About P.E.T. P.E.T. FAQ Preparing for a P.E.T. Scan P.E.T. stands for Positron Emission Tomography. It is a safe and non-invasive imaging procedure that adds an important new dimension to a physician's ability to diagnose and manage disease. Instead of detecting changes in the physical size or structure of lesions, P.E.T. detects changes in cellular funtion by showing metabolic uptake. Since these functional changes usually take place before any physical changes can occur. P.E.T. can provide information that enables physicians to make an earlier diagnosis. Early and accurate detection of a disease can increase the effectiveness of treatment and avoid costly and invasive procedures. © 2004 University MRI