 Gamma Knife
Frequently Asked Questions
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What is a Gamma Knife?
The Gamma Knife is not actually a knife at all. It is a
stereotactic radiosurgical device that non-invasively treats
malignant and benign brain tumors,
vascular malformations and
trigeminal neuralgia in a single patient visit. Patients
are treated on an out-patient basis or may require a rare
overnight hospital stay.
How does the Gamma Knife work?
Utilizing advanced diagnostic imaging and
three-dimensional treatment planning software, Gamma Knife
delivers 201 precisely focused beams of gamma radiation to
small targets inside the brain. Radiation is only delivered
at a single, finely focused point where all 201 beams
converge to treat the diseased tissue, while nearby healthy
tissue is spared.
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What are the benefits?
Gamma Knife
radiosurgery has several benefits that make a better
form of treatment for some conditions when compared to
conventional radiation therapy and surgery. Gamma Knife
differs from conventional radiation therapy of the brain in
that the radiation in Gamma Knife treatment is only directed
to small, targeted areas, sparing surrounding normal brain
tissue. This technology allows for non-invasive treatment to
be performed with extreme precision, targeting only the
abnormality in the brain. Another benefit of Gamma Knife is
that treatment is done entirely in one day rather than many
treatments over several weeks, and the treatment often may
be repeated if necessary. Gamma Knife
radiosurgery also greatly reduces the risks and
complications associated with open brain surgery, due to the
absence of general anesthesia and surgical incision.
Gamma Knife treatment can also replace brain surgery in
some patients with brain tumors and
vascular malformations. An individual who would be at
risk for complications from conventional surgery may be a
candidate for Gamma Knife surgery. Or, it can be used when
prior surgery or radiation therapy has failed to control the
disease process. It can also be used in conjunction with
conventional surgery in previously inoperable cases. It is
bloodless, virtually painless, with no loss of hair and
rapid return to pre-treatment activities, and has excellent,
well-documented clinical outcomes.
What if I am older or have other medical conditions?
Gamma Knife radiosurgery is especially valuable for
patients whose neurological disorders require a difficult
surgical approach or may be impossible to treat using
conventional neurosurgical techniques. Patients of advanced
age or in poor medical condition can be at an unacceptably
high risk for anesthesia and conventional surgery, making
Gamma Knife treatment an ideal solution. Gamma Knife
technology also is highly beneficial for patients whose
lesions are situated in an inaccessible or functionally
critical area within the brain. In addition, the treatment
can be used as an
adjunct to the care of a patient who has undergone
conventional brain surgery, interventional neuroradiology or
conventional radiation therapy or chemotherapy.
What conditions can be treated by the Gamma Knife?
Conditions for which the Gamma Knife is considered are:
Malignant tumors such as:
-
Metastases
-
Malignant gliomas
Benign tumors such as:
Vascular malformations such as:
Functional disorders such as:
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How are patients referred for Gamma Knife treatment?
Most patients are referred to the Gamma Knife program by
their doctors. However, some make self-referrals. The Gamma
Knife team reviews each patient's records to determine if
Gamma Knife treatment would be advantageous.
What information is used to determine if Gamma Knife
treatment is appropriate?
-
Medical and Surgical History
-
Clinical Examinations
-
Imaging studies, such as
MRI,
CT and/or
PET scans
Is Gamma Knife treatment effective?
The Gamma Knife’s success rate is impressive. Supported
by more than two decades of clinical research, this
neurosurgical tool has met with unprecedented results.
Clinical applications continue to grow, and its many
benefits as a non-invasive treatment modality continue to
make it the treatment of choice for certain clinical
conditions. Clinical abstracts are provided for additional
information.
What happens during Gamma Knife treatment?
First, a lightweight frame is attached to the patient’s
head. Local anesthesia is used before the frame is secured
in place. The patient then has an
MRI
imaging study or, in the case of an
arteriovenous malformation,
angiography, may be needed in order to precisely locate
the abnormal area. Data from the imaging study is
transferred into the treatment planning computer. While the
patient rests, the treatment team (a neurosurgeon, radiation
oncologist and medical physicist) uses advanced software to
determine the treatment plan. This takes one or two hours to
complete, depending on the complexity and location of the
disease. When the individual treatment plan is completed,
the patient is placed on the Gamma Knife couch and precisely
positioned. The patient is then moved automatically, head
first into the machine, and treatment begins. Treatment
typically lasts from 15 minutes to an hour, during which
time the patient feels nothing unusual. Following treatment,
the patient is automatically moved out of the machine, and
the head frame is removed.
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What will I feel during Gamma Knife Treatment?
Patients typically feel slight discomfort from the local
anesthetic used prior to head frame placement, and have
reported feeling pressure for a short time while the pins
are inserted to fixate the head frame -- but no pain. The
patient does not see or feel the radiation during treatment.
Will I be awake during the procedure?
The patient remains conscious throughout the entire
procedure, and may communicate with the treatment team.
Will my head be shaved?
No, the head is not shaved. In rare cases the treatment
may cause some hair loss.
What can I expect after the treatment?
When the treatment is finished, the head frame will be
removed. Sometimes there is a little bleeding from where the
pins were attached to the head. In this case, gauze and
pressure will be applied to stop the bleeding and keep the
area clean. A temporary head dressing is placed to keep the
pin sites clean. It is recommended that the patient take it
easy over the next 12 to 24 hours. Pre-Gamma Knife
activities can be resumed within a few days.
Is Gamma Knife treatment safe?
The Gamma Knife allows non-invasive brain surgery to be
performed with extreme precision while sparing healthy
tissues surrounding the targeted treatment area. Also,
because neither a surgical incision nor general anesthesia
is required, the risks usually involved with open brain
surgery, such as hemorrhage or infection, may be reduced.
Hospitalization is rarely required and recovery time is
minimal. While individual patient outcomes may vary,
patients may resume their normal pre-surgery lifestyle
within a few days.
How quickly will the treatment work?
The effects of Gamma Knife radiosurgery occur over
several days to several years, depending on the type of
medical condition treated. The radiation alters the DNA of
the tumor or lesion being treated so that the cells no
longer reproduce, eventually rendering the lesion inert.
Some abnormalities dissolve gradually, eventually
disappearing. Others simply exhibit no further growth. The
effectiveness of the treatment is monitored by MRI scans at
regular intervals. The goal of radiosurgery is tumor
control, which is defined as stable tumor size or tumor
shrinkage.
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What are the complications of Gamma Knife treatment?
Early complications may include:
Common side effects:
Delayed complications may include:
-
Uncommon complications:
-
Local loss of hair in superficial lesions
-
Local brain swelling in the treatment site
-
Local
necrosis in the treatment site
When can I return to my normal activities?
Within a few days. The only restrictions you will have
are the same you had prior to your treatment.
Is Gamma Knife treatment more or less expensive than
traditional brain surgery?
Cost studies have shown Gamma Knife radiosurgery to be
less expensive than conventional neurosurgery because it
eliminates lengthy post-surgical hospital stays, expensive
medication and potentially months of rehabilitation.
Importantly, there are virtually no post-surgical disability
and convalescent costs with this procedure.
Will my insurance cover this procedure?
Gamma Knife radiosurgery is reimbursed by most insurance
companies, PPOs, HMOs and Medicare.
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