A specialized area of radiology, nuclear medicine uses the combination of very small amounts of radioactive "tagged" materials known to collect in specific areas of the body, and a computerized detector that creates an image of the area of concentration.
For instance, cells in cancer tumors are known to collect more sugar from the blood and burn it faster than normal cells. So a sugar (glucose) is "tagged" with a very mildly radioactive material and injected into the patient. Then a special gamma ray detector scans the area of the patient's body suspected of harboring a tumor. The scanner can pinpoint the areas in the body burning this blood sugar the fastest, which indicates a growing tumor.
The same basic process can be used with different materials to investigate different organs or body functions.
A Test for Organ Function and Form
Nuclear imaging is an especially useful tool because it not only shows the structure of an organ or body part; it allows evaluation of the function of the examined area as well.
This diagnostic test is especially useful in cardiac testing. Nuclear imaging is used to identify abnormal blood flow to the heart, or to assess damage to the heart after a heart attack.