Computed axial tomography (abbreviated CAT or CT) scanning is a method of imaging that utilizes x-rays taken from various angles towards a portion of the body. Then a computer combines the views to display cross-sectional or 3-dimensional images of the portion of the body.
Purposes for CT scans include:
• Diagnosing the presence of tumors or other abnormalities
• Helping to determine whether a tumor is non-cancerous (i.e., benign) or cancerous (i.e., malignant)
• Determining how far a cancer has spread in the body (i.e., for staging of the cancer)
To provide better resolution of images, some CT scans involve the use of one of several contrast media (also called contrast dyes) that can be introduced into the body in different ways, such as:
• Being ingested (by drinking the contrast medium) to image parts of the gastrointestinal (GI) tract
• Being injected intravenously (IV; i.e., into a vein). For example, one type of contrast media contains a small amount of radioactive iodine. Patients who are allergic to iodine or shellfish should inform their physician, nuclear medicine physician, radiologist, and technician in order to avoid use of an iodine-containing contrast medium for a CT scan.
A potential side effect of certain contrast dyes is an allergic reaction.
If a contrast medium was ingested or injected during a CT scan, drinking lots of fluid after the CT scan helps to eliminate the contrast medium from the body.