• Clinical Services
  • For Patients
  • For Visitors
  • Medical Professionals
  • Hospitals & Locations
  • Our Story
  • Find a Career
  • Find a Physician
  • My Account
  • Make a Payment
Skip Navigation


Considered a powerful diagnostic breakthrough, PET/CT is a technology that combines images from the highly sensitive PET scan, which detects changes in the way cells behave, with detailed pictures of internal anatomy from the CT scan.

After the PET and CT scans are obtained, computer manipulation allows the two exams to be viewed independently, as well as in a superimposed form. This combined image shows precisely where abnormalities exist, making it possible for earlier cancer and heart disease diagnosis, accurate staging and more precise treatment and monitoring. The PET/CT image also provides early detection of the recurrence of cancer, revealing tumors that may otherwise be obscured by scarring that results from surgery and radiation therapy, especially in the head and neck areas.

Mobile PET/CT Scan

St. John Providence has partnered with Medical Outsourcing Services, one of the largest providers of PET and PET/CT services in the Midwest to bring PET/CT to the communities they serve. The PET/CT scanner is a product of General Electric. St. John Providence is one of the first health systems in the state to offer a mobile PET/CT scanner. PET/CT is one of the most advanced diagnostic technologies available.

What is PET/CT?

Positron Emission Tomography / Computed Tomography, or PET/CT, is non-invasive test that is a proven molecular imaging technique. As the name implies, it combines two scanners into one. The extremely sensitive PET scan shows the physiological aspect of the organs and tissues, thereby providing very critical information about the metabolic function at a very early age, often before anatomical changes takes place. The CT scan provides detailed information about the body’s anatomy such as size, shape and location. With the combination of a PET/CT scanner, the clinician is provided with a powerful tool that will assist in the diagnosis and staging of certain cancers, earlier and more accurately. In doing so, it will help aid in the development of the most effective treatment plan for you.

Even though the primary use of PET/CT is managing oncology patients, it may also be utilized for the diagnosis of and assessment of cardiac diseases and neurological disorders, such as, Alzheimer’s disease and seizure disorders. 

Frequently Asked Questions

Why is PET/CT beneficial?

  • In cancer: PETCT is a safe and painless way to provide your physician with valuable information. It may help diagnose the extent of the disease, guide the most effective therapy option and help evaluate if the treatment is effective.
  • In the heart: PETCT can quantify the extent of heart disease. And also determine, after a heart attack, if the heart muscle would benefit from surgery.
  • In the Brain: PETCT can diagnose Alzheimer’s disease for early intervention, locate tumors in the brain and distinguish from radiation scar versus reoccurrence, locate the focus of seizure activity for some patients with epilepsy.
  • PET images different than more conventional images such as CT, MRI, Ultrasound and general x-ray. These images show what the tissue looks like, where as PET images show how the tissue is functioning. So by combining PET and CT the physician is able to see detailed anatomy while looking at the metabolic function of tissue cells.

Will I be exposed to radiation?

  • Yes. However, we strive for providing the highest quality image achieved with the lowest dose possible.

Are there any harmful side effects from having a PET/CT?

  • No, there are no harmful side effects from a PET/CT scan. The only pain involved is the prick from the small IV prior to the injection of FDG.

What is FDG?

  • FDG is an acronym for Fluorodeoxyglucose. FDG is a radioactive molecule that is similar to glucose (sugar) and is the most commonly used imaging tracer for PET imaging. The half-life of FDG is 110 minutes so it is rapidly cleared through your system.

Will my insurance cover a PET/CT scan?

  • Yes, most insurance companies pay for clinically indicated PET scans. Since PET is a growing field, the data sometimes lags behind coverage policies. Therefore, the indication may be covered, even though it may not be on the standard coverage list. It is important to contact your insurance company to determine if the PET scan is covered.
  • Most insurance companies require pre-authorization for a PET scan. Physicians routinely provide clinical information to the insurance company to obtain the pre-authorization.

How long does the test take?

  • You should plan on being at the PET/CT center for approximately 2 to 3 hours. However, the actual image time is 15 to 45 minutes, depending on type of procedure.

What can I expect on day of my appointment?

  • Please arrive to the PET center 30 minutes prior to your scheduled appointment.
  • The PET/CT staff will greet you and you will be asked to fill out a brief medical history form.
  • Your blood sugar will be checked by a finger stick test, the goal is to have a blood sugar less than 200 mg/dl and a small IV is inserted into the vein of your arm.
  • A small amount of a radioactive glucose (sugar) called FDG is injected through the IV. Following the injection, you will be asked to lie quietly in a room for 50-60 minutes. This is considered the uptake phase of the exam.
  • After the uptake you will be asked to use the restroom to empty your bladder. You then will be imaged on the PET/CT scanner.
  • During the scan you will be asked to lay on your back with both arms raised above your head. If you think you are unable to hold your arms above your head, please inform the technologist and they will try to accommodate you.
  • The table will move through the “donut” shaped hole of the scanner slowly. You will be asked to hold very still and breath normally. Any motion during the scan can interfere with the results.
  • The total time of imaging is approximately 15-45 minutes, depending on your type of procedure.

What do I do after the exam is finished?

  • You may leave immediately after your scan is completed.
  • Your activity will not be restricted. You may drive if you wish, resume your normal diet, exercise and take your normal prescribed medication.
  • As an extra precaution, avoid getting close to infants and pregnant women for eight hours following your test.
  • Drinking extra fluids may help eliminate any extra radioactive sugar in your system.

When will I get the results of my test?

  • A Radiologist will review your PET/CT scan and your physician will have a written report within 2-3 business days after your scan.
  • Your physician will contact you with the results.

View our PET/CT services brochure.


Find a Physician

St. John Hospital

22101 Moross - Map
Detroit, MI 48236


General Visiting Hours
11 a.m.-8 p.m.
Visitor Info - Parking Info

Watch what our "family" at St. John Hospital & Medical Center is thankful for.