The Day of Your Treatment
Step 1: Attaching the head frame
Step 3: Planning your treatment
Step 4: Providing the treatment
You will be admitted to the hospital the day of the procedure. Before your procedure you'll be asked to sign a standard consent form, which will give us permission to treat you. The nurse will insert an IV line and give you premedication. The process of preparing for treatment consists of four steps:
Step 1: Attaching the head frame
We will take you to the patient preparation area to be fitted with the stereotactic head frame.
This frame serves two purposes: (1) It shows up on the MRI and other imaging procedures used to plan your treatment, and (2) it fits into the Gamma Knife unit's collimator helmet, which keeps your head stationary and precisely positioned during the treatment.
We will give you a local anesthetic (injected just under the skin) to numb the areas where the frame will be attached. The frame will be secured to your skull with screws that are fastened against the outer surface of the skull bone.
There is some discomfort involved in this part of the procedure, which takes about 10 minutes. (For young children, general anesthesia is usually administered before the process begins.)
Step 2: Taking precise images
When the head frame is in place, we will take images such as MRI or CT scans to pinpoint the location of the tumor or AVM. The imaging technologist will inject contrast through your IV line. For AVM treatments, angiography (DSA) will follow. After we take the images, we transfer them digitally to the planning workstation.
Step 3: Planning your treatment
You will rest while the Gamma Knife team of physicians uses the images and an advanced program to develop your treatment plan. This planning system enables the team to determine the amount and duration of radiation. The treatment planning phase may take up to several hours. You'll spend this time resting in your hospital room or in the waiting area in the Gamma Knife Center.
Step 4: Providing the treatment
Once your individualized treatment plan is completed and approved by the team, we will bring you to the room that contains the Gamma Knife. It houses the gamma radiation used in the treatment, the collimator helmet, and the couch. We will set the coordinate numbers on your head frame, which will be double-checked and fed into the Gamma Knife computer. After you lie down on the couch of the Gamma Knife, we will position your head in the appropriate collimator helmet.
This places the target at the exact intersection of the beams (focus). The Gamma Knife team will leave the room to conduct your treatment from the control panel in the next room.The couch is moved into position in the Gamma Knife's heavily shielded sphere.
The beams of radiation align on the targeted tissue inside the head and remain fixed on the target for the prescribed period of time.
Because the Gamma Knife procedure is minimally invasive, you should experience virtually no discomfort during the treatment.
The couch will move out of the unit for us to change the helmet or set new coordinate numbers.
Then the couch again moves into treatment position inside the unit. This will be repeated as many times and with as many different helmets as prescribed by your treatment plan.
If your treatment allows it, we will use an automatic positioning system (APS), which will run though all the focus points one by one. There are no loud noises during the treatment.
A video and two-way voice communications system will allow you to be in contact with the Gamma Knife team throughout your treatment. You may also listen to a radio program, or your own favorite tape or compact disk, if you like.
The total time you will be in the treatment position (when the target is exposed to radiation) usually ranges from 15 to 60 minutes but may be up to several hours, depending on the complexity of your treatment.
The total time you will spend in the Gamma Knife area may be two or three times longer, depending on the number of individual shots, settings of the coordinate numbers and changes of the collimator helmet in your treatment plan.
The couch will automatically move out of the unit when your treatment is finished. After your treatment, we will remove the head frame, apply a dressing, and you will return to your room.
There is no need for post-anesthesia recovery or intensive care unless the treatment was carried out under general anesthesia (children).You will probably be discharged from the hospital the following day, and most people return to their normal daily activities in a day or two.
