What is Stereotatic Radiosurgery?
Stereotatic Radiosurgery (SRS) is a highly targeted and focused radiation treatment which delivers extremely high doses of radiation directly to the target to destroy it.
The term stereotactic is a term used in Neurosurgery to refer to the ability to accurately identify a point in 3-dimensional space. Radiosurgery uses technology used in neurosurgery to destroy the tumour. For more technical details, please see here.
Modern Linear Accelerator with 6 degrees of freedom robotic couch
Today, Frameless Radiosurgery is possible with modern navigational techniques such that patients no longer need to have a metal frame screwed into their skull for accurate targeting
Modern digital navigation achieves sub-mm accuracy
Understanding the difference between Surgery and Radiosurgery
Surgery involves physically cutting through tissue and bone to reach the tumor so as to remove it from the body.
Radiosurgery does not involve any cutting at all. The name was given because after destroying the tumor with high doses of focused radiation, the body automatically removes the dead cells, and the cure rate is as if surgery was done
Breast Cancer Brain Metastasis
- before SRS
Complete response 3 months after SRS
Spine Metastasis strangulating the spinal cord and compressing the surrounding thecal sac.
6 months after SRS, tumor has shrunk and the the spinal cord is no longer compressed. Patient no longer has pain and weakness
It is completely painless, bloodless and is done as an outpatient procedure.
Patient does not need to undergo open surgery and does not suffer from operation risks
Why should I choose Radiosurgery?The main reason patients choose Frameless Radiosurgery is because of its effectiveness and because it is non-invasive and painless. It is also very safe with a low side effect profile. Today, there is no need for a metal frame to be screwed into the patient’s skull, and treatment can be completed as fast as within 15min. In addition, in cancer patients, frameless Radiosurgery results in very low downtime, so this allows for patients to receive their chemotherapy cycles on time, so that the other areas of disease in the body can still continue to be kept under control while Radiosurgery addresses the target tumor.
What are the conditions treated using Radiosurgery?The most common type of cancerous tumour treated with Radiosurgery is Brain and Spine metastasis. This describes the situation when cells have spread from the original location either into the brain or to the spine. Studies have shown that using targeted radiation helps to preserve the memory of patients, which may be affected if the whole brain is irradiated. At the same time, hair loss can be avoided too. Many patients with brain or spine metastasis require other treatments such as chemotherapy, or they also may not be optimally fit for open surgery due to their situation. Hence, a non-invasive, low downtime option that is equally effective is preferred for these group of patients as compared to undergoing a major operation. Radiosurgery is also extremely effective for benign brain tumors such as acoustic neuromas (vestibular schwanommas), meningiomas and pituitary tumors with up to 90% cure rates achievable. Because of its effectiveness and very Low rates of side effects, Radiosurgery has replaced open surgery as the treatment of choice for uncomplicated benign brain tumors which require treatment. Patients are spared from major surgery and the risk of nerve damage.
What are other alternative treatment options?Other mainstream alternatives include Open Surgery, Minimally-Invasive surgery, and Thermal or Cryo-Ablations. It is important that treatments are tailored to the individual patient in a multi-disciplinary setting for the best outcomes. As mentioned above, SRS can be given in combination with other local treatments depending on the shape and location of the tumor.
What are the key areas I need to focus on when choosing my Radiosurgery treatment?Radiosurgery involves delivering extremely high doses of radiation to a focused area. Thus the margin for error is very small and radiation once released cannot be reversed. Hence not only must the Radiosurgeon in-charge be well trained in radiation medicine, he must also have the necessary training in handling the navigational software and radiation delivery equipment, as well as have sufficient clinical experience in giving high radiation doses to different areas of the body. In addition, he needs to ensure that his entire radiation team is well coordinated and familiar with Radiosurgery treatment protocols and quality assurance procedures so that the final result is safe and effective. As the saying goes, we are only as strong as our weakest link.
What is the difference between Gamma-Knife and Radiosurgery?Gamma-knife is the brand of one of the early machines used to deliver Radiosurgery. Because the navigational technologies were not as advanced in the past, patients required a Metal Frame to be screwed into their skull at 4 points so as to determine the location of the brain tumour. Today, this is no longer required, and patients are able to undergo ‘Frameless’ Stereotactic Radiosurgery which is able to achieve the same or better results in some cases than using older techniques. The most convenient method of delivering Frameless Stereotactic Radiosurgery is by using an Advanced Linear Accelerator with a 6-dimensions of freedom robotic couch. In gamma-knife, a Frame has to be screwed into the skull, followed by a planning MRI scan while the Frame is in place. After that, the patient waits with the frame on, while radiation planning is done. The treatment time can range from an hour to a few hours depending on the age of the radiation source. This results in the patient spending at least half or the entire day in the hospital for the treatment, with the Frame attached most of the day. Unlike Gamma-knife, patients who undergo Frameless SRS only need to do a planning CT scans (about 30min) a few days before the treatment date and then return after the plan is ready to receive the treatment which is delivered over 15-45 minutes. The reason for the difference lies in speed of the electrical source of the radiation beam and the versatility of the Linear Accelerator machine.
What is the difference between Radiotherapy and Radiosurgery?Radiosurgery packs all the dose usually given over 5-6 weeks, and gives it over 1-5 days. The Radiosurgeon is a Radiation Oncologist who is trained in both radiotherapy, oncology, and the complex technologies used to deliver Radiosurgery. Since radiation is the ‘knife’ which ‘cuts’ the tumor, it is critical that the Radiosurgeon is well versed with radiation medicine.
What is the difference between Proton Beam Therapy and Radiosurgery?Radiosurgery and Proton Beam Therapy are both precision radiation therapies. Radiosurgery avoids treating normal tissue by sophisticated beam shaping and modulation, while Proton Beam avoids treating normal tissue by reducing dose deposition during the exit of the beam. They can be used in combination, depending on the location of the target and the diagnosis of the patient. For more information on Proton Beam Therapy, click here.
Our Brain & Spine Radiosurgery Specialist
Dr Daniel Tan Yat Harn
Director & Senior Consultant Radiation Oncologist (Clinical Oncologist)
MBBS (SIN), FRCR (Clinical Oncology, UK)
FAMS (Radiation Oncology)
MBA (Healthcare Management)
Stereotactic Radiosurgery (SRS/SBRT)
Brain and Spine, Breast and Prostate Cancers
View Dr Daniel Tan's full profile here
Radiosurgery Articles & Publications by Dr Daniel Tan:
Source: Singapore Medical Journal, 2018
Source: International Journal of Radiation Oncology, 2017
Technical know-how in stereotactic ablative radiotherapy
Source : Journal of Medical Radiation Sciences, published 03 March 2016
Frameless Stereotactic Radiosurgery
Source : Medical Grapevine, August 2015
Source: The Straits Times, September 2015
Source: International Journal of Radiation Oncology, 2014
Source: Sage Journal, 26 April 2013
View more Articles & Publications by Dr Daniel Tan here.
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