Nuclear medicine is a subspecialty of radiology that uses radiopharmaceuticals, taken intravenously or orally by a patient, which can localize to specific organs or cellular receptors.

The radiopharmaceuticals emit radiation that is captured by external detectors (gamma cameras), which forms images that give physicians the ability to see the extent of a disease-process in the body. Nuclear medicine tests differ from most other imaging modalities because it primarily shows the physiological function of the system being studied as opposed to traditional anatomical imaging such as CT or MRI.

Nuclear medicine is often used in organ or tissue specific imaging, though sometimes whole body scans are performed to view certain cellular receptors or functions.

Its applications include the study and detection of: kidney function, heart blood flow, lung function, cancers, bowel bleeding, infection, arthritis and tumors, among many others. For some diseases, nuclear medicine studies can identify medical problems at an earlier stage than other diagnostic tests.

In a process called image fusion or co-registration, nuclear medicine scans are superimposed on images such as CT or MRI to highlight the part of the body where the radiopharmaceutical is concentrated.

The resulting image provides precise information about the anatomy and function of organs or tissues, and allows for more accurate diagnosis which wouldn’t be possible with either test alone.