PET Scan (Positron Emission Tomography) | MedStar Health

A PET scan is a non-invasive procedure that produces powerful images of the metabolic, physiologic, and biochemical activity in the body to better characterize the nature and extent of the anatomic abnormalities. A PET scan can show abnormalities that other imaging techniques may not detect, resulting in early and more accurate diagnosis, appropriate treatment, and closer monitoring.

How to prepare for a PET scan

Preparing for a PET scan will include:

  • Names of medications you are currently taking
  • Obtaining a brief medical history, including diabetes and any known allergies
  • Documenting any chemotherapy, radiation treatments, or surgery you may have had and when

PET/CT instructions

It is very important that all instructions are followed:

  • Please do not eat for at least six hours prior to your scan
  • Please drink plenty of water during the six-hour fast
  • The day before the scan, please reduce your intake of sugars and carbohydrates and eat plenty of proteins (beef, chicken, fish, etc). For the last meal of the day prior to your scan, please avoid breads, potatoes, pasta, rice, and fruit for dinner
  • Head/neck cancer patients: please minimize talking two hours prior to your scan appointment time
  • Please, no exercise or strenuous activities for 24 hours prior to the scan. This includes heavy lifting, running, sporting activities, and physical therapy
  • Please do not chew gum; avoid candy and sodas 24 hours prior to scan. Please do not use mouthwash the day of the scan
  • You can take your medications if you are able to take them on an empty stomach on the day of the test. Avoid steroid and hormone medications 24 hours prior to your exam time. Please bring a list of your medications with you
  • Please avoid wearing jewelry, metal buttons, and metal zippers during the scan
  • If you are diabetic and have an afternoon appointment, we ask that you eat a light breakfast (toast and egg and then return to fasting thereafter) four hours before your scan. During this time, you are able to take your meds with a glass of water
  • If you take pills for your diabetes, please ask for special prep from our PET/CT scheduler at 202-444-3363
  • Please be advised that the entire procedure takes approximately two hours; you must be able to lay down without moving for at least 30 minutes
  • If you had a CT/MRI at a facility other than Georgetown University Hospital, please remember to BRING YOUR FILMS/CD WITH YOU. The facilities usually require at least 48 hours' notice to pick up your films

On the day of your appointment

On the day of your appointment: Please bring your insurance cards, photo id, co-pay (if indicated), and original PET/CT order from your referring physician with you to your appointment. Please arrive at the registration area of the Nuclear Medicine Department on the second floor of the Gorman Building, Room G2014 to check in and register for your PET/CT scan.

What to expect during your appointment

  • After registration, you will be greeted by our experienced nuclear medicine technologists and escorted back to the PET/CT suite where they will take a small blood sugar sample and then place a small IV line in your arm for a simple injection of the PET/CT tracer, called 18-FDG (Fludeoxyglucose), a glucose analog
  • Following the injection, you will be asked to sit back, rest and relax for 60 minutes to allow the FDG to uptake in your system and adequately target and bind to any possible cancer cells within your body. This timing allows for the best imaging results
  • You will then be imaged on the PET/CT scanner lying flat for about 30 to 45 minutes

Benefit of PET/CT in oncology

Clinical research data has proven that PET/CT scanning is superior to other conventional imaging modalities in the diagnosis and management of various types of cancers. Additionally, the appropriate use of PET/CT can lead to a significant change in the management of a patient’s care and possibly save valuable healthcare resources and enhance patient outcomes.

MedStar Health’s Georgetown Lombardi Comprehensive Cancer Center’s commitment to providing the best in patient care continues within our Nuclear Medicine Department. The PET/CT scan is often considered one of the most powerful imaging tools and has often become the cornerstone in the management of a wide array of cancers.

The management of cancer has made significant advances over the years with improved treatment options in the areas of surgery, chemotherapy, and radiation oncology. Personalized medicine and individualizing treatment in cancer patients are important evolving concepts at this time; metabolic imaging, such as PET/CT scans play an essential role in this area through diagnosis, disease staging and metastatic spread, monitoring response to treatment, planning and choosing of appropriate therapies, detecting recurrence, and characterizing tumor biology, which may play a role in prognosis. PET/CT scans allow physicians to see cancer in its earlier stages, localize and individualize treatment and treat it with precision, carefully monitor the efficacy of the treatment without delay, and determine a new course of treatment action should it be necessary. PET/CT is now regarded by many to be the ‘one-stop imaging’ choice for several cancers.

Our PET/CT center is fully integrated into the medical oncology, surgery, and radiation oncology teams at Georgetown Lombardi Comprehensive Cancer Center. Each of the areas have computerized access to images we produce to provide up to the minute information for patient management.


Major tumor types:

Other Conditions/indications

  • Heart disease: PET scans of the heart determine blood flow to the heart muscle and help evaluate signs of coronary artery disease. These scans can verify that areas of the heart that show decreased function on the imaging are alive or scarred because of a prior heart attack. Combined with a myocardial perfusion study, PET scans can differentiate between non-functioning heart muscle and heart muscle that would benefit from a procedure, such as angioplasty or coronary artery bypass surgery, to re-establish adequate blood flow and to improve heart function.

  • Brain disorders: PET scans of the brain are performed to evaluate patients with memory disorders, such as Alzheimer’s or dementia, suspected or proven brain tumors, or seizure disorders that are not responsive to medical therapy and make the patient a candidate for surgery.

Our providers

Radiologist and medical technician at the computer tomography getting a scan

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