PET scans are very sensitive, and increased physical activity can create problems in differentiating between normal and pathologic uptake, explained Osman.
Do not eat or drink anything, except water, for 6 hours before the exam. You may drink water, as much water as you can would be helpful, until arrival. Routine medications may be taken, unless you have been instructed otherwise.
The radioactive tracer gives off very small levels of radiation that go away very quickly. As a precaution, you should avoid close contact with pregnant women, babies and young children for 6 hours after the scan. You need someone to take you home and stay overnight if you've had medicine to help you relax (sedative).
For an oncologic FDG-PET scan, fasting is required for patients to lower their blood sugar level so that FDG would not compete with glucose for its transporters for tumor uptake during the PET scan.
You will receive a small injection of FDG (sugar water with radioactive tracer). You will sit or lie down on a comfortable chair or bed for 30-90 minutes while the FDG travels throughout your body.
When should I get my PET scan results? A radiologist with specialized training in PET scans will review the images, write a report and send it to your healthcare provider. This process usually takes 24 hours.
Can I brush my teeth before a PET/CT scan? Normal brushing without swallowing mouthwash or toothpaste within the four hour preparation timeframe will have no effect on the outcome of your PET/CT scan.
As a precaution, you may be advised to avoid close contact with pregnant women, babies and young children for a few hours after having a PET scan. This is because you'll be slightly radioactive during this time.
Before your PET-CT scan, you will get an injection of a small amount of a radioactive sugar called fluorodeoxyglucose-18. This substance is sometimes called FGD-18, radioactive glucose, or a tracer. The cells in your body absorb sugar. Areas that use more energy pick up more of the sugar.
PET scans must be interpreted carefully because noncancerous conditions can look like cancer, and some cancers do not appear on PET scans.
PET-CT Precautions
If undergoing a combination PET-CT scan, the iodine-based contrast dye used for the CT component can cause side effects, including nausea, vomiting, headache, itching, flushing, and mild rash. In rare cases, a serious, all-body allergic reaction known as anaphylaxis may occur.
Please relax and limit your movement during this time and stay warm. You can sleep, listen to music, or watch videos in the area provided for you. However, if you are receiving a brain scan, do not watch videos or listen to music.
Then, the patient will be asked to lie on a table that passes slowly through the scanner. The scanner resembles a CT scanner, but has a much larger opening. Some people fall asleep during the scan.
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.
Don't drink caffeine for 24 hours before a PET scan of your heart. Don't do any exercise or other strenuous activity for at least 48 hours before this test.
PET appointment. You should have nothing to eat or drink except water for at least 4 hours before your appointment time. This includes chewing gum, hard candy, breath mints and tobacco products. should not be taken on an empty stomach can be taken with water and 1 or 2 saltine crackers.
PET scans can show solid tumors in the brain, prostate, thyroid, lungs, and cervix. The scans can also evaluate the occurrence of colorectal, lymphoma, melanoma, and pancreatic tumors. They are also used to assess if treatment is being effective in eliminating cancer.
As a precaution, you may be advised to avoid prolonged close contact with pregnant women, babies or young children for a few hours after a PET scan, as you will be slightly radioactive during this time.
Medicare limits the number of PET scans following initial cancer treatment to three per patient. (More could be covered if deemed necessary by the doctor.) “These are good scans and appropriate in many situations,” Healy says.
The major drawback to standard PET is that the images are of substantially lower resolution than, for example, those of CT and MRI, and PET is generally poor at delineating anatomic detail.
Specific protocols may vary, but generally a PET scan follows this process: You will be asked to remove any clothing, jewelry, or other objects that may interfere with the scan. If you are asked to remove clothing, you will be given a gown to wear.
If you're having a brain PET-CT, it is important to limit brain activity before your scan. Your nurse may tell you not to read or listen to music while you're waiting for your scan. Your care team will ask you to urinate (pee) just before your scan.
Preparing for Your PET Scan
Refrain from eating for at least six hours prior to your exam since the results of your test are affected by your blood sugar level. This includes NO chewing gum or sucking/hard candy.
INSTRUCTIONS FOR YOUR PET/CT SCAN
Patient can take normal medications except for diabetic or syrup based medications. Avoid any strenuous exercise 24-36 hours prior to your appointment.