Gamma Knife details

My wife Joanie tells me that several people have requested more info about the Gamma Knife – what it is, why I needed it, and what it was like for me during and after the procedure.

Gamma Knife is a non-invasive radiosurgery procedure that kills targeted tissue in the brain. Despite its name, it does not involve a real knife. It works by aiming up to 201 low-level radiation beams from many angles such that they all intersect on the unwanted tissue. Therefore, good brain tissue gets exposed to very low levels of radiation but the targeted tissue gets hit with the sum of all those low levels, destroying that tissue.

Here is a description of the procedure from https://gammaknife.com: “On the day of treatment, the patient may be given light sedation. Next, local anesthesia is used to secure a head frame to the patient’s head…With the frame in place, the patient undergoes an MRI or CT scan…in order to locate the lesion in the brain to be treated. Using the imaging procedure, the treating team can define the position of the lesion(s) inside the patient’s head. While the patient rests, the treatment team (which typically consists of a neurosurgeon, radiation oncologist and physicist) creates a treatment plan. This takes from 30 to 90 minutes to complete, depending upon the geometry and location of the target(s). When the individual treatment plan is completed, the patient lies on the Gamma Knife couch so that their head is precisely positioned for treatment. The patient is then moved automatically into the machine and treatment begins. Treatment typically lasts from 20 minutes to 2 hours, during which time the patient feels and hears nothing. At the completion of the treatment, the patient is automatically moved out of the machine and the head frame is removed. The patient usually goes home at this point but may remain in the hospital overnight for observation on occasion.”

In my case, there was only one metastatic lesion to be treated and the time from walking into the hospital to being wheelchaired out to our car was about five hours.

After changing into a stylish hospital gown, I was given an Ativan pill for anxiety even though I wasn’t aware of experiencing any anxiety.

Then the neurosurgeon and an RN attached the head frame. The purpose of the head frame was to ensure that the radiation beams could be directed with precision to the brain lesion, and to prevent my head from moving during imaging and treatment procedures. Despite the pictures in my previous blog entry, those 15 minutes or so of having the frame attached weren’t bad. The frame is precisely positioned and secured with four pins, which sounds torturous but the combination of Ativan and many injections of local anesthetic made it just slightly unpleasant.

After the head frame was secured to my head, I was placed in an MRI machine. The head frame was attached to something on the MRI machine, ear plugs were placed in my ears, and the very loud MRI was done.

After the MRI, I was allowed to relax while the neurosurgeon, a physicist, and perhaps others used data from the MRI to develop my Gamma Knife plan.

Then, with the head frame still very securely attached to my head, I was placed in the Gamma Knife machine. The head frame was attached to something on the Gamma Knife machine and then the Gamma Knife procedure began. I’m guessing that procedure took about 20 minutes. Unlike an MRI, it was very quiet. They had asked what kind of music I wanted to listen to and granted my wish for light classical.

When the Gamma Knife procedure was finished they removed the head frame, gave me time to change back into my clothes, fed me a pretty good breakfast of scrambled eggs, a sausage patty, and biscuits and gravy, and wheelchaired me to our car that was waiting for us complements of the free valet service.

It’s been four days now since that procedure. My eyelids were badly swollen for the first couple of days, affecting my vision. My thinking was pretty fuzzy also. Two of the four places where pins were secured to my head are still a bit sore. But all of that is getting better and I expect to be free of those issues sometime next week.