How Gamma Knife Works- Treatment and Follow Up


The Gamma Knife Perfexion works by utilizing the latest advanced diagnostic imaging and three-dimensional treatment planning software to deliver 192 finely-focused beams of gamma radiation to small targets inside the brain. The beams converge at a point to treat the affected tissue, while minimizing the damage of healthy brain tissue.


What happens during Gamma Knife treatment?

Once a patient’s condition is reviewed by our multidisciplinary team and Gamma Knife treatment is deemed appropriate, the patient will be scheduled for a treatment day. On the day of treatment, there are several steps that take place. Gamma Knife Perfexion treatment consists of the following steps:

1. PLACEMENT OF THE HEAD FRAME:  A stereotactic frame will be placed on the patient’s head and remain there throughout treatment. The frame is needed as a reference point during treatment planning, and it is used to hold the head in the exact position required for precise treatment.  This frame provides the Gamma Knife with an unmatched level of accuracy to perform the treatment procedure.


2. OBTAINING PRECISE IMAGES:   MRI, CT scans or angiography (a way to visualize the blood vessels) will be used to obtain images that clearly define where the tumor, AVM or treatment site is located.  These images are used to design a custom treatment plan for each patient.


3. TREATMENT PLANNING:   Once the images are transferred to the Gamma Knife's computer planning system, the team will examine them and accurately define the target. The detailed treatment plan they create will determine how long treatment will take. Planning a typical Gamma Knife treatment usually takes about an one hour.


4. TREATMENT:   Once the treatment plan has been carefully checked by the team for precision and safety and has been explained to the patient, treatment will begin. The patient will enter the Gamma Knife suite and recline on the couch portion of the Gamma Knife. The team will position the patient’s head in the machine. The team conducts treatment in an adjacent room, maintaining contact with the patient through video and intercom. Patients may choose to listen to the radio or music of their choice. When the treatment is over, the patient is taken out of the machine and the head frame is removed.  Most patients will be observed for a period of time and then released.  However, some patient may be required to stay overnight in the hospital.  Most individuals return to normal pre-treatment activities within a day or two.


5. POST GAMMA KNIFE TREATMENT:    The effects of Gamma Knife radiosurgery occur over several weeks to several years, depending on the type of medical condition treated. The radiation alters the DNA of the tumor or lesion being treated so that the cells no longer reproduce, eventually rendering the lesion static. Some abnormalities dissolve gradually, eventually disappearing. Others simply exhibit no further growth. The effectiveness of the treatment is monitored by appropriate imaging scans at regular intervals. A physician will monitor the patient’s treatment results by taking periodic MRI, CT scans or angiography. The Gamma Knife Center staff will stay in contact with the patient’s physician in order to monitor the treatment progress. We are available to provide further consultation on a patient case as needed.


For more information on what to expect, see the Frequently Asked Questions page.