OSF HealthCare St. Mary Medical Center


Experience advanced imaging capabilities with PET-CT scans at St. Mary's Hospital. Our state-of-the-art technology combines PET and CT scans to provide detailed insights into various medical conditions, aiding in accurate diagnosis and treatment planning with exceptional precision and efficiency.

What is PET/CT?

Positron Emission Tomography (PET) and Computerized Tomography (CT) helps a physician diagnose and manage your care. The highly sensitive PET scan detects changes in cellular function; how your cells are utilizing nutrients like sugar and oxygen. The CT scan provides a detailed picture of the internal anatomy.

Alone, each imaging test has particular benefits and limitations but when the PET and CT scans are "fused" together, the combined image provides complete information that enables your physician to make an earlier diagnosis. These capabilities can lead to a faster start on the best possible treatment while avoiding invasive exams or exploratory surgery.

The Day of Your Exam

After reviewing your history and any prior exam, we will test your blood sugar, and then you'll receive an injection. After the injection, you'll be asked to rest comfortable for 30 to 90 minutes.

Please follow these instructions for your PET/CT examination:

  • Do not eat or drink anything but water for six hours before your exam.
  • Do not chew gum or suck on mints for six hours prior to your exam.
  • If you take daily medications, please contact your physician to determine the best way to take your medications before the exam.
  • If you are diabetic, let us know ahead of time so we can work with your physician to determine the safest possible way for you to prepare for your exam.
  • If you are pregnant or breast-feeding, please let us know prior to your exam.
  • Avoid caffeine for 24 hours prior to your exam.
  • Avoid exercise for 24 hours prior to your exam.

The Scan

You'll lie on a comfortable table that moves slowly through the ring-like PET/CT scanner as it gathers the information it needs to generate diagnostic images. We'll ask you to lie very still because movement can interfere with the result. The exam is painless and usually lasts anywhere from 15 to 60 minutes.

How Long Will It Take?

The length of your exam will vary depending on what procedure your physician has ordered. The average length of a PET/CT procedure is 30 to 90 minutes, including the resting period.

After the Exam

You may leave as soon as the scan is complete. Unless you've received special instructions, you'll be able to eat and drink immediately. Drinking lots of fluids will help remove any of the radiopharmaceutical that may still be in your system. You'll be able to resume all of your normal activities.

In the meantime, the radiologist will interpret your exam and the interpretation will be forwarded on to your physician.

Issues Associated with PET/CT

A PET/CT study is similar to many other diagnostic procedures from CT and MRI to Nuclear Medicine. The radiation you receive is equivalent to what you'd get from having a couple of X-rays.

The injection you receive before your PET/CT exam does not remain in your system. There's no reason to avoid interacting with other people once you've completed your exam. To be extra safe, wait a few hours before getting too close to an infant or anyone who's pregnant.