A positron emission tomography (PET) scan is a type of nuclear medicine imaging technique that produces detailed three-dimensional (3D) images of organ functionality. A PET/CT uses a small dose of targeted radiation to outline differences between healthy and damaged tissue. The ability to visualize this comparison is useful when determining the effectiveness of treatment plans for certain medical conditions including cancer. A PET/CT combines the strengths of a PET scan and a CT scan together. A PET scan can detect the finest of changes on the cellular level while a CT scan can provide in-depth structural detail.