Frameless Stereotactic Radiosurgery for Brain & Spine Tumors

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.

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.

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.

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.

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.

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.

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.