –
Trigeminal neuralgia, when symptoms are not adequately controlled with medication or other treatments.
Patients who may not be suitable for open brain surgery due to age, underlying medical conditions, or the location of the brain lesion.
Recurrent tumours, including those that persist or return after previous surgery or radiation therapy.
Multiple brain metastases arising from cancers originating elsewhere in the body.
Selected movement disorders, such as essential tremor (involuntary shaking), in appropriately evaluated cases.
Overall medical fitness to tolerate the procedure and any required sedation.

Contraindications

The suitability of Gamma Knife radiosurgery depends on multiple factors, including the size, location, type of lesion, and overall health considerations. A thorough assessment by a qualified healthcare professional is required to determine whether this treatment is appropriate. Our neurosurgeon will review imaging studies, medical history, and treatment goals to provide personalised recommendations based on individual needs. Gamma Knife radiosurgery may not be recommended in the following situations:

Large lesions, which may require radiation doses that increase the risk of damage to surrounding brain tissue. –
Lesions causing significant mass effect, where pressure on the brain or associated swelling requires urgent surgical decompression (a procedure that relieves pressure and swelling by removing part of the skull or tumour).
Pregnancy, due to potential risks from radiation exposure to the developing foetus.
Certain implanted medical devices, such as specific pacemakers, may interfere with treatment planning or delivery.
Inability to tolerate head frame placement or remain still during the procedure.
Previous high-dose radiation to the same region of the brain, which may limit safe retreatment.
Conditions requiring tissue diagnosis, where a biopsy (removal of a tissue sample) is necessary to confirm the diagnosis before treatment.

Treatment Techniques & Approaches

Gamma Knife Technology

Gamma Knife radiosurgery is a non-invasive treatment system that uses highly focused beams of gamma radiation to precisely target specific brain conditions. The system contains multiple sources of radioactive cobalt, arranged in a helmet-like structure. These sources emit gamma rays that are shaped and directed using a collimator system, which controls the size and path of each beam.

During treatment, all radiation beams converge at a defined target point within the brain. This convergence creates a high therapeutic dose at the target while each individual beam delivers only a low dose as it passes through surrounding healthy tissue. This design allows effective treatment of the lesion while minimising radiation exposure to adjacent brain structures.

Modern Gamma Knife systems incorporate automated positioning and advanced control systems. These features enable highly precise treatment delivery and allow multiple targets to be treated within a single session, making the technology suitable for patients with several small lesions.

Stereotactic Frame vs Frameless Approaches

Frame-based stereotactic radiosurgery involves attaching a lightweight metal frame to the patient’s head using a small number of pins under local anaesthesia. The frame serves as a stable reference for imaging and treatment, ensuring high positional accuracy. It remains in place throughout imaging, treatment planning, and radiation delivery.
Frameless approaches use a custom-fitted mask combined with image-guided positioning to localise the target. While frameless systems may be more comfortable for some patients, frame-based Gamma Knife radiosurgery continues to offer a high level of precision and remains a commonly used approach, particularly for small or critically located lesions.

Treatment Planning Technology

Treatment planning is performed using specialised computer software that analyses MRI and CT scans to generate a three-dimensional map of the target lesion and surrounding brain structures. Our neurosurgeon works with a multidisciplinary team to design a treatment plan that delivers the prescribed radiation dose to the target while minimising exposure to critical structures such as the optic nerves, brainstem, and hippocampus. This planning process allows the radiation dose to be shaped precisely to match the size and contour of irregularly shaped lesions, supporting both treatment accuracy and safety.

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The Treatment Process

Pre-Treatment Preparation

Before undergoing Gamma Knife radiosurgery, the neurosurgeon will conduct a comprehensive consultation. This discussion covers the diagnosis, available treatment options, expected outcomes, and potential risks. A review of medical history, current medications, and known allergies is also performed to support safe treatment planning.

In the weeks before treatment:

MRI scans and, in some cases, CT scans are performed to accurately identify and localise the target lesion.
Blood tests may be arranged to assess overall health and suitability for the procedure.
The medical team should be informed of all medications being taken, particularly blood thinners (medications that reduce blood clot formation)
Arrangements should be made for someone to accompany the patient home after treatment

On the day before treatment:

Follow any fasting instructions provided, especially if sedation is planned
Wash your hair without using conditioner, styling products, or hairspray
Wear comfortable, loose-fitting clothing

During the Procedure

Gamma Knife radiosurgery is usually completed in a single day as an outpatient procedure. The treatment process typically includes the following steps:

Stereotactic Frame Placement (approximately 30 minutes): The procedure begins with the placement of a stereotactic frame, a lightweight device that keeps the head still and ensures accurate targeting of radiation. After cleaning the scalp at four pin sites, local anaesthetic is applied to numb these areas. The frame is then secured in place. A sensation of pressure may be felt, but pain is uncommon. Mild discomfort or headache at the pin sites can occur.
Imaging (approximately 1-2 hours): With the frame in position, MRI and, if needed, CT scans are performed. These images provide precise anatomical information required for treatment planning. Remaining still during imaging is important, and communication with the care team is maintained throughout.
Treatment Planning (approximately 1-3 hours): Using the imaging data, the surgeon and the multidisciplinary team develop a personalised treatment plan. This involves determining the number of radiation beams, their angles, and the duration of exposure needed to deliver an effective dose to the target while minimising radiation to surrounding brain tissue.
Radiation Delivery (duration varies): During treatment, the patient lies on a treatment couch with the head positioned within the Gamma Knife unit. Radiation delivery is typically painless and not felt. The length of treatment depends on the complexity of the plan and the number of targets treated.

Immediate Post-Treatment

After treatment is completed, the stereotactic frame is removed. Small dressings are applied to the pin sites. Common short-term effects may include:

Mild headache or tenderness at the pin sites
Temporary swelling at frame attachment points
Fatigue

Most patients rest briefly in a recovery area before being discharged on the same day. It is recommended that someone accompany the patient home, and driving should be avoided on the day of treatment. Follow-up instructions and appointments will be provided by the neurosurgeon.

Recovery & Aftercare

First Hours

The immediate recovery period after Gamma Knife radiosurgery is usually uncomplicated, and most patients are able to return home on the same day.

Pain management:

Mild to moderate headache at the pin sites (where the stereotactic frame was attached) is common and typically responds well to paracetamol or prescribed pain medication.
Ice packs may help reduce localised swelling at the pin sites.
Avoid rubbing, scratching, or applying pressure to the pin site areas.

Activity and rest:

Rest at home for the remainder of the treatment day.
Temporary fatigue is common.
Light activities around the house are generally acceptable.
Avoid strenuous physical activity during this period.

What to watch for:

Contact the clinic promptly if you experience any of the following:
Severe or worsening headache does not improve with medication
Signs of infection at pin sites, such as increasing redness, warmth, swelling, or discharge
Persistent nausea or vomiting
Vision changes or new neurological symptoms, including numbness, weakness, or difficulty speaking
Fever

First Week

During the first week following Gamma Knife radiosurgery, recovery continues steadily for most patients.

Pin site care:

Keep the pin sites clean and dry.
Dressings can usually be removed after one to two days.
Hair washing is typically allowed after a couple of days, using gentle care.
Any remaining pin site discomfort usually resolves within a few days.

Daily activities:

Many patients are able to work and perform normal daily activities within a few days.
Driving can usually be resumed within one to two days, provided you feel well and alert.
Avoid swimming or submerging the pin sites in water for approximately one week.

Follow-up:

A follow-up appointment will be scheduled to assess recovery and address any concerns.
Prescribed medications, such as corticosteroids (anti-inflammatory medications used to reduce swelling), should be taken exactly as directed.

Long-Term Recovery

The therapeutic effects of Gamma Knife radiosurgery occur gradually over time rather than immediately.

Expected timeline of effects:

Brain tumours: Changes may take several months to become visible on imaging. Some tumours shrink, while others stabilise and stop growing.
AVMs: Complete closure often takes several years, with interim imaging used to monitor progress.
Trigeminal neuralgia: Pain relief may begin within days to weeks, with maximum improvement often occurring over several months

Follow-up imaging:

Regular MRI scans are used to monitor treatment response. The timing and frequency of imaging depend on the condition treated and individual clinical factors, and may initially be more frequent before transitioning to annual reviews.

Ongoing care:

Continue regular medications unless advised otherwise by the doctor.
Attend all scheduled follow-up appointments.
Inform the healthcare team promptly of any new or worsening symptoms.

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Clinical Considerations of Gamma Knife Radiosurgery

Gamma Knife radiosurgery is a recognised treatment with several important clinical considerations:

Non-Invasive Procedure

The treatment is performed without surgical incisions or any part of the skull.
Precise Targeting

Specialised technology directs radiation to the specific lesion while minimising exposure to surrounding healthy brain tissue.
Recovery Observations

As an outpatient procedure, most patients can go home the same day and resume normal activities sooner than with traditional open surgery.
Reduced Surgical Risk

Being non-invasive, it avoids risks common in open surgery, such as infection or postoperative bleeding.

The suitability and expected outcomes depend on the lesion’s size and location, as well as your overall health. The neurosurgeon will evaluate these factors to provide personalised guidance.

Common Side Effects

Like all medical treatments, Gamma Knife radiosurgery can cause side effects. Most are temporary and manageable:

Headache: Mild to moderate headache at the sites, usually resolving within a few days.
Fatigue: Feeling tired for several days after treatment is common.
Scalp tenderness: Discomfort at frame attachment points is generally brief.
Nausea: Occasional nausea may occur, especially with lesions near sensitive brain areas.
Temporary swelling: Some swelling around the treated area can occur and is often managed with corticosteroids.
Hair loss: Localised hair loss may happen if radiation passes through hair-bearing scalp areas, usually temporary.

Rare Complications

More serious complications are uncommon but possible:

Radiation necrosis: Damaged tissue at the treatment site may cause swelling or neurological symptoms (weakness, numbness, or changes in coordination). This can often be managed with medication.
Worsening neurological symptoms: Temporary or, rarely, permanent changes in function may occur depending on lesion location.
Cranial nerve effects: Small risk of nerve dysfunction when treating lesions near cranial nerves. For example, hearing changes may occur during acoustic neuroma treatment.
Cyst formation: Fluid collection at the treatment site may develop in some cases.
Secondary radiation effects: Extremely rare long-term changes in surrounding tissue due to radiation exposure.

The likelihood of complications depends on the size, location, and type of lesion being treated. Our neurosurgeon will review your specific risks during consultation. The precision of Gamma Knife technology, careful treatment planning, and experienced neurosurgical care all help minimise these risks.

Cost Considerations

The cost of Gamma Knife radiosurgery in Singapore varies depending on several factors:

Complexity of the treatment plan: Lesions with irregular shapes or multiple targets may require more detailed planning and longer treatment time.
Hospital and facility charges: This includes use of the Gamma Knife system and advanced imaging equipment.
Professional fees: Fees for the medical team, such as a neurosurgeon, radiation oncologist, and medical physicist (a specialist who ensures radiation is delivered accurately and safely).
Pre-treatment consultations and imaging: MRI and CT scans are required for treatment planning.
Post-treatment follow-up: Follow-up consultations and imaging studies to monitor recovery and treatment response.

When evaluating cost, it is also helpful to consider the broader aspects of Gamma Knife radiosurgery. Its non-invasive nature means no surgical incisions, shorter recovery time, reduced time away from work, and avoidance of certain risks and hospital stays associated with open surgery.

During your consultation, our neurosurgeon will provide a personalised cost estimate based on your condition and treatment plan, helping you make informed decisions and plan your care with clarity.

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Frequently Asked Questions

Is Gamma Knife radiosurgery painful?

The treatment itself is not painful, as you cannot feel the radiation. The most uncomfortable part for many patients is the placement of the stereotactic frame. Local anaesthetic is used at the four pin sites on the scalp, so you may feel pressure rather than sharp pain. Mild headache or tenderness at these sites after the procedure is common and usually responds well to simple pain relief. Overall, most patients tolerate the process well.

How long does the entire Gamma Knife procedure take?

You should expect to spend most of the day at the treatment facility. Frame placement typically takes about 30 minutes. Imaging and treatment planning take several hours, during which you can rest. The radiation delivery itself varies in duration depending on the complexity of your treatment plan. Most patients are able to go home the same day.

How effective is Gamma Knife radiosurgery for brain tumours?

Effectiveness depends on the type, size, and location of the tumour. For many benign tumours, such as meningiomas and acoustic neuromas, Gamma Knife radiosurgery can achieve good tumour control, meaning the tumour stops growing or gradually shrinks. For brain metastases, it can be effective in controlling treated lesions. Our surgeon will discuss expected outcomes for your specific condition and provide realistic guidance based on current evidence and your individual circumstances.

Will I lose my hair after Gamma Knife treatment?

If hair loss occurs, it is usually limited to small areas where radiation enters the scalp and is often temporary. Due to the precise targeting of Gamma Knife radiosurgery, hair loss is generally minimal compared to conventional whole-brain radiation therapy. Many patients experience no noticeable hair loss at all.

Can Gamma Knife radiosurgery be repeated if my condition returns?

In some cases, yes. Repeat Gamma Knife treatment may be considered depending on factors such as the location of the lesion, the radiation dose previously delivered, and the time interval since the initial treatment. For certain conditions, including brain metastases, patients may undergo more than one session over time to treat new or recurrent lesions. Each case is assessed individually.

How does Gamma Knife compare to traditional brain surgery?

Gamma Knife radiosurgery and traditional neurosurgery serve different purposes and are often complementary.

Gamma Knife radiosurgery:

Non-invasive, with no surgical incisions
Does not require general anaesthesia
Shorter recovery time
Suitable for selected deep-seated or multiple lesions

Traditional brain surgery:

Allows immediate removal of larger tumours
Provides tissue for diagnosis
Can rapidly relieve pressure on surrounding brain structures

The most appropriate approach depends on your specific condition, and in some cases, both treatments may be used at different stages.

What happens if Gamma Knife treatment doesn’t work?

The effects of Gamma Knife radiosurgery develop gradually and are assessed over months or even years, depending on the condition treated. If the response is inadequate, alternative options may include open surgery, repeat radiosurgery, other radiation techniques, or medical treatment. Regular follow-up imaging allows our medical team to monitor progress and adjust the treatment plan if needed.

Are there any long-term side effects I should be aware of?

Most patients experience minimal long-term side effects. In a small number of cases, delayed effects such as radiation necrosis (damage to treated tissue) may occur months to years after treatment. There is also a very rare risk of radiation-related changes over the long term. Modern Gamma Knife technology and careful planning help minimise these risks, and regular follow-up imaging is used to monitor for any delayed effects.

Conclusion

Gamma Knife radiosurgery is an established treatment option for selected brain conditions in Singapore. Its non-invasive nature, high precision, and long track record make it a valuable alternative to traditional brain surgery for suitable patients. For conditions such as brain tumours, AVMs, trigeminal neuralgia, and other treatable disorders, understanding available treatment options is an important first step in your care journey.

Treatment outcomes depend not only on advanced technology but also on careful patient selection and specialist expertise. With appropriate evaluation and planning, Gamma Knife radiosurgery may provide effective treatment while minimising disruption to daily life and allowing a relatively quick return to normal activities.

If you or a loved one has been diagnosed with a condition that may be suitable for Gamma Knife radiosurgery, a consultation with a qualified neurosurgeon can help clarify whether this approach is appropriate and what to expect from treatment.

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If you are considering Gamma Knife radiosurgery, schedule a consultation with our neurosurgeon to discuss your condition, treatment options, and personalised care plan.

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Dr Teo Kejia (张哿佳医生)

Senior Consultant Neurosurgeon

MBBS (SG)●MRCS (Edin)●FAMS●FRCS Ed●IFAANS

Dr Teo Kejia is a Senior Consultant Neurosurgeon and Medical Director at Precision Neurosurgery, with more than 15 years of clinical experience.

Dr Teo has extensive knowledge and experience in the field of neurosurgery, with a particular focus on complex brain tumour procedures. He is adept in employing advanced surgical techniques, including brain mapping and awake brain surgery, especially for treating gliomas and glioblastomas. His expertise extends to neuro-oncology, encompassing both brain and spinal tumours, as well as neurovascular and skull base surgery.

Additionally, Dr Teo offers treatment for a range of neurological conditions, such as traumatic head injuries, intracerebral aneurysms, and degenerative spine disorders, which include neck and back pain. He is also proficient in managing ischemic and haemorrhagic strokes, hydrocephalus, trigeminal neuralgia, and hemifacial spasm.

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