A PET-CT scan is a procedure that actually uses two different imaging approaches to enable radiologists to look for signs of disease or other problems within the body and to evaluate how organs of the body are functioning: positron emission tomography (PET) and CT (computed tomography).
In the PET scan, the patient is injected with a small amount of radioactive material that circulates through the bloodstream, making tissues and organs of the body, as they function, visible to the imaging equipment.
The CT scan uses X-rays to image sections of the body so that the radiologist can see organ structures or indicators of disease.
Think of the PET scan as creating images that show organs as they are functioning over time, whereas the CT scan creates more of a snapshot of what a section of the body or an organ looks like at a specific instant. PET-CT scans are used for a variety of purposes, including:
- Cancer diagnosis or screening
- Preoperative planning before surgery
- Preparing for or guiding nuclear medicine therapy for cancer
- Diagnosis or screening for heart disease
- Diagnosing neurological disorders such as Alzheimer’s or Parkinson’s
Your physician may order a PET-CT scan for different medical reasons, depending on your specific situation.
A PET/CT scan uses very small amounts of glucose (sugar) to make images within the body. The foods you eat affect your blood sugar, which in return may affect the quality of the exam. We have enclosed this list of instructions to help ensure that you have the best possible blood sugar on the day of your scan.
Food and Drink: (required diet to be followed day prior and day of the exam)
- An all meat, eggs, cheese diet ONLY.
- Only drink water. You must be well hydrated.
- Do not eat carbohydrates. This includes potatoes, pasta, rice, breads, chips and pretzels.
- Do not eat cookies, candy, fruit, drink soda pop, alcoholic beverages, coffee or any other beverages containing caffeine.
- Your blood sugar must be between 50-200 in order for us to complete your scan.
- Do not consume any food or drink 6 hours before your scan this includes candy, gum, mints, cough drops and all tobacco products.
- Readi-Cat: (contrast beverage; can be picked up at any of our locations)
- Drink one full bottle of Readi-Cat (barium sulfate) 2 hours prior to your arrival time.
- Absolutely no food or drink after drinking the Readi-Cat.
- We suggest chilling the Readi-Cat.
- Patients taking steroids (i.e. Prednisone, Dexamethasone, Decadron) must discontinue this medication 24 hours prior to your appointment.
- Insulin dependent patients must discontinue Insulin 4 hours prior to your appointment.
- Patients taking Metformin must discontinue this medication 24 hours prior to your appointment. Your blood sugar must be between 50-200 in order for us to complete your scan.
- All other medications can be taken as prescribed by your physician.
- Avoid all strenuous activities and exercise 24 hours prior to your exam.
- Patient cannot have chemo treatment 24 hours prior to appointment.
- We suggest dressing comfortably and in layers to stay warm as the exam rooms are kept cool.
- Please avoid any clothing with large buttons, zippers or any other metal objects on them.
- Suggestions: sweatpants, sweatshirt, pajama pants.
What to expect
After checking in, our staff will check your blood sugar level and you will be injected with a small amount of radioactive sugar. Then, you will be required to sit or lie down for 45-60 minutes. An interview process will take place to obtain your medical history. The actual scan will take about 30 minutes. Please plan on being at the office for approximately 2 hours.
Failure to follow the instructions listed above will result in cancellation of your appointment. You will be responsible for a $175.00 cancellation fee. If you need to cancel or reschedule your appointment, please contact us at 810-244-7100 no later than 24 hours in advance.
Medical Radiation Safety
The radiation doses from a PET-CT scan is considered to be in the “low-level radiation” category. However, since PET-CT scans require more radiation than other types of imaging exams, RMI is committed to managing radiation dose for patient safety, under the principles of the Image Gently program for pediatric patients and the Image Wisely program for adults.
RadiologyInfo.org: Positron Emission Tomography – Computed Tomography (PET/CT)