Nuclear medicine differs from general radiology in the following respects: you are not exposed to radiation from a machine outside the body, you are administered (intravenously or by mouth) a substance that is radioactive, you become radioactive for a short time, and with this radioactive substance in your body, we can actually determine if organs in the body are functioning like they should be. In addition to organ function, we can use tests like this to look at blood flow, check respiratory function, look for infections, measure organ functions, and study many other functionally related issues.
Within nuclear medicine is a group of tests that use certain types of radioactive materials to produce images called PET scans. PET stands for positron-emission tomography. A positron is similar to a beta particle. PET is a specialized type of imaging that can be used for the detection of cancer and memory disorders and even for measuring how well certain drugs are doing to get rid of cancer.