PET/CT

What is PET?

Positron Emission Tomography, also called PET imaging or a PET scan, is a type of nuclear medicine imaging. Nuclear medicine imaging uses small amounts of radioactive material to diagnose or treat a variety of diseases. PET scanning is a very advanced tool used primarily to help detect cancer and Alzheimer’s disease, to localize the origin of epileptic seizures and to locate functional heart tissue prior to cardiac surgery.

How does PET work?

With ordinary x-ray examinations, an image is made by passing x-rays through your body from an outside source. In contrast, PET uses a radioactive material called a radiopharmaceutical or radiotracer, which is injected into your bloodstream, swallowed or inhaled as a gas. This radioactive material accumulates in the organ or area of your body being examined, where it gives off a small amount of energy in the form of gamma rays. The PET scanner detects this energy and with the help of a computer creates pictures offering details on both the structure and function of organs and tissues in your body. PET evaluates the process, not the anatomy. It focuses on depicting physiologic processes within the body, such as rates of metabolism or levels of various other chemical activity, instead of showing anatomy and structure. Areas of greater intensity, called hot spots, indicate where large amounts of the radiotracer have accumulated and where there is a high level of chemical activity. Less intense areas, or cold spots, indicate a smaller concentration of radiotracer and less chemical activity.

Common uses of PET/CT

PET/CT scans are performed to:    

• detect cancer
• determine whether a cancer has spread in the body
• assess the effectiveness of a treatment plan, such as cancer therapy
• determine if a cancer has returned after treatment
• determine blood flow to the heart muscle
• determine the effects of a heart attack, or myocardial infarction, on areas of the heart
• identify areas of the heart muscle that would benefit from a procedure

How to prepare for my PET/CT scan

• Wear loose fitting, comfortable clothing, if needed we will provide a hospital gown for you to change in to
• Jewelry, watches and hairpins may interfere with the CT images, so we suggest that you leave them at home if possible. We will provide a locked, secure location for all of your personal belongings during your exam. 
• Inform your provider and the imaging scheduler of all medications you are taking
• Inform your provider and the imaging scheduler if you are pregnant, think you might be pregnant or are breastfeeding
• Inform your provider and the imaging scheduler if you are allergic to contrast materials or shellfish
• Some patients may need to be fasting prior to their exam. You will receive detailed instructions on your particular PET/CT exam from your provider and/or the imaging scheduler.

What are the benefits of PET/CT?

• The information provided by nuclear medicine examinations is unique and often unattainable using other imaging procedures.
• For many diseases, nuclear medicine scans yield the most useful information needed to make a diagnosis or to determine appropriate treatment, if any.
• Nuclear medicine is less expensive and may yield more precise information than exploratory surgery
• By identifying changes in the body at the cellular level, PET imaging may detect the early onset of disease before it is evident on other imaging tests

Is PET/CT safe?

Because the doses of radiotracer administered are small, diagnostic nuclear medicine procedures result in low radiation exposure, acceptable for diagnostic exams.Thus, the radiation risk is very low compared with the potential benefits. Nuclear medicine diagnostic procedures have been used for more than five decades, and there are no known long-term adverse effects from such low-dose exposure. Allergic reactions to radiopharmaceuticals may occur, but are extremely rare and are usually mild. Nevertheless, you should inform the nuclear medicine personnel of any allergies you may have or other problems that may have occurred during a previous nuclear medicine exam. Injection of the radiotracer may cause slight pain and redness, which should rapidly resolve.