Computed tomography (CT) is a medical imaging technology that combines multiple X-ray images with the aid of a computer to generate ‘slices’ or cross-sectional images of specific areas of the human body. The CT scan is a very detailed imaging procedure, and it often provides physicians with the most complete picture of what’s happening inside a patient’s body. This makes it particularly useful and widely used in diagnosing diseases. Compared to other diagnostic tests, however, CT scans deliver a relatively high dose of radiation to the patient.

The technologist places the patient on a special motorized table that moves the patient through a circular opening in the CT imaging system while an x-ray source and detector within the housing rotate around the patient.

Often, a radio-opaque chemical substance, called a contrast agent, is given to the patient – by mouth, injected into a vein, given by enema, or given in all three ways – before the CT scan is done. The contrast agent is used to highlight specific areas inside the body, resulting in a more diagnostic image.