PET scans are very safe. There are no side effects associated with the radioactive tracers, which only remain in your body for a short time. In addition, the dose of radiation is very small — similar to several years' worth of natural radiation from the environment. Allergic reactions are very rare and usually minor.
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.
You shouldn't experience any side effects after having a PET scan and can usually go home the same day. The results of your scan won't usually be available on the same day. They'll be sent to your specialist to be discussed at your next appointment.
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).
Why do I need a PET scan? You may need a PET scan to find out if you have cancer. If you've already been diagnosed with cancer, you may need this test to see if your cancer treatment is working. A PET scan also helps diagnose and monitor heart and brain diseases.
PET scanning can give false results if chemical balances within the body are not normal. Specifically, test results of diabetic patients or patients who have eaten within a few hours prior to the examination can be adversely affected because of altered blood sugar or blood insulin levels.
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.
After your PET scan, you can go on with your normal activities straight away. The injection of the radioactive material does not make you feel any different or drowsy. There are no sedative drugs or anaesthesia used during this procedure. Your scan results will not be available immediately.
Please avoid all forms of strenuous exercise and/or physical activity for 24 hours prior to your appointment. Avoid all caffeine and de-caffeinated beverages for 24 hours prior to exam. It is important that you stay well hydrated.
After a PET-CT scan
Drink lots of water. It helps wash any leftover radioactive substance and dye out of your body. The scan results will be interpreted by the nuclear medicine physician and/or a radiologist, and that report will be sent to your doctor.
With a PET or a PET/CT scan, you will give off very low levels of radiation for around 6 hours afterwards. As a precaution, you should avoid being close to women who are pregnant during this time. It should also be safe to be around adult pets, as long as they are not pregnant.
Not all cancers show up on a PET scan. PET scan results are often used with other imaging and lab test results. Other tests are often needed to find out whether an area that collected a lot of radioactive material is non-cancerous (benign) or cancerous (malignant).
You may eat a variety of meals, some of which are high in protein. A diet that is high in protein and low in carbohydrates guarantees that your blood sugar levels stay stable. So you can have turkey, duck, cheese, steak, chicken, fish, eggs, asparagus, mushrooms, and broccoli.
After your PET-CT scan
Someone will need to take you home if you've had medicine to help you relax. You won't be able to drive for the rest of the day as you might be drowsy. The radioactive tracer gives off very small levels of radiation. This goes away very quickly.
18F-Fluorodeoxy glucose positron emission tomography‒computed tomography (18F-FDG-PET) can detect malignant lymph nodes of even normal size, thus overcoming one of the major limitations of CT.
What happens after a PET scan? Be sure to move slowly when getting up from the scanner table to avoid any dizziness or lightheadedness. You will be instructed to drink plenty of fluids and empty your bladder often for 24 to 48 hours after the test.
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.
It's important to relax, keep as still as possible, and avoid talking while you wait, as moving and speaking can affect where the radiotracer goes in your body. You can go to the toilet if you need to at any point.
Please avoid eating foods high in carbohydrates. These foods include potatoes, pasta, rice, breads, pretzels, cookies, candy, soda pop and alcoholic beverages. drink plenty of water the day before your appointment.
People who are pregnant, breastfeeding or chestfeeding should not get PET scans. The radiation may be harmful to a fetus and can pass to an infant in breast milk. Some people have an allergic reaction to PET scan radioactive tracers or CT scan contrast dyes. These allergic reactions are extremely rare and usually mild.
In general, PET scans may be used to evaluate organs and/or tissues for the presence of disease or other conditions. PET may also be used to evaluate the function of organs, such as the heart or brain. The most common use of PET is in the detection of cancer and the evaluation of cancer treatment.
CT scans are more accurate than PET scans, but PET scans can be used to diagnose cancer at an early stage. Both scans are painless and take about 30 minutes to complete. If you're unsure which scan is right for you, be sure to talk to your doctor about PET and CT protocols.
Disadvantages of PET/CT Scans
Because the radioactive material is combined with glucose and then injected into the patient, this can be a concern for some diabetic patients. Before having a PET/CT scan, a diabetic patient's blood sugar level will be evaluated, and a glucose serum blood test might be administered.
MRI scans, note that both can detect diseases and abnormalities. However, PET scans can show how your body performs at the cellular level. On the other hand, PET scans include radiation. MRI scans don't expose you to harmful radiation, which can be preferable for certain patients and annual scans.