Penn Gamma Knife Center at Pennsylvania Hospital
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Trigeminal Neuralgia

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Q&A Sessions: Gamma Knife Questions

John Y.K. Lee, MD, Assistant Professor of Neurosurgery, is the Director of the Penn Center for Cranial Nerve Disorders and a national leader in treating cranial nerve disorders.

Jan asks:
I had Gamma Knife and no longer have any pain (seven months). I understand there is to be numbness and tingling, but is itching of the face a side effect and will any of the side effects go away or subside? Is there something I can take or apply to my face for the itching?

Dr. Lee responds:
Itching can be a side effect of Gamma Knife radiosurgery for trigeminal neuralgia. It should improve.

Rick asks:
How many Gamma Knife procedures do you perform annually at the Center? How does that compare to other centers in the region and nationally?

Dr. Lee responds:
We perform the most Gamma Knife procedures in the Delaware Valley, approximately 300 case per year.

Joanne asks:
My mother had Gamma Knife radiosurgery exactly two years ago. Unfortunately, her tumor has returned in the exact same place. Can she have the same procedure repeated?

Dr. Lee responds:
This depends on the type of tumor and location. I would be happy to review her films.

Joyce asks:
Can a tumor that is 4cm large be treated successfully with this method?

Dr. Lee responds:
Gamma Knife radiosurgery side effects are determined by:

  1. Volume
  2. Location
  3. Individual Sensitivity

A single linear dimension of 3cm can represent a small volume if it is 3cm x 1cm x 1cm. I would be happy to review the films.

Evie asks:
What are the side effects of Gamma Knife surgery please?

Dr. Lee responds:
Side effects of Gamma Knife are specific to your diagnosis and the location of treatment and dose used. Most patients who undergo Gamma Knife radiosurgery, however, have minimal side effects. They may have a little headache after the procedure, but they can go home on the same day and return to full activities by the next day. I would be happy to discuss this in more detail, if you could provide more specifics.

Lynn asks:
How much does it cost for the Gamma Knife treatment for brain cancer?

Dr. Lee responds:
Gamma Knife radiosurgery is covered by most insurance providers as well as Medicaid and Medicare. The cost without insurance varies depending on the complexity of the treatment plan.

Go asks:
In March, my mother was diagnosed with adenocarcinoma lung cancer, with one brain metastasis. She had a successful brain surgery to resect this tumor and has been on Tarceva for the past five months. She just had a scan with no trace of tumors in her brain, and the lung tumor is now inactive.

Now a radiation oncologist wants her to undergo whole brain radiation as well as lung radiation. I am not sure that her quality of life will be extremely compromised after whole brain radiation. Is this a clear benefit to her? Should we consider not having whole brain radiation? What would your opinion be in her situation?

She did see Tracey Evans back in March — Dr. Evans recommended you for the neurosurgery. My mom lives in Dallas and we decided to have the surgery done near her. She has been under the care of a lung oncologist since then. But we would be willing to have her radiation done here with you if you felt that it would be better.

Dr. Lee responds:
The role of WBXRT in the management of brain metastasis used to be quite straightforward. Everybody would get their entire brain radiated. Today with the widespread availability of good MRI scans and stereotactic radiosurgery, the role of WBXRT has changed.

I would be happy to see you and your mother in consultation to discuss treatment options further. If you have any additional questions or would like to schedule an appointment, please call us at 800-789-PENN. You can also request an appointment online.

Homi asks:
My mother has ovarian cancer that spreads to her brain while on Toxel; there are many small pockets in brain. Doctors are suggesting full head radiation. Should she use Gamma Knife? Does it work with Gamma Knife? Since she has still cancer in stomach, I worry if they take her off Toxel and work on head, the cancer would spread to other organs which are still clean. What is the solution here?

Dr. Lee responds:
In general, Gamma Knife radiosurgery is used for patients with less than five brain metastases.

Clarissa asks:
Just diagnosed with meningioma via CT Scan. Now have to decide on treatment and would obviously prefer Gamma Knife non invasive. However, I also have a pacemaker and MRI cannot be used. Can Gamma Knife procedures be done with CT as well or is MRI essential?

Dr. Lee responds:

JR asks:
A 65 year-old relative has been diagnosed with a 1 cm mass in the vermis. There is no hydrocephalus. He has no support system near him, and he is refusing open surgery at this time. Is the gamma knife appropriate?

Dr. Lee responds:
Gamma Knife radiosurgery can be done without pathologic confirmation only if the MRI findings are pathognomonic (a pathognomonic sign is a particular sign whose presence means, beyond any doubt, that a particular disease is present). In your relative's case, the MRI findings may be more difficult to interpret.

Barbara asks:
I had a Gamma Knife procedure for an acoustic neuroma about six months ago. If my follow-up MRI shows no change or slight enlargement-is this common? I heard the tumor can swell before it shrinks. How long can it take to see results?

Dr. Lee responds:
Yes, it is common at the six month MRI to see swelling. At the 12 month MRI, you should see a decrease in the size of the tumor or stability.

Kim asks:
I had a stage II oligodendroglioma fully resected about eight years ago. It came back as a stage II again and small (the tip of your finger). This tumor was also removed. They want me to do radiation. Is Gamma Knife used in situations where the tumor was fully resected?

Dr. Lee responds:
Conventional radiation with IMRT is a more common treatment strategy for your tumor.

ZlajaJ asks:
My mother had lung cancer surgery and no chemo given afterwards. This was due to excellent reports from the oncology doctor. However, it metastisized to two parts of her brain. The Gamma Knife procedure was performed. However, why can't a surgery be performed to get the lessions out?

Dr. Lee responds:
Gamma Knife radiosurgery is often an effective alternative to surgery for the management of small to medium sized brain lesions. Gamma Knife radiosurgery eliminates the need for an invasive procedure, such as craniotomy, which often poses greater overall risk to the patient.

Robert asks:
We are US citizens based in Philippines. My wife is 36 years old with no previous significant history. Onset tongue "numbness " week of May 26. Progressed to right-sided facial "numbness" by time of birth of child July 1. While in hospital post c-section, internal medicine consult found neuro exam normal except decreased (8/10) sensation to touch on right side of face.

MRI done with and without contrast. Mass in cavernous sinus on trigeminal nerve (2.1 x 1.8 x 1.5cm). Clinical opinion here of three neurosurgeons seen say meningioma or neuroma, with two out of three opting for neuroma. Stereotactic radiosurgery recommended, but at least four options of types of stereotactic radiosurgery discussed. Would like US-based opinion on appropriate intervention. Specifically why is one technique better than other for this?

Dr. Lee responds:
The Gamma Knife is inarguably the gold standard by which all other intracranial radiosurgical delivery methods are judged. Not only was it the first, it still remains the only tool that is dedicated solely to intracranial lesions, such as your cavernous sinus lesion.

Since the introduction of Gamma Knife in the 1950's, there are now many competitors that have emerged. Some of the advantages of the competitors include the fact that that they can be used to treat brain tumors as well as lung, spine, and prostate tumors. Hence, the competitors are "all-purpose" knives.

Gamma Knife stereotactic radiosurgery is extremely accurate, but it does require a frame. This stereotactic frame is light weight and is affixed to your outer skull with four pins. The frame provides exact MR correlation from planning to treatment delivery in 3D. It is with the use of this frame that Gamma Knife provides pinpoint accuracy at less than 0.5mm. Without a frame, other forms of radiosurgery may not be as accurate.

In addition, I authored the largest paper published on cavernous sinus meningioma and Gamma Knife radiosurgery. I have attached a copy of the paper for your convenience.

Stan asks:
Does this leave less possibility of cancer spreading? Also does medicare cover this?

Dr. Lee responds:
Radiosurgery typically is reimbursed by most insurance companies, PPOs, HMOs and Medicare when indicated.

Dawg asks:
Is there a certain number of brain lesions where Gamma Knife will not be used? My father has four lesions that are all about 4cm in size. Is this too many and too large?

Dr. Lee responds:
Each patient's situation is unique and there are many factors involved in determining whether Gamma Knife radiosurgery is a valuable treatment option. Four lesions is generally not too many, however, the maximum size limit is usually 3-3.5cm. I would be happy to review the case and contact you with my recommendations.

Kathy asks:
I have a 54 year-old brother with Down syndrome. He was recently diagnosed with a sella supra sellar mass 2.3 x 2.1 x 3.3 by MRI. The differential was pituitary macroadenoma.

He had to be sedated for his MRI because he freaked out (screaming and crying) as soon as he saw the MRI. Would he be a candidate for Gamma Knife radiosurgery? If so, does he have to be awake or can he be sedated? I watched your video and I don't believe he would cooperate to have the halo put on.

Dr. Lee responds:
We provide one nurse per patient and all of our nurses are trained to provide specialized care for patients undergoing Gamma Knife radiosurgery. Prior to placing the frame, patients are given medications through the IV to sedate them.

For example, one of my patients recently immediately fell asleep right before the frame placement and could not remember the procedure at all. Most patients remember some discomfort, but it is generally quite tolerable.

In addition to the medication through the IV, I use lidocaine which is injected into the pin sites and is similar to the novacaine used by dentists.

If you would like to discuss this further, please call 800-789-PENN (7366) and ask to be connected to Dr. John Y.K. Lee's office. You can also request an appointment online.

Piedropolis asks:
My brother-in-law has an agressive melanoma metastasis in the lung. Can the Gamma Knife help him?

Dr. Lee responds:
Gamma Knife is designed to be used only in the brain, and hence it is the most powerful and precise tool for brain tumors. It cannot be used to treat tumors in the lung.

Deb asks:
Exactly what types of epilepsy would you consider for Gamma Knife. I have right temporal lobe epilepsy. I ask because I'm in the process for surgery however someone mentioned this possiblity.

Dr. Lee responds:
Epilepsy has only rarely been treated with Gamma Knife radiosurgery. Each case is unique and must be carefully reviewed in full consultation with our neurologists. It is difficult for me to comment on your case based on limited information.

If you would like to discuss this further, please call 1-800-789-PENN (7366) and ask to be connected to Dr. John Y.K. Lee's office. You can also request an appointment online.

Regina asks:
Can you comment on the use of the Gamma Knife for a lung cancer tumor? Radiowave ablation was used prior twice and the second time the lung collapsed. There is a 1.9 cm tumor now.

Dr. Lee responds:
Gamma Knife is designed to be used only in the brain, and hence it is the most powerful and precise tool for brain tumors. It cannot be used to treat tumors in the lung.

Barbara asks:
If a person has a pacemaker can he still have Gamma Knife radiosurgery?

Dr. Lee responds:
I would need more information in order to answer this question. Magnetic resonance imaging (MRI) is the type of study that is typically used in planning Gamma Knife radiosurgery, and patients with cardiac pacemakers should not undergo MRI scans.

However, depending on the patient's diagnosis, there are other imaging options for Gamma Knife radiosurgery planning. For example, if the Gamma Knife radiosurgery is for treatment of a tumor, a CAT scan can be performed instead of an MRI as long as the tumor is visible on CAT scan. For trigeminal neuralgia, a CT myelogram can be used.

If you would like to discuss this further, please call us at 800-789-PENN to schedule an appointment. You can also request an appointment online.

Anne asks:
Approximately how much does the Gamma Knife procedure cost? What is the success rate for pituitary tumors?

Dr. Lee responds:
Gamma Knife radiosurgery, when necessary, is covered under most insurance policies, HMO's, Medicare, and Medicaid.

As to your second question, the management of pituitary tumors is complex depending on whether your tumor is secretory or nonsecretory, and I would be happy to discuss your case in consultation.

Please call us at 800-789-PENN to schedule an appointment. You can also request an appointment online.

Popeye asks:
I have just read about neuro-endoscopic surgery. Would this be better than the Gamma Knife? I always heard that the best way to treat cancer was to remove it.

Dr. Lee responds:
Each tool has its own uses. One does not replace another. In some cases the endoscope is an excellent tool for resection of a tumor, but in other cases a microscope is better. Similarly, Gamma Knife has its role.

Darryl asks:
My 69 year-old father was diagnosed with a desmoplastic neurotropic melanoma which mainly involves the left V2 branch of the trigeminal nerve. There is also some probable microscopic tumor involvement (based on the pathology report) of the lateral maxillary sinus mucosa.

This is a very rare tumor, and my dad does not have any evidence of a primary skin lesion. These tumors can invade nerves and travel long distances. Some of the nerve was removed, but I don't think anyone knows how much of the nerve is truly involved. He is having a lot of facial pain and numbness.

Do you have any idea if he would be a candidate for Gamma Knife surgery? He is due to start radiation therapy and possibly adjunctive chemo., but wanted to explore the possibility of gamma knife. Thanks so much for any information you could provide.

Dr. Lee responds:
I would be happy to review his films. This is a very interesting case, and Gamma Knife is definitely useful for melanoma that has spread to the brain, although this is very different.

If you would like to schedule an appointment, please call 1-800-789-PENN (7366) or request an appointment online.

Jackie asks:
My father was diagnosed with poorly differentiated squamous cell lung cancer 15 years ago. At the time he was treated with surgical resection and subsequent chemotherapy. He was symptom free for 15 years. About three months ago he developed a subtle neurologic deficit, inability to perform fine manipulations with his right hand if not under visual control. Recently he had a partial seizure.

MRI revealed eight brain metastases, two of them between 2.5 and 3 cm, the rest smaller than 1.5 cm. He feels normal except for the subtle neurologic deficit and is more interested in better quality of his remaining life than longer survival. Could Gamma Knife be considered in his case?

Dr. Lee responds:
The usual standard here would be to perform whole brain radiation therapy. Given the number of lesions, it is hard to make an argument to support Gamma Knife over whole brain radiation therapy. Nevertheless, we will be participating in a trial to compare whole brain versus Gamma Knife as an initial strategy.

Kareena asks:
My mother-in-law was supposed to be scheduled for Gamma Knife surgery but her insurance company denied the claim. She is being treated for hemingiopericytoma, the insurance company considers her treatment experimental. How can I convince the insurance to get her the coverage?

Dr. Lee responds:
Perhaps, your physician will have to write a letter. Some of the most dramatic responses are seen in tumors like hemangiopericytoma.

Joe asks:
Can you tell me if the Gamma Knife could be utilized for sacral large sacral cysts?

Dr. Lee responds:
No, Gamma Knife is a tool designed for precision in the brain.

Steve asks:
I was recently diagnosed with a 1" in diameter brain tumor and am looking at my options. Am I a candidate for Gamma Knife?

Dr. Lee responds:
You may be depending on the exact anatomic configuration of your tumor.

Stephen asks:
I am 65 years old and have just been diagnosed with a 'conventional' epidermoid cyst. Is this treatable with radiosurgery?

Dr. Lee responds:
Epidermoid cysts are generally not treated with Gamma Knife.

Cindy asks:
Why can't Gamma Knife be used for other parts of the body below the neck? Why is gamma ray chosen over X-rays then?

Dr. Lee responds:
Gamma rays are chosen, because of the particular design of the Gamma Knife. Cobalt sources work extremely well in targeting brain tumors, and they allow for extremely efficient dose delivery.

Gamma Knife is the gold standard for treating brain tumors, but it cannot treat spine, lung, or liver tumors.

Chance asks:
If I am claustrophobic, can I do this test asleep?

Dr. Lee responds:
We assign one nurse per patient throughout the entire Gamma Knife day. Hence, we can provide intravenous conscious sedation to help you with your claustrophobia.

Donna asks:
Is the Gamma Knife better than regular surgery?

Dr. Lee responds:
Both radiosurgery and conventional surgery have their respective roles. For some tumors, Gamma Knife radiosurgery can be equivalent and possibly superior to conventional surgery. Side effects from radiosurgery are usually much less than that of conventional surgery.

Kristen asks:
How long does the actual Gamma Knife procedure take?

Dr. Lee responds:
Generally, most patients arrive at 6am and the earliest patients are finished by 9:30am and the last patients are finished by noon. There is, of course, variability depending on the complexity of the procedure.

I am scheduled for Gamma Knife surgery next week. I read that I will be able to communicate with the surgical team. Will I also be able to see them, say through a closed-circuit TV?

Dr. Lee responds:
The physicians are able to see you and speak with you. The patient can speak to the physicians but cannot see them.

Mimi asks:
During Gamma Knife radiosurgery, how is the frame attached to the patient's head? Is it painful?

Dr. Lee responds:
Prior to placing the frame, patients are given medications through the IV to sedate them. For example, one of my patients recently immediately fell asleep right before the frame placement and could not remember the procedure at all.

Most patients remember some discomfort, but it is generally quite tolerable. In addition to the medication through the IV, I use lidocaine which is injected into the pin sites and is similar to the novacaine used by dentists.

For more information, watch this video to learn about how the Gamma Knife works.

JGator asks:
I've read that Gamma Knife surgery may cause headaches and nausea. Is this true? What is the recovery time? Is recovery time related to the number of tumors treated?

Dr. Lee responds:
Recovery time from the actual frame placement is usually one day. Late side effects from Gamma Knife usually arise approximately two to three months from the date of the radiosurgery. Symptoms are related to location and total dose, but the majority (90%) of patients experience no late side effects at all.

Shelley asks:
What is the difference between between Gamma Knife radiosurgery and stereotatic radiosurgery?

Dr. Lee responds:
Stereotactic radiosurgery refers to the delivery of a high dose of radiation in a specific three dimensional space in one session. Gamma Knife was the first device that was invented to perform stereotactic radiosurgery to the brain. Since the birth of Gamma Knife in the 1960s, many competitors have arisen, including Cyberknife, Novalis shaped-beam, etc. Gamma Knife is the only system that is completely dedicated to brain tumors and brain disorders.

Katrina asks:
Is Gamma Knife radiation better for hemangiopericytoma tumors than tomotherapy or other types of radiation? What are chances of acquiring radiation necrosis?

Dr. Lee responds:
Hemangiopericytoma can respond very well to Gamma Knife.  In fact, some of the most dramatic imaging responses are seen in patients with hemangiopericytoma.


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Gamma Knife and Leksell Gamma Knife are U.S. federally registered trademarks of Elekta Instrument S.A., Geneva, Switzerland. Photo credits: Susan Pardys, Elekta, Inc.

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