Radiosurgery / Gamma Knife / Cyberknife
Previously, many disorders of the brain and spinal cord could only be treated with open surgery. With the advent of radiosurgery, many problems can be addressed with this outpatient, minimally invasive treatment option.
In radiosurgery, computerized localization techniques permit delivery of a large dose of radiation to a well-defined, precisely targeted region. This technique can deliver a large dose of radiation to the tumor while minimizing radiation of normal tissue. Radiosurgery is most useful for small tumors, AVMs and some lesions that are difficult to remove surgically. Research scientists continue to examine whether this technique can help patients with other procedures as well.
The Gamma Knife and the Cyberknife are two types of radiation machines used for a procedure known technically as stereotactic radiosurgery, combining precise stereotactic guidance and a sharply focused beam of radiation energy to deliver a single, precise dose of radiation. The focusing accuracy is within 0.5 millimeters, far more precise than other types of radiation therapy. Despite its name, the Gamma Knife does not require a surgical incision. It is a non-invasive tool that replaces the scalpel (or surgery) with a focused array of 201 intersecting beams of high-intensity gamma radiation.
How does it work?
Radiosurgery uses a focused dose of radiation to stop the growth of abnormal tissue. This focused radiation destroys the DNA mapping of the cells and renders them unable to divide. By delivering the radiation from many angles, evenly distributed around the patient’s head, radiosurgery targets the tumor or vascular malformation with three-dimensional precision.
The beams of radiation are focused on the abnormal tissue area, with the area of their intersection conforming to the size and shape of the target. Each of the individual beams provides a relatively small, harmless dose of radiation. Only at the point where the narrow beams converge is the radiation at its most powerful. Thus, both the Gamma Knife and Cyberknife prevent injury of the surrounding normal brain. This avoids the significant risk of memory and cognitive impairment seen when conventional radiotherapy is used.
Gamma Knife procedures are done at St. Anthony Central Hospital, a member of Centura Health. This center has done over 2500 cases, more than almost any other in the country. The only Cyberknife center in Colorado is located in Boulder.
