Prior to the exam: Upon arrival, you will be asked to drink a glass of oral contrast. You will have approximately 30 minutes to drink this, while sitting comfortably in the lobby area.
During the exam: A technologist will start an IV, check your blood glucose level, and give you an injection of FDG, a radioactive tracer. Once injected, you will be asked to wait for the tracer to travel through your body and accumulate in the tissues being studied. During this time, you will be asked to rest quietly and avoid movement. Also, you will be asked to drink another glass of oral contrast during this resting time period.
After the waiting time period, you will be asked to empty out your bladder. You will be instructed to remove any metal objects or articles of clothing that may cause difficulty while imaging.
The PET/CT scanner is a large machine with a hole in the middle. It looks like a donut with a table in the middle. You will be asked to lie on a table and remain still during the scan. The majority of patients will be scanned from the top of the eyes to the thighs. In some cases, a patient will be imaged from the top of the head to the bottom of the feet or just their head.
After the exam: Unless otherwise instructed, food and drink can be consumed immediately after the scan. Patients are encouraged to drink plenty of fluids after the scan to remove any remaining PET tracer and contrast agents from the body. While the scan is very safe, as a precaution, it is best to maintain distance from pregnant women and small children for 6-8 hours after your exam.
Risks: Although a radioactive tracer is used during a PET scan, the amount of radiation that you are exposed to is low and short-lived. It is not enough to affect the normal body processes, however, there are risks due to the tracer and oral contrast:
- The radioactive substance may expose radiation to the fetus of a pregnant woman or to the infant of a woman who is breastfeeding. If you are pregnant or nursing, please discuss this with the technologist.
- There is a rare risk of a major allergic reaction from the tracer.
- There is a rare risk of a major allergic reaction from the oral contrast.