After individualized pre-operative teaching, the patient is admitted to the Upstate Gamma Knife Center on the morning of surgery. The patient is prepared for the first stage of the Gamma Knife procedure, which involves placing the patient's head in the Leksell Stereotactic Coordinate Frame. The patient may be lightly sedated, and local anesthetic is used on the spots where four small pins will secure the frame to the head. The wounds from these pins are tiny, heal quickly and leave minimal scars. The patient's head does not have to be shaved. The frame is secured throughout the treatment and immobilizes the patient's head inside the treatment machine. It also provides the reference for determining the treatment target.
With the head frame attached, the patient has an MRI or a CT scan to localize the lesion's shape and gather as much information as possible about the lesion and surrounding structures. These painless tests take about an hour. In certain instances, additional imaging studies such as angiograms or cisternograms may be needed and these will be discussed by the surgeon with the patients in advance.
The MRI and CT images are then fed into a dedicated computer system used to plot the trajectory and doses of the radiation. This stage of the treatment planning involves the entire Gamma Knife team, including Neurosurgeon or Otolaryngologist, Radiation Oncologist and Medical Physicist. Dose distribution generally takes less than one hour. This is the most labor-intensive phase of the Gamma Knife treatment, because the radiation trajectory must be tailored to the exact shape of the lesion.
At this stage, the patient is placed on the couch of the Gamma Knife unit, and the patient's head is secured to the treatment table for treatment delivery so that the target is at the exact point where the 192 beams of radiation will intersect. The physicians then leave the treatment room and administer the treatment from a control panel in an adjoining room. The patient is moved into the heavily shielded Gamma Knife unit for the painless radiation treatment, which usually lasts 20 to 40minutes. During the treatment, the patient is monitored by a video system and may communicate through a two-way intercom. The patient is able to relax, listen to music or even sleep.
After treatment, the frame is removed and patients are observed in the Gamma Knife Center for a short period of time. Most patients are then discharged home. Once discharged, the patient can return to regular activity within a few days. Follow-up visits with both the Neurosurgeon or Otolaryngologist and the Radiation Oncologist are scheduled to check the patient's neurological condition. These examinations generally occur at one to two months and six months, then regularly at three month to one-year intervals, depending on the patients' disease process and ongoing condition.