Radiosurgery, often termed stereotactic radiosurgery (SRS), is a medical procedure that uses highly focused radiation to treat diseases, primarily tumors, throughout the body. Despite its name, it does not involve surgical incisions or cutting. Instead, it precisely delivers intense doses of radiation to a specific target area. This non-invasive approach aims to achieve results similar to traditional surgery by destroying or inactivating diseased cells.
Core Principles and Precision
Radiosurgery operates by converging numerous precisely aimed radiation beams onto a defined target. Individually, each beam passes through healthy tissue with minimal effect, but where they intersect, they deliver a potent, therapeutic dose of radiation. This concentrated energy damages the DNA within the targeted cells, hindering their ability to reproduce and grow, which leads to the shrinking of tumors or the closing of abnormal blood vessels over time. The precision of this technique helps minimize radiation exposure to surrounding healthy tissues.
Achieving this high level of precision relies on advanced three-dimensional imaging techniques, such as computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET). These images help medical teams accurately pinpoint the exact location, size, and shape of the target within the body. Patient immobilization techniques are also crucial to ensure the target remains stationary during treatment, preventing movement that could compromise accuracy. These methods can include rigid head frames for brain treatments or custom-fitted masks and body molds for other areas of the body.
Unlike conventional radiation therapy, which typically delivers smaller doses over many weeks to allow healthy cells to recover, radiosurgery delivers a much higher dose per session in a single treatment or a few sessions, usually between one and five. This condensed treatment schedule is possible due to the extreme accuracy of the radiation delivery. Common radiosurgery systems include the Gamma Knife, which uses gamma rays primarily for brain and head conditions, and linear accelerator (LINAC) machines, such as CyberKnife and TrueBeam, which use X-rays for both brain and body targets. Proton beam therapy is another system that uses protons, allowing for even more controlled dose delivery.
Conditions it Addresses
Radiosurgery is a treatment option for a range of medical conditions, particularly those located in areas difficult to access with traditional surgery or for patients who may not be suitable surgical candidates. It is commonly used for various types of brain tumors, including benign and malignant growths, and those that have spread to the brain from other parts of the body. For instance, it can effectively treat small or hard-to-reach tumors due to its highly focused beams.
This technique also treats arteriovenous malformations (AVMs), which are abnormal tangles of blood vessels that can disrupt normal blood flow. Another condition addressed is trigeminal neuralgia, a neurological disorder characterized by severe facial pain.
Beyond the brain, radiosurgery, often referred to as stereotactic body radiation therapy (SBRT), is increasingly applied to localized cancers in the lung, liver, spine, and prostate. It is often considered for patients with lung tumors who cannot undergo surgery due to other health conditions. For prostate cancer, SBRT offers a condensed treatment schedule, often completed in five sessions or less. For spinal tumors, it delivers high doses of radiation while limiting exposure to the spinal cord.
The Patient Journey
Undergoing radiosurgery begins with a consultation where a multidisciplinary team evaluates the patient’s condition and determines the treatment plan. Detailed imaging studies, such as MRI, CT, or angiograms, are then performed to map the target area.
During the planning phase, an immobilization device is custom-fitted to the patient to ensure stability throughout the procedure. For conditions in the brain, this might involve a specialized head frame secured to the skull with local anesthetic, or a non-invasive mask. For body treatments, molds or vacuum-assisted bags help maintain precise positioning.
The radiosurgery procedure is usually performed on an outpatient basis. The treatment is generally painless, and patients remain awake and can communicate with the medical team throughout. The duration of the procedure can range from a few minutes to several hours, depending on the complexity and size of the target. After the procedure, many patients can return to their daily activities relatively quickly. Some temporary side effects, such as fatigue or mild skin irritation, may occur in the initial weeks.