PET, which was invented by NSBCC co-Director Michael Phelps, is an FDA-approved diagnostic tool for most cancers.  PET is an imaging technique that doesn’t look at the static structure of the body, such as MRI or CT imaging, but instead images metabolism. Cancerous tumors exhibit a rapid rate of growth, and so certain metabolic processes are greatly accelerated in tumors – in this case, it is the amplified metabolism of glucose by the tumors that makes them stand out as dark patches against the light grey background of non-cancerous tissues.