Cancer patients and those close to them are often suddenly flooded with a vocabulary of terms they never wanted to know. Below are brief answers to our most often asked questions, to help demystify the choices along the way.
All these questions should always be discussed with a specialist before any decisions are made.
What is radiotherapy?
Radiotherapy (also called radiation therapy) is one of the most effective treatments for cancer. It uses carefully targeted high-energy radiation to damage the DNA of cancer cells, preventing them from growing and dividing while protecting as much healthy tissue as possible.
More than half of people diagnosed with cancer will receive radiotherapy during their treatment. Depending on the type of cancer and the profile of each patient, it may be used to aim for any of the following:
* cure cancer
* reduce the chance of cancer returning after surgery
* shrink a tumour before surgery
* treat cancer that has spread
* relieve symptoms like pain and improve quality of life.
Modern radiotherapy uses advanced imaging, computer planning and highly accurate treatment delivery to maximise tumour control while reducing side effects.
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How does radiotherapy work?
Radiotherapy damages the DNA inside cancer cells. Unlike healthy cells, cancer cells are less able to repair this damage.
Over time the damaged cancer cells die and the body naturally removes them. Depending on the cancer, the tumour may shrink over weeks or months after treatment has finished.
Although healthy tissues also receive a small amount of radiation, they usually recover much more effectively than cancer cells.
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What are the side effects?
Side effects depend on the part of the body being treated.
Many patients continue working and carrying out their normal activities throughout treatment.
Common side effects include:
* tiredness
* skin irritation
* temporary soreness
* changes specific to the treatment area.
Most side effects improve after treatment finishes. Your treatment team will discuss the possible side effects before treatment begins and provide support throughout your care.
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What are the different radiotherapy machines?
Modern radiotherapy machines are designed to deliver radiation safely and accurately to treat cancer and certain non-cancerous conditions. The most appropriate technology depends on the type of cancer, its location, and your individual treatment goals.
The three main types of radiotherapy machines are:
* Linear Accelerators (LINACs) – These are the most commonly used radiotherapy machines worldwide. Modern LINACs treat a wide range of cancers and many are equipped to deliver highly precise stereotactic radiotherapy (SABR/SBRT) and stereotactic radiosurgery (SRS).
* Gamma Knife® – A specialised stereotactic radiosurgery system designed exclusively for conditions within the brain, including brain metastases, meningiomas, vestibular schwannomas, arteriovenous malformations (AVMs) and trigeminal neuralgia.
* CyberKnife® – A robotic stereotactic radiotherapy system that can treat both brain and body tumours. It uses real-time image guidance and, for selected cancers, can track tumour movement during treatment to maintain accuracy.
Modern stereotactic radiotherapy systems are capable of sub-millimetre treatment accuracy. Depending on the tumour location, some treatments may be planned with no additional margin around the visible tumour (a 0 mm planning target volume margin), while others require a small margin to account for normal movement and treatment uncertainties. The appropriate margin depends on the cancer being treated, the imaging used and the technology available.
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What does radiotherapy cost?
Radiotherapy is heavily subsidised in Australia, with patients paying 10-20% of the total cost of their treatment at private care centres.
As it is usually an outpatient treatment, it is not covered by private health funds and there is an out of pocket cost for private care.
Before treatment begins, we provide a clear explanation of the expected out of pocket costs.
SABR (SBRT) Frequently Asked Questions
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What is SABR?
Stereotactic Ablative Body Radiotherapy (SABR), also known as Stereotactic Body Radiotherapy (SBRT), is one of the most advanced forms of radiation therapy available.
Unlike conventional radiotherapy, which is usually delivered over several weeks, SABR delivers very high doses of radiation with exceptional precision over just 1–8 treatments. This allows doctors to destroy cancer cells while minimising radiation exposure to surrounding healthy organs.
SABR combines advanced imaging, sophisticated treatment planning and highly accurate treatment delivery to target tumours with millimetre precision.
It is most commonly used for:
* Early-stage lung cancer
* Prostate cancer
* Liver tumours
* Kidney cancer
* Adrenal tumours
* Pancreatic cancer (in selected patients)
* Spine tumours
* Oligometastatic cancer (where cancer has spread to only a few sites)
For many patients, SABR offers outcomes comparable to surgery while avoiding an operation, hospital stay and lengthy recovery.
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Is SABR the same as SBRT?
Yes.
The terms SABR (Stereotactic Ablative Body Radiotherapy) and SBRT (Stereotactic Body Radiotherapy) describe the same treatment.
In Australia and the United Kingdom, the term SABR is more commonly used because it reflects the aim of delivering a high enough dose to completely destroy (ablate) the tumour.
In North America, the term SBRT is more widely used.
Although the names differ, the treatment technique is the same.
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How is SABR different from standard radiotherapy?
The biggest differences are precision, dose and treatment duration.
Traditional radiotherapy usually delivers smaller daily doses over several weeks. SABR delivers much higher doses during each treatment, allowing the entire course to be completed in only a few sessions.
Compared with conventional radiotherapy, SABR offers:
* Greater treatment precision
* Better protection of nearby healthy organs
* Fewer treatment visits
* Higher biological doses to the tumour
* Excellent local tumour control for many cancers
Because of the high doses used, SABR requires meticulous planning, advanced imaging and strict quality assurance.
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Which cancers can be treated with SABR?
SABR is suitable for many cancers, although not every patient is a candidate.
Common indications include:
* Early-stage lung cancer
* Prostate cancer
* Kidney cancer
* Liver cancer
* Adrenal metastases
* Lung metastases
* Liver metastases
* Spine metastases
* Lymph node metastases
* Pancreatic cancer in selected cases
* Oligometastatic cancer
SABR is also increasingly being used for carefully selected recurrent cancers.
Whether SABR is appropriate depends on the tumour’s size, location, movement during breathing, previous treatments and your overall health.
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Who is suitable for SABR?
SABR is most appropriate for patients with:
* Small, well-defined tumours
* Limited numbers of tumours
* Tumours that can be accurately targeted
* Good overall health
* Tumours located where surrounding organs can be safely protected
Many patients choose SABR because they wish to avoid surgery, while others may have medical conditions that make surgery too risky.
Every patient should undergo an individual assessment by a radiation oncologist experienced in SABR before treatment is recommended.
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What is oligometastatic cancer?
Oligometastatic cancer refers to cancer that has spread to only a small number of sites, typically between one and five tumours but are doing research to see if there really is a limit to number of sites (link, link).
Research suggests that some patients with oligometastatic disease benefit from SABR.
Treating all visible sites of disease may improve survival, maintain quality of life, and reduce the need for additional systemic therapy.
Whether SABR is appropriate depends on the type of cancer and your overall treatment plan.
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Can SABR be repeated?
Sometimes.
If a new tumour develops or cancer returns in a different location, another course of SABR may be possible.
Whether repeat treatment is appropriate depends on:
* The previous radiation dose
* The location of the new tumour
* Nearby organs
* The time since previous treatment
* Your overall health
Each situation requires careful individual assessment.
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Which machine is best for SABR?
There is no single “best” machine.
Excellent SABR can be delivered using several modern technologies, including:
* Varian TrueBeam
* Varian Edge
* CyberKnife
* Halcyon
* Ethos
* MR-LINAC systems
* Other advanced linear accelerators
Each platform has particular advantages.
For most patients, the experience of the treating team, the quality of treatment planning and rigorous quality assurance are more important than the brand of machine.
Choosing an experienced centre that performs SABR regularly is often more important than choosing a particular technology.
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What questions should I ask before choosing where to have SABR?
Choosing where to have radiotherapy is an important decision. Useful questions include:
* Which imaging is used for treatment planning?
* How is tumour movement managed during treatment?
* What technology will be used and why?
* What are the expected benefits and risks for my situation?
* What are the alternatives to SABR?
* Will I receive follow-up imaging after treatment?
* What clinical trials might be appropriate for me?
Every patient’s situation is unique. A consultation can help you understand whether SABR is the most appropriate treatment and what outcomes are expected.
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CyberKnife® Frequently Asked Questions
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What is CyberKnife®?
CyberKnife® is an advanced robotic radiation therapy system that delivers stereotactic radiotherapy (SABR/SBRT) with exceptional precision. Despite its name, it is not surgery and there are no incisions, scalpels or anaesthetic involved.
CyberKnife uses a compact linear accelerator mounted on a robotic arm to deliver hundreds of precisely targeted radiation beams from many different angles. During treatment, sophisticated imaging continuously checks the tumour’s position and automatically adjusts for movement, helping maintain accuracy throughout the procedure.
CyberKnife can treat tumours almost anywhere in the body, including the brain, spine, lung, liver, pancreas, prostate and kidney.
For many patients, CyberKnife offers an effective non-invasive alternative to surgery, particularly when an operation would be difficult or carries significant risks.
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Is CyberKnife surgery?
No.
Although the name includes the word “knife,” CyberKnife is not an operation.
There are:
* No cuts or incisions
* No general anaesthetic
* No stitches
* No hospital admission for surgery
* No surgical recovery
Instead, highly focused radiation is delivered from outside the body while you lie comfortably on the treatment couch.
Most patients return home shortly after each treatment session.
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How does CyberKnife work?
CyberKnife combines several advanced technologies into one treatment system.
These include:
* Robotic radiation delivery
* Real-time X-ray imaging
* Computer-guided treatment planning
* Automatic tumour tracking
* Continuous correction for patient movement
During treatment, the system repeatedly checks the tumour’s position. If the tumour moves because of breathing or small body movements, the robotic arm automatically adjusts the radiation beam to maintain accuracy.
This allows high doses of radiation to be delivered while minimising exposure to nearby healthy tissues.
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What cancers can CyberKnife treat?
CyberKnife is used to treat a wide range of benign and malignant conditions.
Common indications include:
* Early-stage lung cancer
* Brain tumours
* Brain metastases
* Prostate cancer
* Liver tumours
* Kidney cancer
* Pancreatic cancer
* Spine tumours
* Adrenal tumours
* Recurrent cancers
* Selected head and neck cancers
* Oligometastatic disease
Not every patient requires CyberKnife. Your radiation oncologist will recommend the treatment approach that is most appropriate for your individual situation.
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Is CyberKnife only used for cancer?
No.
CyberKnife is also used to treat several non-cancerous conditions, including selected:
* Meningiomas
* Acoustic neuromas (vestibular schwannomas)
* Arteriovenous malformations (AVMs)
* Trigeminal neuralgia
* Benign spinal tumours
The suitability of CyberKnife depends on the condition being treated and the expertise available at your treatment centre.
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Does CyberKnife move with my breathing?
Yes.
One of CyberKnife’s unique features is its ability to track tumours that move during breathing.
For cancers in the lung, liver and upper abdomen, specialised imaging detects tumour movement and the robotic arm adjusts the radiation beam accordingly.
This allows treatment to remain highly accurate while reducing radiation exposure to surrounding healthy tissues.
Not every patient requires respiratory tracking, and different centres may use different motion management techniques depending on the cancer being treated.
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What happens during CyberKnife treatment?
Before treatment, imaging is performed to confirm the exact position of the tumour.
You then lie on the treatment couch while the robotic arm moves around you, delivering radiation from multiple angles.
The treatment is painless.
Unlike some other stereotactic systems, the robotic arm moves throughout treatment to optimise the delivery of radiation.
Treatment sessions typically last between 30 and 90 minutes, depending on the complexity of the plan.
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Does CyberKnife hurt?
No.
You cannot feel the radiation during treatment.
Some people experience fatigue or mild treatment-related side effects over the following days or weeks, depending on the area treated, but the treatment itself is painless.
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Is CyberKnife better than a LINAC?
Not necessarily.
Both CyberKnife and modern linear accelerators (LINACs) can deliver excellent stereotactic radiotherapy.
CyberKnife offers advantages for some situations, including:
* Continuous robotic tracking
* Treatment of moving tumours
* Highly flexible beam delivery
* Some complex anatomical locations
Modern LINAC systems also have important advantages, including:
* Faster treatment delivery
* Ability to treat a wider range of cancers
* Advanced cone beam CT imaging
* Surface-guided radiotherapy
* Adaptive treatment on selected systems
There is no single “best” machine. The most appropriate technology depends on your diagnosis and treatment goals.
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What is the difference between CyberKnife and Gamma Knife?
Although both treatments deliver stereotactic radiotherapy, they are designed for different purposes.
Gamma Knife is used exclusively for conditions within the brain and is considered one of the most accurate treatments available for many intracranial conditions.
CyberKnife treats both brain and body tumours, including cancers of the lung, prostate, liver, pancreas and spine.
Gamma Knife uses multiple cobalt radiation sources focused on a single target, while CyberKnife uses a robotic linear accelerator that delivers radiation from many different positions.
Both technologies achieve excellent outcomes when used for the appropriate indication.
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What questions should I ask before choosing CyberKnife?
Useful questions include:
* Is CyberKnife the best treatment for my cancer, or are there other options?
* Why have you recommended this treatment?
* How many CyberKnife patients does your team treat each year?
* What results have you seen for patients with my type of cancer?
* Will my case be discussed in a multidisciplinary meeting?
* How will tumour movement be managed during treatment?
* What side effects should I expect?
* What follow-up imaging will I need after treatment?
* Are there any clinical trials that might be appropriate for me?
An informed discussion with your radiation oncologist can help you understand the potential benefits, risks and alternatives so you can make the decision that is right for you.
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What is Gamma Knife®?
Gamma Knife® is a highly specialised form of stereotactic radiosurgery (SRS) used to treat conditions within the brain. Despite its name, Gamma Knife is not surgery—there are no incisions, no scalpel and no general anaesthetic.
Instead, Gamma Knife uses up to 192 finely focused beams of gamma radiation that converge precisely on a target within the brain. Each individual beam is too weak to damage healthy tissue significantly, but together they deliver a powerful dose of radiation to the tumour or abnormality.
Gamma Knife is one of the most accurate forms of radiation treatment available and has been used successfully to treat patients worldwide for more than 50 years.
It is commonly used for:
* Brain metastases
* Meningiomas
* Vestibular schwannomas (acoustic neuromas)
* Pituitary adenomas
* Arteriovenous malformations (AVMs)
* Trigeminal neuralgia
* Selected other benign and malignant brain tumours
For many patients, Gamma Knife provides an effective alternative to open brain surgery.
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Is Gamma Knife surgery?
No.
Although the treatment is called Gamma Knife radiosurgery, it is not an operation.
There are:
* No cuts or incisions
* No stitches
* No scalpels
* No removal of brain tissue
* Usually no overnight hospital stay
Instead, precisely focused radiation is delivered from outside the body while you remain awake throughout the procedure.
Most patients return home on the same day.
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How does Gamma Knife work?
Gamma Knife works by delivering hundreds of precisely focused beams of radiation to a carefully defined target within the brain.
The radiation damages the DNA of abnormal cells, preventing them from growing and dividing.
The effect depends on the condition being treated.
For example:
* Brain tumours gradually shrink or stop growing.
* Brain metastases are destroyed over weeks to months.
* AVMs slowly close off over several years.
* Trigeminal neuralgia is relieved by interrupting pain transmission within the trigeminal nerve.
Because the radiation is focused so precisely, surrounding healthy brain tissue receives only a small dose.
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What conditions can Gamma Knife treat?
Gamma Knife is used for a wide range of conditions affecting the brain.
Common indications include:
Brain metastases
Gamma Knife is widely used to treat one or more secondary cancers that have spread to the brain. It provides excellent local tumour control while avoiding many of the side effects associated with whole-brain radiotherapy.
Meningiomas
Many small or medium-sized meningiomas can be effectively controlled with Gamma Knife, particularly if surgery would be difficult or carries increased risk.
Vestibular schwannomas (acoustic neuromas)
Gamma Knife is commonly used to stop tumour growth while preserving hearing and facial nerve function whenever possible.
Pituitary adenomas
Selected pituitary tumours can be treated after surgery or when surgery is not appropriate.
Arteriovenous malformations (AVMs)
Gamma Knife causes the abnormal blood vessels to gradually close over several years, reducing the long-term risk of bleeding.
Trigeminal neuralgia
Gamma Knife can relieve severe facial pain when medications are ineffective or surgery is not suitable.
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What happens before Gamma Knife treatment?
Before treatment you will undergo several preparation steps.
These usually include:
* Consultation with your treating specialist
* MRI brain scan
* Sometimes CT imaging
* Review by the multidisciplinary team
* Detailed treatment planning using specialised software
Depending on the type of Gamma Knife system being used, either a lightweight stereotactic frame or a custom-made mask will be used to keep your head still during treatment.
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What happens during Gamma Knife treatment?
You lie on the treatment couch while your head is held securely using either the stereotactic frame or a custom mask.
The treatment machine then delivers radiation automatically according to the personalised treatment plan.
Depending on the size and number of targets, treatment usually takes between 20 minutes and several hours.
Once treatment is complete, most patients return home the same day.
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Does Gamma Knife hurt?
No.
You cannot feel the radiation during treatment.
If a stereotactic frame is used, local anaesthetic is given before the frame is attached to the scalp, so discomfort is usually minimal.
Mask-based treatments require no frame.
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Is Gamma Knife more accurate than other radiosurgery?
Gamma Knife is widely regarded as one of the most accurate forms of intracranial radiosurgery.
Its design allows radiation to be focused with sub-millimetre precision, making it particularly well suited to treating very small targets within the brain.
However, modern linear accelerator (LINAC)-based radiosurgery systems also achieve excellent accuracy and clinical outcomes.
The best treatment depends on the condition being treated, the available technology and the experience of the treating team.
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What is the difference between Gamma Knife and CyberKnife?
Both Gamma Knife and CyberKnife deliver stereotactic radiation, but they are designed for different purposes.
Gamma Knife
* Treats the brain only
* Uses multiple cobalt radiation sources
* Designed specifically for intracranial conditions
* Extremely high accuracy
* Often delivered in a single treatment
CyberKnife
* Treats both brain and body
* Uses a robotic linear accelerator
* Can track moving tumours
* Commonly used for lung, prostate, liver, pancreas and spine tumours as well as some brain conditions
Both systems provide excellent outcomes when used for the appropriate clinical indication.
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What questions should I ask before choosing Gamma Knife treatment?
Useful questions include:
* Is Gamma Knife the best treatment for my condition?
* Are surgery or observation reasonable alternatives?
* How many Gamma Knife procedures does your team perform each year?
* Will my case be discussed at a multidisciplinary meeting?
* What are the chances of controlling my condition?
* What side effects should I expect?
* Will I need steroids after treatment?
* How often will I need follow-up MRI scans?
* What symptoms should prompt me to seek urgent medical attention?
These questions can help you understand the potential benefits and risks of treatment and make an informed decision together with your specialist.