PET-CT Scan Preparation

PET is an acronym for Positron Emission Tomography.

PET is a test that uses special imaging cameras and a radioactive type of sugar to produce pictures of the function and metabolism of the cells in the body.

CT stands for Computed Tomography.

CT is an x-ray test that generates a detailed view of the anatomy or structure of organs and tissues in the body. The CT scan can show the dimension of vessels, lymph nodes and organ systems.

A PET/CT scan depicts both technologies using a single machine. It provides a picture of function (PET), a picture of anatomy (CT) and a merged picture of both the body’s metabolism and structure.


Exam Preparation

All Patients

  • Do not eat 6 hrs prior to the appointment
  • May drink water, but no other liquids
  • Do not have any caffeine, gum, cough drops or mints
  • May take regularly scheduled medications if they can be tolerated on an empty stomach
  • No strenuous exercise 24 hours before your appointment
  • Wear warm, loose-fitting clothing(i.e. sweats, flannel shirt, etc.)
  • Please do not wear any jewelry

Non-Insulin Dependent Patients:

  • Take oral medications
  • Have light breakfast
  • May drink water, but no other liquids
  • Bring glucometer with you to the appointment

Insulin Dependent Patients:

  • Take insulin
  • Eat a regular meal 4 hours prior to appointment
  • May drink water, but no other liquids
  • Bring glucometer with you to the appointment


The PET/CT Exam

Prior to the exam you will receive a small injection of radioactive sugar (FDG).

You will be asked to sit or lay down on a comfortable chair or bed for about 45 minutes while the FDG travels throughout your body. After this time, the technologist will assist you to the scanner.

The CT portion of the exam is completed first followed by the PET portion. You may be asked to hold your breath for several seconds while the CT scan is performed. The technologist will tell you if this is needed. It is important that you don’t move for the duration of the exam.

The length of the exam is determined by your height and area of interest. Expect to spend approximately 2 hours for your exam, but most of this time is spent preparing for the scan. Most PET/CT scans are typically completed within 20-40 minutes. When the total scan is finished, the computers will produce images for the radiologist to review.


PET-CT Scan Preparation

Once the total scan has been performed you may resume daily activity. Even though the FDG will quickly leave your body, you can expedite the process by drinking plenty of water after your scan is complete.

Your PET/CT images will be read by the reading physician and sent to your referring physician with all the pertinent information.

As a part of PET-CT scan preparation, consult your physician prior to your PET/CT scan if …

  • You are or may be pregnant
  • You are allergic to any food or drugs
  • You are currently being treated for an infection
  • You are unsure if you should take your medications
  • You have had recent radiation therapy