What is PET-CT ?


PET-CT imaging is a diagnostic exam that visualizes metabolic activity from various tissues.  An injection of a radioactive isotope called FDG will be given to you and will travel through your blood stream.  The FDG molecule acts like sugar and will be picked up by cells in your body.  These cells containing a small amount of radioactivity can be imaged by the PET-CT scanner to generate images.  The CT portion is imaged first followed by the PET portion.  After the two images are completed the computer will generate a third set of images called fused PET-CT.  The fused images are a combination of the CT and PET images together.  PET-CT's whole body capability is useful for the detection of metastasis and the staging of various cancers.  FDG PET-CT can also be used to assess myocardial viability and patterns of brain metabolism. 


  • Whole Body Imaging  

  • Head and Neck Imaging

  • Melanoma / Multiple Myeloma Imaging

  • Cardiac Imaging

  • Brain Imaging

Pet Study 1 PET Study 2 PET Study 3


What is covered?


It is pertinent to provide documented medical necessity when ordering a PET-CT exam.  Specific indicators and cancers require a pathology report before ordering a PET-CT exam.  The National Oncologic PET Registry (NOPR) is a collaboration of American College of Radiology Imaging Network (ACRIN), the American College of Radiology (ACR), and the Academy of Molecular Imaging (AMI), to ensure access to Medicare reimbursement for certain types of positron emission tomography (PET) scans.  Referring physicians are advised to refer to the published literature to better understand the potential uses of FDG-PET for NOPR-eligible instances as well as covered Medicare PET-CT indications.  Cancer and Indications that are reimbursed by Medicare are not eligible for the NOPR program.  Cancers and Indications that are not covered by Medicare are eligible for the NOPR program.


PET Study 4 PET Study 5


PET-CT usage


PET-CT can be used for:

  • Initial Treatment (formerly known as staging and diagnosis)
  • Subsequent Treatment (formerly known as restaging and monitoring)
  • Treatment Planning


Who will be performing my test?


Your test will be conducted by a certified nuclear medicine technologist or a certified CT technologist.  These individuals attend national training programs which are comprised of training in radiation safety, handling of radioactive materials and techniques for performing PET-CT exams.


What is involved?


Once you arrive to the facility, you will be asked some questions about your medical history.  The technologists will put an IV in your arm or hand.  A small amount of blood will be taken to check your blood glucose level.  After verification of your blood glucose level and the IV is properly working, you will be injected with a radiopharmaceutical called FDG.  This injection will not make you feel any different or have any side effects.  After the injection, you will be left alone approximately for 60 minutes while the material is circulating through your blood stream.  During this time it is important to remain motion-free and as quiet as possible.   


After the waiting period, you will be instructed to empty your bladder.  Imaging will be done lying on your back on the imaging table for 25-45 minutes. 


PET Scanner


What to expect?


  • Plan on being at the facilities for 2-3 hours.
  • Wear comfortable clothes and avoid wearing jewelry or metal objects on your clothing.
  • If you are claustrophobic, you may ask your ordering physician to prescribe medication.
  • You will be expected to lie on your back during the exam.
  • In most cases your arms will be above your head during the scan.
  • If you are diabetic, please let your ordering doctor and the facility know. Special instructions will be given to you.
  • Please let the facility know if you are pregnant, think you may be pregnant, or you are a nursing mother.
  • Accompanying family and friends will be asked to leave the PET-CT area before you are injected with radioactive FDG.


PET-CT patient preparation


Before scheduling a PET-CT exam:

  • No barium exams 72 hours prior.
  • Patient should be 7-10 days post medical oncology treatment.
  • No biopsies 1 week prior.
  • No radiation treatment for 3 months prior.
  • No major surgeries for at least 6 weeks prior. 


The day before the PET-CT exam:

  • No strenuous exercise for 24 hours prior.     
  • No eating instructions are required the night before.


The day of your PET-CT exam:

  • Do not eat or drink anything other than water for 6 hours prior.
  • Do not drink flavored water.
  • May take your morning medications with water.  Medications required to be given with food should be taken at the end of the exam.
  • No gum chewing, hard candy or mints.
  • No caffeine products 6 hours prior.
  • Wear minimal about of jewelry and metal objects.


Diabetic Patients:

  • Your blood sugar must be below 200 mg/dl in order to perform the PET-CT exam.
  • You may take your oral diabetic medications 4 hours before the exam.
  • You may take half of your insulin dose 4 hours prior to the exam.
  • Please shut your insulin pump off 4 hours before the exam.
  • Diabetic patients may eat a light high protein breakfast and drink only water 4 hours prior to their PET-CT exam.  Do not consume any fruit juices, coffee with cream, fruit or bread.


After your exam


It is advised to avoid pregnant females, animals and small children for an additional 4 hours after your scan. 

In most cases, a patient will be able to drive home after a PET-CT exam.  However, claustrophobic patients

may be given a medication for relaxation.  In these instances, the patient would need someone to drive them home. 

You can resume back to a normal diet and should drink extra fluids to flush the FDG out of your system.