PET/CT Scan Frequently Asked Questions

A PET/CT scanner is an advanced imaging machine that performs two kinds of scans – PET scans (positron emission tomography) and CT scans (computed tomography) in one appointment. Both scans create very detailed pictures of the body’s organs and tissues.

These scans can help doctors find certain medical problems before they show up on other imaging tests.

A PET scan creates images that reveal how tissues and organs function. It's often used to find medical problems such as:

• Cancer
• Heart problems
• Lung disease and lung nodules
• Brain disorders
• Conditions that affect the central nervous system

A CT scan creates images of the body’s organs, bones and other tissues. CT scans are used to find a wide range of problems, including:

• Bone and joint conditions
• Cancer
• Heart disease
• Lung conditions
• Internal injuries

Doctors order PET scans when they want to examine blood flow, oxygen intake, or see how the body’s organs and tissues are working. PET scans can give important clues about the presence of disease or how it is progressing.

These scans are often used to diagnose or monitor cancer, but they are also useful for imaging the heart and brain.

Before getting a PET scan, a Temple staff member will explain to you how to prepare. You may be asked not to eat or drink anything for several hours before the scan.

Metal objects such as jewelry, eyeglasses, dentures and hairpins should be removed before the scan. You may also be asked to remove hearing aids and removable dental work. Do not hesitate to ask questions if anything is unclear.

When you arrive for your PET scan, someone will discuss the procedure with you and ask if you have any questions. When you are ready for your scan, you will have your blood sugar tested.

Next, most patients will receive an oral contrast (barium drink). An IV will be started, and you will receive an injection of a small amount of radioactive liquid. You will then be asked to wait very quietly.

During the actual scan, you will lie on a bed that passes slowly through the scanner. You will be asked to remain still on the bed during the scan. The length of the scan will depend on the body areas being studied. You should be able to return to normal activities immediately after the scan.

During a PET scan, a small amount of radioactive dye (called a “tracer”) is injected into a patient’s vein. Sometimes this tracer may also be swallowed or inhaled as a gas. This tracer is absorbed by certain organs and tissues.

The scanner then detects this tracer, allowing it to create detailed images of a patient’s blood flow, oxygen intake, and how well their organs and tissues are functioning. The tracer quickly passes out of the body without causing any harm.

You will be exposed to small amounts of radiation during a PET scan, but this carries a very low risk. The benefits of a PET scan are usually much greater than the risks.

The actual scan usually takes between 25 to 50 minutes. Expect the entire appointment to last up to several hours.

The doctor who ordered the PET scan will discuss the test results with you.