Gamma Knife Radiosurgery
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The Day of Your Treatment

You should arrange for transportation on the day of treatment, as you should not drive yourself home after the procedure. Wear loose comfortable clothing that does not have any metal (earrings, belts, bracelets, buckles, zippers, snaps). Do not bring any valuables (jewelry, earrings, watch, money) to the hospital.

Please bring any medications you need to take for the day with you to ensure you do not miss any doses.

On the day of your surgery, you will report to the Admitting Department at Health Sciences Centre, usually between 5:30 and 5:45 am (820 Sherbrook entrance). Then you will proceed to the Gamma Knife suite (room GH 186B). You will remain in your own clothes. Your blood pressure and pulse will be monitored, and an intravenous will be started. Physicians will apply a stereotactic headframe. For this procedure, the skin and scalp will receive local anesthetic, or freezing at two points over forehead and two at the back of your head. The headframe is then secured tightly and you will feel pressure around your head. This discomfort is temporary, and once in place, the headframe is generally not painful. If required, sedation and analgesics (pain medication) are available. The application of the head frame is essential for accurate targeting of your specific lesion and keeping your head still during the GKS. This will be removed after the gamma knife treatment is completed.

After the frame is placed, you are assisted to the MRI department where you will have an MRI. To obtain a three dimensional localization of the target to be treated. This is performed with diagnostic imaging techniques such as MRI, CT Scan or angiography. The localizer box is placed upon the stereotactic head frame, and this shows external markers (fiducial) that identify the position of the brain and target with respects to the stereotactic head frame. The diagnostic imaging data is then transferred to the Gamma Knife surgery planning station. This procedure takes 20-30 minutes and is a crucial component of radiosurgery. Your treatment target will be localized in relation to the headframe, providing the stereotactic coordinates needed to plan your treatment. The MRI images are relayed back to the Gamma Knife suite immediately by computer so that the planning of your specific treatment can begin. Another necessary step in planning the GKS procedure is making simple measurements of your head. A plastic helmet is placed over the headframe and measurements are taken to establish the distance between the helmet and your head. This information will also be entered into the planning computer. The planning process may take several hours. The neurosurgeon, radiation oncologist and medical physicist will determine an optimal plan to treat your condition. During this time, your family members or friends can sit with you while you wait. Due to space constraints, only two companions are allowed.

At the planning station, the prescribed target and normal surrounding brain structures are identified, and the exact configuration and dose of focused radiation are determined. Several special steps are required to ensure precise identification of the target and optimal treatment plan, as determined by the trained neurosurgeon, radiation oncologist, and medical physicist.

The treatment plan is then transferred to the computer treatment console, which directly controls the operations of the Gamma Knife itself. The patient is brought into the Gamma Knife treatment room, still wearing their stereotactic head frame. They are positioned on the couch and the head frame docked to a hemisphere shaped collimator helmet. Several checks are performed to be sure that the treatment target is exactly positioned at the center of the collimator helmet.

Total exposure to the patient with respect to radiation is minimal (get examples) (make comment regarding pregnancy) Following Gamma Knife surgery, the stereotactic head frame is removed, and the patient is observed for a minimum of 30 minutes prior to discharge. Most patients go home thereafter, although under some circumstances admission into hospital over night may be recommended.

The Gamma Knife procedure itself is painless.
Once the plan is established, you will be taken into the gamma knife suite. Inside the treatment room, you will lie down on the couch. Your headframe will be docked with the automatic positioning system. This will keep your head still during your treatment.

Once you are safely positioned, you are ready for your treatment. At this point, the staff will leave the room, but you will be able to speak with the GK team by a two-way intercom and will be monitored with video monitors. You may speak to the staff at any point during your procedure. The actual treatment is silent and pain-free. The physicians will discuss the length of your treatment with you. The machine will automatically adjust your head position during the treatment, depending on the type of lesion you are having treated. To do this, the bed comes part way out of the machine and goes back in. If you are having a longer procedure, you are encouraged to bring in a CD or listen to our music during treatment to help you relax.

When the process is completed, the "bed" will automatically slide out of the machine and staff will re-enter the room to assist you in getting off of the table. You will return to the observation area and the headframe will be removed. This process may cause slight discomfort for a few moments. You may have slight bleeding from the pin sites, but this will heal over in a few days. Your intravenous will be taken out and your vital signs will be monitored. You will be observed by staff, and once you are stable you will be discharged home. You should arrange for transportation home, as you may be slightly drowsy from any medications you may receive and not safe to drive yourself home.

The gamma knife nurse will review teaching with you and you will be given a contact number for any questions or concerns that arise once you get home. You will receive a follow-up phone call from the nurse the next day and will be seen in the neurosurgery clinic in 8-12 weeks, depending on your condition. Follow-up MRI's will be discussed on discharge. You can have this done and have follow-up in your home city if you are coming to see us from out-of-town.

Special Note:

  1. All women of childbearing age will have a pregnancy test. Pregnancy is considered a contra-indication to Gamma Knife, especially in the first trimester.

  2. If you are being treated for an AVM, you will have an angiogram in addition to an MRI, which will make your stay a little longer, but you will still go home the same day.

For any inquiries about the Gamma Knife in Winnipeg, please call the Gamma Knife Patient Care Coordinator at (204) 787-7278, or e-mail

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