Nuclear radiology involves the diagnostic and therapeutic use of radioactive materials using unsealed sources.

Nuclear radiologists select, interpret, and perform procedures, including diagnostic imaging by external detection of radionuclides, diagnostic invivo or combination invivo/invitro procedures that involve the administration and detection of radioactivity by non-imaging means, and therapeutic administration of radionuclides. Nuclear medicine uses small amounts of radioactive material to diagnose and determine the severity of or treat a variety of diseases, including many types of cancers, heart disease, gastrointestinal, endocrine, neurological disorders and other abnormalities within the body.