Gamma Knife is the only non-invasive radiosurgery system specifically engineered to treat delicate brain tissue. The basis of Gamma Knife surgery is to determine the diseased area in the head by computer based on stereotactic principles and to irradiate this area with gamma-rays derived from 192 Cobalt sources. While low-power rays from each source don’t harm the brain, high level of radiation effect is detected in areas where 192 rays are focused. Treatment without bleeding and surgical intervention is offered to patients. This treatment rules out the necessity of ICU and lasts only a couple of hours. Patients can get back to their daily lives after treatment.
Stereotactic radiosurgery damages DNA of the tumor or diseased tissue cells. As divisive and nutritional functions of irradiated tumor cells are ruined, tumor growth is blocked. Mostly upon treatment, targeted tumors are gradually reduced in size. Tumor reduction speed is approximately equal to growth speed. In treatment of vein glomus, which is also known briefly as AVM, Gamma Knife causes thickening of unusually wider veins and gradually blocks them. The blockage process of vein glomus spans over approximately 3 years.
Since malign tumors and metastases display rapid onset, they respond to treatment in a couple months at the same speed.
Factors considered in evaluating a patient for Gamma Knife treatment include a patient's age and general medical condition, location and size of the brain abnormality and previous treatments. If it is decided that Gamma Knife is not the best treatment option, other treatments will be discussed.
Radiation exposure to other parts of the body is extremely low, making it an excellent option for children and women of childbearing age.
Patients who are candidates for Gamma Knife are reviewed at weekly Gamma Knife meetings. Each patient's condition is evaluated by a team including neurosurgeons, radiation oncologists, physicists, neuro-radiologists, neuro-oncologists, nurses and radiation therapists.
Since 1968 Gamma Knife has been used for treatment of several diseases. According to 2017 data, over 1 million patients diagnosed with various brain diseases have been treated with Gamma Knife.
Diseases Treatable with Gamma Knife;
In addition to the diseases listed above, Gamma Knife treatment can be used for brain tumors in deeper locations and for patients who are not eligible for general anesthesia, cannot tolerate surgical intervention and do not accept open surgery. However, please note that the decision regarding use of Gamma Knife rests with your physician.
Prior to a Gamma Knife procedure, patients visit the hospital for possible blood tests, and to meet with the doctors who will participate in the procedure. Depending on your condition, your doctors may include a radiation oncologist or neurosurgeon. During your pre-procedure consultation, your doctor will record your medical history, perform a physical examination and provide time for you to ask questions.
The technique that allows the Gamma Knife to precisely target areas within the brain is called stereotaxy. Stereotactic radiosurgery is performed with the aid of imaging techniques called computerized tomography (CT) scanning, magnetic resonance imaging (MRI) and angiography. These are used together with special computer-assisted instruments to provide 3-D views of the target and surrounding brain structures. By studying these images, your doctor can accurately locate the abnormality within the brain, then precisely focus the gamma radiation beams on the abnormality.
The neurosurgeon will use local anesthesia to numb four spots on your scalp and forehead before attaching a "stereotactic frame." This frame allows highly precise treatment.
The treatment time will depend on your diagnosis. While the treatment is administered, you will lie on a treatment table. Your head will be held still during the session while 192 small radiation beams are focused simultaneously at the target. The size of the focal spot can be adjusted, and multiple focal spots can be combined together to deliver a high radiation dose precisely to one target or to multiple targets of almost any shape, anywhere in the brain.
During treatment, there's no pain. After treatment, the head frame is removed, and small adhesive bandages are applied where the stereotactic frame was secured.
You may be discharged shortly after the procedure. Some patients experience a mild headache, which can be treated with medication. Discharge and follow-up instructions will be explained, and you'll receive an instructional handout.
We will call you the following day to check on your status and answer any questions you may have.
The process of Gamma Knife treatment for children is similar to the process for adults, but special care is provided for pediatric patients including imaging studies before treatment, anesthesia tailored for children, recovery and subsequent treatment, if required.
The first step is to place the stereotactic frame. This procedure is done under local anesthesia, but sedation is preferred for younger children. If necessary, a mask is used instead of a frame. The mask is tailor-made for individual patients.
After that, neuro-radiological scanning is done. Depending on type of disease, MR, Tomography or angiography is performed. MRI is performed for every patient before treatment. Angiography is performed for patients with AVM.
Dosage suitable for the target mass is planned using special software. During this procedure the patients rest in their rooms.
Gamma Knife treatment begins immediately after the planning process. Upon completion of treatment, which takes only a short while, the patient is discharged on the same day and returns home.