Glossary of Terms

AVM (arteriovenous malformation) - an abnormal, congenital tangle of blood vessels in the brain that is prone to bleeding. This bleeding can cause symptoms ranging from headaches and seizures to neurologic catastrophes and even death.

benign - not cancerous, not malignant.

chemotherapy - a treatment that destroys tumor cells through the use of chemicals injected into the body or taken orally over a period of time.

"conformal" radiosurgery - shapes the radiation beam to fit the tumor or malformation perfectly, rather than using the traditional method of multiple circular beams. Conformal radiosurgery maximizes radiation to the tumor or malformation and minimizes doses to surrounding healthy tissue.

CNS (central nervous system) - the brain and spinal cord.

CT (computerized tomography) - a diagnostic imaging technique in which an x-ray machine and computer are used to create a detailed picture of the body's tissues and structures. A dye, or contrast agent, may be injected into the patient to highlight abnormalities in tissue.

critical structures - areas in the brain that are responsible for such vital functions as memory, speech, hearing, sight and movement.

EEG (electroencephalogram) - a diagnostic procedure in which special pieces of material are placed on the scalp or fine needles are placed in the brain to record electrical activity in the brain.

glioma -arising from the supportive tissue of the brain, they are the most common primary brain tumors. Astrocytomas, ependymomas, oligodendrogliomas and tumors with mixtures of two or more of these cell types are the most common gliomas.

Image Guided Surgery (IGS) - provides the neurosurgeon with the ability during surgery to see the brain in three dimensions and to accurately pinpoint a location in the brain or spinal cord with the aid of computed tomography (CT) and magnetic resonance (MR).

inaccessible tumor - a tumor that cannot be removed surgically because its location creates a high risk of damage to the nervous system or vital areas of the brain.

lumbar puncture (also known as a spinal tap) - a procedure used to withdraw a small sample of cerebrospinal fluid, which can then be examined for abnormal cells.

malignant - cancerous.

meningioma - a brain tumor that grows in the meninges, a thin layer of tissue covering the brain and spinal cord.

metastatic tumor - a tumor caused by cancer cells that originate elsewhere in the body and travel to the current site through the blood stream.

MRI (magnetic resonance imaging) - an imaging technique that uses a magnetic field and radio waves (rather than x-rays) to distinguish between healthy and diseased tissues.

PET (positron emission tomography) - an imaging technique that provides a picture of brain activity by measuring levels of injected glucose sugar "labeled" with a radioactive marker.

primary brain tumor - a tumor that originates in the brain.

primitive neuroectodermal tumors - also known as neuroblastomas, they usually affect children, adolescents or young adults. Scientists believe these tumors arise from primitive cells that remain after early development of the brain and spinal cord.

radiosurgery - a treatment that attacks a tumor with beams of radiation.

stereotactic radiosurgery- radiation therapy that precisely locates the tumor through use of a three-dimensional frame of reference.