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| What is a Gamma Knife? |
The Gamma Knife is not a knife, but a sophisticated technology
that can in some situations replace the surgeon's scalpel with a single, high
dose of gamma radiation. It consists of a lightweight head frame; a helmet called
a collimator, and the radiation unit itself.
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| How does the Gamma Knife work? |
| Through advanced imaging and three-dimensional planning
techniques, Gamma Knife Radiosurgery delivers multiple, very narrow beams of
gamma radiation to small targets inside the brain. It does so by sending radiation
beams through 201 holes in a device called a collimator helmet. Only at the point
where all 201 beams converge at a single, finely focused point is enough radiation
delivered to treat the diseased tissue while nearby healthy tissue is spared. |
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| What is Gamma Knife Radiosurgery? |
The Gamma Knife replaces the surgeon's scalpel with a
single, high dose of radiation. Like the surgeon's scalpel, the radiation eradicates
the diseased area with a safe and effective approach. The patient wears a light
weight head frame that attaches to a helmet, through which radiation is precisely
focused at a single target. Only the tissue being treated receives a very strong
dose of radiation while the surrounding tissue remains unharmed. The painless,
bloodless procedure is usually performed under local anesthesia with mild sedation.
Although the entire procedure takes several hours, the actual treatment takes
just 15 minutes to one hour, depending on the size of the lesion being treated.
If there are multiple tumors or if the tumor spreads to another area, radiosurgery
can be repeated. There is no risk of surgical complications like infection, hemorrhage
or leakage of cerebral spinal fluid.
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| What are the benefits? |
Gamma Knife surgery is different from conventional radiation
therapy of the brain because it is only directed to the target and spares unnecessary
treatment of adjacent, normal brain tissue.
It differs because only a one day treatment is required rather than many treatments
over several weeks and can be repeated if necessary.
It can be used in conjunction with conventional surgery as a boost and can be
used in previously inoperable cases.
Gamma Knife surgery can replace brain surgery in some patients with brain tumors
and vascular malformations.
An individual who would be at risk for complications by conventional surgery
may be a candidate for Gamma Knife surgery.
It can be used when prior surgery or radiation therapy has failed to control
the disease process.
It can be used in conjunction with conventional surgery as a boost and can be
used in cases previously considered inoperable.
It is _ to 1/3 the cost of conventional neurosurgery.
It is bloodless, virtually painless, no loss of hair with rapid return to activities
of every day living.
Excellent, well-documented clinical outcomes. |
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| What if I am older or have other
medical conditions? |
| Gamma Knife radiosurgery is especially valuable for patients
whose neurologic disorders require a difficult surgical approach or may be impossible
by 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 brain surgery,
interventional neuroradiology, or conventional radiation therapy or chemotherapy. |
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| What are the indications treated
by the Gamma Knife? |
Potential candidates are reviewed by a multi-disciplinary
panel of professionals for the following:
- Medical history
- Clinical examinations
- Imaging studies
- Previous surgeries and treatments
Conditions for which the Gamma Knife is considered are:
Benign tumors such as
- meningiomas
- acoustic neuromas
- pituitary tumors
- low grade glioma and skull based tumors
Malignant tumors such as:
metastases and malignant gliomas
It can be an effective treatment for vascular malformations such as
- arteriovenous malformations
- cavernous angiomas
And it can treat functional disorders such as
- trigeminal neuralgia
- parkinsons disease
- essential tremors
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| How are patients referred for
Gamma Knife treatment? |
| Most patients are referred by their doctors to the Gamma
Knife program. Many patients make self-referrals. The Gamma Knife team meets
and looks at each patient's records to determine if Gamma Knife treatment would
be advantageous to the needs of the patient. |
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| What test are needed to determine
if a patient would be appropriate for Gamma Knife? |
- Medical and Surgical History
- Clinical Examinations
- Imaging Studies, such as MRI and CT and PET scans
- Function Studies
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| Is the Gamma Knife treatment effective? |
| The success rate of the Gamma Knife is impressive. Supported
by two decades of clinical research, this neurosurgical tool has meet 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 in certain clinical
conditions. |
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| What is involved in a Gamma Knife
treatment? |
On the day of treatment, the patient will have a lightweight
frame attached to the head. Local anesthesia is used before the frame is secured
in place. The frame is used in conjunction with an imaging procedure to accurately
locate the diseased area. With the frame in place, the patient either has an
MRI or CT imaging study or, in the case of an arteriovenous malformation (AVM),
angiography, in order to precisely locate the diseased area to be treated. Data
from the imaging study is transferred into the treatment planning computer. While
the patient rests, the treatment team (which consists of a neurosurgeon, radiation
oncologist and 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. At the completion of the treatment, the patient is automatically
moved out of the machine, and the head frame is removed. The patient may remain
in the hospital overnight for observation.
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| What will I feel during the Gamma
Knife Treatment? |
| There is a slight discomfort from the local anesthetic
used prior to frame placement. Patients have reported that they feel pressure
when the pins are inserted but no pain. The pressure can be a little uncomfortable
but id does not last for long. Anesthetic is used so the patient will have very
little discomfort. The patient does not see or feel the radiation during treatment. |
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| Will the patient be awake during
the procedure? |
| The patient remains conscious throughout the entire procedure,
and may communicate with the treatment team. |
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| Will the patient's head be shaved? |
| No, the head is not shaved, in rare cases, the treatment
may cause some hair loss. |
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| What can the patient expect after
the treatment? |
When the treatment session is finished, the head frame
will be removed. Sometimes there is a little bleeding from where the pins were
attached to the head. Gauze and pressure will be applied to stop the bleeding
and keep the area clean. A small Band-Aid is placed over the pin locations. It
is recommended that the patient take it easy over the next 12-24 hours. Normal
activities can be resumed within a few days.
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| 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 surgical incision is not required, the
risks usually involved with open brain surgery, such as hemorrhage or infection,
may be reduced. Hospitalization and recovery time are minimal. While individual
patient outcomes may vary, patients may resume their normal pre-surgery lifestyle
within a few days. |
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| How quickly will the treatment
work? |
| The effects of Gamma Knife radiosurgery occur over a period
of time that can range from several day 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 radiosurgery? |
| Early complications may include:
Common complications:
- Local pain and swelling in the scalp
- Headache
Rare complications:
- Skin reddening and irritation
- Nausea
- Seizure
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
- Rare complications:
- Visual loss (dependent on diagnosis)
- Hearing loss (dependent on diagnosis)
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| 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 sometimes months of rehabilitation.
Importantly, there are virtually no post-surgical disability and convalescent
costs with this procedure. Gamma Knife radiosurgery is reimbursed by most insurance
companies, PPOs, HMOs and Medicare. |
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| 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. |
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| Will my insurance cover this
procedure? |
| Gamma Knife radiosurgery is reimbursed by most insurance
companies, PPOs, HMOs and Medicare. |
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| What will I feel during the Gamma
Knife Treatment? |
| There is a slight discomfort from the local anesthetic
used prior to frame placement. Patients have reported that they feel pressure
when the pins are inserted but no pain. The pressure can be a little uncomfortable
but it does not last for long. Anesthetic is used so the patient will have very
little discomfort. The patient does not see or feel the radiation during treatment. |
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