What is PET?
Positron Emission Tomography (PET) produces images of molecular-level physiological functioning, which can help physician identify normal and abnormal states. As in traditional nuclear medicine, PET uses radiopharmceuticals or "tracers," which are labeled with isotopes such as carbon, oxygen, nitrogen and fluorine. These isotopes mimic sugars, water, proteins and oxygen. As a result, PET can often reveal more about the cellular-level metabolic status of a disease than the CT or MR. PET can help diagnose a disease often before it shows up on other tests. PET can also show the progress of a disease as well as how the body is responding to treatment.
Current Applications
The three areas in which PET is making critical contributions are:
How PET Works
PET procedures may vary, but in general, a PET technologist administers the radioisotope by injection to the patient, who lies still for about 45 minutes, and then is scanned for approximately one hour.
Will my insurance cover PET?
Many insurance companies are reimbursing for PET procedures. Medicare has approved the following exams: lung cancer, recurrent colorectal, melanoma and lymphoma. Contact your insurer directly to learn about payment reimbursement.
Discover the power of Positron Emission Tomography (PET). When your doctor refers you for a PET scan, you will be introduced to a medical imaging technique that can search for cancer anywhere in your body, can diagnose Alzheimer's disease years before symptoms occur or prove that bypass surgery would benefit your damaged heart. PET can tell you whether a tumor is benign or malignant and can show you if a malignant tumor has spread. Search our website and learn how PET is changing the way doctors manage your care for some of today's most devastating medical conditions.
What is PET used to diagnose?
PET is used to diagnose and stage patients with cancer, as well as patients with certain brain and heart disorders.
In cancer, PET can:
In the brain, PET can:
In the heart, PET can:
Your Physician has ordered a Positron Emission Tomography (PET) scan for you. PET images can provide important information about many conditions affecting the heart, brain, and other organs, which will help your doctor plan appropriate treatment for you.
PET images are different than those from more conventional imaging equipment, such as x-ray, CT, Ultrasound, or MRI. These images show what the tissues look like. PET images contain information about tissue function.
Can I eat or drink before my scan?
This will depend on the type of study, but typically, you will be asked not to eat or drink anything after midnight the night before your scan.
How much time should I allow?
You can expect to be in the PET center for one and a half to three hours. The actual scan itself takes far less time.
How does the procedure work?
To begin the procedure, a small amount of radioactive glucose (or similar tracer) is injected into your bloodstream.
There is no danger to you from this injection. Glucose (also known as sugar) is a common substance every cell in your body needs in order to function. Radioactive glucose must pass multiple quality control measures before it is used for any patient injection. The radiation exposure associated with PET is similar to that associated with a conventional CT scan.
After the injection, you will wait approximately an hour, while the injection material is distributed throughout your body.
Then, you will be asked to lie on a table that passes slowly through the scanner. The scanner resembles a CT scanner, but has a much larger opening. Some people fall asleep during the scan.
When disease strikes, the biochemistry of your tissues and cells changes. In cancer, for example, cells begin to grow at a much faster rate, feeding on sugars like glucose. PET works by using a small amount of a tracer drug chemically attached to glucose or other compounds. You are injected with the tracer. It travels through your body emitting signals and eventually collects in the organs targeted for examination. If an area in an organ is cancerous, the signals will be stronger than in the surrounding tissue. A scanner records these signals and transforms them into pictures of chemistry and function.
How will I feel afterwords?
You should feel fine. There are no side-effects from the injected tracer. If you have a heart scan, you may feel flushed afterward.
How do I get a PET/CT scan?
Will my insurance cover a PET/CT scan
Most insurance companies pay for clinically indicated PET procedures. To be clinically indicated, the PET scan must be potentially beneficial in providing information supportive of a diagnosis or monitoring certain conditions.
Many insurance companies have coverage policies for certain clinical situations where PET scans have been proven to be useful. Since PET is a growing field, the data sometimes lags behind coverage policies. Therefore, the indication may be covered, even though it may not be on the standard coverage list. This does not mean that the insurance company will not pay for a clinically indicated PET scan. It is important to contact your insurance company to determine if the PET scan is covered.
Most insurance companies require pre-authorization for a PET scan. Physicians routinely provide clinical information to the insurance company to obtain the pre-authorization. Many coverage policies are local, so it is important to determine the coverage policies from the major payers in your area.
Is PET Safe?
The risks associated with a PET scan are minimal. Most studies are conducted with an injection made up of radioactive glucose (sugar). The radiation exposure associated with PET is similar to a conventional whole-body diagnostic CT scan.
What is a radiopharmaceutical?
A radiopharmaceutical is a radioactive drug. The most commonly used radiopharmaceutical is FDG, which is a radioactive form of glucose. Radiopharmaceuticals are produced by pharmacists and chemists.
What is FDG?
FDG is a type of glucose and is the most commonly used tracer in PET. To begin the PET procedure a small amount of glucose is injected into a patient's bloodstream. There is no danger to you from this injection. Glucose is a common substance that every cell in your body needs in order to function. Diabetic patients need not worry; it would take 1,000,000 doses of FDG to equal the glucose in 1 teaspoon of sugar.
FDG has a half-life of approximately 110 minutes, so it is quickly expelled from your body. FDG must pass multiple quality control measures before it is used for any patient injection.
What happens after my scan?
After your scan, you will get up from the scanner bed and check out with the receptionist. You will be notified when your results will be available.
How often should I have a PET scan?
If you are under a physician's care, you should follow your physician's recommendations for the frequency of having a PET scan. Typically, it is suggested that you have a follow-up scan at least every five years.
Regardless of how advanced science becomes, however, it should be noted that a PET scan cannot replace the benefits of a clinical exam and evaluation performed by your physician.
What do the results mean?
The results will be available from you physician usually within 24 hours of your PET scan. An interpretation by the radiologist or nuclear medicine physician, in layman's terms , will accompany your PET scan results.
Can I see my results?
Yes, your physician will have the PET scan results usually within 24 hours of your PET scan.
Are there alternatives to PET?
Yes and no. There are examinations that you can have performed. CT and MRI, for example, both examine the anatomical (physical) structure. Therefore, they can be useful in determining the size and location of a tumor; however, neither of them can determine the tumor's viability, whereas PET can determine whether a tumor is still active.
What should I do if my physician doesn't know about PET?
If your physician doesn't know about PET, you can direct them to Physicians' Pages for additional information.
Why is PET not well known? Why have I never heard of PET before?
While PET has been around for years, it has only been in the last few years that PET has moved from the research realm to the diagnostic/clinical sphere.
How many PET studies are performed per year?
Approximately 350,000 PET scans will be performed in 2002. The numbers of scans are increasing dramatically, now that PET is no longer only for research purposes. It is estimated that within the next five years in excess of 2,000,000 PET scans will be performed per year.
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