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What is a PET/CT and why is it done?

*We currently only offer F-18 FDG scans

A PET/CT scan is a combination of a PET (Positron Emission Tomography) scan and a CT (Computed Tomography) scan.  
  • A PET scan uses a radiotracer (a special contrast agent), injected through your vein, to show the metabolic activity (physiology) within your cells.
  • A CT scan uses X-ray radiation to provide thorough images of the structures inside your body (anatomy).
  • By combining both of these exams, the technology creates an incredibly detailed and informative study by showing both your anatomy and physiology. This determines the exact location and degree of abnormal uptake in the body. Many times a PET/CT can identify the disease, even at its early stages before other imaging exams.

How do I prepare for the exam?

  • Starting 24 hours before the test, we want you on a low carb, low sugar diet and no caffeine
    • Limit your amount of bread, pasta, potatoes, rice, and any sugary desserts. We want you to eat high protein foods (including any kind of meat, fish, tofu, etc.) and green vegetables (avoiding the starchy vegetables)
  • No caffeine (including regular and decaf coffee, soda, and chocolate)
  • If you have ingested too many carbs, sugars or caffeine the uptake of the radioactive sugar molecules will be altered, resulting in poor test quality
  • On the day of the test, nothing but water and your normal medications for 6 hours before the test
    • There are no restrictions on your meds unless you take insulin. If you do take insulin, you cannot take it 6 hours prior to the test or you will not be able to have the scan done
    • It is also important to note that we do not want you to be chewing any candy, gum or lozenges
  • If you are a diabetic, your blood sugar needs to be below 200 mg/dl or we will be unable to perform the scan. Diabetic medications other than insulin are acceptable to take such as Metformin
  • Please do not consume alcohol 24 hours before your test. The carb and sugar content of alcohol is very high.
  • We want you to wear warm, comfortable clothing avoiding all metals for the test. The scan room is chilled to prolong the machine’s life and any avoidable metals (jewelry, zippers, underwire bras) will have to be removed prior to scan

What to Wear

Regardless of what test you are undergoing today, we want you to wear warm, comfortable clothing. The scan rooms are kept cold to preserve equipment life. Avoid all metals such as zippers, buckles, underwire bras, jewelry, etc. You will have to remove any of these items if you wear them. We will provide scrubs if necessary.


  • There are no restrictions on any medications other than insulin for this test (see patient prep for details)
  • Medications to help minimize anxiety such as Valium, Ativan or Xanax are allowed as well as any pain medications to help with discomfort. If you need these medications, please bring them with you, as our facility cannot provide them.
    • If you do take any of these medications, please make sure you have someone to drive you home.
  • If you have any specific questions or concerns regarding your medications, do not hesitate to give us a call at (315) 464-2222

Common Uses

  • Oncology: Helps to identify the severity and location of the tumor(s) progression and efficiency of treatment
    • Measure lesion activity and size
    • Establish approach for therapy as well as evaluate the successes/failures of current treatment
  • Neurology: Locate focal points for seizures, help differentiate Alzheimer’s vs. dementia, and in some instances detection of brain tumors

During your PET/CT scan

  • After the technologist takes your blood sugar reading and gives you the injection of the radioactive tracer, you will be asked to rest in one of our circulation rooms with a recliner for 1 hour. This allows time for the tracer to circulate throughout your body. You are able to read, sleep or watch TV during this time
  • At the end of the 1 hour circulation period, we will then ask you to use the bathroom to empty your bladder prior to imaging. The tracer gets excreted through your kidneys and bladder so it is important that they are empty for the scan.
  • Scanning: arms will be raised above your head for 35 min
    • Exception: if you have a type of head/neck cancer, melanoma or are receiving a brain scan then arms will be by your side.
    • You can sleep, or listen to music but it is crucial that you lay still with minimal movement for optimal pictures

Length of Exam

 Circulation time after injection: 1 hour

  • On Scanner
    • Skull-Thighs: 35 min
    • Skull-Toes: 1 hour
    • Brain Scan: 15 min
  • Total time you are expected to be with us: ~2 hours

After PET/CT Scan

  • Resume your daily activities
  • No more dietary restrictions
  • The tracer will remain in your body for a few hours following the injection. It is eliminated out of your body through natural functions. Drinking extra fluids will help flush it through your system faster.

Frequently Asked Questions

  1. Tube feeding
    • Drinks like Ensure and Boost are very high in both carbs and sugars. It is important that you call our office so we can discuss how and when to modify your tube feedings for optimal pictures
  2. Results
    • If you do not have a follow up appointment scheduled with your referring physician, we recommend you call your doctor 24-48 hours after your scan to get the results (excluding weekends).
  3. Parking
    • There are two entrances: Harrison St and Adams St
    • We have a parking lot right outside of the building for patient use.
    • We do validate your parking, so you do not have to worry about the cost.
  4. Can family members stay with me for my scan?
    • Family members are required to stay in the waiting room unless the patient needs help. You will be slightly radioactive so it is important that your family members/friends do not get any unnecessary exposure.
  5. Nobody has contacted me about the exam. What do I do?
    • Our staff technologists always call to give patient prep and any other information that you may need 2 days prior to your appointment. It is very important that you get the information for your test from our office directly, not from your other doctors. If you have any questions/concerns, please do not hesitate to call at (315) 464-2222.
  6. Canceling An Appointment
    • If you cannot make your appointment or need to reschedule, please notify us at least 24 hours in advance. The drug that we administer is specific to you and can only be used that day and time that you were scheduled.
  7. I am claustrophobic; will I be able to take medications?
    • You are able to obtain a prescription from your doctor for something to help you relax if you need it. We CANNOT provide you with any medications.
  8. Why do I have a diet restriction?
    • The injection you receive is a form of radioactive sugar. The amount we inject is so minimal that eating before the test or having a high blood sugar reading will cause your body to absorb less of the drug, causing suboptimal images
  9. Why should I avoid caffeine? Is decaf okay to drink?

*Add PET/CT scan with a lot of heart uptake

  • We prefer that you avoid anything with caffeine (coffee, tea, chocolate, or soda) within 24 hours of the test. Caffeine alters the distribution of the radiopharmaceutical throughout your body, specifically to your heart.
  • Decaf coffee still has trace amounts of caffeine so it is safer to avoid it all together.
  1. Why do I need to limit my physical activity before the scan?

*Add PET/CT scan with muscle uptake

  • Please limit physical activity 24 hours before the scan. Exercising will cause more of the radiopharmaceutical to be absorbed by your muscles, creating a less accurate study.
  1. How do I dress?
    • Please dress in warm, comfortable clothing. The scan rooms are cold to preserve equipment life. Please avoid wearing any metal such as zippers, buckles, underwire bras, jewelry, etc. You will have to remove any of these items if you arrive with them on. We provide scrubs if needed.
  2. I have had an allergic reaction to contrast dyes before. Is this safe for me to have this exam?
    • IV/Oral contrast is given to you during CT/MRI scans. The material we inject is a small amount of a radioactive tracer, which has no side effects whatsoever.
  3. I have a port, can you inject in that instead of my veins?
    • The radiotracer you will be receiving can cling to the lining of the port, which could potentially mask something abnormal underneath it. If absolutely necessary we can use the ports, but will always try alternative access routes beforehand.
  4. My doctor works at a different hospital. Will he have the pictures on file?
    • We recommend that you request a DVD from us, so you can give your doctors office the pictures to keep on file. The DVD will take the technologist about 15 min to make after your exam.
    • If you have had previous imaging done at other facilities, we recommend that you bring any DVDs or paperwork from these facilities for comparison.


A physician who specializes in nuclear medicine will interpret your exam and send the result to your physician.