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.
The injected radioactive chemicals have a very short lifespan and are removed from the body fairly quickly. Sometimes, you will be advised to avoid close contact with babies or pregnant women in the few hours after your scan.
After your PET scan, a very small amount of radioactive sugar will remain in your body. So, be sure to drink plenty of water to help flush it out your system. You don't need to follow any special dietary restrictions or guidelines after your PET scan.
Drinking plenty of fluids after your scan helps to flush the radiotracer out of your system. 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.
After a PET-CT scan
After the PET-CT scan, you can return to your usual diet and activities. This includes driving. Drink lots of water. It helps wash any leftover radioactive substance and dye out of your body.
The patient is not dangerous to other friends and family, although a small amount of radioactivity may remain in the system for 8-10 hours. Patients are encouraged to drink a lot of water after the exam, as the tracer is excreted in the urine. A technologist will process the computer images.
Once you leave the imaging center, you may resume all normal activities including holding children. You probably should avoid air travel during those 24 hours because the radiation sensors at airports are extremely sensitive and you may set off alarms.
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.
If it looks as though there are still swollen (enlarged) lymph nodes after treatment, a PET-CT scan can help show if this is due to scar tissue or there are still active lymphoma cells.
A CT scan of the abdomen (belly) and pelvis exposes a person to about 10 mSv. A PET/CT exposes you to about 25 mSv of radiation.
After the Procedure
You should drink about 5 glasses of water.
Temporary side effects – The iodine-based contrast dye used in a PET CT scan can cause temporary side effects. Some PET scan side effects are diarrhea, nausea, etc., which eventually fade within a day.
This type of scan help determine whether a smaller spot is cancerous or benign, as cancerous lesions are much more likely to light up on a PET scan than benign spots or scar tissue.
A PET scan is an effective way to help discover a variety of conditions, including cancer, heart disease and brain disorders. Your health care provider can use this information to help diagnose, monitor or treat your condition.
Will I be radioactive (give off radiation) after a scan? You will not be radioactive after a CT scan. With a PET or a PET/CT scan, you will give off very low levels of radiation for around 6 hours afterwards.
When the scan lights up brightly, it means there is metabolic activity. Most aggressive cancers light up brightly, but the caveat is inflammation in the body also lights up because inflammatory cells are also metabolically active. That's why we need to verify the scan results with a needle biopsy.
Tissue that has a high rate of metabolism and a high consumption of sugar appears as especially dark spots on black-and-white PET images, and on color images as especially bright spots.
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.
PET scans may play a role in determining whether a mass is cancerous. However, PET scans are more accurate in detecting larger and more aggressive tumors than they are in locating tumors that are smaller than 8 mm a pinky nail (or half of a thumb nail) and/or less aggressive cancers.
If a PET scan is not funded by Medicare, patients have to pay between $800 and $1000.
The Day Before Your PET/CT Scan
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.
Stay on a VERY LOW-carbohydrate, NO-sugar diet. Please see Low-Carbohydrate Diet Guidelines below. Do NOT use chewing gum or mints. Do not eat or drink caffeine products (chocolate, soda, tea, coffee, or Exedrin®) for 24 hours before your exam.
A PET scan is painless and poses few risks. The scanner itself does not emit radiation, and the amount of radiotracer used for the imaging is so small as to not require the use of standard radiation precautions.