This information will help you get ready for your positron emission tomography (PET) computed tomography (CT) scan with a gallium-68 dotatate tracer at Memorial Sloan Kettering (MSK).Back to top
About Your PET-CT
Your PET-CT scan is an imaging procedure that’s used to:
- Find and diagnose neuroendocrine tumors.
- See which areas of your body have a disease.
- See how treatment is working.
- Plan your treatment.
You’ll have a low dose CT scan done at the same time as your PET. CT scans take a fast series of x-ray pictures. The x-ray pictures are combined with your PET scan to create pictures of the soft tissues and bones in the area that was scanned.
You may also be scheduled for a diagnostic CT at the same time as your PET-CT. If you’re also having a diagnostic CT scan, ask your healthcare provider for the resource Computed Tomography (CT) Scan.
Before your PET-CT, you’ll get a radioactive medication called a tracer through an intravenous (IV) line in your arm. This is done to show differences between healthy tissue and diseased tissue. Your PET-CT will use dotatate as the tracer. Dotatate is taken up by your cells and doesn’t stay in your body long.
You may need to have contrast before your scan. Contrast is a special dye used to make it easier for your doctor to see differences in your internal organs.
There are different types of contrast used for imaging studies. The contrast used for PET-CTs is an iodinated contrast (contrast that has iodine). Iodinated contrast is usually given in 2 ways:
- Orally (by mouth)
- Through an IV catheter (thin, flexible tube) in your arm or central venous catheter (CVC)
If your doctor has ordered a PET-CT with oral contrast, you’ll be asked if you’re allergic to iodinated contrast when you check in for your appointment. Depending on whether you have these allergies, you’ll get one of the oral contrast solutions listed below. Both work the same way, are used for the same purpose, and are safe even if you have diabetes.
- Iodinated contrast
- Diluted barium sweetened with saccharin, if you’re allergic to iodinated contrast
You will need to start drinking the oral contrast 45 to 60 minutes before your PET-CT. This will give the contrast solution time to move into your bowels (intestines).
If you’re also getting a diagnostic CT scan, you may get IV contrast. If your doctor ordered a CT scan with IV contrast, the contrast material will be injected into 1 of your veins or in your CVC, if you have one.
Reactions to contrast
Some people might have an allergic reaction to contrast. Tell your healthcare provider about any allergies you have or if you’ve had a reaction to iodinated contrast (CT contrast) in the past. If your doctor feels that they need to give you medication(s) to lower your risk of having a reaction, they will give you our resource Preventing An Allergic Reaction to Contrast Dye.
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For People Receiving Anesthesia
If your healthcare provider told you that you would receive anesthesia (medication to make you sleepy) while you have your PET-CT, you must follow the additional instructions below.Back to top
Before Your PET-CT
Arrange for someone to take you home
You must have a responsible care partner take you home after your procedure. Make sure to plan this before the day of your procedure.
If you don’t have someone to take you home, call one of the agencies below. They will send someone to go home with you. There’s usually a charge for this service, and you will need to provide transportation.
Agencies in New Jersey:
Instructions for eating and drinking before your procedure
Breastfeeding and pregnancy
Tell your doctor if you’re pregnant or breastfeeding.Back to top
The Day of Your PET-CT
If you aren’t getting anesthesia (medication to make you sleepy), you must follow the instructions below. You may not be able to have your PET-CT done if you don’t follow these instructions before your procedure.
For 6 hours before you arrive for your scan:
- Do not eat or drink anything. This includes hard candy and gum.
- You may drink water before your appointment.
- If you take medications, take them with water only.
What to expect when you arrive
- Once you arrive, the tracer will be injected into your vein. You may get contrast to drink at this time.
- You’ll wait at least 1 hour for your body to absorb the tracer. How long this takes will depend on the area of your body being scanned.
- You can sleep, read, listen to music, or watch videos in the area provided for you.
- You’ll be asked to urinate (pee) just before your scan.
During Your PET-CT
When it’s time for your scan, your technologist will bring you to the scanning room and will help you onto the scanning table. The machine looks like a large doughnut, with a hole in the middle. This is the scanning ring.
Once you’re on the scanning table, the table will move slowly through the scanning ring. You must lie very still in the scanning ring until your scan is done. This can take 30 to 45 minutes, depending on the type of scan you’re having.
If you’re scheduled for a diagnostic CT scan, you’ll get the injection (shot) of contrast in your IV or CVC after your technologist takes the first series of pictures. For more information, ask your healthcare provider for the resource Computed Tomography (CT) Scan.Back to top
After Your PET-CT
- You may leave as soon as your scan is done, unless you have other tests or procedures scheduled.
- Some types of security equipment (such as at the airport or outside a tunnel) can detect radioactivity. A staff member will give you a card that says you had a test done with a radioactive tracer. If you’re stopped by law enforcement at a checkpoint, show them this card.
- Limit close contact with infants or pregnant women for 12 hours after your scan.
- If you’re breastfeeding, stop for 12 hours after your scan. During this time, you can continue to pump milk and either throw it away or store it.. After 24 hours, you can feed it to your baby. You can restart breastfeeding 12 hours after your scan.
- Drink a lot of liquids to help remove the tracer from your body.
- You can go back to your normal diet right away, unless your healthcare provider gives you other instructions.
- If your PET-CT was done for diagnostic reasons, a radiologist will read your scan. The results are usually ready for your doctor in 2 business days (Monday through Friday).
- If your PET-CT was done to help with planning your treatment, you won’t get results of this scan. Your doctor will use your pictures to plan your care.
If you have any questions or concerns, call the Molecular Imaging and Therapy Service (MITS), which is sometimes called the Nuclear Medicine service at 212-639-6652. You can reach a staff member Monday through Friday from 9:00 am to 5:00 pm. After 5:00 pm, during the weekend, and on holidays, call 212-639-2000.