Stereotactic radiosurgery





Definition

Stereotactic radiosurgery is the use of a precise beam of radiation to destroy tissue in the brain.


Purpose

This procedure is used to treat brain tumors, arteriovenous malformations in the brain, and in some cases, benign eye tumors or other disorders within the brain.


Demographics

Stereotactic radiosurgery is used to treat a variety of disorders with widely differing demographic profiles.


Description

"Radiosurgery" refers to the use of a high-energy beam of radiation. "Stereotactic" refers to the three-dimensional targeting system used to deliver the beam to the precise location desired. Stereotactic radiosurgery is primarily confined to the head and neck, because the patient must be kept completely still during the delivery of the radiation in order to prevent damage to surrounding tissue. The motion of the patient's head and neck are restricted by a stereotactic frame that holds them in place. It is difficult to immobilize other body regions in this way.

The high energy of the radiation beam disrupts the DNA of the targeted cells, killing them. Multiple weak beams are focused on the target area, delivering maximum energy to it while keeping surrounding tissue safe. Since the radiation passes through the skull to its target, there is no need to cut open the skull to perform the surgery. The beam can be focused on any structure in the brain, allowing access to tumors or malformed blood vessels that cannot be reached by open-skull surgery.

Two major forms of stereotactic radiosurgery are in use as of 2003. The Gamma Knife ® is a stationary machine that is most useful for small tumors, blood vessels, or similar targets. Because it does not move, it can deliver a small, highly localized and precise beam of radiation. Gamma knife treatment is done all at once in a single hospital stay. The second type of radiosurgery uses a movable linear accelerator-based machine that is preferred for larger tumors. This treatment is delivered in several small doses given over several weeks. Radiosurgery that is performed with divided doses is known as fractionated radiosurgery. The total dose of radiation is higher with a linear accelerator-based machine than with gamma knife treatment.

Disorders treated by stereotactic radiosurgery include:

  • benign brain tumors, including acoustic neuromas and meningiomas
  • malignant brain tumors, including gliomas and astrocytomas
  • metastatic brain tumors
  • trigeminal neuralgia
  • Parkinson's disease
  • essential tremor
  • arteriovenous malformations
  • pituitary tumors

Diagnosis/Preparation

A patient requiring radiosurgery has already been diagnosed with a specific disorder that affects the brain. As preparation for radiosurgery, he or she will undergo neuroimaging studies to determine the precise location of the target area in the brain. These studies may include CT scans , MRI scans, and others. Imaging of the blood vessels ( angiography ) or the brain's ventricles (ventriculography) may be done as well. These require the injection of either a harmless radioactive substance or a contrast dye.

Prior to the procedure, the patient will be fitted with a stereotactic frame or rigid mask to immobilize the head. This part of the treatment may be uncomfortable. The patient may receive a simulation scan to establish the precise relationship of the mask or frame to the head to help plan the treatment.

The patient may be given a sedative and an antinausea agent prior to the simulation scan or treatment.


Aftercare

Stereotactic radiosurgery does not produce some of the side effects commonly associated with radiation treatment, such as reddening of the skin or hair loss. Most patients can return to their usual daily activities following treatment without any special precautions.


Risks

The risks of stereotactic radiosurgery include mild headache, tiredness, nausea and vomiting, and recurrence of the tumor. Questions have been raised as to whether radiosurgery can cause secondary tumors, but as of 2003, there is little detailed information about this potential risk.


Normal results

Stereotactic radiosurgery does not cause pain; and because the skull is not opened, there is no long hospital stay or risk of infection. Recovery is very rapid; most patients go home the same day they are treated, although follow-up imaging and retreatment may be necessary in some cases. This form of surgery appears to be quite successful in extending the length of survival in cancer patients; one study found that gamma knife radiosurgery controlled tumor growth in 96% of patients with kidney cancer that had spread to the brain, and added an average of 15 months to the patients' survival.

Morbidity and mortality rates

Stereotactic radiosurgery has a low reported rate of serious complications with minimal mortality. One German study reported a 4.8% rate of temporary morbidity in patients under treatment for brain tumors, with no permanent morbidity and no mortality. An American group of researchers found that less than 2% of patients who had eye tumors treated with radiosurgery suffered damage to the optic nerve from the dose of radiation.

Mild side effects following gamma knife radiosurgery are not uncommon, however. One group of British researchers found that 47 out of a group of 65 patients treated with gamma knife surgery had mild or moderate side effects within two weeks of treatment. Of these patients, more than half suffered headaches and a fifth reported unusual tiredness or nausea and vomiting.


Alternatives

With certain types of brain tumors, whole-brain radiation treatment (WBRT) is an option; however, it has a number of severe side effects. Surgical removal of the tumor is another option, but it carries a higher risk of tumor recurrence. For other tumors, gamma knife radiosurgery is the only treatment available as of 2003.


Resources

BOOKS

"Acoustic Neuroma." Section 7, Chapter 85 in The Merck Manual of Diagnosis and Therapy , edited by Mark H. Beers, MD, and Robert Berkow, MD. Whitehouse Station, NJ: Merck Research Laboratories, 1999.

"Radiation Injury of the Nervous System." Section 14, Chapter 177 in The Merck Manual of Diagnosis and Therapy , edited by Mark H. Beers, MD, and Robert Berkow, MD. Whitehouse Station, NJ: Merck Research Laboratories, 1999.


PERIODICALS

Chua, D. T., J. S. Sham, P. W. Kwong, et al. "Linear Accelerator-Based Stereotactic Radiosurgery for Limited, Locally Persistent, and Recurrent Nasopharyngeal Carcinoma; Efficacy and Complications." International Journal of Radiation Oncology, Biology, Physics 56 (May 1, 2003): 177-183.

Ganz, J. C. "Gamma Knife Radiosurgery and Its Possible Relationship to Malignancy: A Review." Journal of Neurosurgery 97 (December 2002) (5 Suppl): 644-652.

Muacevic, A., and F. W. Kreth. "Significance of Stereotactic Biopsy for the Management of WHO Grade II Supratentorial Glioma." [in German] Der Nervenarzt 74 (April 2003): 350-354.

O'Neill, B. P., N. J. Iturria, M. J. Link, et al. "A Comparison of Surgical Resection and Stereotactic Radiosurgery in the Treatment of Solitary Brain Metastases." International Journal of Radiation Oncology, Biology, Physics 55 (April 1, 2003): 1169-1176.

St. George, E. J., J. Kudhail, J. Perks, and P. N. Plowman. "Acute Symptoms After Gamma Knife Radiosurgery." Journal of Neurosurgery 97 (December 2002) (5 Suppl): 631-634.

Sheehan, J. P., M. H. Sun, D. Kondziolka, et al. "Radiosurgery in Patients with Renal Cell Carcinoma Metastasis to the Brain: Long-Term Outcomes and Prognostic Factors Influencing Survival and Local Tumor Control." Journal of Neurosurgery 98 (February 2003): 342-349.

Stafford, S. L., B. E. Pollock, J. A. Leavitt, et al. "A Study on the Radiation Tolerance of the Optic Nerve and Chiasm After Stereotactic Radiosurgery." International Journal of Radiation Oncology, Biology, Physics 55 (April 1, 2003): 1177-1181.


ORGANIZATIONS

International Radiosurgery Support Association (IRSA). 3005 Hoffman Street, Harrisburg, PA 17110. (717) 260-9808. http://www.irsa.org .

Johns Hopkins Radiosurgery. Weinberg 1469, 600 North Wolfe Street, Baltimore, MD 21287. (410) 614-2886. <www.hopkinsmedicine.org/radiosurgery/treatmentoptions/stereotact cradiosurgery.cfm> .


Richard Robinson

WHO PERFORMS THE PROCEDURE AND WHERE IS IT PERFORMED?



Stereotactic radiosurgery is performed by a radiosurgeon, who is a neurosurgeon with advanced training in the use of a gamma knife or linear accelerator-based machine. The radiosurgeon's dose plan is checked by a physicist before the treatment is administered to the patient. Stereotactic radiosurgery is done in a hospital that has the necessary specialized equipment.

QUESTIONS TO ASK THE DOCTOR



  • What are the alternatives, if any, to radiosurgery for my specific condition?
  • How many radiosurgical procedures have you performed?
  • What is your success rate?
  • What side effects have your patients reported?

User Contributions:

Walter Morse
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Apr 5, 2007 @ 5:17 pm
My wife of 30 yrs is going thru being diagnosed with a brain tumor which the dr is yet to confirm as the mri path is still not in his hands.However, ct scans, mri's & her general syptoms indicate he is right.He has her scheduled for a procedure on wednes next.We pray for her & hope to God she pulls thru this problem.She is only 59.
Tom Gregory
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Dec 4, 2007 @ 2:14 pm
Do you know of any patients reporting pancreatic adenocarcinoma within 2 months of having GK surgery? Thank you.

Sincerely,

Tom Gregory
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Jun 13, 2011 @ 1:13 pm
I am waiting for Gamma Knife surgery at the moment, does any one know if you are aloud to fly after treatment,also im worried about what it involves.
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Jun 24, 2011 @ 3:03 am
Is there a chance that the tumor won't grow back again even if it's malignant when targeted woth the gamma knife?
Shirley Lain
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Aug 25, 2012 @ 10:22 pm
I went in an airplane 6 months after my gamma knife and it caused excellerated issues like dizzyness, balancing was more difficult and 3 mohts after that facial palseys began to happen daily. I am looking at undergoing a full tumor removal. I wish they had told me not to fly
Tara
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Aug 26, 2012 @ 5:17 pm
I'm a 51 year old woman and have been suffering mieblasry with the intolerable pain symptoms of Trigeminal Neuralgia in my lower right jaw. I also have a Perotid mass growing in front of my right ear. After having root canals in nearly all of my teeth, a molar extraction, a bite plate made for the potential of TMJ none of which provided any relief, my dentist finally recommended I see an Endodontist who referred me to an ENT and/or Neurologist. I just saw an ENT who ordered a CT Scan, is the one who identified the very obvious Parotid tumor and told me it must be removed. He claims he has performed more than 400 of this type of surgery But my concern is that he did NOT acknowledge the association with my Trigeminal Neurology symptoms nor whether the removal of the tumor would relieve my pain. Is it that he wouldn't know until he sees the results of the CT scan or actually got inside and was able to identify if the tumor was the cause, OR should I be concerned that he isn't the right kind of doctor for my particular case?? I've lost a lot of weight (which I can't afford to lose I'm 5'4 and down to 105 lbs) because I'm terrified of the pain when I eat, I can barely get through brushing my teeth or washing my face, and sometimes am unable to finish a sentence without having an attack. BUT, here's a strange twist that I've never heard of with either of these two conditions : Sometimes certain foods will trigger an attack on contact in my mouth BEFORE I even chew. Could this be a saliva gland reaction/trigger since they all somehow seem to be related? This is the one symptom that appears to be unique to my situation. It's difficult to find reliable facts from cases I've read about on the Internet, so I'm frustrated, scared, angry, depressed and to make matters worse or shall I say seemingly hopeless, I do not have health or dental insurance. Where does one turn under these circumstances and hope to get the best care necessary?
Rocio
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Jan 20, 2013 @ 10:10 am
six years ago I underwent Gamma knife Radio Surgery my question is after this procedure
Is how long before I can travel by plane if It is possible?

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