Stereotactic Radio Surgery

Overview of Stereotactic Radio Surgery in India

Stereotactic radiosurgery (SRS), or stereotactic radiation therapy (SRT), is an advanced form of radiation treatment that uses advanced techniques to provide precise radiation treatment using up to three-dimensional imaging and localisation techniques for delivering highly localised radiation to an area of interest (lesion) or an area of interest (tumor) within the body. Stereotactic radiosurgery is performed by delivering multiple beams of radiation from non-coplanar sources, which are all aimed at the same targeted area from different angles, but the whole area is not in the same position.

Bran metastasis is the most frequent malignancy located inside the cranial vault. According to research studies, approximately one in ten patients with cancer has been diagnosed with brain metastases as a result of complications related to their cancer treatment.

This advanced form of radiation therapy is conducted as a team effort among many specialists, including radiation oncologists, radiologists, medical physicists, therapists, nurses, and other expert medical professionals who work together as part of a comprehensive care team for the patient.

What is Stereotactic Radiosurgery (SRS)?

Stereotactic Radiosurgery (SRS), a non-invasive type of External Beam Radiation Therapy (EBRT), is used to deliver external beam radiation treatment in an accurate manner to various areas of the body (e.g., brain, neck, lung, liver, spine) in order to treat tumors or other abnormal tissue. Stereotactic radiosurgery is different from traditional surgery in that it does not require any cuts to the skin. 

Instead, it utilises sophisticated three-dimensional (3-D) imaging technology combined with a high level of precision to deliver multiple, highly concentrated beams of radiation directly to the tumor site. SRS techniques are often used by radiation oncologists and neurosurgeons to treat small malignant tumors (i.e., cancerous), but also benign tumors or other types of brain abnormalities, such as metastatic brain tumors, meningiomas, or chordomas.

In addition to accurately targeting the tumor site, stereotactic radiosurgery can help minimise damage to healthy tissue surrounding the tumor site and reduce the risk of infection compared to surgery. This makes SRS a safer option for patients who have had recent surgical procedures. The determination to utilise SRS will depend on each individual’s unique health status as well as the medical condition(s) being treated, and not solely on their chronological age.

Types of Stereotactic Radio Surgery:

 Three types of technology are used, basically, to deliver radiation during stereotactic radiosurgery.

Linear accelerator (LINAC) machines use X-rays—photons—to treat cancerous, as well as noncancerous, abnormalities in the brain and other regions of the body. LINAC machines are also called by the brand name of the manufacturer, such as CyberKnife, Axesse, Novalis Tx, TrueBeam and XKnife. These devices can carry out SRS in just one session, or they can do it across about three to five sessions for bigger tumors, which many people refer to as fractionated stereotactic radiotherapy.  

Gamma Knife machines use 192 or 201 small beams made of gamma rays, which are aimed precisely at the target to treat cancerous and noncancerous brain abnormalities. Gamma Knife machines are less common compared with LINAC machines, and they tend to be used mainly for small to medium tumors plus lesions in the brain linked with a range of conditions.

Proton beam, also known as charged particle radiosurgery, is the newest variety of stereotactic radiosurgery. As of now, it’s available only in a handful of centres worldwide. It can manage brain cancers in a single session with stereotactic radiosurgery, or it can use fractionated stereotactic radiotherapy to treat body tumors across multiple sessions.

Procedure:

With​‍​‌‍​‍‌​‍​‌‍​‍‌ SRS, it is your doctor who remotely operates the SRS machine by controlling a computer linked to the device. The patient stays in the room with the SRS machine while the doctor performs the work on the computer in a different room. The computer is equipped with imaging software, which is able to display the treatment area, thereby allowing the medical staff to properly position the patient. At times, the system may provide live photos of the tumor during the treatment. This is known as image-guided radiation therapy.

Your medical team will likely be doing the following during this time:

Go over with you what is going to happen. Part of this is showing you the intercom system. You will be able to talk with the medical team the whole time.

Assist you in getting on the treatment table and comfortably placing the immobilisation devices. For instance, you may be given a head frame or a mask to wear to make it harder for you to move during the treatment. The reason for this is that by locking your position, they can only irradiate the tumor and keep the healthy tissue safe.

Perform imaging tests. Diagnostic tools include MRI, CT, and (in some cases) angiography. Once the tumor's exact spot has been determined, your team can create treatment beams that specifically target the tumor.

Plan the therapy. Your healthcare professionals will establish whether you will be treated with a single high dose of radiation or with the smaller doses over the sessions. The lesser doses given to you over your treatment period are known as “fractionated treatment” or “stereotactic radiotherapy.”

Administer the therapy. Stereotactic radiosurgery is performed with the SRS machine. You will simply be in the room with the SRS unit while it emits the radiation. Stereotactic radiosurgery is not painful, and so you will not notice anything. However, you might be able to hear the moving sound of the ​‍​‌‍​‍‌​‍​‌‍​‍‌equipment.