Shields PET/CT at Cooley Dickinson Hospital

If you have any questions, please contact us at 866-258-4738 (or 877-712-3075 for billing questions).

What is PET/CT?

PET/CT is the most advanced medical imaging technique available today. It combines PET’s ability to detect changes in cell activity with the fine structural detail that CT scans provide. This revolutionary technology enables your physician to detect the presence of disease earlier and pinpoint its location with much greater accuracy than PET or CT scans alone. PET/CT scans provide a powerful tool for diagnosing and staging cancer and differentiating Alzheimer’s disease from other forms of dementia.

How does PET/CT work?

Growing cells use glucose, a form of sugar, as a major source of energy. In preparation for a PET/CT scan, patients are given a small amount of a glucose that emits tiny particles called positrons. More active cells, such as cancer cells, use more glucose than normal cells and will have higher concentrations of positrons during the test. The PET/CT scan detects the positrons and creates highly detailed images that show the precise location of the abnormal cells and whether there is increased activity in the surrounding tissue. PET/CT scans provide remarkably clear pictures of what is happening in the body, often eliminating the need for additional tests and/or exploratory surgeries.

Why do I need this exam?

A PET/CT scan will enable your doctor to identify a potential health problem faster and more accurately than other diagnostic procedures. If a disease is detected, the PET/CT scan helps your physician assess what stage it has progressed to (i.e. how widespread it is), identify the best treatment approach and/or monitor your progress. If you have questions about your treatment, ask your physician what he or she hopes to learn from your PET/CT exam.

How do I prepare for a PET/CT scan?
  • You should not eat or drink anything (including candy, and do not chew gum) for four to six hours before your test. However, we highly recommend you drink plenty of water.
  • If you are not on any dietary restrictions you should eat a low carbohydrate diet during the 18 to 20 hours prior to your exam.
  • Avoid any physical exertion 24 hours prior to your exam; this would include physical activities such as yoga, walking, running or weight lifting.
  • You should continue to take any medications prescribed by your physician. You need to take your medications with food, take them with a few soda crackers four to eight hours before your exam.
  • If you are a diabetic, please let us know ahead of time so we can work with your physician to determine the best way for you to prepare for the scan.
  • If you are or think you may be pregnant, discuss this with your physician; generally, PET/CT scans are not performed during pregnancy.

What to wear:

  • The scanner room is cool, so you will want to wear warm, comfortable clothing.
  • We recommend sweatpants and sweatshirts so you will not need to change for the exam.
  • Avoid clothes with heavy buckles or other metal components.

What to bring with you:

  • Your insurance card(s)
  • Previous CT scans, PET scans and X-rays
  • A copy of your medical history and a list of your medications
  • A copy of any previous pathology reports
  • Personal reading materials or music

Please arrive one hour before your scheduled appointment. If you need to cancel or reschedule, please do so at least 24 hours before your appointment.

What happens when I arrive?

After you register you will go to an area to prepare for the exam. A small IV line will be put in your arm to give you the glucose needed for the test. You will be asked to rest without talking for 50 to 60 minutes as the glucose is absorbed into your body. You may also need to take an oral contrast agent, depending on the type of PET/CT you are having. The actual scan will take about 20 to 30 minutes.

After your scan

You can leave immediately after the exam. You may drive if you wish and resume all of your normal activities; there are no restrictions on your diet or exercise, and you should take your prescribed medications. As a precaution, we recommend that you avoid close contact with infants or with anyone who is pregnant for eight hours after the scan. Your PET/CT scan will be reviewed by a physician who will send a report to your doctor, who will then contact you to discuss the results of the exam.

If you have any questions, please contact us at 866-258-4738 or visit or consult your physician with any additional concerns.


Need to reschedule?

If you need to reschedule your visit, please call our scheduling department at least 24 hours in advance of your appointment at 866-258-4738

Billing questions?

Contact our Patient Financial Services team at 1-877-712-3075