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Gamma Knife

Gamma Knife Procedure


Patient selection for treatment is made by members of the Gamma Knife team on an individual case basis. Factors considered in the selection process include existing imaging studies, medical history, patient age, and health.


The Gamma Knife treatment procedure is a four-step approach carried out by various members of the Gamma Knife Team. It consists of frame fixation, imaging, and digital treatment planning, followed by the acutal Gamma Knife Radiosurgery.


Step 1:  Frame Fixation

The Leksell Stereotactic System model “G” frame is affixed to the patient’s head via adjustable screws and posts. IV sedation and local anesthesia is provided. General anesthesia is not used except in cases involving small children.


The frame is the medium through which target coordinates are determined, and serves the dual purpose of immobilizing the patient’s head within the collimator helmet during treatment.


Step 2: Imaging

Patients will be having another imaging scan. Neuroimaging studies such as MRI, cerebral angiography, and CT scans, are performed by the team’s radiologist.The images, which contain reference points provided by the stereotactic frame, are taken in overlapping sequences. When combined, these multiple imaging studies produce the x, y, and z coordinates that form the basis of the Leksell GammaPlan 3-D modeling and treatment planning system.



Step 3: Treatment Planning

This process takes 1-2 hours. Patients are able to be with family and/or watch television. The sophisticated treatment planning software develops an individualized radiation dosage. In both 2 and 3-D models, isocenters are located and the precise 3-D geometry of the lesion is defined.


The Leksell GammaPlan version 5.3 calculates the total dosage and treatment times, which can be further tailored by the specialist. When the customized plan is finalized, the patient is brought in for treatment.



Step 4: Gamma Knife Radiosurgery

The patient will lie on the table and listen to music during the procedure. There is no pain or sensation felt by the patient. The procedure will take from 30 minutes to two hours.  





Before the Procedure


Prior to Gamma Knife treatment, patients are asked to:


            •  Arrange for transportation

            •  Limit physical activity

            •  Wash their hair

            •  Cease eating and drinking at

               midnight the night before treatment

            •  Attend a Pre-op appointment to

               complete labs and paperwork

            •  Patients may tour the Gamma Knife




The day of the treatment, it is requested that the patient:


            •  Arrive 15 to 30 minutes early

            •  Check in time is usually 6 a.m.

            •  Refrain from wearing make-up or

               nail polish

            •  Remove all jewelry, accessories,

               and/or prostheses

            •  Have a friend or relative

               accompany them