Positron Emission Tomography (PET)

Positron Emission Tomography (PET) is a study used to evaluate patients with certain types of disease, predominently cancer. PET gives physicians a method to look at tumors in a way never before possible. While most types of imaging are based on looking at the structure (anatomy) of the disease, PET allows physicians to look at the biology (metabolism) of the disease.

When doctors can look at both the appearance and structure of the tumor, and also look at the biochemistry of the disease, they are able to make better decisions about what will be the most effective treatment. The information obtained from a PET scan combined with structural information gained from computed tomography (CT) and magnetic resonance imaging (MRI), allows for a more accurate and detailed diagnosis.

Currently, PET is recognized as the only medical tool capable of accurately imaging and measuring the metabolic function of a disease.

In cardiology, PET is an accurate, non-invasive test which helps characterize coronary disease. It provides an accurate assessment of heart function and helps determine the need for transplant.

Brain disorders are also easily detectable with PET imaging. This scan can help identify abnormalities and help differentiate between Alzheimer’s disease and other neurological diseases. A PET scan can pinpoint a brain tumor, help define whether it is benign or malignant, and after chemotherapy determine to what extent cancer treatment has been effective.

Although annual mammograms continue to be the recommended screening exam for the early detection of breast cancer, PET can be used to help evaluate patients who are already known to have breast cancer. PET is helpful to determine if the cancer has spread to other sites in the body and is used to help monitor the effectiveness of therapy.

PET is also helpful to detect the spread of disease and monitor treatment in patients with lymphoma, colon cancer, esophageal cancer, melanoma, and lung cancer.

How is a PET Scan Done?

PET imaging is performed on a GE Discovery PET CT system. Since we are trying to study glucose metabolism, the patient is asked to refrain from eating for 8-12 hours before the study. A small amount of glucose, which is labeled with a radiotracer, is injected into a vein. After the injection, the patient waits about an hour while their body metabolizes the glucose. Cancer cells metabolize glucose faster than many normal cells and will look different in images than healthy tissues. This helps to highlight the disease sites. After the waiting period, the scan is performed. The machine looks much like a CT scanner. The patient lies on the table, and the table moves as images are captured. Exam time is approximately one hour. The images are then processed on a computer and reviewed in detail by radiologists.