New Procedures

Radiosurgery for Intracranial and Spinal Lesions

Introduction

Surgery, chemotherapy, radiotherapy, radiosurgery or combinations of these methods are all valuable CNS tumor treatments, depending upon the specific situation. In particular, radiosurgery, a technique where very high doses of ionizing radiation are precisely directed toward a target lesion, is a very actively evolving treatment method. The goals of radiosurgery are symptom relief, local tumor ablation, and potentially longer survival. While the procedure does not remove a tumor, it typically destroys malignant cells and stops the growth of active tissue within the nervous system.

In stereotactic radiosurgery, high dose focused radiation beams are directed through a tumor volume, from up to hundreds of different angles. With the original radiosurgical system, the Gamma Knife, a metal frame is attached to the patient’s head to immobilize the patient during treatment. Wearing this head frame is arduous and uncomfortable, limiting the potential application of the Gamma Knife to single treatments, used against lesions within the brain or skull base.

CyberKnife® Overview

In contrast to Gamma Knife, the CyberKnife® system is noninvasive, using a sophisticated artificial intelligence feedback loop image guidance system to continuously update the target lesion location, and therefore has much broader clinical applications for radiosurgery both within and beyond the brain. In addition to effectively treating lesions within the brain and skull base, CyberKnife® is extremely powerful and valuable against spinal lesions, which may otherwise be very challenging to treat. Because CyberKnife® sharply sculpts dose and minimizes normal tissue radiation exposure compared with other systems, it is also capable of safely and effectively treating recurrent lesions in the brain, spine or elsewhere in the body, even after conventional radiation therapy has failed in the same location.

CyberKnife® Mechanism

The technologically sophisticated CyberKnife® System utilizes two angled X-ray imagers to stereotactically localize reference anatomy within the patient in or near the target lesion, feeding those coordinates into the targeting computer, which then directs the robotic arm manipulator to move the compact linear accelerator with six degrees of freedom, aiming at the lesion with sub-millimeter precision. With its range of motion, the robotic manipulator is capable of positioning the linear accelerator through an infinite number of beam positions, creating extremely conformal and potent radiation distribution patterns. The continuously updated image guidance system keeps the beams on target throughout the entire procedure, with comparable precision to frame-based systems such as the Gamma Knife.

Clinical Benefit

CyberKnife® does not present the same problems as traditional surgery, because there is no actual incision, but rather, a focusing of therapeutic radiation with a “surgical-like” margin. There is no anesthesia and the risk of infection and hemorrhaging is therefore eliminated. In contradistinction to traditional radiotherapy, the CyberKnife® system is capable of more effectively sparing healthy tissue that surrounds the targeted area, opening a new paradigm of potential treatments.

CyberKnife Demonstration Video

CyberKnife® Treatment Process

The CyberKnife® treatment itself is painless; normally taking about an hour, though the exact time may vary considerably, depending upon the exact situation. Patients often bring music CDs or books on CD to play in our music system while their treatment progresses. A mild sedative may be offered before the treatment, though this is usually optional. Following Cyberknife radiosurgery for treatment of a lesion within the head or spine, the patient returns home the same day.  Mild fatigue is common, but other problems are unusual. Nonetheless, a patient or their family should report any symptoms or problems to their CyberKnife® medical team.  Patients who are on anti-seizure and/or steroid anti-inflammatory medication will remain on these unless medications unless specifically advised to do otherwise by their neurosurgeon or radiation oncologist.  Hair loss is not common, though may occur depending upon the exact location of the lesion relative to the scalp. If hair loss does occur, it is usually limited to small portions of the scalp. 

Summary

Cyberknife® radiosurgery is the most advanced form of radiosurgery available and is also more patient friendly than predecessor radiosurgical systems. Its flexibility is unparalleled and its effectiveness gives hope to many patients that previously may have had more limited options available to them.

For more information about CyberKnife, visit sdcyberknife.com