Gamma Knife
Gamma Knife, also known as stereotactic radiosurgery (SRS) or stereotactic radiotherapy, is a noninvasive medical technology designed to treat brain tumors and other neurological issues using highly targeted gamma radiation. Developed by Swedish neurosurgeon Lars Leskell, it employs 201 focused beams of radiation that precisely target tumors while minimizing damage to surrounding healthy brain tissue. The procedure begins with the application of a local anesthetic and the attachment of a lightweight frame to the patient's head, which is essential for accurate targeting. Patients remain awake during the treatment, which can last from a few minutes to over an hour, depending on the tumor's characteristics.
Post-treatment, patients typically return home the same day and can resume normal activities within a couple of days. The risks associated with Gamma Knife surgery are low due to its non-invasive nature; however, some patients may experience mild side effects such as soreness, temporary swelling, or headaches. The full therapeutic effects of the treatment may take weeks to months to manifest. Overall, Gamma Knife represents a significant advancement in brain tumor treatment, providing an alternative to traditional open-brain surgery while offering favorable safety and recovery profiles.
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Subject Terms
Gamma Knife
ALSO KNOWN AS: Radiosurgery, stereotactic radiosurgery (SRS), stereotactic radiotherapy
DEFINITION: The Gamma Knife, not actually a knife, is a large precision system that delivers 201 intensely focused beams of gamma rays to treat tumors and other problems of the brain and nervous system. It resembles a computed tomography (CT) scanner. Gamma Knife technology was developed by Lars Leskell (1907–86), a Swedish neurosurgeon.
Cancers treated:Brain tumors, cancerous tumors that originate elsewhere in the body but have spread to the brain
Why performed: Gamma Knife “surgery” is a noninvasive alternative to traditional open-brain surgery. The precisely focused radiation beams of the Gamma Knife allow surgeons to treat very small, deep-seated tumors without damaging nearby brain tissue.
Patient preparation: Patients should not eat or drink anything after midnight the night before the procedure. They should inform their doctor if they are taking medication to control diabetes, are allergic to shellfish or iodine, or have implanted medical devices in the body. Patients must remove glasses, contact lenses, jewelry, makeup, nail polish, wigs, and dentures.
Steps of the procedure: Surgeons apply a local anesthetic and use four screws to attach a lightweight frame to the patient’s head. The frame prevents the head from moving and allows surgeons to identify the treatment target accurately. With the head frame in place, surgeons take magnetic resonance images of the brain to establish the exact size, shape, and location of the target. From the images, surgeons develop a specific treatment plan.
For the treatment, the patient lies on a couch. A helmet is attached to the head frame. The couch slides into the Gamma Knife unit, where radiation destroys the tumor. The patient is awake during the procedure, which lasts from a few minutes to more than an hour, depending on the size and location of the tumor.
After the procedure: When the treatment is completed, the head frame is removed. In most cases, the patient goes home the same day and returns to a normal routine in a day or two.
Risks: Because surgeons make no incisions, the risk of complications from the use of the Gamma Knife is low. Some patients feel minor soreness from the head frame. Temporary swelling and irritation are also possible. Some patients experience mild headache, dizziness, or nausea, which last only a short while.
The dose of radiation outside the target is very low and poses little risk. Occasionally, patients experience swelling in the brain, which is temporary and treatable.
Results: The effects of radiation treatments take time: weeks, months, or even years.
Bibliography
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