Gamma Knife: How it Works
Utilizing the latest diagnostic imaging and specialized three-dimensional treatment planning software, the Gamma Knife doctors at UAMS design a customized treatment plan to direct radiation beams to converge on the target location, delivering the full treatment dose.As a noninvasive treatment option, the Gamma Knife Perfexion uses up to 192 different beams of radiation to treat a variety of brain abnormalities with extreme accuracy. Individually, each radiation beam is weak and passes harmlessly through healthy tissue.
Treatment Day: What Happens During a Gamma Knife Procedure
- Placement of the Stereotactic Head Frame: Using an oral and local anesthetic, the neurosurgeon will attached a lightweight head frame to the patient’s head using four small pins, about the size of the tip of writing pen or pencil. Some patients may also receive a light sedative. Patients have reported feeling pressure as the frame is attached but no pain. This head frame is very important as it is used as a guiding device during imaging and treatment planning to help accurately locate the targeted treatment area and as a rigid immobilization device to keep patients from moving during treatment. The head frame provides an unmatched level of accuracy not seen in “frameless” radiosurgery units.
- Imaging: After the placement of the fame, that patient is taken to the imaging department where a MRI or CT imaging scan is performed of the patient’s head. For patients undergoing treatment for a vascular condition, an angiography (an imaging procedure to view blood vessels) may be performed. Data from the imaging study is then transferred to the Gamma Knife treatment planning computer.
- Treatment planning: After imaging and while the patient rests, the Gamma Knife treatment team, which includes a neurosurgeon, a radiation oncologist and a physicist, develops the custom treatment plan for the patient. Depending on the complexity and location of the condition being treated, planning can take up to an hour or more.
- Treatment: Once the treatment plan is completed, the patient will enter the Gamma Knife suite and recline on the unit’s treatment table. The head frame is fixed to the Gamma Knife unit, and team performs the necessary safety checks. The patient is then moved head first into the machine and treatment begins. Actual treatment time varies depending on the condition treated but can range from about 15 – 20 minutes to an hour or more. During the treatment, the patient does not see or feel the treatment as its being delivered. Patients can communicate with the treatment team through closed circuit TV systems or listen to music. Some patients are so relaxed that they actually fall asleep.
- Post Treatment and Follow Up: Once the treatment is complete, the patient is moved out of the Gamma Knife and the head frame is removed. Since the majority of Gamma Knife procedures are performed as an outpatient basis, patients are given the necessary follow-up instructions and observed for a period of time before being released. Some patients are admitted for a brief stay in the hospital. Patients can return to their pretreatment activities and an active lifestyle within 24 – 72 hours.