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  • How PET Works

  • PET scan of melanoma
     



    9.0 mCi     3min em,    45 sec tr
    Images courtesy of University of Sherbrooke

    Positron emission tomography, or PET, is a painless diagnostic test that allows radiologists to get a unique view, at the chemical level, of the body's functions. The PET scan is different from an x-ray or CT scan in that it looks at the body's metabolic activity and provides information on the chemical level.

    During a PET scan, a radioactive tracer is injected into the body and is tracked as it moves through organs. The tracer is a radiolabeled form of glucose known as fluorodeoxyglucose (FDG). The radiation exposure associated with PET is safe and lower than that associated with conventional CT scanning. The PET scanner detects and records the signals the tracers emit. These signals are then reassembled into actual images through a computer.

    Almost all diseases alter the body's biological processes. PET is able to discover these changes in their earliest stages, often before any symptoms appear, and can provide physicians with important and accurate information. When physicians can detect cancers early in their development, they can initiate treatment plans sooner. For many cancers, early detection is a key to successful recovery. A PET scan may also eliminate the need for other diagnostic procedures and may prevent unnecessary surgical procedures.

    For more information about PET at Rhode Island Hospital or to schedule an physician-referred appointment, please call 401-444-7383.