«Gamma knife»® treatment procedure includes four key stages:
The patient’s head is fixed with a stereotactic frame. The head frame is necessary to ensure high accuracy of radiation. The frame will be attached to the patient’s head with special pins after local anaesthesia is injected in the pin insertion sites.
2. Imaging studies
The location of the tumour is identified using a magnetic resonance imaging (MRI) or computed tomography (CT) scan. In case of arteriovenous malformations, an angiography can also be used. These studies help to locate the lesion as it relates to the stereotactic frame.
3. Treatment planning
After the imaging studies have been completed, the treatment team will analyse the images and devise the treatment plan. Treatment planning usually takes about two hours, during which the patient is allowed to rest and relax. At this time the doctors will decide on the optimal method and radiation dose using special computer software for the purpose of achieving the maximum effectiveness and protection of healthy tissues.
4. Treatment procedure
After all the preparatory stages are performed, the doctors can immediately proceed to the treatment. The patient’s head is fixed again using the stereotactic frame. Then the patient is placed on a special couch with a collimator helmet and moved into a radiation unit. The treatment session may last from several minutes to several hours. Usually, one session is required, but in some cases the number of procedures can be increased. During the entire session the doctors will observe the patient through video and audio devices. The treatment session is absolutely painless, and the patient remains conscious.
After the treatment
«Gamma knife»® treatment is usually well-tolerated by the patients. In some cases the patients can feel a mild headache and have a little swelling in the sites which were used to fix the frame, but they occur rather rarely. Shortly after the treatment the patient is discharged from the clinic and can resume normal activities. The only exception includes patients who underwent angiography – they need to remain in the inpatient unit for several hours. We also do not recommend driving at the day of treatment.
Since radiosurgery treatment allows stopping the growth of brain abnormalities, the positive clinical effect after «Gamma knife»® session is observed during several weeks and, in some cases, during even several months after the treatment. The progress can be monitored using computed tomography, magnetic resonance imaging or angiography. If necessary, the treating doctor will prescribe additional studies.