Stereotactic Radiation Therapy

Stereotactic radiation therapy (SRT) is also referred to as stereotactic body radiation therapy (SBRT) or stereotactic ablative radiation therapy (SABR). It is an advanced technique used to treat small, well defined tumours or high risk postoperative areas. It can be used to treat both primary and metastatic (sometimes referred to as secondary tumours – these are tumours that have spread from other organs in the body) cancers in the brain, spine, bones, liver and lung. Stereotactic radiation therapy can deliver large ablative doses with good results in lung and brain cancers and metastatic tumours in the body and bones. It is non-invasive with no general anaesthetic risk and is suitable for patients who are eligible but unfit for surgery.

The technology allows a high dose of radiation to be delivered to the tumour very precisely, without compromising surrounding healthy organs due to the ability to treat with sub millimetre accuracy. Due to the larger daily doses of radiation delivered to patients with stereotactic radiation therapy, treatments can be completed within a single treatment, or multiple treatments spanning over 2-10 days. Each daily treatment usually takes no longer than 20 minutes. Images will taken before treatment commences to ensure that the patients are in the right positions before the radiation is started. This ensures accuracy and precision of treatments from day to day.

Stereotactic radiation therapy is most commonly used to treat secondary tumours in the brain. Stereotactic radiation therapy is also used to treat some benign (non-cancerous) tumours such as meningiomas, pituitary adenomas and acoustic neuromas as well as some blood vessel conditions such as arteriovenous malformations.

Stereotactic radiation therapy for the brain will involve the making of a customised mask that will be used during treatment to ensure the patient’s head does not move during treatment allowing the machine to precisely target the tumour.

Compared to traditional radiation therapy for metastatic disease to the brain which involves treating the entire brain, stereotactic radiation therapy only targets the individual metastatic tumours with high doses. This provides less radiation to healthy brain tissue, reduces the chance of adverse intellectual function, reduces the impact of side effects (e.g. hair loss and headaches) providing improved quality of life for patients.

There are state-of-the-art technologies which can deliver treatment to multiple brain tumours at one time. This reduces the need to treat multiple tumours separately, resulting in a much shorter treatment time for patients. Listed below are two examples of software used to help deliver this treatment. Other technologies may be used to treat multiple tumours, depending on the location of your treatment centre, but the software all work to achieve the best possible outcomes for patients.

Varian HyperArc

HyperArc is the latest technological advancement from Varian Medical Systems. It provides an end-to-end solution for multiple intra-cranial targets. The software seamlessly connects with the Varian TrueBeam linear accelerator (the machine that delivers radiation therapy) and allows for automated planning and the ability to accurately target multiple tumours while ensuring limited doses of radiation to surrounding healthy brain tissue.

Unlike some systems that require multiple setup points, HyperArc is able to deliver treatment to all targeted brain tumours using the one setup point. This means less setup on the bed for the patient and quicker treatment times.

BrainLab Elements

BrainLab Elements is an automatic brain metastases planning system. It brings together planning solutions to benefit clinicians and patients. It optimises and streamlines the planning processes based on each individual case allowing for high quality treatment plans for patients. It allows your care team to create the best possible plan to target tumours with precise accuracy.

Stereotactic radiation therapy to the lung is most commonly used to treat early stage primary lung cancer or metastatic tumours that have spread from other organs in the body. There are good early results for stereotactic radiation therapy to the lung compared to surgery. This treatment is especially suitable for elderly patients who may have reasons for not being fit or unwilling to undergo surgery.

Stereotactic radiation therapy for lung cancer involves the use of specialised equipment to ensure the accurate representation of your breathing motion. During your simulation or CT appointment, the radiation therapists will monitor and record your breathing pattern so that we can replicate it each day for treatment. By knowing exactly where the tumour moves during your breathing cycles, we can reduce the amount of healthy lung being irradiated by focusing and targeting the treatment beams precisely at the moving tumour.

Stereotactic radiation therapy to the liver is most commonly used to treat primary liver tumours. However, it can also be used to treat secondary cancers in the liver where suitable. This is typically available at our sites that are affiliated or attached to a hospital campus, due to additional support these patients require during treatment.

Stereotactic radiation therapy for liver cancer involves the use of specialised equipment to ensure the accurate delivery of treatment. Your oncologist will organise for some markers to be implanted into your liver prior to treatment. This allows us to monitor the exact position of the tumour during treatment, ensuring the tumours are precisely identified and targeted, allowing the surrounding healthy liver to have minimal exposure to radiation during treatment.

Using our auto beam hold technology, if the machine detects that the markers move outside of the treatment beam, the beam will automatically switch off. The treatment will only proceed when the tumour is within the treatment beam.

Stereotactic radiation therapy to the spine is used to treat metastatic tumours that have spread from other organs in the body to the vertebrae. Your oncologist will use both your MRI scan and planning CT scan to a very high level of accuracy.

Given the proximity of the vertebrae bodies to the spinal cord, we use highly specialised immobilisation devices – ensuring patients remain in the exact same position, state-of-the-art delivery techniques and pre-treatment CT scans to ensure that treatment every day is pinpoint accurate.

Stereotactic radiation therapy can be used to treat tumours that have spread to bones within the body. Depending on which bone we are looking to treat, your oncologist and radiation therapists will develop and customise a treatment technique that is personalised to your needs.

Stereotactic radiation therapy can be used to treat oligometastatic disease which are secondary tumours that have spread beyond the original tumour and form within various organs.

Oligometastatic means “a few metastasis” and is generally the early systemic spread of cancer. If treated early, stereotactic radiation therapy for oligometastatic disease has been proven in large trials to extend the lifespan of patients and improve quality of life.

Oligometastatic disease may be treated with stereotactic radiation therapy with the aim of improving patient outcomes and controlling the disease.

Treatment technology, coupled with advanced imaging techniques, like a PET/CT scan, can be a powerful tool to clearly identify and accurately target these small tumours that might otherwise go undetected. Our radiation oncologists will be able to advise you if this treatment option is available and recommended for you.