Positron Emission Tomography (PET) scan allows the diagnosis of diseases like cancer, brain disorders, and heart diseases. It uses a radioactive drug which can be swallowed, injected, or inhaled to reveal biochemical changes that occur in the tissues or organs. The drug (tracer) ejects gamma rays which can be traced and used for imaging.
The tracer used varies based on the organ or tissue that needs to be targetted. Thus, the types depend on the function of the PET scan. It can be of six types:
Fluorodeoxyglucose PET or FDG PET: Since tumours need sugars to grow, fluorodeoxyglucose is used. It is a sugar-like substance with the ability to bind with sugars. When it is introduced into the body, it gravitates towards with high concentrations of sugar. While it can be used to find tumours in any part of the body, it is specifically useful to image inflammation, infection, and brain function.