The test involves injecting a very small dose of a radioactive chemical, called a radiotracer, into the vein of your arm. The tracer travels through the body and is absorbed by the organs and tissues being studied. A machine then scans you body and detects and records the energy given off by the tracer substance and, with the aid of a computer, this energy is converted into three-dimensional pictures. A physician can then look at cross-sectional images of the body organ from any angle in order to detect any functional problems.

A PET scan can measure such vital functions as blood flow, oxygen use, and glucose metabolism, which helps doctors identify abnormal from normal functioning organs and tissues. The scan can also be used to evaluate the effectiveness of a patient’s treatment plan, allowing the course of care to be adjusted if necessary.

How is a PET scan different from a CT or MRI scan?
One of the main differences between PET scans and other imaging tests like CT scan is that the PET scan reveals the cellular level metabolic changes occurring in an organ or tissue. This is important and unique because disease processes often begin with functional changes at the cellular level. A PET scan can often detect these very early changes whereas a CT scan detects changes a little later—as the disease begins to cause changes in the structure of organs or tissues.

It is essential to tell your doctor if you are pregnant or think you might be pregnant before undergoing a PET scan because of radiation exposure.

How soon will the scan results be available?
A radiologist who has specialized training in PET scans will interpret the images, write a report, and deliver the results to your doctor. This process usually takes 2 to 3 days.

(courtesy of clevelandclinic.org)

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