A PET test, also known as a positron emission tomography (PET) scan, is a type of nuclear medicine imaging test that measures metabolic activity in the body. PET scans are used to diagnose and treat a variety of diseases, including cancer, heart disease, and Alzheimer's disease.

What is PET Test?

How Does a PET Test Work?

A PET scan uses a radioactive tracer, which is a small amount of radioactive material that is injected into the body. The tracer travels through the body and is absorbed by cells that are active and using energy. A special camera detects the radiation emitted by the tracer, and a computer creates images of the areas of the body where the tracer is concentrated.

What are the Different Types of PET Scans?

There are several different types of PET scans, including:

  • Fluorodeoxyglucose (FDG) PET scan: This is the most common type of PET scan. FDG is a radioactive tracer that is taken up by cells that are using glucose, a type of sugar. FDG PET scans are used to diagnose and monitor cancer, as cancer cells tend to use more glucose than normal cells.
  • Fluorocholine (FCH) PET scan: This type of PET scan uses FCH, a radioactive tracer that is taken up by cells that are dividing. FCH PET scans are used to diagnose and monitor prostate cancer, as prostate cancer cells tend to divide more quickly than normal cells.
  • Dopamine transporter (DAT) PET scan: This type of PET scan uses a radioactive tracer that is taken up by dopamine transporters, which are proteins that help to regulate dopamine levels in the brain. DAT PET scans are used to diagnose and monitor Parkinson's disease, as Parkinson's disease is caused by a loss of dopamine neurons in the brain.

What are the Benefits of a PET Scan?

PET scans offer a number of benefits, including:

  • Accuracy: PET scans are very accurate in diagnosing and monitoring diseases.
  • Non-invasive: PET scans are non-invasive, meaning that they do not require surgery or the insertion of needles into the body.
  • Quick: PET scans are relatively quick, taking only about 30 minutes to an hour.
  • Safe: PET scans are generally safe, with few side effects.

What are the Risks of a PET Scan?

The risks of a PET scan are generally low, but may include:

  • Allergic reaction to the radioactive tracer: Some people may experience an allergic reaction to the radioactive tracer, such as hives, rash, or swelling.
  • Radiation exposure: PET scans involve exposure to a small amount of radiation. The amount of radiation exposure is generally low, but it can increase the risk of cancer slightly.

How Do I Prepare for a PET Scan?

Before a PET scan, you will need to:

  • Fast for at least 6 hours before the scan.
  • Avoid drinking caffeine or alcohol for at least 24 hours before the scan.
  • Tell your doctor about any medications or supplements you are taking.
  • Wear comfortable clothing.

What Happens During a PET Scan?

During a PET scan, you will lie on a table that slides into a large machine. A small amount of radioactive tracer will be injected into your arm or hand. The tracer will travel through your body and be absorbed by cells that are active and using energy. A special camera will detect the radiation emitted by the tracer, and a computer will create images of the areas of the body where the tracer is concentrated.

What Happens After a PET Scan?

After a PET scan, you will be able to go home. You may have some residual radioactivity in your urine or sweat for a few days after the scan. This is normal and does not pose a health risk. You should drink plenty of fluids after the scan to help flush the radioactive tracer out of your body.

Your doctor will review the results of your PET scan and discuss them with you. The results of your scan may help your doctor to diagnose your condition and develop a treatment plan.