What conditions are treated with Gamma Knife?

While Gamma Knife is most commonly used to treat both malignant and benign brain tumors as well as small arteriovenous malformations (AVMs) and lesions, a growing number of patients with other disorders have experienced positive results with Gamma Knife treatment. The treatment may also be useful as an adjunct therapy for patients with recurrent tumors after radiation treatment.

Experts at Memphis Regional Gamma Knife Center, working with referring physicians, have successfully treated the following conditions:


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Gamma Knife is used to treat arteriovenous malformations

According to the National Institute of Neurological Disorders and Stroke, arteriovenous malformations (AVMs) are defects of the circulatory system that are generally believed to arise during embryonic or fetal development or soon after birth. Although AVMs can develop in different sites, those located in the brain or spinal cord can have especially widespread effects on the body. Most people with neurological AVMs experience few, if any, significant symptoms. For about 12 percent of the affected population (about 36,000 of the estimated 300,000 Americans with AVMs), these abnormalities cause symptoms that vary greatly in severity. Seizures and headaches are the most generalized symptoms. AVMs also can cause a wide range of more specific neurological symptoms that vary depending primarily upon the location of the AVM. Such symptoms may include muscle weakness or paralysis, loss of coordination, difficulties carrying out tasks that require planning, dizziness, visual disturbances, problems using or understanding language, abnormal sensations (such as numbness, tingling or spontaneous pain), memory deficits, mental confusion, hallucinations, or dementia.

For more information on AVMs, visit the National Institute of Neurological Disorders and Stroke web site.


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Gamma Knife is used to treat benign brain tumors

According to the National Institute of Neurological Disorders and Stroke, brain tumors are abnormal growths of tissue found inside the skull, which are the primary components of the central nervous system (CNS). Benign tumors are noncancerous and do not spread to other parts of the body. The CNS is housed within rigid, bony quarters (i.e., the skull and spinal column), so any abnormal growth, whether benign or malignant, can place pressure on sensitive tissues and impair function. Tumors that originate in the brain are called primary tumors. Most primary tumors are caused by out-of-control growth among cells that surround and support neurons. In a small number of individuals, primary tumors may result from specific genetic disease (e.g., neurofibromatosis, tuberous sclerosis) or from exposure to radiation or cancer-causing chemicals. The cause of most primary tumors remains a mystery. They are not contagious and, at this time, not preventable. Symptoms of brain tumors include:

For more information on brain tumors, visit the National Institute of Neurological Disorders and Stroke.


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Gamma Knife is used to treat pituitary adenomas

According to the U.S. National Library of Medicine, a pituitary adenoma is an abnormal growth, or tumor, in the pituitary gland, the part of the brain that regulates the body's balance of hormones. Pituitary adenomas are benign, but can lead to nerve damage, growth disturbances and changes in hormonal balance. While the cause is unknown, some pituitary tumors have been associated with mutations in DNA.

Symptoms of pituitary adenomas can vary considerably, largely depending on whether or not the tumor is secreting one or more of a variety of hormones. Even if the tumor is not producing any hormones, its location at the base of the brain can cause significant symptoms, including:

For more information on pituitary adenomas, visit the U.S. National Library of Medicine web site.


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Gamma Knife is used to treat Craniopharyngiomas

According to the Pituitary Network Association, craniopharyngiomas are intracranial tumors that are typically both cystic and solid in structure. They occur most commonly in childhood and adolescence and in later adult life after age 50 years, and account for two to four percent of primary brain tumors. Craniopharyngiomas are usually not discovered until they press on important surrounding structures, and are frequently quite large (over three cenimeters) when detected. They are histologically benign tumors, but they have a tendency to become adherent to structures in and around the pituitary gland and pituitary stalk, including the optic nerves, optic chiasm, intracranial arteries and the brain itself. They are thought to arise from remnants of the craniopharyngeal duct or Rathkes pouch, which are developmental structures related to the primitive gut. Embryonic cells from an incomplete involuted craniopharyngeal duct or anterior pituitary gland may give rise to a craniopharyngioma.

The symptoms produced by a craniopharyngioma vary depending upon the tumor's location. If it compresses the pituitary stalk or involves the area of the pituitary gland itself, the tumor can cause partial or complete pituitary hormone deficiency. This frequently results in one or more of the following:

Pituitary stalk compression can also cause diabetes insipidus and may increase prolactin levels causing a milky discharge from the breast (galactorrhea). If the craniopharyngioma involves the optic tracts, chiasm or nerves, then visual disturbances can result. Involvement of the hypothalamus, an area at the base of the brain, may result in obesity, increased drowsiness, temperature regulation abnormalities and diabetes insipidus. Other common symptoms include personality changes, headache, confusion and vomiting.

For more information on craniopharyngiomas, visit the Pituitary Network Association.


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Gamma Knife is used to treat metastatic brain lesions

According to the National Brain Tumor Foundation, a metastatic brain tumor is one that begins as cancer in another part of the body. Some of the cancer cells may be carried to the brain by the blood or lymphatic fluid, or may spread from adjacent tissue. The site where the cancerous cells originated is referred to as the primary cancer. Metastatic brain tumors are often referred to as lesions or brain metastases and are the most common brain tumors. There has been an increase in metastatic lesions as people are surviving primary cancers for longer periods of time.

Characteristics:

Symptoms:


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Gamma Knife is used to treat Trigeminal Neuralgia

According to the National Institute of Neurological Disorders and Stroke, trigeminal neuralgia (TN), also called tic douloureux, is a chronic pain condition that causes extreme, sporadic, sudden burning or shock-like face pain. TN pain is typically felt on one side of the jaw or cheek and can be physically and mentally incapacitating. The pain seldom lasts more than a minute or two per episode. Episodes can last for days, weeks or months at a time and then disappear for months or years. In the days before an episode begins, some patients may experience a tingling or numbing sensation or a constant aching pain. The attacks often worsen over time, with fewer and shorter pain-free periods before they recur. The intense flashes of pain can be triggered by vibration or contact with the cheek (such as shaving, washing the face or applying makeup), brushing teeth, eating, drinking, talking or being exposed to the wind. TN occurs most often in people over age 50 and is more common in women than in men. Although sometimes debilitating, the disorder is not life-threatening.

The presumed cause of TN is a blood vessel pressing on the trigeminal nerve in the head as it exits the brainstem. TN may be part of the normal aging process but in some cases it is the associated with other disorders, such as multiple sclerosis or other disorders characterized by damage to the myelin sheath that covers certain nerves.

For more information on TN, visit the National Institute of Neurological Disorders and Stroke.


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Gamma Knife is used to treat Cushing's Disease

According to the National Endocrine and Metabolic Diseases, Cushing's Disease occurs when the body's tissues are exposed to excessive levels of cortisol for long periods of time. Many people suffer the symptoms of Cushing's Disease because they take glucocorticoid hormones such as prednisone for asthma, rheumatoid arthritis, lupus and other inflammatory diseases, or for immunosuppression after transplantation.

Others develop Cushing's Disease because of overproduction of cortisol by the body. Normally, the production of cortisol follows a precise chain of events. First, the hypothalamus, a part of the brain, which is about the size of a small sugar cube, sends corticotropin releasing hormone (CRH) to the pituitary gland. CRH causes the pituitary to secrete ACTH (adrenocorticotropin), a hormone that stimulates the adrenal glands. When the adrenals, which are located just above the kidneys, receive the ACTH, they respond by releasing cortisol into the bloodstream.

Cortisol performs vital tasks in the body. It helps maintain blood pressure and cardiovascular function, reduces the immune system's inflammatory response, balances the effects of insulin in breaking down sugar for energy and regulates the metabolism of proteins, carbohydrates and fats. One of cortisol's most important jobs is to help the body respond to stress. Women in their last three months of pregnancy and highly trained athletes normally have high levels of the hormone. People suffering from depression, alcoholism, malnutrition and panic disorders also have increased cortisol levels.

When the amount of cortisol in the blood is adequate, the hypothalamus and pituitary release less CRH and ACTH. This ensures that the amount of cortisol released by the adrenal glands is precisely balanced to meet the body's daily needs. However, if something goes wrong with the adrenals or their regulating switches in the pituitary gland or the hypothalamus, cortisol production can go awry.

For more information on Cushing's Disease, visit the National Endocrine and Metabolic Diseases' web site.


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Gamma Knife is used to treat selective gliomas

According to the Society for Neuroscience, most brain tumors develop from cancerous glial cells and are called gliomas. Unlike other cancers, glioma tumors grow in the confined space inside the head. In order to grow, most cancers push healthy cells aside, but due to space constraints, glioma tumors must destroy normal brain cells. To kill healthy nerve cells, glioma tumors release large quantities of the neurotransmitter glutamate. Excess glutamate is toxic to neurons and causes seizures in up to 80 percent of people with gliomas. Depending on the tumor's size and location, other symptoms include paralysis, behavior changes and dizziness.