Your PET Exam

Answers to the questions most commonly asked about this important diagnostic procedure

Why do I need this exam?

The information provided by your PET exam may have a major impact on your physician's diagnosis of a potential health problem - and, should a disease be detected, how he or she manages your return to health.

For example, a PET study can not only help your physician diagnose a problem; it can also help your physician predict the likely outcome of various therapeutic alternatives, pinpoint the best approach to treatment, and monitor your progress so that if you're not responding as well as expected, you can be switched to a more effective therapy immediately.

Your physician will be able to tell you precisely what he or she hopes to learn from your PET exam; just ask.

What happens once I get there?

After we've reviewed your history and any prior exams that might be available, you'll receive an injection of a radiopharmaceutical.

For most studies, you'll then have to wait a while for the radiopharmaceutical to distribute itself in the organs of interest - typically from 30 minutes to an hour. If we'll be scanning your brain, we will ask you to wait in a quiet, dimly lit room, without stimulating your brain by reading or talking. Otherwise, you may be able to read, speak, or listen to music until your scan begins - and perhaps during the scan itself.

If you're here for a heart study, on the other hand, you may not have to wait at all; the radiopharmaceuticals used for cardiac exams are often administered just before scanning begins.

What will the scan be like?

When you're ready for scanning, you'll lie on a comfortable table that moves slowly through the ring-like PET scanner as it acquires the information it needs to generate diagnostic images. We'll ask you to lie very still, because movement can interfere with the results.

You shouldn't feel a thing during the scan, which can last anywhere from 15 to 120 minutes. Then, unless the radiologist sees a need for acquiring additional information, you'll be free to leave.

How long does all this take?

The length of your exam will vary depending on what we're looking for, and what we discover along the way. Plan to spend two to three hours with us, from the moment you arrive until you're ready to leave.

What happens after the exam?

You may leave as soon as the scan is complete. Unless you've received special instructions, you'll be able to eat and drink immediately; in fact, drinking lots of fluids will help you excrete any of the radiopharmaceutical that may still be in your system.

In the meantime, we'll begin preparing the results for review by our diagnosticians, and then by your physician. He or she will let you know what we've learned.

Are there risks associated with PET?

A PET study is similar to many other diagnostic procedures, from CT and MRI to Nuclear Medicine. Although the radiation you receive is different, it's roughly equivalent to what you'd receive from a couple of chest x-rays.

Rest assured, too, that the radiopharmaceuticals used in PET have very short half-lives. That means they don't remain in your system long, so there's no reason to avoid interacting with other people once you've left. To be extra safe, wait for a few hours before getting too close to an infant, or anyone who's pregnant.