Brain Pet Scan

Positron Emission Tomograpghy (PET) is a diagnostic imaging tool that is a subset of nuclear medicine. A relatively recent medical innovation, PET technology was first created in the 1970s where it was used solely for medical research studies. Beginning in the early 1990s, PET imaging began to be used in a clinical setting where its unique abilities became an asset that made it possible for physicians to receive clear data about the body’s biochemical functioning, information that was previously gathered through exploratory surgery.

One of the greatest benefits of PET technology is its use in treating neurological disorders such as epilepsy, Alzheimer’s disease, and other dimentias. Additionally, PET scanning is able to produce images for a number of diseases that affect the brain such as post-traumatic brain injury, brain tumors, and movement disorders.

The brain PET scan is a safe imaging procedure that has a number of benefits over other forms of medical imaging. Anatomical imaging procedures like x-rays, computed tomography (CT), and magnetic resonance imaging (MRI) are useful tools that measure changes in body structure. However, they are limited in their use for a number of diseases, particularly in diseases that affect the brain. Positron Emission Technology, however, is a unique metabolic imaging tool that is based on molecular biology. The images that PET scanning is able to produce detail biochemical changes in the body’s tissues, as it traces the body’s metabolic activity, and is a useful tool for physicians who are attempting to pinpoint and evaluate diseases of the brain. In many instances, PET imaging is able to detect metabolic changes in the brain before anatomical or structural changes occur.

Still used in medical research, brain PET imaging is an exciting medical innovation that has a number of valuable clinical uses. Brain PET can help:

• Pinpoint and evaluate brain abnormalities and determine whether these abnormalities are caused by: Alzheimer’s disease, blood flow shortages, depression, or some other reason.
• Assist surgery for individuals with uncontrollable seizures by locally the brain site of seizure activity.
• Analyze muscle tremor and evaluate whether it this is caused by Parkinson’s disease or some other movement disorder.
• Evaluate brain tumors and determine whether they are benign (alive tissue and non-cancerous) or malignant (dead tissue and cancerous).
• Pinpoint the source of epileptic seizures.
• Assess such medical conditions as degenerative brain diseases, movement disorders, and dementias.
• Assist surgical operations by identifying the areas of the brain responsible for such critical functions as movement and speech.
• Analyze the effectiveness of chemotherapy by examining cites of possible cancer recurrence and distinguishing whether this structural change is due to tumor re-growth or is a form of scar tissue.

Brain PET imaging involves the administration of a radioactive tracer that is a combination of a radioisotope (a radioactive compound whose movements are detectable by a PET scanner) with a natural body compound. When used in brain scanning, the radioactive tracer used in PET is Fluorodeoxyglucose (FDG), which combines the natural body compound glucose with the radioisotope Fluorine-18. This radioactive tracer, or radiopharmaceutical, is used in brain PET imaging as the radioactive compound that it uses has a short half-life that will disappear from the body within hours. Although it is reasonable for individuals to be concerned about the radiation used in PET imaging, this procedure has been shown to be highly safe. Consequently, patients should free themselves of any worry about the radiation content of this procedure.

Brain PET scanning uses FDG as its radioactive tracer because it contains the body compound glucose. The use of FDG, which shares a similar structure to glucose, is important, as brain cells use glucose as their fuel. Consequently, through brain PET imaging, a physician will be able to easily identify brain activity. In cases where there is high brain activity, large amounts of FDG will be consumed. In instances where there is less active brain activity, there will be less absorption of FDG. By identifying brain activity, brain PET scan is useful in the treatment of a number of diseases affecting the brain.

The brain PET scan is a non-invasive diagnostic treatment that is highly safe with the most common complaint being boredom. No anesthesia is used so a patient is able to perform their regular activities following a brain PET scan. Additionally, the patient is awake throughout the whole procedure and the entire procedure is between 30 minutes and 2 hours.

The brain PET scan usually takes place in a major medical center that contains a small cyclotron, the machine that produces the radioisotopes used in the radioactive tracers. The patient arrives for their brain PET scan and lies on the scanning table. The patient is given special conditions to place against their head to hold their head in place throughout the PET screening process. The scanning table is attached to the PET scanner, a doughnut-shaped apparatus. The radioactive tracer, usually FDG, is then administered to the patient either through injection or inhalation. The radioactive tracer is used so the PET scanner is able to detect its movement. After the radioactive tracer is administered, the patient is taken to a partially darkened room where they rest quietly and wait for the radioactive tracer to be properly absorbed.

Once the radioactive tracer has been properly absorbed, the patient lies on the scanning table, which slowly moves through the opening in the scanner ring. Following the brain PET scan, the patient will learn of the results within three days.

Despite this simple and non-invasive procedure, there are some actions that a patient has to take prior to a brain PET scan. These include:

• Avoid eating and drinking for 4 hours prior to the appointment time. If the patient is diabetic they must not eat or drink 6 hours prior to the appointment time. Diabetics, however, are able to drink plenty of water prior to brain PET scan as well as eat a few saltine crackers if they begin to feel a drop in blood sugar levels.
• If taking medication, use only a sip of water to take it.
• For individuals undergoing a brain PET scan with electroencephalography (EEG, scalp electrical signal monitoring), the patient must first clean and dry their hair. Their hair should also be free of mousse or gel.
• Wear warm clothes and socks.