Physicians in nuclear medicine use radioactive substances to diagnose and treat different diseases and conditions. This type of work examines molecular, physiological, metabolic, and pathologic conditions. Nuclear medicine has the ability to identify problems, abnormalities, or a disease even at its earliest stages. Diagnostic tests are not able to do this making nuclear medicine a very valuable and important specialty. A physician working in nuclear medicine can expect to work with imaging technology such as Single Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET). Common tasks done by a nuclear medicine physician include assessing damage to an organ after something like a heart attack, identifying abnormalities in structures such as the brain, and detect tumors with nuclear technology.