What is Gamma Knife?
The Gamma Knife Perfexion, a non-invasive stereotactic radiosurgical tool, is an alternative or supplemental treatment to traditional brain surgery. Gamma Knife is used to precisely target malignant and benign brain tumors and disorders with finely-focused radiation beams that minimize damage of healthy brain tissue. The procedure typically is performed in a single outpatient treatment session with considerably reduced treatment times and minimized surgical complications.
How does Gamma Knife work?
Gamma Knife utilizes the latest advanced diagnostic imaging and three-dimensional treatment planning software to deliver 192 finely-focused beams of gamma radiation to small targets inside the brain. The beams converge at a point to treat the affected tissue, while minimizing the damage of healthy brain tissue.
What are the benefits of Gamma Knife?
Gamma Knife Perfexion treatment has many benefits. It is bloodless, virtually painless, no loss of hair and rapid return to pre-treatment activities. Gamma Knife therapy may be suggested as an adjunct to standard neurosurgical therapy or as the preferred course of treatment when further traditional therapy is not recommended.
Gamma Knife treatment may also replace brain surgery in some patients with brain tumors, vascular malformations and facial pain. An individual who would be at risk for complications from conventional surgery may be a candidate for Gamma Knife radiosurgery. Gamma Knife treatment 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, other forms of radiation therapy and chemotherapy.
The benefits of Gamma Knife Perfexion treatment differs from conventional radiation therapy of the brain because it is only directed to targeted areas and spares unnecessary treatment of adjacent, normal brain tissue. Only a one-day treatment is required rather than many treatments over several weeks, and the treatment often can be repeated if necessary.
What if I am older or have other medical conditions?
Gamma Knife Perfexion 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 Perfexion 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 are treated by Gamma Knife therapy?
- Malignant Tumors: metastatic tumors (cancer spread to the brain), gliomas, chondrosarcoma
- Benign Tumors: acoustic neuromas (vesibular schwannomas), meningiomas, pituitary adenomas, low grade glioma and skull based tumors
- Vascular Abnormalities: arteriovenous malformations (AVMs), cavernous angiomas (cavernous malformations)
- Functional Disorders: trigeminal neuralgia (also known as tic douloureux or chronic facial pain)
What candidates are treated by Gamma Knife therapy?
- Patients with brain tumors
- Patients with vascular disorders
- Patients who are not candidates for conventional neurosurgery or radiation therapy
- Additional therapy for patients who have already undergone surgery, chemotherapy or radiation and require further treatment
- Gamma Knife Perfexion may also be recommended for patients with these conditions:
- Tumors or vascular malformations that are surgically inaccessible
- Risk factors that make surgery inadvisable
- Need for an additional dose of radiation following radiation therapy
- Recurrent tumors
- Facial Pain
How are patients referred for Gamma Knife Perfexion treatment?
Most patients are referred to the Fort Sanders Regional Gamma Knife Center at Thompson Cancer Survival Center by their doctors. However, some make self-referrals. The Gamma Knife team reviews each patient’s records to determine if Gamma Knife treatment is appropriate.
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 Perfexion treatment effective?
The Gamma Knife’s success rate is impressive. Supported by more than three 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. This does not include research indications.
What happens during treatment?
Once a patient’s condition is reviewed by our multidisciplinary team and Gamma Knife treatment is deemed appropriate, the patient will be scheduled for treatment. On the day of treatment, there are several steps that take place.
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 a MRI imaging study or, in the case of an arteriovenous malformation, an angiography may be needed in order to precisely locate the disease 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 physicist) uses advanced software to determine the treatment plan. This takes one to 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 or more, during which time the patient feels nothing unusual. Actual treatment time varies based on the condition being treated and its location.
Following treatment, the patient is automatically moved out of the machine, and the head frame is removed. Gamma Knife treatment is usually an outpatient procedure, but some cases may require an overnight stay. If a patient is treated on an outpatient basis, he or she will be observed for a period of time and released. If the procedure has been designated as inpatient, then the patient will be admitted to the hospital.
What will I feel?
During the actual procedure, the patient does not see or feel the radiation during treatment. Before treatment takes place, 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.
Will I be awake during the procedure?
The patient remains conscious throughout the entire procedure and may communicate with the treatment team through a two-way microphone. The treatment team monitors the patient during treatment by video and sound.
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 treatment?
When 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 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 Perfexion treatment safe?
The Gamma Knife Perfexion 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-treatment 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 static. 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. For vascular malformations, control is generally considered total obliteration.
What are the complications of Gamma Knife Perfexion treatment?
Early complications may include:
Common side effects:
- Local pain and swelling in the scalp
- Skin reddening and irritation
Delayed complications may include:
- Local loss of hair in superficial lesions
- Local brain swelling in the treatment site
- Local tissue necrosis in the treatment site
- Visual loss (dependent on diagnosis and areas treated)
- Hearing loss (dependent on diagnosis and areas treated)
When can I return to my normal activities?
Most patients typically return to pre-treatment 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 that 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.