What is a PET scan? Uses, procedures, and risks

What is a PET scan?

Imaging tests, such as positron emission tomography (PET) scans, show the metabolic and biochemical function of your organs and tissues.

PET scans enable your doctor to see problems within your body. A specific dye with a radioactive tracer is used during scanning. The tracer is absorbed by specific organs and tissues, which allows your doctor to determine how well your organs and tissues are working.

Because some biological tissues and diseases have higher levels of chemical activity than others, the tracer will accumulate in areas of higher chemical activity. On a PET scan, these diseased areas will appear as bright spots.

The scan assesses a variety of things, including blood flow, oxygen use and how your body uses sugar.

Since a PET scan is usually performed as an outpatient treatment, you can resume your normal activities as soon as the test is finished.

What does a PET scan test for?

To check your blood flow, oxygen intake, or the metabolism of your organs and tissues, your doctor may order a PET scan. PET scans provide your doctor with potentially clearer insight into complex systemic disorders because they reveal problems at the cellular level.

Often, PET scans are used to look for:

  • cancer
  • heart problems
  • Brain diseases, such as central nervous system (CNS) disorders


Cancer cells may have a higher metabolic rate than normal cells. Cancer cells often appear as bright spots on PET scans due to high levels of chemical activity. so, PET scan Very helpful in detecting cancer.

heart disease

PET imaging can be used to identify areas of reduced blood flow in the heart. This is because healthy cardiac tissue absorbs more of the tracer than tissue that is diseased or has less blood flow.

Your doctor can use this information to decide how to proceed with further treatment, if necessary.

brain disorders

Glucose is the brain’s primary fuel source. Tracers are attached to substances such as glucose during a PET scan. PET scans can reveal which parts of the brain are taking up more glucose by detecting radioactive glucose.

A doctor can check how the brain works and interpret the scan to find any abnormalities.

PET scan procedure

A PET scan is a type of nuclear medicine imaging procedure.

A PET scan requires you to lie on your back on a retractable table that slides into the scanner to start the procedure.

A PET scan is a 100% painless test but due to the enclosed nature of the PET scan machine, it can be somewhat uncomfortable for those who fear confined spaces.

If you are claustrophobic or uncomfortable in tight spaces, talk to the technician before the test.

You may be given a mild sedative to help you relax and go through the PET scan exam smoothly.

Your healthcare professional can view the image on a monitor.

How do I prepare for a PET scan?

  • Remove any metal objects such as keys, jewelry, belts, wallets, etc.
  • Bring your medical history along with any previous scans.
  • Take dietary advice from the doctor at least 2 days before the exam.
  • Because PET scans change the body’s blood sugar, diabetics should consult their doctor about the potential risks and how to minimize them.
  • If you are being tested for heart problems, avoid caffeine 24 hours before the test.
  • A radioactive tracer is injected about 30 to 60 minutes before the test, after which you need to rest to allow the tracer to dissolve.

What are the risks and side effects?

  • A PET scan should not be performed on pregnant women because the radiation can harm an unborn baby. If you are pregnant, avoid PET scans.
  • Mothers who are nursing should not have a PET scan. But if they have to, they should pump and store breast milk before the test, because they can’t resume breastfeeding for 24 hours after the test.
  • A brief stinging sensation will be felt after trace element injection, but it will not last. However, the area is likely to bruise and swell.

Last thought

PET scans are just as helpful for early diagnosis of disease as they are for monitoring disease progression. They are especially useful in determining how well you are responding to cancer therapy when tumors begin to shrink.

PET can also be used to assess brain or heart damage after a stroke or heart attack. This can help predict your long-term outcome and give the healthcare professional a roadmap of functional tissue (prognosis).

Additionally, to stay on top of your health it is vital to keep a check on your overall health for a happy life through regular health checkups.

Book a full body wellness exam today!

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