Update HSHS to remain in-network for Illinois Aetna click here to read more

PET/CT Scans

Diagnostic imaging tool that combines metabolic activity of the body tissue with their structures.

Patient entering CT tube

The body’s tissues use glucose (sugar) molecules for energy. By labeling glucose with a radioactive tracer, Fluorine-18 (FDG), Nuclear Medicine scanners are able to identify abnormal glucose use in the body’s tissues. Metabolic abnormalities can indicate the presence of diseases like cancer, heart disease, or changes in the brain.

How does the procedure work:

A small amount of blood will be drawn in order to determine your blood sugar level. Once your blood sugar is confirmed to be low enough for the procedure, you will be given an injection of the radioactive tracer, Fluorine-18 (FDG). After the FDG is administered, you will rest quietly for 45 minutes while the tracer circulates through your body’s tissues. After the resting time, you will be taken into the facility to empty your bladder of any FDG that has collected while your were resting. You will then be taken to the Nuclear Medicine Technologist who will help you onto the imaging table where you will lie during the 20 to 30 minute scan.

The radioactive tracer, FDG, is injected into the bloodstream which distributes it throughout the body’s tissues. The cells then contain small amounts of radioactivity, which the PET scanner is able to detect and generate into an image of the body’s tissue metabolism. This PET image is then analyzed for abnormalities that could indicate diseases. PET/CT combines this metabolic PET image with the anatomical image of a CT scan. This give physicians a very precise image of both the body’s tissue function and structure in order to provide more accurate diagnosis and treatment planning.

How do I prepare for the PET / CT Exam?

  • Do not eat or drink anything except WATER for 6 hours before your exam.
  • Drink plenty of WATER before the exam.
  • Wear warm, comfortable clothing that does not contain metal parts.
  • Take any medications as normal, with WATER.
  • Let the personnel know if you are DIABETIC.
  • Let your physician and the personnel know if you are CLAUSTROPHOBIC or PREGNANT.
  • Prepare to spend 1 ½ hours at the exam.

What are the risks of the PET / CT Exam?

There are none – the quantity of radiation is very low, similar to a CT scan, lung, bone, or heart scan. The radiopharmaceutical tracer is only in your body for a few hours and flushes out naturally.

What happens after the exam?

You are free to resume your normal diet. You should drink additional fluids after the exam to help your body flush out all the radiopharmaceutical (FDG).