Through her research at the National Institute of Health's web site Gail became
suspicious that the headaches she had suffered for the past 30 years sounded strangely like potential symptoms
related to an AVM. An MRI scan conformed that she too had an arteriovenous malformation. Because her lesion was
easily accessible, surgery was the treatment of choice. After successful removal of the lesion in November 1998,
 |
| Allen Drabicki says that the Gamma Knife procedure
has given him an optimistic outlook on the future. |
she spent the next two months recovering.
Drabicki's situation was more complicated because of the location of his lesion.
While traditional surgery was an option, evaluation by neurosurgeon Stephen Tatter, M.D., Ph.D. and radiation oncologist
Edward Shaw, M.D., determined Drabicki to be an appropriate candidate for a non-invasive gamma knife radiosurgical
procedure. One of the first patients to be treated at Wake Forest University Baptist Medical Center with
the Leksell Gamma Knife, he was treated and released on September 1.
Several days later he reported that in spite of the occasional headache, he was
"doing great and healing well."
A Tool with a Promising Future
PRECISE AND POWERFUL, the 22-ton Gamma Knife was delivered to the Medical Center
in July, 1999. The first procedures at North Carolina's only Gamma Knife Radiosurgery Unit were performed
August 31. Based on over 30 years of clinical experience, Gamma Knife radiosurgery has become the treatment
of choice for selected lesions in the brain as an alternative to conventional open surgery.
The unit aims 201 narrow "pencil beams" of radioactive cobalt-60 at
targets from several millimeters to 5 centimeters (2 inches) in diameter. The beams focus precisely on the
target tissue, minimizing the effects on surrounding brain tissues.
Some of the most common indications for treatment include:
Stephen Tatter, assistant professor of
neurosurgery and co-director of the Gamma Knife Program says, "It's becoming clear that this is the treatment
of choice for multiple brain metastases. There is a significant chance that Gamma Knife radiosurgery can eliminate
brain metastases as a cause of death in a cancer patient afflicted with this problem."
 |
| Drs. Stephen Tatter and Edward Shaw prepare a patient for
Gamma Knife radiosurgery. |
In fact, a recent randomized study demonstrates a six-fold benefit of the Gamma Knife in treating people with multiple
brain metastases.
Ed Shaw, chairman of the Department of
Radiation Oncology and co-director of the Gamma Knife Program, was instrumental in bringing gamma knife radiosurgery
to Wake Forest. He established a similar program at the Mayo Clinic in 1990, and is an ardent advocate of
its potential.
"Gamma Knife radiosurgery will play
an increasing role as a non-surgical, non-invasive way of treating both benign and malignant brain tumors,"
says Shaw.
According to Shaw, there are several benefits
to Gamma Knife radiosurgery as compared to radiosurgery using linear accelerators. The Gamma Knife allows
the use of many more spheres of radiation to fill the lesion, making dose distributions conform much more precisely
to the lesions compared to linear accelerators. Because radiation is more concentrated only at the target
area, the surrounding brain tissue. has the greatest chance of being spared from harmful after-effects. The
Gamma Knife is especially useful when conventional surgical techniques would pose high risk, such as in the presence
of other illnesses or when a patient's age prohibits standard surgery.
Shaw was the principal investigator in
a study conducted by the Radiation Therapy Oncology Group (RTOG) that found people with recurrent brain tumors
treated with Gamma Knife radiosurgery are three times more likely to have success than those treated with linear
accelerator radiosurgery.
Outpatient "Brain Surgery"
MORE THAN 50,000 patients have been treated
worldwide with Gamma Knife radiosurgery with no mortality related to the procedure. In most cases the procedure
can be done as an outpatient with the patient returning home the same dav.
In a typical scenario, both the neurosurgeon
and radiation oncologist evaluate patients (along with prior imaging studies and records) to determine if they
are appropriate candidates for the procedure. On the morning of the procedure, a mechanical guiding device
called a stereotactic head frame is attached to the patient's head. The location of the tumor and the surrounding
normal tissue is evaluated with imaging technology such as computed tomography (CT), angiography, and/or magnetic
resonance imaging (MRI). Next, the team of neurosurgeons, radiation oncologists and radiation physicists
works together to plan the Gamma Knife procedure so it precisely treats the target lesion.
The patient's head is then placed into
the Gamma Knife, a large helmet-like device with 201 openings that focus the narrowbeams of radiation onto the
target in the brain. The dose of radiation each patient receives is selected by the neurosurgeon and radiation
oncologist depending on the type and location of each lesion. The radiation treatment session usually lasts
30 to 60 minutes, and up to several hours for very complex cases. Following the completion of radiosurgery,
the head frame is removed and the patient is sent home with only two bandaids on the forehead to show for the entire
procedure.
Gamma Knife treatment causes few of the
immediate side effects that are associated with conventional external beam radiation. Fatigue, hair loss,
nausea, vomiting and headaches rarely occur; and few infections, hemorrhages or other standard neurological complications
have been reported as a result of Gamma Knife procedures. Patients usually return home the same day and return
to their normal schedule within a day or so.
While results are not as immediate as with surgery, the prognosis
is promising. With AVMS, the expectation is complete obliteration of 80 percent of the treated lesions within
two years. Certain tumors, like acoustic neuromas and meningiomas stop growing over 95 percent of the time.
One of the most rewarding aspects of this
treatment, says neurosurgeon Charles Branch, M.D., who began the radiosurgery program at the Medical Center in
1990, is that, "There is a population of people for whom this technology offers the ability to maintain or
improve quality of life. People with lesions that were considered inoperable or with health issues which
made them poor candidates for surgery are good candidates for this procedure."
The Gamma Knife is also an alternative
to conventional open surgery. For instance it is used for trigeminal neuralgia (severe facial pain) as an
alternative to open microvascular decompression surgery and has the advantage of eliminating the pain without making
the face numb, a sometimes disabling complication of surgery the most common type of surgery, radiofrequency lesioning.
"The Gamma Knife represents one of the most exciting and potentially beneficial
medical technologies for patients with benign and malignant brain lesions - many of which are inoperable,"
says Shaw. "Our goal is to continue to be one of the best brain tumor treatment and research programs in the
country. The Gamma Knife is a necessary part of the armament for this program."
