It is an abbreviation of ‘Positron Emission Tomography with Computed tomography’. What it basically means is imaging the functional activity of tissues in the body based on an injection of a radioactive medicine. The tracer, most of the times, a radioactive form of glucose, is usually injected intravenously. This tracer goes to most of the cells in the body as a normal distribution, but accumulates more in cells with higher cellular activity, which corresponds to the site of disease. On the PET scan these are
seen as bright areas.