Definition
Positron emission tomography (PET) is an imaging test that uses a radioactive substance (called a tracer) to look for disease in the body. Unlike magnetic resonance imaging (MRI) and computed tomography (CT) scans, which reveal the structure of organs, a PET scan shows how the organs and tissues are functioning.

PET scans use a small amount of a radioactive substance injected into a vein, usually on the inside of the elbow. The substance travels through the blood and collects in organs or tissues.

The scan begins approximately 60 minutes after receiving the radioactive substance. The individual then lies on a table that slides into a tunnel-shaped hole in the center of the PET scanner.

The PET machine detects energy given off by the radioactive substance and converts it into 3-dimensional pictures. The images are sent to a computer, where they are displayed on a monitor for the physician to read.

The test takes about 30 minutes.

How to Prepare for the Test
You must sign a consent form before having this test. You will be told not to eat anything for 4 - 6 hours before the PET scan, although you will be able to drink water.

Tell your doctor if you are pregnant or think you might be pregnant.

Also tell your doctor about any prescription and over-the-counter medicines that you are taking, because they may interfere with the test.

Be sure to mention if you have any allergies, or if you've had any recent imaging studies using injected dye (contrast).

During the test, you may need to wear a hospital gown. Take off any jewelry, dentures, and other metal objects because they could affect the scan results.

Why the Test is Performed
A PET scan can reveal the size, shape, position, and function of the brain and other organs.  It is used to diagnose cancer, heart problems, and brain disorders. It can see how far cancer has spread, reveal areas of poor blood flow to the heart, and check brain function.

Normal Results
A normal scan reveals no problems in the size, shape, or position of an organ. An abnormal scan reveals areas in which the radiotracer has abnormally collected.

Risks
The amount of radiation used in a PET scan is low. It is about the same amount of radiation as in most CT scans. Also, the radiation doesn't last for very long in your body.

However, women who are pregnant or are breastfeeding should let their doctor know before having this test. Infants and fetuses are more sensitive to the effects of radiation because their organs are still growing.

It is possible, although very unlikely, to have an allergic reaction to the radioactive tracer. Some people have pain, redness, or swelling at the injection site.




 

Read the full article here.

 Brain Imaging: Understanding the Basics

 Frequently Asked Questions

 1 – What is brain imaging?

 Brain imaging allows scientists and doctors to view and monitor the areas of the brain. Brain images can be produced using structural imaging techniques, commonly MRI (Magnetic Resonance Imaging) and CAT (Computed Axial Tomography), or functional imaging strategies like PET (Positron Emission Tomography) and functional MRI (fMRI). Structural imaging is designed to identify abnormalities such as strokes, bleeding, and tumors, while functional imaging procedures evaluate how the brain is working. Functional imaging techniques can be used to study the brain at rest, or during an activity such as when a person is hearing, seeing, feeling, moving, talking and thinking. These measurements are based on the flow of blood in the brain, and changing levels of oxygen in specific brain regions depending on that flow.

 2 – How is brain imaging used for understanding brain injury?

 In addition to studying the anatomy or structure of injury, studies during the past few years have shown that fMRI and PET scans may be able to capture an image of activity in the brain of an injured patient that is not possible to know or see otherwise. This is particularly important as some brain injuries result in loss of speech and movement.

During a scan, the patient may be asked to listen to familiar voices, or to imagine themselves in different scenes like being at home or playing tennis.

 Learning about the parts of the brain that are activated in such cases may help scientists and doctors have a better understanding of disorders of consciousness that can occur after brain injury, such as the vegetative and minimally conscious states. Repeated brain scans over time may help scientists and doctors better understand the process of recovery and the effectiveness of different rehabilitation techniques.

 3 – Can brain imaging be used to determine whether someone is conscious?

 At present, there are no diagnostic tests capable of detecting whether someone is conscious. Conversely, there are no imaging tests that can determine if someone is unconscious. Specialized rating scales and brain imaging techniques have been developed to investigate the likelihood that someone is consciously processing information, but neither of these approaches provides definitive evidence of consciousness or unconsciousness. Despite their limitations, doctors currently rely on bedside examination findings to diagnose disorders of consciousness.

 4 – What have we learned so far?

 In the few studies conducted to date, scientists have found that patterns of brain activation in patients in minimally conscious states can look similar to those of non-injured people when responding to language and other types of stimulation. In the future, the results of these studies may help improve diagnostic and prognostic accuracy.

 5 – Should I enroll my family member in a brain imaging study?

You should find out what is involved with a brain imaging study before acting as the decision-maker to enroll someone, such as your family member, by talking to your doctor and the scientist requesting your consent. Most studies pose minimal risk to the patient and the participation of your loved one can add important knowledge to the understanding of disorders of consciousness. It is critical to stress that, at the present time, these studies are entirely experimental. Therefore, you cannot expect to learn new information about the person’s condition, or to use the information in decision-making about next steps for his or her care.

 6 – What should I expect of future research?

 As new knowledge is gained every day about how the brain works, you can expect ever-improving diagnosis of and treatment for brain injury. The choice to participate in research is yours or another designate on behalf of another individual. Make the choice based by thinking about whether the person would have volunteered. Carefully assess the desire to contribute to science, the acceptability of participation to your family and others important to the person in question, and have a clear appreciation that whatever is learned from the study will have limited, if any benefit for you or your family member.

Written by:

Dr. Judy Illes and Patricia Lau, The University of British Columbia, Vancouver, British Columbia

Dr. Joseph T. Giacino, JFK Johnson Rehabilitation Institute, New Jersey

Acknowledgements:

The Greenwall Foundation, Dr. Joseph J. Fins (Weill Cornell Medical College), Dr. Emily Murphy (Stanford University), and members of the Ethics, Neuroimaging, and Limited States of Consciousness Workshop, Stanford University June 2007.

©2008 The University of British Columbia

In my practice I see neurologists hired by worker's compensation and insurance companies citing the "normal" results of MRI in mild and moderate brain injury cases in their effort to show the patient is faking injury.  While this is statistically consistent - that normal MRI is found in mild and moderate cases - the use of Tesla 3 MRI digs deeper, so to speak, to reveal the microscopic changes in the brain.  This helps not only the lawyer trying to prove a case, but the medical provider in diagnosing and treating a patient.

I found this recent article supporting Tesla 3 MRI. "Reports outline magnetic resonance imaging study results from University of Bonn." Science Letter. NewsRX. 2009. HighBeam Research. 21 Oct. 2009 <http://www.highbeam.com>.

In this recent report published in the Journal of Magnetic Resonance Imaging, researchers in Bonn, Germany conducted a study "To evaluate the feasibility of automatic planning and scanning of brain MR imaging (MRI) protocols on a clinical 3 Tesla system in tumor patients before and after neurosurgical intervention. Twenty-nine patients with intra-axial lesions were examined with automated planscan software pre- and postoperatively."

The researchers concluded: "These results are promising to minimize interscan variability in longitudinal studies."

 The study, published in the September 9, 2009, issue of the Journal of the American Medical Association, also has important implications for treatment. "Finding ways to address the underlying reward-system deficit could improve the direct clinical outcome of ADHD, and potentially reduce the likelihood of other negative consequences of this condition," said study co-author Gene-Jack Wang, chair of Brookhaven's medical department.

PET scans are commonly used to investigate the following conditions:
Epilepsy - it can reveal which part of the patient's brain is being affected by epilepsy. This helps doctors decide on the most suitable treatments.MRI and/or CT scans are recommended for people after a first seizure, this study explains.

Alzheimer's disease - it is very useful in helping the doctor diagnose Alzheimer's disease. A PET scan that measures uptake of sugar in the brain significantly improves the accuracy of diagnosing a type of dementia often mistaken for Alzheimer's disease, a study revealed.

Interesting related articles:

What is MRI? How does MRI work?

What is a CT scan? What is a CAT scan?
Cancer - PET scans can show up a cancer, reveal the stage of the cancer, show whether the cancer has spread, help doctors decide on the most appropriate cancer treatment, and give doctors an indication on the effectiveness of ongoing chemotherapy. A PET scan several weeks after starting radiation treatment for lung cancer can indicate whether the tumor will respond to the treatment, a study showed. This article looks at whether PET scans are beneficial during cancer diagnosis, staging and monitoring.

Heart disease - a PET scan helps detect which specific parts of the heart have been damaged or scarred. Any faults in the working of the heart are more likely to be revealed with the help of a PET scan. A study revealed how comprehensive diagnosis of heart disease based on a single CT scan is possible.

Medical research - researchers, especially those involved in how the brain functions get a great deal of vital data from PET scans.

Here is the latest Columbia Encyclopedia definition available for Title: PET scan

Date: 4/24/2008; Publication: The Columbia Encyclopedia, Sixth Edition;

PET scan or positron emission tomography , a medical imaging technique that monitors metabolic, or biochemical, activity in the brain and other organs by tracking the movement and concentration of a radioactive tracer injected into the bloodstream. The technique uses special computerized imaging equipment and rings of detectors surrounding the patient to record gamma radiation produced when positrons (positively charged particles) emitted by the tracer collide with electrons.

PET scans are especially valuable in imaging the brain. They are used in medicine to diagnose brain tumors and strokes, and to locate the origins of epileptic activity; in psychiatry to examine brain function in schizophrenia , bipolar disorder , and other mental illnesses; and in neuropsychology to study such brain functions and capabilities as speech, reading, memory, and dreaming.

Author not available, PET SCAN., The Columbia Encyclopedia, Sixth Edition 2008
The Columbia Encyclopedia, Sixth Edition. Copyright 2008 Columbia University Press
 

This information was derived from Microsoft® Encarta® Online Encyclopedia 2007:

Brain Imaging

Magnetic Resonance Imaging or MRI

Magnetic resonance imaging (MRI), introduced in the early 1980s, beams high-frequency radio waves into the brain in a highly magnetized field that causes the protons that form the nuclei of hydrogen atoms in the brain to reemit the radio waves. The reemitted radio waves are analyzed by computer to create thin cross-sectional images of the brain. MRI provides the most detailed images of the brain and is safer than imaging methods that use X rays. However, MRI is a lengthy process and also cannot be used with people who have pacemakers or metal implants, both of which are adversely affected by the magnetic field.

Computed Tomography or CT

Computed tomography, also known as CT scans, developed in the early 1970s. This imaging method X-rays the brain from many different angles, feeding the information into a computer that produces a series of cross-sectional images. CT is particularly useful for diagnosing blood clots and brain tumors. It is a much quicker process than magnetic resonance imaging and is therefore advantageous in certain situations—for example, with people who are extremely ill.

Functional Magnetic Resonance Imaging of fMRI

Changes in brain function due to brain disorders can be visualized in several ways. Magnetic resonance spectroscopy measures the concentration of specific chemical compounds in the brain that may change during specific behaviors. Functional magnetic resonance imaging (fMRI) maps changes in oxygen concentration that correspond to nerve cell activity.

Positron Emission Tomography or PET

Positron emission tomography (PET), developed in the mid-1970s, uses computed tomography to visualize radioactive tracers (see Isotopic Tracer), radioactive substances introduced into the brain intravenously or by inhalation. PET can measure such brain functions as cerebral metabolism, blood flow and volume, oxygen use, and the formation of neurotransmitters. Single photon emission computed tomography (SPECT), developed in the 1950s and 1960s, uses radioactive tracers to visualize the circulation and volume of blood in the brain.

There is certainly an argument that doctors have been placed in the unenviable position of having to protect themselves by practicing "defensive medicine."  But more compelling is the information neuroimaging provides in saving lives or prescribing proper care.

It is no wonder that diagnostic tests increase as technology increases.  Moreover, doctors' ability to see and treat disease increases with the use of neuroimaging technology.  Just as the Hubbell telescope  allows us to see things in outer space previously unseen and allows us to create theories of Relativity, we are better informed and able to understand that sun does not evolve around earth but earth around sun.

Fortunately health insurance companies do not dispute such theories and facts - but if they could save money doing it I bet they would!

Read the article in today's Newsday.

To read more click Study by Center for Studying Health System Change http://hschange.org/CONTENT/968/

60 Minutes

The story describes fireman Don Herbert who was injured when a roof fell on him while making a rescue attempt.  Unconscious for 10 years, Don is shown waking up and being aware of the fact that he was "gone."

The next story is of George Menendez who also sustained brain injury and was minimally conscious.  His mother thought to give him Ambien for sleep one night when he was moaning.  George, for the first time, opened his eyes and was able to communicate with his family.

Experts believe there is a subset of brain injured people who may respond to Ambien.  PET scans were done before and after Ambien was ingested and the results were remarkable.  The brain showed distinctive functioning after Ambien.

This is an exciting discovery and I hope there is more to come.  To see the amazing 12 minute video click here.