PET scan
What Does a PET Scan Show?
A positron emission tomography (PET) scan is a type of imaging test that uses a small amount of radioactive material, or tracer, to create detailed pictures of organs and tissues inside your body.
A PET scan shows how organs, such as your heart, lungs and brain, are functioning. It can detect diseases with the help of metabolic activities. It can accurately detect the presence of cancer — where it started and whether it has spread, as well as in what amount.
Preparation for a PET Scan
Before you get a PET scan, you must tell your doctor about any medications that you are taking, as certain medications can interfere with the scan and its results. You may be asked to change, stop, or avoid certain medications several days before the scan.
Your doctor may ask you to avoid eating or drinking for 6–12 hours before your test. Also, you should not eat any foods that are high in sugar or carbohydrates two to three days before the scan. This will help the radioactive material to collect in the area of concern in your body.
How a PET Scan Is Performed?
A PET scan usually takes between one and two hours. Your scan may take longer as it may be combined with other imaging tests, such as a computed tomography (CT) scan.
You will be given a special dye made from a small amount of radioactive material. You can get the dye through an intravenous (IV) line in your arm.
Once the dye has entered your system and circulated through your body, it will collect in parts of your body where cells are multiplying at a high rate. When the dye collects in the area of concern, it can show up on the PET scan images.
Types of PET Scans
There are two types of PET scans:
- Full-body PET scan: This scan looks at the entire body. It usually takes two to three hours.
- Region-focused PET scan: This scan looks at a specific area, such as your chest or abdomen. It usually takes one to two hours.
Risks of a PET Scan
A PET scan is a very safe procedure. The amount of radiation used in the test is within the safety limits. But as with any medical procedure, there are some risks associated with a PET scan.
The radiation exposure from a single PET scan is low. But because the radiation used in the test accumulates over time, it can increase the risk of cancer. Children, pregnant women and women who are breastfeeding should only get a PET scan if there are no other imaging options available.
When a PET Scan Might be Recommended?
A PET scan can be used to diagnose a number of conditions, including:
- Cancer, including which type, its stage and whether it has spread
- Brain disorders, such as Alzheimer’s disease, stroke and seizure disorder
- Heart disorders, such as coronary artery disease and congestive heart failure
- Inflammatory conditions, such as rheumatoid arthritis
A PET scan may also be used to monitor the progress of cancer during and after treatment. A PET scan may also be used along with other imaging tests, such as a CT scan, to confirm a diagnosis.
