Protocol Number: 02-N-0181
Healthy normal volunteers and patients with Tourette's syndrome between 21 and 65 years of age may be eligible for this study. Candidates will be screened with a medical history and physical and neurological examinations. Participants will undergo positron emission tomography (PET) scanning to measure brain blood flow. For this procedure, the subject receives an injection of H215O, a radioactive substance similar to water. A special camera detects the radiation emitted by the H215O, allowing measurement of the blood flow. Subjects will receive up to five injections of H215O during the scanning. They will also be injected with another radioactive chemical, (11C) flumazenil, which binds to GABA receptors, to measure the density and distribution of these receptors. This will reveal which areas of the brain in patients with Tourette's syndrome have abnormal binding of flumazenil compared with the brains of healthy control subjects. During the PET procedure, the subject lies on a table in the PET scanner. A small catheter (plastic tube) is placed in an arm vein for injecting the radioactive tracers, and a mask is placed on the face to help keep the head still during scanning. The mask has large openings for eyes, nose and mouth, so that it does not interfere with talking or breathing. The entire test takes about 3 hours. On a separate day, participants will also undergo magnetic resonance imaging (MRI), a diagnostic test that uses a magnetic field and radio waves to produce images of the brain. For this procedure, the subject lies still on a stretcher that is moved into the scanner (a narrow cylinder containing the magnet). Earplugs are worn to muffle loud noises caused by electrical switching of radio frequency circuits used in the scanning process. The scan lasts about 45 to 60 minutes.
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National Institutes of Health Clinical Center
Bethesda, Maryland 20892. Last update: 01/30/2009
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