Patients are generally able to come home the same day, and it is rare to require admission for the radiosurgery procedure, itself.

The Gamma Knife is one method of performing radiosurgery. It is a device that precisely aims multiple concentrated beams of radiation at brain lesions. The Gamma Knife directs gamma-ray radiation from up to 201 sources of radioactive cobalt. Each radiation beam has a relatively low amount of energy. However, when 201 beams intersect into a tight grouping on the target tissue, the energy is magnified. The target can be quite small, from several millimeters to three centimeters in diameter, with minimal impact on surrounding tissue due to the rapid drop-off in energy outside the isocenter (target zone).

The Gamma Knife uses a rigid stereotactic frame (technology that allows the surgeon to position the patient’s head very precisely). The frame is affixed to the skull to immobilize the head. The Gamma Knife is then programmed to precisely change the beams to deliver desired energy to the treatment site. Patients experience relatively little discomfort and the treatment session may range from 15 minutes to several hours depending on the nature of the disease. The Gamma Knife unit is located in a specially designed room equipped with television monitoring and two-way voice communication, so the physician can see and converse with the patient during treatment.

Radiosurgery technology can be used to treat a variety of conditions, including:

• Benign (non-cancer) tumors
• Malignant (cancer) skull tumors
• Acoustic neuromas
• Pituitary adenomas
• Pinealomas
• Craniopharyngiomas
• Meningiomas
• Chordomas
• Chondrosarcomas
• Glial tumors
• Abnormal vascular formations (artery, vein)
• Arteriovenous malformations or AVMs
• Functional disorders
• Trigeminal neuralgia
• Parkinson’s disease
• Epilepsy
• Intractable pain

When treating a tumor or lesion, the Gamma Knife does not remove the tumor or lesion. Instead, the treatment disrupts the tumor’s DNA, which interferes with its ability to survive.

The main difference between the Cyberknife and Gamma Knife is that the Cyberknife does not require a frame mounted to the patient’s head. Instead, it is a non-invasive treatment in which patients lie on a treatment table while the radiation system, which is mounted on a robotic arm, moves around him or her. Gamma Knife is used to treat cancers inside the skull, while Cyberknife is capable of treating lesions from head to toe. Gamma Knife is generally more accurate for small, complex brain lesions, and Cyberknife’s frameless system can treat larger lesions in more locations. Cyberknife can also be used to treat patients on successive days (fractionation), allowing larger doses over a more extended period.

The side effects of radiosurgery treatment may include swelling or (rarely) necrosis (tissue death). If swelling does occur, steroids may be administered to reduce inflammation within the tumor or lesion cavity. Your doctor will carefully monitor for side effects and will treat them promptly if they arise.

• Radiosurgery avoids the physical trauma and other risks associated with conventional open brain surgery. These include spinal fluid leaks, nerve dysfunction, infection and heart or lung problems.
• The radiosurgery’s accuracy spares surrounding tissue and targets treatment to a small, specified area.
• For patients who are ill, infirm or elderly, or for those being treated for recurring tumors or residual tumors, open-skull surgery may not be an option. Radiosurgery is a safer alternative, in many of these cases.
• Some tumors or lesions are inaccessible, and radiosurgery may be used to treat these disorders.
• Complications from general anesthesia are avoided since the patient only needs mild sedation.
• Most patients will not require overnight hospitalization.