Positron Emission Tomography/Computed Tomography
PET (positron emission tomography) is a medical imaging tool that assists physicians in detecting disease. Simply stated, PET scans produce digital pictures that can, in many cases, identify various forms of cancer, damaged heart tissue, and brain disorders such as Alzheimer’s, Parkinson’s, and epilepsy. A PET scan often can detect abnormalities in cellular activity before there is any anatomical change. PET can also help physicians monitor the treatment of disease. For example, chemotherapy leads to changes in cellular activity that is observable by PET long before conventional imaging techniques can measure structural changes. A PET scan gives physicians another tool to evaluate treatments.
In one continuous full-body scan, PET captures images of minuscule changes in the body’s metabolism caused by the growth of abnormal cells, while CT (computed tomography) images simultaneously allow physicians to pinpoint the exact location, size, and shape of the diseased tissue or tumor. Essentially, small lesions or tumors are detected with PET and then precisely located with CT.
What To Expect
After you register at the front desk, a technologist will take you inside and start an intravenous line in your arm. You will then receive an injection of a radioactive glucose (sugar) that will be detected on the PET/CT scanner. Because the radioactive glucose will be injected through your intravenous line, you will not feel the injection or experience any pain or discomfort.
After the injection, the technologist will take you to a quiet room where you can rest in a recliner for about an hour to give the glucose a chance to circulate through your system.
When it is time to be scanned, you will lie flat on a table that moves incrementally through the PET/CT. Digital images are produced and assembled by the computer into a 3-D image of your body.
The PET/CT scan itself usually takes from 20 to 50 minutes, depending on the areas of the body included on the scan. You will be asked to lie on your back and remain as still as possible while we take your images. Your images will then be reviewed by the radiologist along with your history and other available x-rays and related studies. The radiologist will then send a report to your physician.
Patient Preparation
- Do not eat or drink anything for at least six hours before arriving for your PET/CT scan. If you need to take medications, you may take them with a small amount of water. If any of your medications need to be taken with food, you may eat a few saltine crackers.
- If you have diabetes, you will need to regulate your blood sugar, since the glucose in your blood will compete with the radioactive glucose that you will receive before your procedure. Your blood glucose level must be less than 200 at the time of your scan. If you take insulin (injection or pill form), it must be taken at least 4 hours before your scan. If your glucose levels are over 200, please contact us before coming in so that we can work with you and your physician to obtain a high-quality scan.
- If you need them, please bring along medications for pain, anxiety, or claustrophobia.
- Avoid strenuous exercise for 48 hours before your exam.
- Please inform the technologist of any medications that you are currently taking.